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/*
* Copyright © 2011 Keith Packard <keithp@keithp.com>
*
* 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 2 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, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#ifndef AO_FLIGHT_TEST
#include "ao.h"
#include "ao_flight.h"
#endif
#include "ao_sample.h"
#include "ao_kalman.h"
static ao_k_t ao_k_height;
static ao_k_t ao_k_speed;
static ao_k_t ao_k_accel;
#define AO_K_STEP_100 to_fix_v(0.01)
#define AO_K_STEP_2_2_100 to_fix_v(0.00005)
#define AO_K_STEP_10 to_fix_v(0.1)
#define AO_K_STEP_2_2_10 to_fix_v(0.005)
#define AO_K_STEP_1 to_fix_v(1)
#define AO_K_STEP_2_2_1 to_fix_v(0.5)
ao_v_t ao_height;
ao_v_t ao_speed;
ao_v_t ao_accel;
ao_v_t ao_max_height;
static ao_k_t ao_avg_height_scaled;
ao_v_t ao_avg_height;
ao_v_t ao_error_h;
#if !HAS_ACCEL || AO_FLIGHT_TEST
#define AO_ERROR_H_SQ_AVG 1
#endif
#if AO_ERROR_H_SQ_AVG
ao_v_t ao_error_h_sq_avg;
#endif
#if HAS_ACCEL
ao_v_t ao_error_a;
#endif
static void
ao_kalman_predict(void)
{
#ifdef AO_FLIGHT_TEST
if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_1 +
(ao_k_t) ao_accel * AO_K_STEP_2_2_1) >> 4;
ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_1;
return;
}
if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_10 +
(ao_k_t) ao_accel * AO_K_STEP_2_2_10) >> 4;
ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_10;
return;
}
if (ao_flight_debug) {
printf ("predict speed %g + (%g * %g) = %g\n",
ao_k_speed / (65536.0 * 16.0), ao_accel / 16.0, AO_K_STEP_100 / 65536.0,
(ao_k_speed + (ao_k_t) ao_accel * AO_K_STEP_100) / (65536.0 * 16.0));
}
#endif
ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_100 +
(ao_k_t) ao_accel * AO_K_STEP_2_2_100) >> 4;
ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_100;
}
static void
ao_kalman_err_height(void)
{
#if AO_ERROR_H_SQ_AVG
ao_v_t e;
#endif
ao_v_t height_distrust;
#if HAS_ACCEL
ao_v_t speed_distrust;
#endif
ao_error_h = ao_sample_height - (ao_v_t) (ao_k_height >> 16);
#if AO_ERROR_H_SQ_AVG
e = ao_error_h;
if (e < 0)
e = -e;
if (e > 127)
e = 127;
ao_error_h_sq_avg -= ao_error_h_sq_avg >> 4;
ao_error_h_sq_avg += (e * e) >> 4;
#endif
if (ao_flight_state >= ao_flight_drogue)
return;
height_distrust = ao_sample_alt - AO_MAX_BARO_HEIGHT;
#if HAS_ACCEL
/* speed is stored * 16, but we need to ramp between 248 and 328, so
* we want to multiply by 2. The result is a shift by 3.
*/
speed_distrust = (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) >> (4 - 1);
if (speed_distrust > AO_MAX_SPEED_DISTRUST)
speed_distrust = AO_MAX_SPEED_DISTRUST;
if (speed_distrust > height_distrust)
height_distrust = speed_distrust;
#endif
if (height_distrust > 0) {
#ifdef AO_FLIGHT_TEST
int old_ao_error_h = ao_error_h;
#endif
if (height_distrust > 0x100)
height_distrust = 0x100;
ao_error_h = (ao_v_t) (((ao_k_t) ao_error_h * (0x100 - height_distrust)) >> 8);
#ifdef AO_FLIGHT_TEST
if (ao_flight_debug) {
printf("over height %g over speed %g distrust: %g height: error %d -> %d\n",
(double) (ao_sample_alt - AO_MAX_BARO_HEIGHT),
(ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) / 16.0,
height_distrust / 256.0,
old_ao_error_h, ao_error_h);
}
#endif
}
}
static void
ao_kalman_correct_baro(void)
{
ao_kalman_err_height();
#ifdef AO_FLIGHT_TEST
if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
ao_k_height += (ao_k_t) AO_BARO_K0_1 * ao_error_h;
ao_k_speed += (ao_k_t) AO_BARO_K1_1 * ao_error_h;
ao_k_accel += (ao_k_t) AO_BARO_K2_1 * ao_error_h;
return;
}
if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
ao_k_height += (ao_k_t) AO_BARO_K0_10 * ao_error_h;
ao_k_speed += (ao_k_t) AO_BARO_K1_10 * ao_error_h;
ao_k_accel += (ao_k_t) AO_BARO_K2_10 * ao_error_h;
return;
}
#endif
ao_k_height += (ao_k_t) AO_BARO_K0_100 * ao_error_h;
