mc_pos_control: operate in local frame

[DrTon]

• Critical fixes for map_projection_XXX functions, use struct to store reference point, no global variables anymore
• Allow using EASY mode with standalone PX4FLOW

Not tested.
Not for merging yet.

[DrTon]

After fixing some bugs mission works in HIL!

[DrTon]

Tested in flight (with GPS, without PX4FLOW).

TODO:

• use home position as reference

[LorenzMeier]

@DrTon Does this mean it could be merged as is as the home position as reference is more of a future feature thing?

[DrTon]

I want also to do more cleanup:

• remove 'valid' flags from global position (you are right, I already had problems with non-valid topic published)
• now baro_alt is not used anymore by mpc, so can be moved to local_position topic
• handle in-air reference position changes

[DrTon]

Set home on arming. position_estimator_inav changes local position reference together with home position.

[LorenzMeier]

@DrTon Does this include a check if the arming is due to an in-air restart?

[LorenzMeier]

@DrTon Sorry, I forgot: If you want me to look at how to set the conditions for detecting the in-air restart, please let me know.

[DrTon]

@DrTon Does this include a check if the arming is due to an in-air restart?

Not yet.

@DrTon Sorry, I forgot: If you want me to look at how to set the conditions for detecting the in-air restart, please let me know.

Yes, it would be good. But the most we can do is just keep home position undefined instead of setting current.