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AP_NavEKF3: Don't learn poorly observed IMU dvel bias states before flight

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This commit is contained in:
Paul Riseborough 2021-03-08 17:09:02 +11:00 committed by Andrew Tridgell
parent 4b1c334bba
commit a07427fd30
7 changed files with 138 additions and 38 deletions
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22
libraries/AP_NavEKF3/AP_NavEKF3_AirDataFusion.cpp
View File

@ -94,9 +94,14 @@ void NavEKF3_core::FuseAirspeed()
}
if (!inhibitDelVelBiasStates && !airDataFusionWindOnly) {
Kfusion[13] = SK_TAS[0]*(P[13][4]*SH_TAS[2] - P[13][22]*SH_TAS[2] + P[13][5]*SK_TAS[1] - P[13][23]*SK_TAS[1] + P[13][6]*vd*SH_TAS[0]);
Kfusion[14] = SK_TAS[0]*(P[14][4]*SH_TAS[2] - P[14][22]*SH_TAS[2] + P[14][5]*SK_TAS[1] - P[14][23]*SK_TAS[1] + P[14][6]*vd*SH_TAS[0]);
Kfusion[15] = SK_TAS[0]*(P[15][4]*SH_TAS[2] - P[15][22]*SH_TAS[2] + P[15][5]*SK_TAS[1] - P[15][23]*SK_TAS[1] + P[15][6]*vd*SH_TAS[0]);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = SK_TAS[0]*(P[stateIndex][4]*SH_TAS[2] - P[stateIndex][22]*SH_TAS[2] + P[stateIndex][5]*SK_TAS[1] - P[stateIndex][23]*SK_TAS[1] + P[stateIndex][6]*vd*SH_TAS[0]);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);
@ -388,9 +393,14 @@ void NavEKF3_core::FuseSideslip()
}
if (!inhibitDelVelBiasStates && !airDataFusionWindOnly) {
Kfusion[13] = SK_BETA[0]*(P[13][0]*SK_BETA[5] + P[13][1]*SK_BETA[4] - P[13][4]*SK_BETA[1] + P[13][5]*SK_BETA[2] + P[13][2]*SK_BETA[6] + P[13][6]*SK_BETA[3] - P[13][3]*SK_BETA[7] + P[13][22]*SK_BETA[1] - P[13][23]*SK_BETA[2]);
Kfusion[14] = SK_BETA[0]*(P[14][0]*SK_BETA[5] + P[14][1]*SK_BETA[4] - P[14][4]*SK_BETA[1] + P[14][5]*SK_BETA[2] + P[14][2]*SK_BETA[6] + P[14][6]*SK_BETA[3] - P[14][3]*SK_BETA[7] + P[14][22]*SK_BETA[1] - P[14][23]*SK_BETA[2]);
Kfusion[15] = SK_BETA[0]*(P[15][0]*SK_BETA[5] + P[15][1]*SK_BETA[4] - P[15][4]*SK_BETA[1] + P[15][5]*SK_BETA[2] + P[15][2]*SK_BETA[6] + P[15][6]*SK_BETA[3] - P[15][3]*SK_BETA[7] + P[15][22]*SK_BETA[1] - P[15][23]*SK_BETA[2]);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = SK_BETA[0]*(P[stateIndex][0]*SK_BETA[5] + P[stateIndex][1]*SK_BETA[4] - P[stateIndex][4]*SK_BETA[1] + P[stateIndex][5]*SK_BETA[2] + P[stateIndex][2]*SK_BETA[6] + P[stateIndex][6]*SK_BETA[3] - P[stateIndex][3]*SK_BETA[7] + P[stateIndex][22]*SK_BETA[1] - P[stateIndex][23]*SK_BETA[2]);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);

