Commit Graph

432 Commits

Author SHA1 Message Date
Andrew Tridgell 7a76f72bf5 AP_AHRS: added uptime_ms() interface 2015-05-20 15:22:14 +10:00
Andrew Tridgell 5514a9f690 AP_NavEKF: base EKF decisions on vehicle class
using the vehicle class rather than the build macros allows this to
work correctly in replay
2015-05-19 15:21:22 +10:00
Andrew Tridgell 92daa15ccc AP_AHRS: on plane and rover make AHRS unhealthy when EKF not initialised
planes and rovers need full absolute position from the EKF if the EKF
is going to be used. We don't want users to arm without full
capabilities
2015-05-19 15:21:21 +10:00
Andrew Tridgell 29f0561ce4 AP_AHRS: reject EKF for plane when we have GPS and aren't fusing
plane users would prefer to use GPS in this case
2015-05-17 21:24:57 +10:00
Paul Riseborough c2ac80cc63 AP_AHRS: Prevent copter from switching to DCM unless EKF has severe errors 2015-05-13 16:11:13 +09:00
Andrew Tridgell 3529e02675 AP_AHRS: if we have 3 gyros then only use first two
the 3rd gyro on a PH2 has a lot more noise as it is not vibration
isolated
2015-05-09 21:00:49 +10:00
Randy Mackay 3390d9932e AP_AHRS: fix example sketch 2015-05-09 12:23:05 +09:00
Peter Barker 463270e0ee AP_AHRS: avoid FPE when we don't have a compass reading 2015-05-05 15:02:35 +10:00
Andrew Tridgell 4d4a607b80 AP_AHRS: revert AP_Math class change 2015-05-05 13:27:05 +10:00
Tom Pittenger 20f47417d5 AP_AHRS: compiler warnings: apply is_zero(float) or is_equal(float) and float to doubles 2015-05-05 13:26:55 +10:00
Andrew Tridgell e597575747 AP_AHRS: fix for HAL_SITL rename 2015-05-05 09:45:54 +10:00
Andrew Tridgell 6bfca648b9 AP_AHRS: raise DCM P gains when disarmed for first 20 seconds 2015-04-28 14:07:39 +10:00
Tom Pittenger e28c555889 AHRS_DCM: fix compile warnings re float constants
Also fix example sketch
2015-04-24 12:26:08 +09:00
Paul Riseborough 7f1749dc1c AP_AHRS: Allow EKF to pull data from range finder object 2015-04-24 10:56:58 +09:00
Paul Riseborough 405862bd8f AP_AHRS: Reduce time delay for EKF initialisation 2015-04-23 20:35:52 +09:00
Paul Riseborough 5184bca87f AP_AHRS: Prevent DCM reporting good tilt error when inverted 2015-04-23 20:35:39 +09:00
Paul Riseborough ea8217bd3a AP_AHRS: Reduce time constant on filtering of DCM error reporting
Reduces time constant from 2 to 1 second to make data more useful for pre-flight alignment checks by the EKF
2015-04-23 20:35:35 +09:00
Randy Mackay 6e30093924 AP_AHRS: correct sanity checks on update_trig 2015-04-23 09:45:43 +09:00
Jonathan Challinger 6a6ccb4f32 AP_AHRS: add sanity checks 2015-04-22 21:50:51 +09:00
Randy Mackay c6f71ea2e0 AHRS: make get_error_rp and get_error_yaw const 2015-04-21 22:42:17 +09:00
Andrew Tridgell a0969905ce AP_AHRS: make get_error_rp() and get_error_yaw() const
this makes them usable by multiple consumers, and allows use by EKF
2015-04-21 21:42:17 +10:00
Andrew Tridgell d7249cc1e6 AP_AHRS: only use EKF for plane and rover if all data available
we need position and velocity to be working for plane and rover
2015-04-14 09:57:45 +10:00
Paul Riseborough ff9917d338 AP_AHRS: Fix bug preventing EKF from initialising 2015-04-10 11:07:42 +09:00
Jonathan Challinger dc5bdd5ad8 AP_AHRS: use filtered INS output to compute _accel_ef_blended 2015-04-09 20:19:56 +09:00
Paul Riseborough d44cf14178 AP_AHRS : Publish EKF learned compass offsets 2015-04-03 15:24:47 -07:00
Andrew Tridgell 8ba043e593 AP_AHRS: fixed EKF startup bug
This fixes the EKF for when GPS lock takes more than 10 seconds

fixes issue #2010
2015-03-28 10:52:22 -07:00
Randy Mackay 98efcd5f03 AHRS: always use EKF for copter 2015-03-19 15:15:51 +09:00
