Commit Graph

191 Commits

Author SHA1 Message Date
priseborough edc79ca2a4 AP_NavEKF: Increase divergence test margin based on analysis of more user flight logs
Analysis of copter logs has shown cases with a healthy EKF where spikes in EKF4.DS of up to 25% of the threshold have occurred.
A value of closer to 10% for normal operation is preferred.
2014-05-24 22:20:24 +10:00
priseborough 5fe0d2c1b2 AP_NavEKF: Add protection for accel bias estimation errors
Don't do bias estimation if tilted by more than 60 degrees to prevent scale
factor errors affecting result unnecessarily.
Prevent Kalman gain from having the wrong sign due to numerical errors
associated with small process noise values.
Allow smaller Z accel bias process noise values to be set
2014-05-18 08:09:00 +10:00
priseborough 3222e8f7cb AP_NavEKF: Default parameter adjustments
Bring Plane glitch protection thresholds into alignment with copter and
rover
Slight increase in accelerometer bias process noise to prevent bias
estimate divergence into limits (Rover and Plane only as Copter does not
seem respond as well to this change)
effective increase in threshold on divergence test to allow increased
margin for bad GPS velocities
2014-05-18 08:08:49 +10:00
priseborough e40e50e2e1 AP_NavEKF: Prevent start-up transients re-tripping divergence test 2014-05-16 22:05:22 +10:00
priseborough a19015ed61 AP_NavEKF: Scale divergence check with covariance
This provides consistent behaviour for a range of gyro bias process
noise settings and automatically adjusts sensitivity as filter learns bias
2014-05-16 21:24:25 +10:00
priseborough 0337d44b2e AP_NavEKF: Fix bug causing immediate clearing of diverged status on reset 2014-05-16 21:24:04 +10:00
priseborough d150904dc6 AP_NavEKF: Increase gyro bias process noise
This is required to stop the bias estimate from becoming too static
towards the end of longer flights.
2014-05-16 21:24:04 +10:00
Andrew Tridgell 5edf4ba596 AP_NavEKF: fixed up handling of bitfields in faultStatus
Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2014-05-15 21:42:39 +10:00
priseborough ce8e1daa16 AP_NavEKF: Improved divergence detection and reset
Divergence is now detected by looking for very large changes in the gyro
bias. This will cause the filter to be reset and declared unhealthy for
10 seconds.

Don't reset filterDiverged status immediately during reset

Set filterDiverged true if covariance blows up

Add fault status reporting
2014-05-15 21:14:21 +10:00
Andrew Tridgell 85ebe81ed3 AP_NavEKF: fixed logic for divergence test
Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2014-05-11 18:00:38 +10:00
priseborough 40dc0e56fe AP_NavEKF: Add protection for badly conditioned innovation variances 2014-05-11 18:00:38 +10:00
priseborough 925c5751bd AP_NavEKF: Add ability to inhibit in-flight mag cal and clean up moding
This will enable in-flight magnetometer calibration to be inhibited unconditionally,
This is required for long balloon carriage flights where ground speed can be high
enough to put it into in-air state, but with very poor observability of magnetic field
states causing bad state estimates and heading offsets to develop over time.

The covariance matrix no longer has rows and columns artificially zeroed when in static
mode. Instead booleans indicating whether wind or magentic field state estimation is
active are used to:

a) Set the process noise on these states to zero to stop their variances from increasing
unchecked when not being updated, and
b) Turn off updates for these states when measurement fusion is being performed.

This reduces the likelihood of a badly conditioned covariance matrix forming
during static mode operation.

A filter divergence check has also been added that will declare the filter unhealthy if
position, velocity and magnetic field observations are all failing their innovation
consistency checks. This unhealthy status will persist for 10 seconds after the
condition clears.

