when using a vision position system, the user may have vision derived
GPS data coming in using GPS_INPUT msgs. We should not fuse these when
EK2_GPS_TYPE=3 as we end up fusing both vision data and GPS data,
which does not work with the current EK2 code
This change makes it possible to run EK2 and EK3 in parallel in a
Vicon, wityh EK2 using VISION_POSITION_ESTIMATE data and EK3 using
GPS_INPUT (with yaw) data.
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
this prevents the EKF origin on different cores from being initialised
to different values. A common value is stored in the frontend and used
by a core if it doesn't have an origin
this forces the EKF origin to the GPS alt on a height datum reset if
we have GPS lock. If we don't do this then the reported AMSL alt will
drift over time away from the GPS alt when we reset while on the
ground
this allows us to learn the gyro biases each lane would need if it had
to switch to another gyro due to a sensor failure. This prevents a
sudden change in gyro bias on IMU failure
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 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 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
when we had 3 compasses the lack of the 'break' meant when we switched
compass in flight we would always switch back instantly to the one
that we had just rejected.
This avoids creating two pointers of different types to the same memory.
Having two pointers to the same memory can lead to the compiler
optimising code such that a write to one pointer is rearranged to be
either before or after a read from the other pointer depending on which
is deemed faster - not a good outcome.
See discussion here:
https://github.com/ArduPilot/ardupilot/issues/7331
we were getting some uninitialised variables. While it only showed up in
AP_SbusOut, it means we can't be sure it won't happen on other objects,
so safest to remove the approach
Thanks to assistance from Lucas, Peter and Francisco
Toggling between alt sources in flight using the parameter can have unpredictable effects due to the various height offsets and the possibility that the data source may be unavailable.
Previous default was to apply in-flight height origin changes to local position instead of to reported origin height. This caused problems with copters that took off before getting GPS lock.
Fix rounding error bug preventing state from updating after initial convergence.
Decouple GPS reference height from published EKf origin height.
Add bitmask parameter to control update and publishing of GPS reference height.
this changes the stragegy for load levelling between EKF cores so it
works between EK2 and EK3, and with future estimators as well.
It allows us to run EK3 and EK2 at the same time with good scheduling
performance
If the GPS receiver selection changes and we are using GPS for height, the
vertical position will be reset to the new GPS height measurement.
correct output observer history when doing a GPS height reset
Fixes a bug that allows the last reported reset time to to wind back and an out of date reset delta to be reported if a switch to a core that has previously been reset occurs.
Allows multiple consumers provided they access on the same frame.
Fixes a bug that allows the last reported reset time to to wind back and an out of date reset delta to be reported if a switch to a core that has previously been reset occurs.
Allows multiple consumers provided they access on the same frame.
Fixes a bug that allows the last reported reset time to to wind back and an out of date reset delta to be reported if a switch to a core that has previously been reset occurs.
Allows multiple consumers provided they access on the same frame
1) Do not switch to a core until its states have been updated.
2) Distinguish between mandated switches required for health failure and optional switches required due to innovation checks failing.
3) Apply hyseresis to innovation check levels
RC_Channel: To nullptr from NULL.
AC_Fence: To nullptr from NULL.
AC_Avoidance: To nullptr from NULL.
AC_PrecLand: To nullptr from NULL.
DataFlash: To nullptr from NULL.
SITL: To nullptr from NULL.
GCS_MAVLink: To nullptr from NULL.
DataFlash: To nullptr from NULL.
AP_Compass: To nullptr from NULL.
Global: To nullptr from NULL.
Global: To nullptr from NULL.
This can improve position hold performance where it is not practical to have the IMU located at the centroid.
Although this enables the effect of IMU position offsets to be corrected, users will still need to be instructed to place the IMU as close to the vehicle c.g. as practical as correcting for large offsets makes the velocity estimates noisy.
Correction requires the body rates averaged across the flow sensor sampling interval. This data has been added to the sensor buffer.
The body rate data from the flow sensor driver does not contain the Z component, so an equivalent value sampled from the navigation IMU has been used instead.
The variable omegaAcrossFlowTime has been moved out of the class and into the only function that uses it.
