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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 (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 (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 #if HAS_ACCEL
 100         ao_error_h_sq_avg -= ao_error_h_sq_avg >> 2;
 101         ao_error_h_sq_avg += (e * e) >> 2;
 102 #else
 103         ao_error_h_sq_avg -= ao_error_h_sq_avg >> 4;
 104         ao_error_h_sq_avg += (e * e) >> 4;
 105 #endif
 106
 107         if (ao_flight_state >= ao_flight_drogue)
 108                 return;
 109         height_distrust = ao_sample_alt - AO_MAX_BARO_HEIGHT;
 110 #if HAS_ACCEL
 111         /* speed is stored * 16, but we need to ramp between 200 and 328, so
 112          * we want to multiply by 2. The result is a shift by 3.
 113          */
 114         speed_distrust = (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) >> (4 - 1);
 115         if (speed_distrust <= 0)
 116                 speed_distrust = 0;
 117         else if (speed_distrust > height_distrust)
 118                 height_distrust = speed_distrust;
 119 #endif
 120         if (height_distrust > 0) {
 121 #ifdef AO_FLIGHT_TEST
 122                 int     old_ao_error_h = ao_error_h;
 123 #endif
 124                 if (height_distrust > 0x100)
 125                         height_distrust = 0x100;
 126                 ao_error_h = (ao_v_t) (((ao_k_t) ao_error_h * (0x100 - height_distrust)) >> 8);
 127 #ifdef AO_FLIGHT_TEST
 128                 if (ao_flight_debug) {
 129                         printf("over height %g over speed %g distrust: %g height: error %d -> %d\n",
 130                                (double) (ao_sample_alt - AO_MAX_BARO_HEIGHT),
 131                                (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) / 16.0,
 132                                height_distrust / 256.0,
 133                                old_ao_error_h, ao_error_h);
 134                 }
 135 #endif
 136         }
 137 }
 138
 139 static void
 140 ao_kalman_correct_baro(void)
 141 {
 142         ao_kalman_err_height();
 143 #ifdef AO_FLIGHT_TEST
 144         if (ao_sample_tick - ao_sample_prev_tick > 50) {
 145                 ao_k_height += (ao_k_t) AO_BARO_K0_1 * ao_error_h;
 146                 ao_k_speed  += (ao_k_t) AO_BARO_K1_1 * ao_error_h;
 147                 ao_k_accel  += (ao_k_t) AO_BARO_K2_1 * ao_error_h;
 148                 return;
 149         }
 150         if (ao_sample_tick - ao_sample_prev_tick > 5) {
 151                 ao_k_height += (ao_k_t) AO_BARO_K0_10 * ao_error_h;
 152                 ao_k_speed  += (ao_k_t) AO_BARO_K1_10 * ao_error_h;
 153                 ao_k_accel  += (ao_k_t) AO_BARO_K2_10 * ao_error_h;
 154                 return;
 155         }
 156 #endif
 157         ao_k_height += (ao_k_t) AO_BARO_K0_100 * ao_error_h;
 158         ao_k_speed  += (ao_k_t) AO_BARO_K1_100 * ao_error_h;
 159         ao_k_accel  += (ao_k_t) AO_BARO_K2_100 * ao_error_h;
 160 }
 161
 162 #if HAS_ACCEL
 163
 164 static void
 165 ao_kalman_err_accel(void)
 166 {
 167         ao_k_t  accel;
 168
 169         accel = (ao_config.accel_plus_g - ao_sample_accel) * ao_accel_scale;
 170
 171         /* Can't use ao_accel here as it is the pre-prediction value still */
 172         ao_error_a = (accel - ao_k_accel) >> 16;
 173 }
 174
 175 #ifndef FORCE_ACCEL
 176 static void
 177 ao_kalman_correct_both(void)
 178 {
 179         ao_kalman_err_height();
 180         ao_kalman_err_accel();
 181
 182 #ifdef AO_FLIGHT_TEST
 183         if (ao_sample_tick - ao_sample_prev_tick > 50) {
 184                 if (ao_flight_debug) {
 185                         printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 186                                 ao_k_speed / (65536.0 * 16.0),
 187                                 (double) ao_error_h, AO_BOTH_K10_1 / 65536.0,
 188                                 (double) ao_error_a, AO_BOTH_K11_1 / 65536.0,
 189                                 (ao_k_speed +
 190                                  (ao_k_t) AO_BOTH_K10_1 * ao_error_h +
 191                                  (ao_k_t) AO_BOTH_K11_1 * ao_error_a) / (65536.0 * 16.0));
 192                 }
 193                 ao_k_height +=
 194                         (ao_k_t) AO_BOTH_K00_1 * ao_error_h +
 195                         (ao_k_t) AO_BOTH_K01_1 * ao_error_a;
 196                 ao_k_speed +=