Randy Mackay 7f25938834 AHRS: fix example sketch 2015-03-16 20:29:19 +09:00
Jonathan Challinger f92c711d14 AP_AHRS: define AP_AHRS_TYPE to be the type of AHRS in use 2015-03-16 09:14:03 +11:00
Andrew Tridgell 585a105128 AP_AHRS: use compass->last_update_usec() 2015-03-14 12:31:50 +11:00
Andrew Tridgell b488d6de00 AP_AHRS: fix for new compass API 2015-03-13 18:46:17 +11:00
Andrew Tridgell 031c81beee AP_AHRS: removed call to 1D accel cal 2015-03-12 12:50:29 +11:00
Andrew Tridgell 6781a8d329 AP_AHRS: fixed get_position for EKF to use correct relative altitude
we need to use the EKF relative height plus the current AHRS home
2015-02-21 10:12:53 +11:00
Jonathan Challinger 180c85817d AP_AHRS: remove armed state, use hal.util soft_armed state 2015-02-11 20:25:11 +11:00
mirkix 49d81a9c99 AP_AHRS: fix apm1 oilpan support 2015-02-11 18:22:39 +11:00
Randy Mackay b66a1135d9 AHRS: fix example sketch compile error 2015-02-03 15:57:11 +09:00
Andrew Tridgell ee9c778834 AP_AHRS: added a get_NavEKF_const() function
needed for AP_Mount_MAVLink

Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2015-02-03 09:49:16 +11:00
Andrew Tridgell 68f64fa11c AP_AHRS: make the healthy() method const 2015-02-01 14:13:52 +11:00
Randy Mackay d8664d15d6 AHRS: fix example sketch 2015-01-28 17:15:35 +09:00
Andrew Tridgell ed0a56cc3c AP_AHRS: cope with the changed semantics of airspeed.use() 2015-01-20 11:27:58 +11:00
Andrew Tridgell d2c827aa4b AP_AHRS: updates for new AP_Baro API 2015-01-09 11:50:56 +11:00
Andrew Tridgell b499cd1b59 AP_AHRS: fixed examples build
using a relative include works as the object is just passed through,
not used, in this header
2015-01-05 07:04:27 +11:00
Andrew Tridgell 70c2aeca42 AP_AHRS: make optflow available via AHRS
same pattern as compass and airspeed sensor
2015-01-03 14:16:34 +11:00
priseborough 5b8265ad6f AP_AHRS: Expand EKF speed limit public method to handle control limits 2014-12-06 18:16:50 +11:00
priseborough 83775554ea AP_AHRS: Publish EKF ground speed limit 2014-12-06 18:16:50 +11:00
priseborough 5532750a99 AP_AHRS: Add public method to inhibit GPS useage when using EKF
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 44e1695d5a AP_AHRS : Enable EKF start without GPS 2014-12-06 18:16:46 +11:00
priseborough a4984a1e76 AP_AHRS : Add range finder health status to EKF optical flow data 2014-12-06 18:16:44 +11:00
priseborough 12b012a00e AP_AHRS : temporary mods to test use of flow sensor internal gyro data 2014-12-06 18:16:44 +11:00
priseborough 7b76fc29fb AP_AHRS : EKF optical flow fusion support preliminary changes 2014-12-06 18:16:44 +11:00
Randy Mackay 4452aa8448 AP_AHRS_DCM: compile error fix for low speed CPUs
Also correct initialisatoin order to remove compiler warning
2014-12-05 19:43:05 +09:00
Jonathan Challinger 9261dfdefb AP_AHRS_NavEKF: overload get_accel_ef and get_accel_ef_blended functions 2014-12-05 19:40:08 +09:00
Jonathan Challinger 4975cefd84 AP_AHRS_DCM: update _accel_ef_blended 2014-12-05 19:40:06 +09:00
Jonathan Challinger 033ee3c900 AP_AHRS: Add get_accel_ef_blended function 2014-12-05 19:40:04 +09:00
Randy Mackay 9e731550fd AHRS: default EKF on for copter 2014-12-01 17:29:39 +09:00
Andrew Tridgell 38c1b622f3 AP_AHRS: fixed example build on APM2 2014-11-28 17:59:18 +11:00
Andrew Tridgell 89cdae62b4 AP_AHRS: fixed example build 2014-11-28 10:40:52 +11:00
priseborough 2c07299c04 AP_AHRS : Add reset of EKF gyro bias states 2014-10-29 15:32:18 +09:00
Randy Mackay dffcfb42bc AHRS: add reset_gyro_drift method 2014-10-28 20:25:33 +09:00
Andrew Tridgell 26de54c29a AP_AHRS: cope with 90 degree pitch in update_trig()
this prevents a numerical error in Replay
