mirror of https://github.com/ArduPilot/ardupilot
122 lines
5.2 KiB
C++
122 lines
5.2 KiB
C++
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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#ifndef __AP_INERTIALNAV_H__
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#define __AP_INERTIALNAV_H__
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#include <AP_AHRS.h>
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#include <AP_InertialSensor.h> // ArduPilot Mega IMU Library
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#include <AP_Baro.h> // ArduPilot Mega Barometer Library
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#include <ThirdOrderCompFilter.h> // Complementary filter for combining barometer altitude with accelerometers
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#define AP_INTERTIALNAV_GRAVITY 9.80665
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#define AP_INTERTIALNAV_TC_XY 3.0 // default time constant for complementary filter's X & Y axis
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#define AP_INTERTIALNAV_TC_Z 1.5 // default time constant for complementary filter's Z axis
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/*
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* AP_InertialNav is an attempt to use accelerometers to augment other sensors to improve altitud e position hold
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*/
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class AP_InertialNav
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{
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public:
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// Constructor
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AP_InertialNav( AP_AHRS* ahrs, AP_InertialSensor* ins, AP_Baro* baro, GPS** gps_ptr ) :
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_ahrs(ahrs),
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_ins(ins),
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_baro(baro),
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_gps_ptr(gps_ptr),
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_baro_last_update(0),
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_gps_last_update(0),
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_xy_enabled(false),
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_comp_filter(AP_INTERTIALNAV_TC_XY, AP_INTERTIALNAV_TC_Z)
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{}
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// Initialisation
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virtual void init() {
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set_time_constant_xy(_time_constant_xy);
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set_time_constant_z(_time_constant_z);
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}
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// save_params - save all parameters to eeprom
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virtual void save_params();
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// set time constant - set timeconstant used by complementary filter
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virtual void set_time_constant_xy( float time_constant_in_seconds );
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// set time constant - set timeconstant used by complementary filter
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virtual void set_time_constant_z( float time_constant_in_seconds );
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// check_baro - check if new baro readings have arrived and use them to correct vertical accelerometer offsets
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virtual void check_baro();
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// correct_with_baro - modifies accelerometer offsets using barometer. dt is time since last baro reading
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virtual void correct_with_baro(float baro_alt, float dt);
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// set_current_position - all internal calculations are recorded as the distances from this point
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virtual void set_current_position(int32_t lon, int32_t lat);
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// check_gps - check if new gps readings have arrived and use them to correct position estimates
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virtual void check_gps();
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// correct_with_gps - modifies accelerometer offsets using gps. dt is time since last gps update
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virtual void correct_with_gps(int32_t lon, int32_t lat, float dt);
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// update - updates velocities and positions using latest info from accelerometers;
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virtual void update(float dt);
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// altitude_ok, position_ok - true if inertial based altitude and position can be trusted
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virtual bool altitude_ok() { return true; }
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virtual bool position_ok();
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// get_altitude - get latest altitude estimate in cm
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virtual float get_altitude() { return _position.z; }
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virtual void set_altitude( int32_t new_altitude) { _comp_filter.set_3rd_order_z(new_altitude); }
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// get_velocity_z - get latest climb rate (in cm/s)
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virtual float get_velocity_z() { return _velocity.z; }
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virtual void set_velocity_z( int32_t new_velocity ) { _comp_filter.set_2nd_order_z(new_velocity); }
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// get latitude & longitude positions
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virtual int32_t get_latitude();
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virtual int32_t get_longitude();
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// get latitude & longitude positions from base location
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virtual float get_latitude_diff();
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virtual float get_longitude_diff();
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// get velocity in latitude & longitude directions
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virtual float get_latitude_velocity();
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virtual float get_longitude_velocity();
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// class level parameters
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static const struct AP_Param::GroupInfo var_info[];
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//protected:
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AP_AHRS* _ahrs;
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AP_InertialSensor* _ins;
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AP_Baro* _baro;
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GPS** _gps_ptr;
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uint32_t _baro_last_update;
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uint32_t _gps_last_update; // system time of last gps update
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uint32_t _gps_last_time; // time of last gps update according to the gps itself
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bool _xy_enabled;
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AP_Float _time_constant_xy; // time constant for complementary filter's horizontal corrections
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AP_Float _time_constant_z; // time constant for complementary filter's vertical corrections
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Vector3f _accel_bf; // latest accelerometer values
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Vector3f _accel_ef; // accelerometer values converted from body to earth frame
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AP_Vector3f _accel_correction; // accelerometer corrections calculated by complementary filter
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Vector3f _velocity; // latest velocity estimate (integrated from accelerometer values)
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Vector3f _position; // latest position estimate
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int32_t _base_lat; // base latitude
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int32_t _base_lon; // base longitude
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float _lon_to_m_scaling; // conversion of longitude to meters
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ThirdOrderCompFilter _comp_filter; // 3rd order complementary filter for combining baro readings with accelerometers
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};
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#endif // __AP_INERTIALNAV_H__
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