Charbonneau
Truckenbrodt
| -|0.2|13-02-2023|Reformat to CEOS-ARD PFS template. Change “CARD4L” to “CEOS-ARD”
Change “Target” to “Goal”
|-|Rosenqvist| -|0.3|29-07-2023|Refinement of GSLC specifications and alignment with NRB, POL and ORB parameters.
Annex reorganization and ORB and GSLC examples added
|[GSLC]|Charbonneau, Zebker, Rosenqvist, Albinet, Small, Truckenbrodt| -|0.3.1|26-09-2023|New items 1.7.15 (Reference orbit) and 3.7 (Flattened Phase) added as Goal|[NRB] [POL]|Charbonneau| -|0.4|26-09-2023|Item 4.3 (Geometric accuracy). Clarification added to indicate whether absolute location accuracy (ALE) estimates refer to source data, ARD product, or both.|[NRB] [POL] [ORB] [GSLC]|Small, Chapman, Charbonneau, Rosenqvist, Albinet, Truckenbrodt| -|0.4.1|11-10-2023|Add product code in summary table| |Rosenqvist| -|1.0|11-10-2023|CEOS-ARD for SAR PFS – including Geocoded Single-Look Complex v1.0 – endorsed at LSI-VC-14 | |LSI-VC| +## Document History + +| Version | Date | Description of change | Affected CEOS-ARD product | Author | +| :------ | :--------- | :----------------------------------------------------------- | :-------------------------------------- | :----------------------------------------------------------- | +| 0.1 | 14-12-2022 | Zero Draft based on the CARD4L NRB PFS v5.5, POL PFS 3.5, ORB PFS v1.0 and draft GSLC v0.1 | - | Charbonneau Truckenbrodt | +| 0.2 | 13-02-2023 | Reformat to CEOS-ARD PFS template. Change “CARD4L” to “CEOS-ARD” Change “Target” to “Goal” | - | Rosenqvist | +| 0.3 | 29-07-2023 | Refinement of GSLC specifications and alignment with NRB, POL and ORB parameters. Annex reorganization and ORB and GSLC examples added | \[GSLC] | Charbonneau, Zebker, Rosenqvist, Albinet, Small, Truckenbrodt | +| 0.3.1 | 26-09-2023 | New items 1.7.15 (Reference orbit) and 3.7 (Flattened Phase) added as Goal | \[NRB] \[POL] | Charbonneau | +| 0.4 | 26-09-2023 | Item 4.3 (Geometric accuracy). Clarification added to indicate whether absolute location accuracy (ALE) estimates refer to source data, ARD product, or both. | \[NRB] \[POL] [ORB] \[GSLC] | Small, Chapman, Charbonneau, Rosenqvist, Albinet, Truckenbrodt | +| 0.4.1 | 11-10-2023 | Add product code in summary table | | Rosenqvist | +| 1.0 | 11-10-2023 | CEOS-ARD for SAR PFS – including Geocoded Single-Look Complex v1.0 – endorsed at LSI-VC-14 | | LSI-VC | ## Contributing Authors @@ -48,7 +48,7 @@ subtitle: Synethetic Aperture Radar ## Description -**Product Family Specification Title: Synthetic Aperture Radar (CEOS-ARD SAR)** +**Product Family Specification Title: Synthetic Aperture Radar (CEOS-ARD SAR)** **Applies to:** Data collected by Synthetic Aperture Radar sensors @@ -58,56 +58,56 @@ The CEOS Analysis Ready Data (CEOS-ARD) Product Family Specification (PFS) for S This CEOS-ARD for Synthetic Aperture Radar PFS incorporates, into a single generic document, the following four CEOS-ARD SAR specifications endorsed by CEOS Land Surface Imaging-Virtual Constellation (CEOS LSI-VC): -- Normalised Radar Backscatter [version 5.5] -- Polarimetric Radar [version 3.5] -- Ocean Radar Backscatter [version 1.0] -- Geocoded Single-Look Complex [version 1.0] +- Normalised Radar Backscatter (version 5.5) +- Polarimetric Radar (version 3.5) +- Ocean Radar Backscatter (version 1.0) +- Geocoded Single-Look Complex (version 1.0) -The **CEOS-ARD Normalised Radar Backscatter [NRB]** specification describes products that have been subject to Radiometric Terrain Correction (RTC) and are provided in the Gamma-Nought ($`\gamma^0_T`$) backscatter convention (Small, 2011), which mitigates the variations from diverse observation geometries and is recommended for most land applications. An additional metadata layer can be optionally provided for conversion of $`\gamma^0_T`$ to Sigma-Nought ($`\sigma^0_T`$) backscatter layer for compatibility with legacy software or numerical models. As the **[NRB]** product contains backscatter values only, it cannot be directly used for SAR polarimetry or interferometric applications that require relative polarization phase or local phase estimates respectively. However, as an option, a “flattened” phase data layer can be provided with an **[NRB]** product for enabling InSAR analysis. The flattened phase is the interferometric phase, with respect to a reference orbit and to a DEM, for which the topographic phase contribution is removed. +The **CEOS-ARD Normalised Radar Backscatter \[NRB]** specification describes products that have been subject to Radiometric Terrain Correction (RTC) and are provided in the Gamma-Nought ($`\gamma^0_T`$) backscatter convention (Small, 2011), which mitigates the variations from diverse observation geometries and is recommended for most land applications. An additional metadata layer can be optionally provided for conversion of $`\gamma^0_T`$ to Sigma-Nought ($`\sigma^0_T`$) backscatter layer for compatibility with legacy software or numerical models. As the **\[NRB]** product contains backscatter values only, it cannot be directly used for SAR polarimetry or interferometric applications that require relative polarization phase or local phase estimates respectively. However, as an option, a “flattened” phase data layer can be provided with an **\[NRB]** product for enabling InSAR analysis. The flattened phase is the interferometric phase, with respect to a reference orbit and to a DEM, for which the topographic phase contribution is removed. -The **CEOS-ARD** **Polarimetric Radar [POL]** product format is an extension of the CEOS-ARD Normalised Radar Backscatter format **[NRB]**. This extension is required in order to better support Level-1 SLC polarimetric data, including full-polarimetric modes (e.g., RADARSAT-2, ALOS-2/4, SAOCOM-1 and future missions), and hybrid or linear dual-polarimetric modes (i.e., Compact Polarimetric mode available on RCM, SAOCOM and the upcoming NISAR mission). The **[POL]** product can be defined in two processing levels: +The **CEOS-ARD** **Polarimetric Radar \[POL]** product format is an extension of the CEOS-ARD Normalised Radar Backscatter format **\[NRB]**. This extension is required in order to better support Level-1 SLC polarimetric data, including full-polarimetric modes (e.g., RADARSAT-2, ALOS-2/4, SAOCOM-1 and future missions), and hybrid or linear dual-polarimetric modes (i.e., Compact Polarimetric mode available on RCM, SAOCOM and the upcoming NISAR mission). The **\[POL]** product can be defined in two processing levels: -The **normalised covariance matrix [CovMat]** representation (C2 or C3) which preserves the inter-channel polarimetric phase(s) and maximizes the available information for users. Interoperability within current CEOS-ARD SAR backscatter definition is preserved, since diagonal elements of the covariance matrix are backscatter intensities. Scattering information enhancement can be achieved by applying incoherent polarimetric decomposition techniques (e.g., Freeman-Durden, van Zyl, Cloude-Pottier, Yamaguchi-based) directly on the C2 or C3 matrix. +The **normalised covariance matrix \[CovMat]** representation (C2 or C3) which preserves the inter-channel polarimetric phase(s) and maximizes the available information for users. Interoperability within current CEOS-ARD SAR backscatter definition is preserved, since diagonal elements of the covariance matrix are backscatter intensities. Scattering information enhancement can be achieved by applying incoherent polarimetric decomposition techniques (e.g., Freeman-Durden, van Zyl, Cloude-Pottier, Yamaguchi-based) directly on the C2 or C3 matrix. -**Polarimetric Radar Decomposition [PRD]** refers to ARD products where polarimetric information is broken down into simplified parameters to facilitate user interpretation of the data. They are derived from coherent or incoherent polarimetric decomposition techniques. +**Polarimetric Radar Decomposition \[PRD]** refers to ARD products where polarimetric information is broken down into simplified parameters to facilitate user interpretation of the data. They are derived from coherent or incoherent polarimetric decomposition techniques. -**Notice and Limitations [POL]** +**Notice and Limitations \[POL]** -For Polarimetric Radar **[POL]** products, optimal incoherent Polarimetric Radar Decomposition **[PRD]** should be performed under the slant range projection (Gens et al., 2013, Toutin et al., 2013). In order to minimise bias in the CEOS-ARD SAR Level-2a covariance matrix product, speckle filtering and averaging of the covariance matrix should be applied in the slant range projection, and geocoding should be performed using nearest-neighbour resampling. Specifically, nearest-neighbour resampling ensures that the averaged covariance matrix elements in slant range and in geocoded ground projection are exactly the same. Consequently, the polarimetrically derived parameters are exactly equal in both approaches (assuming that no further averaging is performed on the ARD product for decomposing the polarimetric information). Bilinear and average resampling methods are also suitable for resampling the covariance matrix, but some differences with polarimetric parameters generated in slant range and then resampled (bilinear) might be observed on sloped terrains. Even if Sinc interpolation may be more robust for spatial resampling, it does not preserve covariance matrix integrity, and should consequently not be used for this ARD product. +For Polarimetric Radar **\[POL]** products, optimal incoherent Polarimetric Radar Decomposition **\[PRD]** should be performed under the slant range projection (Gens et al., 2013, Toutin et al., 2013). In order to minimise bias in the CEOS-ARD SAR Level-2a covariance matrix product, speckle filtering and averaging of the covariance matrix should be applied in the slant range projection, and geocoding should be performed using nearest-neighbour resampling. Specifically, nearest-neighbour resampling ensures that the averaged covariance matrix elements in slant range and in geocoded ground projection are exactly the same. Consequently, the polarimetrically derived parameters are exactly equal in both approaches (assuming that no further averaging is performed on the ARD product for decomposing the polarimetric information). Bilinear and average resampling methods are also suitable for resampling the covariance matrix, but some differences with polarimetric parameters generated in slant range and then resampled (bilinear) might be observed on sloped terrains. Even if Sinc interpolation may be more robust for spatial resampling, it does not preserve covariance matrix integrity, and should consequently not be used for this ARD product. -It is recommended that ARD providers who desire to distribute **[PRD]** products decompose the polarimetric information starting from Level-1 SLC data and then geocode the derived parameters rather than use the **[CovMat]** ARD product. Resampling can be performed using any of the supported methods (nearest-neighbour, bilinear, average, bi-cubic spline or Lanczos are recommended), which need to be indicated in the product metadata. Note that coherent decomposition techniques cannot be performed on **[CovMat]** ARD products. +It is recommended that ARD providers who desire to distribute **\[PRD]** products decompose the polarimetric information starting from Level-1 SLC data and then geocode the derived parameters rather than use the **\[CovMat]** ARD product. Resampling can be performed using any of the supported methods (nearest-neighbour, bilinear, average, bi-cubic spline or Lanczos are recommended), which need to be indicated in the product metadata. Note that coherent decomposition techniques cannot be performed on **\[CovMat]** ARD products. -Covariance matrix products contain a variable number of layers (or bands) with different data types depending on the polarimetric mode (full or dual) and decomposition technique. The **[CovMat]** products for the C2 matrix have 3 layers (2 real-valued diagonal elements and 1 complex-valued off-diagonal element). **[CovMat]** products for the C3 matrix have 6 layers (3 real-valued diagonal elements and 3 complex-valued off-diagonal elements). Layers that can be obtained via a complex conjugation of other layers are not provided within the product. Polarimetric Decomposition products contain typically 2 to 4 (or more) real-valued layers depending on the particular decomposition algorithm. Within the **[CovMat]** product files, ARD layers are organized in order to reduce access delays and maximize efficiency in extracting the desired information. In **[CovMat]** products, geographically contiguous samples for each layer may be stored next to each other and organized “layer by layer”. Alternatively, samples belonging to the same covariance matrix might be stored next to each other and organized “matrix by matrix”. **[PRD]** products are organized “layer by layer”, i.e., with bands corresponding to the output of the polarimetric decomposition stored next to each other. ). +Covariance matrix products contain a variable number of layers (or bands) with different data types depending on the polarimetric mode (full or dual) and decomposition technique. The **\[CovMat]** products for the C2 matrix have 3 layers (2 real-valued diagonal elements and 1 complex-valued off-diagonal element). **\[CovMat]** products for the C3 matrix have 6 layers (3 real-valued diagonal elements and 3 complex-valued off-diagonal elements). Layers that can be obtained via a complex conjugation of other layers are not provided within the product. Polarimetric Decomposition products contain typically 2 to 4 (or more) real-valued layers depending on the particular decomposition algorithm. Within the **\[CovMat]** product files, ARD layers are organized in order to reduce access delays and maximize efficiency in extracting the desired information. In **\[CovMat]** products, geographically contiguous samples for each layer may be stored next to each other and organized “layer by layer”. Alternatively, samples belonging to the same covariance matrix might be stored next to each other and organized “matrix by matrix”. **\[PRD]** products are organized “layer by layer”, i.e., with bands corresponding to the output of the polarimetric decomposition stored next to each other. ). -The **CEOS-ARD Ocean Radar Backscatter [ORB]** product specification describes products that have been projected on a geoid and are provided in the Sigma-Nought ($`\sigma^0`$) backscatter convention, which is recommended for most ocean applications. Backscatter may be calibrated to the ellipsoid ($`\sigma^0_E`$) or radiometrically terrain corrected ($`\sigma^0_T`$) prior to geometric terrain correction. As the basic **[ORB]** product contains backscatter values only, it *cannot* be directly used for SAR polarimetry or interferometric applications that require local phase estimates. Nonetheless, an advanced **[ORB]** product could include the upper diagonal of the polarimetric $`\sigma^0`$ covariance matrix for enabling advanced polarimetric analysis (similar to the **[POL]** product). +The **CEOS-ARD Ocean Radar Backscatter \[ORB]** product specification describes products that have been projected on a geoid and are provided in the Sigma-Nought ($`\sigma^0`$) backscatter convention, which is recommended for most ocean applications. Backscatter may be calibrated to the ellipsoid ($`\sigma^0_E`$) or radiometrically terrain corrected ($`\sigma^0_T`$) prior to geometric terrain correction. As the basic **\[ORB]** product contains backscatter values only, it *cannot* be directly used for SAR polarimetry or interferometric applications that require local phase estimates. Nonetheless, an advanced **\[ORB]** product could include the upper diagonal of the polarimetric $`\sigma^0`$ covariance matrix for enabling advanced polarimetric analysis (similar to the **\[POL]** product). -The **CEOS-ARD Geocoded Single-Look Complex (GSLC)** product is relevant to interferometric