2014-10-25 11:21:04 +11:00
Andrew Tridgell f79ce92673 AP_AHRS: fixed example build 2014-10-24 12:10:40 +11:00
Randy Mackay 39c8535223 AHRS_DCM: sanity check AHRS_RP_P and AHRS_YAW_P 2014-10-21 21:41:41 +09:00
Andrew Tridgell 270bac4472 AP_AHRS: make get_position() const
This allows use from within AP_Mission
2014-10-20 08:36:20 +11:00
Andrew Tridgell 4ad643b233 AP_AHRS: use a common function for updating the CD values
this ensures the wrapping of yaw is consistent between the 3 use cases
2014-10-15 13:18:08 +11:00
Andrew Tridgell eec5cd5add AP_AHRS: restore DCM attitude before update()
The DCM drift correction code uses the current attitude to calculate
error values to update its gyro drift correction. If we were using EKF
then without this patch the DCM code running as an alternative AHRS
source would be using the EKF attitude for calculating the error
value, leading to very bad gyro drift estimation
2014-10-15 11:15:33 +11:00
Andrew Tridgell 63c06ea2af AP_AHRS: fixed calls to DCM in parent class
use_compass() and reset() are common to AP_AHRS_DCM and
AP_AHRS_NavEKF. As AP_AHRS_NavEKF is a child of AP_AHRS_DCM, when we
call use_compass() from within AP_AHRS_DCM we actually end up calling
AP_AHRS_NavEKF::use_compass().

This has the effect of disabling the compass in DCM when EKF is active
and EKF has decided not to use the compass. That means that the DCM
yaw (and in fact the whole attitude) can get badly off while EKF is
enabled, making DCM an ineffective fallback if EKF fails.

The fix is to call the specific class versions of use_compass() and
reset()
2014-10-15 10:12:50 +11:00
Andrew Tridgell 809b6cc855 AP_AHRS: added get_yaw_rate_earth()
used to estimate course correction on takeoff
2014-10-07 07:17:46 +11:00
Randy Mackay 85eee31510 AHRS: rename ekfNotStarted method to initialised
Also created default implementation in AP_AHRS class so AP_AHRS_DCM does
not need to implement it.
2014-10-02 14:40:54 +09:00
priseborough 7cea7c6a18 AP_AHRS : add method to report if EKF is waiting to start 2014-10-02 14:38:29 +09:00
priseborough 7370e07c8d AP_AHRS : Prevent EKF starting if GPS sats less than AHRS_GPS_MINSATS 2014-10-01 12:55:29 +10:00
Andrew Tridgell e9a9e33280 AP_AHRS: use EKF use_compass() if EKF enabled
this allows magfailed status to show on console via SYS_STATUS health
bits
2014-08-24 21:00:56 +10:00
Randy Mackay a6de3283b6 AHRS_DCM: init members to resolve compiler warnings 2014-08-14 11:27:31 +09:00
Andrew Tridgell 0f5b65e40e AP_AHRS: fixed example build 2014-08-13 21:46:04 +10:00
Przemek Lekston ae4814a773 AP_AHRS_DCM.cpp: changed the direction of position projection to ensure correct behavious in crosswind 2014-08-07 12:34:30 +10:00
Andrew Tridgell 82d0666501 AP_AHRS: fixed example build 2014-07-25 17:54:04 +10:00
Andrew Tridgell 6a275372dd AP_AHRS: ensure get_position() fills in flags 2014-07-25 11:40:16 +10:00
Randy Mackay d23b685023 AP_AHRS: add empty virtual destructor 2014-07-16 14:56:54 +09:00
Randy Mackay 1f2e38ed28 AHRS: initalise members to reduce compiler warnings 2014-07-16 14:38:26 +09:00
Andrew Tridgell 28fedba4d8 AP_AHRS: fixed gyro_bias sign, and pre-calculate gyro_estimate for EKF
this allows us to return a constant vector for the corrected gyro
estimate. Based on discussions with Jon Challinger
2014-07-13 21:56:39 +10:00
Jonathan Challinger 966d66ef40 AP_AHRS_NavEKF: use gyro drift states from EKF in get_gyro 2014-07-13 21:34:44 +10:00
Jonathan Challinger 61987f6655 AP_AHRS: Fixed DCM get_gyro function
Previously incorporated the attitude correction terms into the return. Now only returns the drift-corrected gyro.