44
libraries/AP_NavEKF3/AP_NavEKF3_MagFusion.cpp
View File

@ -602,9 +602,14 @@ void NavEKF3_core::FuseMagnetometer()
}
if (!inhibitDelVelBiasStates) {
Kfusion[13] = SK_MX[0]*(P[13][19] + P[13][1]*SH_MAG[0] - P[13][2]*SH_MAG[1] + P[13][3]*SH_MAG[2] + P[13][0]*SK_MX[2] - P[13][16]*SK_MX[1] + P[13][17]*SK_MX[4] - P[13][18]*SK_MX[3]);
Kfusion[14] = SK_MX[0]*(P[14][19] + P[14][1]*SH_MAG[0] - P[14][2]*SH_MAG[1] + P[14][3]*SH_MAG[2] + P[14][0]*SK_MX[2] - P[14][16]*SK_MX[1] + P[14][17]*SK_MX[4] - P[14][18]*SK_MX[3]);
Kfusion[15] = SK_MX[0]*(P[15][19] + P[15][1]*SH_MAG[0] - P[15][2]*SH_MAG[1] + P[15][3]*SH_MAG[2] + P[15][0]*SK_MX[2] - P[15][16]*SK_MX[1] + P[15][17]*SK_MX[4] - P[15][18]*SK_MX[3]);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = SK_MX[0]*(P[stateIndex][19] + P[stateIndex][1]*SH_MAG[0] - P[stateIndex][2]*SH_MAG[1] + P[stateIndex][3]*SH_MAG[2] + P[stateIndex][0]*SK_MX[2] - P[stateIndex][16]*SK_MX[1] + P[stateIndex][17]*SK_MX[4] - P[stateIndex][18]*SK_MX[3]);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);
@ -677,9 +682,14 @@ void NavEKF3_core::FuseMagnetometer()
}
if (!inhibitDelVelBiasStates) {
Kfusion[13] = SK_MY[0]*(P[13][20] + P[13][0]*SH_MAG[2] + P[13][1]*SH_MAG[1] + P[13][2]*SH_MAG[0] - P[13][3]*SK_MY[2] - P[13][17]*SK_MY[1] - P[13][16]*SK_MY[3] + P[13][18]*SK_MY[4]);
Kfusion[14] = SK_MY[0]*(P[14][20] + P[14][0]*SH_MAG[2] + P[14][1]*SH_MAG[1] + P[14][2]*SH_MAG[0] - P[14][3]*SK_MY[2] - P[14][17]*SK_MY[1] - P[14][16]*SK_MY[3] + P[14][18]*SK_MY[4]);
Kfusion[15] = SK_MY[0]*(P[15][20] + P[15][0]*SH_MAG[2] + P[15][1]*SH_MAG[1] + P[15][2]*SH_MAG[0] - P[15][3]*SK_MY[2] - P[15][17]*SK_MY[1] - P[15][16]*SK_MY[3] + P[15][18]*SK_MY[4]);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = SK_MY[0]*(P[stateIndex][20] + P[stateIndex][0]*SH_MAG[2] + P[stateIndex][1]*SH_MAG[1] + P[stateIndex][2]*SH_MAG[0] - P[stateIndex][3]*SK_MY[2] - P[stateIndex][17]*SK_MY[1] - P[stateIndex][16]*SK_MY[3] + P[stateIndex][18]*SK_MY[4]);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);
@ -754,9 +764,14 @@ void NavEKF3_core::FuseMagnetometer()
}
if (!inhibitDelVelBiasStates) {
Kfusion[13] = SK_MZ[0]*(P[13][21] + P[13][0]*SH_MAG[1] - P[13][1]*SH_MAG[2] + P[13][3]*SH_MAG[0] + P[13][2]*SK_MZ[2] + P[13][18]*SK_MZ[1] + P[13][16]*SK_MZ[4] - P[13][17]*SK_MZ[3]);
Kfusion[14] = SK_MZ[0]*(P[14][21] + P[14][0]*SH_MAG[1] - P[14][1]*SH_MAG[2] + P[14][3]*SH_MAG[0] + P[14][2]*SK_MZ[2] + P[14][18]*SK_MZ[1] + P[14][16]*SK_MZ[4] - P[14][17]*SK_MZ[3]);
Kfusion[15] = SK_MZ[0]*(P[15][21] + P[15][0]*SH_MAG[1] - P[15][1]*SH_MAG[2] + P[15][3]*SH_MAG[0] + P[15][2]*SK_MZ[2] + P[15][18]*SK_MZ[1] + P[15][16]*SK_MZ[4] - P[15][17]*SK_MZ[3]);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = SK_MZ[0]*(P[stateIndex][21] + P[stateIndex][0]*SH_MAG[1] - P[stateIndex][1]*SH_MAG[2] + P[stateIndex][3]*SH_MAG[0] + P[stateIndex][2]*SK_MZ[2] + P[stateIndex][18]*SK_MZ[1] + P[stateIndex][16]*SK_MZ[4] - P[stateIndex][17]*SK_MZ[3]);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);
@ -1287,9 +1302,14 @@ void NavEKF3_core::FuseDeclination(float declErr)
}
if (!inhibitDelVelBiasStates) {
Kfusion[13] = -t4*t13*(P[13][16]*magE-P[13][17]*magN);
Kfusion[14] = -t4*t13*(P[14][16]*magE-P[14][17]*magN);
Kfusion[15] = -t4*t13*(P[15][16]*magE-P[15][17]*magN);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = -t4*t13*(P[stateIndex][16]*magE-P[stateIndex][17]*magN);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);