studies. The **[GSLC]** product is derived from the range-Doppler (i.e. slant range) Single-Look Complex (SLC) product using a DEM and the orbital state vectors and output in the map projected system. The phase of a geocoded SLC is “flattened” with respect to a reference orbit and to a DEM, to eliminate topographic phase contributions [Zebker et al., 2017 and Zheng and Zebker, 2017]. The sample spacing of the **[GSLC]** product in the map coordinate directions is comparable to the full resolution original SLC product. The **[GSLC]** product can be directly overlaid on a map or combined with other similar **[GSLC]** products to derive interferograms and create change maps, for example. Since the **[GSLC]** phase is flattened, the phase difference between two **[GSLC]** products** acquired on a same relative orbit produces an interferogram referring only to surface displacement and noise (i.e., no topographic fringes). The **[GSLC]** product may optionally** be radiometrically terrain corrected such that the squared amplitude yields $`\gamma^0_T`$. +The **CEOS-ARD Geocoded Single-Look Complex \[GSLC]** product is relevant to interferometric studies. The **\[GSLC]** product is derived from the range-Doppler (i.e. slant range) Single-Look Complex (SLC) product using a DEM and the orbital state vectors and output in the map projected system. The phase of a geocoded SLC is “flattened” with respect to a reference orbit and to a DEM, to eliminate topographic phase contributions \[Zebker et al., 2017 and Zheng and Zebker, 2017]. The sample spacing of the **\[GSLC]** product in the map coordinate directions is comparable to the full resolution original SLC product. The **\[GSLC]** product can be directly overlaid on a map or combined with other similar **\[GSLC]** products to derive interferograms and create change maps, for example. Since the **\[GSLC]** phase is flattened, the phase difference between two **\[GSLC]** products** acquired on a same relative orbit produces an interferogram referring only to surface displacement and noise (i.e., no topographic fringes). The **\[GSLC]** product may optionally** be radiometrically terrain corrected such that the squared amplitude yields $`\gamma^0_T`$. -As can be seen from the above PFS descriptions, only a few minor details in terms of generated parameters and/or the addition of supplemental data distinguish these CEOS-ARD products. In part, they are to a large extent all backward-compatible. For example, [POL] products implicitly include [NRB] products, while a coastal [NRB] or [POL] product can simply be made compatible with other [ORB] products by applying gamma-to-sigma conversion. Just as [GSLC] can be converted to [NRB], the inverse conversion can be made true by including the optional topographically flattened phase. In this way a [NRB] or [POL] product can be used like a [GSLC] for InSAR applications. Consequently, it becomes obvious that they all can follow a common approach, in terms of content and structure, in order to optimize their interoperability. +As can be seen from the above PFS descriptions, only a few minor details in terms of generated parameters and/or the addition of supplemental data distinguish these CEOS-ARD products. In part, they are to a large extent all backward-compatible. For example, \[POL] products implicitly include \[NRB] products, while a coastal \[NRB] or \[POL] product can simply be made compatible with other \[ORB] products by applying gamma-to-sigma conversion. Just as \[GSLC] can be converted to \[NRB], the inverse conversion can be made true by including the optional topographically flattened phase. In this way a \[NRB] or \[POL] product can be used like a \[GSLC] for InSAR applications. Consequently, it becomes obvious that they all can follow a common approach, in terms of content and structure, in order to optimize their interoperability. -For this generic **CEOS-ARD for Synthetic Aperture Radar** PFS, as for the individual **[NRB]**, **[POL]**, **[ORB]**, and **[GSLC]** PFSs, metadata requirements are defined under two categories: Threshold and Goal. **Threshold requirements** refer to metadata parameters or data files which are mandatorily required in a product in order to be CEOS-ARD compliant. **Goal requirements** (formerly referred to as Target) are complementary metadata parameters or data files that are desirable or more accurate but more constraining/challenging to achieve depending on the SAR missions and the data provider constraints. Since this document integrates four CEOS-ARD PFSs, it is worth noting that some requirements have been “relaxed” for a few Threshold parameters, depending on the applications/environment of the CEOS-ARD product. Exceptions are identified in the tables by specifying the usage. +For this generic **CEOS-ARD for Synthetic Aperture Radar** PFS, as for the individual **\[NRB]**, **\[POL]**, **\[ORB]**, and **\[GSLC]** PFSs, metadata requirements are defined under two categories: Threshold and Goal. **Threshold requirements** refer to metadata parameters or data files which are mandatorily required in a product in order to be CEOS-ARD compliant. **Goal requirements** (formerly referred to as Target) are complementary metadata parameters or data files that are desirable or more accurate but more constraining/challenging to achieve depending on the SAR missions and the data provider constraints. Since this document integrates four CEOS-ARD PFSs, it is worth noting that some requirements have been “relaxed” for a few Threshold parameters, depending on the applications/environment of the CEOS-ARD product. Exceptions are identified in the tables by specifying the usage. # Definitions and Abbreviations -| Term | Description | -| :------------------------: | :----------------------------------------------------------- | -|Ancillary Data|Data other than instrument measurements, originating in the instrument itself or from the satellite, required to perform processing of the data. They include orbit data, attitude data, time information, spacecraft engineering data, calibration data, data quality information, and data from other instruments.| -|Auxiliary Data|The data required for instrument processing, which does not originate in the instrument itself or from the satellite. Some auxiliary data will be generated in the ground segment, whilst other data will be provided from external sources.| -|CEOS-ARD|Committee on Earth Observation Satellites - Analysis Ready Data| -|CovMat|Normalised Radar Covariance Matrix| -|DOI|Digital Object Identifier| -|GSLC|Geocoded Single-Look Complex| -|InSAR|Interferometric Radar| -|Metadata|Structured information that describes other information or information services. With well-defined metadata, users should be able to get basic information about data without a need to have knowledge about its entire content.| -|NRB|Normalised Radar Backscatter| -|Pixel Spacing|Processed sample distance| -|POL|Polarimetric Radar| -|PRD|Polarimetric Radar Decomposition| -|RTC|Radiometrically Terrain Corrected| -|Spatial Resolution|The smallest size objects that can be distinguished by the sensor at the ground surface.| -|Spatial Sampling Distance|Spatial sampling distance is the great circle distance on the reference surface distance between adjacent spatial samples on the Earth's surface.| +| Term | Description | +| :-----------------------: | :----------------------------------------------------------- | +| Ancillary Data | Data other than instrument measurements, originating in the instrument itself or from the satellite, required to perform processing of the data. They include orbit data, attitude data, time information, spacecraft engineering data, calibration data, data quality information, and data from other instruments. | +| Auxiliary Data | The data required for instrument processing, which does not originate in the instrument itself or from the satellite. Some auxiliary data will be generated in the ground segment, whilst other data will be provided from external sources. | +| CEOS-ARD | Committee on Earth Observation Satellites - Analysis Ready Data | +| CovMat | Normalised Radar Covariance Matrix | +| DOI | Digital Object Identifier | +| GSLC | Geocoded Single-Look Complex | +| InSAR | Interferometric Radar | +| Metadata | Structured information that describes other information or information services. With well-defined metadata, users should be able to get basic information about data without a need to have knowledge about its entire content. | +| NRB | Normalised Radar Backscatter | +| Pixel Spacing | Processed sample distance | +| POL | Polarimetric Radar | +| PRD | Polarimetric Radar Decomposition | +| RTC | Radiometrically Terrain Corrected | +| Spatial Resolution | The smallest size objects that can be distinguished by the sensor at the ground surface. | +| Spatial Sampling Distance | Spatial sampling distance is the great circle distance on the reference surface distance between adjacent spatial samples on the Earth's surface. | @@ -117,256 +117,2033 @@ For this generic **CEOS-ARD for Synthetic Aperture Radar** PFS, as for the indiv *These are metadata records describing a distributed collection of pixels. The collection of pixels referred to must be contiguous in space and time. General metadata should allow the user to assess the overall suitability of the dataset and must meet the requirements listed below. The column “CEOS-ARD product” indicates to which CEOS-ARD SAR product (NRB, POL, ORB, GSLC) the parameter refers.* -| # | Parameter | CEOS-ARD product | Requirements | Self-Assessment |
|---|---|---|---|---|
| 1.1 | Traceability | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Data must be traceable to SI reference standard. Note 1: Relationship to 3.5. Traceability requires an estimate of measurement uncertainty. Note 2: Information on traceability should be available in the metadata as a single DOI landing page. | ||||
| 1.2 | Metadata Machine Readability | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Metadata is provided in a structure that enables a computer algorithm to be used consistently and to automatically identify and extract each component part for further use. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold, but metadata is formatted in accordance with CEOS-ARD SAR Metadata Specifications, v.1.0, or in a community endorsed standard that facilitates machine-readability, such as ISO 19115-2, Climate and Forecast (CF) convention and the Attribute Convention for Data Discovery (ACDD), etc. | ||||
| 1.3 | Product Type | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements CEOS-ARD product type name – or names in case of compliance with more than one product type – and, if required by the data provider, copyright. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.4 | Document Identifier | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Reference to CEOS-ARD for Synthetic Aperture Radar PFS document as URL. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.5 | Data Collection Time | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Number of source data acquisitions of the data collection is identified. The start and stop UTC time of data collection is identified in the metadata, expressed in date/time. In case of composite products, the dates/times of the first and last data takes and the per-pixel metadata 2.8 (Acquisition ID Image) is provided with the product. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.6 | Source Data Attributes | Subsection describing (detailing) each SAR acquisition used to generate the ARD product. Note: Source data attribute information are described for each acquisition and sequentially identified as acqID= 1, 2, 3, … |
| # | Parameter | CEOS-ARD product | Requirements | Self-Assessment |
|---|---|---|---|---|
| 1.6.1 | Source Data Access | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements The metadata identifies the location from where the source data can be retrieved, expressed as a URL or DOI. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements The metadata identifies an online location from where the data can be consistently and reliably retrieved by a computer algorithm without any manual intervention being required. | ||||
| 1.6.2 | Instrument | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements The instrument used to collect the data is identified in the metadata: - Satellite name - Instrument name | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold, but including a reference to the relevant CEOS Missions, Instruments and Measurements Database record. | ||||
| 1.6.3 | Source Data Acquisition Time | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements The start date and time of source data is identified in the metadata, expressed in UTC in date and time, at least to the second. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.6.4 | Source Data Acquisition Parameters | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Acquisition parameters related to the SAR antenna: - Radar band - Centre frequency - Observation mode (i.e., Beam mode name) - Polarization(s) (listed as in original product) - Antenna pointing [Right/Left] - Beam ID (i.e., Beam mode Mnemonic) | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.6.5 | Source Data Orbit Information | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Information related to the platform orbit used for data processing: - Pass direction [asc/desc) * - Orbit data source [e.g., predicted/ definite/ precise/ downlinked, etc.] * For source data crossing the North or South Pole, it is recommended to produce two distinct CEOS-ARD products and to use the appropriate “Pass direction” in each. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold, including also: - Platform heading angle expressed in degrees [0 360] from North - Orbit data file containing state vectors (minimum of 5 state vectors, from 10% of scene length before start time to 10% of scene length after stop time) - Platform (mean) altitude. | ||||
| 1.6.6 | Source Data Processing Parameters | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Processing parameters details of the source data: - Processing facility - Processing date - Software version - Product level - Product ID (file name) - Azimuth number of looks - Range number of looks (separate values for each beam, as necessary) | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold, plus additional relevant processing parameters, e.g., range- and azimuth look bandwidth and LUT applied. | ||||
| 1.6.7 | Source Data Image Attributes | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Image attributes related to the source data: - Source Data geometry (slant range/ground range) - Azimuth pixel spacing - Range pixel spacing - Azimuth resolution - Range resolution - Near range incident angle - Far range incident angle | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Geometry of the image footprint expressed in WGS84 in a standardised format (e.g., WKT). | ||||
| 1.6.8 | Sensor Calibration | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Sensor calibration parameters are identified in the metadata or can be accessed using details included in the metadata. Ideally this would support machine to machine access. | ||||
| 1.6.9 | Performance Indicators | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Provide performance indicators on data intensity noise level (NEσ0 and/or NEβ0 and/or NEγ0 (noise equivalent Sigma- and/or Beta- and/or Gamma-Nought)). Provided for each polarization channel when available. Parameter may be expressed as the mean and/or minimum and maximum noise equivalent values of the source data. Values do not need to be estimated individually for each product, but may be estimated once for each acquisition mode, and annotated on all products. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Provide additional relevant performance indicators (e.g., ENL, PSLR, ISLR, and performance reference DOI or URL). | ||||