2014-07-13 21:19:29 +10:00
Andrew Tridgell d70bee9249 AP_AHRS: fix for HAL_GPIO_* 2014-06-02 10:42:36 +10:00
Andrew Tridgell b3c1e515dc AP_AHRS: when no accel info available in buffer use current value
this prevents an initialisation error, and is reasonable in flight too

Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2014-05-15 22:19:54 +10:00
Andrew Tridgell 315290029a AP_AHRS: fixed check of accel sensor health
we need to check health of each accelerometer separately
2014-05-15 22:18:56 +10:00
Andrew Tridgell 1a05c27bbb AP_AHRS: added healthy() function
this will be used to report when the AHRS subsystem becomes unhealthy
2014-05-15 21:14:21 +10:00
Andrew Tridgell c8c6e05a4a AP_AHRS: added vehicle class to AHRS
used by EKF to control use of get_fly_forward()
2014-04-21 18:13:12 +10:00
Andrew Tridgell 4d24a86088 AP_AHRS: prevent a infinity value 2014-04-21 15:37:07 +10:00
Andrew Tridgell b7350118a6 AP_AHRS: enable EKF wind estimate with no airspeed sensor
EKF can now estimate with IMU and GPS only

Pair-Programmed-With: Paul Riseborough <p_riseborough@live.com.au>
2014-04-13 19:42:49 +10:00
Andrew Tridgell 27a3b5fb36 AP_AHRS: fixed wind reporting with EKF and no airspeed sensor
the EKF does not estimate wind without an airspeed sensor
2014-04-10 06:49:23 +10:00
Andrew Tridgell 35c111a63a AP_AHRS: fixed example build 2014-04-01 06:38:25 +11:00
Andrew Tridgell f07e4dee52 AP_AHRS: convert to new GPS API 2014-04-01 06:38:24 +11:00
Andrew Tridgell afab8a9c5b AP_AHRS: fixed example build 2014-03-19 12:14:02 +09:00
Randy Mackay efd4058e8b AHRS: interate move of p1 from Location to mission cmd 2014-03-19 12:10:51 +09:00
Paul Riseborough 15a44571c2 AP_NavEKF : enable operation without a compass for planes 2014-03-09 20:01:45 +11:00
Andrew Tridgell aaaae9a222 AP_AHRS: added get_fly_forward() method
will be used to detect a copter
2014-02-27 17:39:49 +11:00
Andrew Tridgell 9a5ecc9541 AP_AHRS: use primary accel for accel_ef
Logs from Randy show that the copter INav code can't handle the
accelerometer sensor changing.
2014-02-27 16:28:37 +11:00
Andrew Tridgell b53496d470 AP_AHRS: choose the best accelerometer at each drift correction step
this greatly reduces the impact of aliasing on accelerometers by
choosing the accelerometer that produces the smallest error term in
DCM. The difference can be quite dramatic on the Pixhawk.
