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   1 /*
   2  * Copyright © 2011 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  17  */
  18
  19 #ifndef AO_FLIGHT_TEST
  20 #include "ao.h"
  21 #include "ao_flight.h"
  22 #endif
  23
  24 #include "ao_sample.h"
  25 #include "ao_kalman.h"
  26
  27 static __pdata ao_k_t           ao_k_height;
  28 static __pdata ao_k_t           ao_k_speed;
  29 static __pdata ao_k_t           ao_k_accel;
  30
  31 #define AO_K_STEP_100           to_fix_v(0.01)
  32 #define AO_K_STEP_2_2_100       to_fix_v(0.00005)
  33
  34 #define AO_K_STEP_10            to_fix_v(0.1)
  35 #define AO_K_STEP_2_2_10        to_fix_v(0.005)
  36
  37 #define AO_K_STEP_1             to_fix_v(1)
  38 #define AO_K_STEP_2_2_1         to_fix_v(0.5)
  39
  40 __pdata ao_v_t                  ao_height;
  41 __pdata ao_v_t                  ao_speed;
  42 __pdata ao_v_t                  ao_accel;
  43 __xdata ao_v_t                  ao_max_height;
  44 static __pdata ao_k_t           ao_avg_height_scaled;
  45 __xdata ao_v_t                  ao_avg_height;
  46
  47 __pdata ao_v_t                  ao_error_h;
  48 __pdata ao_v_t                  ao_error_h_sq_avg;
  49
  50 #if HAS_ACCEL
  51 __pdata ao_v_t                  ao_error_a;
  52 #endif
  53
  54 static void
  55 ao_kalman_predict(void)
  56 {
  57 #ifdef AO_FLIGHT_TEST
  58         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
  59                 ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_1 +
  60                                 (ao_k_t) ao_accel * AO_K_STEP_2_2_1) >> 4;
  61                 ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_1;
  62
  63                 return;
  64         }
  65         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
  66                 ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_10 +
  67                                 (ao_k_t) ao_accel * AO_K_STEP_2_2_10) >> 4;
  68                 ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_10;
  69
  70                 return;
  71         }
  72         if (ao_flight_debug) {
  73                 printf ("predict speed %g + (%g * %g) = %g\n",
  74                         ao_k_speed / (65536.0 * 16.0), ao_accel / 16.0, AO_K_STEP_100 / 65536.0,
  75                         (ao_k_speed + (ao_k_t) ao_accel * AO_K_STEP_100) / (65536.0 * 16.0));
  76         }
  77 #endif
  78         ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_100 +
  79                         (ao_k_t) ao_accel * AO_K_STEP_2_2_100) >> 4;
  80         ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_100;
  81 }
  82
  83 static void
  84 ao_kalman_err_height(void)
  85 {
  86         ao_v_t  e;
  87         ao_v_t height_distrust;
  88 #if HAS_ACCEL
  89         ao_v_t  speed_distrust;
  90 #endif
  91
  92         ao_error_h = ao_sample_height - (ao_v_t) (ao_k_height >> 16);
  93
  94         e = ao_error_h;
  95         if (e < 0)
  96                 e = -e;
  97         if (e > 127)
  98                 e = 127;
  99         ao_error_h_sq_avg -= ao_error_h_sq_avg >> 4;
 100         ao_error_h_sq_avg += (e * e) >> 4;
 101
 102         if (ao_flight_state >= ao_flight_drogue)
 103                 return;
 104         height_distrust = ao_sample_alt - AO_MAX_BARO_HEIGHT;
 105 #if HAS_ACCEL
 106         /* speed is stored * 16, but we need to ramp between 200 and 328, so
 107          * we want to multiply by 2. The result is a shift by 3.
