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added full mag fusion

This commit is contained in:
Roman Bapst 2015-12-10 09:07:00 +01:00
parent 8de8b0eb76
commit 67646a15b0
5 changed files with 426 additions and 194 deletions
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2
CMakeLists.txt
View File

@ -47,6 +47,6 @@ px4_add_module(
EKF/ekf_helper.cpp
EKF/covariance.cpp
EKF/vel_pos_fusion.cpp
EKF/heading_fusion.cpp
EKF/mag_fusion.cpp
)
# vim: set noet ft=cmake fenc=utf-8 ff=unix :

25
EKF/ekf.cpp
View File

@ -47,7 +47,8 @@ Ekf::Ekf():
_earth_rate_initialised(false),
_fuse_height(false),
_fuse_pos(false),
_fuse_vel(false)
_fuse_vel(false),
_mag_fuse_index(0)
{
_earth_rate_NED.setZero();
_R_prev = matrix::Dcm<float>();
@ -76,7 +77,9 @@ bool Ekf::update()
// measurement updates
if (_mag_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_mag_sample_delayed)) {
fuseHeading();
//fuseHeading();
fuseMag(_mag_fuse_index);
_mag_fuse_index = (_mag_fuse_index + 1) % 3;
}
if (_baro_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_baro_sample_delayed)) {
@ -197,9 +200,9 @@ void Ekf::printStates()
static int counter = 0;
if (counter % 50 == 0) {
printf("ang error\n");
for(int i = 0; i < 3; i++) {
printf("ang_e %i %.5f\n", i, (double)_state.ang_error(i));
printf("quaternion\n");
for(int i = 0; i < 4; i++) {
printf("quat %i %.5f\n", i, (double)_state.quat_nominal(i));
}
matrix::Euler<float> euler(_state.quat_nominal);
@ -215,20 +218,20 @@ void Ekf::printStates()
printf("p %i %.5f\n", i, (double)_state.pos(i));
}
printf("g gyro_bias\n");
for(int i = 0; i < 3; i++) {
printf("gb %i %.5f\n", i, (double)_state.gyro_bias(i));
}
printf("gyro_scale\n");
for(int i = 0; i < 3; i++) {
printf("gs %i %.5f\n", i, (double)_state.gyro_scale(i));
}
printf("mag_I\n");
printf("mag earth\n");
for(int i = 0; i < 3; i++) {
printf("mI %i %.5f\n", i, (double)_state.mag_I(i));
}
printf("mag bias\n");
for(int i = 0; i < 3; i++) {
printf("mB %i %.5f\n", i, (double)_state.mag_B(i));
}
counter = 0;
}
counter++;

2
EKF/ekf.h
View File

@ -64,6 +64,8 @@ private:
bool _fuse_pos; // true if there is new position data from gps
bool _fuse_vel; // true if there is new velocity data from gps
uint8_t _mag_fuse_index; // counter for sequential mag axis fusion
Vector3f _earth_rate_NED;
matrix::Dcm<float> _R_prev;

182
EKF/heading_fusion.cpp
View File

@ -1,182 +0,0 @@
/****************************************************************************
*
* Copyright (c) 2015 Estimation and Control Library (ECL). All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name ECL nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file heading_fusion.cpp
* Magnetometer heading fusion.
*
* @author Roman Bast <bapstroman@gmail.com>
*
*/
#include "ekf.h"
#include <mathlib/mathlib.h>
void Ekf::fuseHeading()
{
// assign intermediate state variables
float q0 = _state.quat_nominal(0);
float q1 = _state.quat_nominal(1);
float q2 = _state.quat_nominal(2);
float q3 = _state.quat_nominal(3);
float magX = _mag_sample_delayed.mag(0);
float magY = _mag_sample_delayed.mag(1);
float magZ = _mag_sample_delayed.mag(2);
float R_mag = _params.mag_heading_noise;
float t2 = q0*q0;
float t3 = q1*q1;
float t4 = q2*q2;
float t5 = q3*q3;
float t6 = q0*q2*2.0f;
float t7 = q1*q3*2.0f;
float t8 = t6+t7;
float t9 = q0*q3*2.0f;
float t13 = q1*q2*2.0f;
float t10 = t9-t13;
float t11 = t2+t3-t4-t5;
float t12 = magX*t11;
float t14 = magZ*t8;
float t19 = magY*t10;
float t15 = t12+t14-t19;
float t16 = t2-t3+t4-t5;
float t17 = q0*q1*2.0f;
float t24 = q2*q3*2.0f;
float t18 = t17-t24;
float t20 = 1.0f/t15;
float t21 = magY*t16;
float t22 = t9+t13;
float t23 = magX*t22;
float t28 = magZ*t18;
float t25 = t21+t23-t28;
float t29 = t20*t25;
float t26 = tan(t29);
float t27 = 1.0f/(t15*t15);
float t30 = t26*t26;
float t31 = t30+1.0f;
float H_MAG[3] = {};
H_MAG[0] = -t31*(t20*(magZ*t16+magY*t18)+t25*t27*(magY*t8+magZ*t10));
H_MAG[1] = t31*(t20*(magX*t18+magZ*t22)+t25*t27*(magX*t8-magZ*t11));
H_MAG[2] = t31*(t20*(magX*t16-magY*t22)+t25*t27*(magX*t10+magY*t11));
// calculate innovation
matrix::Dcm<float> R_to_earth(_state.quat_nominal);