| 1.6.10 | Source Data Polarimetric Calibration Matrices | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements The complex-valued polarimetric distortion matrices with the channel imbalance and the cross-talk applied for the polarimetric calibration. | ||||
| 1.6.11 | Mean Faraday Rotation Angle | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements The mean Faraday rotation angle estimated from the polarimetric data and/or from models with reference to the method or paper used to derive the estimate. | ||||
| 1.6.12 | Ionosphere Indicator | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Flag indicating whether the backscatter imagery is “significantly impacted” by the ionosphere (0 – false, 1 – true). Significant impact would imply that the ionospheric impact on the backscatter exceeds the radiometric calibration requirement or goal for the imagery. | ||||
| 1.7 | CEOS-ARD Product Attributes | Subsection containing information related to the CEOS-ARD product generation procedure and geographic parameters. | ||
| 1.7.1 | Product Data Access | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Processing parameters details of the CEOS-ARD product: - Processing facility - Processing date - Software version - Location from where CEOS-ARD product can be retrieved, expressed as a URL or DOI. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements The metadata identifies an online location from where the data can be consistently and reliably retrieved by a computer algorithm without any manual intervention being required. | ||||
| 1.7.2 | Auxiliary Data | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements The metadata identifies the sources of auxiliary data used in the generation process, ideally expressed as DOIs. Note: Auxiliary data includes DEMs, etc., and any additional data sources used in the generation of the product. | ||||
| 1.7.3 | Product Sample Spacing | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements CEOS-ARD product processing parameters details: - Pixel (column) spacing - Line (row) spacing | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.7.4 | Product Equivalent Number of Looks | [NRB] [POL] [ORB] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Equivalent Number of Looks (ENL) | ||||
| 1.7.5 | Product Resolution | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Average spatial resolution of the CEOS-ARD product along: - Columns - Rows | ||||
| 1.7.6 | Product Filtering | [NRB] [POL] [ORB] | Threshold (Minimum) Requirements Flag if speckle filter has been applied [true/false]. Metadata should include: - Reference to algorithm as DOI or URL - Input filtering parameters - Type - Window size in pixel units - Any other parameters defining the speckle filter used Mandatory for [POL]: Advanced polarimetric filter preserving covariance matrix properties should be applied. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.7.7 | Product Bounding Box | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Two opposite corners of the product file (bounding box, including any zero-fill values) are identified, expressed in the coordinate reference system defined in 1.7.11. Four corners of the product file are recommended for scenes crossing the Antemeridian, or the North or the South Pole. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.7.8 | Product Geographical Extent | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements The geometry of the SAR image footprint expressed in WGS84, in a standardised format (e.g., WKT Polygon). | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.7.9 | Product Image Size | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Image attributes of the CEOS-ARD product: - Number of lines - Number of pixels/lines - File header size (if applicable) - Number of no-data border pixels (if appl.) | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.7.10 | Product Pixel Coordinate Convention | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Coordinate referring to the Centre, or the Upper Left Corner or the Lower Left Corner of a pixel. Values are [pixel centre, pixel ULC or pixel LLC]. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.7.11 | Product Coordinate Reference System | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements The metadata lists the map projection (or geographical coordinates, if applicable) that was used and any relevant parameters required to geolocate data in that map projection, expressed in a standardised format (e.g., WKT). Indicate EPSG code, if defined for the CRS. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.7.12 | Look Direction Polynomials | [ORB] | Threshold (Minimum) Requirements In case the per-pixel item 2.11 (Look Direction Image) is not provided, then a list of the polynomial coefficients ai necessary to reconstruct the look direction angle*, together with an estimate of the added error from use of polynomial vs. per-pixel more accurate values, shall be provided. Example polynomial: LookDir = a1Lat2 + a2Lon2 + a3LatLon + a4Lat + a5Lon + a6 where: ai = polynomial coefficients Lat = latitude Lon = longitude Lat and Lon are the related coordinates in the product map units [‘m’, ‘deg’, ‘arcsec’] * The look direction angle represents the planar angle between north and each range direction. It is not constant in range, especially close to the poles. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.7.13 | Radar Unit Look Vector | [GSLC] | Threshold (Minimum) Requirements 3-D components radar unit look vector, specified at centre of scene, in an Earth-Centred Earth-Fixed (ECEF) coordinate system (also called Earth Centred Rotating - ECR) is provided. It consists of unit vectors from antenna to surface pixel (i.e., positive Z component). Only required if per-pixel metadata 2.12 (Radar Unit Look Vector Grid Image) is not provided. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.7.14 | Slant Range Sensor to Surface | [GSLC] | Threshold (Minimum) Requirements Slant range distance from the sensor to the surface, specified at centre of scene. Only required if per-pixel metadata 2.13 (Slant Range Sensor to Surface Image) is not provided. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 1.7.15 | Reference Orbit | [NRB] [POL] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Usage: For [NRB] & [POL] only when per-pixel metadata 3.7 (Flattened phase) is provided. For [GSLC] when a reference orbit is used instead of a virtual orbit (see Annex A 1.2). Provide the absolute orbit number used as reference for topographic phase flattening. In case a virtual orbit has been used, provide orbit parameters or orbit state vectors as DOI or URL. Provide scene-centred perpendicular baseline for the for the source data relative to the reference orbit used (for approximate use only). | ||||
| # | +Parameter | +CEOS-ARD product | +Requirements | +Self-Assessment | +
|---|---|---|---|---|
| 1.1 | +Traceability | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Data must be traceable to SI reference standard. + +Note 1: Relationship to 3.5. Traceability requires an estimate of measurement uncertainty. +Note 2: Information on traceability should be available in the metadata as a single DOI landing page. + |
+ ||||
| 1.2 | +Metadata Machine Readability | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Metadata is provided in a structure that enables a computer algorithm to be used consistently and to automatically identify and extract each component part for further use. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + + |
+
|
+ Goal (Desired) Requirements +As threshold, but metadata is formatted in accordance with CEOS-ARD SAR Metadata Specifications, v.1.0, or in a community endorsed standard that facilitates machine-readability, such as ISO 19115-2, Climate and Forecast (CF) convention and the Attribute Convention for Data Discovery (ACDD), etc. + + + + + |
+ ||||
| 1.3 | +Product Type | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +CEOS-ARD product type name – or names in case of compliance with more than one product type – and, if required by the data provider, copyright. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.4 | +Document Identifier | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Reference to CEOS-ARD for Synthetic Aperture Radar PFS document as URL. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.5 | +Data Collection Time | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Number of source data acquisitions of the data collection is identified. The start and stop UTC time of data collection is identified in the metadata, expressed in date/time. In case of composite products, the dates/times of the first and last data takes and the per-pixel metadata 2.8 (Acquisition ID Image) is provided with the product. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.6 | +Source Data Attributes | ++ |
+ Subsection describing (detailing) each SAR acquisition used to generate the ARD product. + +Note: Source data attribute information are described for each acquisition and sequentially identified as acqID= 1, 2, 3, … + |
+ + |
| 1.6.1 | +Source Data Access | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +The metadata identifies the location from where the source data can be retrieved, expressed as a URL or DOI. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +The metadata identifies an online location from where the data can be consistently and reliably retrieved by a computer algorithm without any manual intervention being required. + |
+ ||||
| 1.6.2 | +Instrument | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +The instrument used to collect the data is identified in the metadata: +- Satellite name +- Instrument name + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold, but including a reference to the relevant CEOS Missions, Instruments and Measurements Database record. + |
+ ||||
| 1.6.3 | +
+ Source Data Acquisition +Time + |
+
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +The start date and time of source data is identified in the metadata, expressed in UTC in date and time, at least to the second. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.6.4 | +Source Data Acquisition Parameters | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Acquisition parameters related to the SAR antenna: +- Radar band +- Centre frequency +- Observation mode (i.e., Beam mode name) +- Polarization(s) (listed as in original product) +- Antenna pointing [Right/Left] +- Beam ID (i.e., Beam mode Mnemonic) + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.6.5 | +Source Data Orbit Information | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Information related to the platform orbit used for data processing: +- Pass direction [asc/desc) * +- Orbit data source [e.g., predicted/ definite/ precise/ downlinked, etc.] + +* For source data crossing the North or South Pole, it is recommended to produce two distinct CEOS-ARD products and to use the appropriate “Pass direction” in each. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold, including also: +- Platform heading angle expressed in degrees [0 360] from North +- Orbit data file containing state vectors (minimum of 5 state vectors, from 10% of scene length before start time to 10% of scene length after stop time) +- Platform (mean) altitude. + |
+ ||||
| 1.6.6 | +Source Data Processing Parameters | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Processing parameters details of the source data: +- Processing facility +- Processing date +- Software version +- Product level +- Product ID (file name) +- Azimuth number of looks +- Range number of looks (separate values for each beam, as necessary) + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold, plus additional relevant processing parameters, e.g., range- and azimuth look bandwidth and LUT applied. + |
+ ||||
| 1.6.7 | +Source Data Image Attributes | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Image attributes related to the source data: +- Source Data geometry (slant range/ground range) +- Azimuth pixel spacing +- Range pixel spacing +- Azimuth resolution +- Range resolution +- Near range incident angle +- Far range incident angle + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Geometry of the image footprint expressed in WGS84 in a standardised format (e.g., WKT). + |
+ ||||
| 1.6.8 | +Sensor Calibration | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Sensor calibration parameters are identified in the metadata or can be accessed using details included in the metadata. Ideally this would support machine to machine access. + |
+ ||||
| 1.6.9 | +Performance Indicators | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Provide performance indicators on data intensity noise level (NEσ0 and/or NEβ0 and/or NEγ0 (noise equivalent Sigma- and/or Beta- and/or Gamma-Nought)). Provided for each polarization channel when available. + +Parameter may be expressed as the mean and/or minimum and maximum noise equivalent values of the source data. + +Values do not need to be estimated individually for each product, but may be estimated once for each acquisition mode, and annotated on all products. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Provide additional relevant performance indicators (e.g., ENL, PSLR, ISLR, and performance reference DOI or URL). + |
+ ||||
| 1.6.10 | +Source Data Polarimetric Calibration Matrices | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +The complex-valued polarimetric distortion matrices with the channel imbalance and the cross-talk applied for the polarimetric calibration. + |
+ ||||
| 1.6.11 | +Mean Faraday Rotation Angle | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +The mean Faraday rotation angle estimated from the polarimetric data and/or from models with reference to the method or paper used to derive the estimate. + |
+ ||||
| 1.6.12 | +Ionosphere Indicator | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Flag indicating whether the backscatter imagery is “significantly impacted” by the ionosphere (0 – false, 1 – true). Significant impact would imply that the ionospheric impact on the backscatter exceeds the radiometric calibration requirement or goal for the imagery. + |
+ ||||
| 1.7 | +CEOS-ARD Product Attributes | ++ | Subsection containing information related to the CEOS-ARD product generation procedure and geographic parameters. | ++ |
| 1.7.1 | +Product Data Access | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Processing parameters details of the CEOS-ARD product: +- Processing facility +- Processing date +- Software version +- Location from where CEOS-ARD product can be retrieved, expressed as a URL or DOI. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +The metadata identifies an online location from where the data can be consistently and reliably retrieved by a computer algorithm without any manual intervention being required. + |
+ ||||
| 1.7.2 | +Auxiliary Data | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +The metadata identifies the sources of auxiliary data used in the generation process, ideally expressed as DOIs. + +Note: Auxiliary data includes DEMs, etc., and any additional data sources used in the generation of the product. + |
+ ||||
| 1.7.3 | +Product Sample Spacing | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +CEOS-ARD product processing parameters details: +- Pixel (column) spacing +- Line (row) spacing + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.7.4 | +Product Equivalent Number of Looks | +
+ \[NRB] +\[POL] +\[ORB] + + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Equivalent Number of Looks (ENL) + |
+ ||||
| 1.7.5 | +Product Resolution | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Average spatial resolution of the CEOS-ARD product along: +- Columns +- Rows + |
+ ||||
| 1.7.6 | +
+ Product +Filtering + |
+
+ \[NRB] +\[POL] +\[ORB] + + |
