Merge pull request #49 from PX4/pr-fixMagCovariance

EKF: Fix magnetometer fusion and covariance handling
This commit is contained in:
Paul Riseborough
2016-02-18 10:22:36 +11:00
9 changed files with 515 additions and 394 deletions
+2 -1
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@@ -141,7 +141,7 @@ struct parameters {
float mag_declination_deg = 0.0f; // magnetic declination in degrees
float heading_innov_gate = 3.0f; // heading fusion innovation consistency gate size in standard deviations
float mag_innov_gate = 3.0f; // magnetometer fusion innovation consistency gate size in standard deviations
int mag_declination_source = 7; // bitmask used to control the handling of declination data
int mag_declination_source = 3; // bitmask used to control the handling of declination data
int mag_fusion_type = 0; // integer used to specify the type of magnetometer fusion used
// these parameters control the strictness of GPS quality checks used to determine uf the GPS is
@@ -220,6 +220,7 @@ union filter_control_status_u {
uint8_t mag_dec : 1; // 6 - true if synthetic magnetic declination measurements are being fused
uint8_t in_air : 1; // 7 - true when the vehicle is airborne
uint8_t armed : 1; // 8 - true when the vehicle motors are armed
uint8_t wind : 1; // 9 - true when wind velocity is being estimated
} flags;
uint16_t value;
};
+8
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@@ -145,6 +145,14 @@ void Ekf::controlFusionModes()
_control_status.flags.mag_dec = false;
}
// Placeholder for control of wind velocity states estimation
// TODO add methods for true airspeed and/or sidelsip fusion or some type of drag force measurement
if (false) {
_control_status.flags.wind = false;
}
// Store the status to enable change detection
_control_status_prev.value = _control_status.value;
}
void Ekf::calculateVehicleStatus()
+237 -184
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@@ -81,19 +81,22 @@ void Ekf::initialiseCovariance()
// accel z bias
P[15][15] = 0.0001f;
// variances for optional states
// these state variances are set to zero until the states are required, then they must be initialised
// earth magnetic field
P[16][16] = 0.0001f;
P[17][17] = 0.0001f;
P[18][18] = 0.0001f;
P[16][16] = 0.0f;
P[17][17] = 0.0f;
P[18][18] = 0.0f;
// body magnetic field
P[19][19] = 0.0001f;
P[20][20] = 0.0001f;
P[21][21] = 0.0001f;
P[19][19] = 0.0f;
P[20][20] = 0.0f;
P[21][21] = 0.0f;
// wind
P[22][22] = 0.01f;
P[23][23] = 0.01f;
P[22][22] = 0.0f;
P[23][23] = 0.0f;
}
@@ -131,9 +134,33 @@ void Ekf::predictCovariance()
float d_ang_bias_sig = dt * math::constrain(_params.gyro_bias_p_noise, 0.0f, 1e-4f);
float d_vel_bias_sig = dt * math::constrain(_params.accel_bias_p_noise, 0.0f, 1e-2f);
float d_ang_scale_sig = dt * math::constrain(_params.gyro_scale_p_noise, 0.0f, 1e-2f);
float mag_I_sig = dt * math::constrain(_params.mag_p_noise, 0.0f, 1e-1f);
float mag_B_sig = dt * math::constrain(_params.mag_p_noise, 0.0f, 1e-1f);
float wind_vel_sig = dt * math::constrain(_params.wind_vel_p_noise, 0.0f, 1.0f);
float mag_I_sig, mag_B_sig;
// Don't continue to grow the body field variances if they are becoming too large or we are not doing 3-axis fusion as this can make the covariance matrix badly conditioned
if (_control_status.flags.mag_3D && (P[16][16] + P[17][17] + P[18][8]) < 0.1f) {
mag_I_sig = dt * math::constrain(_params.mag_p_noise, 0.0f, 1e-1f);
} else {
mag_I_sig = 0.0f;
}
// Don't continue to grow the earth field variances if they is becoming too large or we are not doing 3-axis fusion as this can make the covariance matrix badly conditioned
if (_control_status.flags.mag_3D && (P[19][19] + P[20][20] + P[21][21]) < 0.1f) {
mag_B_sig = dt * math::constrain(_params.mag_p_noise, 0.0f, 1e-1f);
} else {
mag_B_sig = 0.0f;
}
float wind_vel_sig;
// Don't continue to grow wind velocity state variances if they are becoming too large or we are not using wind velocity states as this can make the covariance matrix badly conditioned
if (_control_status.flags.wind && (P[22][22] + P[22][22]) < 1000.0f) {
wind_vel_sig = dt * math::constrain(_params.wind_vel_p_noise, 0.0f, 1.0f);
} else {
wind_vel_sig = 0.0f;
}
for (unsigned i = 0; i < 9; i++) {
process_noise[i] = 0.0f;
@@ -493,170 +520,200 @@ void Ekf::predictCovariance()
nextP[13][15] = P[13][15];
nextP[14][15] = P[14][15];
nextP[15][15] = P[15][15];
nextP[0][16] = P[0][16] * SPP[5] - P[1][16] * SPP[4] + P[2][16] * SPP[7] + P[9][16] * SPP[22] + P[12][16] * SPP[18];
nextP[1][16] = P[1][16] * SPP[6] - P[0][16] * SPP[2] - P[2][16] * SPP[8] + P[10][16] * SPP[22] + P[13][16] * SPP[17];
nextP[2][16] = P[0][16] * SPP[14] - P[1][16] * SPP[3] + P[2][16] * SPP[13] + P[11][16] * SPP[22] + P[14][16] * SPP[16];
nextP[3][16] = P[3][16] + P[0][16] * SPP[1] + P[1][16] * SPP[19] + P[2][16] * SPP[15] - P[15][16] * SPP[21];
nextP[4][16] = P[4][16] + P[15][16] * SF[22] + P[0][16] * SPP[20] + P[1][16] * SPP[12] + P[2][16] * SPP[11];
nextP[5][16] = P[5][16] + P[15][16] * SF[20] - P[0][16] * SPP[9] + P[1][16] * SPP[10] + P[2][16] * SPP[0];
nextP[6][16] = P[6][16] + P[3][16] * dt;
nextP[7][16] = P[7][16] + P[4][16] * dt;
nextP[8][16] = P[8][16] + P[5][16] * dt;
nextP[9][16] = P[9][16];
nextP[10][16] = P[10][16];
nextP[11][16] = P[11][16];
nextP[12][16] = P[12][16];
nextP[13][16] = P[13][16];
nextP[14][16] = P[14][16];
nextP[15][16] = P[15][16];
nextP[16][16] = P[16][16];
nextP[0][17] = P[0][17] * SPP[5] - P[1][17] * SPP[4] + P[2][17] * SPP[7] + P[9][17] * SPP[22] + P[12][17] * SPP[18];
nextP[1][17] = P[1][17] * SPP[6] - P[0][17] * SPP[2] - P[2][17] * SPP[8] + P[10][17] * SPP[22] + P[13][17] * SPP[17];