matrix::Vector3f mag_earth_pred = R_to_earth * _mag_sample_delayed.mag;
float innovation = atan2f(mag_earth_pred(1), mag_earth_pred(0)) - math::radians(_params.mag_declination_deg);
innovation = math::constrain(innovation, -0.5f, 0.5f);
float innovation_var = R_mag;
// calculate innovation variance
float PH[3] = {};
for (unsigned row = 0; row < 3; row++) {
for (unsigned column = 0; column < 3; column++) {
PH[row] += P[row][column]*H_MAG[column];
}
innovation_var += H_MAG[row] * PH[row];
}
if (innovation_var >= R_mag) {
// variance has increased, no failure
_fault_status.bad_mag_x = false;
_fault_status.bad_mag_y = false;
_fault_status.bad_mag_z = false;
} else {
// our innovation variance has decreased, our calculation is thus badly conditioned
_fault_status.bad_mag_x = true;
_fault_status.bad_mag_y = true;
_fault_status.bad_mag_z = true;
// we reinitialise the covariance matrix and abort this fusion step
initialiseCovariance();
return;
}
float innovation_var_inv = 1 / innovation_var;
// calculate kalman gain
float Kfusion[_k_num_states] = {};
for (unsigned row = 0; row < _k_num_states; row++) {
for (unsigned column = 0; column < 3; column++) {
Kfusion[row] += P[row][column] * H_MAG[column];
}
Kfusion[row] *= innovation_var_inv;
}
// innovation test ratio
float yaw_test_ratio = sq(innovation) / (sq(math::max(0.01f * (float)_params.heading_innov_gate, 1.0f)) * innovation_var);
// set the magnetometer unhealthy if the test fails
if (yaw_test_ratio > 1.0f) {
_mag_healthy = false;
// if we are in air we don't want to fuse the measurement
// we allow to use it when on the ground because the large innovation could be caused
// by interference or a large initial gyro bias
if (_in_air) {
return;
}
} else {
_mag_healthy = true;
}
_state.ang_error.setZero();
fuse(Kfusion, innovation);
// correct the nominal quaternion
Quaternion dq;
dq.from_axis_angle(_state.ang_error);
_state.quat_nominal = dq * _state.quat_nominal;
_state.quat_nominal.normalize();
float HP[_k_num_states] = {};
for (unsigned column = 0; column < _k_num_states; column++) {
for (unsigned row = 0; row < 3; row++) {
HP[column] += H_MAG[row] * P[row][column];
}
}
for (unsigned row = 0; row < _k_num_states; row++) {
for (unsigned column = 0; column < _k_num_states; column++) {
P[row][column] -= Kfusion[row] * HP[column];
}
}
makeSymmetrical();
limitCov();
}

409
EKF/mag_fusion.cpp Normal file
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@ -0,0 +1,409 @@
/****************************************************************************
*
* Copyright (c) 2015 Estimation and Control Library (ECL). All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name ECL nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file heading_fusion.cpp
* Magnetometer fusion methods.
*
* @author Roman Bast <bapstroman@gmail.com>
*
*/
#include "ekf.h"
#include <mathlib/mathlib.h>
void Ekf::fuseMag(uint8_t index)
{
// assign intermediate variables
float q0 = _state.quat_nominal(0);
float q1 = _state.quat_nominal(1);
float q2 = _state.quat_nominal(2);
float q3 = _state.quat_nominal(3);
float magN = _state.mag_I(0);
float magE = _state.mag_I(1);
float magD = _state.mag_I(2);
// XXX Measurement uncertainty. Need to consider timing errors for fast rotations
float R_MAG = 1e-3f;
// intermediate variables from algebraic optimisation
float SH_MAG[9];
SH_MAG[0] = sq(q0) - sq(q1) + sq(q2) - sq(q3);
SH_MAG[1] = sq(q0) + sq(q1) - sq(q2) - sq(q3);
SH_MAG[2] = sq(q0) - sq(q1) - sq(q2) + sq(q3);
SH_MAG[3] = 2*q0*q1 + 2*q2*q3;
SH_MAG[4] = 2*q0*q3 + 2*q1*q2;
SH_MAG[5] = 2*q0*q2 + 2*q1*q3;
SH_MAG[6] = magE*(2*q0*q1 - 2*q2*q3);
SH_MAG[7] = 2*q1*q3 - 2*q0*q2;
SH_MAG[8] = 2*q0*q3;
// rotate magnetometer earth field state into body frame
matrix::Dcm<float> R_to_body(_state.quat_nominal);
R_to_body = R_to_body.transpose();
Vector3f mag_I_rot = R_to_body * _state.mag_I;
// compute magnetometer innovations
float mag_innov[3] = {};
mag_innov[0] = (mag_I_rot(0) + _state.mag_B(0)) - _mag_sample_delayed.mag(0);
mag_innov[1] = (mag_I_rot(1) + _state.mag_B(1)) - _mag_sample_delayed.mag(1);
mag_innov[2] = (mag_I_rot(2) + _state.mag_B(2)) - _mag_sample_delayed.mag(2);
// XXX Do mag checks here!
