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EKF: Add missing Kalman gain to Declination fusion autocode

master
Paul Riseborough 9 years ago
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a22886544d
  1. 61
      matlab/generated/Inertial Nav EKF/Magnetic Declination Fusion.txt

61
matlab/generated/Inertial Nav EKF/Magnetic Declination Fusion.txt

@ -1,7 +1,7 @@
/* /*
Autocode for fusion of a magnetic declination estimate where the innovation is given by 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. magMeasEarthFrameEast and magMeasEarthFrameNorth are obtained by rotating the magnetometer measurements from body frame to earth frame.
declinationAngle is the estimated declination as that location 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. 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 // Calculate intermediate variable
// 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; 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);

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