void orientationCalcEulers_f(struct OrientationReps* orientation) {
if (bit_is_set(orientation->status, ORREP_EULER_F))
return;
if (bit_is_set(orientation->status, ORREP_EULER_I)) {
EULERS_FLOAT_OF_BFP(orientation->eulers_f, orientation->eulers_i);
}
else if (bit_is_set(orientation->status, ORREP_RMAT_F)) {
FLOAT_EULERS_OF_RMAT(orientation->eulers_f, orientation->rmat_f);
}
else if (bit_is_set(orientation->status, ORREP_QUAT_F)) {
FLOAT_EULERS_OF_QUAT(orientation->eulers_f, orientation->quat_f);
}
else if (bit_is_set(orientation->status, ORREP_RMAT_I)) {
RMAT_FLOAT_OF_BFP(orientation->rmat_f, orientation->rmat_i);
SetBit(orientation->status, ORREP_RMAT_F);
FLOAT_EULERS_OF_RMAT(orientation->eulers_f, orientation->rmat_f);
}
else if (bit_is_set(orientation->status, ORREP_QUAT_I)) {
QUAT_FLOAT_OF_BFP(orientation->quat_f, orientation->quat_i);
SetBit(orientation->status, ORREP_QUAT_F);
FLOAT_EULERS_OF_QUAT(orientation->eulers_f, orientation->quat_f);
}
/* set bit to indicate this representation is computed */
SetBit(orientation->status, ORREP_EULER_F);
}
void ahrs_update_mag_2d_dumb(void) {
/* project mag on local tangeant plane */
struct FloatEulers ltp_to_imu_euler;
FLOAT_EULERS_OF_RMAT(ltp_to_imu_euler, ahrs_impl.ltp_to_imu_rmat);
struct FloatVect3 magf;
MAGS_FLOAT_OF_BFP(magf, imu.mag);
const float cphi = cosf(ltp_to_imu_euler.phi);
const float sphi = sinf(ltp_to_imu_euler.phi);
const float ctheta = cosf(ltp_to_imu_euler.theta);
const float stheta = sinf(ltp_to_imu_euler.theta);
const float mn = ctheta * magf.x + sphi*stheta*magf.y + cphi*stheta*magf.z;
const float me = 0. * magf.x + cphi *magf.y - sphi *magf.z;
const float res_norm = -RMAT_ELMT(ahrs_impl.ltp_to_imu_rmat, 0,0) * me +
RMAT_ELMT(ahrs_impl.ltp_to_imu_rmat, 1,0) * mn;
const struct FloatVect3 r2 = {RMAT_ELMT(ahrs_impl.ltp_to_imu_rmat, 2,0),
RMAT_ELMT(ahrs_impl.ltp_to_imu_rmat, 2,1),
RMAT_ELMT(ahrs_impl.ltp_to_imu_rmat, 2,2)};
const float mag_rate_update_gain = 2.5;
FLOAT_RATES_ADD_SCALED_VECT(ahrs_impl.rate_correction, r2, (mag_rate_update_gain*res_norm));
const float mag_bias_update_gain = -2.5e-4;
FLOAT_RATES_ADD_SCALED_VECT(ahrs_impl.gyro_bias, r2, (mag_bias_update_gain*res_norm));
}
/*
* Compute body orientation and rates from imu orientation and rates
*/
static inline void compute_body_orientation_and_rates(void) {
FLOAT_QUAT_COMP_INV(ahrs_float.ltp_to_body_quat,
ahrs_float.ltp_to_imu_quat, ahrs_impl.body_to_imu_quat);
FLOAT_RMAT_COMP_INV(ahrs_float.ltp_to_body_rmat,
ahrs_float.ltp_to_imu_rmat, ahrs_impl.body_to_imu_rmat);
FLOAT_EULERS_OF_RMAT(ahrs_float.ltp_to_body_euler, ahrs_float.ltp_to_body_rmat);
FLOAT_RMAT_TRANSP_RATEMULT(ahrs_float.body_rate, ahrs_impl.body_to_imu_rmat, ahrs_float.imu_rate);