float H_MAG[24] = {};
float Kfusion[24] = {};
// index corresponds to a mag axis (x, y, z)
if (index == 0) {
H_MAG[1] = SH_MAG[6] - magD*SH_MAG[2] - magN*SH_MAG[5];
H_MAG[2] = magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2);
H_MAG[16] = SH_MAG[1];
H_MAG[17] = SH_MAG[4];
H_MAG[18] = SH_MAG[7];
H_MAG[19] = 1;
// intermediate variables
float SK_MX[4] = {};
SK_MX[0] = 1/(P[19][19] + R_MAG - P[1][19]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[16][19]*SH_MAG[1] + P[17][19]*SH_MAG[4] + P[18][19]*SH_MAG[7] + P[2][19]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2)) - (magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5])*(P[19][1] - P[1][1]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[16][1]*SH_MAG[1] + P[17][1]*SH_MAG[4] + P[18][1]*SH_MAG[7] + P[2][1]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2))) + SH_MAG[1]*(P[19][16] - P[1][16]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[16][16]*SH_MAG[1] + P[17][16]*SH_MAG[4] + P[18][16]*SH_MAG[7] + P[2][16]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2))) + SH_MAG[4]*(P[19][17] - P[1][17]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[16][17]*SH_MAG[1] + P[17][17]*SH_MAG[4] + P[18][17]*SH_MAG[7] + P[2][17]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2))) + SH_MAG[7]*(P[19][18] - P[1][18]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[16][18]*SH_MAG[1] + P[17][18]*SH_MAG[4] + P[18][18]*SH_MAG[7] + P[2][18]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2))) + (magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2))*(P[19][2] - P[1][2]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[16][2]*SH_MAG[1] + P[17][2]*SH_MAG[4] + P[18][2]*SH_MAG[7] + P[2][2]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2))));
SK_MX[1] = magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2);
SK_MX[2] = magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5];
SK_MX[3] = SH_MAG[7];
Kfusion[0] = SK_MX[0]*(P[0][19] + P[0][16]*SH_MAG[1] + P[0][17]*SH_MAG[4] - P[0][1]*SK_MX[2] + P[0][2]*SK_MX[1] + P[0][18]*SK_MX[3]);
Kfusion[1] = SK_MX[0]*(P[1][19] + P[1][16]*SH_MAG[1] + P[1][17]*SH_MAG[4] - P[1][1]*SK_MX[2] + P[1][2]*SK_MX[1] + P[1][18]*SK_MX[3]);
Kfusion[2] = SK_MX[0]*(P[2][19] + P[2][16]*SH_MAG[1] + P[2][17]*SH_MAG[4] - P[2][1]*SK_MX[2] + P[2][2]*SK_MX[1] + P[2][18]*SK_MX[3]);
Kfusion[3] = SK_MX[0]*(P[3][19] + P[3][16]*SH_MAG[1] + P[3][17]*SH_MAG[4] - P[3][1]*SK_MX[2] + P[3][2]*SK_MX[1] + P[3][18]*SK_MX[3]);
Kfusion[4] = SK_MX[0]*(P[4][19] + P[4][16]*SH_MAG[1] + P[4][17]*SH_MAG[4] - P[4][1]*SK_MX[2] + P[4][2]*SK_MX[1] + P[4][18]*SK_MX[3]);
Kfusion[5] = SK_MX[0]*(P[5][19] + P[5][16]*SH_MAG[1] + P[5][17]*SH_MAG[4] - P[5][1]*SK_MX[2] + P[5][2]*SK_MX[1] + P[5][18]*SK_MX[3]);
Kfusion[6] = SK_MX[0]*(P[6][19] + P[6][16]*SH_MAG[1] + P[6][17]*SH_MAG[4] - P[6][1]*SK_MX[2] + P[6][2]*SK_MX[1] + P[6][18]*SK_MX[3]);
Kfusion[7] = SK_MX[0]*(P[7][19] + P[7][16]*SH_MAG[1] + P[7][17]*SH_MAG[4] - P[7][1]*SK_MX[2] + P[7][2]*SK_MX[1] + P[7][18]*SK_MX[3]);
Kfusion[8] = SK_MX[0]*(P[8][19] + P[8][16]*SH_MAG[1] + P[8][17]*SH_MAG[4] - P[8][1]*SK_MX[2] + P[8][2]*SK_MX[1] + P[8][18]*SK_MX[3]);
Kfusion[9] = SK_MX[0]*(P[9][19] + P[9][16]*SH_MAG[1] + P[9][17]*SH_MAG[4] - P[9][1]*SK_MX[2] + P[9][2]*SK_MX[1] + P[9][18]*SK_MX[3]);
Kfusion[10] = SK_MX[0]*(P[10][19] + P[10][16]*SH_MAG[1] + P[10][17]*SH_MAG[4] - P[10][1]*SK_MX[2] + P[10][2]*SK_MX[1] + P[10][18]*SK_MX[3]);
Kfusion[11] = SK_MX[0]*(P[11][19] + P[11][16]*SH_MAG[1] + P[11][17]*SH_MAG[4] - P[11][1]*SK_MX[2] + P[11][2]*SK_MX[1] + P[11][18]*SK_MX[3]);
