Commit Graph

736 Commits

Author SHA1 Message Date
Andrew Tridgell 411a96b4b3 AP_NavEKF: take at most 30s to accept DCM attitude
velocity noise on the GPS can cause DCM to take a long time to
converge. If it takes longer than 30s then allow EKF to start
2015-05-20 15:22:15 +10:00
Andrew Tridgell 92c4c5cbcf AP_NavEKF: change using_gps threshold to 4s
this means plane will continue to use dead reckoning with GPS 3D lock
for 4s
2015-05-19 20:52:39 +10:00
Paul Riseborough 69ca654194 AP_NavEKF: Update declination when we know our location
This ensures that when we start using GPS, that the EKF will be using the correct declination for that location
If declination is not known it defaults to zero
2015-05-19 20:35:52 +10:00
Paul Riseborough c1c5e3598a AP_NavEKF: Enforce alignment of realigned earth mag field with declination
This prevents bad inertial or GPS data combined with the post takeoff heading alignment check used by plane from resulting in earth field states that have an incorrect declination
2015-05-19 20:35:52 +10:00
Paul Riseborough b1d8805114 AP_NavEKF: Reduce takeoff detection sensitivity
This patch reworks the in-air transition criteria to reduce the likelihood of false positives and to ensure that there will be enough ground speed to make the heading check work reliably.
2015-05-19 20:35:52 +10:00
Andrew Tridgell 6154db5cf8 AP_NavEKF: added using_gps status bit 2015-05-17 21:24:57 +10:00
Tom Pittenger e987173ffb AP_NavEKF: float to double promotion via tan instead of tanf 2015-05-16 08:21:49 +10:00
Paul Riseborough bd91b9727f AP_NavEKF: Add pre-arm check for horizontal inertial errors
This check will declare the EKF as unhealthy if the horizontal position innovations exceed a threshold  before motors are armed.
This will help to prevent a takeoff with bad inertial data caused by bad accel or gyro offsets.
2015-05-15 10:35:25 +09:00
Paul Riseborough cb59570938 AP_NavEKF: Remove bug preventing external selection of optical flow mode 2015-05-09 18:31:18 +10:00
Tom Pittenger 2deb0e08ea AP_NavEKF: replace fabs() with fabsf() 2015-05-09 09:57:27 +10:00
Paul Riseborough a232606fc9 AP_NavEKF: Prevent EKF yaw errors due to fast yaw spins
Prolonged yaw rotations with gyro scale factor errors can cause yaw errors and gyro bias estimation errors to build up to a point where EKF health checks fail.
This patch introduces the following protections:

1) The assumed yaw gyro error is scaled using a filtered yaw rate and an assumed 3% scale factor error (MPU6000 data sheet)
2) When the filtered yaw rate magnitude is greater than 1 rad/sec, the Z gyro bias process noise is zeroed and the state variance set to zero to inhibit modification of the bias state
3) When the filtered yaw rate magnitude is greater than 1 rad/sec, the magnetometer quaternion corrections are scaled by a factor of four to maintain tighter alignment with the compass
2015-05-08 16:47:31 +09:00
Paul Riseborough 08382373f1 AP_NavEKF: Reduce likelihood of in-air switch to GPS with a bad heading
Increases magnetometer weighting on yaw corrections when there there is no other aiding to constrain yaw drift.
Prevents switch to GPS if magnetometer data is failing innovation checks which indicates a bad yaw angle
2015-05-08 16:47:29 +09:00
Jonathan Challinger 142e018a18 AP_NavEKF: fix bug causing takeoff to fail 2015-05-08 09:15:45 +09:00
Andrew Tridgell a140a5e77f AP_NavEKF: revert AP_Math class change 2015-05-05 13:27:07 +10:00
Tom Pittenger 9b53961a7d AP_NavEKF: compiler warnings: float to double 2015-05-05 13:26:52 +10:00
Tom Pittenger 3276eec30e AP_NavEKF: compiler warnings: apply is_zero(float) or is_equal(float) 2015-05-05 13:26:52 +10:00
Andrew Tridgell c4d6f9d040 AP_NavEKF: fix for HAL_SITL rename 2015-05-05 09:45:55 +10:00
Andrew Tridgell ce0a863d01 AP_NavEKF: allow for optimisation of the EKF
disable optimisation when debugging needed
2015-05-05 09:45:53 +10:00
Paul Riseborough be04be9b43 AP_NavEKF: Fix bug preventing home position being set by copter
The interface definition has been modified so that it returns true for a position obtained usin geither the normal inertial navigation calculation, or a raw GPS measurement.
This enables this function to be used to set a home position before flight.
2015-05-02 17:20:21 +09:00
Randy Mackay fb7e75594f AP_NavEKF: replace memset with quaternion.initialise 2015-05-01 16:37:35 +09:00
Randy Mackay c366fbbc96 AP_NavEKF: remove unused haveDeltaAngles 2015-05-01 16:37:33 +09:00
Paul Riseborough b71b8f4bda AP_NavEKF: Always return a NED relative position if possible
If a calculated position is not available, the function will return a value based on raw GPS or last calculation if available, but the status will be set to false to indicate that it cannot be used for control.
2015-05-01 16:37:32 +09:00
Paul Riseborough 20ba1e6b1b AP_NavEKF: Always return a WGS-84 location if possible
If a calculated location is not available, the function will return raw GPS data if available, but the status will be set to false.
2015-05-01 16:37:31 +09:00
Paul Riseborough dd1e0b2f0b AP_NavEKF: Add missing function to return the NED to XYZ quaternion 2015-05-01 16:37:30 +09:00
Paul Riseborough 2c4572eb50 AP_NavEKF: Make ground effect variable names more descriptive 2015-05-01 16:37:29 +09:00
Paul Riseborough 3986851c51 AP_NavEKF: Prevent Z accel bias changing during ground effect takeoff
The inconsistent baro data during ground effect takeoff combined with the larger variances in the Z accel bias state early in flight can cause unwanted changes in bias estimate and therefore changes in height estimation error.
This patch turns of the process noise and state updates for the Z accel bias state when takeoff in ground effect is expected.