}
/*
* Compute body orientation and rates from imu orientation and rates
*/
static inline void set_body_orientation_and_rates(void) {
struct FloatRates body_rate;
FLOAT_RMAT_TRANSP_RATEMULT(body_rate, ahrs_impl.body_to_imu_rmat, ahrs_impl.imu_rate);
stateSetBodyRates_f(&body_rate);
struct FloatRMat ltp_to_imu_rmat, ltp_to_body_rmat;
FLOAT_RMAT_OF_EULERS(ltp_to_imu_rmat, ahrs_impl.ltp_to_imu_euler);
FLOAT_RMAT_COMP_INV(ltp_to_body_rmat, ltp_to_imu_rmat, ahrs_impl.body_to_imu_rmat);
// Some stupid lines of code for neutrals
struct FloatEulers ltp_to_body_euler;
FLOAT_EULERS_OF_RMAT(ltp_to_body_euler, ltp_to_body_rmat);
ltp_to_body_euler.phi -= ins_roll_neutral;
ltp_to_body_euler.theta -= ins_pitch_neutral;
stateSetNedToBodyEulers_f(<p_to_body_euler);
// should be replaced at the end by:
// stateSetNedToBodyRMat_f(<p_to_body_rmat);
}
float test_quat_of_rmat(void) {
// struct FloatEulers eul = {-0.280849, 0.613423, -1.850440};
struct FloatEulers eul = {RadOfDeg(0.131579), RadOfDeg(-62.397659), RadOfDeg(-110.470299)};
// struct FloatEulers eul = {RadOfDeg(0.13), RadOfDeg(180.), RadOfDeg(-61.)};
struct FloatMat33 rm;
FLOAT_RMAT_OF_EULERS(rm, eul);
DISPLAY_FLOAT_RMAT_AS_EULERS_DEG("rmat", rm);
struct FloatQuat q;
FLOAT_QUAT_OF_RMAT(q, rm);
DISPLAY_FLOAT_QUAT("q_of_rm ", q);
DISPLAY_FLOAT_QUAT_AS_EULERS_DEG("q_of_rm ", q);
struct FloatQuat qref;
FLOAT_QUAT_OF_EULERS(qref, eul);
DISPLAY_FLOAT_QUAT("q_of_euler", qref);
DISPLAY_FLOAT_QUAT_AS_EULERS_DEG("q_of_euler", qref);
printf("\n\n\n");
struct FloatMat33 r_att;
struct FloatEulers e312 = { eul.phi, eul.theta, eul.psi };
FLOAT_RMAT_OF_EULERS_312(r_att, e312);
DISPLAY_FLOAT_RMAT("r_att ", r_att);
DISPLAY_FLOAT_RMAT_AS_EULERS_DEG("r_att ", r_att);
struct FloatQuat q_att;
FLOAT_QUAT_OF_RMAT(q_att, r_att);
struct FloatEulers e_att;
FLOAT_EULERS_OF_RMAT(e_att, r_att);
DISPLAY_FLOAT_EULERS_DEG("of rmat", e_att);
FLOAT_EULERS_OF_QUAT(e_att, q_att);
DISPLAY_FLOAT_EULERS_DEG("of quat", e_att);
return 0.;
}
float test_eulers_of_rmat(struct FloatRMat frm, int display) {
struct FloatEulers fe;
FLOAT_EULERS_OF_RMAT(fe, frm);
struct Int32RMat irm;
RMAT_BFP_OF_REAL(irm, frm);
struct Int32Eulers ie;
INT32_EULERS_OF_RMAT(ie, irm);
struct FloatEulers fe2;
EULERS_FLOAT_OF_BFP(fe2, ie);
EULERS_SUB(fe2, ie);
float norm_err = FLOAT_EULERS_NORM(fe2);
if (display) {
printf("euler of rmat\n");
// DISPLAY_FLOAT_RMAT("fr", fr);
DISPLAY_FLOAT_EULERS_DEG("fe", fe);
DISPLAY_INT32_EULERS("ie", ie);
DISPLAY_INT32_EULERS_AS_FLOAT_DEG("ieaf", ie);
}
return norm_err;
}
static void ahrs_do_update_mag(void) {
int i, j, k;
#ifdef BAFL_DEBUG2
printf("Mag update.\n");
#endif
MAGS_FLOAT_OF_BFP(bafl_mag, imu.mag);