Kfusion[12] = SK_MX[0]*(P[12][19] + P[12][16]*SH_MAG[1] + P[12][17]*SH_MAG[4] - P[12][1]*SK_MX[2] + P[12][2]*SK_MX[1] + P[12][18]*SK_MX[3]);
Kfusion[13] = SK_MX[0]*(P[13][19] + P[13][16]*SH_MAG[1] + P[13][17]*SH_MAG[4] - P[13][1]*SK_MX[2] + P[13][2]*SK_MX[1] + P[13][18]*SK_MX[3]);
Kfusion[14] = SK_MX[0]*(P[14][19] + P[14][16]*SH_MAG[1] + P[14][17]*SH_MAG[4] - P[14][1]*SK_MX[2] + P[14][2]*SK_MX[1] + P[14][18]*SK_MX[3]);
Kfusion[15] = SK_MX[0]*(P[15][19] + P[15][16]*SH_MAG[1] + P[15][17]*SH_MAG[4] - P[15][1]*SK_MX[2] + P[15][2]*SK_MX[1] + P[15][18]*SK_MX[3]);
Kfusion[16] = SK_MX[0]*(P[16][19] + P[16][16]*SH_MAG[1] + P[16][17]*SH_MAG[4] - P[16][1]*SK_MX[2] + P[16][2]*SK_MX[1] + P[16][18]*SK_MX[3]);
Kfusion[17] = SK_MX[0]*(P[17][19] + P[17][16]*SH_MAG[1] + P[17][17]*SH_MAG[4] - P[17][1]*SK_MX[2] + P[17][2]*SK_MX[1] + P[17][18]*SK_MX[3]);
Kfusion[18] = SK_MX[0]*(P[18][19] + P[18][16]*SH_MAG[1] + P[18][17]*SH_MAG[4] - P[18][1]*SK_MX[2] + P[18][2]*SK_MX[1] + P[18][18]*SK_MX[3]);
Kfusion[19] = SK_MX[0]*(P[19][19] + P[19][16]*SH_MAG[1] + P[19][17]*SH_MAG[4] - P[19][1]*SK_MX[2] + P[19][2]*SK_MX[1] + P[19][18]*SK_MX[3]);
Kfusion[20] = SK_MX[0]*(P[20][19] + P[20][16]*SH_MAG[1] + P[20][17]*SH_MAG[4] - P[20][1]*SK_MX[2] + P[20][2]*SK_MX[1] + P[20][18]*SK_MX[3]);
Kfusion[21] = SK_MX[0]*(P[21][19] + P[21][16]*SH_MAG[1] + P[21][17]*SH_MAG[4] - P[21][1]*SK_MX[2] + P[21][2]*SK_MX[1] + P[21][18]*SK_MX[3]);
Kfusion[22] = SK_MX[0]*(P[22][19] + P[22][16]*SH_MAG[1] + P[22][17]*SH_MAG[4] - P[22][1]*SK_MX[2] + P[22][2]*SK_MX[1] + P[22][18]*SK_MX[3]);
Kfusion[23] = SK_MX[0]*(P[23][19] + P[23][16]*SH_MAG[1] + P[23][17]*SH_MAG[4] - P[23][1]*SK_MX[2] + P[23][2]*SK_MX[1] + P[23][18]*SK_MX[3]);
} else if (index == 1) {
H_MAG[0] = magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5];
H_MAG[2] = - magE*SH_MAG[4] - magD*SH_MAG[7] - magN*SH_MAG[1];
H_MAG[16] = 2*q1*q2 - SH_MAG[8];
H_MAG[17] = SH_MAG[0];
H_MAG[18] = SH_MAG[3];
H_MAG[20] = 1;
// intermediate variables - note SK_MY[0] is 1/(innovation variance)
float SK_MY[4];
SK_MY[0] = 1/(P[20][20] + R_MAG + P[0][20]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[17][20]*SH_MAG[0] + P[18][20]*SH_MAG[3] - (SH_MAG[8] - 2*q1*q2)*(P[20][16] + P[0][16]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[17][16]*SH_MAG[0] + P[18][16]*SH_MAG[3] - P[2][16]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) - P[16][16]*(SH_MAG[8] - 2*q1*q2)) - P[2][20]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) + (magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5])*(P[20][0] + P[0][0]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[17][0]*SH_MAG[0] + P[18][0]*SH_MAG[3] - P[2][0]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) - P[16][0]*(SH_MAG[8] - 2*q1*q2)) + SH_MAG[0]*(P[20][17] + P[0][17]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[17][17]*SH_MAG[0] + P[18][17]*SH_MAG[3] - P[2][17]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) - P[16][17]*(SH_MAG[8] - 2*q1*q2)) + SH_MAG[3]*(P[20][18] + P[0][18]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[17][18]*SH_MAG[0] + P[18][18]*SH_MAG[3] - P[2][18]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) - P[16][18]*(SH_MAG[8] - 2*q1*q2)) - P[16][20]*(SH_MAG[8] - 2*q1*q2) - (magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1])*(P[20][2] + P[0][2]*(magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5]) + P[17][2]*SH_MAG[0] + P[18][2]*SH_MAG[3] - P[2][2]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) - P[16][2]*(SH_MAG[8] - 2*q1*q2)));