+
+ Threshold (Minimum) Requirements +Flag if speckle filter has been applied [true/false]. + +Metadata should include: +- Reference to algorithm as DOI or URL +- Input filtering parameters +- Type +- Window size in pixel units +- Any other parameters defining the speckle filter used + +Mandatory for \[POL]: Advanced polarimetric filter preserving covariance matrix properties should be applied. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.7.7 | +Product Bounding Box | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Two opposite corners of the product file (bounding box, including any zero-fill values) are identified, expressed in the coordinate reference system defined in 1.7.11. + +Four corners of the product file are recommended for scenes crossing the Antemeridian, or the North or the South Pole. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.7.8 | +Product Geographical Extent | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +The geometry of the SAR image footprint expressed in WGS84, in a standardised format (e.g., WKT Polygon). + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.7.9 | +Product Image Size | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Image attributes of the CEOS-ARD product: +- Number of lines +- Number of pixels/lines +- File header size (if applicable) +- Number of no-data border pixels (if appl.) + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.7.10 | +
+ Product +Pixel Coordinate Convention + |
+
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Coordinate referring to the Centre, or the Upper Left Corner or the Lower Left Corner of a pixel. Values are [pixel centre, pixel ULC or pixel LLC]. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.7.11 | +Product Coordinate Reference System | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +The metadata lists the map projection (or geographical coordinates, if applicable) that was used and any relevant parameters required to geolocate data in that map projection, expressed in a standardised format (e.g., WKT). + +Indicate EPSG code, if defined for the CRS. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.7.12 | +Look Direction Polynomials | +\[ORB] | +
+ Threshold (Minimum) Requirements +In case the per-pixel item 2.11 (Look Direction Image) is not provided, then a list of the polynomial coefficients ai necessary to reconstruct the look direction angle*, together with an estimate of the added error from use of polynomial vs. per-pixel more accurate values, shall be provided. + +Example polynomial: +LookDir = a1Lat2 + a2Lon2 + a3LatLon + a4Lat + a5Lon + a6 + +where: +ai = polynomial coefficients +Lat = latitude +Lon = longitude +Lat and Lon are the related coordinates in the product map units [‘m’, ‘deg’, ‘arcsec’] + +* The look direction angle represents the planar angle between north and each range direction. It is not constant in range, especially close to the poles. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.7.13 | +Radar Unit Look Vector | +\[GSLC] | +
+ Threshold (Minimum) Requirements +3-D components radar unit look vector, specified at centre of scene, in an Earth-Centred Earth-Fixed (ECEF) coordinate system (also called Earth Centred Rotating - ECR) is provided. It consists of unit vectors from antenna to surface pixel (i.e., positive Z component). + +Only required if per-pixel metadata 2.12 (Radar Unit Look Vector Grid Image) is not provided. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.7.14 | +Slant Range Sensor to Surface | +\[GSLC] | +
+ Threshold (Minimum) Requirements +Slant range distance from the sensor to the surface, specified at centre of scene. +Only required if per-pixel metadata 2.13 (Slant Range Sensor to Surface Image) is not provided. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 1.7.15 | +Reference Orbit | +
+ \[NRB] +\[POL] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Usage: For \[NRB] & \[POL] only when per-pixel metadata 3.7 (Flattened phase) is provided. For \[GSLC] when a reference orbit is used instead of a virtual orbit (see Annex A 1.2). + +Provide the absolute orbit number used as reference for topographic phase flattening. In case a virtual orbit has been used, provide orbit parameters or orbit state vectors as DOI or URL. + +Provide scene-centred perpendicular baseline for the for the source data relative to the reference orbit used (for approximate use only). + |
+
| # | Parameter | CEOS-ARD product | Requirements | Self-Assessment |
|---|---|---|---|---|
| 2.1 | Metadata Machine Readability | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Metadata is provided in a structure that enables a computer algorithm to be used to consistently and automatically identify and extract each component/variable/layer for further use. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold, but metadata is formatted in accordance with CEOS-ARD SAR Metadata Specifications, v.1.0. | ||||
| 2.2 | Data Mask Image | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Mask image indicating: - Valid data - Invalid data - No data File format specifications/ contents provided in metadata: - Sample Type [Mask] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int, ...] - Bits per Sample - Byte Order - Bit Value Representation | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold, including additional bit value representations, e.g.: - Layover (masked as invalid data in threshold) - Radar shadow (masked as invalid data in threshold) - Ocean water - Land (recommended for [ORB]) - RTC applied (e.g., for maritime scenes with land samples for which RTC has been applied) - DEM gap filling (i.e., interpolated DEM over gaps) | ||||
| 2.3 | Scattering Area Image | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Usage: Recommended for scenes that include land areas. DEM-based scattering area image used for Gamma-Nought terrain normalisation is provided. This quantifies the local scattering area used to normalise for radiometric distortions induced by terrain to the measured β0 backscatter. The terrain-flattened γT0 is best understood as β0 divided by the local scattering area. File format specifications/ contents provided in metadata: - Sample Type [Scattering Area] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order | ||||
| 2.4 | Local Incident Angle Image | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements DEM-based Local Incident angle image is provided. File format specifications/ contents provided in metadata: - Sample Type [Angle] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order Note: For maritime [ORB] scenes when no land areas are covered, a geoid model could be used for the calculation of the local incident angle | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 2.5 | Ellipsoidal Incident Angle Image | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Ellipsoidal incident angle is provided. File format specifications/ contents provided in metadata: - Sample Type [Angle] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order - Reference Ellipsoid Name Note: For maritime [ORB] scenes when no land areas are covered, the ellipsoidal incident angle is nearly identical to the geoid based local incident angle. |
| # | Parameter | CEOS-ARD product | Requirements | Self-Assessment |
|---|---|---|---|---|
| 2.6 | Noise Power Image | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Estimated Noise Equivalent σ0 (or β0 or γ0, as applicable) used for noise removal, if applied, for each channel. NEσ0 and NEγ0 are both based on a simplified ellipsoid Earth model. File format specifications/ contents provided in metadata: - Sample Type [Gamma-Nought, Sigma-Nought, Beta-Nought] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order | ||||
| 2.7 | Gamma-to- Sigma Ratio Image | [NRB] [POL] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Ratio of the integrated area in the Gamma projection over the integrated area in the Sigma projection (ground). Multiplying RTC γT0 by this ratio results in an estimate of RTC σT0. File format specifications/ contents provided in metadata: - Sample Type [Ratio] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order | ||||
| 2.8 | Acquisition ID Image | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Note: Required for multi-source product only. Acquisition ID, or acquisition date, for each pixel is identified. In case of multi-temporal image stacks, use source acquisition ID (i.e., 1.6 acqID values) to list contributing images. In case of Date, data represent (integer or fractional) day offset to reference observation date [UTC]. Date used as reference (“Day 0”) is provided in the metadata. Pixels not representing a unique date (e.g., pixels averaged in image overlap zones) are flagged with a pre-set pixel value that is provided in the metadata. File format specifications/ contents provided in metadata: - Sample Type [Day, Time, ID] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per sample - Byte Order | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements In case of image composites, the sources for each pixel are uniquely identified. |
| # | Parameter | CEOS-ARD product | Requirements | Self-Assessment |
|---|---|---|---|---|
| 2.9 | Per-pixel DEM | [NRB] [POL] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Provide DEM or DSM as used during the geometric and radiometric processing of the SAR data, resampled to an exact geometric match in extent and resolution with the CEOS-ARD SAR image product. Can also be provided with [ORB] products containing land areas. File format specifications/ contents provided in metadata: - Sample Type [Height] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order | ||||
| 2.10 | Per-pixel Geoid | [ORB] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Provide Geoid as used during the geometric and radiometric processing of the SAR data, resampled to an exact geometric match in extent and resolution with the CEOS-ARD ORB image product. File format specifications/ contents provided in metadata: - Sample Type [Height] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order - Ground Sampling Distance | ||||
| # | Parameter | CEOS-ARD product | Requirements | Self-Assessment |
| 2.11 | Look Direction Image | [ORB] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Look Direction Image is provided. It represents the planar angle between north and each range direction. File format specifications/ contents provided in metadata: - Sample Type [Angle] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order | ||||
| 2.12 | Radar Unit Look Vector Grid Image | [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements 3-D components radar unit look vector, specified at each pixel in an Earth-Centred Earth-Fixed (ECEF) coordinate system (also called Earth Centred Rotating – ECR) is provided. It consists of unit vectors from the antenna to the surface pixel (i.e., positive Z component). File format specifications/ contents provided in metadata: - Sample Type [3D unit vector] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Float, ...] - Bits per Sample - Byte Order |
| # | Parameter | CEOS-ARD product | Requirements | Self-Assessment |
|---|---|---|---|---|
| 2.13 | Slant Range Sensor to Surface Image | [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Slant range distance from the sensor to the surface, specified at each pixel in an Earth-Centred Earth-Fixed (ECEF) coordinate system (also called Earth Centred Rotating – ECR) is provided. File format specifications/ contents provided in metadata: - Sample Type [Distance] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Float, ...] - Bits per Sample - Byte Order | ||||
| 2.14 | InSAR Phase Uncertainty Image | [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired)l Requirements Estimate of uncertainty in InSAR phase is provided, such as finite signal to noise ratio, quantization noise, or DEM error. Identification of which error sources are included will be provided as DOI/URL reference or brief description. It represents statistical variation from known noise sources only. File format specifications/ contents provided in metadata: - Sample Type [Angle] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Float, ...] - Bits per Sample - Byte Order |
| # | Parameter | CEOS-ARD product | Requirements | Self-Assessment |
|---|---|---|---|---|
| 2.15 | Atmospheric Phase Correction Image | [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Phase correction value at each pixel, if applied. DOI/URL reference to algorithm or brief description is provided. File format specifications/ contents provided in metadata: - Sample Type [Angle] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Float, ...] - Bits per Sample - Byte Order | ||||
| 2.16 | Ionospheric Phase Correction Image | [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Phase correction value at each pixel, if applied. DOI/URL reference to algorithm or brief description is provided. File format specifications/ contents provided in metadata: - Sample Type [Angle] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Float, ...] - Bits per Sample - Byte Order | ||||
| # | +Parameter | +CEOS-ARD product | +Requirements | +Self-Assessment | +
|---|---|---|---|---|
| 2.1 | +Metadata Machine Readability | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Metadata is provided in a structure that enables a computer algorithm to be used to consistently and automatically identify and extract each component/variable/layer for further use. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold, but metadata is formatted in accordance with CEOS-ARD SAR Metadata Specifications, v.1.0. + |
+ ||||
| 2.2 | +Data Mask Image | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Mask image indicating: +- Valid data +- Invalid data +- No data + +File format specifications/ contents provided in metadata: +- Sample Type [Mask] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int, ...] +- Bits per Sample +- Byte Order +- Bit Value Representation + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold, including additional bit value representations, e.g.: +- Layover (masked as invalid data in threshold) +- Radar shadow (masked as invalid data in threshold) +- Ocean water +- Land (recommended for \[ORB]) +- RTC applied (e.g., for maritime scenes with land samples for which RTC has been applied) +- DEM gap filling (i.e., interpolated DEM over gaps) + |
+ ||||
| 2.3 | +Scattering Area Image | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Usage: Recommended for scenes that include land areas. + +DEM-based scattering area image used for Gamma-Nought terrain normalisation is provided. This quantifies the local scattering area used to normalise for radiometric distortions induced by terrain to the measured β0 backscatter. The terrain-flattened γT0 is best understood as β0 divided by the local scattering area. + +File format specifications/ contents provided in metadata: +- Sample Type [Scattering Area] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order + |
+ ||||
| 2.4 | +Local Incident Angle Image | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +DEM-based Local Incident angle image is provided. + +File format specifications/ contents provided in metadata: +- Sample Type [Angle] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order + +Note: For maritime \[ORB] scenes when no land areas are covered, a geoid model could be used for the calculation of the local incident angle + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 2.5 | +Ellipsoidal Incident Angle Image | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Ellipsoidal incident angle is provided. + + +File format specifications/ contents provided in metadata: +- Sample Type [Angle] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order +- Reference Ellipsoid Name + +Note: For maritime \[ORB] scenes when no land areas are covered, the ellipsoidal incident angle is nearly identical to the geoid based local incident angle. + |
