also allows using ExtNav alt when not using it for XY position
removes redundant and incorrect setting of activeHgtSource from ExtNav
which was always being overwritten by the correct value later in selectHeightForFusion
Clarifies use of EK3_RANGE_USE_HGT and EK3_ALT_SOURCE parameters to control range finder use.
Setting EK3_RNG_USE_HGT to a positive number to enable automatic switching between the primary height source (baro or GPS) and range finder should be disabled if any primary height source other than Baro or GPS is selected via the EK3_ALT_SOURCE parameter.
AP_NavEKF3: Add emergency yaw reset using a Gussian Sum Filter estimate
AP_NavEKF3: Reduce default minimum GPS velocity noise for Copters
Enables fail-safe to be set with more sensitivity and improves tracking accuracy.
Origin values were set using typical GPS performance for receivers on sale 6 years ago. Receiver performance has improved since then.
AP_NavEKF3: Prevent constant mag anomaly yaw resets
Prevents constant magnetic anomaly induced resets that can be triggered when flying with vehicle generated magnetic interference.
Allows for two resets per takeoff. Allowance for two resets is required, becasue a large ground based magnetic yaw anomaly can cause a sufficiently large yaw innovation that two resets in close succession are required.
AP_NavEKF3: Add option to fly without magnetometer
AP_NavEKF3: Rework emergency yaw reset logic
Use a separate external accessor function to request the yaw reset.
Allow reset requests to remain active for a defined period of time.
Tidy up reset function to split out accuracy check.
AP_NavEKF3: Fix vulnerability to lane switch race condition
Prevents the situation where a lane switch results in a lane being selected that does not have the correct yaw. This can occur if the primary lane becomes unhealthy before the external failsafe monitor has time to react.
AP_NavEKF3: Fix EKF_MAG_CAL = 6 behaviours
Fix bug causing the yaw alignment to be performed at startup before the GSF had a valid estimate.
Fix bug causing emergency yaw message to be output for a normal reset.
Fix vulnerability to reported negative yaw variance.
Remove duplicate timer checks.
AP_NavEKF3: Update EK3_MAG_CAL documentation
AP_NavEKF3: Relax yaw gyro bias convergence check when not using mag
AP_NavEKF3: Reduce yaw drift in hover with no yaw sensor
Uses the GSF yaw estimate if available which is better than the EKF's own yaw when no yaw sensor is available.
when GPS primary switches we were using a position which had not been
corrected for antenna offset. This was used for calculating the reset
for sensor change.
This fixes that (trivial fix) and also fixes a similar issue on
position reset
when on the ground without a position source we would disable the
innovation gate for the barometer. This meant that a single (or small
number of) really bad baro readings would be fused into the EKF,
causing it to destabilise
Fixes#11903
