EKF: add fault status bit for clipping

[dagar]

Does this make sense as a fault status bit? We don't necessarily have all the input data logged at full rate so I wanted to capture this somewhere within ecl/EKF status.

[dagar]

Relevant for multi-ekf, where we could switch the primary estimator immediately on clipping rather than waiting for the effects to accumulate in the comparison metrics (eg PX4/PX4-Autopilot#14650 (comment)).

[bresch]

Sounds like a good idea. Since you're already changing the status flags, can you also add _bad_vert_accel_detected in it? https://github.com/PX4/ecl/blob/f666ebb99552eed796e82a20bb60e813d45eee03/EKF/control.cpp#L902

[dagar]

Yes I'll add that as well.

We're already capturing _bad_vert_accel_detected as ekf_solution_status.accel_error, but that entire message seems to only exist for being passed through to Mavlink.

https://github.com/PX4/ecl/blob/dd3ffc419238bfc7d9b7e3be92a178c2cf7756f1/EKF/common.h#L495

http://mavlink.io/en/messages/common.html#ESTIMATOR_STATUS

We should really give this an overall review at some point, including killing off most of the console messages (#909).

[dagar]

Added bad_acc_vert to fault status.

[bresch]

Thanks!