+ ||||
| 2.6 | +Noise Power Image | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Estimated Noise Equivalent σ0 (or β0 or γ0, as applicable) used for noise removal, if applied, for each channel. NEσ0 and NEγ0 are both based on a simplified ellipsoid Earth model. + +File format specifications/ contents provided in metadata: +- Sample Type [Gamma-Nought, Sigma-Nought, Beta-Nought] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order + |
+ ||||
| 2.7 | +Gamma-to- Sigma Ratio Image | +
+ \[NRB] +\[POL] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Ratio of the integrated area in the Gamma projection over the integrated area in the Sigma projection (ground). Multiplying RTC γT0 by this ratio results in an estimate of RTC σT0. + +File format specifications/ contents provided in metadata: +- Sample Type [Ratio] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order + |
+ ||||
| 2.8 | +Acquisition ID Image | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Note: Required for multi-source product only. + +Acquisition ID, or acquisition date, for each pixel is identified. + +In case of multi-temporal image stacks, use source acquisition ID (i.e., 1.6 acqID values) to list contributing images. + +In case of Date, data represent (integer or fractional) day offset to reference observation date [UTC]. Date used as reference (“Day 0”) is provided in the metadata. + +Pixels not representing a unique date (e.g., pixels averaged in image overlap zones) are flagged with a pre-set pixel value that is provided in the metadata. + +File format specifications/ contents provided in metadata: +- Sample Type [Day, Time, ID] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per sample +- Byte Order + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +In case of image composites, the sources for each pixel are uniquely identified. + |
+ ||||
| 2.9 | +Per-pixel DEM | +
+ \[NRB] +\[POL] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Provide DEM or DSM as used during the geometric and radiometric processing of the SAR data, resampled to an exact geometric match in extent and resolution with the CEOS-ARD SAR image product. Can also be provided with \[ORB] products containing land areas. + +File format specifications/ contents provided in metadata: +- Sample Type [Height] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order + |
+ ||||
| 2.10 | +Per-pixel Geoid |
+ \[ORB] | +
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Provide Geoid as used during the geometric and radiometric processing of the SAR data, resampled to an exact geometric match in extent and resolution with the CEOS-ARD ORB image product. + +File format specifications/ contents provided in metadata: +- Sample Type [Height] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order +- Ground Sampling Distance + |
+ ||||
| # | +Parameter | +CEOS-ARD product | +Requirements | +Self-Assessment | +
| 2.11 | +Look Direction Image |
+ \[ORB] | +
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Look Direction Image is provided. It represents the planar angle between north and each range direction. + +File format specifications/ contents provided in metadata: +- Sample Type [Angle] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order + |
+ ||||
| 2.12 | +Radar Unit Look Vector Grid Image | +\[GSLC] | +
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +3-D components radar unit look vector, specified at each pixel in an Earth-Centred Earth-Fixed (ECEF) coordinate system (also called Earth Centred Rotating – ECR) is provided. It consists of unit vectors from the antenna to the surface pixel (i.e., positive Z component). + +File format specifications/ contents provided in metadata: +- Sample Type [3D unit vector] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Float, ...] +- Bits per Sample +- Byte Order + |
+ ||||
| 2.13 | +Slant Range Sensor to Surface Image | +\[GSLC] | +
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Slant range distance from the sensor to the surface, specified at each pixel in an Earth-Centred Earth-Fixed (ECEF) coordinate system (also called Earth Centred Rotating – ECR) is provided. + +File format specifications/ contents provided in metadata: +- Sample Type [Distance] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Float, ...] +- Bits per Sample +- Byte Order + |
+ ||||
| 2.14 | +InSAR Phase Uncertainty Image | +\[GSLC] | +
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired)l Requirements +Estimate of uncertainty in InSAR phase is provided, such as finite signal to noise ratio, quantization noise, or DEM error. Identification of which error sources are included will be provided as DOI/URL reference or brief description. It represents statistical variation from known noise sources only. + +File format specifications/ contents provided in metadata: +- Sample Type [Angle] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Float, ...] +- Bits per Sample +- Byte Order + |
+ ||||
| 2.15 | +Atmospheric Phase Correction Image | +\[GSLC] | +
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Phase correction value at each pixel, if applied. DOI/URL reference to algorithm or brief description is provided. + +File format specifications/ contents provided in metadata: +- Sample Type [Angle] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Float, ...] +- Bits per Sample +- Byte Order + |
+ ||||
| 2.16 | +Ionospheric Phase Correction Image | +\[GSLC] | +
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Phase correction value at each pixel, if applied. DOI/URL reference to algorithm or brief description is provided. + +File format specifications/ contents provided in metadata: +- Sample Type [Angle] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Float, ...] +- Bits per Sample +- Byte Order + |
+
| # | Parameter | CEOS-ARD product | Requirements | Self-Assessment |
|---|---|---|---|---|
| 3.1 | Backscatter Measurements | [NRB] | Threshold (Minimum) Requirements [NRB] “Terrain-flattened” Radiometrically Terrain Corrected (RTC) Gamma-Nought backscatter coefficient (γT0) is provided for each polarization. File format specifications/contents provided in metadata: - Measurement Type [Gamma-Nought] - Backscatter Expression Convention [linear amplitude or linear power*] - Polarization [HH/HV/VV/VH] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order *Note: Transformation to the logarithm decibel scale is not required or desired as this step can be completed by the user if necessary. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 3.1 | Backscatter Measurements | [POL] | Threshold (Minimum) Requirements [POL] Measurements can be:
Normalised Radar Covariance Matrix (CovMat) Diagonal (equivalent to [NRB]) and upper diagonal elements of the terrain-flattened Gamma-Nought (γT0) Covariance Matrix are provided for coherent dual (e.g., HH-HV, VV-VH, or …) and fully polarimetric (e.g., HH- HV-VH-VV) acquisitions.
And/or
Polarimetric Radar Decomposition (PRD) The individual components of the polarimetric decomposition obtained from the terrain-flattened (Gamma-Nought (γT0)) covariance matrix. File format specifications/contents provided in metadata: - Measurement Type [CovMat/PRD] - Measurement convention unit [linear amplitude, linear power, ` `angle] - Individual covariance matrix element or/and Individual component ` `of the decomposition [C3m11, C3m12, … or H, A, alpha, or ...] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/ Float/Complex, etc.] - Bits per Sample - Byte Order Note: It is recommended to keep CovMat or PRD measurement files separated. Otherwise, specify the multi-channel format order [BIP, BIL, BSQ] | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 3.1 | Backscatter Measurements | [ORB] | Threshold (Minimum) Requirements [ORB] Geoid-corrected Sigma-Nought backscatter coefficient (σ0) is provided for each polarization. File format specifications/contents provided in metadata: - Measurement Type [Sigma-Nought] - Backscatter Expression Convention [linear amplitude or linear power*] - Backscatter Conversion Equation - Polarization [HH/HV/VV/VH] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order *Note: Transformation to the logarithm decibel scale is not required or desired as this step can be easily completed by the user if necessary. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Radiometrically Terrain-corrected Sigma-Nought backscatter coefficient (σT0) is provided for each polarization. | ||||
| 3.1 | Backscatter Measurements | [GSLC] | Threshold (Minimum) Requirements Radiometric and Phase Terrain-flattened Gamma-Nought backscatter coefficient (γT0), in complex number format, is provided for each polarization (e.g., HH, HV, VV, VH). File format specifications/contents provided in metadata: - Measurement Type [Gamma-Nought] - Backscatter Expression Convention [linear amplitude or linear power*] - Polarization [HH/HV/VV/VH] - Data Format [Raw/GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order *Note: Transformation to the logarithm decibel scale is not required or desired as this step can be easily completed by the user if necessary. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 3.2 | Scaling Conversion | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements If applicable, indicate the equation to convert pixel linear amplitude/power to logarithmic decibel scale, including, if applicable, the associated calibration (dB offset) factor, and/or the equation used to convert compressed data (int8/int16/float16) to float32. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold, but use of float32. | ||||
| 3.3 | Noise Removal | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Flag if noise removal* has been applied (Y/N). Metadata should include the noise removal algorithm and reference to the algorithm as URL or DOI. *Note: Thermal noise removal and image border noise removal to remove overall scene noise and scene edge artefacts, respectively. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements As threshold. | ||||
| 3.4 | Radiometric Terrain Correction Algorithm | [NRB] [POL] [GSLC] | Threshold (Minimum) Requirements Adjustments were made for terrain by modelling the local contributing scattering area using the preferred choice of a published peer-reviewed algorithm to produce radiometrically terrain corrected (RTC) γT0 backscatter estimates. Metadata references, e.g.: - a citable peer-reviewed algorithm - technical documentation regarding the algorithm used to generate the backscatter estimates is expressed as URLs or DOIs - the sources of auxiliary data used to make corrections Goal for [GSLC] product type Note: Examples of technical documentation include an Algorithm, Theoretical Basis Document, product user guide, etc. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Goal for [GSLC] product type Require resolution of DEM better than the output product resolution when applying terrain corrections. | ||||
| 3.5 | Radiometric Accuracy | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Uncertainty (e.g., bounds on γ0 or σ0) information is provided as document referenced as URL or DOI. SI traceability is achieved. | ||||
| 3.6 | Mean Wind- Normalised Backscatter Measurements | [ORB] | Threshold (Minimum) Requirements Not required. | Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Usage: Only for Maritime scene Mean wind-normalised (over ocean) backscatter coefficient is provided for each available polarization. It is calculated as the ratio between the backscatter intensity and a simulated backscatter intensity image generated using an ocean surface wind model such as, e.g., Quilfen et al. (1998) or Vachon and Dobson (2000) for VV and HH polarization respectively. File format specifications/contents provided in metadata: - Measurement Type [Wind-Normalised Backscatter] Backscatter Expression Convention [intensity ratio] - Polarization [HH/HV/VV/VH] - Data Format [GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order Note: Reference wind model, wind speed and direction used for reference backscattering coefficient should be provided. | ||||
| 3.7 | Flattened Phase | [NRB] [POL] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Usage: Alternative to [GSLC] product for [NRB] and [POL] products The Flattened Phase is the interferometric phase for which the topographic phase contribution is removed. It is derived from the range-Doppler SLC product using a DEM and the orbital state vectors with respect to a reference orbit (see Annex A1.2). The use of the Flattened Phase with the [NRB] or [POL] intensity (3.1 Backscatter measurement) provides the [GSLC] equivalent, as follows: GSLC = sqrt(NRB) x exp(j FlattenPhase) File format specifications/contents provided in metadata: - Measurement Type [Flattened Phase] - Reference Polarization [HH/HV/VV/VH] - Data Format [GeoTIFF/NetCDF, …] - Data Type [Int/Float, ...] - Bits per Sample - Byte Order In case of polarimetric data, indicate the reference polarization. | ||||
| # | +Parameter | +CEOS-ARD product | +Requirements | +Self-Assessment | +
|---|---|---|---|---|
| 3.1 | +Backscatter Measurements |
+
+ \[NRB] + + |
+
+ Threshold (Minimum) Requirements \[NRB] +“Terrain-flattened” Radiometrically Terrain Corrected (RTC) Gamma-Nought backscatter coefficient (γT0) is provided for each polarization. +File format specifications/contents provided in metadata: +- Measurement Type [Gamma-Nought] +- Backscatter Expression Convention [linear amplitude or linear power*] +- Polarization [HH/HV/VV/VH] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order + +*Note: Transformation to the logarithm decibel scale is not required or desired as this step can be completed by the user if necessary. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 3.1 | +Backscatter Measurements |
+
+
+ \[POL] + + |
+
+ Threshold (Minimum) Requirements \[POL] +Measurements can be: ++ Normalised Radar Covariance Matrix (CovMat) +Diagonal (equivalent to \[NRB]) and upper diagonal elements of the terrain-flattened Gamma-Nought (γT0) Covariance Matrix are provided for coherent dual (e.g., HH-HV, VV-VH, or …) and fully polarimetric (e.g., HH- HV-VH-VV) acquisitions. ++ And/or ++ Polarimetric Radar Decomposition (PRD) +The individual components of the polarimetric decomposition obtained from the terrain-flattened (Gamma-Nought (γT0)) covariance matrix. +File format specifications/contents provided in metadata: +- Measurement Type [CovMat/PRD] +- Measurement convention unit [linear amplitude, linear power, +` `angle] +- Individual covariance matrix element or/and Individual component +` `of the decomposition [C3m11, C3m12, … or H, A, alpha, or ...] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/ Float/Complex, etc.] +- Bits per Sample +- Byte Order + +Note: It is recommended to keep CovMat or PRD measurement files separated. Otherwise, specify the multi-channel format order [BIP, BIL, BSQ] + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 3.1 | +Backscatter Measurements |
+
+
+ \[ORB] + + |
+
+ Threshold (Minimum) Requirements \[ORB] +Geoid-corrected Sigma-Nought backscatter coefficient (σ0) is provided for each polarization. + +File format specifications/contents provided in metadata: +- Measurement Type [Sigma-Nought] +- Backscatter Expression Convention [linear amplitude or linear power*] +- Backscatter Conversion Equation +- Polarization [HH/HV/VV/VH] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order +*Note: Transformation to the logarithm decibel scale is not required or desired as this step can be easily completed by the user if necessary. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Radiometrically Terrain-corrected Sigma-Nought backscatter coefficient (σT0) is provided for each polarization. + |
+ ||||
| 3.1 | +Backscatter Measurements |
+ \[GSLC] | +