22
libraries/AP_NavEKF3/AP_NavEKF3_OptFlowFusion.cpp
View File

@ -466,9 +466,14 @@ void NavEKF3_core::FuseOptFlow()
}
if (!inhibitDelVelBiasStates) {
Kfusion[13] = t78*(P[13][0]*t2*t5-P[13][4]*t2*t7+P[13][1]*t2*t15+P[13][6]*t2*t10+P[13][2]*t2*t19-P[13][3]*t2*t22+P[13][5]*t2*t27);
Kfusion[14] = t78*(P[14][0]*t2*t5-P[14][4]*t2*t7+P[14][1]*t2*t15+P[14][6]*t2*t10+P[14][2]*t2*t19-P[14][3]*t2*t22+P[14][5]*t2*t27);
Kfusion[15] = t78*(P[15][0]*t2*t5-P[15][4]*t2*t7+P[15][1]*t2*t15+P[15][6]*t2*t10+P[15][2]*t2*t19-P[15][3]*t2*t22+P[15][5]*t2*t27);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = t78*(P[stateIndex][0]*t2*t5-P[stateIndex][4]*t2*t7+P[stateIndex][1]*t2*t15+P[stateIndex][6]*t2*t10+P[stateIndex][2]*t2*t19-P[stateIndex][3]*t2*t22+P[stateIndex][5]*t2*t27);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);
@ -637,9 +642,14 @@ void NavEKF3_core::FuseOptFlow()
}
if (!inhibitDelVelBiasStates) {
Kfusion[13] = -t78*(P[13][0]*t2*t5+P[13][5]*t2*t8-P[13][6]*t2*t10+P[13][1]*t2*t16-P[13][2]*t2*t19+P[13][3]*t2*t22+P[13][4]*t2*t27);
Kfusion[14] = -t78*(P[14][0]*t2*t5+P[14][5]*t2*t8-P[14][6]*t2*t10+P[14][1]*t2*t16-P[14][2]*t2*t19+P[14][3]*t2*t22+P[14][4]*t2*t27);
Kfusion[15] = -t78*(P[15][0]*t2*t5+P[15][5]*t2*t8-P[15][6]*t2*t10+P[15][1]*t2*t16-P[15][2]*t2*t19+P[15][3]*t2*t22+P[15][4]*t2*t27);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = -t78*(P[stateIndex][0]*t2*t5+P[stateIndex][5]*t2*t8-P[stateIndex][6]*t2*t10+P[stateIndex][1]*t2*t16-P[stateIndex][2]*t2*t19+P[stateIndex][3]*t2*t22+P[stateIndex][4]*t2*t27);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);

