Compare commits

...

1 Commits

Author SHA1 Message Date
Daniel Agar afb68c1597 ekf2: refactor fuse measurement helpers for consistency
- centralize measurement update methods in ekf.cpp
 - always check if variance calculation is badly conditioned
2024-07-15 11:14:02 -04:00
17 changed files with 194 additions and 190 deletions
@@ -61,12 +61,12 @@ bool ZeroGyroUpdate::update(Ekf &ekf, const estimator::imuSample &imu_delayed)
Vector3f gyro_bias = _zgup_delta_ang / _zgup_delta_ang_dt;
const float obs_var = sq(math::constrain(ekf.getGyroNoise(), 0.f, 1.f));
const float R = sq(math::constrain(ekf.getGyroNoise(), 0.f, 1.f));
for (unsigned i = 0; i < 3; i++) {
const float innovation = ekf.state().gyro_bias(i) - gyro_bias(i);
const float innov_var = ekf.getGyroBiasVariance()(i) + obs_var;
ekf.fuseDirectStateMeasurement(innovation, innov_var, obs_var, State::gyro_bias.idx + i);
const float innov_var = ekf.getGyroBiasVariance()(i) + R;
ekf.fuseDirectStateMeasurement(State::gyro_bias.idx + i, R, innovation, innov_var);
}
// Reset the integrators
@@ -61,12 +61,13 @@ bool ZeroVelocityUpdate::update(Ekf &ekf, const estimator::imuSample &imu_delaye
// Set a low variance initially for faster leveling and higher
// later to let the states follow the measurements
const float obs_var = ekf.control_status_flags().tilt_align ? sq(0.2f) : sq(0.001f);
Vector3f innov_var = ekf.getVelocityVariance() + obs_var;
const float R = ekf.control_status_flags().tilt_align ? sq(0.2f) : sq(0.001f);
for (unsigned i = 0; i < 3; i++) {
const float innovation = ekf.state().vel(i) - vel_obs(i);
ekf.fuseDirectStateMeasurement(innovation, innov_var(i), obs_var, State::vel.idx + i);
const Vector3f innov = ekf.state().vel - vel_obs;
const Vector3f innov_var = ekf.getVelocityVariance() + R;
for (unsigned i = 0; i <= 2; i++) {
ekf.fuseDirectStateMeasurement(State::vel.idx + i, R, innov(i), innov_var(i));
}
_time_last_fuse = imu_delayed.time_us;
@@ -210,7 +210,7 @@ void Ekf::fuseAirspeed(const airspeedSample &airspeed_sample, estimator_aid_sour
K.slice<State::wind_vel.dof, 1>(State::wind_vel.idx, 0) = K_wind;
}
const bool is_fused = measurementUpdate(K, H, aid_src.observation_variance, aid_src.innovation);
const bool is_fused = fuseMeasurement(K, H, aid_src.observation_variance, aid_src.innovation);
aid_src.fused = is_fused;
_fault_status.flags.bad_airspeed = !is_fused;
@@ -159,10 +159,7 @@ void Ekf::fuseDrag(const dragSample &drag_sample)
&& PX4_ISFINITE(innovation_variance(axis_index)) && PX4_ISFINITE(innovation(axis_index))
&& (test_ratio < 1.f)
) {
VectorState K = P * H / innovation_variance(axis_index);
if (measurementUpdate(K, H, R_ACC, innovation(axis_index))) {
if (fuseMeasurement(H, R_ACC, innovation(axis_index), innovation_variance(axis_index))) {
fused[axis_index] = true;
}
}
@@ -278,8 +278,8 @@ bool Ekf::fuseEvVelocity(estimator_aid_source3d_s &aid_src, const extVisionSampl
math::max(_params.ev_vel_innov_gate, 1.f)); // innovation gate
if (!current_aid_src.innovation_rejected) {
fuseBodyVelocity(current_aid_src, current_aid_src.innovation_variance, H);
current_aid_src.fused = fuseMeasurement(H, current_aid_src.observation_variance,
current_aid_src.innovation, current_aid_src.innovation_variance);
}
aid_src.innovation[index] = current_aid_src.innovation;
@@ -115,11 +115,7 @@ void Ekf::fuseGpsYaw(float antenna_yaw_offset)
resetGyroBiasZCov();
}
// calculate the Kalman gains
// only calculate gains for states we are using
VectorState Kfusion = P * H / aid_src.innovation_variance;
const bool is_fused = measurementUpdate(Kfusion, H, aid_src.observation_variance, aid_src.innovation);
const bool is_fused = fuseMeasurement(H, aid_src.observation_variance, aid_src.innovation, aid_src.innovation_variance);
_fault_status.flags.bad_hdg = !is_fused;
