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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 #if !HAS_ACCEL
  49 __pdata ao_v_t                  ao_error_h_sq_avg;
  50 #endif
  51
  52 #if HAS_ACCEL
  53 __pdata ao_v_t                  ao_error_a;
  54 #endif
  55
  56 static void
  57 ao_kalman_predict(void)
  58 {
  59 #ifdef AO_FLIGHT_TEST
  60         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
  61                 ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_1 +
  62                                 (ao_k_t) ao_accel * AO_K_STEP_2_2_1) >> 4;
  63                 ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_1;
  64
  65                 return;
  66         }
  67         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
  68                 ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_10 +
  69                                 (ao_k_t) ao_accel * AO_K_STEP_2_2_10) >> 4;
  70                 ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_10;
  71
  72                 return;
  73         }
  74         if (ao_flight_debug) {
  75                 printf ("predict speed %g + (%g * %g) = %g\n",
  76                         ao_k_speed / (65536.0 * 16.0), ao_accel / 16.0, AO_K_STEP_100 / 65536.0,
  77                         (ao_k_speed + (ao_k_t) ao_accel * AO_K_STEP_100) / (65536.0 * 16.0));
  78         }
  79 #endif
  80         ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_100 +
  81                         (ao_k_t) ao_accel * AO_K_STEP_2_2_100) >> 4;
  82         ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_100;
  83 }
  84
  85 static void
  86 ao_kalman_err_height(void)
  87 {
  88 #if !HAS_ACCEL
  89         ao_v_t  e;
  90 #endif
  91         ao_v_t height_distrust;
  92 #if HAS_ACCEL
  93         ao_v_t  speed_distrust;
  94 #endif
  95
  96         ao_error_h = ao_sample_height - (ao_v_t) (ao_k_height >> 16);
  97
  98 #if !HAS_ACCEL
  99         e = ao_error_h;
 100         if (e < 0)
 101                 e = -e;
 102         if (e > 127)
 103                 e = 127;
 104         ao_error_h_sq_avg -= ao_error_h_sq_avg >> 4;
 105         ao_error_h_sq_avg += (e * e) >> 4;
 106 #endif
 107
 108         if (ao_flight_state >= ao_flight_drogue)
 109                 return;
 110         height_distrust = ao_sample_alt - AO_MAX_BARO_HEIGHT;
 111 #if HAS_ACCEL
 112         /* speed is stored * 16, but we need to ramp between 248 and 328, so
 113          * we want to multiply by 2. The result is a shift by 3.
 114          */
 115         speed_distrust = (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) >> (4 - 1);
 116         if (speed_distrust > AO_MAX_SPEED_DISTRUST)
 117                 speed_distrust = AO_MAX_SPEED_DISTRUST;
 118         if (speed_distrust > height_distrust)
 119                 height_distrust = speed_distrust;
 120 #endif
 121         if (height_distrust > 0) {
 122 #ifdef AO_FLIGHT_TEST
 123                 int     old_ao_error_h = ao_error_h;
 124 #endif
 125                 if (height_distrust > 0x100)
 126                         height_distrust = 0x100;
 127                 ao_error_h = (ao_v_t) (((ao_k_t) ao_error_h * (0x100 - height_distrust)) >> 8);
 128 #ifdef AO_FLIGHT_TEST
 129                 if (ao_flight_debug) {
 130                         printf("over height %g over speed %g distrust: %g height: error %d -> %d\n",
 131                                (double) (ao_sample_alt - AO_MAX_BARO_HEIGHT),
 132                                (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) / 16.0,
 133                                height_distrust / 256.0,
 134                                old_ao_error_h, ao_error_h);
 135                 }
 136 #endif
 137         }
 138 }
 139
 140 static void
 141 ao_kalman_correct_baro(void)
 142 {
 143         ao_kalman_err_height();
 144 #ifdef AO_FLIGHT_TEST
 145         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
 146                 ao_k_height += (ao_k_t) AO_BARO_K0_1 * ao_error_h;
 147                 ao_k_speed  += (ao_k_t) AO_BARO_K1_1 * ao_error_h;
 148                 ao_k_accel  += (ao_k_t) AO_BARO_K2_1 * ao_error_h;
 149                 return;
 150         }
 151         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
 152                 ao_k_height += (ao_k_t) AO_BARO_K0_10 * ao_error_h;
 153                 ao_k_speed  += (ao_k_t) AO_BARO_K1_10 * ao_error_h;
 154                 ao_k_accel  += (ao_k_t) AO_BARO_K2_10 * ao_error_h;
 155                 return;
 156         }
 157 #endif
 158         ao_k_height += (ao_k_t) AO_BARO_K0_100 * ao_error_h;
 159         ao_k_speed  += (ao_k_t) AO_BARO_K1_100 * ao_error_h;
 160         ao_k_accel  += (ao_k_t) AO_BARO_K2_100 * ao_error_h;
 161 }
 162
 163 #if HAS_ACCEL
 164
 165 static void
 166 ao_kalman_err_accel(void)
 167 {
 168         ao_k_t  accel;
 169
 170         accel = (ao_config.accel_plus_g - ao_sample_accel) * ao_accel_scale;
 171
 172         /* Can't use ao_accel here as it is the pre-prediction value still */
 173         ao_error_a = (accel - ao_k_accel) >> 16;
 174 }
 175
 176 #ifndef FORCE_ACCEL
 177 static void
 178 ao_kalman_correct_both(void)
 179 {
 180         ao_kalman_err_height();
 181         ao_kalman_err_accel();
 182
 183 #ifdef AO_FLIGHT_TEST