nextP[2][17] = P[0][17] * SPP[14] - P[1][17] * SPP[3] + P[2][17] * SPP[13] + P[11][17] * SPP[22] + P[14][17] * SPP[16];
nextP[3][17] = P[3][17] + P[0][17] * SPP[1] + P[1][17] * SPP[19] + P[2][17] * SPP[15] - P[15][17] * SPP[21];
nextP[4][17] = P[4][17] + P[15][17] * SF[22] + P[0][17] * SPP[20] + P[1][17] * SPP[12] + P[2][17] * SPP[11];
nextP[5][17] = P[5][17] + P[15][17] * SF[20] - P[0][17] * SPP[9] + P[1][17] * SPP[10] + P[2][17] * SPP[0];
nextP[6][17] = P[6][17] + P[3][17] * dt;
nextP[7][17] = P[7][17] + P[4][17] * dt;
nextP[8][17] = P[8][17] + P[5][17] * dt;
nextP[9][17] = P[9][17];
nextP[10][17] = P[10][17];
nextP[11][17] = P[11][17];
nextP[12][17] = P[12][17];
nextP[13][17] = P[13][17];
nextP[14][17] = P[14][17];
nextP[15][17] = P[15][17];
nextP[16][17] = P[16][17];
nextP[17][17] = P[17][17];
nextP[0][18] = P[0][18] * SPP[5] - P[1][18] * SPP[4] + P[2][18] * SPP[7] + P[9][18] * SPP[22] + P[12][18] * SPP[18];
nextP[1][18] = P[1][18] * SPP[6] - P[0][18] * SPP[2] - P[2][18] * SPP[8] + P[10][18] * SPP[22] + P[13][18] * SPP[17];
nextP[2][18] = P[0][18] * SPP[14] - P[1][18] * SPP[3] + P[2][18] * SPP[13] + P[11][18] * SPP[22] + P[14][18] * SPP[16];
nextP[3][18] = P[3][18] + P[0][18] * SPP[1] + P[1][18] * SPP[19] + P[2][18] * SPP[15] - P[15][18] * SPP[21];
nextP[4][18] = P[4][18] + P[15][18] * SF[22] + P[0][18] * SPP[20] + P[1][18] * SPP[12] + P[2][18] * SPP[11];
nextP[5][18] = P[5][18] + P[15][18] * SF[20] - P[0][18] * SPP[9] + P[1][18] * SPP[10] + P[2][18] * SPP[0];
nextP[6][18] = P[6][18] + P[3][18] * dt;
nextP[7][18] = P[7][18] + P[4][18] * dt;
nextP[8][18] = P[8][18] + P[5][18] * dt;
nextP[9][18] = P[9][18];
nextP[10][18] = P[10][18];
nextP[11][18] = P[11][18];
nextP[12][18] = P[12][18];
nextP[13][18] = P[13][18];
nextP[14][18] = P[14][18];
nextP[15][18] = P[15][18];
nextP[16][18] = P[16][18];
nextP[17][18] = P[17][18];
nextP[18][18] = P[18][18];
nextP[0][19] = P[0][19] * SPP[5] - P[1][19] * SPP[4] + P[2][19] * SPP[7] + P[9][19] * SPP[22] + P[12][19] * SPP[18];
nextP[1][19] = P[1][19] * SPP[6] - P[0][19] * SPP[2] - P[2][19] * SPP[8] + P[10][19] * SPP[22] + P[13][19] * SPP[17];
nextP[2][19] = P[0][19] * SPP[14] - P[1][19] * SPP[3] + P[2][19] * SPP[13] + P[11][19] * SPP[22] + P[14][19] * SPP[16];
nextP[3][19] = P[3][19] + P[0][19] * SPP[1] + P[1][19] * SPP[19] + P[2][19] * SPP[15] - P[15][19] * SPP[21];
nextP[4][19] = P[4][19] + P[15][19] * SF[22] + P[0][19] * SPP[20] + P[1][19] * SPP[12] + P[2][19] * SPP[11];
nextP[5][19] = P[5][19] + P[15][19] * SF[20] - P[0][19] * SPP[9] + P[1][19] * SPP[10] + P[2][19] * SPP[0];
nextP[6][19] = P[6][19] + P[3][19] * dt;
nextP[7][19] = P[7][19] + P[4][19] * dt;
nextP[8][19] = P[8][19] + P[5][19] * dt;
nextP[9][19] = P[9][19];
nextP[10][19] = P[10][19];
nextP[11][19] = P[11][19];
nextP[12][19] = P[12][19];
nextP[13][19] = P[13][19];
nextP[14][19] = P[14][19];
nextP[15][19] = P[15][19];
nextP[16][19] = P[16][19];
nextP[17][19] = P[17][19];
nextP[18][19] = P[18][19];
nextP[19][19] = P[19][19];
nextP[0][20] = P[0][20] * SPP[5] - P[1][20] * SPP[4] + P[2][20] * SPP[7] + P[9][20] * SPP[22] + P[12][20] * SPP[18];
nextP[1][20] = P[1][20] * SPP[6] - P[0][20] * SPP[2] - P[2][20] * SPP[8] + P[10][20] * SPP[22] + P[13][20] * SPP[17];
nextP[2][20] = P[0][20] * SPP[14] - P[1][20] * SPP[3] + P[2][20] * SPP[13] + P[11][20] * SPP[22] + P[14][20] * SPP[16];
nextP[3][20] = P[3][20] + P[0][20] * SPP[1] + P[1][20] * SPP[19] + P[2][20] * SPP[15] - P[15][20] * SPP[21];
nextP[4][20] = P[4][20] + P[15][20] * SF[22] + P[0][20] * SPP[20] + P[1][20] * SPP[12] + P[2][20] * SPP[11];
nextP[5][20] = P[5][20] + P[15][20] * SF[20] - P[0][20] * SPP[9] + P[1][20] * SPP[10] + P[2][20] * SPP[0];
nextP[6][20] = P[6][20] + P[3][20] * dt;
nextP[7][20] = P[7][20] + P[4][20] * dt;
nextP[8][20] = P[8][20] + P[5][20] * dt;
nextP[9][20] = P[9][20];
nextP[10][20] = P[10][20];
nextP[11][20] = P[11][20];
nextP[12][20] = P[12][20];
nextP[13][20] = P[13][20];
nextP[14][20] = P[14][20];
nextP[15][20] = P[15][20];
nextP[16][20] = P[16][20];
nextP[17][20] = P[17][20];
nextP[18][20] = P[18][20];
nextP[19][20] = P[19][20];
nextP[20][20] = P[20][20];
nextP[0][21] = P[0][21] * SPP[5] - P[1][21] * SPP[4] + P[2][21] * SPP[7] + P[9][21] * SPP[22] + P[12][21] * SPP[18];
nextP[1][21] = P[1][21] * SPP[6] - P[0][21] * SPP[2] - P[2][21] * SPP[8] + P[10][21] * SPP[22] + P[13][21] * SPP[17];
nextP[2][21] = P[0][21] * SPP[14] - P[1][21] * SPP[3] + P[2][21] * SPP[13] + P[11][21] * SPP[22] + P[14][21] * SPP[16];
nextP[3][21] = P[3][21] + P[0][21] * SPP[1] + P[1][21] * SPP[19] + P[2][21] * SPP[15] - P[15][21] * SPP[21];
nextP[4][21] = P[4][21] + P[15][21] * SF[22] + P[0][21] * SPP[20] + P[1][21] * SPP[12] + P[2][21] * SPP[11];
nextP[5][21] = P[5][21] + P[15][21] * SF[20] - P[0][21] * SPP[9] + P[1][21] * SPP[10] + P[2][21] * SPP[0];
nextP[6][21] = P[6][21] + P[3][21] * dt;
nextP[7][21] = P[7][21] + P[4][21] * dt;
nextP[8][21] = P[8][21] + P[5][21] * dt;
nextP[9][21] = P[9][21];
nextP[10][21] = P[10][21];
nextP[11][21] = P[11][21];
nextP[12][21] = P[12][21];
nextP[13][21] = P[13][21];
nextP[14][21] = P[14][21];
nextP[15][21] = P[15][21];
nextP[16][21] = P[16][21];
nextP[17][21] = P[17][21];
nextP[18][21] = P[18][21];
nextP[19][21] = P[19][21];
nextP[20][21] = P[20][21];
nextP[21][21] = P[21][21];
nextP[0][22] = P[0][22] * SPP[5] - P[1][22] * SPP[4] + P[2][22] * SPP[7] + P[9][22] * SPP[22] + P[12][22] * SPP[18];
nextP[1][22] = P[1][22] * SPP[6] - P[0][22] * SPP[2] - P[2][22] * SPP[8] + P[10][22] * SPP[22] + P[13][22] * SPP[17];