2014-02-27 09:41:28 +11:00
Andrew Tridgell 0b45d2bc06 AP_AHRS: removed the AHRS_GPS_DELAY parameter
the best value has turned out to be 1, and tweaking it has not turned
out to be useful, so this simplifies the code in preparation for
adding the anti-aliasing handling with multiple accelerometers
2014-02-27 08:57:44 +11:00
Andrew Tridgell 6fc5c12f1d AP_AHRS: remove unused variable 2014-02-26 10:28:12 +11:00
Jonathan Challinger f321a5f241 AP_AHRS: Change airspeed_estimate to const in children of AP_AHRS
Allows roll/pitch controllers to use DCM's airspeed estimate. Thanks to Kevin Hester for assistance in finding this.
2014-02-25 18:49:16 +11:00
Paul Riseborough 9f3c19c03a AP_AHRS : change initialisation requirements for EKF and use dynamic method 2014-02-23 19:50:34 +11:00
Andrew Tridgell b434c11215 AP_AHRS: removed empty file 2014-02-19 22:00:25 +11:00
Andrew Tridgell 3b1f9a4bbf AP_AHRS: added get_armed() and set_armed() calls
will be used by NavEKF to determine static mode
2014-02-19 10:52:24 +11:00
Andrew Tridgell fad0b2b233 AP_AHRS: added get_correct_centrifugal()
used by NavEKF to force static mode
2014-02-19 10:28:14 +11:00
Andrew Tridgell ee37bc3d27 AP_AHRS: ensure we have HAL_CPU_CLASS available 2014-02-16 17:57:09 +11:00
Randy Mackay a021d0ca31 AHRS: fix compiler warning 2014-02-16 13:35:37 +11:00
Andrew Tridgell be33a9634e AP_AHRS: move using_EKF to .cpp to make it easier in gdb 2014-02-15 09:25:40 +11:00
Andrew Tridgell eedd88c2ec AP_AHRS: give zero lat/lng and baro alt if no position yet in DCM 2014-02-15 09:25:40 +11:00
Randy Mackay 5bdc564191 AP_AHRS: fix example sketch 2014-02-15 06:09:08 +11:00
Andrew Tridgell 801ceacaf2 AP_AHRS: re-run update_trig() after EKF AHRS update 2014-02-15 05:48:24 +11:00
Andrew Tridgell 25ef0d5a7b AP_AHRS: don't allow get_velocity_NED() and get_relative_position_NED() without EKF
this avoids some linking issues, plus the functions are inaccurate
without EKF
2014-02-15 05:48:24 +11:00
Andrew Tridgell c62ccce9d8 AP_AHRS: make estimate_wind() public
this avoids it linking into copter
2014-02-15 05:48:24 +11:00
Andrew Tridgell f09ae0c2d0 AP_AHRS: expose get_NavEKF as non-const
better than having two methods
2014-02-15 05:48:22 +11:00
Paul Riseborough 08267cea87 AP_AHRS: Scheduling for yaw gain to reduce atitude errors in turning flight 2014-02-15 05:48:22 +11:00
Paul Riseborough b4171853b1 AP_NavEKF: allow initialisation before GPS lock to aid indoor testing 2014-02-15 05:48:21 +11:00
Paul Riseborough 0599817aa9 AP_AHRS : EKF initialisation changed to use bootstrap method 2014-02-15 05:48:21 +11:00
Randy Mackay f068d0ff7e AP_AHRS_NavEKF: expose non-const EKF for tuning 2014-02-15 05:48:20 +11:00
Randy Mackay 9f130b40a0 AP_AHRS_NavEKF: override set_correct_centrifugal 2014-02-15 05:48:20 +11:00
Randy Mackay 8f6fd86f69 AP_AHRS: make set_correct_centrifugal virtual 2014-02-15 05:48:20 +11:00
Paul Riseborough a87df0ad56 AP_AHRS : set NavEKF staticMode using call to set_correct_centrigual 2014-02-15 05:48:20 +11:00
Paul Riseborough ab08a5c7d6 AP_AHRS : altered NavEKF set home to reset position instead of reset filter 2014-02-15 05:48:18 +11:00
Andrew Tridgell 574946f0aa AP_AHRS: start EKF 5 seconds after getting GPS lock 2014-02-15 05:48:17 +11:00
