mirror of https://github.com/ArduPilot/ardupilot
128 lines
4.0 KiB
C++
128 lines
4.0 KiB
C++
/*
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smaller EKF for simpler estimation applications
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Converted from Matlab to C++ by Paul Riseborough
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <AP_Math/AP_Math.h>
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#include <AP_Param/AP_Param.h>
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//#include <AP_NavEKF2/AP_NavEKF2.h>
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#include <AP_Math/vectorN.h>
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class SoloGimbalEKF
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{
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public:
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typedef float ftype;
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#if MATH_CHECK_INDEXES
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typedef VectorN<ftype,13> Vector13;
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#else
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typedef ftype Vector13[13];
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#endif
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// Constructor
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SoloGimbalEKF();
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// Run the EKF main loop once every time we receive sensor data
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void RunEKF(float delta_time, const Vector3f &delta_angles, const Vector3f &delta_velocity, const Vector3f &joint_angles);
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void reset();
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// get gyro bias data
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void getGyroBias(Vector3f &gyroBias) const;
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// set gyro bias
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void setGyroBias(const Vector3f &gyroBias);
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// get quaternion data
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void getQuat(Quaternion &quat) const;
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// get filter alignment status - true is aligned
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bool getStatus(void) const;
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static const struct AP_Param::GroupInfo var_info[];
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private:
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// the states are available in two forms, either as a Vector13 or
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// broken down as individual elements. Both are equivalent (same
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// memory)
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Vector13 states;
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struct state_elements {
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Vector3f angErr; // 0..2 rotation vector representing the growth in angle error since the last state correction (rad)
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Vector3f velocity; // 3..5 NED velocity (m/s)
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Vector3f delAngBias; // 6..8 estimated bias errors in the IMU delta angles
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Quaternion quat; // 9..12 these states are used by the INS prediction only and are not used by the EKF state equations.
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} &state;
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// data from sensors
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struct {
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Vector3f delAng;
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Vector3f delVel;
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float gPhi;
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float gPsi;
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float gTheta;
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} gSense;
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float Cov[9][9]; // covariance matrix
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Matrix3f Tsn; // Sensor to NED rotation matrix
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float TiltCorrectionSquared; // Angle correction applied to tilt from last velocity fusion (rad)
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bool newDataMag; // true when new magnetometer data is waiting to be used
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uint32_t StartTime_ms; // time the EKF was started (msec)
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bool FiltInit; // true when EKF is initialised
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bool YawAligned; // true when EKF heading is initialised
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float cosPhi;// = cosf(gSense.gPhi);
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float cosTheta;// = cosf(gSense.gTheta);
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float sinPhi;// = sinf(gSense.gPhi);
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float sinTheta;// = sinf(gSense.gTheta);
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float sinPsi;// = sinf(gSense.gPsi);
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float cosPsi;// = cosf(gSense.gPsi);
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uint32_t lastMagUpdate;
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Vector3f magData;
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uint32_t imuSampleTime_ms;
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float dtIMU;
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// States used for unwrapping of compass yaw error
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float innovationIncrement;
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float lastInnovation;
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// state prediction
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void predictStates();
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// EKF covariance prediction
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void predictCovariance();
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// EKF velocity fusion
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void fuseVelocity();
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// read magnetometer data
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void readMagData();
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// EKF compass fusion
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void fuseCompass();
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// Perform an initial heading alignment using the magnetic field and assumed declination
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void alignHeading();
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// Calculate magnetic heading innovation
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float calcMagHeadingInnov();
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// Force symmmetry and non-negative diagonals on state covarinace matrix
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void fixCovariance();
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};
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