nextP[2][22] = P[0][22] * SPP[14] - P[1][22] * SPP[3] + P[2][22] * SPP[13] + P[11][22] * SPP[22] + P[14][22] * SPP[16];
nextP[3][22] = P[3][22] + P[0][22] * SPP[1] + P[1][22] * SPP[19] + P[2][22] * SPP[15] - P[15][22] * SPP[21];
nextP[4][22] = P[4][22] + P[15][22] * SF[22] + P[0][22] * SPP[20] + P[1][22] * SPP[12] + P[2][22] * SPP[11];
nextP[5][22] = P[5][22] + P[15][22] * SF[20] - P[0][22] * SPP[9] + P[1][22] * SPP[10] + P[2][22] * SPP[0];
nextP[6][22] = P[6][22] + P[3][22] * dt;
nextP[7][22] = P[7][22] + P[4][22] * dt;
nextP[8][22] = P[8][22] + P[5][22] * dt;
nextP[9][22] = P[9][22];
nextP[10][22] = P[10][22];
nextP[11][22] = P[11][22];
nextP[12][22] = P[12][22];
nextP[13][22] = P[13][22];
nextP[14][22] = P[14][22];
nextP[15][22] = P[15][22];
nextP[16][22] = P[16][22];
nextP[17][22] = P[17][22];
nextP[18][22] = P[18][22];
nextP[19][22] = P[19][22];
nextP[20][22] = P[20][22];
nextP[21][22] = P[21][22];
nextP[22][22] = P[22][22];
nextP[0][23] = P[0][23] * SPP[5] - P[1][23] * SPP[4] + P[2][23] * SPP[7] + P[9][23] * SPP[22] + P[12][23] * SPP[18];
nextP[1][23] = P[1][23] * SPP[6] - P[0][23] * SPP[2] - P[2][23] * SPP[8] + P[10][23] * SPP[22] + P[13][23] * SPP[17];
nextP[2][23] = P[0][23] * SPP[14] - P[1][23] * SPP[3] + P[2][23] * SPP[13] + P[11][23] * SPP[22] + P[14][23] * SPP[16];
nextP[3][23] = P[3][23] + P[0][23] * SPP[1] + P[1][23] * SPP[19] + P[2][23] * SPP[15] - P[15][23] * SPP[21];
nextP[4][23] = P[4][23] + P[15][23] * SF[22] + P[0][23] * SPP[20] + P[1][23] * SPP[12] + P[2][23] * SPP[11];
nextP[5][23] = P[5][23] + P[15][23] * SF[20] - P[0][23] * SPP[9] + P[1][23] * SPP[10] + P[2][23] * SPP[0];
nextP[6][23] = P[6][23] + P[3][23] * dt;
nextP[7][23] = P[7][23] + P[4][23] * dt;
nextP[8][23] = P[8][23] + P[5][23] * dt;
nextP[9][23] = P[9][23];
nextP[10][23] = P[10][23];
nextP[11][23] = P[11][23];
nextP[12][23] = P[12][23];
nextP[13][23] = P[13][23];
nextP[14][23] = P[14][23];
nextP[15][23] = P[15][23];
nextP[16][23] = P[16][23];
nextP[17][23] = P[17][23];
nextP[18][23] = P[18][23];
nextP[19][23] = P[19][23];
nextP[20][23] = P[20][23];
nextP[21][23] = P[21][23];
nextP[22][23] = P[22][23];
nextP[23][23] = P[23][23];
// Don't do covariance prediction on magnetic field states unless we are using 3-axis fusion
if (_control_status.flags.mag_3D) {
// Check if we have just transitioned into 3-axis fusion and set the state variances
if (!_control_status_prev.flags.mag_3D) {
for (uint8_t index = 16; index <= 21; index++) {
P[index][index] = sq(fmaxf(_params.mag_noise, 0.001f));
}
}
nextP[0][16] = P[0][16] * SPP[5] - P[1][16] * SPP[4] + P[2][16] * SPP[7] + P[9][16] * SPP[22] + P[12][16] * SPP[18];
nextP[1][16] = P[1][16] * SPP[6] - P[0][16] * SPP[2] - P[2][16] * SPP[8] + P[10][16] * SPP[22] + P[13][16] * SPP[17];
nextP[2][16] = P[0][16] * SPP[14] - P[1][16] * SPP[3] + P[2][16] * SPP[13] + P[11][16] * SPP[22] + P[14][16] * SPP[16];
nextP[3][16] = P[3][16] + P[0][16] * SPP[1] + P[1][16] * SPP[19] + P[2][16] * SPP[15] - P[15][16] * SPP[21];
nextP[4][16] = P[4][16] + P[15][16] * SF[22] + P[0][16] * SPP[20] + P[1][16] * SPP[12] + P[2][16] * SPP[11];
nextP[5][16] = P[5][16] + P[15][16] * SF[20] - P[0][16] * SPP[9] + P[1][16] * SPP[10] + P[2][16] * SPP[0];
nextP[6][16] = P[6][16] + P[3][16] * dt;
nextP[7][16] = P[7][16] + P[4][16] * dt;
nextP[8][16] = P[8][16] + P[5][16] * dt;
nextP[9][16] = P[9][16];
nextP[10][16] = P[10][16];
nextP[11][16] = P[11][16];
nextP[12][16] = P[12][16];
nextP[13][16] = P[13][16];
nextP[14][16] = P[14][16];
nextP[15][16] = P[15][16];
nextP[16][16] = P[16][16];
nextP[0][17] = P[0][17] * SPP[5] - P[1][17] * SPP[4] + P[2][17] * SPP[7] + P[9][17] * SPP[22] + P[12][17] * SPP[18];
nextP[1][17] = P[1][17] * SPP[6] - P[0][17] * SPP[2] - P[2][17] * SPP[8] + P[10][17] * SPP[22] + P[13][17] * SPP[17];
nextP[2][17] = P[0][17] * SPP[14] - P[1][17] * SPP[3] + P[2][17] * SPP[13] + P[11][17] * SPP[22] + P[14][17] * SPP[16];
nextP[3][17] = P[3][17] + P[0][17] * SPP[1] + P[1][17] * SPP[19] + P[2][17] * SPP[15] - P[15][17] * SPP[21];
nextP[4][17] = P[4][17] + P[15][17] * SF[22] + P[0][17] * SPP[20] + P[1][17] * SPP[12] + P[2][17] * SPP[11];
nextP[5][17] = P[5][17] + P[15][17] * SF[20] - P[0][17] * SPP[9] + P[1][17] * SPP[10] + P[2][17] * SPP[0];
nextP[6][17] = P[6][17] + P[3][17] * dt;
nextP[7][17] = P[7][17] + P[4][17] * dt;
nextP[8][17] = P[8][17] + P[5][17] * dt;
nextP[9][17] = P[9][17];
nextP[10][17] = P[10][17];
nextP[11][17] = P[11][17];
nextP[12][17] = P[12][17];
nextP[13][17] = P[13][17];
nextP[14][17] = P[14][17];
nextP[15][17] = P[15][17];
nextP[16][17] = P[16][17];
nextP[17][17] = P[17][17];
nextP[0][18] = P[0][18] * SPP[5] - P[1][18] * SPP[4] + P[2][18] * SPP[7] + P[9][18] * SPP[22] + P[12][18] * SPP[18];
nextP[1][18] = P[1][18] * SPP[6] - P[0][18] * SPP[2] - P[2][18] * SPP[8] + P[10][18] * SPP[22] + P[13][18] * SPP[17];
nextP[2][18] = P[0][18] * SPP[14] - P[1][18] * SPP[3] + P[2][18] * SPP[13] + P[11][18] * SPP[22] + P[14][18] * SPP[16];
nextP[3][18] = P[3][18] + P[0][18] * SPP[1] + P[1][18] * SPP[19] + P[2][18] * SPP[15] - P[15][18] * SPP[21];
nextP[4][18] = P[4][18] + P[15][18] * SF[22] + P[0][18] * SPP[20] + P[1][18] * SPP[12] + P[2][18] * SPP[11];
nextP[5][18] = P[5][18] + P[15][18] * SF[20] - P[0][18] * SPP[9] + P[1][18] * SPP[10] + P[2][18] * SPP[0];
nextP[6][18] = P[6][18] + P[3][18] * dt;
nextP[7][18] = P[7][18] + P[4][18] * dt;
nextP[8][18] = P[8][18] + P[5][18] * dt;
nextP[9][18] = P[9][18];
nextP[10][18] = P[10][18];
nextP[11][18] = P[11][18];
nextP[12][18] = P[12][18];
nextP[13][18] = P[13][18];
nextP[14][18] = P[14][18];
nextP[15][18] = P[15][18];
nextP[16][18] = P[16][18];
nextP[17][18] = P[17][18];