+ Threshold (Minimum) Requirements +Radiometric and Phase Terrain-flattened Gamma-Nought backscatter coefficient (γT0), in complex number format, is provided for each polarization (e.g., HH, HV, VV, VH). + +File format specifications/contents provided in metadata: +- Measurement Type [Gamma-Nought] +- Backscatter Expression Convention [linear amplitude or linear power*] +- Polarization [HH/HV/VV/VH] +- Data Format [Raw/GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order + +*Note: Transformation to the logarithm decibel scale is not required or desired as this step can be easily completed by the user if necessary. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 3.2 | +Scaling Conversion | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +If applicable, indicate the equation to convert pixel linear amplitude/power to logarithmic decibel scale, including, if applicable, the associated calibration (dB offset) factor, and/or the equation used to convert compressed data (int8/int16/float16) to float32. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold, but use of float32. + |
+ ||||
| 3.3 | +Noise Removal | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Flag if noise removal* has been applied (Y/N). Metadata should include the noise removal algorithm and reference to the algorithm as URL or DOI. + +*Note: Thermal noise removal and image border noise removal to remove overall scene noise and scene edge artefacts, respectively. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +As threshold. + |
+ ||||
| 3.4 | +Radiometric Terrain Correction Algorithm | +
+ \[NRB] +\[POL] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Adjustments were made for terrain by modelling the local contributing scattering area using the preferred choice of a published peer-reviewed algorithm to produce radiometrically terrain corrected (RTC) γT0 backscatter estimates. + +Metadata references, e.g.: +- a citable peer-reviewed algorithm +- technical documentation regarding the algorithm used to generate the backscatter estimates is expressed as URLs or DOIs +- the sources of auxiliary data used to make corrections + +Goal for \[GSLC] product type + +Note: Examples of technical documentation include an Algorithm, Theoretical Basis Document, product user guide, etc. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements + +Goal for \[GSLC] product type + +Require resolution of DEM better than the output product resolution when applying terrain corrections. + |
+ ||||
| 3.5 | +Radiometric Accuracy |
+
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Uncertainty (e.g., bounds on γ0 or σ0) information is provided as document referenced as URL or DOI. SI traceability is achieved. + |
+ ||||
| 3.6 | +Mean Wind- Normalised Backscatter Measurements | +\[ORB] | +
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Usage: Only for Maritime scene + +Mean wind-normalised (over ocean) backscatter coefficient is provided for each available polarization. It is calculated as the ratio between the backscatter intensity and a simulated backscatter intensity image generated using an ocean surface wind model such as, e.g., Quilfen et al. (1998) or Vachon and Dobson (2000) for VV and HH polarization respectively. + +File format specifications/contents provided in metadata: +- Measurement Type [Wind-Normalised Backscatter] +Backscatter Expression Convention [intensity ratio] +- Polarization [HH/HV/VV/VH] +- Data Format [GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order + +Note: Reference wind model, wind speed and direction used for reference backscattering coefficient should be provided. + |
+ ||||
| 3.7 | +Flattened Phase | +
+ \[NRB] +\[POL] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Usage: Alternative to \[GSLC] product for \[NRB] and \[POL] products +The Flattened Phase is the interferometric phase for which the topographic phase contribution is removed. It is derived from the range-Doppler SLC product using a DEM and the orbital state vectors with respect to a reference orbit (see Annex A1.2). The use of the Flattened Phase with the \[NRB] or \[POL] intensity (3.1 Backscatter measurement) provides the \[GSLC] equivalent, as follows: +GSLC = sqrt(NRB) x exp(j FlattenPhase) +File format specifications/contents provided in metadata: +- Measurement Type [Flattened Phase] +- Reference Polarization [HH/HV/VV/VH] +- Data Format [GeoTIFF/NetCDF, …] +- Data Type [Int/Float, ...] +- Bits per Sample +- Byte Order + +In case of polarimetric data, indicate the reference polarization. + |
+
| # | Parameter | CEOS-ARD product | Requirements | Self-Assessment |
|---|---|---|---|---|
| 4.1 | Geometric Correction Algorithm | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Metadata references, e.g.: - A metadata citable peer-reviewed algorithm, - Technical documentation regarding the implementation of that algorithm expressed as URLs or DOIs - The sources of auxiliary data used to make corrections. - Resampling method used for geometric processing of the source data. Note: Examples of technical documentation can include e.g., an Algorithm Theoretical Basis Document (ATBD), a product user guide. | ||||
| 4.2 | Digital Model | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Usage: For products including land areas a) During ortho-rectification, the data provider shall use the same DEM that was used for the radiometric terrain flattening to ensure consistency of the data stack. b) Provide reference to Digital Elevation Model used for geometric terrain correction. c) Provide reference to Earth Gravitational Model (EGM) used for geometric correction | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements a) A DEM with comparable or better resolution to the resolution of the output CEOS-ARD product shall be used if available. Else, the upsampled DEM is identified. b) Resampling method used for preparation of the DEM. c) Method used for resampling the EGM. | ||||
| 4.3 | Geometric Accuracy | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Accurate geolocation is a prerequisite to radar processing to correct for terrain and to enable interoperability between radar sensors. The absolute geolocation error (ALE) for a sensor is typically assessed through analysis of Single Look Complex (SLC) imagery and measured along the slant range and azimuth directions (case A: SLC ALE). The end-to-end “ARD” ALE of the final CEOS-ARD product could be measured directly in the final image product in the chosen map projection, i.e., in the map coordinate directions: e.g., Northing and Easting (case B: ARD ALE). Providing accuracy estimates based on measurements following at least one scheme (A or B or both) meets the threshold requirement. Estimates of the ALE is provided as a bias and a standard deviation, with (Case A) SLC ALE expressed in slant range and azimuth, and (Case B) ARD ALE expressed in map projection dimensions. Note 1: This assessment is often made through comparison of measured corner reflector positions with their projected location in the imagery. In some cases, other mission calibration/validation results may be used. Note 2: The ALE is not typically assessed for every processed image, but through an ALE assessment by the data processing team characterizing all or (usually a subset) of the generated products. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Output product sub-sample accuracy should be less than or equal to 0.1 (slant range) pixel radial root mean square error (rRMSE). Provide documentation of estimates of ALE as DOI or URL. | ||||
| 4.4 | Geometric Refined Accuracy | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements Not required. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Values provided under 4.3 Geometric accuracy are provided by the SAR mission Cal/Val team. CEOS-ARD processing steps could include method refining the geometric accuracy, such as cross-correlation of the SAR data in slant range with a SAR scene simulated from a DSM or DEM. Methodology used (name and reference), quality flag, geometric standard deviation values should be provided. | ||||
| 4.5 | Gridding Convention | [NRB] [POL] [ORB] [GSLC] | Threshold (Minimum) Requirements A consistent gridding/sampling frame is used. The origin is chosen to minimise any need for subsequent resampling between multiple products (be they from the same or different providers). This is typically accomplished via a “snap to grid” in relation to the most proximate grid tile in a global system.* * If a product hierarchy of resolutions exists (or is planned), the multiple resolutions should nest within each other (e.g., 12.5m, 25m, 50m, 100m, etc.), and not be disjoint. | Achieved level: Threshold / Goal Explanation / Justification: … Other feedback: … |
Goal (Desired) Requirements Provide DOI or URL to gridding convention used. When multiple providers share a common map projection, providers are encouraged to standardise the origins of their products among each other. In the case of UTM/UPS coordinates, the upper left corner coordinates should be set to an integer multiple of sample intervals from a 100 km by 100 km grid tile of the Military Grid Reference System's 100k coordinates (“snap to grid”). For products presented in geographic coordinates (latitude and longitude), the origin should be set to an integer multiple of samples in relation to the closest integer degree. | ||||
| # | +Parameter | +CEOS-ARD product | +Requirements | +Self-Assessment | +
|---|---|---|---|---|
| 4.1 | +Geometric Correction Algorithm | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Metadata references, e.g.: +- A metadata citable peer-reviewed algorithm, +- Technical documentation regarding the implementation of that algorithm expressed as URLs or DOIs +- The sources of auxiliary data used to make corrections. +- Resampling method used for geometric processing of the source data. + +Note: Examples of technical documentation can include e.g., an Algorithm Theoretical Basis Document (ATBD), a product user guide. + |
+ ||||
| 4.2 | +
+ Digital Model + |
+
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Usage: For products including land areas + +a) During ortho-rectification, the data provider shall use the same DEM that was used for the radiometric terrain flattening to ensure consistency of the data stack. +b) Provide reference to Digital Elevation Model used for geometric terrain correction. +c) Provide reference to Earth Gravitational Model (EGM) used for geometric correction + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +a) A DEM with comparable or better resolution to the resolution of the output CEOS-ARD product shall be used if available. Else, the upsampled DEM is identified. +b) Resampling method used for preparation of the DEM. +c) Method used for resampling the EGM. + |
+ ||||
| 4.3 | +Geometric Accuracy | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Accurate geolocation is a prerequisite to radar processing to correct for terrain and to enable interoperability between radar sensors. +The absolute geolocation error (ALE) for a sensor is typically assessed through analysis of Single Look Complex (SLC) imagery and measured along the slant range and azimuth directions (case A: SLC ALE). The end-to-end “ARD” ALE of the final CEOS-ARD product could be measured directly in the final image product in the chosen map projection, i.e., in the map coordinate directions: e.g., Northing and Easting (case B: ARD ALE). Providing accuracy estimates based on measurements following at least one scheme (A or B or both) meets the threshold requirement. +Estimates of the ALE is provided as a bias and a standard deviation, with (Case A) SLC ALE expressed in slant range and azimuth, and (Case B) ARD ALE expressed in map projection dimensions. +Note 1: This assessment is often made through comparison of measured corner reflector positions with their projected location in the imagery. In some cases, other mission calibration/validation results may be used. Note 2: The ALE is not typically assessed for every processed image, but through an ALE assessment by the data processing team characterizing all or (usually a subset) of the generated products. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Output product sub-sample accuracy should be less than or equal to 0.1 (slant range) pixel radial root mean square error (rRMSE). + +Provide documentation of estimates of ALE as DOI or URL. + |
+ ||||
| 4.4 | +Geometric Refined Accuracy | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +Not required. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Values provided under 4.3 Geometric accuracy are provided by the SAR mission Cal/Val team. + +CEOS-ARD processing steps could include method refining the geometric accuracy, such as cross-correlation of the SAR data in slant range with a SAR scene simulated from a DSM or DEM. + +Methodology used (name and reference), quality flag, geometric standard deviation values should be provided. + |
+ ||||
| 4.5 | +Gridding Convention | +
+ \[NRB] +\[POL] +\[ORB] +\[GSLC] + |
+
+ Threshold (Minimum) Requirements +A consistent gridding/sampling frame is used. The origin is chosen to minimise any need for subsequent resampling between multiple products (be they from the same or different providers). This is typically accomplished via a “snap to grid” in relation to the most proximate grid tile in a global system.* + +* If a product hierarchy of resolutions exists (or is planned), the multiple resolutions should nest within each other (e.g., 12.5m, 25m, 50m, 100m, etc.), and not be disjoint. + |
+
+ Achieved level: Threshold / Goal +Explanation / Justification: … +Other feedback: … + |
+
|
+ Goal (Desired) Requirements +Provide DOI or URL to gridding convention used. + +When multiple providers share a common map projection, providers are encouraged to standardise the origins of their products among each other. + +In the case of UTM/UPS coordinates, the upper left corner coordinates should be set to an integer multiple of sample intervals from a 100 km by 100 km grid tile of the Military Grid Reference System's 100k coordinates (“snap to grid”). + +For products presented in geographic coordinates (latitude and longitude), the origin should be set to an integer multiple of samples in relation to the closest integer degree. + |
+
[NRB]
[POL]
[ORB]
|Product Equivalent Number of Looks||| -|1.7.5|[ALL]|Product Resolution||| -|1.7.6|[NRB]
[POL]
[ORB]
|Product Filtering||| -|1.7.7|[ALL]|Product Bounding Box||| -|1.7.8|[ALL]|Product Geographical Extent||| -|1.7.9|[ALL]|Product Image Size||| -|1.7.10|[ALL]|Product Pixel Coordinate Convention||| -|1.7.11|[ALL]|Product Coordinate Reference System||| -|1.7.12|[ORB]|Look Direction Polynomials||| -|1.7.13|[GSLC]|Radar Unit Look Vector||| -|1.7.14|[GSLC]|Slant Range Sensor to Surface||| -|1.7.15|[NRB]
[POL]
[GSLC]
|Reference Orbit||| -|**2**|**CEOS-ARD product**|**Per-Pixel Metadata**||| -|2.1|[ALL]|Metadata Machine Readability||| -|2.2|[ALL]|Data Mask Image||| -|2.3|[ALL]|Scattering Area Image||| -|2.4|[ALL]|Local Incident Angle Image||| -|2.5|[ALL]|Ellipsoidal Incident Angle Image||| -|2.6|[ALL]|Noise Power Image||| -|2.7|[NRB]
[POL]
[GSLC]
|Gamma-to-Sigma Ratio Image||| -|2.8|[ALL]|Acquisition ID Image||| -|2.9|[NRB]
[POL]
[GSLC]
|Per-pixel DEM||| -|2.10|[ORB]|Per-pixel Geoid||| -|2.11|[ORB]|Look Direction Image||| -|2.12|[GSLC]|Radar Unit Look Vector Grid Image||| -|2.13|[GSLC]|Slant Range Sensor to Surface Image||| -|2.14|[GSLC]|InSAR Phase Uncertainty Image||| -|2.15|[GSLC]|Atmospheric Phase Correction Image||| -|2.16|[GSLC]|Ionospheric Phase Correction Image||| -||||**Threshold**|**Goal**| -|**3**|**CEOS-ARD product**|**Radiometrically Corrected Measurements**||| -|3.1|[ALL]|Backscatter Measurements||| -|3.2|[ALL]|Scaling Conversion ||| -|3.3|[ALL]|Noise Removal||| -|3.4|[NRB]
[POL]
[GSLC]
|Radiometric Terrain Correction Algorithms||| -|3.5|[ALL]|Radiometric Accuracy||| -|3.6|[ORB]|Mean Wind-Normalised Backscatter Measurements||| -|3.7|[NRB]Specification of LUT on ingest.
