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AP_NavEKF2: fix scaling error in use of IMU noise parameters 

Also remove process noise from state transition matrix where it was mistakenly left in after the derivation
This commit is contained in:
Paul Riseborough 2016-05-08 22:47:01 +10:00 committed by Andrew Tridgell
parent 5461002eea
commit cf05e110fc
1 changed files with 8 additions and 8 deletions
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16
libraries/AP_NavEKF2/AP_NavEKF2_core.cpp
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@ -706,15 +706,15 @@ void NavEKF2_core::CovariancePrediction()
daz_s = stateStruct.gyro_scale.z; daz_s = stateStruct.gyro_scale.z;
dvz_b = stateStruct.accel_zbias; dvz_b = stateStruct.accel_zbias;
float _gyrNoise = constrain_float(frontend->_gyrNoise, 1e-4f, 1e-2f); float _gyrNoise = constrain_float(frontend->_gyrNoise, 1e-4f, 1e-2f);
daxNoise = dayNoise = dazNoise = dt*_gyrNoise;
float _accNoise = constrain_float(frontend->_accNoise, 1e-2f, 1.0f); float _accNoise = constrain_float(frontend->_accNoise, 1e-2f, 1.0f);
dvxNoise = dvyNoise = dvzNoise = dt*_accNoise; daxNoise = dayNoise = dazNoise = sq(dt*_gyrNoise);
dvxNoise = dvyNoise = dvzNoise = sq(dt*_accNoise);
// calculate the predicted covariance due to inertial sensor error propagation // calculate the predicted covariance due to inertial sensor error propagation
// we calculate the upper diagonal and copy to take advantage of symmetry // we calculate the upper diagonal and copy to take advantage of symmetry
SF[0] = daz_b/2 + dazNoise/2 - (daz*daz_s)/2; SF[0] = daz_b/2 - (daz*daz_s)/2;
SF[1] = day_b/2 + dayNoise/2 - (day*day_s)/2; SF[1] = day_b/2 - (day*day_s)/2;
SF[2] = dax_b/2 + daxNoise/2 - (dax*dax_s)/2; SF[2] = dax_b/2 - (dax*dax_s)/2;
SF[3] = q3/2 - (q0*SF[0])/2 + (q1*SF[1])/2 - (q2*SF[2])/2; SF[3] = q3/2 - (q0*SF[0])/2 + (q1*SF[1])/2 - (q2*SF[2])/2;
SF[4] = q0/2 - (q1*SF[2])/2 - (q2*SF[1])/2 + (q3*SF[0])/2; SF[4] = q0/2 - (q1*SF[2])/2 - (q2*SF[1])/2 + (q3*SF[0])/2;
SF[5] = q1/2 + (q0*SF[2])/2 - (q2*SF[0])/2 - (q3*SF[1])/2; SF[5] = q1/2 + (q0*SF[2])/2 - (q2*SF[0])/2 - (q3*SF[1])/2;
@ -728,9 +728,9 @@ void NavEKF2_core::CovariancePrediction()
SF[13] = q1/2 - (q0*SF[2])/2 + (q2*SF[0])/2 - (q3*SF[1])/2; SF[13] = q1/2 - (q0*SF[2])/2 + (q2*SF[0])/2 - (q3*SF[1])/2;
SF[14] = q3/2 + (q0*SF[0])/2 + (q1*SF[1])/2 + (q2*SF[2])/2; SF[14] = q3/2 + (q0*SF[0])/2 + (q1*SF[1])/2 + (q2*SF[2])/2;
SF[15] = - sq(q0) - sq(q1) - sq(q2) - sq(q3); SF[15] = - sq(q0) - sq(q1) - sq(q2) - sq(q3);
SF[16] = dvz_b - dvz + dvzNoise; SF[16] = dvz_b - dvz;
SF[17] = dvx - dvxNoise; SF[17] = dvx;
SF[18] = dvy - dvyNoise; SF[18] = dvy;
SF[19] = sq(q2); SF[19] = sq(q2);
SF[20] = SF[19] - sq(q0) + sq(q1) - sq(q3); SF[20] = SF[19] - sq(q0) + sq(q1) - sq(q3);
SF[21] = SF[19] + sq(q0) - sq(q1) - sq(q3); SF[21] = SF[19] + sq(q0) - sq(q1) - sq(q3);