/* P_prio = P */
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < BAFL_SSIZE; j++) {
bafl_Pprio[i][j] = bafl_P[i][j];
}
}
/*
* set up measurement matrix
*
* h = [236.; -2.; 396.];
* hx = [ h(2); -h(1); 0]; //only psi (phi and theta = 0)
* Hm = Cnb * hx;
* H = [ 0 0 0 0 0
* 0 0 Cnb*hx 0 0 0
* 0 0 0 0 0 ];
* */
/*bafl_H[0][2] = RMAT_ELMT(bafl_dcm, 0, 0) * bafl_h.y - RMAT_ELMT(bafl_dcm, 0, 1) * bafl_h.x;
bafl_H[1][2] = RMAT_ELMT(bafl_dcm, 1, 0) * bafl_h.y - RMAT_ELMT(bafl_dcm, 1, 1) * bafl_h.x;
bafl_H[2][2] = RMAT_ELMT(bafl_dcm, 2, 0) * bafl_h.y - RMAT_ELMT(bafl_dcm, 2, 1) * bafl_h.x;*/
bafl_H[0][2] = -RMAT_ELMT(bafl_dcm, 0, 1);
bafl_H[1][2] = -RMAT_ELMT(bafl_dcm, 1, 1);
bafl_H[2][2] = -RMAT_ELMT(bafl_dcm, 2, 1);
//rest is zero
/**********************************************
* compute Kalman gain K
*
* K = P_prio * H_T * inv(S)
* S = H * P_prio * HT + R
*
* K = P_prio * HT * inv(H * P_prio * HT + R)
*
**********************************************/
/* covariance residual S = H * P_prio * HT + R */
/* temp_S(3x6) = H(3x6) * P_prio(6x6)
*
* only third column of H is non-zero
*/
for (i = 0; i < 3; i++) {
for (j = 0; j < BAFL_SSIZE; j++) {
bafl_tempS[i][j] = bafl_H[i][2] * bafl_Pprio[2][j];
}
}
/* S(3x3) = temp_S(3x6) * HT(6x3) + R(3x3)
*
* only third row of HT is non-zero
*/
for (i = 0; i < 3; i++) {
for (j = 0; j < 3; j++) {
bafl_S[i][j] = bafl_tempS[i][2] * bafl_H[j][2]; /* H[j][2] = HT[2][j] */
}
bafl_S[i][i] += bafl_R_mag;
}
/* invert S
*/
FLOAT_MAT33_INVERT(bafl_invS, bafl_S);
/* temp_K(6x3) = P_prio(6x6) * HT(6x3)
*
* only third row of HT is non-zero
*/
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < 3; j++) {
/* not computing zero elements */
bafl_tempK[i][j] = bafl_Pprio[i][2] * bafl_H[j][2]; /* H[j][2] = HT[2][j] */
}
}
/* K(6x3) = temp_K(6x3) * invS(3x3)
*/
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < 3; j++) {
bafl_K[i][j] = bafl_tempK[i][0] * bafl_invS[0][j];
bafl_K[i][j] += bafl_tempK[i][1] * bafl_invS[1][j];
bafl_K[i][j] += bafl_tempK[i][2] * bafl_invS[2][j];
}
}
/**********************************************
* Update filter state.
*
* The a priori filter state is zero since the errors are corrected after each update.
*
* X = X_prio + K (y - H * X_prio)
* X = K * y
**********************************************/
/* innovation
* y = Cnb * [hx; hy; hz] - mag
*/
FLOAT_RMAT_VECT3_MUL(bafl_ym, bafl_dcm, bafl_h); //can be optimized
FLOAT_VECT3_SUB(bafl_ym, bafl_mag);
/* X(6) = K(6x3) * y(3)
*/
for (i = 0; i < BAFL_SSIZE; i++) {
bafl_X[i] = bafl_K[i][0] * bafl_ym.x;
bafl_X[i] += bafl_K[i][1] * bafl_ym.y;
bafl_X[i] += bafl_K[i][2] * bafl_ym.z;
}
/**********************************************
* Update the filter covariance.