2015-05-01 16:37:28 +09:00
Paul Riseborough 2cba60c731 AP_NavEKF: Decouple takeoff ground effect compensation from arm transtion
Thsi fixes a potential bug where the vehicle could land at a lower location without disarming and re-enter ground effect takeoff mode wiht a baro height floor above the current altitude, causing unpredictable height gain
2015-05-01 16:37:27 +09:00
Paul Riseborough c4c0f819b5 AP_NavEKF: Ensure Covariance initialisation uses correct IMU time step 2015-05-01 16:37:26 +09:00
Paul Riseborough 5dc29699ab AP_NavEKF: Publish the INS delta quaternion 2015-05-01 16:37:25 +09:00
Paul Riseborough d273302ce7 AP_NavEKF: Improve rate of accel bias learning before flight 2015-05-01 16:37:24 +09:00
Paul Riseborough 8dc6354a54 AP_NavEKF: Prevent touchdown baro errors tripping height innovation check
Ground effect baro errors can cause a spike in height innovation on disarming if ground effect compensation was used during the landing. This causes a transient AHRS fault message if this innovation is outside the pre-arm check limits.
Resetting the vertical position state to the measured height after disarming prevents this.
2015-05-01 16:37:23 +09:00
Jonathan Challinger 2f38dd1b67 AP_NavEKF: use quaternion functions to apply IMU delta angles 2015-05-01 16:37:22 +09:00
Jonathan Challinger 9c374eb4a8 AP_NavEKF: apply constrained floor to barometer innovation while landing 2015-05-01 16:37:21 +09:00
Jonathan Challinger 3c6446fadd AP_NavEKF: refactor meaHgtAtTakeOff filter 2015-05-01 16:37:20 +09:00
Paul Riseborough 744de74c16 AP_NavEKF: Reduce ground effect baro induced height errors during takeoff 2015-05-01 16:37:19 +09:00
Paul Riseborough 13616d6436 AP_NavEKF: Add takeoff and touchdown expected to reported filter status 2015-05-01 16:37:19 +09:00
Jonathan Challinger 8c92524b8a AP_NavEKF: add takeoffExpected and touchdownExpected 2015-05-01 16:37:18 +09:00
Jonathan Challinger b6b55bf6f2 AP_NavEKF: integrate gravity over correct time period 2015-05-01 16:37:17 +09:00
Jonathan Challinger cb0c424da1 AP_NavEKF: rewrite readIMUData 2015-05-01 16:37:16 +09:00
Andrew Tridgell 514c349060 AP_NavEKF: raise DCM error_rp threshold to 0.05
it was failing on many boards with fixed wing
2015-04-28 14:07:39 +10:00
Randy Mackay fdf226ebc1 AP_NavEKF: include AP_RangeFinder.h 2015-04-24 15:49:11 +09:00
Tom Pittenger a340d13d01 NavEKF: fix compile warning re member init order 2015-04-24 14:14:12 +09:00
Tom Pittenger d6b34209b5 NavEKF: fix compile warnings re float constants 2015-04-24 14:04:02 +09:00
Randy Mackay b05bdd657d AP_NavEKF: getHeightControlLimit modifies height on success 2015-04-24 10:58:05 +09:00
Paul Riseborough cf04600710 AP_NavEKF: Add public function to limit height control during OF nav 2015-04-24 10:57:56 +09:00
Paul Riseborough 68b225de4d AP_NavEKF: Prevent pre-arm baro drift affecting mag field reset height 2015-04-24 10:57:54 +09:00
Paul Riseborough c2e6fdb56c AP_NavEKF: Reduce effect of noisy baro data on baro height offset estimate
This estimate is used to offset baro data if we need to switch across from range finder data due to sensor failure. The previous filter coefficients gave a 0.5 seconds time constant on the offset which was too susceptible to baro noise.
2015-04-24 10:57:51 +09:00
Paul Riseborough fd7fdc1ad9 AP_NavEKF: Remove unnecessary state resets on arm and disarm
Resetting states unnecessarily creates transients due to presence of bias errors
2015-04-24 10:57:49 +09:00
Paul Riseborough 3e67080002 AP_NavEKF: Use GPS vertical velocity observations to estimate Z accel bias 2015-04-24 10:57:47 +09:00
Paul Riseborough e48171ab11 AP_NavEKF: Improve takeoff with optical flow and range data loss
Range finder and optical flow data can drop-out and be reliable very close to ground. these patches enable the takeoff to be more relaibly detected and constrain optical flow navigation drift in the first part of takeoff.
2015-04-24 10:57:45 +09:00
Paul Riseborough 3e061b174e AP_NavEKF: Report unhealthy for all filter faults 2015-04-24 10:57:43 +09:00
Paul Riseborough 6c4c54c2ba AP_NavEKF: Use default on ground range parameter from range finder object 2015-04-24 10:57:41 +09:00
Jonathan Challinger 10476333d8 AP_NavEKF: don't run when previously disarmed and time has slipped 2015-04-24 10:57:39 +09:00
Jonathan Challinger 085faaac6a AP_NavEKF: fix delay detection so that filter properly resets after a delay 2015-04-24 10:57:36 +09:00
Paul Riseborough 1c8e3f9444 AP_NavEKF: Allow EKF to pull data from range finder object 2015-04-24 10:57:01 +09:00
Paul Riseborough 4a5bf0a266 AP_NavEKF: Reduce EKF start time
Makes EKF start conditional on DCM solution tilt error
2015-04-23 20:35:48 +09:00
Arthur Benemann e59c6ddbae AP_SmallEKF: increase start-up time of the SmallEKF 2015-04-21 21:45:51 +09:00
Arthur Benemann 4ad3e786a5 AP_NavEKF: fix initialization of the SmallEKF
The constructor 'states' variable was not being called. To make sure other variables where also zeroed now
2015-04-21 21:45:36 +09:00
Arthur Benemann 1d9beed42f AP_SmallEKF: add function to report if the EKF is stable 2015-04-21 21:45:29 +09:00
Arthur Benemann 7b28bf7d44 AP_NavEKF: Remove small EKF dependency on navigation EKF 2015-04-21 21:45:28 +09:00
Andrew Tridgell 4586de6637 AP_NavEKF: enable optimisation in Linux build
only really need debugging for SITL
2015-04-16 08:36:16 +10:00
Paul Riseborough dffa2e19bf AP_NavEKF: Make copter glitch accel consistent with timeout and radius 2015-04-15 17:32:48 +09:00
Paul Riseborough 5d70854c08 AP_NavEKF: Fix minor bug in calculation of innovation variance
the innovation variance for GPS should be the sum of squares of the state and measurement uncertainty.
