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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; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 #ifndef AO_FLIGHT_TEST
  19 #include "ao.h"
  20 #include "ao_flight.h"
  21 #endif
  22
  23 #include "ao_sample.h"
  24 #include "ao_kalman.h"
  25
  26 static __pdata ao_k_t           ao_k_height;
  27 static __pdata ao_k_t           ao_k_speed;
  28 static __pdata ao_k_t           ao_k_accel;
  29
  30 #define AO_K_STEP_100           to_fix_v(0.01)
  31 #define AO_K_STEP_2_2_100       to_fix_v(0.00005)
  32
  33 #define AO_K_STEP_10            to_fix_v(0.1)
  34 #define AO_K_STEP_2_2_10        to_fix_v(0.005)
  35
  36 #define AO_K_STEP_1             to_fix_v(1)
  37 #define AO_K_STEP_2_2_1         to_fix_v(0.5)
  38
  39 __pdata ao_v_t                  ao_height;
  40 __pdata ao_v_t                  ao_speed;
  41 __pdata ao_v_t                  ao_accel;
  42 __xdata ao_v_t                  ao_max_height;
  43 static __pdata ao_k_t           ao_avg_height_scaled;
  44 __xdata ao_v_t                  ao_avg_height;
  45
  46 __pdata ao_v_t                  ao_error_h;
  47 __pdata ao_v_t                  ao_error_h_sq_avg;
  48
  49 #if HAS_ACCEL
  50 __pdata ao_v_t                  ao_error_a;
  51 #endif
  52
  53 static void
  54 ao_kalman_predict(void)
  55 {
  56 #ifdef AO_FLIGHT_TEST
  57         if (ao_sample_tick - ao_sample_prev_tick > 50) {
  58                 ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_1 +
  59                                 (ao_k_t) ao_accel * AO_K_STEP_2_2_1) >> 4;
  60                 ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_1;
  61
  62                 return;
  63         }
  64         if (ao_sample_tick - ao_sample_prev_tick > 5) {
  65                 ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_10 +
  66                                 (ao_k_t) ao_accel * AO_K_STEP_2_2_10) >> 4;
  67                 ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_10;
  68
  69                 return;
  70         }
  71         if (ao_flight_debug) {
  72                 printf ("predict speed %g + (%g * %g) = %g\n",
  73                         ao_k_speed / (65536.0 * 16.0), ao_accel / 16.0, AO_K_STEP_100 / 65536.0,
  74                         (ao_k_speed + (ao_k_t) ao_accel * AO_K_STEP_100) / (65536.0 * 16.0));
  75         }
  76 #endif
  77         ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_100 +
  78                         (ao_k_t) ao_accel * AO_K_STEP_2_2_100) >> 4;
  79         ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_100;
  80 }
  81
  82 static void
  83 ao_kalman_err_height(void)
  84 {
  85         ao_v_t  e;
  86         ao_v_t height_distrust;
  87 #if HAS_ACCEL
  88         ao_v_t  speed_distrust;
  89 #endif
  90
  91         ao_error_h = ao_sample_height - (ao_v_t) (ao_k_height >> 16);
  92
  93         e = ao_error_h;
  94         if (e < 0)
  95                 e = -e;
  96         if (e > 127)
  97                 e = 127;
  98 #if HAS_ACCEL
  99         ao_error_h_sq_avg -= ao_error_h_sq_avg >> 2;
 100         ao_error_h_sq_avg += (e * e) >> 2;
 101 #else
 102         ao_error_h_sq_avg -= ao_error_h_sq_avg >> 4;
 103         ao_error_h_sq_avg += (e * e) >> 4;
 104 #endif
 105
 106         if (ao_flight_state >= ao_flight_drogue)
 107                 return;
 108         height_distrust = ao_sample_alt - AO_MAX_BARO_HEIGHT;
 109 #if HAS_ACCEL
 110         /* speed is stored * 16, but we need to ramp between 200 and 328, so
 111          * we want to multiply by 2. The result is a shift by 3.