ao_k_speed += (ao_k_t) AO_BARO_K1_100 * ao_error_h;
ao_k_accel += (ao_k_t) AO_BARO_K2_100 * ao_error_h;
}
#if HAS_ACCEL
static void
ao_kalman_err_accel(void)
{
ao_k_t accel;
accel = (ao_config.accel_plus_g - ao_sample_accel) * ao_accel_scale;
/* Can't use ao_accel here as it is the pre-prediction value still */
ao_error_a = (accel - ao_k_accel) >> 16;
}
#ifndef FORCE_ACCEL
static void
ao_kalman_correct_both(void)
{
ao_kalman_err_height();
ao_kalman_err_accel();
#ifdef AO_FLIGHT_TEST
if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
if (ao_flight_debug) {
printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
ao_k_speed / (65536.0 * 16.0),
(double) ao_error_h, AO_BOTH_K10_1 / 65536.0,
(double) ao_error_a, AO_BOTH_K11_1 / 65536.0,
(ao_k_speed +
(ao_k_t) AO_BOTH_K10_1 * ao_error_h +
(ao_k_t) AO_BOTH_K11_1 * ao_error_a) / (65536.0 * 16.0));
}
ao_k_height +=
(ao_k_t) AO_BOTH_K00_1 * ao_error_h +
(ao_k_t) AO_BOTH_K01_1 * ao_error_a;
ao_k_speed +=
(ao_k_t) AO_BOTH_K10_1 * ao_error_h +
(ao_k_t) AO_BOTH_K11_1 * ao_error_a;
ao_k_accel +=
(ao_k_t) AO_BOTH_K20_1 * ao_error_h +
(ao_k_t) AO_BOTH_K21_1 * ao_error_a;
return;
}
if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
if (ao_flight_debug) {
printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
ao_k_speed / (65536.0 * 16.0),
(double) ao_error_h, AO_BOTH_K10_10 / 65536.0,
(double) ao_error_a, AO_BOTH_K11_10 / 65536.0,
(ao_k_speed +
(ao_k_t) AO_BOTH_K10_10 * ao_error_h +
(ao_k_t) AO_BOTH_K11_10 * ao_error_a) / (65536.0 * 16.0));
}
ao_k_height +=
(ao_k_t) AO_BOTH_K00_10 * ao_error_h +
(ao_k_t) AO_BOTH_K01_10 * ao_error_a;
ao_k_speed +=
(ao_k_t) AO_BOTH_K10_10 * ao_error_h +
(ao_k_t) AO_BOTH_K11_10 * ao_error_a;
ao_k_accel +=
(ao_k_t) AO_BOTH_K20_10 * ao_error_h +
(ao_k_t) AO_BOTH_K21_10 * ao_error_a;
return;
}
if (ao_flight_debug) {
printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
ao_k_speed / (65536.0 * 16.0),
(double) ao_error_h, AO_BOTH_K10_100 / 65536.0,
(double) ao_error_a, AO_BOTH_K11_100 / 65536.0,
(ao_k_speed +
(ao_k_t) AO_BOTH_K10_100 * ao_error_h +
(ao_k_t) AO_BOTH_K11_100 * ao_error_a) / (65536.0 * 16.0));
}
#endif
ao_k_height +=
(ao_k_t) AO_BOTH_K00_100 * ao_error_h +
(ao_k_t) AO_BOTH_K01_100 * ao_error_a;
ao_k_speed +=
(ao_k_t) AO_BOTH_K10_100 * ao_error_h +
(ao_k_t) AO_BOTH_K11_100 * ao_error_a;
ao_k_accel +=
(ao_k_t) AO_BOTH_K20_100 * ao_error_h +
(ao_k_t) AO_BOTH_K21_100 * ao_error_a;
}
#else
static void
ao_kalman_correct_accel(void)
{
ao_kalman_err_accel();
if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
ao_k_height +=(ao_k_t) AO_ACCEL_K0_10 * ao_error_a;
ao_k_speed += (ao_k_t) AO_ACCEL_K1_10 * ao_error_a;
ao_k_accel += (ao_k_t) AO_ACCEL_K2_10 * ao_error_a;
return;
}
ao_k_height += (ao_k_t) AO_ACCEL_K0_100 * ao_error_a;
ao_k_speed += (ao_k_t) AO_ACCEL_K1_100 * ao_error_a;
ao_k_accel += (ao_k_t) AO_ACCEL_K2_100 * ao_error_a;
}
#endif /* else FORCE_ACCEL */
#endif /* HAS_ACCEL */
void
ao_kalman(void)
{
ao_kalman_predict();
#if HAS_ACCEL
if (ao_flight_state <= ao_flight_coast) {
#ifdef FORCE_ACCEL
ao_kalman_correct_accel();
#else
ao_kalman_correct_both();
#endif
} else
#endif
ao_kalman_correct_baro();
ao_height = from_fix(ao_k_height);
ao_speed = from_fix(ao_k_speed);
ao_accel = from_fix(ao_k_accel);
if (ao_height > ao_max_height)
ao_max_height = ao_height;
ao_avg_height_scaled = ao_avg_height_scaled - ao_avg_height + ao_sample_height;
#ifdef AO_FLIGHT_TEST
if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50)
ao_avg_height = (ao_avg_height_scaled + 1) >> 1;
else if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5)
ao_avg_height = (ao_avg_height_scaled + 7) >> 4;
else
#endif
ao_avg_height = (ao_avg_height_scaled + 63) >> 7;
}
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