SK_MY[1] = magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1];
SK_MY[2] = magD*SH_MAG[2] - SH_MAG[6] + magN*SH_MAG[5];
SK_MY[3] = SH_MAG[8] - 2*q1*q2;
Kfusion[0] = SK_MY[0]*(P[0][20] + P[0][17]*SH_MAG[0] + P[0][18]*SH_MAG[3] + P[0][0]*SK_MY[2] - P[0][2]*SK_MY[1] - P[0][16]*SK_MY[3]);
Kfusion[1] = SK_MY[0]*(P[1][20] + P[1][17]*SH_MAG[0] + P[1][18]*SH_MAG[3] + P[1][0]*SK_MY[2] - P[1][2]*SK_MY[1] - P[1][16]*SK_MY[3]);
Kfusion[2] = SK_MY[0]*(P[2][20] + P[2][17]*SH_MAG[0] + P[2][18]*SH_MAG[3] + P[2][0]*SK_MY[2] - P[2][2]*SK_MY[1] - P[2][16]*SK_MY[3]);
Kfusion[3] = SK_MY[0]*(P[3][20] + P[3][17]*SH_MAG[0] + P[3][18]*SH_MAG[3] + P[3][0]*SK_MY[2] - P[3][2]*SK_MY[1] - P[3][16]*SK_MY[3]);
Kfusion[4] = SK_MY[0]*(P[4][20] + P[4][17]*SH_MAG[0] + P[4][18]*SH_MAG[3] + P[4][0]*SK_MY[2] - P[4][2]*SK_MY[1] - P[4][16]*SK_MY[3]);
Kfusion[5] = SK_MY[0]*(P[5][20] + P[5][17]*SH_MAG[0] + P[5][18]*SH_MAG[3] + P[5][0]*SK_MY[2] - P[5][2]*SK_MY[1] - P[5][16]*SK_MY[3]);
Kfusion[6] = SK_MY[0]*(P[6][20] + P[6][17]*SH_MAG[0] + P[6][18]*SH_MAG[3] + P[6][0]*SK_MY[2] - P[6][2]*SK_MY[1] - P[6][16]*SK_MY[3]);
Kfusion[7] = SK_MY[0]*(P[7][20] + P[7][17]*SH_MAG[0] + P[7][18]*SH_MAG[3] + P[7][0]*SK_MY[2] - P[7][2]*SK_MY[1] - P[7][16]*SK_MY[3]);
Kfusion[8] = SK_MY[0]*(P[8][20] + P[8][17]*SH_MAG[0] + P[8][18]*SH_MAG[3] + P[8][0]*SK_MY[2] - P[8][2]*SK_MY[1] - P[8][16]*SK_MY[3]);
Kfusion[9] = SK_MY[0]*(P[9][20] + P[9][17]*SH_MAG[0] + P[9][18]*SH_MAG[3] + P[9][0]*SK_MY[2] - P[9][2]*SK_MY[1] - P[9][16]*SK_MY[3]);
Kfusion[10] = SK_MY[0]*(P[10][20] + P[10][17]*SH_MAG[0] + P[10][18]*SH_MAG[3] + P[10][0]*SK_MY[2] - P[10][2]*SK_MY[1] - P[10][16]*SK_MY[3]);
Kfusion[11] = SK_MY[0]*(P[11][20] + P[11][17]*SH_MAG[0] + P[11][18]*SH_MAG[3] + P[11][0]*SK_MY[2] - P[11][2]*SK_MY[1] - P[11][16]*SK_MY[3]);
Kfusion[12] = SK_MY[0]*(P[12][20] + P[12][17]*SH_MAG[0] + P[12][18]*SH_MAG[3] + P[12][0]*SK_MY[2] - P[12][2]*SK_MY[1] - P[12][16]*SK_MY[3]);
Kfusion[13] = SK_MY[0]*(P[13][20] + P[13][17]*SH_MAG[0] + P[13][18]*SH_MAG[3] + P[13][0]*SK_MY[2] - P[13][2]*SK_MY[1] - P[13][16]*SK_MY[3]);
Kfusion[14] = SK_MY[0]*(P[14][20] + P[14][17]*SH_MAG[0] + P[14][18]*SH_MAG[3] + P[14][0]*SK_MY[2] - P[14][2]*SK_MY[1] - P[14][16]*SK_MY[3]);
Kfusion[15] = SK_MY[0]*(P[15][20] + P[15][17]*SH_MAG[0] + P[15][18]*SH_MAG[3] + P[15][0]*SK_MY[2] - P[15][2]*SK_MY[1] - P[15][16]*SK_MY[3]);
Kfusion[16] = SK_MY[0]*(P[16][20] + P[16][17]*SH_MAG[0] + P[16][18]*SH_MAG[3] + P[16][0]*SK_MY[2] - P[16][2]*SK_MY[1] - P[16][16]*SK_MY[3]);
Kfusion[17] = SK_MY[0]*(P[17][20] + P[17][17]*SH_MAG[0] + P[17][18]*SH_MAG[3] + P[17][0]*SK_MY[2] - P[17][2]*SK_MY[1] - P[17][16]*SK_MY[3]);
Kfusion[18] = SK_MY[0]*(P[18][20] + P[18][17]*SH_MAG[0] + P[18][18]*SH_MAG[3] + P[18][0]*SK_MY[2] - P[18][2]*SK_MY[1] - P[18][16]*SK_MY[3]);
Kfusion[19] = SK_MY[0]*(P[19][20] + P[19][17]*SH_MAG[0] + P[19][18]*SH_MAG[3] + P[19][0]*SK_MY[2] - P[19][2]*SK_MY[1] - P[19][16]*SK_MY[3]);
Kfusion[20] = SK_MY[0]*(P[20][20] + P[20][17]*SH_MAG[0] + P[20][18]*SH_MAG[3] + P[20][0]*SK_MY[2] - P[20][2]*SK_MY[1] - P[20][16]*SK_MY[3]);
Kfusion[21] = SK_MY[0]*(P[21][20] + P[21][17]*SH_MAG[0] + P[21][18]*SH_MAG[3] + P[21][0]*SK_MY[2] - P[21][2]*SK_MY[1] - P[21][16]*SK_MY[3]);
Kfusion[22] = SK_MY[0]*(P[22][20] + P[22][17]*SH_MAG[0] + P[22][18]*SH_MAG[3] + P[22][0]*SK_MY[2] - P[22][2]*SK_MY[1] - P[22][16]*SK_MY[3]);
Kfusion[23] = SK_MY[0]*(P[23][20] + P[23][17]*SH_MAG[0] + P[23][18]*SH_MAG[3] + P[23][0]*SK_MY[2] - P[23][2]*SK_MY[1] - P[23][16]*SK_MY[3]);