 112          */
 113         speed_distrust = (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) >> (4 - 1);
 114         if (speed_distrust <= 0)
 115                 speed_distrust = 0;
 116         else if (speed_distrust > height_distrust)
 117                 height_distrust = speed_distrust;
 118 #endif
 119         if (height_distrust > 0) {
 120 #ifdef AO_FLIGHT_TEST
 121                 int     old_ao_error_h = ao_error_h;
 122 #endif
 123                 if (height_distrust > 0x100)
 124                         height_distrust = 0x100;
 125                 ao_error_h = (ao_v_t) (((ao_k_t) ao_error_h * (0x100 - height_distrust)) >> 8);
 126 #ifdef AO_FLIGHT_TEST
 127                 if (ao_flight_debug) {
 128                         printf("over height %g over speed %g distrust: %g height: error %d -> %d\n",
 129                                (double) (ao_sample_alt - AO_MAX_BARO_HEIGHT),
 130                                (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) / 16.0,
 131                                height_distrust / 256.0,
 132                                old_ao_error_h, ao_error_h);
 133                 }
 134 #endif
 135         }
 136 }
 137
 138 static void
 139 ao_kalman_correct_baro(void)
 140 {
 141         ao_kalman_err_height();
 142 #ifdef AO_FLIGHT_TEST
 143         if (ao_sample_tick - ao_sample_prev_tick > 50) {
 144                 ao_k_height += (ao_k_t) AO_BARO_K0_1 * ao_error_h;
 145                 ao_k_speed  += (ao_k_t) AO_BARO_K1_1 * ao_error_h;
 146                 ao_k_accel  += (ao_k_t) AO_BARO_K2_1 * ao_error_h;
 147                 return;
 148         }
 149         if (ao_sample_tick - ao_sample_prev_tick > 5) {
 150                 ao_k_height += (ao_k_t) AO_BARO_K0_10 * ao_error_h;
 151                 ao_k_speed  += (ao_k_t) AO_BARO_K1_10 * ao_error_h;
 152                 ao_k_accel  += (ao_k_t) AO_BARO_K2_10 * ao_error_h;
 153                 return;
 154         }
 155 #endif
 156         ao_k_height += (ao_k_t) AO_BARO_K0_100 * ao_error_h;
 157         ao_k_speed  += (ao_k_t) AO_BARO_K1_100 * ao_error_h;
 158         ao_k_accel  += (ao_k_t) AO_BARO_K2_100 * ao_error_h;
 159 }
 160
 161 #if HAS_ACCEL
 162
 163 static void
 164 ao_kalman_err_accel(void)
 165 {
 166         ao_k_t  accel;
 167
 168         accel = (ao_config.accel_plus_g - ao_sample_accel) * ao_accel_scale;
 169
 170         /* Can't use ao_accel here as it is the pre-prediction value still */
 171         ao_error_a = (accel - ao_k_accel) >> 16;
 172 }
 173
 174 #ifndef FORCE_ACCEL
 175 static void
 176 ao_kalman_correct_both(void)
 177 {
 178         ao_kalman_err_height();
 179         ao_kalman_err_accel();
 180
 181 #ifdef AO_FLIGHT_TEST
 182         if (ao_sample_tick - ao_sample_prev_tick > 50) {
 183                 if (ao_flight_debug) {
 184                         printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 185                                 ao_k_speed / (65536.0 * 16.0),
 186                                 (double) ao_error_h, AO_BOTH_K10_1 / 65536.0,
 187                                 (double) ao_error_a, AO_BOTH_K11_1 / 65536.0,
 188                                 (ao_k_speed +
 189                                  (ao_k_t) AO_BOTH_K10_1 * ao_error_h +
 190                                  (ao_k_t) AO_BOTH_K11_1 * ao_error_a) / (65536.0 * 16.0));
 191                 }
 192                 ao_k_height +=
 193                         (ao_k_t) AO_BOTH_K00_1 * ao_error_h +
 194                         (ao_k_t) AO_BOTH_K01_1 * ao_error_a;
 195                 ao_k_speed +=
 196                         (ao_k_t) AO_BOTH_K10_1 * ao_error_h +
 197                         (ao_k_t) AO_BOTH_K11_1 * ao_error_a;
 198                 ao_k_accel +=
 199                         (ao_k_t) AO_BOTH_K20_1 * ao_error_h +
 200                         (ao_k_t) AO_BOTH_K21_1 * ao_error_a;
 201                 return;
 202         }
 203         if (ao_sample_tick - ao_sample_prev_tick > 5) {