2015-04-15 17:32:46 +09:00
Paul Riseborough 1008c6390c AP_NavEKF: Fail absolute position status if GPS repeatedly rejected 2015-04-15 17:32:44 +09:00
Paul Riseborough 77d3798278 AP_NavEKF: Reduce recovery time after a GPS fusion timeout 2015-04-15 17:32:41 +09:00
Paul Riseborough 0852aeab6e AP_NavEKF: Allow raw innovations to be monitored during timeouts 2015-04-15 17:32:39 +09:00
Paul Riseborough d3f4b4a02b AP_NavEKF: Fix name consistency for data check time stamps 2015-04-15 17:32:36 +09:00
Paul Riseborough e79ccf1fcc AP_NavEKF: Fix bug allowing terrain to be above vehicle position
The terrain state and vehicle state need to be compared at the same time horizon.
2015-04-11 15:51:08 +09:00
Paul Riseborough 6d58c63c4c AP_NavEKF: Prevent potential divide by zeros in OF fusion 2015-04-11 15:51:03 +09:00
Paul Riseborough 89142f1c5f AP_NavEKF: Prevent inadvertent use of DCM roll and pitch estimates.
the use of roll and pitch from the AHRS object is bad because that object could be returning estimates from the backup DCM algorithm.
2015-04-11 15:19:05 +09:00
Paul Riseborough 9268024094 AP_NavEKF: Update default parameters for copter optical flow fusion 2015-04-10 11:08:11 +09:00
Paul Riseborough 4fbdab27ff AP_NavEKF: Use range finder for primary hgt ref in opt flow mode
Falls back to baro if range finder is unavailable
Adds parameter enabling user to select which height source (baro or range finder) will be used during optical flow nav.
2015-04-10 11:08:07 +09:00
Paul Riseborough d618c55e2f AP_NavEKF: Improved handling of noisy GPS speed accuracy data 2015-04-10 11:07:34 +09:00
Paul Riseborough e98edaa6cb AP_NavEKF: Return more accurate validity status for height above ground 2015-04-10 11:07:24 +09:00
Paul Riseborough 586e4a7d2b AP_NavEKF: Add Matlab derivations and simulations behind small EKF 2015-04-10 11:07:21 +09:00
Paul Riseborough c57e25142c AP_NavEKF: Update optical flow fusion maths to reduce height errors 2015-04-07 20:51:18 -07:00
myly10 55befdc345 AP_NavEKF: Typo correction for EAS_NOISE description 2015-04-06 15:52:29 -07:00
Paul Riseborough 9b3656e77c AP_NavEKF: Fix bug introduced in Y axis flow fusion 2015-04-05 21:17:20 -07:00
Andrew Tridgell baf292def1 AP_NavEKF: prevent float exception on startup 2015-04-05 09:16:14 -07:00
Paul Riseborough 7fc0f026d2 AP_NavEKF: Fix bug in optical flow innovation variance integrity check
The check allowed negative innovation variances to pass. If this did occur, the filter would diverge.
2015-04-04 17:03:06 -07:00
Andrew Tridgell c1a0375562 AP_NavEKF: prevent divide by zero in EKF logging 2015-04-04 07:09:02 -07:00
Paul Riseborough 10f050c53b AP_NavEKF: Prevent baro drift causing toilet bowling
The magnetic field states are reset once at 1.5 metres and again at 5 metres. This height check was using the height at the first arm event as the reference. In the situation where there is baro drift and extgended time between the first arm event and flight, this can cause the magnetic field state to be reset when on the ground. If this happens when flying off a metallic surface, the resultant heading errors can cause sever toilet bowling.
2015-04-03 15:18:42 -07:00
Paul Riseborough d4c60ca956 AP_NavEKF: Fix bug preventing reset of velocity after OF fusion timeout 2015-04-03 15:18:39 -07:00
Jonathan Challinger 95cd3480ec AP_NavEKF: review all uses of dtIMU and use dtIMUactual where necessary
pair-programmed-with: Paul Riseborough <p_riseborough@live.com.au>
2015-04-03 15:18:09 -07:00
Andrew Tridgell 79b44d3988 AP_NavEKF: initialise gndEffectMode 2015-04-03 15:15:11 -07:00
Andrew Tridgell 3165c43dfe AP_NavEKF: initialise gpsSpdAccuracy 2015-04-03 15:15:11 -07:00
Paul Riseborough 98c32012fa AP_NavEKF: remove accel bias rate limit when disarmed 2015-04-03 15:15:11 -07:00
Paul Riseborough fe76cb4c0b AP_NavEKF : Make initial height variance consistent with baro noise
This makes sense to do because we initialise the state to the instantaneous baro reading
2015-04-03 15:15:11 -07:00
Paul Riseborough a976e9dad2 AP_NavEKF : Fix bug in scaling of initial Z accel bias state variance 2015-04-03 15:15:11 -07:00
Paul Riseborough 92df3adb5e AP_NavEKF : Fix bug in Z accel bias update for IMU1 2015-04-03 15:15:10 -07:00
Paul Riseborough 5d0952ba23 AP_NavEKF: eliminate onGndBaroNoise 2015-04-03 15:15:10 -07:00
Paul Riseborough fafb898341 AP_NavEKF: tuning change to accel bias learning 2015-04-03 15:15:10 -07:00
Paul Riseborough 398accd151 AP_NavEKF: Improve pre-flight ready checking 2015-04-03 15:15:10 -07:00
Paul Riseborough 5c1a226bef AP_NavEKF : Improvements to pre-arm IMU bias estimation 2015-04-03 15:15:10 -07:00
Jonathan Challinger a5924acb3d AP_NavEKF: set dtIMU from ins expected sample rate 2015-04-03 15:15:10 -07:00
Paul Riseborough a1351e73ab AP_NavEKF : Compensate mag bias states for external copass offset changes 2015-04-03 15:15:09 -07:00
Paul Riseborough 14795719f6 AP_NavEKF: Add public function for estimated magnetometer offsets 2015-04-03 15:15:09 -07:00
Paul Riseborough 1c244af3d8 AP_NavEKF: Fix bug affecting in-flight GPS acquisition
This bug caused velocities to be reset to zero
2015-04-03 15:15:09 -07:00
Paul Riseborough b9b6938b1d AP_NavEKF: Add ability to start using GPS in-flight
Improve the quality of the GPS required to set an EKF  origin
Eliminate repeated update of origin height - origin height updates once when EKF origin is set.
