Navigator: land: fix when flying without global position estimate

[sfuhrer]

Solved Problem

Fixes #21524
Fixes #23773
Proposes a partial alternative to #23839

Land without global position estimate (e.g. GNSS-denied without manually initialized position) was broken since efc8c16. Instead of landing at the current spot it flew to (0/0).

Solution

Set lat/lon fields of triplet to NAN if global position is not valid. Further I disable the breaking distance calculation in this case, as it's requiring global position. Will be anyway removed from Navigator with #23678.

Changelog Entry

For release notes:

Bugfix: Navigator: land: fix when flying without global position estimate

Alternatives

Test coverage

SITL tested.

Context

Land without global position only works with MC vehicles, FW requires global position.

[AlexisTM]

I tested it in simulation and it properly lands in position without a GPS

[ptrindade96]

Hi @sfuhrer. It would be nice if you could backport this to v1.14, since the same issue occurs with that version.

You can take a look in this discussion.

[DronecodeBot]

This pull request has been mentioned on Discussion Forum for PX4, Pixhawk, QGroundControl, MAVSDK, MAVLink. There might be relevant details there:

https://discuss.px4.io/t/auto-land-going-to-the-origin-with-optical-flow/40767/3

[MaEtUgR]

Sorry I blew up your pr with the last naming refactoring commit but the breaking functions haunted me 😇 Feel free to change it again or I can also make a separate pr.

[MaEtUgR]

It would be nice if you could backport this to v1.14, since the same issue occurs with that version.

We usually only do point releases on the last stable but it's maybe worth a backport if people are struggling...

[sfuhrer]

Hi @sfuhrer. It would be nice if you could backport this to v1.14, since the same issue occurs with that version.

You can take a look in this discussion.

I don't think there are any more 1.14 releases planned, as we now have 1.15 out already. I will thus port it to the 1.15 branch.

[duguguang]

how about the takeoff command?

[ptrindade96]

Hi @sfuhrer. It would be nice if you could backport this to v1.14, since the same issue occurs with that version.
You can take a look in this discussion.

I don't think there are any more 1.14 releases planned, as we now have 1.15 out already. I will thus port it to the 1.15 branch.

That's ok, at least for me it makes no difference. Thanks for your help Silvan.

[sfuhrer]

how about the takeoff command?

Good point. I've re-opened #21524.

[DronecodeBot]

This pull request has been mentioned on Discussion Forum for PX4, Pixhawk, QGroundControl, MAVSDK, MAVLink. There might be relevant details there:

https://discuss.px4.io/t/land-mode-always-land-to-x-0-y-0/33742/6