} else if (index == 2)
{
H_MAG[0] = magN*(SH_MAG[8] - 2*q1*q2) - magD*SH_MAG[3] - magE*SH_MAG[0];
H_MAG[1] = magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1];
H_MAG[16] = SH_MAG[5];
H_MAG[17] = 2*q2*q3 - 2*q0*q1;
H_MAG[18] = SH_MAG[2];
H_MAG[21] = 1;
// intermediate variables
float SK_MZ[4];
SK_MZ[0] = 1/(P[21][21] + R_MAG + P[16][21]*SH_MAG[5] + P[18][21]*SH_MAG[2] - (2*q0*q1 - 2*q2*q3)*(P[21][17] + P[16][17]*SH_MAG[5] + P[18][17]*SH_MAG[2] - P[0][17]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2)) + P[1][17]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) - P[17][17]*(2*q0*q1 - 2*q2*q3)) - P[0][21]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2)) + P[1][21]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) + SH_MAG[5]*(P[21][16] + P[16][16]*SH_MAG[5] + P[18][16]*SH_MAG[2] - P[0][16]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2)) + P[1][16]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) - P[17][16]*(2*q0*q1 - 2*q2*q3)) + SH_MAG[2]*(P[21][18] + P[16][18]*SH_MAG[5] + P[18][18]*SH_MAG[2] - P[0][18]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2)) + P[1][18]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) - P[17][18]*(2*q0*q1 - 2*q2*q3)) - (magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2))*(P[21][0] + P[16][0]*SH_MAG[5] + P[18][0]*SH_MAG[2] - P[0][0]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2)) + P[1][0]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) - P[17][0]*(2*q0*q1 - 2*q2*q3)) - P[17][21]*(2*q0*q1 - 2*q2*q3) + (magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1])*(P[21][1] + P[16][1]*SH_MAG[5] + P[18][1]*SH_MAG[2] - P[0][1]*(magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2)) + P[1][1]*(magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1]) - P[17][1]*(2*q0*q1 - 2*q2*q3)));
SK_MZ[1] = magE*SH_MAG[0] + magD*SH_MAG[3] - magN*(SH_MAG[8] - 2*q1*q2);
SK_MZ[2] = magE*SH_MAG[4] + magD*SH_MAG[7] + magN*SH_MAG[1];
SK_MZ[3] = 2*q0*q1 - 2*q2*q3;
Kfusion[0] = SK_MZ[0]*(P[0][21] + P[0][18]*SH_MAG[2] + P[0][16]*SH_MAG[5] - P[0][0]*SK_MZ[1] + P[0][1]*SK_MZ[2] - P[0][17]*SK_MZ[3]);
Kfusion[1] = SK_MZ[0]*(P[1][21] + P[1][18]*SH_MAG[2] + P[1][16]*SH_MAG[5] - P[1][0]*SK_MZ[1] + P[1][1]*SK_MZ[2] - P[1][17]*SK_MZ[3]);
Kfusion[2] = SK_MZ[0]*(P[2][21] + P[2][18]*SH_MAG[2] + P[2][16]*SH_MAG[5] - P[2][0]*SK_MZ[1] + P[2][1]*SK_MZ[2] - P[2][17]*SK_MZ[3]);
Kfusion[3] = SK_MZ[0]*(P[3][21] + P[3][18]*SH_MAG[2] + P[3][16]*SH_MAG[5] - P[3][0]*SK_MZ[1] + P[3][1]*SK_MZ[2] - P[3][17]*SK_MZ[3]);
Kfusion[4] = SK_MZ[0]*(P[4][21] + P[4][18]*SH_MAG[2] + P[4][16]*SH_MAG[5] - P[4][0]*SK_MZ[1] + P[4][1]*SK_MZ[2] - P[4][17]*SK_MZ[3]);
Kfusion[5] = SK_MZ[0]*(P[5][21] + P[5][18]*SH_MAG[2] + P[5][16]*SH_MAG[5] - P[5][0]*SK_MZ[1] + P[5][1]*SK_MZ[2] - P[5][17]*SK_MZ[3]);
Kfusion[6] = SK_MZ[0]*(P[6][21] + P[6][18]*SH_MAG[2] + P[6][16]*SH_MAG[5] - P[6][0]*SK_MZ[1] + P[6][1]*SK_MZ[2] - P[6][17]*SK_MZ[3]);
Kfusion[7] = SK_MZ[0]*(P[7][21] + P[7][18]*SH_MAG[2] + P[7][16]*SH_MAG[5] - P[7][0]*SK_MZ[1] + P[7][1]*SK_MZ[2] - P[7][17]*SK_MZ[3]);
Kfusion[8] = SK_MZ[0]*(P[8][21] + P[8][18]*SH_MAG[2] + P[8][16]*SH_MAG[5] - P[8][0]*SK_MZ[1] + P[8][1]*SK_MZ[2] - P[8][17]*SK_MZ[3]);
Kfusion[9] = SK_MZ[0]*(P[9][21] + P[9][18]*SH_MAG[2] + P[9][16]*SH_MAG[5] - P[9][0]*SK_MZ[1] + P[9][1]*SK_MZ[2] - P[9][17]*SK_MZ[3]);
Kfusion[10] = SK_MZ[0]*(P[10][21] + P[10][18]*SH_MAG[2] + P[10][16]*SH_MAG[5] - P[10][0]*SK_MZ[1] + P[10][1]*SK_MZ[2] - P[10][17]*SK_MZ[3]);