aid_src.fused = is_fused;
@@ -103,13 +103,11 @@ void Ekf::controlGravityFusion(const imuSample &imu)
-1.f))(index) - measurement(index);
}
VectorState K = P * H / _aid_src_gravity.innovation_variance[index];
const bool accel_clipping = imu.delta_vel_clipping[0] || imu.delta_vel_clipping[1] || imu.delta_vel_clipping[2];
if (_control_status.flags.gravity_vector && !_aid_src_gravity.innovation_rejected && !accel_clipping) {
fused[index] = measurementUpdate(K, H, _aid_src_gravity.observation_variance[index],
_aid_src_gravity.innovation[index]);
fused[index] = fuseMeasurement(H, _aid_src_gravity.observation_variance[index],
_aid_src_gravity.innovation[index], _aid_src_gravity.innovation_variance[index]);
}
}
@@ -125,7 +125,7 @@ bool Ekf::fuseMag(const Vector3f &mag, const float R_MAG, VectorState &H, estima
Kfusion.slice<State::mag_B.dof, 1>(State::mag_B.idx, 0) = K_mag_B;
}
if (measurementUpdate(Kfusion, H, aid_src.observation_variance[index], aid_src.innovation[index])) {
if (fuseMeasurement(Kfusion, H, aid_src.observation_variance[index], aid_src.innovation[index])) {
fused[index] = true;
}
}
@@ -179,15 +179,7 @@ bool Ekf::fuseDeclination(float decl_sigma)
const float innovation = wrap_pi(decl_pred - decl_measurement);
if (innovation_variance < R_DECL) {
// variance calculation is badly conditioned
return false;
}
// Calculate the Kalman gains
VectorState Kfusion = P * H / innovation_variance;
const bool is_fused = measurementUpdate(Kfusion, H, R_DECL, innovation);
const bool is_fused = fuseMeasurement(H, R_DECL, innovation, innovation_variance);
_fault_status.flags.bad_mag_decl = !is_fused;
@@ -85,8 +85,9 @@ bool Ekf::fuseOptFlow(VectorState &H, const bool update_terrain)
Kfusion(State::terrain.idx) = 0.f;
}
if (measurementUpdate(Kfusion, H, _aid_src_optical_flow.observation_variance[index],
_aid_src_optical_flow.innovation[index])) {
if (fuseMeasurement(Kfusion, H, _aid_src_optical_flow.observation_variance[index],
_aid_src_optical_flow.innovation[index])
) {
fused[index] = true;
}
}
@@ -58,13 +58,13 @@ bool Ekf::fuseHaglRng(estimator_aid_source1d_s &aid_src, bool update_height, boo
K(State::terrain.idx) = k_terrain;
}
measurementUpdate(K, H, aid_src.observation_variance, aid_src.innovation);
if (fuseMeasurement(K, H, aid_src.observation_variance, aid_src.innovation)) {
// record last successful fusion event
_innov_check_fail_status.flags.reject_hagl = false;
// record last successful fusion event
_innov_check_fail_status.flags.reject_hagl = false;
aid_src.time_last_fuse = _time_delayed_us;
aid_src.fused = true;
}
aid_src.time_last_fuse = _time_delayed_us;
aid_src.fused = true;
return true;
return aid_src.fused;
}
@@ -141,12 +141,12 @@ void Ekf::fuseSideslip(estimator_aid_source1d_s &sideslip)
K.slice<State::wind_vel.dof, 1>(State::wind_vel.idx, 0) = K_wind;
}
const bool is_fused = measurementUpdate(K, H, sideslip.observation_variance, sideslip.innovation);
sideslip.fused = is_fused;
_fault_status.flags.bad_sideslip = !is_fused;
if (is_fused) {
if (fuseMeasurement(K, H, sideslip.observation_variance, sideslip.innovation)) {
sideslip.fused = true;
sideslip.time_last_fuse = _time_delayed_us;
_fault_status.flags.bad_sideslip = false;
}
_fault_status.flags.bad_sideslip = !sideslip.fused;
}
+137 -5
View File
@@ -273,6 +273,138 @@ void Ekf::predictState(const imuSample &imu_delayed)
_height_rate_lpf = _height_rate_lpf * (1.0f - alpha_height_rate_lpf) + _state.vel(2) * alpha_height_rate_lpf;
}
bool Ekf::fuseDirectStateMeasurement(const unsigned state_index, const float R, const float innovation,
const float innovation_variance)
{
if (innovation_variance < R) {
// variance calculation is badly conditioned
return false;
}
VectorState K; // Kalman gain vector for any single observation - sequential fusion is used.