Operation in GPS mode is linked to setting of origin
2015-04-03 15:15:09 -07:00
Paul Riseborough 98fa918b84 AP_NavEKF: Add new compass learning option
Enables compass learning to be on continuously for non-position hold operation
2015-04-03 15:15:09 -07:00
Paul Riseborough 961faa59d9 AP_NavEKF: Don't let reported GPS accuracy modify horiz vel data checks 2015-04-03 15:15:08 -07:00
Paul Riseborough a607eb8469 AP_NavEKF: Reduce the GPS glitch tether length from 100 to 50m 2015-04-03 15:15:08 -07:00
Paul Riseborough 496d31ab83 AP_NavEKF: Reduce max time Copters can reject GPS
The maximum time copters can reject GPS has been reduced from 10 to 7 seconds as flight logs have show that inertial dead reckoning with vibration and calibration errors is not good enough to support 10 seconds without aiding.
2015-04-03 15:15:08 -07:00
Paul Riseborough 8c2029d896 AP_NavEKF: Accel bias learning improvements
Speed up pre-flight learning
Smoothen in-flight learning
2015-04-03 15:15:08 -07:00
Paul Riseborough 19d1b3b813 AP_NavEKF: Update EKF origin height whilst disarmed
This patch causes the EKF to update the height of its origin each time it receives a valid GPs message whislt disarmed.
The resultant EKF origin height represents the height of the zero baro alt datum relative to the GPS height datum.
2015-04-03 15:15:08 -07:00
Paul Riseborough 70afcd7e70 AP_NavEKF: Add second stage alignment of yaw and earth field states
Flight tests have shown that the magnetic field distortion associated with flight from steel structures can extend 3m or higher. To counteract this, a second and final yaw and magnetic field alignment has been added which is activated when the height exceeds 5m for the first time.
2015-04-03 15:15:08 -07:00
Paul Riseborough ed9c05cf2a AP_NavEKF: Remove logic used to delay fusion for load levelling
Logic used to delay optical flow and airspeed fusion to prevent it occurring on the same time step as magnetometer fusion has been removed. This is no longer required to efficiency improvements made at the firmware level.
2015-04-03 15:15:07 -07:00
Paul Riseborough c0d23ffc30 AP_NavEKF: Filter accuracy and stability improvements
Improvements in PX4 firmware have reduced the computational load  and mkae the previous practicwe of splitting magnetometer and optical flow fusion across multiple time steps unnecessary and make it possible to perform a covariance prediction prior to fusing data on the same time step. This patch:

1) Ensures that a covariance prediction is always performed prior to fusion of any observation
2) Removes the splitting of magnetometer fusion so that fusion of the X,Y and Z components occurs on the same time time step
3) Removes the splitting of optical flow fusion so that fusion of X and Y components occurs on the same time step
2015-04-03 15:15:07 -07:00
Jonathan Challinger de1f7f5e63 AP_NavEKF: use published delta velocities and delta angles if available 2015-04-03 15:15:07 -07:00
priseborough 3421a320b5 AP_NavEKF: Compensate for ground effect when takeoff or landing expected 2015-04-03 15:15:07 -07:00
Jonathan Challinger 20d92f5f9d AP_NavEKF: floor GPS velocity noise at parameter value for conservatism 2015-04-03 15:15:07 -07:00
priseborough 9a797a5d49 AP_NavEKF: Use GPS reported speed accuracy if available
UBlox receivers report an estimate of the speed accuracy that tests show correlates well to speed glitches. Using this to scale the GPS velocity observation noise will reduce the effect of bad GPS velocity data.
2015-04-03 15:15:06 -07:00
Andrew Tridgell 3289d38339 AP_NavEKF: make the init functions return bool
we need to know if it has initialised successfully
2015-03-28 10:51:38 -07:00
Andrew Tridgell de3f461a55 AP_NavEKF: use compass->last_update_usec() 2015-03-14 12:31:39 +11:00
Randy Mackay 230ca583d1 NavEKF: support sending EKF_STATUS_REPORT 2015-03-12 12:20:00 +09:00
Paul Riseborough 9f552eaa4b AP_NavEKF: Fix bug that resets position to origin when vehicle arms 2015-02-12 12:40:55 +11:00
Paul Riseborough b8d3da3846 AP_NavEKF: Report last known position when vehicle is disarmed 2015-02-12 12:40:55 +11:00
Andrew Tridgell 55041c7a7a AP_NavEKF: prevent division by zero in SmallEKF 2015-02-12 09:02:59 +11:00
Jonathan Challinger 50466848f7 AP_NavEKF: use hal.util soft_armed state 2015-02-11 20:25:11 +11:00
Grant Morphett 4860c84dff AP_NavEKF: Changes to fix the warnings in rover sitl build.
We are starting the process of resolving all the warnings in the
ardupilot builds of all vehicles and platforms.
2015-02-11 18:16:46 +11:00
Paul Riseborough aa94ff629d AP_NavEKF: Prevent bad GPS pre-arming casuing initial position errors
If the vehicle moves significantly or the GPS changes position significantly pre-armed, then the GPS glitch logic was being invoked when the first GPs measurements were fused. This patch resets the position to the GPS when the vehicle arms.
2015-02-03 15:57:10 +09:00
priseborough bc5581d634 AP_NavEKF: Prevent arming delays from failing GPS
Due to the way that gyro calibration is done, the EKF could be effectively not run for up to 30 seconds in extreme cases, making it possible that the GPS would be failed on arming and the copter put into a non-GPS mode.

the longer term solution is to update the gyro calibration so that it does not hold up other processing. the short tyermfix in thsi patch is to look for evidence of a 3D lock in the last received GPS message.
2015-02-03 15:57:09 +09:00
priseborough 2c012c2763 AP_NavEKF: Always check for new GPS data
This fixes a bug that meant that once the EKF had started up in a non-GPS mode, it would no longer read the GPS and therefore would never be able to use GPS again until reset.
2015-02-03 15:57:08 +09:00
Paul Riseborough 925d625ed1 AP_NavEKF: fix bug in small EKF velocity fusion 2015-02-03 09:49:17 +11:00
Paul Riseborough 5f24603ceb AP_NavEKF: Publish small EKF quaternion and gyro bias outputs 2015-02-03 09:49:16 +11:00
Andrew Tridgell 4c8b663200 AP_NavEKF: added initial version of SmallEKF
This will be used for gimbal bias estimations. 

Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2015-02-03 09:49:16 +11:00
Andrew Tridgell 850af14949 AP_NavEKF: raise EKF_POS_GATE and EKF_GLITCH_RAD for planes
This weights GPS position more heavily for planes

Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2015-01-31 21:49:20 +11:00
priseborough 5df733a883 AP_NavEKF: Allow flight transition to optical flow mode if GPS is lost 2015-01-22 14:41:04 +09:00
priseborough 04810c012d AP_NavEKF: Increase flow data valid timeout to handle arming delays
When Copter arms, the AHRS/EKF may not be run for a few hundred msec depending on conditions. This can cause the arming check to fail the optical flow sensor and place the EKF in a constant position mode.
2015-01-22 14:41:01 +09:00
priseborough 073b8e7c43 AP_NavEKF: Always explicitly set required const pos or vel mode when arming
This additional explicit setting of the constPosMode and constVelMode reduces the likelihood of logic errors being introduced in the future as it places the intended setting of these parameters at arming in the one place. the constVelmode and constPosMode only have one set of conditions each that can trigger these modes in flight, so if these modes are true after arming it will be clear that it was the in-flight condition that triggered.
2015-01-22 14:40:59 +09:00
priseborough 9c6dabe1cc AP_NavEKF: Add separate flow default parameters for platform types
Also reduces flow measurement noise default for copter only and increases gate to compensate.
2015-01-22 14:40:57 +09:00
priseborough d2da16e652 AP_NavEKF: Consistently set timeout flags whenever aiding is inhibited
This ensures the position and velocity measurement status will be set as timed out immediately after use of those measurements is inhibited. This will improve the timeliness of filter status reporting.
2015-01-22 14:40:55 +09:00
priseborough 824425625c AP_NavEKF: Update public method used to inhibit GPS use
This method is not currently used by any of our vehicle types, but will be required to enable a user selectable 'indoor mode'.
2015-01-22 14:40:52 +09:00
priseborough 1033f5fc1e AP_NavEKF: Apply flow nav vehicle limits regardless of sensor health
It does not make sense to relax the limits on vehicle speed and nav gains just because we have received some invalid flow data. This could make the situation worse if the invalid data was being caused by too much speed.
If we are relying on flow data the vehicle limits should always be applied.
2015-01-22 14:40:50 +09:00
priseborough 14b51f6d74 AP_NavEKF: Unconditionally fuse velocity in constant velocity mode
The zero velocity measurements in this mode are by definition always correct and should never be rejected
2015-01-22 14:40:48 +09:00
priseborough 6663d80176 AP_NavEKF: Simplify nested logic - functionally equivalent
Additional if else statement was unnecessary
2015-01-22 14:40:45 +09:00
priseborough 12c3368c4d AP_NavEKF: Bypass GPS glitch logic when not aiding
When we are not using GPS measurements, we should not be allowing the GPS glitch logic to reset position states as this can interfere with operation of non GPS modes.
2015-01-22 14:40:43 +09:00
priseborough 5c8e71a8d1 AP_NavEKF: Don't reset the position measurement timeout if not aiding
When PV aiding is disabled, then the timeout time reference should not be reset becasue we want the position measurement timeout status to remain true the whole time the measurement is not being used.
2015-01-22 14:40:41 +09:00
priseborough c505a458de AP_NavEKF: Always declare a position measurement timeout if aiding not used
If position and velocity aiding is turned off, then the position measurement should always be reported as timed out.
2015-01-22 14:40:39 +09:00
priseborough 3b166372cc AP_NavEKF: Always declare a velocity measurement timeout if velocity not used
If position and velocity aiding is turned off, then the velocity measurement should always be reported as timed out.
2015-01-22 14:40:36 +09:00
priseborough 95c3197170 AP_NavEKF: Ensure velocity will not be reset unless needed for aiding 2015-01-22 14:40:34 +09:00
priseborough 8aeec82846 AP_NavEKF: Continually turn off aiding whilst the vehicle is disarmed
This prevents the possibility of any logic errors turning aiding back on.

AP_NavEKF: Fix bug in logic
2015-01-22 14:40:31 +09:00
priseborough 81ee339e25 AP_NavEKF: Synchronise non-aiding mode state corrections
Synchronise with covariance prediction to improve numerical stability and accuracy of angle corrections. The 'noise' this produces in the position and velocity estimate is irrelevantbecause these are not used by the control loops during this mode of operation (they are nominally zero anyway).
2015-01-22 14:40:29 +09:00
priseborough ae6b85e63d AP_NavEKF: Explicitly set aiding to off when disarmed
This fixes a bug that could cause the AHRS to drift whilst the vehicle was disarmed depending sensor combinations at startup.
2015-01-22 14:40:27 +09:00
priseborough fb1962b111 AP_NavEKF: Let reported position whilst disarmed show inertial errors
Showing the positon states (which are nominally zero) in addition to the last known offset can provide useful log information.
2015-01-22 14:40:25 +09:00
Andrew Tridgell e8017a5079 AP_NavEKF: cope with the changed semantics of airspeed.use() 2015-01-20 11:28:14 +11:00
priseborough c40c3632bb AP_NavEKF: Critical Bug Fix
Prevents possible loss of attitude reference for flights without optical flow and GPS.

The optical flow measurement timeout can reset the velocity states which decouples the position states from IMU errors and therefore significantly reduces the amount of attitude error correction.
2015-01-13 16:05:31 +13:00
Andrew Tridgell ef5cdb0d6c AP_NavEKF: use more array bounds checked variables 2015-01-09 11:05:07 +11:00
priseborough 3d46680348 AP_NavEKF: Make NED origin independent of home position
This enables the filter to report the last known position after disarm.
The LLH location of the filters NED origin is published and should be logged every time the vehicle is armed to assist with post-flight trajectory reconstruction.
The LLH location of the filters NED origin can be set externally whilst the vehicle is disarmed.
2015-01-09 10:51:24 +11:00
priseborough f0ea858e4c AP_NavEKF: Make LLH output report last known position in const pos mode 2015-01-09 10:51:24 +11:00
priseborough a0957a83f8 AP_NavEKF: Fix bug in reported position and velocity
The last known position was being output on the velocities when in constant position mode.
