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EKF: Add position, height and velocity reset for EV aiding

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This commit is contained in:
Paul Riseborough
2016-05-14 21:17:29 +10:00
parent 3a0fcd03d7
commit 81469d6621
5 changed files with 96 additions and 21 deletions
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EKF/ekf_helper.cpp
+68 -19
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@@ -51,15 +51,22 @@
// gps measurement then use for velocity initialisation
bool Ekf::resetVelocity()
{
// if we have a valid GPS measurement use it to initialise velocity states
gpsSample gps_newest = _gps_buffer.get_newest();
if (_control_status.flags.gps) {
// if we have a valid GPS measurement use it to initialise velocity states
gpsSample gps_newest = _gps_buffer.get_newest();
if (_time_last_imu - gps_newest.time_us < 400000) {
_state.vel = gps_newest.vel;
if (_time_last_imu - gps_newest.time_us < 2*GPS_MAX_INTERVAL) {
_state.vel = gps_newest.vel;
return true;
} else {
// XXX use the value of the last known velocity
return false;
}
} else if (_control_status.flags.opt_flow || _control_status.flags.ev_pos) {
_state.vel.setZero();
return true;
} else {
// XXX use the value of the last known velocity
return false;
}
}
@@ -68,18 +75,48 @@ bool Ekf::resetVelocity()
// gps measurement then use for position initialisation
bool Ekf::resetPosition()
{
// if we have a fresh GPS measurement, use it to initialise position states and correct the position for the measurement delay
gpsSample gps_newest = _gps_buffer.get_newest();
if (_control_status.flags.gps) {
// if we have a fresh GPS measurement, use it to initialise position states and correct the position for the measurement delay
gpsSample gps_newest = _gps_buffer.get_newest();
float time_delay = 1e-6f * (float)(_time_last_imu - gps_newest.time_us);
float time_delay = 1e-6f * (float)(_imu_sample_delayed.time_us - gps_newest.time_us);
float max_time_delay = 1e-6f * (float)GPS_MAX_INTERVAL;
if (time_delay < 0.4f) {
_state.pos(0) = gps_newest.pos(0) + gps_newest.vel(0) * time_delay;
_state.pos(1) = gps_newest.pos(1) + gps_newest.vel(1) * time_delay;
if (time_delay < max_time_delay) {
_state.pos(0) = gps_newest.pos(0) + gps_newest.vel(0) * time_delay;
_state.pos(1) = gps_newest.pos(1) + gps_newest.vel(1) * time_delay;
return true;
} else {
// XXX use the value of the last known position
return false;
}
} else if (_control_status.flags.opt_flow) {
_state.pos(0) = 0.0f;
_state.pos(1) = 0.0f;
return true;
} else if (_control_status.flags.ev_pos) {
// if we have fresh data, reset the position to the measurement
extVisionSample ev_newest = _ext_vision_buffer.get_newest();
if (_time_last_imu - ev_newest.time_us < 2*EV_MAX_INTERVAL) {
// use the most recent data if it's time offset from the fusion time horizon is smaller
int32_t dt_newest = ev_newest.time_us - _imu_sample_delayed.time_us;
int32_t dt_delayed = _ev_sample_delayed.time_us - _imu_sample_delayed.time_us;
if (abs(dt_newest) < abs(dt_delayed)) {
_state.pos(0) = ev_newest.posNED(0);
_state.pos(1) = ev_newest.posNED(1);
} else {
_state.pos(0) = _ev_sample_delayed.posNED(0);
_state.pos(1) = _ev_sample_delayed.posNED(1);
}
return true;
} else {
// XXX use the value of the last known position
return false;
}
} else {
// XXX use the value of the last known position
return false;
}
}
@@ -116,13 +153,14 @@ void Ekf::resetHeight()
vert_pos_reset = true;
// reset the baro offset which is subtracted from the baro reading if we need to use it as a backup
baroSample baro_newest = _baro_buffer.get_newest();
_baro_hgt_offset = baro_newest.hgt + _state.pos(2);
} else {
// TODO: reset to last known range based estimate
}
// reset the baro offset which is subtracted from the baro reading if we need to use it as a backup
baroSample baro_newest = _baro_buffer.get_newest();
_baro_hgt_offset = baro_newest.hgt + _state.pos(2);
} else if (_control_status.flags.baro_hgt) {
// initialize vertical position with newest baro measurement
@@ -158,13 +196,24 @@ void Ekf::resetHeight()
vert_pos_reset = true;
// reset the baro offset which is subtracted from the baro reading if we need to use it as a backup
baroSample baro_newest = _baro_buffer.get_newest();
_baro_hgt_offset = baro_newest.hgt + _state.pos(2);
} else {
// TODO: reset to last known gps based estimate
}
// reset the baro offset which is subtracted from the baro reading if we need to use it as a backup
baroSample baro_newest = _baro_buffer.get_newest();
_baro_hgt_offset = baro_newest.hgt + _state.pos(2);
} else if (_control_status.flags.ev_pos) {
// initialize vertical position with newest measurement
extVisionSample ev_newest = _ext_vision_buffer.get_newest();
if (_time_last_imu - ev_newest.time_us < 2 * EV_MAX_INTERVAL) {
_state.pos(2) = ev_newest.posNED(2);
} else {
// TODO: reset to last known baro based estimate
}
}
// reset the vertical velocity covariance values