// calculate kalman gain K = PHS, where S = 1/innovation variance
for (int row = 0; row < State::size; row++) {
K(row) = P(row, state_index) / innovation_variance;
}
clearInhibitedStateKalmanGains(K);
#if false
// Matrix implementation of the Joseph stabilized covariance update
// This is extremely expensive to compute. Use for debugging purposes only.
auto A = matrix::eye<float, State::size>();
VectorState H;
H(state_index) = 1.f;
A -= K.multiplyByTranspose(H);
P = A * P;
P = P.multiplyByTranspose(A);
const VectorState KR = K * R;
P += KR.multiplyByTranspose(K);
#else
// Efficient implementation of the Joseph stabilized covariance update
// Based on "G. J. Bierman. Factorization Methods for Discrete Sequential Estimation. Academic Press, Dover Publications, New York, 1977, 2006"
// P = (I - K * H) * P * (I - K * H).T + K * R * K.T
// = P_temp * (I - H.T * K.T) + K * R * K.T
// = P_temp - P_temp * H.T * K.T + K * R * K.T
// Step 1: conventional update
// Compute P_temp and store it in P to avoid allocating more memory
// P is symmetric, so PH == H.T * P.T == H.T * P. Taking the row is faster as matrices are row-major
VectorState PH = P.row(state_index);
for (unsigned i = 0; i < State::size; i++) {
for (unsigned j = 0; j < State::size; j++) {
P(i, j) -= K(i) * PH(j); // P is now not symmetric if K is not optimal (e.g.: some gains have been zeroed)
}
}
// Step 2: stabilized update
// P (or "P_temp") is not symmetric so we must take the column
PH = P.col(state_index);
for (unsigned i = 0; i < State::size; i++) {
for (unsigned j = 0; j <= i; j++) {
P(i, j) = P(i, j) - PH(i) * K(j) + K(i) * R * K(j);
P(j, i) = P(i, j);
}
}
#endif
constrainStateVariances();
// apply the state corrections
fuse(K, innovation);
return true;
}
bool Ekf::fuseMeasurement(const VectorState &H, const float R, const float innovation, const float innovation_variance)
{
if (innovation_variance < R) {
// variance calculation is badly conditioned
return false;
}
// calculate the Kalman gains
// only calculate gains for states we are using
VectorState K = P * H / innovation_variance;
return fuseMeasurement(K, H, R, innovation);
}
bool Ekf::fuseMeasurement(VectorState &K, const VectorState &H, const float R, const float innovation)
{
clearInhibitedStateKalmanGains(K);
#if false
// Matrix implementation of the Joseph stabilized covariance update
// This is extremely expensive to compute. Use for debugging purposes only.