nextP[18][18] = P[18][18];
nextP[0][19] = P[0][19] * SPP[5] - P[1][19] * SPP[4] + P[2][19] * SPP[7] + P[9][19] * SPP[22] + P[12][19] * SPP[18];
nextP[1][19] = P[1][19] * SPP[6] - P[0][19] * SPP[2] - P[2][19] * SPP[8] + P[10][19] * SPP[22] + P[13][19] * SPP[17];
nextP[2][19] = P[0][19] * SPP[14] - P[1][19] * SPP[3] + P[2][19] * SPP[13] + P[11][19] * SPP[22] + P[14][19] * SPP[16];
nextP[3][19] = P[3][19] + P[0][19] * SPP[1] + P[1][19] * SPP[19] + P[2][19] * SPP[15] - P[15][19] * SPP[21];
nextP[4][19] = P[4][19] + P[15][19] * SF[22] + P[0][19] * SPP[20] + P[1][19] * SPP[12] + P[2][19] * SPP[11];
nextP[5][19] = P[5][19] + P[15][19] * SF[20] - P[0][19] * SPP[9] + P[1][19] * SPP[10] + P[2][19] * SPP[0];
nextP[6][19] = P[6][19] + P[3][19] * dt;
nextP[7][19] = P[7][19] + P[4][19] * dt;
nextP[8][19] = P[8][19] + P[5][19] * dt;
nextP[9][19] = P[9][19];
nextP[10][19] = P[10][19];
nextP[11][19] = P[11][19];
nextP[12][19] = P[12][19];
nextP[13][19] = P[13][19];
nextP[14][19] = P[14][19];
nextP[15][19] = P[15][19];
nextP[16][19] = P[16][19];
nextP[17][19] = P[17][19];
nextP[18][19] = P[18][19];
nextP[19][19] = P[19][19];
nextP[0][20] = P[0][20] * SPP[5] - P[1][20] * SPP[4] + P[2][20] * SPP[7] + P[9][20] * SPP[22] + P[12][20] * SPP[18];
nextP[1][20] = P[1][20] * SPP[6] - P[0][20] * SPP[2] - P[2][20] * SPP[8] + P[10][20] * SPP[22] + P[13][20] * SPP[17];
nextP[2][20] = P[0][20] * SPP[14] - P[1][20] * SPP[3] + P[2][20] * SPP[13] + P[11][20] * SPP[22] + P[14][20] * SPP[16];
nextP[3][20] = P[3][20] + P[0][20] * SPP[1] + P[1][20] * SPP[19] + P[2][20] * SPP[15] - P[15][20] * SPP[21];
nextP[4][20] = P[4][20] + P[15][20] * SF[22] + P[0][20] * SPP[20] + P[1][20] * SPP[12] + P[2][20] * SPP[11];
nextP[5][20] = P[5][20] + P[15][20] * SF[20] - P[0][20] * SPP[9] + P[1][20] * SPP[10] + P[2][20] * SPP[0];
nextP[6][20] = P[6][20] + P[3][20] * dt;
nextP[7][20] = P[7][20] + P[4][20] * dt;
nextP[8][20] = P[8][20] + P[5][20] * dt;
nextP[9][20] = P[9][20];
nextP[10][20] = P[10][20];
nextP[11][20] = P[11][20];
nextP[12][20] = P[12][20];
nextP[13][20] = P[13][20];
nextP[14][20] = P[14][20];
nextP[15][20] = P[15][20];
nextP[16][20] = P[16][20];
nextP[17][20] = P[17][20];
nextP[18][20] = P[18][20];
nextP[19][20] = P[19][20];
nextP[20][20] = P[20][20];
nextP[0][21] = P[0][21] * SPP[5] - P[1][21] * SPP[4] + P[2][21] * SPP[7] + P[9][21] * SPP[22] + P[12][21] * SPP[18];
nextP[1][21] = P[1][21] * SPP[6] - P[0][21] * SPP[2] - P[2][21] * SPP[8] + P[10][21] * SPP[22] + P[13][21] * SPP[17];
nextP[2][21] = P[0][21] * SPP[14] - P[1][21] * SPP[3] + P[2][21] * SPP[13] + P[11][21] * SPP[22] + P[14][21] * SPP[16];
nextP[3][21] = P[3][21] + P[0][21] * SPP[1] + P[1][21] * SPP[19] + P[2][21] * SPP[15] - P[15][21] * SPP[21];
nextP[4][21] = P[4][21] + P[15][21] * SF[22] + P[0][21] * SPP[20] + P[1][21] * SPP[12] + P[2][21] * SPP[11];
nextP[5][21] = P[5][21] + P[15][21] * SF[20] - P[0][21] * SPP[9] + P[1][21] * SPP[10] + P[2][21] * SPP[0];
nextP[6][21] = P[6][21] + P[3][21] * dt;
nextP[7][21] = P[7][21] + P[4][21] * dt;
nextP[8][21] = P[8][21] + P[5][21] * dt;
nextP[9][21] = P[9][21];
nextP[10][21] = P[10][21];
nextP[11][21] = P[11][21];
nextP[12][21] = P[12][21];
nextP[13][21] = P[13][21];
nextP[14][21] = P[14][21];
nextP[15][21] = P[15][21];
nextP[16][21] = P[16][21];
nextP[17][21] = P[17][21];
nextP[18][21] = P[18][21];
nextP[19][21] = P[19][21];
nextP[20][21] = P[20][21];
nextP[21][21] = P[21][21];
}
// Don't do covariance prediction on wind states unless we are using them
if (_control_status.flags.wind) {
// Check if we have jsut transitioned to using wind states and set the variances accordingly
if (!_control_status_prev.flags.mag_3D) {
for (uint8_t index = 22; index <= 23; index++) {
// TODO initialise wind states using ground speed and airspeed and set initial variance using sum of ground speed and airspeed variances
P[index][index] = sq(5.0f);
}
}
nextP[0][22] = P[0][22] * SPP[5] - P[1][22] * SPP[4] + P[2][22] * SPP[7] + P[9][22] * SPP[22] + P[12][22] * SPP[18];
nextP[1][22] = P[1][22] * SPP[6] - P[0][22] * SPP[2] - P[2][22] * SPP[8] + P[10][22] * SPP[22] + P[13][22] * SPP[17];
nextP[2][22] = P[0][22] * SPP[14] - P[1][22] * SPP[3] + P[2][22] * SPP[13] + P[11][22] * SPP[22] + P[14][22] * SPP[16];
nextP[3][22] = P[3][22] + P[0][22] * SPP[1] + P[1][22] * SPP[19] + P[2][22] * SPP[15] - P[15][22] * SPP[21];
nextP[4][22] = P[4][22] + P[15][22] * SF[22] + P[0][22] * SPP[20] + P[1][22] * SPP[12] + P[2][22] * SPP[11];
nextP[5][22] = P[5][22] + P[15][22] * SF[20] - P[0][22] * SPP[9] + P[1][22] * SPP[10] + P[2][22] * SPP[0];
nextP[6][22] = P[6][22] + P[3][22] * dt;
nextP[7][22] = P[7][22] + P[4][22] * dt;
nextP[8][22] = P[8][22] + P[5][22] * dt;
nextP[9][22] = P[9][22];
nextP[10][22] = P[10][22];
nextP[11][22] = P[11][22];
nextP[12][22] = P[12][22];
nextP[13][22] = P[13][22];
nextP[14][22] = P[14][22];
nextP[15][22] = P[15][22];
nextP[16][22] = P[16][22];
nextP[17][22] = P[17][22];
nextP[18][22] = P[18][22];
nextP[19][22] = P[19][22];
nextP[20][22] = P[20][22];
nextP[21][22] = P[21][22];
nextP[22][22] = P[22][22];
nextP[0][23] = P[0][23] * SPP[5] - P[1][23] * SPP[4] + P[2][23] * SPP[7] + P[9][23] * SPP[22] + P[12][23] * SPP[18];
nextP[1][23] = P[1][23] * SPP[6] - P[0][23] * SPP[2] - P[2][23] * SPP[8] + P[10][23] * SPP[22] + P[13][23] * SPP[17];
nextP[2][23] = P[0][23] * SPP[14] - P[1][23] * SPP[3] + P[2][23] * SPP[13] + P[11][23] * SPP[22] + P[14][23] * SPP[16];
nextP[3][23] = P[3][23] + P[0][23] * SPP[1] + P[1][23] * SPP[19] + P[2][23] * SPP[15] - P[15][23] * SPP[21];
nextP[4][23] = P[4][23] + P[15][23] * SF[22] + P[0][23] * SPP[20] + P[1][23] * SPP[12] + P[2][23] * SPP[11];