33
libraries/AP_NavEKF3/AP_NavEKF3_PosVelFusion.cpp
View File

@ -1363,9 +1363,14 @@ void NavEKF3_core::FuseBodyVel()
}
if (!inhibitDelVelBiasStates) {
Kfusion[13] = t77*(P[13][5]*t4+P[13][4]*t9+P[13][0]*t14-P[13][6]*t11+P[13][1]*t18-P[13][2]*t21+P[13][3]*t24);
Kfusion[14] = t77*(P[14][5]*t4+P[14][4]*t9+P[14][0]*t14-P[14][6]*t11+P[14][1]*t18-P[14][2]*t21+P[14][3]*t24);
Kfusion[15] = t77*(P[15][5]*t4+P[15][4]*t9+P[15][0]*t14-P[15][6]*t11+P[15][1]*t18-P[15][2]*t21+P[15][3]*t24);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = t77*(P[stateIndex][5]*t4+P[stateIndex][4]*t9+P[stateIndex][0]*t14-P[stateIndex][6]*t11+P[stateIndex][1]*t18-P[stateIndex][2]*t21+P[stateIndex][3]*t24);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);
@ -1535,9 +1540,14 @@ void NavEKF3_core::FuseBodyVel()
}
if (!inhibitDelVelBiasStates) {
Kfusion[13] = t77*(-P[13][4]*t3+P[13][5]*t8+P[13][0]*t15+P[13][6]*t12+P[13][1]*t18+P[13][2]*t22-P[13][3]*t25);
Kfusion[14] = t77*(-P[14][4]*t3+P[14][5]*t8+P[14][0]*t15+P[14][6]*t12+P[14][1]*t18+P[14][2]*t22-P[14][3]*t25);
Kfusion[15] = t77*(-P[15][4]*t3+P[15][5]*t8+P[15][0]*t15+P[15][6]*t12+P[15][1]*t18+P[15][2]*t22-P[15][3]*t25);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = t77*(-P[stateIndex][4]*t3+P[stateIndex][5]*t8+P[stateIndex][0]*t15+P[stateIndex][6]*t12+P[stateIndex][1]*t18+P[stateIndex][2]*t22-P[stateIndex][3]*t25);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);
@ -1708,9 +1718,14 @@ void NavEKF3_core::FuseBodyVel()
}
if (!inhibitDelVelBiasStates) {
Kfusion[13] = t77*(P[13][4]*t4+P[13][0]*t14+P[13][6]*t9-P[13][5]*t11-P[13][1]*t17+P[13][2]*t20+P[13][3]*t24);
Kfusion[14] = t77*(P[14][4]*t4+P[14][0]*t14+P[14][6]*t9-P[14][5]*t11-P[14][1]*t17+P[14][2]*t20+P[14][3]*t24);
Kfusion[15] = t77*(P[15][4]*t4+P[15][0]*t14+P[15][6]*t9-P[15][5]*t11-P[15][1]*t17+P[15][2]*t20+P[15][3]*t24);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = t77*(P[stateIndex][4]*t4+P[stateIndex][0]*t14+P[stateIndex][6]*t9-P[stateIndex][5]*t11-P[stateIndex][1]*t17+P[stateIndex][2]*t20+P[stateIndex][3]*t24);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);

11
libraries/AP_NavEKF3/AP_NavEKF3_RngBcnFusion.cpp
View File

@ -149,9 +149,14 @@ void NavEKF3_core::FuseRngBcn()
}
if (!inhibitDelVelBiasStates) {
Kfusion[13] = -t26*(P[13][7]*t4*t9+P[13][8]*t3*t9+P[13][9]*t2*t9);
Kfusion[14] = -t26*(P[14][7]*t4*t9+P[14][8]*t3*t9+P[14][9]*t2*t9);
Kfusion[15] = -t26*(P[15][7]*t4*t9+P[15][8]*t3*t9+P[15][9]*t2*t9);
for (uint8_t index = 0; index < 3; index++) {
uint8_t stateIndex = index + 13;
if (!dvelBiasAxisInhibit[index]) {
Kfusion[stateIndex] = -t26*(P[stateIndex][7]*t4*t9+P[stateIndex][8]*t3*t9+P[stateIndex][9]*t2*t9);
} else {
Kfusion[stateIndex] = 0.0f;
}
}
} else {
// zero indexes 13 to 15 = 3*4 bytes
memset(&Kfusion[13], 0, 12);