auto A = matrix::eye<float, State::size>();
A -= K.multiplyByTranspose(H);
P = A * P;
P = P.multiplyByTranspose(A);
const VectorState KR = K * R;
P += KR.multiplyByTranspose(K);
#else
// Efficient implementation of the Joseph stabilized covariance update
// Based on "G. J. Bierman. Factorization Methods for Discrete Sequential Estimation. Academic Press, Dover Publications, New York, 1977, 2006"
// P = (I - K * H) * P * (I - K * H).T + K * R * K.T
// = P_temp * (I - H.T * K.T) + K * R * K.T
// = P_temp - P_temp * H.T * K.T + K * R * K.T
// Step 1: conventional update
// Compute P_temp and store it in P to avoid allocating more memory
// P is symmetric, so PH == H.T * P.T == H.T * P. Taking the row is faster as matrices are row-major
VectorState PH = P * H; // H is stored as a column vector. H is in fact H.T
for (unsigned i = 0; i < State::size; i++) {
for (unsigned j = 0; j < State::size; j++) {
P(i, j) -= K(i) * PH(j); // P is now not symmetrical if K is not optimal (e.g.: some gains have been zeroed)
}
}
// Step 2: stabilized update
PH = P * H; // H is stored as a column vector. H is in fact H.T
for (unsigned i = 0; i < State::size; i++) {
for (unsigned j = 0; j <= i; j++) {
P(i, j) = P(i, j) - PH(i) * K(j) + K(i) * R * K(j);
P(j, i) = P(i, j);
}
}
#endif
constrainStateVariances();
// apply the state corrections
fuse(K, innovation);
return true;
}
bool Ekf::resetGlobalPosToExternalObservation(double lat_deg, double lon_deg, float accuracy,
uint64_t timestamp_observation)
{
@@ -301,10 +433,10 @@ bool Ekf::resetGlobalPosToExternalObservation(double lat_deg, double lon_deg, fl
pos_corrected += _state.vel.xy() * dt_s;
}
const float obs_var = math::max(sq(accuracy), sq(0.01f));
const float R = math::max(sq(accuracy), sq(0.01f));
const Vector2f innov = Vector2f(_state.pos.xy()) - pos_corrected;
const Vector2f innov_var = Vector2f(getStateVariance<State::pos>()) + obs_var;
const Vector2f innov_var = Vector2f(getStateVariance<State::pos>()) + R;
const float sq_gate = sq(5.f); // magic hardcoded gate
const Vector2f test_ratio{sq(innov(0)) / (sq_gate * innov_var(0)),
@@ -318,13 +450,13 @@ bool Ekf::resetGlobalPosToExternalObservation(double lat_deg, double lon_deg, fl
ECL_INFO("reset position to external observation");
_information_events.flags.reset_pos_to_ext_obs = true;
resetHorizontalPositionTo(pos_corrected, obs_var);
resetHorizontalPositionTo(pos_corrected, R);
_last_known_pos.xy() = _state.pos.xy();
return true;
} else {
if (fuseDirectStateMeasurement(innov(0), innov_var(0), obs_var, State::pos.idx + 0)
&& fuseDirectStateMeasurement(innov(1), innov_var(1), obs_var, State::pos.idx + 1)
if (fuseDirectStateMeasurement(State::pos.idx + 0, R, innov(0), innov_var(0))
&& fuseDirectStateMeasurement(State::pos.idx + 1, R, innov(1), innov_var(1))
) {
ECL_INFO("fused external observation as position measurement");
_time_last_hor_pos_fuse = _time_delayed_us;
+6 -58
View File
@@ -320,8 +320,12 @@ public:
#endif
}
// fuse single direct state measurement (eg NED velocity, NED position, mag earth field, etc)
bool fuseDirectStateMeasurement(const float innov, const float innov_var, const float R, const int state_index);
bool fuseMeasurement(const VectorState &H, const float R, const float innovation, const float innovation_variance);
bool fuseMeasurement(VectorState &K, const VectorState &H, const float R, const float innovation);
// fuse direct state observations
bool fuseDirectStateMeasurement(const unsigned state_index, const float R, const float innovation,
const float innovation_variance);
// gyro bias
const Vector3f &getGyroBias() const { return _state.gyro_bias; } // get the gyroscope bias in rad/s
@@ -471,57 +475,6 @@ public:
const auto &aid_src_aux_vel() const { return _aid_src_aux_vel; }
#endif // CONFIG_EKF2_AUXVEL
bool measurementUpdate(VectorState &K, const VectorState &H, const float R, const float innovation)
{
clearInhibitedStateKalmanGains(K);
#if false
// Matrix implementation of the Joseph stabilized covariance update
// This is extremely expensive to compute. Use for debugging purposes only.