nextP[5][23] = P[5][23] + P[15][23] * SF[20] - P[0][23] * SPP[9] + P[1][23] * SPP[10] + P[2][23] * SPP[0];
nextP[6][23] = P[6][23] + P[3][23] * dt;
nextP[7][23] = P[7][23] + P[4][23] * dt;
nextP[8][23] = P[8][23] + P[5][23] * dt;
nextP[9][23] = P[9][23];
nextP[10][23] = P[10][23];
nextP[11][23] = P[11][23];
nextP[12][23] = P[12][23];
nextP[13][23] = P[13][23];
nextP[14][23] = P[14][23];
nextP[15][23] = P[15][23];
nextP[16][23] = P[16][23];
nextP[17][23] = P[17][23];
nextP[18][23] = P[18][23];
nextP[19][23] = P[19][23];
nextP[20][23] = P[20][23];
nextP[21][23] = P[21][23];
nextP[22][23] = P[22][23];
nextP[23][23] = P[23][23];
}
// add process noise
for (unsigned i = 0; i < _k_num_states; i++) {
@@ -664,7 +721,7 @@ void Ekf::predictCovariance()
}
// stop position covariance growth if our total position variance reaches 100m
// this can happen if we loose gps for some time
// this can happen if we lose gps for some time
if ((P[6][6] + P[7][7]) > 1e4f) {
for (uint8_t i = 6; i < 8; i++) {
for (uint8_t j = 0; j < _k_num_states; j++) {
@@ -681,10 +738,12 @@ void Ekf::predictCovariance()
}
}
// copy variances (diagonals)
for (unsigned i = 0; i < _k_num_states; i++) {
P[i][i] = nextP[i][i];
}
// force symmetry
for (unsigned row = 1; row < _k_num_states; row++) {
for (unsigned column = 0; column < row; column++) {
P[row][column] = 0.5f * (nextP[row][column] + nextP[column][row]);
@@ -706,8 +765,8 @@ void Ekf::limitCov()
P_lim[3] = 0.001f; // gyro bias max var
P_lim[4] = 0.01f; // gyro scale max var
P_lim[5] = 0.1f; // delta velocity z bias max var
P_lim[6] = 0.01f; // earth mag field max var
P_lim[7] = 0.01f; // body mag field max var
P_lim[6] = 0.1f; // earth mag field max var
P_lim[7] = 0.1f; // body mag field max var
P_lim[8] = 1000.0f; // wind max var
for (int i = 0; i < 3; i++) {
@@ -742,20 +801,14 @@ void Ekf::limitCov()
math::constrain(P[15][15], 0.0f, P_lim[5]);
for (int i = 16; i < 19; i++) {
math::constrain(P[i][i], 0.0f, P_lim[6]);
}
for (int i = 19; i < 22; i++) {
math::constrain(P[i][i], 0.0f, P_lim[7]);
}
for (int i = 22; i < 24; i++) {
math::constrain(P[i][i], 0.0f, P_lim[8]);
}
}
+4
View File
@@ -85,8 +85,12 @@ public:
bool collect_gps(uint64_t time_usec, struct gps_message *gps);
bool collect_imu(imuSample &imu);
// this is the current status of the filter control modes
filter_control_status_u _control_status = {};
// this is the previous status of the filter control modes - used to detect mode transitions
filter_control_status_u _control_status_prev = {};
// get the ekf WGS-84 origin position and height and the system time it was last set
void get_ekf_origin(uint64_t *origin_time, map_projection_reference_s *origin_pos, float *origin_alt);
+168 -115
View File
@@ -284,10 +284,18 @@ void Ekf::fuseMag()
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]);
// Don't update wind states unless we are doing wind estimation
if (_control_status.flags.wind) {
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 {
Kfusion[22] = 0.0f;
Kfusion[23] = 0.0f;
}
} else if (index == 1) {
// Calculate Y axis Kalman gains
@@ -340,10 +348,18 @@ void Ekf::fuseMag()
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]);
// Don't update wind states unless we are doing wind estimation
if (_control_status.flags.wind) {
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 {
Kfusion[22] = 0.0f;
Kfusion[23] = 0.0f;
}
} else if (index == 2) {
// Calculate Z axis Kalman gains
@@ -396,10 +412,18 @@ void Ekf::fuseMag()
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]);
// Don't update wind states unless we are doing wind estimation
if (_control_status.flags.wind) {
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 {
Kfusion[22] = 0.0f;
Kfusion[23] = 0.0f;
}
} else {
return;
@@ -468,73 +492,71 @@ void Ekf::fuseHeading()
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 = fmaxf(_params.mag_heading_noise, 1.0e-2f);
R_mag = R_mag * R_mag;
float R_YAW = fmaxf(_params.mag_heading_noise, 1.0e-2f);
R_YAW = R_YAW * R_YAW;
// calculate intermediate variables for observation jacobian
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 t6 = t2 + t3 - t4 - t5;
float t7 = q0 * q3 * 2.0f;
float t8 = q1 * q2 * 2.0f;
float t9 = t7 + t8;
float t10;
float H_HDG[3] = {};
H_HDG[0] = -t31 * (t20 * (magZ * t16 + magY * t18) + t25 * t27 * (magY * t8 + magZ * t10));
H_HDG[1] = t31 * (t20 * (magX * t18 + magZ * t22) + t25 * t27 * (magX * t8 - magZ * t11));
H_HDG[2] = t31 * (t20 * (magX * t16 - magY * t22) + t25 * t27 * (magX * t10 + magY * t11));
if (fabsf(t6) > 1e-6f) {
t10 = 1.0f / (t6 * t6);
} else {
return;
}
float t11 = t9 * t9;
float t12 = t10 * t11;
float t13 = t12 + 1.0f;
float t14;
if (fabsf(t13) > 1e-6f) {
t14 = 1.0f / t13;
} else {
return;
}
float t15 = 1.0f / t6;
// calculate observation jacobian
float H_YAW[3] = {};
H_YAW[1] = t14 * (t15 * (q0 * q1 * 2.0f - q2 * q3 * 2.0f) + t9 * t10 * (q0 * q2 * 2.0f + q1 * q3 * 2.0f));
H_YAW[2] = t14 * (t15 * (t2 - t3 + t4 - t5) + t9 * t10 * (t7 - t8));
// calculate innovation
// rotate body field magnetic field measurement into earth frame and compare to published declination to get heading measurement
// TODO - enable use of an off-board heading measurement
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)) - _mag_declination;
innovation = math::constrain(innovation, -0.5f, 0.5f);
// wrap the innovation to the interval between +-pi
innovation = matrix::wrap_pi(innovation);
_heading_innov = innovation;
float innovation_var = R_mag;
_heading_innov_var = innovation_var;
// calculate innovation variance
