ardupilot/libraries/AP_AHRS/AP_AHRS_DCM.h

171 lines
5.0 KiB
C++

#ifndef __AP_AHRS_DCM_H__
#define __AP_AHRS_DCM_H__
/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* DCM based AHRS (Attitude Heading Reference System) interface for
* ArduPilot
*
*/
class AP_AHRS_DCM : public AP_AHRS
{
public:
// Constructors
AP_AHRS_DCM(AP_InertialSensor &ins, AP_Baro &baro, AP_GPS &gps) :
AP_AHRS(ins, baro, gps),
_last_declination(0),
_mag_earth(1,0)
{
_dcm_matrix.identity();
// these are experimentally derived from the simulator
// with large drift levels
_ki = 0.0087;
_ki_yaw = 0.01;
}
// return the smoothed gyro vector corrected for drift
const Vector3f get_gyro(void) const {
return _omega + _omega_P + _omega_yaw_P;
}
// return rotation matrix representing rotaton from body to earth axes
const Matrix3f &get_dcm_matrix(void) const {
return _body_dcm_matrix;
}
// return the current drift correction integrator value
const Vector3f &get_gyro_drift(void) const {
return _omega_I;
}
// Methods
void update(void);
void reset(bool recover_eulers = false);
// reset the current attitude, used on new IMU calibration
void reset_attitude(const float &roll, const float &pitch, const float &yaw);
// dead-reckoning support
virtual bool get_position(struct Location &loc);
// status reporting
float get_error_rp(void);
float get_error_yaw(void);
// return a wind estimation vector, in m/s
Vector3f wind_estimate(void) {
return _wind;
}
// return an airspeed estimate if available. return true
// if we have an estimate
bool airspeed_estimate(float *airspeed_ret) const;
bool use_compass(void);
void set_home(const Location &loc);
void estimate_wind(void);
private:
float _ki;
float _ki_yaw;
// Methods
void matrix_update(float _G_Dt);
void normalize(void);
void check_matrix(void);
bool renorm(Vector3f const &a, Vector3f &result);
void drift_correction(float deltat);
void drift_correction_yaw(void);
float yaw_error_compass();
void euler_angles(void);
bool have_gps(void) const;
// primary representation of attitude of board used for all inertial calculations
Matrix3f _dcm_matrix;
// primary representation of attitude of flight vehicle body
Matrix3f _body_dcm_matrix;
Vector3f _omega_P; // accel Omega proportional correction
Vector3f _omega_yaw_P; // proportional yaw correction
Vector3f _omega_I; // Omega Integrator correction
Vector3f _omega_I_sum;
float _omega_I_sum_time;
Vector3f _omega; // Corrected Gyro_Vector data
// variables to cope with delaying the GA sum to match GPS lag
Vector3f ra_delayed(uint8_t instance, const Vector3f &ra);
Vector3f _ra_delay_buffer[INS_MAX_INSTANCES];
// P term gain based on spin rate
float _P_gain(float spin_rate);
// P term yaw gain based on rate of change of horiz velocity
float _yaw_gain(void) const;
// state to support status reporting
float _renorm_val_sum;
uint16_t _renorm_val_count;
float _error_rp_sum;
uint16_t _error_rp_count;
float _error_rp_last;
float _error_yaw_sum;
uint16_t _error_yaw_count;
float _error_yaw_last;
// time in millis when we last got a GPS heading
uint32_t _gps_last_update;
// state of accel drift correction
Vector3f _ra_sum[INS_MAX_INSTANCES];
Vector3f _last_velocity;
float _ra_deltat;
uint32_t _ra_sum_start;
// the earths magnetic field
float _last_declination;
Vector2f _mag_earth;
// whether we have GPS lock
bool _have_gps_lock;
// the lat/lng where we last had GPS lock
int32_t _last_lat;
int32_t _last_lng;
// position offset from last GPS lock
float _position_offset_north;
float _position_offset_east;
// whether we have a position estimate
bool _have_position;
// support for wind estimation
Vector3f _last_fuse;
Vector3f _last_vel;
uint32_t _last_wind_time;
float _last_airspeed;
uint32_t _last_consistent_heading;
// estimated wind in m/s
Vector3f _wind;
};
#endif // __AP_AHRS_DCM_H__