void nps_sensor_gyro_run_step(struct NpsSensorGyro* gyro, double time, struct DoubleRMat* body_to_imu) {
if (time < gyro->next_update)
return;
/* transform body rates to IMU frame */
struct DoubleVect3* rate_body = (struct DoubleVect3*)(&fdm.body_inertial_rotvel);
struct DoubleVect3 rate_imu;
MAT33_VECT3_MUL(rate_imu, *body_to_imu, *rate_body );
/* compute gyros readings */
MAT33_VECT3_MUL(gyro->value, gyro->sensitivity, rate_imu);
VECT3_ADD(gyro->value, gyro->neutral);
/* compute gyro error readings */
struct DoubleVect3 gyro_error;
VECT3_COPY(gyro_error, gyro->bias_initial);
double_vect3_add_gaussian_noise(&gyro_error, &gyro->noise_std_dev);
double_vect3_update_random_walk(&gyro->bias_random_walk_value, &gyro->bias_random_walk_std_dev,
NPS_GYRO_DT, 5.);
VECT3_ADD(gyro_error, gyro->bias_random_walk_value);
struct DoubleVect3 gain = {NPS_GYRO_SENSITIVITY_PP, NPS_GYRO_SENSITIVITY_QQ, NPS_GYRO_SENSITIVITY_RR};
VECT3_EW_MUL(gyro_error, gyro_error, gain);
VECT3_ADD(gyro->value, gyro_error);
/* round signal to account for adc discretisation */
DOUBLE_VECT3_ROUND(gyro->value);
/* saturate */
VECT3_BOUND_CUBE(gyro->value, gyro->min, gyro->max);
gyro->next_update += NPS_GYRO_DT;
gyro->data_available = TRUE;
}
void nps_sensor_mag_run_step(struct NpsSensorMag* mag, double time, struct DoubleRMat* body_to_imu) {
if (time < mag->next_update)
return;
/* transform magnetic field to body frame */
struct DoubleVect3 h_body;
double_quat_vmult(&h_body, &fdm.ltp_to_body_quat, &fdm.ltp_h);
/* transform to imu frame */
struct DoubleVect3 h_imu;
MAT33_VECT3_MUL(h_imu, *body_to_imu, h_body );
/* transform to sensor frame */
struct DoubleVect3 h_sensor;
MAT33_VECT3_MUL(h_sensor, mag->imu_to_sensor_rmat, h_imu );
/* compute magnetometer reading */
MAT33_VECT3_MUL(mag->value, mag->sensitivity, h_sensor);
VECT3_ADD(mag->value, mag->neutral);
/* FIXME: ADD error reading */
/* round signal to account for adc discretisation */
DOUBLE_VECT3_ROUND(mag->value);
/* saturate */
VECT3_BOUND_CUBE(mag->value, mag->min, mag->max);
mag->next_update += NPS_MAG_DT;
mag->data_available = TRUE;
}
void nps_sensor_accel_run_step(struct NpsSensorAccel* accel, double time, struct DoubleRMat* body_to_imu) {
if (time < accel->next_update)
return;
/* transform gravity to body frame */
struct DoubleVect3 g_body;
FLOAT_QUAT_VMULT(g_body, fdm.ltp_to_body_quat, fdm.ltp_g);
// printf(" g_body %f %f %f\n", g_body.x, g_body.y, g_body.z);
// printf(" accel_fdm %f %f %f\n", fdm.body_ecef_accel.x, fdm.body_ecef_accel.y, fdm.body_ecef_accel.z);
/* substract gravity to acceleration in body frame */
struct DoubleVect3 accelero_body;
VECT3_DIFF(accelero_body, fdm.body_ecef_accel, g_body);
// printf(" accelero body %f %f %f\n", accelero_body.x, accelero_body.y, accelero_body.z);
/* transform to imu frame */
struct DoubleVect3 accelero_imu;
MAT33_VECT3_MUL(accelero_imu, *body_to_imu, accelero_body );
/* compute accelero readings */
MAT33_VECT3_MUL(accel->value, accel->sensitivity, accelero_imu);
VECT3_ADD(accel->value, accel->neutral);
/* Compute sensor error */
struct DoubleVect3 accelero_error;
/* constant bias */
VECT3_COPY(accelero_error, accel->bias);
/* white noise */
double_vect3_add_gaussian_noise(&accelero_error, &accel->noise_std_dev);
/* scale */
struct DoubleVect3 gain = {NPS_ACCEL_SENSITIVITY_XX, NPS_ACCEL_SENSITIVITY_YY, NPS_ACCEL_SENSITIVITY_ZZ};
VECT3_EW_MUL(accelero_error, accelero_error, gain);
/* add error */
VECT3_ADD(accel->value, accelero_error);
/* round signal to account for adc discretisation */
DOUBLE_VECT3_ROUND(accel->value);
/* saturate */
VECT3_BOUND_CUBE(accel->value, 0, accel->resolution);
accel->next_update += NPS_ACCEL_DT;
accel->data_available = TRUE;
}