*
* P = P_prio - K * H * P_prio
* P = ( I - K * H ) * P_prio
*
**********************************************/
/* temp(6x6) = I(6x6) - K(6x3)*H(3x6)
*
* last 3 columns of H are zero
*/
for (i = 0; i < 6; i++) {
for (j = 0; j < 6; j++) {
if (i == j) {
bafl_tempP[i][j] = 1.;
} else {
bafl_tempP[i][j] = 0.;
}
if (j == 2) { /* omit the parts where H is zero */
for (k = 0; k < 3; k++) {
bafl_tempP[i][j] -= bafl_K[i][k] * bafl_H[k][j];
}
}
}
}
/* P(6x6) = temp(6x6) * P_prio(6x6)
*/
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < BAFL_SSIZE; j++) {
bafl_P[i][j] = bafl_tempP[i][0] * bafl_Pprio[0][j];
for (k = 1; k < BAFL_SSIZE; k++) {
bafl_P[i][j] += bafl_tempP[i][k] * bafl_Pprio[k][j];
}
}
}
#ifdef LKF_PRINT_P
printf("Pum=");
for (i = 0; i < 6; i++) {
printf("[");
for (j = 0; j < 6; j++) {
printf("%f\t", bafl_P[i][j]);
}
printf("]\n ");
}
printf("\n");
#endif
/**********************************************
* Correct errors.
*
*
**********************************************/
/* Error quaternion.
*/
QUAT_ASSIGN(bafl_q_m_err, 1.0, bafl_X[0]/2, bafl_X[1]/2, bafl_X[2]/2);
FLOAT_QUAT_INVERT(bafl_q_m_err, bafl_q_m_err);
/* normalize */
float q_sq;
q_sq = bafl_q_m_err.qx * bafl_q_m_err.qx + bafl_q_m_err.qy * bafl_q_m_err.qy + bafl_q_m_err.qz * bafl_q_m_err.qz;
if (q_sq > 1) { /* this should actually never happen */
FLOAT_QUAT_SMUL(bafl_q_m_err, bafl_q_m_err, 1 / sqrtf(1 + q_sq));
printf("mag error quaternion q_sq > 1!!\n");
} else {
bafl_q_m_err.qi = sqrtf(1 - q_sq);
}
/* correct attitude
*/
FLOAT_QUAT_COMP(bafl_qtemp, bafl_q_m_err, bafl_quat);
FLOAT_QUAT_COPY(bafl_quat, bafl_qtemp);
/* correct gyro bias
*/
RATES_ASSIGN(bafl_b_m_err, bafl_X[3], bafl_X[4], bafl_X[5]);
RATES_SUB(bafl_bias, bafl_b_m_err);
/*
* compute all representations
*/
/* maintain rotation matrix representation */
FLOAT_RMAT_OF_QUAT(bafl_dcm, bafl_quat);
/* maintain euler representation */
FLOAT_EULERS_OF_RMAT(bafl_eulers, bafl_dcm);
AHRS_TO_BFP();
AHRS_LTP_TO_BODY();
}
static void ahrs_do_update_accel(void) {
int i, j, k;
#ifdef BAFL_DEBUG2
printf("Accel update.\n");
#endif
/* P_prio = P */
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < BAFL_SSIZE; j++) {
bafl_Pprio[i][j] = bafl_P[i][j];
}
}
/*
* set up measurement matrix
*
* g = 9.81
* gx = [ 0 -g 0
* g 0 0
* 0 0 0 ]
* H = [ 0 0 0 ]
* [ -Cnb*gx 0 0 0 ]
* [ 0 0 0 ]
*
* */
bafl_H[0][0] = -RMAT_ELMT(bafl_dcm, 0, 1) * BAFL_g;
bafl_H[0][1] = RMAT_ELMT(bafl_dcm, 0, 0) * BAFL_g;
bafl_H[1][0] = -RMAT_ELMT(bafl_dcm, 1, 1) * BAFL_g;
bafl_H[1][1] = RMAT_ELMT(bafl_dcm, 1, 0) * BAFL_g;
bafl_H[2][0] = -RMAT_ELMT(bafl_dcm, 2, 1) * BAFL_g;
