/* * Copyright © 2013 Keith Packard * * 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; version 2 of the License. * * 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 #endif #include #define FIX_BITS 16 #define to_fix_v(x) ((int16_t) ((x) * 65536.0 + 0.5)) #define to_fix_k(x) ((int32_t) ((x) * 65536.0 + 0.5)) #define from_fix8(x) ((x) >> 8) #define from_fix(x) ((x) >> 16) #define fix8_to_fix_v(x) ((x) << 8) #define fix16_to_fix8(x) ((x) >> 8) #include /* Basic time step (96ms) */ #define AO_MK_STEP to_fix_v(0.096) /* step ** 2 / 2 */ #define AO_MK_STEP_2_2 to_fix_v(0.004608) uint32_t ao_k_pa; /* 24.8 fixed point */ int32_t ao_k_pa_speed; /* 16.16 fixed point */ int32_t ao_k_pa_accel; /* 16.16 fixed point */ uint32_t ao_pa; /* integer portion */ int16_t ao_pa_speed; /* integer portion */ int16_t ao_pa_accel; /* integer portion */ void ao_microkalman_init(void) { ao_pa = pa; ao_k_pa = pa << 8; } void ao_microkalman_predict(void) { ao_k_pa += fix16_to_fix8((int32_t) ao_pa_speed * AO_MK_STEP + (int32_t) ao_pa_accel * AO_MK_STEP_2_2); ao_k_pa_speed += (int32_t) ao_pa_accel * AO_MK_STEP; } void ao_microkalman_correct(void) { int16_t e; /* Height error in Pa */ e = pa - from_fix8(ao_k_pa); ao_k_pa += fix16_to_fix8((int32_t) e * AO_MK_BARO_K0_10); ao_k_pa_speed += (int32_t) e * AO_MK_BARO_K1_10; ao_k_pa_accel += (int32_t) e * AO_MK_BARO_K2_10; ao_pa = from_fix8(ao_k_pa); ao_pa_speed = from_fix(ao_k_pa_speed); ao_pa_accel = from_fix(ao_k_pa_accel); }