Flying aerobatics with Trad Heli has shown that the divergence check can be false triggered when large magnetometer errors and GPS dropouts are present.
This can also happen with multi rotors if large yaw rates are present.
This was an unintended consequence of the ekfsmoothing patch which improved filter stability during high rate manoeuvres, but made the divergence test more sensitive.
This patch reduces the level of 5Hz and 10Hz 'pulsing' heard in motors due to GPS and altimeter fusion which cause a small 5Hz and 10Hz ripple on the output under some conditions. Attitude, velocity and position state corrections from GPS, altimeter and magnetometer measurements are applied incrementally in the interval from receiving the measurement to the predicted time of receipt of the next measurement. Averaging of attitude state corrections is not performed during periods of rapid rotation.
Time stamps are now explicitly initialised to the current IMU time to avoid unwanted activation of timeout logic on filter start and various calls to the hal.scheduler->millis() object have been consolidated.
This catches the case where the vehicle lands but the user doesn't
immediately put the throttle to zero. Before this check it would
continue to attempt to hold it's
This check is redundant now that we have a check within the arm_check()
function.
Removing this check does raise a slight danger that someone could raise
the throttle after arming but before the gyro and baro calibration has
completed but the delay has been greatly shortened from what it once was
so there is much less danger that someone could approach the vehicle
during the short arming delay.
Copter does not yet rely on the terrain data (it's for informational
purposes only) so we will temporarily disable the failure flags to the
GCS to avoid support calls
Randy Mackay
priseborough
Craig Elder
Jonathan Challinger
Andrew Tridgell
Kristian Klausen
Brandon Basso