auto A = matrix::eye<float, State::size>();
A -= K.multiplyByTranspose(H);
P = A * P;
P = P.multiplyByTranspose(A);
const VectorState KR = K * R;
P += KR.multiplyByTranspose(K);
#else
// Efficient implementation of the Joseph stabilized covariance update
// Based on "G. J. Bierman. Factorization Methods for Discrete Sequential Estimation. Academic Press, Dover Publications, New York, 1977, 2006"
// P = (I - K * H) * P * (I - K * H).T + K * R * K.T
// = P_temp * (I - H.T * K.T) + K * R * K.T
// = P_temp - P_temp * H.T * K.T + K * R * K.T
// Step 1: conventional update
// Compute P_temp and store it in P to avoid allocating more memory
// P is symmetric, so PH == H.T * P.T == H.T * P. Taking the row is faster as matrices are row-major
VectorState PH = P * H; // H is stored as a column vector. H is in fact H.T
for (unsigned i = 0; i < State::size; i++) {
for (unsigned j = 0; j < State::size; j++) {
P(i, j) -= K(i) * PH(j); // P is now not symmetrical if K is not optimal (e.g.: some gains have been zeroed)
}
}
// Step 2: stabilized update
PH = P * H; // H is stored as a column vector. H is in fact H.T
for (unsigned i = 0; i < State::size; i++) {
for (unsigned j = 0; j <= i; j++) {
P(i, j) = P(i, j) - PH(i) * K(j) + K(i) * R * K(j);
P(j, i) = P(i, j);
}
}
#endif
constrainStateVariances();
// apply the state corrections
fuse(K, innovation);
return true;
}
bool resetGlobalPosToExternalObservation(double lat_deg, double lon_deg, float accuracy,
uint64_t timestamp_observation);
@@ -963,11 +916,6 @@ private:
void stopEvVelFusion();
void stopEvYawFusion();
bool fuseEvVelocity(estimator_aid_source3d_s &aid_src, const extVisionSample &ev_sample);
void fuseBodyVelocity(estimator_aid_source1d_s &aid_src, float &innov_var, VectorState &H)
{
VectorState Kfusion = P * H / innov_var;
aid_src.fused = measurementUpdate(Kfusion, H, aid_src.observation_variance, aid_src.innovation);
}
#endif // CONFIG_EKF2_EXTERNAL_VISION
#if defined(CONFIG_EKF2_GNSS)
-61
View File
@@ -878,64 +878,3 @@ void Ekf::updateIMUBiasInhibit(const imuSample &imu_delayed)
_accel_bias_inhibit[index] = do_inhibit_all_accel_axes || imu_delayed.delta_vel_clipping[index] || !is_bias_observable;
}
}
bool Ekf::fuseDirectStateMeasurement(const float innov, const float innov_var, const float R, const int state_index)
{
VectorState K; // Kalman gain vector for any single observation - sequential fusion is used.
// calculate kalman gain K = PHS, where S = 1/innovation variance
for (int row = 0; row < State::size; row++) {
K(row) = P(row, state_index) / innov_var;
}
clearInhibitedStateKalmanGains(K);
#if false
// Matrix implementation of the Joseph stabilized covariance update
// This is extremely expensive to compute. Use for debugging purposes only.
auto A = matrix::eye<float, State::size>();
VectorState H;
H(state_index) = 1.f;
A -= K.multiplyByTranspose(H);
P = A * P;
P = P.multiplyByTranspose(A);
const VectorState KR = K * R;
P += KR.multiplyByTranspose(K);
#else
// Efficient implementation of the Joseph stabilized covariance update
// Based on "G. J. Bierman. Factorization Methods for Discrete Sequential Estimation. Academic Press, Dover Publications, New York, 1977, 2006"
// P = (I - K * H) * P * (I - K * H).T + K * R * K.T
// = P_temp * (I - H.T * K.T) + K * R * K.T
// = P_temp - P_temp * H.T * K.T + K * R * K.T
// Step 1: conventional update
// Compute P_temp and store it in P to avoid allocating more memory
// P is symmetric, so PH == H.T * P.T == H.T * P. Taking the row is faster as matrices are row-major
VectorState PH = P.row(state_index);
for (unsigned i = 0; i < State::size; i++) {
for (unsigned j = 0; j < State::size; j++) {
P(i, j) -= K(i) * PH(j); // P is now not symmetric if K is not optimal (e.g.: some gains have been zeroed)
}
}
// Step 2: stabilized update
