src/main/flight/kalman.h

   1 /*
   2  * This file is part of Cleanflight and Betaflight.
   3  *
   4  * Cleanflight and Betaflight are free software. You can redistribute
   5  * this software and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * Cleanflight and Betaflight are distributed in the hope that they
  11  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #pragma once
  22
  23 #include "sensors/gyro.h"
  24 #include "common/filter.h"
  25
  26 #define MAX_KALMAN_WINDOW_SIZE 512
  27
  28 #define VARIANCE_SCALE 0.67f
  29
  30 typedef struct kalman
  31 {
  32     float q;     //process noise covariance
  33     float r;     //measurement noise covariance
  34     float p;     //estimation error covariance matrix
  35     float k;     //kalman gain
  36     float x;     //state
  37     float lastX; //previous state
  38     float e;
  39     float s;
  40
  41     float axisVar;
  42     uint16_t windex;
  43     float axisWindow[MAX_KALMAN_WINDOW_SIZE];
  44     float varianceWindow[MAX_KALMAN_WINDOW_SIZE];
  45     float axisSumMean;
  46     float axisMean;
  47     float axisSumVar;
  48     float inverseN;
  49     uint16_t w;
  50 } kalman_t;
  51
  52 void gyroKalmanInitialize(void);
  53 float gyroKalmanUpdate(uint8_t axis, float input);
  54 void gyroKalmanSetSetpoint(uint8_t axis, float rate);