float innovation_var = R_YAW;
_heading_innov_var = innovation_var;
float PH[3] = {};
for (unsigned row = 0; row < 3; row++) {
for (unsigned column = 0; column < 3; column++) {
PH[row] += P[row][column] * H_HDG[column];
PH[row] += P[row][column] * H_YAW[column];
}
innovation_var += H_HDG[row] * PH[row];
innovation_var += H_YAW[row] * PH[row];
}
if (innovation_var >= R_mag) {
if (innovation_var >= R_YAW) {
// the innovation variance contribution from the state covariances is not negative, no fault
_fault_status.bad_mag_hdg = false;
@@ -547,19 +569,42 @@ void Ekf::fuseHeading()
return;
}
float innovation_var_inv = 1 / innovation_var;
float innovation_var_inv = 1.0f / innovation_var;
// calculate kalman gain
// calculate the kalman gains taking dvantage of the reduce size of H_YAW
float Kfusion[_k_num_states] = {};
for (unsigned row = 0; row < _k_num_states; row++) {
// gains for states that are always used
for (unsigned row = 0; row <= 15; row++) {
for (unsigned column = 0; column < 3; column++) {
Kfusion[row] += P[row][column] * H_HDG[column];
Kfusion[row] += P[row][column] * H_YAW[column];
}
Kfusion[row] *= innovation_var_inv;
}
// only calculate gains for magnetic field states if they are being used
if (_control_status.flags.mag_3D) {
for (unsigned row = 16; row <= 21; row++) {
for (unsigned column = 0; column < 3; column++) {
Kfusion[row] += P[row][column] * H_YAW[column];
}
Kfusion[row] *= innovation_var_inv;
}
}
// only calculate gains for wind states if they are being used
if (_control_status.flags.wind) {
for (unsigned row = 22; row <= 23; row++) {
for (unsigned column = 0; column < 3; column++) {
Kfusion[row] += P[row][column] * H_YAW[column];
}
Kfusion[row] *= innovation_var_inv;
}
}
// innovation test ratio
_yaw_test_ratio = sq(innovation) / (sq(math::max(_params.heading_innov_gate, 1.0f)) * innovation_var);
@@ -572,12 +617,18 @@ void Ekf::fuseHeading()
// by interference or a large initial gyro bias
if (_control_status.flags.in_air) {
return;
} else {
// constrain the innovation to the maximum set by the gate
float gate_limit = sqrtf((sq(math::max(_params.heading_innov_gate, 1.0f)) * innovation_var));
innovation = math::constrain(innovation, -gate_limit, gate_limit);
}
} else {
_mag_healthy = true;
}
// zero the attitude error states and use the kalman gain vector and innovation to update the states
_state.ang_error.setZero();
fuse(Kfusion, innovation);
@@ -587,11 +638,12 @@ void Ekf::fuseHeading()
_state.quat_nominal = dq * _state.quat_nominal;
_state.quat_nominal.normalize();
// update the covariance matrix taking advantage of the reduced size of H_YAW
float HP[_k_num_states] = {};
for (unsigned column = 0; column < _k_num_states; column++) {
for (unsigned row = 0; row < 3; row++) {
HP[column] += H_HDG[row] * P[row][column];
HP[column] += H_YAW[row] * P[row][column];
}
}
@@ -615,30 +667,28 @@ void Ekf::fuseDeclination()
// Calculate intermediate variables
// if the horizontal magnetic field is too small, this calculation will be badly conditioned
if (fabsf(magN) < 0.001f) {
if (magN < 0.001f) {
return;
}
float t2 = 1.0f / magN;
float t4 = magE * t2;
float t3 = tanf(t4);
float t5 = t3 * t3;
float t6 = t5 + 1.0f;
float t25 = t2 * t6;
float t7 = 1.0f / (magN * magN);
float t26 = magE * t6 * t7;
float t8 = P[17][17] * t25;
float t15 = P[16][17] * t26;
float t9 = t8 - t15;
float t10 = t25 * t9;
float t11 = P[17][16] * t25;
float t16 = P[16][16] * t26;
float t12 = t11 - t16;
float t17 = t26 * t12;
float t13 = R_DECL + t10 - t17; // innovation variance
float t2 = magE * magE;
float t3 = magN * magN;
float t4 = t2 + t3;
float t5 = 1.0f / t4;
float t22 = magE * t5;
float t23 = magN * t5;
float t6 = P[16][16] * t22;
float t13 = P[17][16] * t23;
float t7 = t6 - t13;
float t8 = t22 * t7;
float t9 = P[16][17] * t22;
float t14 = P[17][17] * t23;
float t10 = t9 - t14;
float t15 = t23 * t10;
float t11 = R_DECL + t8 - t15; // innovation variance
// check the innovation variance calculation for a badly conditioned covariance matrix
if (t13 >= R_DECL) {
if (t11 >= R_DECL) {
// the innovation variance contribution from the state covariances is not negative, no fault
_fault_status.bad_mag_decl = false;
@@ -651,50 +701,53 @@ void Ekf::fuseDeclination()
return;
}
float t14 = 1.0f / t13;
float t18 = magE;
float t19 = magN;
float t21 = 1.0f / t19;
float t22 = t18 * t21;
float t20 = tanf(t22);
float t23 = t20 * t20;
float t24 = t23 + 1.0f;
float t12 = 1.0f / t11;
// Calculate the observation Jacobian
// Note only 2 terms are non-zero which can be used in matrix operations for calculation of Kalman gains and covariance update to significantly reduce cost
float H_DECL[24] = {};
H_DECL[16] = -t18 * 1.0f / (t19 * t19) * t24;
H_DECL[17] = t21 * t24;
H_DECL[16] = -magE * t5;
H_DECL[17] = magN * t5;
// Calculate the Kalman gains
float Kfusion[_k_num_states] = {};
Kfusion[0] = t14 * (P[0][17] * t25 - P[0][16] * t26);
Kfusion[1] = t14 * (P[1][17] * t25 - P[1][16] * t26);
Kfusion[2] = t14 * (P[2][17] * t25 - P[2][16] * t26);
Kfusion[3] = t14 * (P[3][17] * t25 - P[3][16] * t26);
Kfusion[4] = t14 * (P[4][17] * t25 - P[4][16] * t26);
Kfusion[5] = t14 * (P[5][17] * t25 - P[5][16] * t26);
Kfusion[6] = t14 * (P[6][17] * t25 - P[6][16] * t26);
Kfusion[7] = t14 * (P[7][17] * t25 - P[7][16] * t26);
Kfusion[8] = t14 * (P[8][17] * t25 - P[8][16] * t26);
Kfusion[9] = t14 * (P[9][17] * t25 - P[9][16] * t26);
Kfusion[10] = t14 * (P[10][17] * t25 - P[10][16] * t26);
Kfusion[11] = t14 * (P[11][17] * t25 - P[11][16] * t26);
Kfusion[12] = t14 * (P[12][17] * t25 - P[12][16] * t26);
