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attitude_estimator_ekf: correct acceleration continuously, not only on GPS updates

This commit is contained in:
Anton Babushkin 2013-11-02 18:59:55 +04:00
parent 34276c17ca
commit a770bd5cf3
1 changed files with 16 additions and 10 deletions
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26
src/modules/attitude_estimator_ekf/attitude_estimator_ekf_main.cpp
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@ -224,6 +224,7 @@ const unsigned int loop_interval_alarm = 6500; // loop interval in microseconds
uint64_t last_data = 0; uint64_t last_data = 0;
uint64_t last_measurement = 0; uint64_t last_measurement = 0;
uint64_t last_gps = 0;
float vel_prev[3] = { 0.0f, 0.0f, 0.0f }; float vel_prev[3] = { 0.0f, 0.0f, 0.0f };
@ -363,17 +364,20 @@ const unsigned int loop_interval_alarm = 6500; // loop interval in microseconds
float acc[3]; float acc[3];
if (gps.fix_type >= 3 && gps.eph_m < 10.0f && gps.vel_ned_valid && hrt_absolute_time() < gps.timestamp_velocity + 500000) { if (gps.fix_type >= 3 && gps.eph_m < 10.0f && gps.vel_ned_valid && hrt_absolute_time() < gps.timestamp_velocity + 500000) {
/* calculate acceleration in NED frame */ if (last_gps != 0 && gps.timestamp_velocity != last_gps) {
float acc_NED[3]; float gps_dt = (gps.timestamp_velocity - last_gps) / 1000000.0f;
acc_NED[0] = (gps.vel_n_m_s - vel_prev[0]) / dt; /* calculate acceleration in NED frame */
acc_NED[1] = (gps.vel_e_m_s - vel_prev[1]) / dt; float acc_NED[3];
acc_NED[2] = (gps.vel_d_m_s - vel_prev[2]) / dt; acc_NED[0] = (gps.vel_n_m_s - vel_prev[0]) / gps_dt;
acc_NED[1] = (gps.vel_e_m_s - vel_prev[1]) / gps_dt;
acc_NED[2] = (gps.vel_d_m_s - vel_prev[2]) / gps_dt;
/* project acceleration to body frame */ /* project acceleration to body frame */
for (int i = 0; i < 3; i++) { for (int i = 0; i < 3; i++) {
acc[i] = 0.0f; acc[i] = 0.0f;
for (int j = 0; j < 3; j++) { for (int j = 0; j < 3; j++) {
acc[i] += att.R[j][i] * acc_NED[j]; acc[i] += att.R[j][i] * acc_NED[j];
}
} }
} }
@ -387,10 +391,12 @@ const unsigned int loop_interval_alarm = 6500; // loop interval in microseconds
vel_prev[0] = gps.vel_n_m_s; vel_prev[0] = gps.vel_n_m_s;
vel_prev[1] = gps.vel_e_m_s; vel_prev[1] = gps.vel_e_m_s;
vel_prev[2] = gps.vel_d_m_s; vel_prev[2] = gps.vel_d_m_s;
last_gps = gps.timestamp_velocity;
} else { } else {
vel_prev[0] = 0.0f; vel_prev[0] = 0.0f;
vel_prev[1] = 0.0f; vel_prev[1] = 0.0f;
vel_prev[2] = 0.0f; vel_prev[2] = 0.0f;
last_gps = 0;
} }
z_k[3] = raw.accelerometer_m_s2[0] - acc[0]; z_k[3] = raw.accelerometer_m_s2[0] - acc[0];