 204                 if (ao_flight_debug) {
 205                         printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 206                                 ao_k_speed / (65536.0 * 16.0),
 207                                 (double) ao_error_h, AO_BOTH_K10_10 / 65536.0,
 208                                 (double) ao_error_a, AO_BOTH_K11_10 / 65536.0,
 209                                 (ao_k_speed +
 210                                  (ao_k_t) AO_BOTH_K10_10 * ao_error_h +
 211                                  (ao_k_t) AO_BOTH_K11_10 * ao_error_a) / (65536.0 * 16.0));
 212                 }
 213                 ao_k_height +=
 214                         (ao_k_t) AO_BOTH_K00_10 * ao_error_h +
 215                         (ao_k_t) AO_BOTH_K01_10 * ao_error_a;
 216                 ao_k_speed +=
 217                         (ao_k_t) AO_BOTH_K10_10 * ao_error_h +
 218                         (ao_k_t) AO_BOTH_K11_10 * ao_error_a;
 219                 ao_k_accel +=
 220                         (ao_k_t) AO_BOTH_K20_10 * ao_error_h +
 221                         (ao_k_t) AO_BOTH_K21_10 * ao_error_a;
 222                 return;
 223         }
 224         if (ao_flight_debug) {
 225                 printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
 226                         ao_k_speed / (65536.0 * 16.0),
 227                         (double) ao_error_h, AO_BOTH_K10_100 / 65536.0,
 228                         (double) ao_error_a, AO_BOTH_K11_100 / 65536.0,
 229                         (ao_k_speed +
 230                          (ao_k_t) AO_BOTH_K10_100 * ao_error_h +
 231                          (ao_k_t) AO_BOTH_K11_100 * ao_error_a) / (65536.0 * 16.0));
 232         }
 233 #endif
 234         ao_k_height +=
 235                 (ao_k_t) AO_BOTH_K00_100 * ao_error_h +
 236                 (ao_k_t) AO_BOTH_K01_100 * ao_error_a;
 237         ao_k_speed +=
 238                 (ao_k_t) AO_BOTH_K10_100 * ao_error_h +
 239                 (ao_k_t) AO_BOTH_K11_100 * ao_error_a;
 240         ao_k_accel +=
 241                 (ao_k_t) AO_BOTH_K20_100 * ao_error_h +
 242                 (ao_k_t) AO_BOTH_K21_100 * ao_error_a;
 243 }
 244
 245 #else
 246
 247 static void
 248 ao_kalman_correct_accel(void)
 249 {
 250         ao_kalman_err_accel();
 251
 252         if (ao_sample_tick - ao_sample_prev_tick > 5) {
 253                 ao_k_height +=(ao_k_t) AO_ACCEL_K0_10 * ao_error_a;
 254                 ao_k_speed  += (ao_k_t) AO_ACCEL_K1_10 * ao_error_a;
 255                 ao_k_accel  += (ao_k_t) AO_ACCEL_K2_10 * ao_error_a;
 256                 return;
 257         }
 258         ao_k_height += (ao_k_t) AO_ACCEL_K0_100 * ao_error_a;
 259         ao_k_speed  += (ao_k_t) AO_ACCEL_K1_100 * ao_error_a;
 260         ao_k_accel  += (ao_k_t) AO_ACCEL_K2_100 * ao_error_a;
 261 }
 262
 263 #endif /* else FORCE_ACCEL */
 264 #endif /* HAS_ACCEL */
 265
 266 void
 267 ao_kalman(void)
 268 {
 269         ao_kalman_predict();
 270 #if HAS_ACCEL
 271         if (ao_flight_state <= ao_flight_coast) {
 272 #ifdef FORCE_ACCEL
 273                 ao_kalman_correct_accel();
 274 #else
 275                 ao_kalman_correct_both();
 276 #endif
 277         } else
 278 #endif
 279                 ao_kalman_correct_baro();
 280         ao_height = from_fix(ao_k_height);
 281         ao_speed = from_fix(ao_k_speed);
 282         ao_accel = from_fix(ao_k_accel);
 283         if (ao_height > ao_max_height)
 284                 ao_max_height = ao_height;
 285         ao_avg_height_scaled = ao_avg_height_scaled - ao_avg_height + ao_sample_height;
 286 #ifdef AO_FLIGHT_TEST
 287         if (ao_sample_tick - ao_sample_prev_tick > 50)
 288                 ao_avg_height = (ao_avg_height_scaled + 1) >> 1;
 289         else if (ao_sample_tick - ao_sample_prev_tick > 5)
 290                 ao_avg_height = (ao_avg_height_scaled + 7) >> 4;
 291         else
 292 #endif
 293                 ao_avg_height = (ao_avg_height_scaled + 63) >> 7;
 294 }