Kfusion[11] = SK_MZ[0]*(P[11][21] + P[11][18]*SH_MAG[2] + P[11][16]*SH_MAG[5] - P[11][0]*SK_MZ[1] + P[11][1]*SK_MZ[2] - P[11][17]*SK_MZ[3]);
Kfusion[12] = SK_MZ[0]*(P[12][21] + P[12][18]*SH_MAG[2] + P[12][16]*SH_MAG[5] - P[12][0]*SK_MZ[1] + P[12][1]*SK_MZ[2] - P[12][17]*SK_MZ[3]);
Kfusion[13] = SK_MZ[0]*(P[13][21] + P[13][18]*SH_MAG[2] + P[13][16]*SH_MAG[5] - P[13][0]*SK_MZ[1] + P[13][1]*SK_MZ[2] - P[13][17]*SK_MZ[3]);
Kfusion[14] = SK_MZ[0]*(P[14][21] + P[14][18]*SH_MAG[2] + P[14][16]*SH_MAG[5] - P[14][0]*SK_MZ[1] + P[14][1]*SK_MZ[2] - P[14][17]*SK_MZ[3]);
Kfusion[15] = SK_MZ[0]*(P[15][21] + P[15][18]*SH_MAG[2] + P[15][16]*SH_MAG[5] - P[15][0]*SK_MZ[1] + P[15][1]*SK_MZ[2] - P[15][17]*SK_MZ[3]);
Kfusion[16] = SK_MZ[0]*(P[16][21] + P[16][18]*SH_MAG[2] + P[16][16]*SH_MAG[5] - P[16][0]*SK_MZ[1] + P[16][1]*SK_MZ[2] - P[16][17]*SK_MZ[3]);
Kfusion[17] = SK_MZ[0]*(P[17][21] + P[17][18]*SH_MAG[2] + P[17][16]*SH_MAG[5] - P[17][0]*SK_MZ[1] + P[17][1]*SK_MZ[2] - P[17][17]*SK_MZ[3]);
Kfusion[18] = SK_MZ[0]*(P[18][21] + P[18][18]*SH_MAG[2] + P[18][16]*SH_MAG[5] - P[18][0]*SK_MZ[1] + P[18][1]*SK_MZ[2] - P[18][17]*SK_MZ[3]);
Kfusion[19] = SK_MZ[0]*(P[19][21] + P[19][18]*SH_MAG[2] + P[19][16]*SH_MAG[5] - P[19][0]*SK_MZ[1] + P[19][1]*SK_MZ[2] - P[19][17]*SK_MZ[3]);
Kfusion[20] = SK_MZ[0]*(P[20][21] + P[20][18]*SH_MAG[2] + P[20][16]*SH_MAG[5] - P[20][0]*SK_MZ[1] + P[20][1]*SK_MZ[2] - P[20][17]*SK_MZ[3]);
Kfusion[21] = SK_MZ[0]*(P[21][21] + P[21][18]*SH_MAG[2] + P[21][16]*SH_MAG[5] - P[21][0]*SK_MZ[1] + P[21][1]*SK_MZ[2] - P[21][17]*SK_MZ[3]);
Kfusion[22] = SK_MZ[0]*(P[22][21] + P[22][18]*SH_MAG[2] + P[22][16]*SH_MAG[5] - P[22][0]*SK_MZ[1] + P[22][1]*SK_MZ[2] - P[22][17]*SK_MZ[3]);
Kfusion[23] = SK_MZ[0]*(P[23][21] + P[23][18]*SH_MAG[2] + P[23][16]*SH_MAG[5] - P[23][0]*SK_MZ[1] + P[23][1]*SK_MZ[2] - P[23][17]*SK_MZ[3]);
} else {
}
// by definition our error state is zero at the time of fusion
_state.ang_error.setZero();
fuse(Kfusion, mag_innov[index]);
Quaternion q_correction;
q_correction.from_axis_angle(_state.ang_error);
_state.quat_nominal = q_correction * _state.quat_nominal;
_state.quat_nominal.normalize();
_state.ang_error.setZero();
// apply covariance correction via P_new = (I -K*H)*P
// first calculate expression for KHP
// then calculate P - KHP
float KH[_k_num_states][_k_num_states] = {};
for (unsigned row = 0; row < _k_num_states; row++) {
for (unsigned column = 0; column < 3; column++) {
KH[row][column] = Kfusion[row] * H_MAG[column];
}
for (unsigned column = 16; column < 22; column++) {
KH[row][column] = Kfusion[row] * H_MAG[column];
}
}
float KHP[_k_num_states][_k_num_states] = {};
for (unsigned row = 0; row < _k_num_states; row++) {
for (unsigned column = 0; column < _k_num_states; column++) {
float tmp = KH[row][0] * P[0][column];
tmp += KH[row][1] * P[1][column];
tmp += KH[row][2] * P[2][column];
tmp += KH[row][16] * P[16][column];
tmp += KH[row][17] * P[17][column];
tmp += KH[row][18] * P[18][column];
tmp += KH[row][19] * P[19][column];
tmp += KH[row][20] * P[20][column];
tmp += KH[row][21] * P[21][column];
KHP[row][column] = tmp;
}
}
for (unsigned row = 0; row < _k_num_states; row++) {
for (unsigned column = 0; column < _k_num_states; column++) {
P[row][column] -= KHP[row][column];
}
}
makeSymmetrical();
limitCov();
}
void Ekf::fuseHeading()
{
// assign intermediate state variables
float q0 = _state.quat_nominal(0);
float q1 = _state.quat_nominal(1);
float q2 = _state.quat_nominal(2);
float q3 = _state.quat_nominal(3);