AP_NavEKF: Remove unnecessary zeroing of wind covariances
2014-05-11 18:00:38 +10:00
priseborough 3026ccee13 AP_NavEKF: Use baro data during launch transients whilst in static mode
Baro data can be used as it will still be valid during the launch and
is not a synthesised measurement.
2014-05-11 18:00:38 +10:00
priseborough 114bd56e2a AP_NavEKF: Fix display names in parameter list 2014-04-30 06:35:41 +10:00
priseborough 5fefce5899 AP_NavEKF: Synthetic sideslip fusion numerical error protections 2014-04-29 17:26:45 +10:00
priseborough ecc8e45eda AP_NavEKF: Fix bug in position reset logic 2014-04-23 18:16:02 +10:00
Andrew Tridgell 25667a11a0 AP_NavEKF: use AHRS vehicle class for sideslip calculation
Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2014-04-21 18:13:12 +10:00
Andrew Tridgell 5acd17b843 AP_NavEKF: cleanup some build warnings
Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2014-04-21 18:13:12 +10:00
priseborough bd28cdbdcf AP_NavEKF: Improved magnetometer consistency checks
A magnetometer axis that fails the innovation consistency check will cause
all axes not to be used. If this condition continues for 10 seconds, a
magnetometer timeout condition will be declared. When the timeout has
occurred, if it is not a fly forward vehicle, then individual channels
will be used again, but with a reduced weighting.
2014-04-21 16:31:31 +10:00
Andrew Tridgell 610a930612 AP_NavEKF: catch covarience errors and reset filter
this catches covariance values beyond a reasonable limit and resets
the filter is they happen
2014-04-21 15:37:08 +10:00
Andrew Tridgell 4756dbee84 AP_NavEKF: fixed millisecond subtraction for rollover
Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2014-04-21 13:16:20 +10:00
Andrew Tridgell 68f1ae3036 AP_NavEKF: fixed some matlab ! -> ~ typos
Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2014-04-20 21:44:37 +10:00
Andrew Tridgell 4abc2999a6 AP_NavEKF: start with a wind estimate of 3m/s, when no direct measurement
this will cope better with users with low roll/pitch gains, to ensure
they get enough control on takeoff

Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2014-04-13 19:42:23 +10:00
priseborough d745dc2b6f AP_NavEKF : Increased position gate default to reduce impact of accel errors
Flight testing with windup turns has shown that the position gate threshold
can be tripped with good GPS data causing position jerks. This increases the
initial GPS glitch rejection threshold to effectively 5m when using the
default POSNE_NOISE value of 0.5m.
2014-04-13 19:37:22 +10:00
priseborough 188bea6bab AP_NavEKF : Enable calc of wind velocity when not using airspeed sensing
This patch also cleans up the logic associated with use of the synthetic
sideslip measurement so that it can never be used for a non fly-forward
vehicle type

This patch adds functionality that initialises the wind-speed vector to the
reciprocal of the ground speed vector, and scaled to 6 m/s. On average this gives
a better initial wind velocity estimate on launch by assuming:

a) launch will be into wind
b) wind speed is equal to global average

It also helps prevent a headwind causing initial underestimation of airspeed
causing high autopilot gains and limit cycles on climb-out, until first
turn when the EKF is able to estimate the wind.
2014-04-13 19:37:19 +10:00
Emile Castelnuovo 25f1c5774f AP_NavEKF: added #defines for VRBRAIN board 2014-04-08 16:19:19 +10:00
priseborough db043744a4 AP_NavEKF : Reduce Z accel bias process noise to provide a more stable estimate 2014-04-07 21:08:25 +10:00
priseborough 1f8b5a6d23 AP_NavEKF : Tighten GPS velocity glitch gate default setting for plane 2014-04-07 21:08:15 +10:00
priseborough 0c2489b07b AP_NavEKF : Fix bug in logging of airspeed innovation consistency ratio 2014-04-07 21:01:00 +10:00
priseborough 95c83255d7 AP_NavEKF : adjust default values for accelerometer process noise
Slows down estimate and allows for smaller values to be set
2014-04-07 21:00:43 +10:00
Andrew Tridgell 07d621c4be AP_NavEKF: used state structure in more places
makes the code a bit easier to read

Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2014-04-04 21:30:16 +11:00
priseborough aa5335b16e AP_NavEKF : Improved GPS position glitch handling
When using GPS after previously rejecting it, the GPS position will
always be offset if outside the specified glitch radius. This was the
original intent of the design and makes handling of glitches smoother.