2015-01-09 10:51:24 +11:00
priseborough 7d1cd604a8 AP_NavEKF: Report last known position when GPS is lost 2015-01-09 10:51:24 +11:00
priseborough 1789dc08a3 AP_NavEKF: Correctly report position timeout when GPS is lost 2015-01-09 10:51:24 +11:00
Randy Mackay e6e6a781c1 AP_NavEKF: init filter status bits to zero 2015-01-09 10:51:23 +11:00
priseborough ffd9f7a4ed AP_NavEKF: Predict filter solution status 2015-01-09 10:51:23 +11:00
Randy Mackay 657afcfe7a AP_NavEKF: add pred_horiz_pos flags to filter status 2015-01-09 10:51:23 +11:00
Randy Mackay f4d8bc586c Nav_EKF: getFilterStatus returns nav_filter_status struct 2015-01-09 10:51:23 +11:00
Randy Mackay 8a914af4a8 AP_NavEKF: add nav_filter_status definition 2015-01-09 10:51:23 +11:00
priseborough d57e0b6bde AP_NavEKF: Remove compiler warning messages 2015-01-09 10:51:23 +11:00
priseborough a4ba4d1000 AP_NavEKF: Fix bug in optical flow innovation variances
Also improves protection against badly conditioned variances
2015-01-09 10:51:23 +11:00
priseborough 8bc8d1444a AP_NavEKF: Extend definition of GPS availability to include user inhibit 2015-01-09 10:51:22 +11:00
priseborough d0d49065e7 AP_NavEKF: Prevent potential repeated use of optical flow data 2015-01-09 10:51:22 +11:00
priseborough b0c703e4f7 AP_NavEKF: Fix bug in optical flow fusion control logic 2015-01-09 10:51:22 +11:00
priseborough d656c94bbc AP_NavEKF: Fix out of bounds index bug 2015-01-09 10:51:22 +11:00
priseborough 300ba65f64 AP_NavEKF: Remove duplicate flow measurement state correction 2015-01-09 10:51:22 +11:00
priseborough 92bb75a635 AP_NavEKF: Prevent load leveling from dropping flow measurements 2015-01-09 10:51:22 +11:00
priseborough 2f5aa210ce AP_NavEKF: Enable recovery from extended flow measurement rejection 2015-01-09 10:51:21 +11:00
priseborough 9f4baaa865 AP_NavEKF: Update flow debug logging 2015-01-09 10:51:21 +11:00
priseborough 8d1dae3ac1 AP_NavEKF: Improve optical flow terrain height estimation
The two state auxiliary EKF has been replaced with a single state filter that only estimates terrain offset. The new filter fuses a optical flow line of sight rate scalar (length of the optical flow LOS rate vector) which provides a terrain offset estimate that is less affected by yaw errors.
Estimation of focal length scale factor error in flight wasn't accurate enough and will be replaced with a pre-flight intrinsic sensor calibration procedure as the scale factor error does not change over time provided the lens assembly is not adjusted.

AP_NavEKF: Remove unwanted printf
2015-01-09 10:51:21 +11:00
priseborough d599fa588e AP_NavEKF: Don't allow EKF to initialise without GPS lock if we are a plane
This is needed because planes arm automatically.

AP_NavEKF: Fix bug in GPS patch
2015-01-09 10:51:21 +11:00
priseborough 2f0b1b3d9c AP_NavEKF: Fix bug preventing use of optical flow without GPS 2015-01-03 21:49:22 +11:00
Andrew Tridgell 16affe51be AP_NavEKF: avoid an extra quaternion copy 2015-01-03 15:44:07 +11:00
priseborough 69e86d3ea4 AP_NavEKF: Update EKF optical flow data logging 2015-01-03 14:09:12 +11:00
priseborough b651eac48d AP_NavEKF: Apply timeout to terrain offset validity reporting
The terrain offset solution status is usable for a short period of time without state updates so a timeout has been added which prevents the rapid changes in solution status due to short duration sensor read errors.
2015-01-03 14:09:09 +11:00
priseborough e6474d676e AP_NavEKF: Report correct horiz vel sol'n status during optical flow nav 2015-01-03 14:09:05 +11:00
priseborough 75201c8968 AP_NavEKF: Prevent divide by zero casued by Tnb_flow.c.z = 0 2015-01-03 14:07:13 +11:00
priseborough 8d3940ce1b AP_NavEKF: Improved use of enumerated type for aiding mode 2015-01-02 12:10:41 +09:00
priseborough 76d1378962 AP_NavEKF: Fix compiler warning messages 2015-01-01 23:39:48 +11:00
priseborough 3e3dd9d695 AP_NavEKF: Fix parenthesis error in EKF status reporting and clean up logic
This fixes a bug which could have caused the realative position status to be incorrectly reported under some conditions and also caused a compiler warning message. the logic used to report the filter solution status has been broken down into smaller, easier to understand statements.
2015-01-01 23:39:48 +11:00
priseborough c06f6e105e AP_NavEKF: Consistent initialisation of tuning parameters and variables
Non user adjustable parameters are now declared as 'const' in the header.
The _ prefix has been removed from non user adjustable tuning parameters.
We use a function call rather than a constructor to initialise variables because it enables the filter to be re-started in flight if necessary.
For consistency some signed integer type declarations have been changed to unsigned where appropriate.
2015-01-01 23:39:31 +11:00
priseborough f1dfa282dc AP_NavEKF: Consolidate constant velocity mode decision logic
The decision to switch to constant velocity mode during optical flow operation and te decision to switch back were previously being made in two different places in code. Both decisions are now made in the one place which makes the code easier to follow and maintain.
2015-01-01 19:53:21 +11:00
priseborough 9caf2ac895 AP_NavEKF: Make reversion to no GPS mode unambiguous 2015-01-01 19:53:21 +11:00
priseborough 58e9dd5dcd AP_NavEKF: Enumerate Position and Velocity aiding status 2015-01-01 19:53:21 +11:00
priseborough b016bae445 AP_NavEKF: Clean up reset of constant velocity mode
Move velocity store out of optical flow to velocity and position fusion control as it is a velocity fusion function.
Always clear the previous mode status
2014-12-31 13:16:16 +09:00
priseborough 3d207c316a AP_NavEKF: Change names for position and velocity hold modes
Name change done to avoid confusion with flight modes. modes are now referred to as constant position and constant velocity mode.
