[Draft] {Sponsored by Intelliterra} Sets OPEN_DRONE_ID_LOCATION status to emergency on MAV_CMD

[jnomikos]

Solved Problem

The GCS Operator is unable to manually set the OPEN_DRONE_ID_LOCATION status to emergency. This change adds a MAVLink command that I added in this PR here and sets the OPEN_DRONE_ID_LOCATION's status to emergency when the command is received.

This change also allows the "Declare Emergency" button in QGC to work.

According to the accepted MOC ASTM docs, specifically F358

"7.7 Emergency Status Indicator:
7.7.1 For standard RID, the emergency status indicator shall
be satisfied using either (or both) of the following methods:

F3586 − 22
7.7.1.1 The system shall provide a mechanism for the
operator to manually assert the emergency status and document
this function in the user instructions. If a manual assert
mechanism is used, it shall be available to use at the operator’s
discretion.

7.7.1.2 The system shall automatically assert the emergency
status at least under the two following conditions:
(1) UAS unable to recover from an uncontrolled descent.
(2) UAS unable to recover from loss of control of the flight
trajectory."

This change is targeting specifically 7.7.1.1.

Context

Associated PRs can be found here:
mavlink/mavlink#2027
mavlink/qgroundcontrol#10770

[hamishwillee]

@dagar We discussed this in the MAVLink dev call and PR mavlink/mavlink#2027 (comment)

The requirement for a user to be able to directly and explicitly set the emergency status to be published is considered optional - ArduPilot for example do not do this, but do implement setting the emergency from vehicle emergency status (and they have got approval for vehicles for FAA).

We're not opposed to this approach (modulo rename of the message) but we don't particularly see the need for the use case. Upshot, whether MAVLink takes the message depends largely on whether this feature and PR is considered worth the cost and you choose to merge this.

[dirksavage88]

Looks good. @jnomikos did you test this out on an actual RID module and test the manual emergency button? Maybe some screen snips of it would be good along with the vehicle status in the mavlink console

[jnomikos]

Looks good. @jnomikos did you test this out on an actual RID module and test the manual emergency button? Maybe some screen snips of it would be good along with the vehicle status in the mavlink console

At the time, I did test with a rid module and a test build of QGC triggering the emergency and it did successfully go into emergency state