(Gamma - par\_RSAT2\_SLC/SG)
| -|3. Generate covariance matrix elements|Gamma – COV\_MATRIX| -|4. Radiometric terrain normalisation|Gamma - geo\_radcal2| -|5. Speckle filtering (Boxcar or Sigma Lee)|Custom scripting| -|6. Geometric terrain correction/Geocoding|Gamma – gc\_map and geocode\_back| -|7. Create metadata|Custom scripting| - +| Step | Implementation option | +| :----------------------------------------------------------- | :----------------------------------------------------------- | +| 1. Orbital data refinement | Check xml date and delivered format. RADARSAT-2, pre EDOT (July 2015) replace. Post July 2015, check if ‘DEF’, otherwise replace. (Gamma - RSAT2\_vec) | +| 2. Apply radiometric scaling Look-Up Table (LUT) to Beta-Nought | Specification of LUT on ingest. (Gamma - par_RSAT2_SLC/SG) | +| 3. Generate covariance matrix elements | Gamma – COV_MATRIX | +| 4. Radiometric terrain normalisation | Gamma - geo_radcal2 | +| 5. Speckle filtering (Boxcar or Sigma Lee) | Custom scripting | +| 6. Geometric terrain correction/Geocoding | Gamma – gc_map and geocode_back | +| 7. Create metadata | Custom scripting | diff --git a/Specifications/Synthetic-Aperture-Radar/annex-1.2-topographic-phase-removal.md b/Specifications/Synthetic-Aperture-Radar/annex-1.2-topographic-phase-removal.md index 3ffe129..b7536d4 100644 --- a/Specifications/Synthetic-Aperture-Radar/annex-1.2-topographic-phase-removal.md +++ b/Specifications/Synthetic-Aperture-Radar/annex-1.2-topographic-phase-removal.md @@ -1,72 +1,70 @@ - +### A1.2: Topographic phase removal -# A1.2: Topographic phase removal -InSAR analysis capabilities from CEOS-ARD SAR products are enabled with **[GSLC]** products, which is also the case when the Flattened Phase per-pixel data (item 3.7) are included in the **[NRB]** or **[POL]** products. This is made possible since the simulated topographic phase relative to a given reference orbit has been subtracted. +InSAR analysis capabilities from CEOS-ARD SAR products are enabled with **\[GSLC]** products, which is also the case when the Flattened Phase per-pixel data (item 3.7) are included in the **\[NRB]** or **\[POL]** products. This is made possible since the simulated topographic phase relative to a given reference orbit has been subtracted. -From classical approach with SLC data, interferometric phase $`\Delta \varphi_{1-2}`$ between two SAR acquisitions is composed of a topographic phase $`\Delta \varphi_{\text{Topo}\textunderscore1-2}`$, a surface displacement phase $`\Delta \varphi_{\text{Disp}\textunderscore1-2}`$ and other noise terms $`\Delta \varphi_{\text{Noise}\textunderscore1-2}`$ (Eq. A1.1). The topographic phase consists to the difference in geometrical path length from each of the two antenna positions to the point on the SAR image ($`\varphi_{\text{DEM}\textunderscore\text{SLC}}`$) and is a function of their orbital baseline distance (Eq. A1.2). The surface displacement phase is related to the displacement of the surface that occurred in between the two acquisitions. The noise term is the function of the radar signal interaction with the atmosphere and the ionosphere during each acquisition and function of the system noise. +From classical approach with SLC data, interferometric phase $`\Delta \varphi_{1-2}`$ between two SAR acquisitions is composed of a topographic phase $`\Delta \varphi_{\text{Topo}\_1-2}`$, a surface displacement phase $`\Delta \varphi_{\text{Disp}\_1-2}`$ and other noise terms $`\Delta \varphi_{\text{Noise}\_1-2}`$ (Eq. A1.1). The topographic phase consists to the difference in geometrical path length from each of the two antenna positions to the point on the SAR image ($`\varphi_{\text{DEM}\_\text{SLC}}`$) and is a function of their orbital baseline distance (Eq. A1.2). The surface displacement phase is related to the displacement of the surface that occurred in between the two acquisitions. The noise term is the function of the radar signal interaction with the atmosphere and the ionosphere during each acquisition and function of the system noise. -$$\tag{Eq. A1.1} -\Delta \varphi_{1-2} = \Delta \varphi_{\text{Topo}\textunderscore1-2} + \Delta \varphi_{\text{Disp}\textunderscore1-2} + \Delta \varphi_{\text{Noise}\textunderscore1-2} +$$ +\tag{Eq. A1.1} +\Delta \varphi_{1-2} = \Delta \varphi_{\text{Topo}\_1-2} + \Delta \varphi_{\text{Disp}\_1-2} + \Delta \varphi_{\text{Noise}\_1-2} $$ -Where +Where -$$\tag{Eq. A1.2} -\Delta \varphi_{\text{Topo}\textunderscore1-2} = \varphi_{\text{DEM}\textunderscore\text{SLC}\textunderscore1} = \varphi_{\text{DEM}\textunderscore\text{SLC}\textunderscore2} +$$ +\tag{Eq. A1.2} +\Delta \varphi_{\text{Topo}\_1-2} = \varphi_{\text{DEM}\_\text{SLC}\_1} = \varphi_{\text{DEM}\_\text{SLC}\_2} $$ -Since CEOS-ARD products are already geocoded, it is important to remove the wrapped simulated topographic phase $`\varphi_{\text{SimDEM}\textunderscore\text{SLC}}`$ from the data in slant range (Eq. A1.3) during their production, before the geocoding step. The key here is to simulate the topographic phase relatively to a constant reference orbit, as done in a regular InSAR processing. There are two different ways to simulate the topographic phase: +Since CEOS-ARD products are already geocoded, it is important to remove the wrapped simulated topographic phase $`\varphi_{\text{SimDEM}\_\text{SLC}}`$ from the data in slant range (Eq. A1.3) during their production, before the geocoding step. The key here is to simulate the topographic phase relatively to a constant reference orbit, as done in a regular InSAR processing. There are two different ways to simulate the topographic phase: 1. The use of a virtual circular orbit above a nonrotating planet (Zebker et al., 2010) 2. The use of a specific orbit cycle or a simulated orbit of the SAR mission -In both cases, the InSAR topographic phase $`\Delta \varphi_{\text{Topo}\textunderscore\text{OrbRef}-2}`$ is simulated against the position of a virtual sensor $`\Delta \varphi_{\text{Topo}\textunderscore\text{OrbRef}}`$ lying on a reference orbit, instead of being simulated relatively to an existing reference SAR acquisition ($`\varphi_{\text{DEM}\textunderscore\text{SLC}\textunderscore1}`$). The use of a virtual circular orbit is a more robust approach since the reference orbit is defined at a fixed height above scene nadir and assuming the reference orbital height constant for all CEOS-ARD products. While with the second approach, the CEOS-ARD data producer must select a specific archived orbit cycle of the SAR mission or define a simulated one, from which the relative orbit, matching the one of the SAR acquisitions to be processed (to be converted to CEOS-ARD), is defined as the reference orbit. With this second approach, it is important to always use the same orbit cycle (or simulated orbit) for all the CEOS-ARD produced for a mission, in order to preserve the relevant compensated phase in between them. Providing absolute reference orbit number information in the metadata (item 1.7.15) allows users to validate the InSAR feasibility in between CEOS-ARD products. +In both cases, the InSAR topographic phase $`\Delta \varphi_{\text{Topo}\_\text{OrbRef}-2}`$ is simulated against the position of a virtual sensor $`\Delta \varphi_{\text{Topo}\_\text{OrbRef}}`$ lying on a reference orbit, instead of being simulated relatively to an existing reference SAR acquisition ($`\varphi_{\text{DEM}\_\text{SLC}\_1}`$). The use of a virtual circular orbit is a more robust approach since the reference orbit is defined at a fixed height above scene nadir and assuming the reference orbital height constant for all CEOS-ARD products. While with the second approach, the CEOS-ARD data producer must select a specific archived orbit cycle of the SAR mission or define a simulated one, from which the relative orbit, matching the one of the SAR acquisitions to be processed (to be converted to CEOS-ARD), is defined as the reference orbit. With this second approach, it is important to always use the same orbit cycle (or simulated orbit) for all the CEOS-ARD produced for a mission, in order to preserve the relevant compensated phase in between them. Providing absolute reference orbit number information in the metadata (item 1.7.15) allows users to validate the InSAR feasibility in between CEOS-ARD products. -$$ \tag{Eq. A1.3} -\varphi_{\text{Flattended}\textunderscore\text{SLC}\textunderscore2} = \varphi_{\text{SLC}\textunderscore2} - \Delta\varphi_{\text{Topo}\textunderscore\text{OrbRef}-2} $$ +$$ +\tag{Eq. A1.3} +\varphi_{\text{Flattended}\_\text{SLC}\_2} = \varphi_{\text{SLC}\_2} - \Delta\varphi_{\text{Topo}\_\text{OrbRef}-2} +$$ -This procedure is equivalent to bring the position of the sensor platform of all the SAR acquisitions at the same orbital position (i.e., zeros baseline distance in between), which results in a Flattened phase $`\varphi_{\text{Flattended}\textunderscore\text{SLC}}`$, independent of the local topography. +This procedure is equivalent to bring the position of the sensor platform of all the SAR acquisitions at the same orbital position (i.e., zeros baseline distance in between), which results in a Flattened phase $`\varphi_{\text{Flattended}\_\text{SLC}}`$, independent of the local topography. -The phase subtraction could be performed by using a motion compensation approach (Zebker et al., 2010) or directly on the SLC data. Then the geometrical correction is performed on the Flattened SLC, which results in a **[GSLC]** product. -# -**[GSLC]** can also be saved as a **[NRB]** product by including the Flattened Phase per-pixel data (item 3.7) as follows: +The phase subtraction could be performed by using a motion compensation approach (Zebker et al., 2010) or directly on the SLC data. Then the geometrical correction is performed on the Flattened SLC, which results in a **\[GSLC]** product. -$$`\text{NRB:} \quad \gamma_T^0 = |GSLC|^2 `$$ +**\[GSLC]** can also be saved as a **\[NRB]** product by including the Flattened Phase per-pixel data (item 3.7) as follows: -$$`\text{Flattended Phase:} \quad \varphi_{\text{Flattended}} = \arg (GSLC) `$$ +$$\text{NRB:} \quad \gamma_T^0 = |GSLC|^2 $$ -For **[POL]** product, the Flattened phase needs also to be subtracted from the complex number phase of the off-diagonal elements of the covariance matrix. +$$\text{Flattended Phase:} \quad \varphi_{\text{Flattended}} = \arg (GSLC) $$ -Demonstration: +For **\[POL]** product, the Flattened phase needs also to be subtracted from the complex number phase of the off-diagonal elements of the covariance matrix. -From CEOS-ARD flattened SAR products, InSAR processing can be easily performed without dealing with topographic features and orbital sensor position, as for example with two **[GSLC]** products +Demonstration: -$$` \varphi_{\text{Flattened}\textunderscore\text{GSLC}\textunderscore1} = \varphi_{\text{SLC}\textunderscore1} - \Delta\varphi_{\text{Topo}\textunderscore\text{OrbRef}-1} = \varphi_{\text{SLC}\textunderscore1} - \varphi_{\text{DEM}\textunderscore\text{OrbRef}} - \varphi_{\text{DEM}\textunderscore\text{SLC}\textunderscore1}`$$ +From CEOS-ARD flattened SAR products, InSAR processing can be easily performed without dealing with topographic features and orbital sensor position, as for example with two **\[GSLC]** products -$$` \tag{Eq. A1.4} \varphi_{\text{Flattened}\textunderscore\text{GSLC}\textunderscore2} = \varphi_{\text{SLC}\textunderscore2} - \Delta\varphi_{\text{Topo}\textunderscore\text{OrbRef}-2} = \varphi_{\text{SLC}\textunderscore2} - \varphi_{\text{DEM}\textunderscore\text{OrbRef}} - \varphi_{\text{DEM}\textunderscore\text{SLC}\textunderscore2}`$$ +$$ \varphi_{\text{Flattened}\_\text{GSLC}\_1} = \varphi_{\text{SLC}\_1} - \Delta\varphi_{\text{Topo}\_\text{OrbRef}-1} = \varphi_{\text{SLC}\_1} - \varphi_{\text{DEM}\_\text{OrbRef}} - \varphi_{\text{DEM}\_\text{SLC}\_1}$$ +$$ \tag{Eq. A1.4} \varphi_{\text{Flattened}\_\text{GSLC}\_2} = \varphi_{\text{SLC}\_2} - \Delta\varphi_{\text{Topo}\_\text{OrbRef}-2} = \varphi_{\text{SLC}\_2} - \varphi_{\text{DEM}\_\text{OrbRef}} - \varphi_{\text{DEM}\_\text{SLC}\_2}$$ The differential phase is -$$` \tag{Eq. A1.5} \Delta \varphi_{\text{CARD}\textunderscore1-\text{CARD}\textunderscore2} = \varphi_{\text{Flattened}\textunderscore\text{GSLC}\textunderscore1} - \varphi_{\text{Flattened}\textunderscore\text{GSLC}\textunderscore2} `$$ +$$ \tag{Eq. A1.5} \Delta \varphi_{\text{CARD}\_1-\text{CARD}\_2} = \varphi_{\text{Flattened}\_\text{GSLC}\_1} - \varphi_{\text{Flattened}\_\text{GSLC}\_2} $$ Which can be expanded using (Eq. A1.3) -$$` \tag{Eq. A1.6} \Delta \varphi_{\text{CARD}\textunderscore1-\text{CARD}\textunderscore2} = (\varphi_{\text{SLC}\textunderscore1} - \varphi_{\text{DEM}\textunderscore\text{OrbRef}} - \varphi_{\text{DEM}\textunderscore\text{SLC}\textunderscore1}) - (\varphi_{\text{SLC}\textunderscore2} - \varphi_{\text{DEM}\textunderscore\text{OrbRef}} - \varphi_{\text{DEM}\textunderscore\text{SLC}\textunderscore2}) `$$ - -$$` \tag{EQ. A1.7} \Delta \varphi_{\text{CARD}\textunderscore1-\text{CARD}\textunderscore2} = (\varphi_{\text{SLC}\textunderscore1} - \varphi_{\text{SLC}\textunderscore2}) - (\varphi_{\text{DEM}\textunderscore\text{SLC}\textunderscore1}) - \varphi_{\text{DEM}\textunderscore\text{SLC}\textunderscore2}) `$$ +$$ \tag{Eq. A1.6} \Delta \varphi_{\text{CARD}\_1-\text{CARD}\_2} = (\varphi_{\text{SLC}\_1} - \varphi_{\text{DEM}\_\text{OrbRef}} - \varphi_{\text{DEM}\_\text{SLC}\_1}) - (\varphi_{\text{SLC}\_2} - \varphi_{\text{DEM}\_\text{OrbRef}} - \varphi_{\text{DEM}\_\text{SLC}\_2}) $$ -$$` \tag{EQ. A1.8} \Delta \varphi_{\text{CARD}\textunderscore1-\text{CARD}\textunderscore2} = \Delta\varphi_{\text{SLC}\textunderscore1-\text{SLC}\textunderscore2} - \Delta\varphi_{\text{Topo}\textunderscore1-2} `$$ +$$ \tag{EQ. A1.7} \Delta \varphi_{\text{CARD}\_1-\text{CARD}\_2} = (\varphi_{\text{SLC}\_1} - \varphi_{\text{SLC}\_2}) - (\varphi_{\text{DEM}\_\text{SLC}\_1}) - \varphi_{\text{DEM}\_\text{SLC}\_2}) $$ -Where $`\Delta\varphi_{\text{SLC}\textunderscore1-\text{SLC}\textunderscore2}`$ can be express as Eq. A1.1, which gives +$$ \tag{EQ. A1.8} \Delta \varphi_{\text{CARD}\_1-\text{CARD}\_2} = \Delta\varphi_{\text{SLC}\_1-\text{SLC}\_2} - \Delta\varphi_{\text{Topo}\_1-2} $$ -$$` \tag{EQ. A1.9} \Delta \varphi_{\text{CARD}\textunderscore1-\text{CARD}\textunderscore2} = (\Delta \varphi_{\text{Topo}\textunderscore1-2} + \Delta \varphi_{\text{Disp}\textunderscore1-2} + \Delta \varphi_{\text{Noise}\textunderscore1-2}) - \Delta\varphi_{\text{Topo}\textunderscore1-2} `$$ +Where $`\Delta\varphi_{\text{SLC}\_1-\text{SLC}\_2}`$ can be express as Eq. A1.1, which gives +$$ \tag{EQ. A1.9} \Delta \varphi_{\text{CARD}\_1-\text{CARD}\_2} = (\Delta \varphi_{\text{Topo}\_1-2} + \Delta \varphi_{\text{Disp}\_1-2} + \Delta \varphi_{\text{Noise}\_1-2}) - \Delta\varphi_{\text{Topo}\_1-2} $$ Consequently, the differential phase of two CEOS-ARD products doesn’t contain a topographic phase and is already unwrapped (at least over stable areas). It is only function of the surface displacement and of the noise term. Depending on the reference DEM and the satellite orbital state vector accuracies, some residual topographic phase could be present. Atmospheric (item 2.15) and ionospheric (item 2.16) phase corrections could be performed during the production of CEOS-ARD products, which reduces the differential phase noise in an InSAR analysis. -$$` \tag{EQ. A1.9} \Delta \varphi_{\text{CARD}\textunderscore1-\text{CARD}\textunderscore2} = \Delta \varphi_{\text{Disp}\textunderscore1-2} + \Delta \varphi_{\text{Noise}\textunderscore1-2})`$$ - - - +$$ \tag{EQ. A1.9} \Delta \varphi_{\text{CARD}\_1-\text{CARD}\_2} = \Delta \varphi_{\text{Disp}\_1-2} + \Delta \varphi_{\text{Noise}\_1-2})$$ diff --git a/Specifications/Synthetic-Aperture-Radar/annex-2-polarimetric-radar.md b/Specifications/Synthetic-Aperture-Radar/annex-2-polarimetric-radar.md index 2a6fd34..f1620d5 100644 --- a/Specifications/Synthetic-Aperture-Radar/annex-2-polarimetric-radar.md +++ b/Specifications/Synthetic-Aperture-Radar/annex-2-polarimetric-radar.md @@ -1,6 +1,8 @@ - -# Annex 2: Polarimetric Radar [POL] -## A2.1: Normalised Covariance Matrices (CovMat) + + +## Annex 2: Polarimetric Radar \[POL] + +### A2.1: Normalised Covariance Matrices (CovMat) In order to preserve the inter-channel polarimetric phase and thus the full information content of coherent dual-pol and fully polarimetric data, the covariance matrix is proposed as the data storage format. Covariance matrices are generated from the complex cross product of polarimetric channels, as shown in Eq. A2.1 for fully polarimetric data (C3) and in Eq. A2.2 for dual polarization data (C2). Since these matrices are complex symmetrical, only the upper diagonal elements (bold elements) need to be stored in the ARD database. **Fully polarimetric** @@ -12,127 +14,116 @@ C3 = \begin{bmatrix} VV \cdot HH^* & \sqrt{2} \cdot VV \cdot HV^* & |\mathbf{V}\mathbf{V}|^2 \end{bmatrix} $$ - - - -Where HV = VH, under the reciprocity assumption. | | and \* mean respectively complex modulus and the complex conjugate. +Where HV = VH, under the reciprocity assumption. \| \| and \* mean respectively complex modulus and the complex conjugate. **Dual polarization** - -$$ \text{HH-HV:} \quad C2 = \begin{bmatrix} +$$ +\text{HH-HV:} \quad C2 = \begin{bmatrix} | \mathbf{H} \mathbf{H} |^2 & \mathbf{H}\mathbf{H} \cdot \mathbf{H}\mathbf{V}^* \\ HV \cdot HH^* & |\mathbf{H}\mathbf{V}|^2 \end{bmatrix} $$ -$$ \tag{Eq. A2.2} \text{VV-VH:} \quad C2 = \begin{bmatrix} +$$ +\tag{Eq. A2.2} \text{VV-VH:} \quad C2 = \begin{bmatrix} | \mathbf{V} \mathbf{H} |^2 & \mathbf{V}\mathbf{H} \cdot \mathbf{V}\mathbf{H}^* \\ VH \cdot VH^* & |\mathbf{V}\mathbf{V}|^2 \end{bmatrix} $$ -$$ \text{CH-CV:} \quad C2 = \begin{bmatrix} +$$ +\text{CH-CV:} \quad C2 = \begin{bmatrix} | \mathbf{C} \mathbf{H} |^2 & \mathbf{C}\mathbf{H} \cdot \mathbf{C}\mathbf{V}^* \\ CV \cdot CH^* & |\mathbf{C}\mathbf{V}|^2 \end{bmatrix} $$ - -Where CH and CV refer to dual polarization transmitting a circular polarized signal. [CH, CV] can be replaced by [LH, LV] or [RH, RV] for left (L) or right (R) hand circular transmission respectively, although RCM will offer only right-hand circular transmission. The coherent HH-VV configuration available on TerraSAR-X could also be represented as C2 format. +Where CH and CV refer to dual polarization transmitting a circular polarized signal. \[CH, CV] can be replaced by \[LH, LV] or \[RH, RV] for left (L) or right (R) hand circular transmission respectively, although RCM will offer only right-hand circular transmission. The coherent HH-VV configuration available on TerraSAR-X could also be represented as C2 format. Polarimetric decomposition methods like Yamaguchi et al. (2011) for fully polarimetric, or m-chi (Raney et al., 2012) for compact polarimetric data, can be applied directly on averaged (speckle filtered) C3 and C2 matrices respectively. These decompositions enhance scattering information, bring it to a more comprehensible level to end-users, and raise the performance of thematic classification methodologies. For SAR products that were acquired with single polarization the use of the covariance matrix does not result in superfluous storage requirements, since only the matrix elements that are populated are retained and the diagonal matrix elements are the backscatter intensities. Thus, a single channel intensity product would yield only one matrix element and the storage needs would not change. -In order to ease the data structure and the metadata in between C3 and C2, Eq. A2.1 should be redefined as Eq. A2.3. Users will have to take care of this non-standard representation when applying their polarimetric analytic tools. “< >” means that ARD matrix elements are speckle filtered. Eq. A2.3 is valid both for dual-linear and quad polarization. - -$$ \tag {Eq. A2.3} +In order to ease the data structure and the metadata in between C3 and C2, Eq. A2.1 should be redefined as Eq. A2.3. Users will have to take care of this non-standard representation when applying their polarimetric analytic tools. “\< \>” means that ARD matrix elements are speckle filtered. Eq. A2.3 is valid both for dual-linear and quad polarization. +$$ +\tag {Eq. A2.3} \text{C3 modified:} \quad C3_m = \begin{bmatrix} | \langle \mathbf{H} \mathbf{H} |^2 \rangle & \langle\mathbf{H}\mathbf{H} \cdot \mathbf{H}\mathbf{V}^* \rangle & \langle\mathbf{H}\mathbf{H} \cdot \mathbf{V}\mathbf{V}^* \rangle\\ \langle HV \cdot HH^* \rangle & \langle|\mathbf{H}\mathbf{V}|^2 \rangle & \langle\mathbf{H}\mathbf{V} \cdot \mathbf{V}\mathbf{V}^* \rangle \\ \langle VV \cdot HH^* \rangle& \langle VV \cdot HV^* \rangle & \langle|\mathbf{V}\mathbf{V}|^2 \rangle \end{bmatrix} $$ - Furthermore, for compact polarimetric data, it is recommended to store them, by simple transformation, under the circular-circular basis, since RR and RL polarizations (Eq. A2.4) permit faster and more intuitive RGB visualizations (R=RR, G=RR/(RR+RL), B= RL). - -$$ \tag{Eq. A2.4} +$$ +\tag{Eq. A2.4} \text{CH-CV (C2 circular):} \quad C2_c = \begin{bmatrix} \langle | \mathbf{R} \mathbf{R} |^2 \rangle & \langle\mathbf{R}\mathbf{R} \cdot \mathbf{R}\mathbf{¬}^* \rangle \\ \langle RL \cdot RR^* \rangle & \langle|\mathbf{R}\mathbf{L}|^2\rangle \end{bmatrix} $$ -## A2.2: Polarimetric Radar Decomposition (PRD) -Different methodologies allow decomposition of coherent dual-polarization data or fully polarimetric data to meaningful components summarizing the scattering processing with the interacting media. Decomposition techniques are divided in two categories: Coherent and incoherent. - -1. **Coherent decompositions** express the scattering matrix by the summation of elementary objects of known signature (ex.: a sphere, a diplane, a cylinder, a helix, …). They are used mainly to describe point targets which are coherent. As for examples, coherent PRD could be (but not limited to): - -a. Pauli decomposition (3 layers) -$`|\alpha|^2`$: sphere (odd-bounce interaction) [Intensity] - -$`|\beta|^2`$: 0o diplane (even-bounce interaction) [Intensity] - -$`|\gamma|^2`$: 45o diplane (volumetric interaction) [Intensity] - -b. Krogager decomposition (5 layers) (Krogager, 1993) - -$`|\kappa_\sigma|^2`$ : sphere (odd-bounce interaction) [Intensity] - -$`|\kappa_\delta|^2`$ : diplane (odd-bounce interaction) [Intensity] - -$`|\kappa_\eta|^2`$ : helix [Intensity] - -$`\theta`$: orientation angle [degrees] - -$`\Phi_s`$: sphere to diplane angle [degrees] - -c. Cameron (nine classes) – non-dimensional layers (Cameron et al., 1996) - -**Table A2.1** - -|**Classes**|**ID**| -| :-: | :-: | -|Trihedral|1| -|Dihedral|2| -|Narrow Dihedral|3| -|Dipole|4| -|Cylinder|5| -|¼ wave|6| -|Right Helix|7| -|Left Helix|8| -|Asymmetrical|9| - - -2. **Incoherent decompositions** describe distributed targets in terms of scattering mechanisms and their diversity. They are generated from averaged Covariance, Coherence or Kennaugh matrices. As for examples, incoherent PRD could be (but not limited to): -a. Based and saved on intensity of scattering mechanisms can be (Freeman and Durden, 1998; Yamaguchi et al., 2011; Raney et al., 2012) - -**Table A2.2** -Level 2b - Layers [Intensity] | Incoherent Decompositions | ||
|---|---|---|---|
| Freeman-Durden | Yamaguchi | m-chi | |
| Odd-bounce (surface/trihedral) | X | X | X |
| Even-bounce (dihedral) | X | X | X |
| Random (volumetric) | X | X | X |
| Helix | X | ||