GPS Fix estimation (dead reconing, RTH without GPS fix) for fixed wing

[RomanLut]

GPS Fix estimation (dead reconing, RTH without GPS fix) for fixed wing

Video demonstration

There is possibility to allow plane to estimate it's position when GPS fix is lost.
The main purpose is RTH without GPS.
It works on fixed wing only.

Up-to-date description:
https://github.com/RomanLut/inav/blob/submit-gps-fix-estimation/docs/GPS_fix_estimation.md

Requires configurator change:
iNavFlight/inav-configurator#1669

[RomanLut]

Tested in simulator only :(

[JulioCesarMatias]

I think some problems occurred during your push... Because you have several files modified, with the HIL mode included... You have 2 options:

1 - Close this PR and open a new one with only the modifications of this new recurse.

2 - Sync the branch of this PR with the Master, and delete the files from the HIL mode.

As there were many files changed, I myself couldn't read the algorithm and understand what you changed to add the feature (maybe it's even laziness on my part)

[JulioCesarMatias]

yeah... this PR is hard to analyze now, I'll leave it for the future

[JulioCesarMatias]

the "dead-reckoning" part of the coordinates, wind and fuselage velocity also exists in a new AHRS that I'm working on bringing to iNav... Glad we had the same idea ^^

[JulioCesarMatias]

the "BOXGPSOFF" option should only be kept during testing before that one day it is approved to merge... It will be good help for Dev's testing... When this feature has a final version, I recommend removing the option to force the GPS failure (I don't think you want users bothering you and saying that your algorithm crashes their planes)

[DzikuVx]

@RomanLut please update docs and resolve conflicts please

[RomanLut]

@RomanLut please update docs and resolve conflicts please

done.

[breadoven]

Does the wind estimator only seem to work if you fly in circles ? This is typically how wind estimators work with software for paragliders/hang gliders etc, either rely on flying in circles (thermaling) or flying in zig zags was another option.

[RomanLut]

Zigzag should work too.

Wind estimator does estimation when attititude changes by ~10 degrees. Then estimated wind vector is updated with 5% of computed value. ~36 estimations in circle is enough to get good estimation.

https://drive.google.com/file/d/0ByvTkVQo3tqXVzBYQUZicUNvbEE/view?resourcekey=0-s-7v3PgOUrZt7fI6JNlu-Q

[shota3527]

@RomanLut

Cruise airspeed is specified in m/s.

To convert km/h to m/s, multiply by 27.77.

Example: 100 km/h = 100 * 27.77 = 2777 m/s

is this cm/s or m/s ?

[RomanLut]

is this cm/s or m/s ?

You are right, it should be cm/s, updated documentation. Thanks.

[b14ckyy]

Hi @RomanLut
I want to real flight test this feature in the next days. But it has conflicts. Can you solve them so I can put it in a test build?

[RomanLut]

@RomanLut I'm moving this to INAV 7. But I'd like to merge whenever you say it's safe to merge. So, is it safe to merge?

Feature is ready to merge now

[konstkarapan]

Sounds very interesting. Could this be implemented for multirotors as well?

[DangerD1024]

Any workaround with spoofing?

[DzikuVx]

@RomanLut thi somehow got below my radar :( Can you resolve conflicts and then we will schedule for 7.1?

[RomanLut]

@RomanLut thi somehow got below my radar :( Can you resolve conflicts and then we will schedule for 7.1?

Resolved

[DzikuVx]

@RomanLut damn, we have more conflicts now....

[RomanLut]

@RomanLut damn, we have more conflicts now....

@DzikuVx Resolved

[bakwc]

Cool!

[RomanLut]

@DzikuVx please also merge https://github.com/iNavFlight/inav-configurator/pull/1669/files