bafl_H[2][1] = RMAT_ELMT(bafl_dcm, 2, 0) * BAFL_g;
/* rest is zero
bafl_H[0][2] = 0.;
bafl_H[1][2] = 0.;
bafl_H[2][2] = 0.;*/
/**********************************************
* compute Kalman gain K
*
* K = P_prio * H_T * inv(S)
* S = H * P_prio * HT + R
*
* K = P_prio * HT * inv(H * P_prio * HT + R)
*
**********************************************/
/* covariance residual S = H * P_prio * HT + R */
/* temp_S(3x6) = H(3x6) * P_prio(6x6)
* last 4 columns of H are zero
*/
for (i = 0; i < 3; i++) {
for (j = 0; j < BAFL_SSIZE; j++) {
bafl_tempS[i][j] = bafl_H[i][0] * bafl_Pprio[0][j];
bafl_tempS[i][j] += bafl_H[i][1] * bafl_Pprio[1][j];
}
}
/* S(3x3) = temp_S(3x6) * HT(6x3) + R(3x3)
*
* bottom 4 rows of HT are zero
*/
for (i = 0; i < 3; i++) {
for (j = 0; j < 3; j++) {
bafl_S[i][j] = bafl_tempS[i][0] * bafl_H[j][0]; /* H[j][0] = HT[0][j] */
bafl_S[i][j] += bafl_tempS[i][1] * bafl_H[j][1]; /* H[j][0] = HT[0][j] */
}
bafl_S[i][i] += bafl_R_accel;
}
/* invert S
*/
FLOAT_MAT33_INVERT(bafl_invS, bafl_S);
/* temp_K(6x3) = P_prio(6x6) * HT(6x3)
*
* bottom 4 rows of HT are zero
*/
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < 3; j++) {
/* not computing zero elements */
bafl_tempK[i][j] = bafl_Pprio[i][0] * bafl_H[j][0]; /* H[j][0] = HT[0][j] */
bafl_tempK[i][j] += bafl_Pprio[i][1] * bafl_H[j][1]; /* H[j][1] = HT[1][j] */
}
}
/* K(6x3) = temp_K(6x3) * invS(3x3)
*/
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < 3; j++) {
bafl_K[i][j] = bafl_tempK[i][0] * bafl_invS[0][j];
bafl_K[i][j] += bafl_tempK[i][1] * bafl_invS[1][j];
bafl_K[i][j] += bafl_tempK[i][2] * bafl_invS[2][j];
}
}
/**********************************************
* Update filter state.
*
* The a priori filter state is zero since the errors are corrected after each update.
*
* X = X_prio + K (y - H * X_prio)
* X = K * y
**********************************************/
/*printf("R = ");
for (i = 0; i < 3; i++) {
printf("[");
for (j = 0; j < 3; j++) {
printf("%f\t", RMAT_ELMT(bafl_dcm, i, j));
}
printf("]\n ");
}
printf("\n");*/
/* innovation
* y = Cnb * -[0; 0; g] - accel
*/
bafl_ya.x = -RMAT_ELMT(bafl_dcm, 0, 2) * BAFL_g - bafl_accel_measure.x;
bafl_ya.y = -RMAT_ELMT(bafl_dcm, 1, 2) * BAFL_g - bafl_accel_measure.y;
bafl_ya.z = -RMAT_ELMT(bafl_dcm, 2, 2) * BAFL_g - bafl_accel_measure.z;
/* X(6) = K(6x3) * y(3)
*/
for (i = 0; i < BAFL_SSIZE; i++) {
bafl_X[i] = bafl_K[i][0] * bafl_ya.x;
bafl_X[i] += bafl_K[i][1] * bafl_ya.y;
bafl_X[i] += bafl_K[i][2] * bafl_ya.z;
}
/**********************************************
* Update the filter covariance.
