Mavsdk: mission_raw->mission_changed not received on mission clear all

[Jonsen94]

If a mission is deleted from the drone no mission_changed event is triggered if it's deleted using the MAV_MISSION_TYPE_ALL-type. As can be seen in [0] the MAV_MISSION_TYPE type is checked. If it is MAV_MISSION_TYPE_ALL no mission_changed event will be triggered despite the mission changed (was deleted).

[0] https://github.com/mavlink/MAVSDK/blob/2e95299c656b06a46cc9594b71a169cb6095f985/src/plugins/mission_raw/mission_raw_impl.cpp#L63-L65

[JonasVautherin]

Thanks for reporting! Would you be willing to open a pull request to fix this?

[Jonsen94]

Sure, just give me some days.

[Jonsen94]

Might be related. I Just wanted to open a bug report for the python mission_changed subscription not working. Looks like it has a related problem. QGC seems to upload missions with mission type 2 (MAV_MISSION_TYPE_RALLY) which also does not trigger a mission changed event.

Also in case of deleting a QGC mission the result type is 2. I guess this is a design choice if you want to trigger an event in any of the cases. I would suggest doing so as it is a mission in every case? At least MAVLINK calls it MissionItems even for the Geo-Fence points.
see MAV_MISSION_TYPE

Still gonna open the python-report and link it so others know about it.

[Jonsen94]

@JonasVautherin : it seems like the problem is even deeper.

As far as I can tell then drone just doesn't sent the MISSION_ACK command to anyone except for QGC.
I even tried running QGC with the same sys-id as mavsdk. QGC reports MISSION_ACK messages with sysid 1 and comp id 190 but the mavsdk does not receive such a packet. It seems like this message alone is not enough to report mission changes, not sure how QGC does it so accurate.

[JonasVautherin]

Can you describe your setup? Is it something like below?

• PX4 running on the drone
• QGC running on the laptop, on udp://:14550
• MAVSDK running on the laptop, on udp://:14540

Can you reproduce the bug with SITL?

[Jonsen94]

I can't test it with a real drone ;)

Its the setup described in https://github.com/mavlink/MAVSDK-Python/issues/244 except for the python part.

Drone is a px4-gazebo setup from https://github.com/PX4/Firmware.git, I am using tag v1.10.2

MAVSDK is udp://:14560
QGC uses whatever its default is

[julianoes]

QGC seems to upload missions with mission type 2 (MAV_MISSION_TYPE_RALLY) which also does not trigger a mission changed event.

This would be expected, because rally points are not technically mission items. And they are not supported with MAVSDK yet, I think.

[Jonsen94]

Feels a bit strange I would say. I mean, it is called "MAV_MISSION_[...]".
Does that mean that the current behavior is the intended one?

If so this should probably be noted somewhere in the documentation. I mean the API endpoint states that it is meant to be used to detect mission uploads from other GC stations and QGC is as far as I know one of the most widely used ones ?

Or could we just add another parameter (mission_type) into the detection which is returned so one knows which kind of "mission" was changed?

[julianoes]

It is called MAV_MISSION_ because it re-uses the mission messages for upload. But the "MISSION_TYPE" is RALLY.

I would say it's the correct implementation but we should add a rally_points_changed() notification for rally points.

[julianoes]

I'm closing this because I think this would need to be fixed as part of a rally points plugin. To me it has not much to do with the mission_raw plugin which only handles MAV_MISSION_TYPE_MISSION for now.

@Jonsen94 feel free to start a PR in https://github.com/mavlink/MAVSDK-Proto if you want to add a rally plugin.