Kfusion[13] = t14 * (P[13][17] * t25 - P[13][16] * t26);
Kfusion[14] = t14 * (P[14][17] * t25 - P[14][16] * t26);
Kfusion[15] = t14 * (P[15][17] * t25 - P[15][16] * t26);
Kfusion[16] = -t14 * (t16 - P[16][17] * t25);
Kfusion[17] = t14 * (t8 - P[17][16] * t26);
Kfusion[18] = t14 * (P[18][17] * t25 - P[18][16] * t26);
Kfusion[19] = t14 * (P[19][17] * t25 - P[19][16] * t26);
Kfusion[20] = t14 * (P[20][17] * t25 - P[20][16] * t26);
Kfusion[21] = t14 * (P[21][17] * t25 - P[21][16] * t26);
Kfusion[22] = t14 * (P[22][17] * t25 - P[22][16] * t26);
Kfusion[23] = t14 * (P[23][17] * t25 - P[23][16] * t26);
Kfusion[0] = -t12 * (P[0][16] * t22 - P[0][17] * t23);
Kfusion[1] = -t12 * (P[1][16] * t22 - P[1][17] * t23);
Kfusion[2] = -t12 * (P[2][16] * t22 - P[2][17] * t23);
Kfusion[3] = -t12 * (P[3][16] * t22 - P[3][17] * t23);
Kfusion[4] = -t12 * (P[4][16] * t22 - P[4][17] * t23);
Kfusion[5] = -t12 * (P[5][16] * t22 - P[5][17] * t23);
Kfusion[6] = -t12 * (P[6][16] * t22 - P[6][17] * t23);
Kfusion[7] = -t12 * (P[7][16] * t22 - P[7][17] * t23);
Kfusion[8] = -t12 * (P[8][16] * t22 - P[8][17] * t23);
Kfusion[9] = -t12 * (P[9][16] * t22 - P[9][17] * t23);
Kfusion[10] = -t12 * (P[10][16] * t22 - P[10][17] * t23);
Kfusion[11] = -t12 * (P[11][16] * t22 - P[11][17] * t23);
Kfusion[12] = -t12 * (P[12][16] * t22 - P[12][17] * t23);
Kfusion[13] = -t12 * (P[13][16] * t22 - P[13][17] * t23);
Kfusion[14] = -t12 * (P[14][16] * t22 - P[14][17] * t23);
Kfusion[15] = -t12 * (P[15][16] * t22 - P[15][17] * t23);
// We only do declination fusion when we are using all the field states, so no logic required here
Kfusion[16] = -t12 * (t6 - P[16][17] * t23);
Kfusion[17] = t12 * (t14 - P[17][16] * t22);
Kfusion[18] = -t12 * (P[18][16] * t22 - P[18][17] * t23);
Kfusion[19] = -t12 * (P[19][16] * t22 - P[19][17] * t23);
Kfusion[20] = -t12 * (P[20][16] * t22 - P[20][17] * t23);
Kfusion[21] = -t12 * (P[21][16] * t22 - P[21][17] * t23);
// Don't update wind states unless we are doing wind estimation
if (_control_status.flags.wind) {
Kfusion[22] = -t12 * (P[22][16] * t22 - P[22][17] * t23);
Kfusion[23] = -t12 * (P[23][16] * t22 - P[23][17] * t23);
} else {
Kfusion[22] = 0.0f;
Kfusion[23] = 0.0f;
}
// calculate innovation and constrain
float innovation = atanf(t4) - _mag_declination;
float innovation = atanf(magE / magN) - _mag_declination;
innovation = math::constrain(innovation, -0.5f, 0.5f);
// zero attitude error states and perform the state correction
+22 -2
View File
@@ -153,9 +153,29 @@ void Ekf::fuseVelPosHeight()
unsigned state_index = obs_index + 3; // we start with vx and this is the 4. state
// calculate kalman gain K = PHS, where S = 1/innovation variance
for (int row = 0; row < 24; row++) {
Kfusion[row] = P[row][state_index] / _vel_pos_innov_var[obs_index];
for (int row = 0; row <= 15; row++) {
Kfusion[row] = P[row][state_index] / _vel_pos_innov_var[obs_index];
}
// only update magnetic field states if we are fusing 3-axis observations
if (_control_status.flags.mag_3D) {
for (int row = 16; row <= 21; row++) {
Kfusion[row] = P[row][state_index] / _vel_pos_innov_var[obs_index];
}
} else {
for (int row = 16; row <= 21; row++) {
Kfusion[row] = 0.0f;
}
}
// only update wind states if we are doing wind estimation
if (_control_status.flags.wind) {
for (int row = 22; row <= 23; row++) {
Kfusion[row] = P[row][state_index] / _vel_pos_innov_var[obs_index];
}
} else {
for (int row = 22; row <= 23; row++) {
Kfusion[row] = 0.0f;
}
}
// by definition the angle error state is zero at the fusion time
_state.ang_error.setZero();
@@ -9,62 +9,56 @@ declinationAngle is the estimated declination as that location
This fusion method is used to constrain the rotation of the earth field vector when there are no earth relative measurements
(e.g. using optical flow without GPS, or when the vehicle is stationary) to provide an absolute yaw reference. In this situation the presence of yaw gyro errors
can cause the magnetic declination of the earth field estimates to slowly rotate.
Divide by zero protection and protection against a badly conditioned covariance matrix must be included.
*/
// Calculate intermediate variable
float t2 = 1.0f/magN;
float t4 = magE*t2;
float t3 = tanf(t4);
float t5 = t3*t3;
float t6 = t5+1.0f;
float t25 = t2*t6;
float t7 = 1.0f/(magN*magN);
float t26 = magE*t6*t7;
float t8 = P[17][17]*t25;
float t15 = P[16][17]*t26;
float t9 = t8-t15;
float t10 = t25*t9;
float t11 = P[17][16]*t25;
float t16 = P[16][16]*t26;
float t12 = t11-t16;
float t17 = t26*t12;
float t13 = R_DECL+t10-t17;
float t14 = 1.0f/t13;
float t18 = magE;
float t19 = magN;
float t21 = 1.0f/t19;
float t22 = t18*t21;
float t20 = tanf(t22);
float t23 = t20*t20;
float t24 = t23+1.0f;
float t2 = magE*magE;
float t3 = magN*magN;
float t4 = t2+t3;
float t5 = 1.0f/t4;
float t22 = magE*t5;
float t23 = magN*t5;
float t6 = P[16][16]*t22;
float t13 = P[17][16]*t23;
float t7 = t6-t13;
float t8 = t22*t7;
float t9 = P[16][17]*t22;
float t14 = P[17][17]*t23;
float t10 = t9-t14;
float t15 = t23*t10;
float t11 = R_DECL+t8-t15; // innovation variance
float t12 = 1.0f/t11;
// Calculate the observation Jacobian
// Note only 2 terms are non-zero which can be used in matrix operations for calculation of Kalman gains and covariance update to significantly reduce cost
H_MAG[16] = -t18*1.0f/(t19*t19)*t24;
H_MAG[17] = t21*t24;
H_DECL[16] = -magE*t5;
H_DECL[17] = magN*t5;
// Calculate the Kalman gains
Kfusion[0] = t14*(P[0][17]*t25-P[0][16]*t26);
Kfusion[1] = t14*(P[1][17]*t25-P[1][16]*t26);
Kfusion[2] = t14*(P[2][17]*t25-P[2][16]*t26);
Kfusion[3] = t14*(P[3][17]*t25-P[3][16]*t26);
