this gives more control over throttle for petrol
helis. H_RSC_POWER_NEGC allows for a asymmetric V-curve, which allows
for less power being put into the head when landing or when sitting on
the ground. That can lead to significantly less vibration and chance
of ground oscillation. A heli not being flown with aerobatics does not
need to use high throttle at negative collective pitch.
The H_RSC_SLEWRATE allows for a maximum throttle slew rate to be
set. Some petrol motors can cut if the throttle is moved too
quickly. We had this happen at a height of 6m when switching from
ALT_HOLD to STABILIZE mode. It also lowers the chance of the blades
skewing in their holders with the sudden change of power when the heli
is disarmed. In general it is a bad idea to do instantaneous large
movements of a IC engine throttle.
Magnetometer bias states will subject to larger errors early in flight before flight motion makes the offsets observable and the state variances reduce.
Adds a check on state variances.
Replaces the parameter check with a check of the actual filter fusion method being used.
Allow different process noise to be set for body (sensor bias) and earth field states.
This allows a stable magnetometer bias estimate to be available at end of flight whilst still allowing for external magnetic anomalies during landing.
Adjust default values to give stable mag bias learning and fast learning of external anomalies.
Automatically use the highest gain consistent with a 5% overshoot to minimise RMS tracking errors.
Provide an alternative correction method for the position and velocity states that allows the user to specify the time-constant. This can be used to fine tune the output observer for for platform specific sensor errors and control loop sensitivity estimation noise.
The toilet bowling check during early flight has been removed. This check caused problems where bad compass calibration was the cause of the toilet bowling and resetting to the compass was a bad option. The handling of simultaneous failed mag and velocity innovations is already handled outside the EKF by the failsafe.
A check for yaw errors due to a ground based magnetic anomaly has been introduced.
The logic for in-flight yaw and magnetic field resets has been cleaned up and variable names improved.
