oculus_sonar_driver

ROS nodes that use liboculus to interface with a Blueprint Subsea Oculus sonar sonar and publish to ROS topics. Currently runs on ROS Melodic and Noetic.

At present we have only tested with the Oculus M1200d sonar.

Contents

This package defines the oculus_sonar/driver nodelet that interfaces with the sonar over ethernet and publishes acoustic_msgs::SonarImage and apl_msgs::RawData messages.

The package also builds a conventional node oculus_driver which is a trivial wrapper around a oculus_sonar/driver nodelet.

** Note that to visualize the data (as a ROS Image) you need to run a sonar_image_proc/draw_sonar node/nodelet. The default_ros.launch launchfile will launch this node if draw_sonar:=true is passed to it.

Installation

1. Either:
   1. Use vcstool:
      1. Clone this repo to <catkin_ws>/src
      2. cd <catkin_src>
      3. vcs import --input oculus_sonar_driver/oculus_sonar_driver.rosinstall
   2. Or install dependencies manually. Clone liboculus, hydrographic_msgs and g3log_ros to <catkin_ws>/src
2. Use rosdep to install other dependencies
   1. cd <catkin_ws>
   2. rosdep install --from-paths src -i
3. Run catkin_make or catkin build from <catkin_ws>
4. Run source ./devel/setup.bash from <catkin_ws>

Usage

Running the command roslaunch oculus_sonar_driver default_ros.launch will start the sonar driver. See the comments in default_ros.launch to set sonar parameters at startup. Sonar params can also be set through dynamic reconfigure (below).

dynamic_reconfigure

The sonar params can be modified on the fly using dynamic reconfigure. The launchfile default_ros.launch starts the nodes in a nodelet manager /nodelet_manager to the commands are:

$ rosrun dynamic_reconfigure dynparam get /nodelet_manager           
{'send_range_as_meters': True, 'send_gain': True, 'send_simple_return': True, 'gain_assistance': False, 'all_beams': True, 'num_beams': 1, 'gamma': 127, 'ping_rate': 0, 'data_size': 0, 'freq_mode': 2, 'range': 2.0, 'gain': 50.0, 'groups': {'id': 0, 'parent': 0, 'name': 'Default', 'type': '', 'state': True, 'groups': {}, 'parameters': {}, 'send_range_as_meters': True, 'send_gain': True, 'send_simple_return': True, 'gain_assistance': False, 'num_beams': 1, 'all_beams': True, 'range': 2.0, 'gain': 50.0, 'gamma': 127, 'ping_rate': 0, 'data_size': 0, 'freq_mode': 2}}

For example, for 32-bit mode:

$ rosrun dynamic_reconfigure dynparam set /nodelet_manager data_size 2

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A note about sonar resolution

(This is inferred from experimental data, it's not from Blueprint)

The sonar appears to have a fixed maximum number of range bins, approx 720. It also has fixed quantized range resolutions: ~2.8mm, ~5.6mm, etc. So the number of range bins N present in data at a given range R in meters is:

N = R / (2^k * 2.8mm)  minimizing k s.t. N <= 720

This means, for example:

Range (m)	Bins	Resolution
2.0	709	2.8mm
2.02	720	2.8mm
3	532	5.6mm
4	709	5.6mm
4.065	720	5.6mm
5	443	11.2mm
6	532	11.2mm

etc. This effect seems to be invariant of 256 v 512 beams, and 8/16/32 bit data. Haven't tested in the lower frequency mode

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License

This repository is covered by the BSD 3-Clause License.