A specialised takeoff check is now always performed when we receive new flow data as the default behaviour is to try and use flow data whenever it is received, rather than limit its use to a use to a flow-only mode of operation that had to be selected via user parameter.
Enables simultaneous use of GPS and optical flow data with automatic fallback to relative position mode if GPS is lost and automatic switch-up to absolute position status if GPS gained/re-gained.
Revert "AP_NavEKF2: Fix bug in published yaw reset value found during code review"
commit 175faf1e41.
Revert "AP_NavEKF2: use a struct for all yaw step class variables"
commit 77fad065d1.
Partially revert "AP_NavEKF2: Handle yaw jumps due to core switches"
commit 885bfd1b4e.
The EK2_RNG_USE_HGT parameter sets the height (expressed as a percentage of the maximum range of the range finder as set by the RNGFND_MAX_CM parameter) below which the range finder will be used as the primary height source when the vehicle is moving slowly.
When using a height reference other than GPS, the height datum can drift due to air pressure changes if using baro, or due to terrain height changes if using range finder as the primary height source. To ensure that a consistent height datum is available when switching between altitude sources, the WGS-84 height estimate of the EKF's local positi norigin is updated using a
single state Bayes estimator,
If rngfinder or gps height data is lost whilst being used, there will be a fall-back to baro data.
When switching over to a back up magnetometer, ensure that the earth field estimate are reset. other wise mag earth field estimates due to the previous failed mag could cause data from the new mag to be rejected.
This bug created a race condition whereby if the EKF had to reset the yaw to the GPS ground course to recover from a bad magnetometer, the new heading could be over-written by the bad magnetic heading when the plane reached the height for the scheduled reset.
If the GPS receiver was disconnected and no data received, then then the gpsGoodToAlign check did not get a chance to run and becasue it was previously true the EKF would switch back into aiding.
This prevents this by ensuring that gpsGoodToAlign defaults to false when the check is not being performed.
An additional check has also been dded to ensure that there is GPS data to fuse before we declare ready to use GPS.
Switching in and out of aiding modes was being performed in more than one place and was using two variables.
The reversion out of GPS mode due to prolonged loss of GPS was not working.
This consolidates the logic and ensures that PV_AidingMode is only changed by the setAidingMode function.
The filter status logic calculations were being repeated every time the get function was called.
The logic is now updated once per filter update step and a separate get function added
If we start GPS aiding before the gyro bias variances have reduced, glitches on the GPS can cause attitude disturbances that degrade flight accuracy during early flight.
Co-variances were being re-zeroed after being set. This meant that the initial declination learning was sensitive to measurement errors which could result in poor initial yaw accuracy.
Fixes bugs that prevented planes being able to reset yaw to GPS to recovery from takeoff with a bad magnetoemter.
1) If the velocity innovation check had not failed by the time the in-air transition occurred, then the yaw reset would not be performed
2) The velocity states were not being reset
3) The non fly-forward vehicle (copter) reset could occur first and effectively lock out the fly-forward vehicle (plane) yaw check.
Remember the mag bias and earth field states learned during flight when the vehicle lands.
This improves performance for vehicles that do multiple flight on one power cycle
Provide consistent overshoot of 5% across a wider range of time constants and prevent selection of larger time constants causing 'ringing' in the position and velocity outputs.
Fixes a problem observed in a flight log where rapid temperature change caused the accel bias to change faster than the EKF could keep up.
This allows the bias to be learned faster but with acceptable level of noise in the estimate
IMU data was being corrected before being used by the co-variance prediction, whereas the delta angles and velocities in the derivation were supposed to be uncorrected.
This patch creates separate variable for the corrected data
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.
Randy Mackay
Michael du Breuil
Peter Barker
Andrew Tridgell
hoangthien94
Siddharth Purohit
Pierre Kancir
Paul Riseborough
Mark Whitehorn
Tom Pittenger
Dr.-Ing. Amilcar do Carmo Lucas
Arjun Vinod
chobits
chobitsfan
murata
priseborough
Samuel Tabor
Lucas De Marchi
Jonathan Challinger
Jacob Walser
Francisco Ferreira
Mathieu OTHACEHE