2014-12-31 13:16:15 +09:00
priseborough b650ee51a9 AP_NavEKF: Consolidate arming checks 2014-12-31 13:16:15 +09:00
priseborough 48cae0df15 AP_NavEKF: Fall back to attitude and hgt estimation for copter if GPS lost 2014-12-31 13:16:14 +09:00
priseborough b21f9daa90 AP_NavEKF: Update solution status reporting
This patch makes the reporting of an absolute position solution less abbiguaous and ensures that relative position is always true if absolute position is true
2014-12-31 13:16:13 +09:00
priseborough b6d300db19 AP_NavEKF: clean up determination of GPS availability 2014-12-31 13:14:22 +09:00
priseborough 40b02fc19a AP_NavEKF: Ensure filter doesn't try to use GPS after initialisation 2014-12-31 13:14:20 +09:00
priseborough bab1a69f1c AP_NavEKF: make position and velocity resets consistent with GPS usage 2014-12-31 13:14:18 +09:00
priseborough 0dc2356175 AP_NavEKF: Ensure initialisation methods read required sensor data 2014-12-31 13:14:16 +09:00
priseborough 5d1de79f08 AP_NavEKF: Modify initial values to make startup behaviour more consistent 2014-12-31 13:14:14 +09:00
priseborough a63af34d8f AP_NavEKF: Allow 10 seconds for the filter to settle after initialisation
Filter is declared unhealthy and will not arm for first 10 seconds after initialisation
2014-12-31 13:14:12 +09:00
priseborough 0a5de21dc7 AP_NavEKF: Fix bug in reporting of solution status
Because synthetic  position measurements at 0,0 are fused during position hold mode, a position timeout cannot be used as the only means of detecting position solution status.
2014-12-31 13:14:09 +09:00
priseborough 92c3026072 AP_NavEKF: Link process noise to arm status, not pos hold mode 2014-12-31 13:14:07 +09:00
priseborough a535b73a6d AP_NavEKF: Initialise timeout status to true
This status will be cleared when data arrives and is fused successfully
2014-12-31 13:14:04 +09:00
priseborough 363c1e393d AP_NavEKF: Latch use of position hold mode for duration of flight
Required to prevent acquisition of GPS mid flight causing unwanted change in position and velocity
A distinction has been mad between the arm and disarm transition and the decision to use position hold mode (formerly static mode)
2014-12-31 13:14:02 +09:00
priseborough a0a6c0362f AP_NavEKF: Relax timeout check applied to optical flow data
200 msec was too short and could lead to false positives. 5000 msec is the largest time we can go free inertial.
2014-12-31 13:14:00 +09:00
priseborough 5bd4ee9715 AP_NavEKF: Use compensation for baro delay in position hold mode 2014-12-31 13:13:58 +09:00
priseborough 4dc1ee2d66 AP_NavEKF: Rename static mode to avoid confusion with other non-GPS modes
This renames static mode as posHoldMode to make it clearer what this and the other non-GPS modes do
2014-12-31 13:13:54 +09:00
priseborough b160f4c03b AP_NavEKF: Compensate optical flow fusion for GPS glitch recovery offset 2014-12-31 13:13:52 +09:00
priseborough e4c969084d AP_NavEKF: Improve behaviour recovering from a GPS timeout
When regaining GPS after a timeout, an offset is applied when fusing  GPS velocity so that GPS velocity and position data as fused by the EKF is kinematically consistent.
This velocity offset is also accounted for when fusing air data so that wind estimates are not corrupted when the GPS position offset is being pulle back to zero.
The intended behaviour is that the EKF position will be pulled back to the GPS position at a rate of 5m/s for planes and 1 m/s for copters. This avoids large deviations in trajectory when GPS is regained.
2014-12-31 13:13:50 +09:00
priseborough 6eb533121c AP_NavEKF: Add static mode to solution status message 2014-12-31 13:13:48 +09:00
priseborough 5c3a56a087 AP_NavEKF: Fix error in comments 2014-12-31 13:13:46 +09:00
priseborough 3891dada78 AP_NavEKF: remove unnecessary function 2014-12-31 13:13:44 +09:00
priseborough a16253796f AP_NavEKF: Fix bug preventing the non-GPS mode being selected externally
When on the ground it is likely the flow sensor will be returning  data that does not meet the minimum quality requirements selected.
The previous check was for the presence of valid data. This has been loosened to look for the presence of data.
When the vehicle becomes airborne, the quality of flow data normally improves as the image comes into focus.
2014-12-31 13:13:42 +09:00
priseborough a42100e4c5 AP_NavEKF: Improved handling of no GPS
This patch enables indoor operation of the EKF by putting it into static mode if optical flow operation is not enabled and no GPS is available
2014-12-31 13:13:40 +09:00
priseborough 73a06cd0c1 AP_NavEKF: Fix bug causing magnetic field state learning to be forgotten 2014-12-31 13:13:37 +09:00
priseborough bf89c56e54 AP_NavEKF: Fix comments error in description of flow sensor sign conventions 2014-12-31 13:13:35 +09:00
priseborough 4eb19c2324 AP_NavEKF: Rationalise health status reporting
1) Un-used public methods to report height and position drifting have been removed
2) A time-out has been added to the airspeed innovation consistency check so that if we are relying on airspeed to constrain velocity drift, a filter divergence or other fault that causes the airspeed to be continually rejected will trigger a change in health status.
3) A timeout of velocity, position or height measurements does not cause a filter fault to be reported. Timeouts can be due to sensor errors and do not necessarily indicate that the filter has failed.
4) Time-outs of various measurements are used to present a consolidated bitmask which inidicates which parts of the solution can be used, eg attitude, height, velocity, relative position, absolute position, etc.
2014-12-31 13:13:31 +09:00
priseborough 78b30e4ce5 AP_NavEKF: Increase rate at which GPS glitch offsets are reduced for planes 2014-12-31 13:13:29 +09:00
priseborough f2c506339a AP_NavEKF: Reduce time required to recover from GPS timeouts
The time required for GPS to be lost or rejected before vehicles with airspeed sensors either reset to GPS or invoke the zero side-slip assumption to constrain drift has been reduced from 15 to 10 seconds
A duplicate zeroing of the GPS position offset has been removed
If the vehicle is a non hovering vehicle (eg a plane) then the speed at which the GPS offset is pulled back to zero after a reset is increased from 1 to 3  m/s

This also improves recovery from bad inertial data for planes
2014-12-18 21:50:40 +11:00
priseborough f73816dbb5 AP_NavEKF: Improve robustness to long periods without GPS 2014-12-18 21:07:45 +11:00
priseborough 3afde0061f AP_NavEKF: Use named states for velocity reset
Readibility improvement
2014-12-18 17:29:50 +11:00
priseborough f6ce25df2a AP_NavEKF: Do not reset vertical velocity state from GPS
Doing this can cause large height and height rate errors if large GPS velocity errors cause the GPS tn be rejected for long enough to cause a timeout and reset of states.