It has been tested on replay using glitchy flight data
2014-04-04 21:01:22 +11:00
priseborough b1786cf1e5 AP_NavEKF : Do not reset on GPS velocity timeout if good position data 2014-04-04 21:01:20 +11:00
priseborough d25883f712 AP_NavEKF : Limit rate of Z accel bias adaptation
Aliasing can causes the bias estimate to fluctuate very rapidly as it tries
to keep up, which degrades the benefit of switching between
accelerometers to avoid aliasing.

This patch give a much more stable bias estimate during aliasing, and
allows the bias to adapt at a maximum rate of 1.0 m/s2 in 50 seconds
2014-04-04 21:01:18 +11:00
priseborough 36b3cbc365 AP_NavEKF : Relax aliasing check limits
This reduces the chance of noisy data inhibiting GPS glitch protection
2014-04-04 21:01:15 +11:00
priseborough 0ae736c3a0 AP_NavEKF : clean up convoluted logic used in sensor health checks
This doesn't change the behavior, but does make the code easier to
understand
2014-04-04 21:01:13 +11:00
Andrew Tridgell cd3038fabd AP_NavEKF: fixed return of offset in getVariances() 2014-04-03 07:49:06 +11:00
Andrew Tridgell a7f213a5c5 AP_NavEKF: use pythagorous2() 2014-04-01 22:13:03 +11:00
priseborough 04036d7777 AP_NavEKF : Updated GPS glitch protection logic
This adds new functionality to the detection and compensation of GPS
glitches:

1) A maximum allowable innovation is calculated using the GPS noise
parameter multiplied by the gate, with an additional component allowing
for growth in position uncertainty due to acceleration error since
the last valid measurement
2) Includes per vehicle type values for the acceleration error limit
3) If the innovation length exceeds the maximum allowable, no fusion occurs
4) If no fusion has occurred for long enough such that the position uncertainty
exceeds the maximum set by a per vehicle parameter or a maximum time, an offset
is applied to the GPS data to so that it matches the value predicted by the filter
5) The offset is never allowed to be bigger than 100m
6) The offset is decayed to zero at a rate of 1.0 m/s to allow GPS jumps to
be accommodated gradually
7) The default velocity innovation gate has been tightened up for copter and rover
8) The variance data logging output has been updated to make it more useful
2014-04-01 21:22:14 +11:00
Andrew Tridgell 5a2e84e792 AP_NavEKF: changes for new GPS API 2014-04-01 06:38:24 +11:00
priseborough 9c5f564dc5 AP_NavEKF : Fixes bug in initial earth magnetic field states
The calculation for these states was not being bias corrected
2014-03-30 07:43:52 +11:00
priseborough e1819bb53a AP_NavEKF : Add initial parameter defaults for Copter, Rover and Plane 2014-03-29 14:06:43 +11:00
priseborough 55c60b8f07 AP_NavEKF : Reduce Magnetometer innovation consistency check threshold 2014-03-26 21:29:47 +11:00
priseborough 45b1a2fa46 AP_NavEKF : Reduce GPS position innovation consistency fail threshold
This patch reduces the maximum acceptable GPS jump from approximately 16 to 8 metres
This will provide copters with more protection for close in loiter situations
2014-03-26 21:29:45 +11:00
Andrew Tridgell bafc664750 AP_NavEKF: use APM_BUILD_TYPE() macro 2014-03-26 12:42:11 +11:00
Andrew Tridgell e3792f9b26 AP_NavEKF: added a mechanism for per-vehicle-type defaults in EKF 2014-03-26 12:30:17 +11:00
priseborough 17cdac7bc8 AP_NavEKF : Clean up angle and mag field initialisation
This path reduces duplicated code, eliminates unused variables and
causes the earth magnetic field states to be reset when exiting static mode
which will occur every time copter is armed. This enables copters to be
powered on and initialised inside vehicles or houses, without bad earth
field values affecting flight.
2014-03-24 19:54:48 +11:00
priseborough 7ae86b3979 AP_NavEKF : Track baro height observations pre-arm
This prevents copter from failing the pre-arm height discrepancy test
2014-03-23 18:25:50 +11:00
priseborough 7780d55788 AP_NavEKF : Prevent large magnetic field adaptations early in flight 2014-03-22 19:55:26 +11:00
Paul Riseborough f7007569d1 AP_NavEKF : Fix bug that limits copter sensor delay compensation to 125
msec
2014-03-21 21:52:20 +11:00