38
libraries/AP_NavEKF3/AP_NavEKF3_core.cpp
View File

@ -226,6 +226,8 @@ void NavEKF3_core::InitialiseVariables()
lastRngMeasTime_ms = 0;
// initialise other variables
memset(&dvelBiasAxisInhibit, 0, sizeof(dvelBiasAxisInhibit));
dvelBiasAxisVarPrev.zero();
gpsNoiseScaler = 1.0f;
hgtTimeout = true;
tasTimeout = true;
@ -1131,6 +1133,24 @@ void NavEKF3_core::CovariancePrediction(Vector3f *rotVarVecPtr)
float _accNoise = constrain_float(frontend->_accNoise, 0.0f, 10.0f);
dvxVar = dvyVar = dvzVar = sq(dt*_accNoise);
if (!inhibitDelVelBiasStates) {
for (unsigned stateIndex = 13; stateIndex <= 15; stateIndex++) {
const unsigned index = stateIndex - 13;
// Don't attempt learning of IMU delta velocty bias if on ground and not aligned with the gravity vector
const bool is_bias_observable = (fabsf(prevTnb[index][2]) > 0.8f) && onGround;
if (!is_bias_observable && !dvelBiasAxisInhibit[index]) {
// store variances to be reinstated wben learnign can commence later
dvelBiasAxisVarPrev[index] = P[stateIndex][stateIndex];
dvelBiasAxisInhibit[index] = true;
} else if (is_bias_observable && dvelBiasAxisInhibit[index]) {
P[stateIndex][stateIndex] = dvelBiasAxisVarPrev[index];
dvelBiasAxisInhibit[index] = false;
}
}
}
// calculate the predicted covariance due to inertial sensor error propagation
// we calculate the lower diagonal and copy to take advantage of symmetry
@ -1659,6 +1679,18 @@ void NavEKF3_core::CovariancePrediction(Vector3f *rotVarVecPtr)
}
}
// inactive delta velocity bias states have all covariances zeroed to prevent
// interacton with other states
if (!inhibitDelVelBiasStates) {
for (uint8_t index=0; index<3; index++) {
uint8_t stateIndex = index + 13;
if (dvelBiasAxisInhibit[index]) {
zeroCols(nextP,stateIndex,stateIndex);
nextP[stateIndex][stateIndex] = dvelBiasAxisVarPrev[index];
}
}
}
// if the total position variance exceeds 1e4 (100m), then stop covariance
// growth by setting the predicted to the previous values
// This prevent an ill conditioned matrix from occurring for long periods
@ -1783,6 +1815,7 @@ void NavEKF3_core::ConstrainVariances()
zeroRows(P,10,12);
}
const float minStateVarTarget = 1E-8f;
if (!inhibitDelVelBiasStates) {
// Find the maximum delta velocity bias state variance and request a covariance reset if any variance is below the safe minimum
@ -1799,7 +1832,6 @@ void NavEKF3_core::ConstrainVariances()
// To ensure stability of the covariance matrix operations, the ratio of a max and min variance must
// not exceed 100 and the minimum variance must not fall below the target minimum
const float minStateVarTarget = 1E-8f;
float minAllowedStateVar = fmaxf(0.01f * maxStateVar, minStateVarTarget);
for (uint8_t stateIndex=13; stateIndex<=15; stateIndex++) {
P[stateIndex][stateIndex] = constrain_float(P[stateIndex][stateIndex], minAllowedStateVar, sq(10.0f * dtEkfAvg));
@ -1823,6 +1855,10 @@ void NavEKF3_core::ConstrainVariances()
} else {
zeroCols(P,13,15);
zeroRows(P,13,15);
for (uint8_t i=0; i<=2; i++) {
const uint8_t stateIndex = 1 + 13;
P[stateIndex][stateIndex] = fmaxf(P[stateIndex][stateIndex], minStateVarTarget);
}
}
if (!inhibitMagStates) {

6
libraries/AP_NavEKF3/AP_NavEKF3_core.h
View File

@ -1029,7 +1029,6 @@ private:
bool lastInhibitMagStates; // previous inhibitMagStates
bool needMagBodyVarReset; // we need to reset mag body variances at next CovariancePrediction
bool needEarthBodyVarReset; // we need to reset mag earth variances at next CovariancePrediction
bool inhibitDelVelBiasStates; // true when IMU delta velocity bias states are inactive
bool inhibitDelAngBiasStates; // true when IMU delta angle bias states are inactive
bool gpsNotAvailable; // bool true when valid GPS data is not available
struct Location EKF_origin; // LLH origin of the NED axis system
@ -1325,6 +1324,11 @@ private:
bool onGroundNotMoving; // true when on the ground and not moving
uint32_t lastMoveCheckLogTime_ms; // last time the movement check data was logged (msec)
// variables used to inhibit accel bias learning
bool inhibitDelVelBiasStates; // true when all IMU delta velocity bias states are de-activated
bool dvelBiasAxisInhibit[3] {}; // true when IMU delta velocity bias states for a specific axis is de-activated
Vector3f dvelBiasAxisVarPrev; // saved delta velocity XYZ bias variances (m/sec)**2
#if EK3_FEATURE_EXTERNAL_NAV
// external navigation fusion
EKF_obs_buffer_t<ext_nav_elements> storedExtNav; // external navigation data buffer