*
* P = P_prio - K * H * P_prio
* P = ( I - K * H ) * P_prio
*
**********************************************/
/* temp(6x6) = I(6x6) - K(6x3)*H(3x6)
*
* last 4 columns of H are zero
*/
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < BAFL_SSIZE; j++) {
if (i == j) {
bafl_tempP[i][j] = 1.;
} else {
bafl_tempP[i][j] = 0.;
}
if (j < 2) { /* omit the parts where H is zero */
for (k = 0; k < 3; k++) {
bafl_tempP[i][j] -= bafl_K[i][k] * bafl_H[k][j];
}
}
}
}
/* P(6x6) = temp(6x6) * P_prio(6x6)
*/
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < BAFL_SSIZE; j++) {
bafl_P[i][j] = bafl_tempP[i][0] * bafl_Pprio[0][j];
for (k = 1; k < BAFL_SSIZE; k++) {
bafl_P[i][j] += bafl_tempP[i][k] * bafl_Pprio[k][j];
}
}
}
#ifdef LKF_PRINT_P
printf("Pua=");
for (i = 0; i < 6; i++) {
printf("[");
for (j = 0; j < 6; j++) {
printf("%f\t", bafl_P[i][j]);
}
printf("]\n ");
}
printf("\n");
#endif
/**********************************************
* Correct errors.
*
*
**********************************************/
/* Error quaternion.
*/
QUAT_ASSIGN(bafl_q_a_err, 1.0, bafl_X[0]/2, bafl_X[1]/2, bafl_X[2]/2);
FLOAT_QUAT_INVERT(bafl_q_a_err, bafl_q_a_err);
/* normalize
* Is this needed? Or is the approximation good enough?*/
float q_sq;
q_sq = bafl_q_a_err.qx * bafl_q_a_err.qx + bafl_q_a_err.qy * bafl_q_a_err.qy + bafl_q_a_err.qz * bafl_q_a_err.qz;
if (q_sq > 1) { /* this should actually never happen */
FLOAT_QUAT_SMUL(bafl_q_a_err, bafl_q_a_err, 1 / sqrtf(1 + q_sq));
printf("Accel error quaternion q_sq > 1!!\n");
} else {
bafl_q_a_err.qi = sqrtf(1 - q_sq);
}
/* correct attitude
*/
FLOAT_QUAT_COMP(bafl_qtemp, bafl_q_a_err, bafl_quat);
FLOAT_QUAT_COPY(bafl_quat, bafl_qtemp);
/* correct gyro bias
*/
RATES_ASSIGN(bafl_b_a_err, bafl_X[3], bafl_X[4], bafl_X[5]);
RATES_SUB(bafl_bias, bafl_b_a_err);
/*
* compute all representations
*/
/* maintain rotation matrix representation */
FLOAT_RMAT_OF_QUAT(bafl_dcm, bafl_quat);
/* maintain euler representation */
FLOAT_EULERS_OF_RMAT(bafl_eulers, bafl_dcm);
AHRS_TO_BFP();
AHRS_LTP_TO_BODY();
}
/*
* Propagate our dynamic system in time
*
* Run the strapdown computation and the predict step of the filter
*
*
* quat_dot = Wxq(pqr) * quat
* bias_dot = 0
*
* Wxq is the quaternion omega matrix:
*
* [ 0, -p, -q, -r ]
* 1/2 * [ p, 0, r, -q ]
* [ q, -r, 0, p ]
* [ r, q, -p, 0 ]
*
*/
void ahrs_propagate(void) {
int i, j, k;
ahrs_lowpass_accel();
/* compute unbiased rates */
RATES_FLOAT_OF_BFP(bafl_rates, imu.gyro);
RATES_SUB(bafl_rates, bafl_bias);
/* run strapdown computation
*
*/
/* multiplicative quaternion update */
/* compute correction quaternion */
QUAT_ASSIGN(bafl_qr, 1., bafl_rates.p * BAFL_DT / 2, bafl_rates.q * BAFL_DT / 2, bafl_rates.r * BAFL_DT / 2);
/* normalize it. maybe not necessary?? */
float q_sq;
q_sq = (bafl_qr.qx * bafl_qr.qx +bafl_qr.qy * bafl_qr.qy + bafl_qr.qz * bafl_qr.qz) / 4;
if (q_sq > 1) { /* this should actually never happen */
FLOAT_QUAT_SMUL(bafl_qr, bafl_qr, 1 / sqrtf(1 + q_sq));
} else {
bafl_qr.qi = sqrtf(1 - q_sq);
}
/* propagate correction quaternion */
FLOAT_QUAT_COMP(bafl_qtemp, bafl_quat, bafl_qr);
FLOAT_QUAT_COPY(bafl_quat, bafl_qtemp);
bafl_qnorm = FLOAT_QUAT_NORM(bafl_quat);
//TODO check if broot force normalization is good, use lagrange normalization?