Kfusion[4] = t14*(P[4][17]*t25-P[4][16]*t26);
Kfusion[5] = t14*(P[5][17]*t25-P[5][16]*t26);
Kfusion[6] = t14*(P[6][17]*t25-P[6][16]*t26);
Kfusion[7] = t14*(P[7][17]*t25-P[7][16]*t26);
Kfusion[8] = t14*(P[8][17]*t25-P[8][16]*t26);
Kfusion[9] = t14*(P[9][17]*t25-P[9][16]*t26);
Kfusion[10] = t14*(P[10][17]*t25-P[10][16]*t26);
Kfusion[11] = t14*(P[11][17]*t25-P[11][16]*t26);
Kfusion[12] = t14*(P[12][17]*t25-P[12][16]*t26);
Kfusion[13] = t14*(P[13][17]*t25-P[13][16]*t26);
Kfusion[14] = t14*(P[14][17]*t25-P[14][16]*t26);
Kfusion[15] = t14*(P[15][17]*t25-P[15][16]*t26);
Kfusion[16] = -t14*(t16-P[16][17]*t25);
Kfusion[17] = t14*(t8-P[17][16]*t26);
Kfusion[18] = t14*(P[18][17]*t25-P[18][16]*t26);
Kfusion[19] = t14*(P[19][17]*t25-P[19][16]*t26);
Kfusion[20] = t14*(P[20][17]*t25-P[20][16]*t26);
Kfusion[21] = t14*(P[21][17]*t25-P[21][16]*t26);
Kfusion[22] = t14*(P[22][17]*t25-P[22][16]*t26);
Kfusion[23] = t14*(P[23][17]*t25-P[23][16]*t26);
Kfusion[0] = -t12*(P[0][16]*t22-P[0][17]*t23);
Kfusion[1] = -t12*(P[1][16]*t22-P[1][17]*t23);
Kfusion[2] = -t12*(P[2][16]*t22-P[2][17]*t23);
Kfusion[3] = -t12*(P[3][16]*t22-P[3][17]*t23);
Kfusion[4] = -t12*(P[4][16]*t22-P[4][17]*t23);
Kfusion[5] = -t12*(P[5][16]*t22-P[5][17]*t23);
Kfusion[6] = -t12*(P[6][16]*t22-P[6][17]*t23);
Kfusion[7] = -t12*(P[7][16]*t22-P[7][17]*t23);
Kfusion[8] = -t12*(P[8][16]*t22-P[8][17]*t23);
Kfusion[9] = -t12*(P[9][16]*t22-P[9][17]*t23);
Kfusion[10] = -t12*(P[10][16]*t22-P[10][17]*t23);
Kfusion[11] = -t12*(P[11][16]*t22-P[11][17]*t23);
Kfusion[12] = -t12*(P[12][16]*t22-P[12][17]*t23);
Kfusion[13] = -t12*(P[13][16]*t22-P[13][17]*t23);
Kfusion[14] = -t12*(P[14][16]*t22-P[14][17]*t23);
Kfusion[15] = -t12*(P[15][16]*t22-P[15][17]*t23);
Kfusion[16] = -t12*(t6-P[16][17]*t23);
Kfusion[17] = t12*(t14-P[17][16]*t22);
Kfusion[18] = -t12*(P[18][16]*t22-P[18][17]*t23);
Kfusion[19] = -t12*(P[19][16]*t22-P[19][17]*t23);
Kfusion[20] = -t12*(P[20][16]*t22-P[20][17]*t23);
Kfusion[21] = -t12*(P[21][16]*t22-P[21][17]*t23);
Kfusion[22] = -t12*(P[22][16]*t22-P[22][17]*t23);
Kfusion[23] = -t12*(P[23][16]*t22-P[23][17]*t23);
@@ -5,6 +5,8 @@ innovation = atan2f(magMeasEarthFrameEast,magMeasEarthFrameNorth) - declinationA
magMeasEarthFrameEast and magMeasEarthFrameNorth are obtained by rotating the magnetometer measurements from body frame to eath frame.
declinationAngle is the estimated declination as that location
Protection against /0 and covariance matrix errors will need to be added.
*/
// intermediate variables
@@ -12,36 +14,19 @@ 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 t6 = t2+t3-t4-t5;
float t7 = q0*q3*2.0f;
float t8 = q1*q2*2.0f;
float t9 = t7+t8;
float t10 = 1.0f/(t6*t6);
float t11 = t9*t9;
float t12 = t10*t11;
float t13 = t12+1.0f;
float t14 = 1.0f/t13;
float t15 = 1.0f/t6;
// Calculate the observation jacobian for the innovation derivative wrt the attitude error states only
// Use the reduced order to optimise the calculation of the Kalman gain matrix and covariance update
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));
H_YAW[1] = t14*(t15*(q0*q1*2.0f-q2*q3*2.0f)+t9*t10*(q0*q2*2.0f+q1*q3*2.0f));
H_YAW[2] = t14*(t15*(t2-t3+t4-t5)+t9*t10*(t7-t8));
@@ -68,7 +68,7 @@ syms R_LOS real % variance of LOS angular rate mesurements (rad/sec)^2
syms ptd real % location of terrain in D axis
syms rotErrX rotErrY rotErrZ real; % error rotation vector in body frame
syms decl real; % earth magnetic field declination from true north
syms R_MAGS real; % variance for magnetic deviation measurement
syms R_YAW real; % variance for magnetic deviation measurement
syms R_DECL real; % variance of supplied declination
syms BCXinv BCYinv real % inverse of ballistic coefficient for wind relative movement along the x and y body axes
syms rho real % air density (kg/m^3)
@@ -269,19 +269,22 @@ ccode(H_LOS,'file','H_LOS.txt');
ccode(K_LOSX,'file','K_LOSX.txt');
ccode(K_LOSY,'file','K_LOSY.txt');
%% derive equations for fusion of magnetic heading measurement
%% derive equations for fusion of direct yaw measurement
% rotate magnetic field into earth axes
magMeasNED = Tbn*[magX;magY;magZ];
% the predicted measurement is the angle wrt magnetic north of the horizontal
% component of the measured field
angMeas = tan(magMeasNED(2)/magMeasNED(1)) - decl;
H_MAGS = jacobian(angMeas,errRotVec); % measurement Jacobian
% rotate X body axis into earth axes
yawVec = Tbn*[1;0;0];
% Calculate the yaw angle of the projection
angMeas = atan(yawVec(2)/yawVec(1));
H_YAW = jacobian(angMeas,stateVector); % measurement Jacobian
%H_MAGS = H_MAGS(1:3);
H_MAGS = subs(H_MAGS, {'rotErrX', 'rotErrY', 'rotErrZ'}, {0,0,0});
H_MAGS = simplify(H_MAGS);
H_YAW = subs(H_YAW, {'rotErrX', 'rotErrY', 'rotErrZ'}, {0,0,0});
H_YAW = simplify(H_YAW);
%[H_MAGS,SH_MAGS]=OptimiseAlgebra(H_MAGS,'SH_MAGS');
ccode(H_MAGS,'file','calcH_MAGS.c');
ccode(H_YAW,'file','calcH_YAW.c');
% Calculate Kalman gain vector
K_YAW = (P*transpose(H_YAW))/(H_YAW*P*transpose(H_YAW) + R_YAW);
%K_MAGS = simplify(K_MAGS);
ccode(K_YAW,'file','calcK_YAW.c');
%% derive equations for fusion of synthetic deviation measurement
% used to keep correct heading when operating without absolute position or
@@ -290,7 +293,7 @@ ccode(H_MAGS,'file','calcH_MAGS.c');
magMeasNED = [magN;magE;magD];
% the predicted measurement is the angle wrt magnetic north of the horizontal
% component of the measured field
angMeas = tan(magMeasNED(2)/magMeasNED(1));
angMeas = atan(magMeasNED(2)/magMeasNED(1));
H_MAGD = jacobian(angMeas,stateVector); % measurement Jacobian
H_MAGD = subs(H_MAGD, {'rotErrX', 'rotErrY', 'rotErrZ'}, {0,0,0});
H_MAGD = simplify(H_MAGD);