// P (or "P_temp") is not symmetric so we must take the column
PH = P.col(state_index);
for (unsigned i = 0; i < State::size; i++) {
for (unsigned j = 0; j <= i; j++) {
P(i, j) = P(i, j) - PH(i) * K(j) + K(i) * R * K(j);
P(j, i) = P(i, j);
}
}
#endif
constrainStateVariances();
// apply the state corrections
fuse(K, innov);
return true;
}
+6 -6
View File
@@ -57,10 +57,10 @@ bool Ekf::fuseHorizontalPosition(estimator_aid_source2d_s &aid_src)
{
// x & y
if (!aid_src.innovation_rejected
&& fuseDirectStateMeasurement(aid_src.innovation[0], aid_src.innovation_variance[0], aid_src.observation_variance[0],
State::pos.idx + 0)
&& fuseDirectStateMeasurement(aid_src.innovation[1], aid_src.innovation_variance[1], aid_src.observation_variance[1],
State::pos.idx + 1)
&& fuseDirectStateMeasurement(State::pos.idx + 0, aid_src.observation_variance[0], aid_src.innovation[0],
aid_src.innovation_variance[0])
&& fuseDirectStateMeasurement(State::pos.idx + 1, aid_src.observation_variance[1], aid_src.innovation[1],
aid_src.innovation_variance[1])
) {
aid_src.fused = true;
aid_src.time_last_fuse = _time_delayed_us;
@@ -78,8 +78,8 @@ bool Ekf::fuseVerticalPosition(estimator_aid_source1d_s &aid_src)
{
// z
if (!aid_src.innovation_rejected
&& fuseDirectStateMeasurement(aid_src.innovation, aid_src.innovation_variance, aid_src.observation_variance,
State::pos.idx + 2)
&& fuseDirectStateMeasurement(State::pos.idx + 2, aid_src.observation_variance, aid_src.innovation,
aid_src.innovation_variance)
) {
aid_src.fused = true;
aid_src.time_last_fuse = _time_delayed_us;
+10 -10
View File
@@ -37,10 +37,10 @@ bool Ekf::fuseHorizontalVelocity(estimator_aid_source2d_s &aid_src)
{
// vx, vy
if (!aid_src.innovation_rejected
&& fuseDirectStateMeasurement(aid_src.innovation[0], aid_src.innovation_variance[0], aid_src.observation_variance[0],
State::vel.idx + 0)
&& fuseDirectStateMeasurement(aid_src.innovation[1], aid_src.innovation_variance[1], aid_src.observation_variance[1],
State::vel.idx + 1)
&& fuseDirectStateMeasurement(State::vel.idx + 0, aid_src.observation_variance[0], aid_src.innovation[0],
aid_src.innovation_variance[0])
&& fuseDirectStateMeasurement(State::vel.idx + 1, aid_src.observation_variance[1], aid_src.innovation[1],
aid_src.innovation_variance[1])
) {
aid_src.fused = true;
aid_src.time_last_fuse = _time_delayed_us;
@@ -58,12 +58,12 @@ bool Ekf::fuseVelocity(estimator_aid_source3d_s &aid_src)
{
// vx, vy, vz
if (!aid_src.innovation_rejected
&& fuseDirectStateMeasurement(aid_src.innovation[0], aid_src.innovation_variance[0], aid_src.observation_variance[0],
State::vel.idx + 0)
&& fuseDirectStateMeasurement(aid_src.innovation[1], aid_src.innovation_variance[1], aid_src.observation_variance[1],
State::vel.idx + 1)
&& fuseDirectStateMeasurement(aid_src.innovation[2], aid_src.innovation_variance[2], aid_src.observation_variance[2],
State::vel.idx + 2)
&& fuseDirectStateMeasurement(State::vel.idx + 0, aid_src.observation_variance[0], aid_src.innovation[0],
aid_src.innovation_variance[0])
&& fuseDirectStateMeasurement(State::vel.idx + 1, aid_src.observation_variance[1], aid_src.innovation[1],
aid_src.innovation_variance[1])
&& fuseDirectStateMeasurement(State::vel.idx + 2, aid_src.observation_variance[2], aid_src.innovation[2],
aid_src.innovation_variance[2])
) {
aid_src.fused = true;
aid_src.time_last_fuse = _time_delayed_us;
+1 -1
View File
@@ -98,7 +98,7 @@ bool Ekf::fuseYaw(estimator_aid_source1d_s &aid_src_status, const VectorState &H
_innov_check_fail_status.flags.reject_yaw = false;
}
if (measurementUpdate(Kfusion, H_YAW, aid_src_status.observation_variance, aid_src_status.innovation)) {
if (fuseMeasurement(Kfusion, H_YAW, aid_src_status.observation_variance, aid_src_status.innovation)) {
_time_last_heading_fuse = _time_delayed_us;