 108          */
 109         speed_distrust = (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) >> (4 - 1);
 110         if (speed_distrust <= 0)
 111                 speed_distrust = 0;
 112         else if (speed_distrust > height_distrust)
 113                 height_distrust = speed_distrust;
 114 #endif
 115         if (height_distrust > 0) {
 116 #ifdef AO_FLIGHT_TEST
 117                 int     old_ao_error_h = ao_error_h;
 118 #endif
 119                 if (height_distrust > 0x100)
 120                         height_distrust = 0x100;
 121                 ao_error_h = (ao_v_t) (((ao_k_t) ao_error_h * (0x100 - height_distrust)) >> 8);
 122 #ifdef AO_FLIGHT_TEST
 123                 if (ao_flight_debug) {
 124                         printf("over height %g over speed %g distrust: %g height: error %d -> %d\n",
 125                                (double) (ao_sample_alt - AO_MAX_BARO_HEIGHT),
 126                                (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) / 16.0,
 127                                height_distrust / 256.0,
 128                                old_ao_error_h, ao_error_h);
 129                 }
 130 #endif
 131         }
 132 }
 133
 134 static void
 135 ao_kalman_correct_baro(void)
 136 {
 137         ao_kalman_err_height();
 138 #ifdef AO_FLIGHT_TEST
 139         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
 140                 ao_k_height += (ao_k_t) AO_BARO_K0_1 * ao_error_h;
 141                 ao_k_speed  += (ao_k_t) AO_BARO_K1_1 * ao_error_h;
 142                 ao_k_accel  += (ao_k_t) AO_BARO_K2_1 * ao_error_h;
 143                 return;
 144         }
 145         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
 146                 ao_k_height += (ao_k_t) AO_BARO_K0_10 * ao_error_h;
 147                 ao_k_speed  += (ao_k_t) AO_BARO_K1_10 * ao_error_h;
 148                 ao_k_accel  += (ao_k_t) AO_BARO_K2_10 * ao_error_h;
 149                 return;
 150         }
 151 #endif
 152         ao_k_height += (ao_k_t) AO_BARO_K0_100 * ao_error_h;
 153         ao_k_speed  += (ao_k_t) AO_BARO_K1_100 * ao_error_h;
 154         ao_k_accel  += (ao_k_t) AO_BARO_K2_100 * ao_error_h;
 155 }
 156
 157 #if HAS_ACCEL
 158
 159 static void
 160 ao_kalman_err_accel(void)
 161 {
 162         ao_k_t  accel;
 163
 164         accel = (ao_config.accel_plus_g - ao_sample_accel) * ao_accel_scale;
 165
 166         /* Can't use ao_accel here as it is the pre-prediction value still */
 167         ao_error_a = (accel - ao_k_accel) >> 16;
 168 }
 169
 170 #ifndef FORCE_ACCEL
 171 static void
 172 ao_kalman_correct_both(void)
 173 {
 174         ao_kalman_err_height();
 175         ao_kalman_err_accel();
 176
 177 #ifdef AO_FLIGHT_TEST
 178         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
 179                 if (ao_flight_debug) {
 180                         printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 181                                 ao_k_speed / (65536.0 * 16.0),
 182                                 (double) ao_error_h, AO_BOTH_K10_1 / 65536.0,
 183                                 (double) ao_error_a, AO_BOTH_K11_1 / 65536.0,
 184                                 (ao_k_speed +
 185                                  (ao_k_t) AO_BOTH_K10_1 * ao_error_h +
 186                                  (ao_k_t) AO_BOTH_K11_1 * ao_error_a) / (65536.0 * 16.0));
 187                 }
 188                 ao_k_height +=
 189                         (ao_k_t) AO_BOTH_K00_1 * ao_error_h +
 190                         (ao_k_t) AO_BOTH_K01_1 * ao_error_a;
 191                 ao_k_speed +=
 192                         (ao_k_t) AO_BOTH_K10_1 * ao_error_h +
 193                         (ao_k_t) AO_BOTH_K11_1 * ao_error_a;
 194                 ao_k_accel +=
 195                         (ao_k_t) AO_BOTH_K20_1 * ao_error_h +
 196                         (ao_k_t) AO_BOTH_K21_1 * ao_error_a;
 197                 return;
 198         }
 199         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
