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-rw-r--r--src/modules/position_estimator_inav/position_estimator_inav_main.c83
-rw-r--r--src/modules/position_estimator_inav/position_estimator_inav_params.c3
-rw-r--r--src/modules/position_estimator_inav/position_estimator_inav_params.h2
3 files changed, 78 insertions, 10 deletions
diff --git a/src/modules/position_estimator_inav/position_estimator_inav_main.c b/src/modules/position_estimator_inav/position_estimator_inav_main.c
index d7503e42d..aa533c777 100644
--- a/src/modules/position_estimator_inav/position_estimator_inav_main.c
+++ b/src/modules/position_estimator_inav/position_estimator_inav_main.c
@@ -71,6 +71,8 @@
#include "inertial_filter.h"
#define MIN_VALID_W 0.00001f
+#define PUB_INTERVAL 10000 // limit publish rate to 100 Hz
+#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 */
@@ -83,7 +85,6 @@ static const hrt_abstime sonar_timeout = 150000; // sonar timeout = 150ms
static const hrt_abstime sonar_valid_timeout = 1000000; // estimate sonar distance during this time after sonar loss
static const hrt_abstime xy_src_timeout = 2000000; // estimate position during this time after position sources loss
static const uint32_t updates_counter_len = 1000000;
-static const uint32_t pub_interval = 10000; // limit publish rate to 100 Hz
static const float max_flow = 1.0f; // max flow value that can be used, rad/s
__EXPORT int position_estimator_inav_main(int argc, char *argv[]);
@@ -92,6 +93,16 @@ int position_estimator_inav_thread_main(int argc, char *argv[]);
static void usage(const char *reason);
+static inline int min(int val1, int val2)
+{
+ return (val1 < val2) ? val1 : val2;
+}
+
+static inline int max(int val1, int val2)
+{
+ return (val1 > val2) ? val1 : val2;
+}
+
/**
* Print the correct usage.
*/
@@ -135,7 +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);
@@ -199,6 +210,14 @@ 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]; // 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));
+ 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;
@@ -657,16 +676,22 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
y_est[1] = gps.vel_e_m_s;
}
+ /* calculate index of estimated values in buffer */
+ 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;
+ }
+
/* calculate correction for position */
- corr_gps[0][0] = gps_proj[0] - x_est[0];
- corr_gps[1][0] = gps_proj[1] - y_est[0];
- corr_gps[2][0] = local_pos.ref_alt - alt - z_est[0];
+ corr_gps[0][0] = gps_proj[0] - est_buf[est_i][0][0];
+ corr_gps[1][0] = gps_proj[1] - est_buf[est_i][1][0];
+ corr_gps[2][0] = local_pos.ref_alt - alt - est_buf[est_i][2][0];
/* calculate correction for velocity */
if (gps.vel_ned_valid) {
- corr_gps[0][1] = gps.vel_n_m_s - x_est[1];
- corr_gps[1][1] = gps.vel_e_m_s - y_est[1];
- corr_gps[2][1] = gps.vel_d_m_s - z_est[1];
+ corr_gps[0][1] = gps.vel_n_m_s - est_buf[est_i][0][1];
+ corr_gps[1][1] = gps.vel_e_m_s - est_buf[est_i][1][1];
+ corr_gps[2][1] = gps.vel_d_m_s - est_buf[est_i][2][1];
} else {
corr_gps[0][1] = 0.0f;
@@ -674,6 +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);
@@ -763,7 +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) {
@@ -777,6 +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;
@@ -910,8 +956,25 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
}
}
- if (t > pub_last + pub_interval) {
+ if (t > pub_last + PUB_INTERVAL) {
pub_last = t;
+
+ /* 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 */
local_pos.xy_valid = can_estimate_xy;
local_pos.v_xy_valid = can_estimate_xy;
diff --git a/src/modules/position_estimator_inav/position_estimator_inav_params.c b/src/modules/position_estimator_inav/position_estimator_inav_params.c
index 8aa08b6f2..d88419c25 100644
--- a/src/modules/position_estimator_inav/position_estimator_inav_params.c
+++ b/src/modules/position_estimator_inav/position_estimator_inav_params.c
@@ -55,6 +55,7 @@ PARAM_DEFINE_FLOAT(INAV_SONAR_ERR, 0.5f);
PARAM_DEFINE_FLOAT(INAV_LAND_T, 3.0f);
PARAM_DEFINE_FLOAT(INAV_LAND_DISP, 0.7f);
PARAM_DEFINE_FLOAT(INAV_LAND_THR, 0.2f);
+PARAM_DEFINE_FLOAT(INAV_DELAY_GPS, 0.2f);
int parameters_init(struct position_estimator_inav_param_handles *h)
{
@@ -73,6 +74,7 @@ int parameters_init(struct position_estimator_inav_param_handles *h)
h->land_t = param_find("INAV_LAND_T");
h->land_disp = param_find("INAV_LAND_DISP");
h->land_thr = param_find("INAV_LAND_THR");
+ h->delay_gps = param_find("INAV_DELAY_GPS");
return OK;
}
@@ -94,6 +96,7 @@ int parameters_update(const struct position_estimator_inav_param_handles *h, str
param_get(h->land_t, &(p->land_t));
param_get(h->land_disp, &(p->land_disp));
param_get(h->land_thr, &(p->land_thr));
+ param_get(h->delay_gps, &(p->delay_gps));
return OK;
}
diff --git a/src/modules/position_estimator_inav/position_estimator_inav_params.h b/src/modules/position_estimator_inav/position_estimator_inav_params.h
index 08ec996a1..df1cfaa71 100644
--- a/src/modules/position_estimator_inav/position_estimator_inav_params.h
+++ b/src/modules/position_estimator_inav/position_estimator_inav_params.h
@@ -56,6 +56,7 @@ struct position_estimator_inav_params {
float land_t;
float land_disp;
float land_thr;
+ float delay_gps;
};
struct position_estimator_inav_param_handles {
@@ -74,6 +75,7 @@ struct position_estimator_inav_param_handles {
param_t land_t;
param_t land_disp;
param_t land_thr;
+ param_t delay_gps;
};
/**