void Ekf::controlExternalVisionFusion()
{
// Check for new exernal vision data
if (_ev_data_ready) {
// external vision position aiding selection logic
if ((_params.fusion_mode & MASK_USE_EVPOS) && !_control_status.flags.ev_pos && _control_status.flags.tilt_align && _control_status.flags.yaw_align) {
// check for a exernal vision measurement that has fallen behind the fusion time horizon
if (_time_last_imu - _time_last_ext_vision < 2 * EV_MAX_INTERVAL) {
// turn on use of external vision measurements for position and height
_control_status.flags.ev_pos = true;
ECL_INFO("EKF switching to external vision position fusion");
// turn off other forms of height aiding
_control_status.flags.baro_hgt = false;
_control_status.flags.gps_hgt = false;
_control_status.flags.rng_hgt = false;
// reset the position, height and velocity
resetPosition();
resetVelocity();
resetHeight();
}
}
// external vision yaw aiding selection logic
if ((_params.fusion_mode & MASK_USE_EVYAW) && !_control_status.flags.ev_yaw && _control_status.flags.tilt_align) {
// check for a exernal vision measurement that has fallen behind the fusion time horizon
if (_time_last_imu - _time_last_ext_vision < 2 * EV_MAX_INTERVAL) {
// reset the yaw angle to the value from the observaton quaternion
// get the roll, pitch, yaw estimates from the quaternion states
matrix::Quaternion<float> q_init(_state.quat_nominal(0), _state.quat_nominal(1), _state.quat_nominal(2),
_state.quat_nominal(3));
matrix::Euler<float> euler_init(q_init);
// get initial yaw from the observation quaternion
extVisionSample ev_newest = _ext_vision_buffer.get_newest();
matrix::Quaternion<float> q_obs(ev_newest.quat(0), ev_newest.quat(1), ev_newest.quat(2), ev_newest.quat(3));
matrix::Euler<float> euler_obs(q_obs);
euler_init(2) = euler_obs(2);
// save a copy of the quaternion state for later use in calculating the amount of reset change
Quaternion quat_before_reset = _state.quat_nominal;
// calculate initial quaternion states for the ekf
_state.quat_nominal = Quaternion(euler_init);
// calculate the amount that the quaternion has changed by
_state_reset_status.quat_change = _state.quat_nominal * quat_before_reset.inversed();
// add the reset amount to the output observer buffered data
outputSample output_states;
unsigned output_length = _output_buffer.get_length();
for (unsigned i=0; i < output_length; i++) {
output_states = _output_buffer.get_from_index(i);
output_states.quat_nominal *= _state_reset_status.quat_change;
_output_buffer.push_to_index(i,output_states);
}
// capture the reset event
_state_reset_status.quat_counter++;
// flag the yaw as aligned
_control_status.flags.yaw_align = true;
// turn on fusion of external vision yaw measurements and disable all magnetoemter fusion
_control_status.flags.ev_yaw = true;
_control_status.flags.mag_hdg = false;
_control_status.flags.mag_3D = false;
_control_status.flags.mag_dec = false;
ECL_INFO("EKF switching to external vision yaw fusion");
}
}
// determine if we should use the height observation
if (_params.vdist_sensor_type == VDIST_SENSOR_EV) {
_control_status.flags.baro_hgt = false;
_control_status.flags.gps_hgt = false;
_control_status.flags.rng_hgt = false;
_control_status.flags.ev_hgt = true;
_fuse_height = true;
}
// determine if we should use the horizontal position observations
if (_control_status.flags.ev_pos) {
_fuse_pos = true;
// correct position and height for offset relative to IMU
Vector3f pos_offset_body = _params.ev_pos_body - _params.imu_pos_body;
Vector3f pos_offset_earth = _R_to_earth * pos_offset_body;
_ev_sample_delayed.posNED(0) -= pos_offset_earth(0);
_ev_sample_delayed.posNED(1) -= pos_offset_earth(1);
_ev_sample_delayed.posNED(2) -= pos_offset_earth(2);
}
// determine if we should use the yaw observation
if (_control_status.flags.ev_yaw) {
fuseHeading();
}
}
}
void Ekf::controlExternalVisionAiding()
{
// external vision position aiding selection logic
if ((_params.fusion_mode & MASK_USE_EVPOS) && !_control_status.flags.ev_pos && _control_status.flags.tilt_align && _control_status.flags.yaw_align) {
// check for a exernal vision measurement that has fallen behind the fusion time horizon
if (_time_last_imu - _time_last_ext_vision < 2 * EV_MAX_INTERVAL) {
// turn on use of external vision measurements for position and height
_control_status.flags.ev_pos = true;
printf("EKF switching to external vision position fusion\n");
// turn off other forms of height aiding
_control_status.flags.baro_hgt = false;
_control_status.flags.gps_hgt = false;
_control_status.flags.rng_hgt = false;
// reset the position, height and velocity
resetPosition();
resetVelocity();
resetHeight();
}
}
// external vision yaw aiding selection logic
if ((_params.fusion_mode & MASK_USE_EVYAW) && !_control_status.flags.ev_yaw && _control_status.flags.tilt_align) {
// check for a exernal vision measurement that has fallen behind the fusion time horizon
if (_time_last_imu - _time_last_ext_vision < 2 * EV_MAX_INTERVAL) {
// reset the yaw angle to the value from the observaton quaternion
// get the roll, pitch, yaw estimates from the quaternion states
matrix::Quaternion<float> q_init(_state.quat_nominal(0), _state.quat_nominal(1), _state.quat_nominal(2),
_state.quat_nominal(3));
matrix::Euler<float> euler_init(q_init);
// get initial yaw from the observation quaternion
extVisionSample ev_newest = _ext_vision_buffer.get_newest();
matrix::Quaternion<float> q_obs(ev_newest.quat(0), ev_newest.quat(1), ev_newest.quat(2), ev_newest.quat(3));
matrix::Euler<float> euler_obs(q_obs);
euler_init(2) = euler_obs(2);
// save a copy of the quaternion state for later use in calculating the amount of reset change
Quaternion quat_before_reset = _state.quat_nominal;
// calculate initial quaternion states for the ekf
_state.quat_nominal = Quaternion(euler_init);
// calculate the amount that the quaternion has changed by
_state_reset_status.quat_change = _state.quat_nominal * quat_before_reset.inversed();
// add the reset amount to the output observer buffered data
outputSample output_states;
unsigned output_length = _output_buffer.get_length();
for (unsigned i=0; i < output_length; i++) {
output_states = _output_buffer.get_from_index(i);
output_states.quat_nominal *= _state_reset_status.quat_change;
_output_buffer.push_to_index(i,output_states);
}
// capture the reset event
_state_reset_status.quat_counter++;
// flag the yaw as aligned
_control_status.flags.yaw_align = true;
// turn on fusion of external vision yaw measurements and disable all magnetoemter fusion
_control_status.flags.ev_yaw = true;
_control_status.flags.mag_hdg = false;
_control_status.flags.mag_3D = false;
_control_status.flags.mag_dec = false;
printf("EKF switching to external vision yaw fusion\n");
}
}
}