 200                 if (ao_flight_debug) {
 201                         printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 202                                 ao_k_speed / (65536.0 * 16.0),
 203                                 (double) ao_error_h, AO_BOTH_K10_10 / 65536.0,
 204                                 (double) ao_error_a, AO_BOTH_K11_10 / 65536.0,
 205                                 (ao_k_speed +
 206                                  (ao_k_t) AO_BOTH_K10_10 * ao_error_h +
 207                                  (ao_k_t) AO_BOTH_K11_10 * ao_error_a) / (65536.0 * 16.0));
 208                 }
 209                 ao_k_height +=
 210                         (ao_k_t) AO_BOTH_K00_10 * ao_error_h +
 211                         (ao_k_t) AO_BOTH_K01_10 * ao_error_a;
 212                 ao_k_speed +=
 213                         (ao_k_t) AO_BOTH_K10_10 * ao_error_h +
 214                         (ao_k_t) AO_BOTH_K11_10 * ao_error_a;
 215                 ao_k_accel +=
 216                         (ao_k_t) AO_BOTH_K20_10 * ao_error_h +
 217                         (ao_k_t) AO_BOTH_K21_10 * ao_error_a;
 218                 return;
 219         }
 220         if (ao_flight_debug) {
 221                 printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 222                         ao_k_speed / (65536.0 * 16.0),
 223                         (double) ao_error_h, AO_BOTH_K10_100 / 65536.0,
 224                         (double) ao_error_a, AO_BOTH_K11_100 / 65536.0,
 225                         (ao_k_speed +
 226                          (ao_k_t) AO_BOTH_K10_100 * ao_error_h +
 227                          (ao_k_t) AO_BOTH_K11_100 * ao_error_a) / (65536.0 * 16.0));
 228         }
 229 #endif
 230         ao_k_height +=
 231                 (ao_k_t) AO_BOTH_K00_100 * ao_error_h +
 232                 (ao_k_t) AO_BOTH_K01_100 * ao_error_a;
 233         ao_k_speed +=
 234                 (ao_k_t) AO_BOTH_K10_100 * ao_error_h +
 235                 (ao_k_t) AO_BOTH_K11_100 * ao_error_a;
 236         ao_k_accel +=
 237                 (ao_k_t) AO_BOTH_K20_100 * ao_error_h +
 238                 (ao_k_t) AO_BOTH_K21_100 * ao_error_a;
 239 }
 240
 241 #else
 242
 243 static void
 244 ao_kalman_correct_accel(void)
 245 {
 246         ao_kalman_err_accel();
 247
 248         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
 249                 ao_k_height +=(ao_k_t) AO_ACCEL_K0_10 * ao_error_a;
 250                 ao_k_speed  += (ao_k_t) AO_ACCEL_K1_10 * ao_error_a;
 251                 ao_k_accel  += (ao_k_t) AO_ACCEL_K2_10 * ao_error_a;
 252                 return;
 253         }
 254         ao_k_height += (ao_k_t) AO_ACCEL_K0_100 * ao_error_a;
 255         ao_k_speed  += (ao_k_t) AO_ACCEL_K1_100 * ao_error_a;
 256         ao_k_accel  += (ao_k_t) AO_ACCEL_K2_100 * ao_error_a;
 257 }
 258
 259 #endif /* else FORCE_ACCEL */
 260 #endif /* HAS_ACCEL */
 261
 262 void
 263 ao_kalman(void)
 264 {
 265         ao_kalman_predict();
 266 #if HAS_ACCEL
 267         if (ao_flight_state <= ao_flight_coast) {
 268 #ifdef FORCE_ACCEL
 269                 ao_kalman_correct_accel();
 270 #else
 271                 ao_kalman_correct_both();
 272 #endif
 273         } else
 274 #endif
 275                 ao_kalman_correct_baro();
 276         ao_height = from_fix(ao_k_height);
 277         ao_speed = from_fix(ao_k_speed);
 278         ao_accel = from_fix(ao_k_accel);
 279         if (ao_height > ao_max_height)
 280                 ao_max_height = ao_height;
 281         ao_avg_height_scaled = ao_avg_height_scaled - ao_avg_height + ao_sample_height;
 282 #ifdef AO_FLIGHT_TEST
 283         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50)
 284                 ao_avg_height = (ao_avg_height_scaled + 1) >> 1;
 285         else if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5)
 286                 ao_avg_height = (ao_avg_height_scaled + 7) >> 4;
 287         else
 288 #endif
 289                 ao_avg_height = (ao_avg_height_scaled + 63) >> 7;
 290 }