EKF: Add missing Kalman gain to Declination fusion autocode

This commit is contained in:
Paul Riseborough
2016-02-08 14:02:08 +11:00
parent 2c8c6efb45
commit a22886544d
@@ -1,7 +1,7 @@
/*
Autocode for fusion of a magnetic declination estimate where the innovation is given by
innovation = atan2f(magMeasEarthFrameEast,magMeasEarthFrameNorth) - declinationAngle;
innovation = atanf(magMeasEarthFrameEast/magMeasEarthFrameNorth) - declinationAngle;
magMeasEarthFrameEast and magMeasEarthFrameNorth are obtained by rotating the magnetometer measurements from body frame to earth frame.
declinationAngle is the estimated declination as that location
@@ -11,5 +11,60 @@ This fusion method is used to constrain the rotation of the earth field vector w
can cause the magnetic declination of the earth field estimates to slowly rotate.
*/
// 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 t7 = 1.0f/(magN*magN);␍float t8 = P[17][17]*t2*t6;␍float t15 = P[16][17]*magE*t6*t7;␍float t9 = t8-t15;␍float t10 = t2*t6*t9;␍float t11 = P[17][16]*t2*t6;␍float t16 = P[16][16]*magE*t6*t7;␍float t12 = t11-t16;␍float t17 = magE*t6*t7*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;␍␍// 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_MAG[24];␍H_MAG[16] = -t18*1.0f/(t19*t19)*t24;␍H_MAG[17] = t21*t24;␍
// 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;
// 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;
// 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);