2014-12-18 17:29:47 +11:00
Randy Mackay e581e81da5 AP_NavEKF: reorder declation to fix compiler warning
No functional change
2014-12-11 15:37:56 +09:00
Andrew Tridgell cb9c518ab8 Revert "AP_NavEKF : Reduce ripple in estimates that can cause copter motor 'pulsing'"
This reverts commit 13df6fb1c9.

This patch was a result of an incorrect merge of the optflow branch
into master. It reintroduced the bug fixed by this commit:

  AP_NavEKF : Fix bug in reset of GPS glitch offset
  8aa267f75f
2014-12-08 07:53:47 +11:00
priseborough a2bd3b4a42 AP_NavEKF: Add public method returning height above ground level 2014-12-06 18:16:51 +11:00
priseborough d701cfcb75 AP_NavEKF: Output terrain relative PosD when relying on Optical Flow 2014-12-06 18:16:51 +11:00
priseborough 0156d846f1 AP_NavEKF: Increase height at which nav gain reduction starts
Compensates for optical flow induced noise increase with height.
2014-12-06 18:16:51 +11:00
priseborough a905432ffe AP_NavEKF: reduce height at which nav gain reduction starts 2014-12-06 18:16:51 +11:00
priseborough 5785272933 AP_NavEKF: Improve robustness to corrupted flow sensor data 2014-12-06 18:16:51 +11:00
priseborough b1d44d4dde AP_NavEKF: Add protection for negative height above ground 2014-12-06 18:16:50 +11:00
priseborough d994da0886 AP_NavEKF: Expand EKF speed limit public method to handle control limits 2014-12-06 18:16:50 +11:00
priseborough bc2255d6b1 AP_NavEKF: Improve comments in setInhibitGPS public method 2014-12-06 18:16:50 +11:00
priseborough 416eaf4633 AP_NavEKF: Apply single definition of using optical flow 2014-12-06 18:16:50 +11:00
priseborough b56b68ce10 AP_NavEKF: Add public method reporting horizontal speed limit
This is required if using optical flow, as depending on height, the speed must be limited to prevent the sensor saturating
2014-12-06 18:16:50 +11:00
priseborough c8fb376cc4 AP_NavEKF: Fix bug in bias rate of change limiting
This doesn't change the behaviour, but means the result is achieved using the correct parameters, and comments are consistent
2014-12-06 18:16:50 +11:00
priseborough 599e53f3f2 AP_NavEKF: Prevent flow scale factor updating on ground 2014-12-06 18:16:49 +11:00
priseborough 083e22966c AP_NavEKF: Add public method to report available output data 2014-12-06 18:16:49 +11:00
priseborough e53d28854e AP_NavEKF: Add public method to inhibit GPS use and clean-up GPS use logic
This provides the calling vehicle software the abiity to request the EKF to not use GPS.
An integer is returned that indicates the type of operation available:
0 = request rejected (request will only be accepted if the EKF is in static mode, eg pre-armed)
1 = request accepted, attitude, vertical velocity and position estimates available
2 = request accepted, attitude, height rate, height, horizontal velocity and relative position estimates available
2014-12-06 18:16:49 +11:00
priseborough 8fb1d9cf8d AP_NavEKF: Fix bug preventing opt flow scale factor estimation
Also removes un-used variable declarations
2014-12-06 18:16:49 +11:00
priseborough a78920761c AP_NavEKF: Update comments in flow data interface 2014-12-06 18:16:49 +11:00
priseborough 52c7e56a4a AP_NavEKF: Add parameter for max valid optical flow rate magnitude 2014-12-06 18:16:49 +11:00
priseborough 6f8971d80a AP_NavEKF: Speed up flow sensor gyro bias correction 2014-12-06 18:16:49 +11:00
priseborough d7ad45ebda AP_NavEKF: Don't fuse flow measurements if too big 2014-12-06 18:16:49 +11:00
priseborough 84944fdd4e AP_NAvEKF: Revert back to 10Hz fusion 2014-12-06 18:16:49 +11:00
priseborough 1f78a73cdb AP_NavEKF: Make flow measurement delay vehicle specific
This takes into account the inter-sampling delay between the flow driver and the APM software which depends on the rate at which the dirver is being checked. This is 50Hz for plane and rover, and 200Hz for Copter.
2014-12-06 18:16:49 +11:00
priseborough 5f941655a8 AP_NavEKF: changes to support to 20Hz flow fusion rate 2014-12-06 18:16:48 +11:00
priseborough 0bf991eef9 AP_NavEKF: Fix bug in optical flow fusion smoothing 2014-12-06 18:16:48 +11:00
priseborough 839b814d12 AP_NavEKF : Inhibit flow and range fusion in static mode 2014-12-06 18:16:47 +11:00
priseborough 9b9934ac06 AP_NavEKF : fix velocity timeout bug during optical flow operation 2014-12-06 18:16:47 +11:00
priseborough 517026980b AP_NavEKF : Add fault and timeout logging 2014-12-06 18:16:47 +11:00
priseborough f640ec30ff AP_NavEKF : Reset held velocity on arming
This held velocity is used to constrain the drift in the optical flow solution before the vehicle is high enough for the optical flow sensor to work.
2014-12-06 18:16:47 +11:00
priseborough 06c19a3a4d AP_NavEKF : Update optical flow debug logging 2014-12-06 18:16:47 +11:00
priseborough 1791dec622 AP_NavEKF : Fix velocity hold mode 2014-12-06 18:16:47 +11:00
priseborough 84421e0a35 AP_NavEKF : Adjust initial flow scale factor and limits 2014-12-06 18:16:47 +11:00
priseborough 573633daf7 AP_NavEKF : Fix incorrect use of flow sensor time-stamp
flow sensor time stamp is now issued by the flow sensor and is on a different time-base
2014-12-06 18:16:47 +11:00
priseborough 9ea97c1a38 AP_NavEKF : Modify optical flow data interface
Sign conventions have changed
2014-12-06 18:16:46 +11:00