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position_estimator_inav: add buffer for rotation matrix to do accel bias correction properly

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This commit is contained in:
Anton Babushkin 2014-05-30 11:03:06 +02:00
parent ead91f3259
commit fdd5d7b8b8
1 changed files with 45 additions and 16 deletions
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61
src/modules/position_estimator_inav/position_estimator_inav_main.c
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@ -72,7 +72,7 @@
#define MIN_VALID_W 0.00001f
#define PUB_INTERVAL 10000 // limit publish rate to 100 Hz
#define EST_BUF_SIZE 500000 / PUB_INTERVAL // buffer size is 0.5s
#define EST_BUF_SIZE 250000 / PUB_INTERVAL // buffer size is 0.5s
static bool thread_should_exit = false; /**< Deamon exit flag */
static bool thread_running = false; /**< Deamon status flag */
@ -146,7 +146,7 @@ int position_estimator_inav_main(int argc, char *argv[])
thread_should_exit = false;
position_estimator_inav_task = task_spawn_cmd("position_estimator_inav",
SCHED_DEFAULT, SCHED_PRIORITY_MAX - 5, 4000,
SCHED_DEFAULT, SCHED_PRIORITY_MAX - 5, 5000,
position_estimator_inav_thread_main,
(argv) ? (const char **) &argv[2] : (const char **) NULL);
exit(0);
@ -210,9 +210,13 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
float y_est[2] = { 0.0f, 0.0f }; // pos, vel
float z_est[2] = { 0.0f, 0.0f }; // pos, vel
float est_buf[EST_BUF_SIZE][3][2];
float est_buf[EST_BUF_SIZE][3][2]; // estimated position buffer
float R_buf[EST_BUF_SIZE][3][3]; // rotation matrix buffer
float R_gps[3][3]; // rotation matrix for GPS correction moment
memset(est_buf, 0, sizeof(est_buf));
int est_buf_ptr = 0;
memset(R_buf, 0, sizeof(R_buf));
memset(R_gps, 0, sizeof(R_gps));
int buf_ptr = 0;
float eph = 1.0;
float epv = 1.0;
@ -673,7 +677,7 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
}
/* calculate index of estimated values in buffer */
int est_i = est_buf_ptr - 1 - min(EST_BUF_SIZE - 1, max(0, (int)(params.delay_gps * 1000000.0f / PUB_INTERVAL)));
int est_i = buf_ptr - 1 - min(EST_BUF_SIZE - 1, max(0, (int)(params.delay_gps * 1000000.0f / PUB_INTERVAL)));
if (est_i < 0) {
est_i += EST_BUF_SIZE;
}
@ -695,6 +699,9 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
corr_gps[2][1] = 0.0f;
}
/* save rotation matrix at this moment */
memcpy(R_gps, R_buf[est_i], sizeof(R_gps));
eph = fminf(eph, gps.eph_m);
epv = fminf(epv, gps.epv_m);
@ -784,7 +791,7 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
corr_baro += offs_corr;
}
/* accelerometer bias correction */
/* accelerometer bias correction for GPS (use buffered rotation matrix) */
float accel_bias_corr[3] = { 0.0f, 0.0f, 0.0f };
if (use_gps_xy) {
@ -798,6 +805,24 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
accel_bias_corr[2] -= corr_gps[2][0] * w_z_gps_p * w_z_gps_p;
}
/* transform error vector from NED frame to body frame */
for (int i = 0; i < 3; i++) {
float c = 0.0f;
for (int j = 0; j < 3; j++) {
c += R_gps[j][i] * accel_bias_corr[j];
}
if (isfinite(c)) {
acc_bias[i] += c * params.w_acc_bias * dt;
}
}
/* accelerometer bias correction for flow and baro (assume that there is no delay) */
accel_bias_corr[0] = 0.0f;
accel_bias_corr[1] = 0.0f;
accel_bias_corr[2] = 0.0f;
if (use_flow) {
accel_bias_corr[0] -= corr_flow[0] * params.w_xy_flow;
accel_bias_corr[1] -= corr_flow[1] * params.w_xy_flow;
@ -934,16 +959,20 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
if (t > pub_last + PUB_INTERVAL) {
pub_last = t;
/* push current estimate to FIFO buffer */
est_buf[est_buf_ptr][0][0] = x_est[0];
est_buf[est_buf_ptr][0][1] = x_est[1];
est_buf[est_buf_ptr][1][0] = y_est[0];
est_buf[est_buf_ptr][1][1] = y_est[1];
est_buf[est_buf_ptr][2][0] = z_est[0];
est_buf[est_buf_ptr][2][1] = z_est[1];
est_buf_ptr++;
if (est_buf_ptr >= EST_BUF_SIZE) {
est_buf_ptr = 0;
/* push current estimate to buffer */
est_buf[buf_ptr][0][0] = x_est[0];
est_buf[buf_ptr][0][1] = x_est[1];
est_buf[buf_ptr][1][0] = y_est[0];
est_buf[buf_ptr][1][1] = y_est[1];
est_buf[buf_ptr][2][0] = z_est[0];
est_buf[buf_ptr][2][1] = z_est[1];
/* push current rotation matrix to buffer */
memcpy(R_buf[buf_ptr], att.R, sizeof(att.R));
buf_ptr++;
if (buf_ptr >= EST_BUF_SIZE) {
buf_ptr = 0;
}
/* publish local position */