FLOAT_QUAT_NORMALISE(bafl_quat);
/*
* compute all representations
*/
/* maintain rotation matrix representation */
FLOAT_RMAT_OF_QUAT(bafl_dcm, bafl_quat);
/* maintain euler representation */
FLOAT_EULERS_OF_RMAT(bafl_eulers, bafl_dcm);
AHRS_TO_BFP();
AHRS_LTP_TO_BODY();
/* error KF-Filter
* propagate only the error covariance matrix since error is corrected after each measurement
*
* F = [ 0 0 0 ]
* [ 0 0 0 -Cbn ]
* [ 0 0 0 ]
* [ 0 0 0 0 0 0 ]
* [ 0 0 0 0 0 0 ]
* [ 0 0 0 0 0 0 ]
*
* T = e^(dt * F)
*
* T = [ 1 0 0 ]
* [ 0 1 0 -Cbn*dt ]
* [ 0 0 1 ]
* [ 0 0 0 1 0 0 ]
* [ 0 0 0 0 1 0 ]
* [ 0 0 0 0 0 1 ]
*
* P_prio = T * P * T_T + Q
*
*/
/*
* compute state transition matrix T
*
* diagonal elements of T are always one
*/
for (i = 0; i < 3; i++) {
for (j = 0; j < 3; j++) {
bafl_T[i][j + 3] = -RMAT_ELMT(bafl_dcm, j, i); /* inverted bafl_dcm */
}
}
/*
* estimate the a priori error covariance matrix P_k = T * P_k-1 * T_T + Q
*/
/* Temporary multiplication temp(6x6) = T(6x6) * P(6x6) */
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < BAFL_SSIZE; j++) {
bafl_tempP[i][j] = 0.;
for (k = 0; k < BAFL_SSIZE; k++) {
bafl_tempP[i][j] += bafl_T[i][k] * bafl_P[k][j];
}
}
}
/* P_k(6x6) = temp(6x6) * T_T(6x6) + Q */
for (i = 0; i < BAFL_SSIZE; i++) {
for (j = 0; j < BAFL_SSIZE; j++) {
bafl_P[i][j] = 0.;
for (k = 0; k < BAFL_SSIZE; k++) {
bafl_P[i][j] += bafl_tempP[i][k] * bafl_T[j][k]; //T[j][k] = T_T[k][j]
}
}
if (i<3) {
bafl_P[i][i] += bafl_Q_att;
} else {
bafl_P[i][i] += bafl_Q_gyro;
}
}
#ifdef LKF_PRINT_P
printf("Pp =");
for (i = 0; i < 6; i++) {
printf("[");
for (j = 0; j < 6; j++) {
printf("%f\t", bafl_P[i][j]);
}
printf("]\n ");
}
printf("\n");
#endif
}
static inline void compute_imu_rmat_and_euler_from_quat(void) {
FLOAT_RMAT_OF_QUAT(ahrs_float.ltp_to_imu_rmat, ahrs_float.ltp_to_imu_quat);
FLOAT_EULERS_OF_RMAT(ahrs_float.ltp_to_imu_euler, ahrs_float.ltp_to_imu_rmat);
}
