this adds coreBetterScore() which takes account of tilt and yaw
alignment when comparing cores for lane switching
this ensures we don't switch to a lane that is unaligned due to the
zero error score for unaligned lanes
this allows the EKF core index to be used to select a GPS/baro/mag
instance. This is an alternative to GPS blending that allows EKF lane
switching to be used to select the right combination of GPS and IMU
add logging to XKFS message
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: fix failure to arm with EK3_MAG_CAL = 7
AP_NavEKF3: Fix failure to arm when not using magnetometer
AP_NavEKF3: Reduce yaw drift when EK3_MAG_CAL = 7
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.
this allows for a magnetometer to be used as a fallback yaw source in
flight when using an external yaw source such as a GPS. The
magnetometer bias is learned while the GPS yaw is available and
fallback is only done if the mag yaw and GPS yaw are consistent when
fallback is enabled
This also learns the Z gyro bias until first yaw alignment when
MAG_CAL is EXTERNAL_YAW_FALLBACK. This prevents large gyro bias
building while waiting for GPS lock
Adapted from EKF2 implementation as of commits
3835d2613, e9ed3540f and df4fc0fff
this sets a limit on the difference between the earth field from the
WMM tables and the learned earth field inside the EKF. Setting it to
zero disables the feature. A positive value sets the limit in mGauss.
this moves intermediate variables from being per-core to being common
between cores. This saves memory on systems with more than one core by
avoiding allocating this memory on every core.
This is an alternative to #11717 which moves memory onto the stack. It
doesn't save as much memory as #11717, but avoids creating large stack
frames
this ensures we consistently fly with EKF lane1 if it is healthy at
the point we arm. Otherwise the choice of lane will be a lottery.
This is important as many systems have quite different filtering and
vibration characteristics on their different IMUs. We by default
enable fast sampling only on the first IMU for example, which means
the 2nd and 3rd IMUs are more vulnerable to high freq causing
aliasing.
this fixes an issue in selecting the best lane to change to when we
have 3 or more EKF cores. The bug is that if the current lane is
unhealthy it would always choose the last healthy lane instead of
choosing the lane with the lowest score