float magX = _mag_sample_delayed.mag(0);
float magY = _mag_sample_delayed.mag(1);
float magZ = _mag_sample_delayed.mag(2);
float R_mag = _params.mag_heading_noise;
float t2 = q0*q0;
float t3 = q1*q1;
float t4 = q2*q2;
float t5 = q3*q3;
float t6 = q0*q2*2.0f;
float t7 = q1*q3*2.0f;
float t8 = t6+t7;
float t9 = q0*q3*2.0f;
float t13 = q1*q2*2.0f;
float t10 = t9-t13;
float t11 = t2+t3-t4-t5;
float t12 = magX*t11;
float t14 = magZ*t8;
float t19 = magY*t10;
float t15 = t12+t14-t19;
float t16 = t2-t3+t4-t5;
float t17 = q0*q1*2.0f;
float t24 = q2*q3*2.0f;
float t18 = t17-t24;
float t20 = 1.0f/t15;
float t21 = magY*t16;
float t22 = t9+t13;
float t23 = magX*t22;
float t28 = magZ*t18;
float t25 = t21+t23-t28;
float t29 = t20*t25;
float t26 = tan(t29);
float t27 = 1.0f/(t15*t15);
float t30 = t26*t26;
float t31 = t30+1.0f;
float H_MAG[3] = {};
H_MAG[0] = -t31*(t20*(magZ*t16+magY*t18)+t25*t27*(magY*t8+magZ*t10));
H_MAG[1] = t31*(t20*(magX*t18+magZ*t22)+t25*t27*(magX*t8-magZ*t11));
H_MAG[2] = t31*(t20*(magX*t16-magY*t22)+t25*t27*(magX*t10+magY*t11));
// calculate innovation
matrix::Dcm<float> R_to_earth(_state.quat_nominal);
matrix::Vector3f mag_earth_pred = R_to_earth * _mag_sample_delayed.mag;
float innovation = atan2f(mag_earth_pred(1), mag_earth_pred(0)) - math::radians(_params.mag_declination_deg);
innovation = math::constrain(innovation, -0.5f, 0.5f);
float innovation_var = R_mag;
// calculate innovation variance
float PH[3] = {};
for (unsigned row = 0; row < 3; row++) {
for (unsigned column = 0; column < 3; column++) {
PH[row] += P[row][column]*H_MAG[column];
}
innovation_var += H_MAG[row] * PH[row];
}
if (innovation_var >= R_mag) {
// variance has increased, no failure
_fault_status.bad_mag_x = false;
_fault_status.bad_mag_y = false;
_fault_status.bad_mag_z = false;
} else {
// our innovation variance has decreased, our calculation is thus badly conditioned
_fault_status.bad_mag_x = true;
_fault_status.bad_mag_y = true;
_fault_status.bad_mag_z = true;
// we reinitialise the covariance matrix and abort this fusion step
initialiseCovariance();
return;
}
float innovation_var_inv = 1 / innovation_var;
// calculate kalman gain
float Kfusion[_k_num_states] = {};
for (unsigned row = 0; row < _k_num_states; row++) {
for (unsigned column = 0; column < 3; column++) {
Kfusion[row] += P[row][column] * H_MAG[column];
}
Kfusion[row] *= innovation_var_inv;
}
// innovation test ratio
float yaw_test_ratio = sq(innovation) / (sq(math::max(0.01f * (float)_params.heading_innov_gate, 1.0f)) * innovation_var);
// set the magnetometer unhealthy if the test fails
if (yaw_test_ratio > 1.0f) {
_mag_healthy = false;
// if we are in air we don't want to fuse the measurement
// we allow to use it when on the ground because the large innovation could be caused
// by interference or a large initial gyro bias
if (_in_air) {
return;
}
} else {
_mag_healthy = true;
}
_state.ang_error.setZero();
fuse(Kfusion, innovation);
// correct the nominal quaternion
Quaternion dq;
dq.from_axis_angle(_state.ang_error);
_state.quat_nominal = dq * _state.quat_nominal;
_state.quat_nominal.normalize();
float HP[_k_num_states] = {};
for (unsigned column = 0; column < _k_num_states; column++) {
for (unsigned row = 0; row < 3; row++) {
HP[column] += H_MAG[row] * P[row][column];
}
}
for (unsigned row = 0; row < _k_num_states; row++) {
for (unsigned column = 0; column < _k_num_states; column++) {
P[row][column] -= Kfusion[row] * HP[column];
}
}
makeSymmetrical();
limitCov();
}