 184         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
 185                 if (ao_flight_debug) {
 186                         printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 187                                 ao_k_speed / (65536.0 * 16.0),
 188                                 (double) ao_error_h, AO_BOTH_K10_1 / 65536.0,
 189                                 (double) ao_error_a, AO_BOTH_K11_1 / 65536.0,
 190                                 (ao_k_speed +
 191                                  (ao_k_t) AO_BOTH_K10_1 * ao_error_h +
 192                                  (ao_k_t) AO_BOTH_K11_1 * ao_error_a) / (65536.0 * 16.0));
 193                 }
 194                 ao_k_height +=
 195                         (ao_k_t) AO_BOTH_K00_1 * ao_error_h +
 196                         (ao_k_t) AO_BOTH_K01_1 * ao_error_a;
 197                 ao_k_speed +=
 198                         (ao_k_t) AO_BOTH_K10_1 * ao_error_h +
 199                         (ao_k_t) AO_BOTH_K11_1 * ao_error_a;
 200                 ao_k_accel +=
 201                         (ao_k_t) AO_BOTH_K20_1 * ao_error_h +
 202                         (ao_k_t) AO_BOTH_K21_1 * ao_error_a;
 203                 return;
 204         }
 205         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
 206                 if (ao_flight_debug) {
 207                         printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 208                                 ao_k_speed / (65536.0 * 16.0),
 209                                 (double) ao_error_h, AO_BOTH_K10_10 / 65536.0,
 210                                 (double) ao_error_a, AO_BOTH_K11_10 / 65536.0,
 211                                 (ao_k_speed +
 212                                  (ao_k_t) AO_BOTH_K10_10 * ao_error_h +
 213                                  (ao_k_t) AO_BOTH_K11_10 * ao_error_a) / (65536.0 * 16.0));
 214                 }
 215                 ao_k_height +=
 216                         (ao_k_t) AO_BOTH_K00_10 * ao_error_h +
 217                         (ao_k_t) AO_BOTH_K01_10 * ao_error_a;
 218                 ao_k_speed +=
 219                         (ao_k_t) AO_BOTH_K10_10 * ao_error_h +
 220                         (ao_k_t) AO_BOTH_K11_10 * ao_error_a;
 221                 ao_k_accel +=
 222                         (ao_k_t) AO_BOTH_K20_10 * ao_error_h +
 223                         (ao_k_t) AO_BOTH_K21_10 * ao_error_a;
 224                 return;
 225         }
 226         if (ao_flight_debug) {
 227                 printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 228                         ao_k_speed / (65536.0 * 16.0),
 229                         (double) ao_error_h, AO_BOTH_K10_100 / 65536.0,
 230                         (double) ao_error_a, AO_BOTH_K11_100 / 65536.0,
 231                         (ao_k_speed +
 232                          (ao_k_t) AO_BOTH_K10_100 * ao_error_h +
 233                          (ao_k_t) AO_BOTH_K11_100 * ao_error_a) / (65536.0 * 16.0));
 234         }
 235 #endif
 236         ao_k_height +=
 237                 (ao_k_t) AO_BOTH_K00_100 * ao_error_h +
 238                 (ao_k_t) AO_BOTH_K01_100 * ao_error_a;
 239         ao_k_speed +=
 240                 (ao_k_t) AO_BOTH_K10_100 * ao_error_h +
 241                 (ao_k_t) AO_BOTH_K11_100 * ao_error_a;
 242         ao_k_accel +=
 243                 (ao_k_t) AO_BOTH_K20_100 * ao_error_h +
 244                 (ao_k_t) AO_BOTH_K21_100 * ao_error_a;
 245 }
 246
 247 #else
 248
 249 static void
 250 ao_kalman_correct_accel(void)
 251 {
 252         ao_kalman_err_accel();
 253
 254         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
 255                 ao_k_height +=(ao_k_t) AO_ACCEL_K0_10 * ao_error_a;
 256                 ao_k_speed  += (ao_k_t) AO_ACCEL_K1_10 * ao_error_a;
 257                 ao_k_accel  += (ao_k_t) AO_ACCEL_K2_10 * ao_error_a;
 258                 return;
 259         }
 260         ao_k_height += (ao_k_t) AO_ACCEL_K0_100 * ao_error_a;
 261         ao_k_speed  += (ao_k_t) AO_ACCEL_K1_100 * ao_error_a;
 262         ao_k_accel  += (ao_k_t) AO_ACCEL_K2_100 * ao_error_a;
 263 }
 264
 265 #endif /* else FORCE_ACCEL */
 266 #endif /* HAS_ACCEL */
 267
 268 void
 269 ao_kalman(void)
 270 {
 271         ao_kalman_predict();
 272 #if HAS_ACCEL
 273         if (ao_flight_state <= ao_flight_coast) {
 274 #ifdef FORCE_ACCEL
 275                 ao_kalman_correct_accel();
 276 #else
 277                 ao_kalman_correct_both();
 278 #endif
 279         } else
 280 #endif
 281                 ao_kalman_correct_baro();
 282         ao_height = from_fix(ao_k_height);
 283         ao_speed = from_fix(ao_k_speed);
 284         ao_accel = from_fix(ao_k_accel);
 285         if (ao_height > ao_max_height)
 286                 ao_max_height = ao_height;
 287         ao_avg_height_scaled = ao_avg_height_scaled - ao_avg_height + ao_sample_height;
 288 #ifdef AO_FLIGHT_TEST
 289         if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50)
 290                 ao_avg_height = (ao_avg_height_scaled + 1) >> 1;
 291         else if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5)
 292                 ao_avg_height = (ao_avg_height_scaled + 7) >> 4;
 293         else
 294 #endif
 295                 ao_avg_height = (ao_avg_height_scaled + 63) >> 7;
 296 }