 197                         (ao_k_t) AO_BOTH_K10_1 * ao_error_h +
 198                         (ao_k_t) AO_BOTH_K11_1 * ao_error_a;
 199                 ao_k_accel +=
 200                         (ao_k_t) AO_BOTH_K20_1 * ao_error_h +
 201                         (ao_k_t) AO_BOTH_K21_1 * ao_error_a;
 202                 return;
 203         }
 204         if (ao_sample_tick - ao_sample_prev_tick > 5) {
 205                 if (ao_flight_debug) {
 206                         printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 207                                 ao_k_speed / (65536.0 * 16.0),
 208                                 (double) ao_error_h, AO_BOTH_K10_10 / 65536.0,
 209                                 (double) ao_error_a, AO_BOTH_K11_10 / 65536.0,
 210                                 (ao_k_speed +
 211                                  (ao_k_t) AO_BOTH_K10_10 * ao_error_h +
 212                                  (ao_k_t) AO_BOTH_K11_10 * ao_error_a) / (65536.0 * 16.0));
 213                 }
 214                 ao_k_height +=
 215                         (ao_k_t) AO_BOTH_K00_10 * ao_error_h +
 216                         (ao_k_t) AO_BOTH_K01_10 * ao_error_a;
 217                 ao_k_speed +=
 218                         (ao_k_t) AO_BOTH_K10_10 * ao_error_h +
 219                         (ao_k_t) AO_BOTH_K11_10 * ao_error_a;
 220                 ao_k_accel +=
 221                         (ao_k_t) AO_BOTH_K20_10 * ao_error_h +
 222                         (ao_k_t) AO_BOTH_K21_10 * ao_error_a;
 223                 return;
 224         }
 225         if (ao_flight_debug) {
 226                 printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 227                         ao_k_speed / (65536.0 * 16.0),
 228                         (double) ao_error_h, AO_BOTH_K10_100 / 65536.0,
 229                         (double) ao_error_a, AO_BOTH_K11_100 / 65536.0,
 230                         (ao_k_speed +
 231                          (ao_k_t) AO_BOTH_K10_100 * ao_error_h +
 232                          (ao_k_t) AO_BOTH_K11_100 * ao_error_a) / (65536.0 * 16.0));
 233         }
 234 #endif
 235         ao_k_height +=
 236                 (ao_k_t) AO_BOTH_K00_100 * ao_error_h +
 237                 (ao_k_t) AO_BOTH_K01_100 * ao_error_a;
 238         ao_k_speed +=
 239                 (ao_k_t) AO_BOTH_K10_100 * ao_error_h +
 240                 (ao_k_t) AO_BOTH_K11_100 * ao_error_a;
 241         ao_k_accel +=
 242                 (ao_k_t) AO_BOTH_K20_100 * ao_error_h +
 243                 (ao_k_t) AO_BOTH_K21_100 * ao_error_a;
 244 }
 245
 246 #else
 247
 248 static void
 249 ao_kalman_correct_accel(void)
 250 {
 251         ao_kalman_err_accel();
 252
 253         if (ao_sample_tick - ao_sample_prev_tick > 5) {
 254                 ao_k_height +=(ao_k_t) AO_ACCEL_K0_10 * ao_error_a;
 255                 ao_k_speed  += (ao_k_t) AO_ACCEL_K1_10 * ao_error_a;
 256                 ao_k_accel  += (ao_k_t) AO_ACCEL_K2_10 * ao_error_a;
 257                 return;
 258         }
 259         ao_k_height += (ao_k_t) AO_ACCEL_K0_100 * ao_error_a;
 260         ao_k_speed  += (ao_k_t) AO_ACCEL_K1_100 * ao_error_a;
 261         ao_k_accel  += (ao_k_t) AO_ACCEL_K2_100 * ao_error_a;
 262 }
 263
 264 #endif /* else FORCE_ACCEL */
 265 #endif /* HAS_ACCEL */
 266
 267 void
 268 ao_kalman(void)
 269 {
 270         ao_kalman_predict();
 271 #if HAS_ACCEL
 272         if (ao_flight_state <= ao_flight_coast) {
 273 #ifdef FORCE_ACCEL
 274                 ao_kalman_correct_accel();
 275 #else
 276                 ao_kalman_correct_both();
 277 #endif
 278         } else
 279 #endif
 280                 ao_kalman_correct_baro();
 281         ao_height = from_fix(ao_k_height);
 282         ao_speed = from_fix(ao_k_speed);
 283         ao_accel = from_fix(ao_k_accel);
 284         if (ao_height > ao_max_height)
 285                 ao_max_height = ao_height;
 286         ao_avg_height_scaled = ao_avg_height_scaled - ao_avg_height + ao_sample_height;
 287 #ifdef AO_FLIGHT_TEST
 288         if (ao_sample_tick - ao_sample_prev_tick > 50)
 289                 ao_avg_height = (ao_avg_height_scaled + 1) >> 1;
 290         else if (ao_sample_tick - ao_sample_prev_tick > 5)
 291                 ao_avg_height = (ao_avg_height_scaled + 7) >> 4;
 292         else
 293 #endif
 294                 ao_avg_height = (ao_avg_height_scaled + 63) >> 7;
 295 }