Andrew Tridgell df271fbd59 AP_AHRS: fill in _dcm_matrix whenever EKF started
this ensures get_dcm_matrix() always returns valid data
2014-02-15 05:48:17 +11:00
Andrew Tridgell ada7d4fb98 AP_AHRS: use the right DCM matrix when EKF not enabled 2014-02-15 05:48:17 +11:00
Andrew Tridgell a74fcc5a93 AP_AHRS: added set_ekf_use() 2014-02-15 05:48:17 +11:00
Andrew Tridgell 5d43a1d704 AP_AHRS: added inertial nav interfaces to AHRS 2014-02-15 05:48:16 +11:00
Andrew Tridgell 392995ef84 AP_AHRS: make AHRS handle altitude
AHRS now holds the home position
2014-02-15 05:29:47 +11:00
Andrew Tridgell 1e476e511a AP_AHRS: pass baro into AP_AHRS
first step in making AHRS handle altitude
2014-02-15 05:29:47 +11:00
Andrew Tridgell 6e5077b60b AP_AHRS: removed unused AP_AHRS_HIL 2014-02-15 05:29:46 +11:00
Andrew Tridgell 84c7b0d7fd AP_AHRS: check for NavEKF health 2014-02-15 05:29:46 +11:00
Andrew Tridgell b39a5062e9 AP_AHRS: use NavEKF for ground vector when available 2014-02-15 05:29:45 +11:00
Andrew Tridgell b6bc50051f AP_AHRS: allow reporting of secondary AHRS solution 2014-02-15 05:29:45 +11:00
Andrew Tridgell 8c5cde4efd AP_AHRS: allow NavEKF to be enabled at runtime with AHRS_EKF_USE=1 2014-02-15 05:28:10 +11:00
Andrew Tridgell 7ac78ff991 AP_AHRS: create AP_AHRS_NavEKF class
subclass of AP_AHRS_DCM, just a wrapper for now, will add EKF calls
next
2014-02-15 05:28:09 +11:00
Andrew Tridgell c7533579ac AP_AHRS: added get_airspeed() interface to AHRS 2014-02-15 05:28:07 +11:00
Randy Mackay 98d667c916 AHRS_HIL: call update_trig 2014-02-08 18:16:44 +09:00
Randy Mackay 6946d68318 AHRS_DCM: call update_trig 2014-02-08 18:16:42 +09:00
Randy Mackay 3dc6ea682c AHRS: add update_trig
Calculates helper trig values including cos_roll, cos_pitch
2014-02-08 18:16:39 +09:00
Paul Riseborough f2c2811ef3 AP_AHRS & AP_Math: fixed bug in use of AHRS_TRIM parameters 2014-01-19 07:19:43 +11:00
Andrew Tridgell a96840e194 AP_AHRS: changed default GPS lag to 1 sample
this is based on detailed logs from a LEA-6H and NEO-7N
2013-12-30 10:33:48 +11:00
Andrew Tridgell 410d356979 AP_AHRS: make airspeed_estimate const 2013-12-29 18:39:01 +11:00
Michael Day e5addf86c1 AP_AHRS: Added getters for compass and GPS. 2013-12-11 17:29:14 +11:00
Andrew Tridgell baa4ecc2ea APA_AHRS: update for compass API change 2013-12-09 17:34:07 +11:00
Andrew Tridgell b248cc0868 AP_AHRS: fixed a build warning 2013-11-23 21:44:56 +11:00
Andrew Tridgell 710d5119b5 AP_AHRS: added attitude_reset() method for HIL_SENSORS 2013-11-23 19:29:23 +11:00
Andrew Tridgell 6ed493b10f AP_AHRS: added attitude_reset() method for HIL_SENSORS 2013-11-23 18:50:56 +11:00
Andrew Tridgell 4f871c87f1 AP_AHRS: detect and try to cope with bad accels 2013-11-07 13:54:16 +11:00
Andrew Tridgell 56bcda7252 AP_AHRS: lower default roll and yaw drift correction speed
the gyros sustain accuracy over much longer time periods than
previously expected
2013-11-05 14:52:39 +11:00
Andrew Tridgell 02d6f012ce AP_AHRS: added accel sum delay buffer to account for GPS lag 2013-11-04 21:21:42 +11:00
Andrew Tridgell d31e557983 AP_AHRS: save memory and reduce pointer references
use a refence for ins, and don't save gyro and accel between updates
2013-11-04 21:21:37 +11:00