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   1 #!/usr/bin/env nickle
   2
   3 /*
   4  * Copyright © 2013 Keith Packard <keithp@keithp.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  18  */
  19
  20 autoimport ParseArgs;
  21
  22 load "load_csv.5c"
  23 import load_csv;
  24
  25 load "matrix.5c"
  26 import matrix;
  27
  28 load "kalman_filter.5c"
  29 import kalman;
  30
  31 load "../util/atmosphere.5c"
  32
  33 real    height_scale = 1.0;
  34 real    accel_scale = 1.0;
  35 real    speed_scale = 1.0;
  36
  37 /*
  38  * State:
  39  *
  40  * x[0] = pressure
  41  * x[1] = delta pressure
  42  * x[2] = delta delta pressure
  43  */
  44
  45 /*
  46  * Measurement
  47  *
  48  * z[0] = pressure
  49  */
  50
  51 real default_σ_m = 5;
  52 real default_σ_h = 2.4;        /* pascals */
  53
  54 real[3,3] model_error(t, Φ) = multiply_mat_val ((real[3,3]) {
  55                 { t**5 / 20, t**4 / 8, t**3 / 6 },
  56                 { t**4 /  8, t**3 / 3, t**2 / 2 },
  57                 { t**3 /  6, t**2 / 2, t }
  58         }, Φ);
  59
  60 parameters_t param_baro(real t, real σ_m, real σ_h) {
  61         if (σ_m == 0) {
  62                 printf ("Using default σ_m\n");
  63                 σ_m = default_σ_m;
  64         }
  65         if (σ_h == 0) {
  66                 printf ("Using default σ_h\n");
  67                 σ_h = default_σ_h;
  68         }
  69
  70         σ_m = imprecise(σ_m) * accel_scale;
  71         σ_h = imprecise(σ_h) * height_scale;
  72
  73         t = imprecise(t);
  74         return (parameters_t) {
  75 /*
  76  * Equation computing state k from state k-1
  77  *
  78  * height = height- + velocity- * t + acceleration- * t² / 2
  79  * velocity = velocity- + acceleration- * t
  80  * acceleration = acceleration-
  81  */
  82                 .a = (real[3,3]) {
  83                         { 1, t * height_scale / speed_scale , t**2/2 * height_scale / accel_scale },
  84                         { 0, 1, t * speed_scale / accel_scale },
  85                         { 0, 0, 1 }
  86                 },
  87 /*
  88  * Model error covariance. The only inaccuracy in the
  89  * model is the assumption that acceleration is constant
  90  */
  91                 .q = model_error (t, σ_m**2),
  92
  93 /*
  94  * Measurement error covariance
  95  * Our sensors are independent, so
  96  * this matrix is zero off-diagonal
  97  */
  98                 .r = (real[1,1]) {
  99                         { σ_h ** 2 },
 100                 },
 101 /*
 102  * Extract measurements from state,
 103  * this just pulls out the height
 104  * values.
 105  */
 106                 .h = (real[1,3]) {
 107                         { 1, 0, 0 },
 108                 },
 109          };
 110 }
 111
 112 bool    just_kalman = true;
 113 real    accel_input_scale = 1;
 114
 115 real    error_avg;
 116
 117 void update_error_avg(real e) {
 118         if (e < 0)
 119                 e = -e;
 120
 121 #       if (e > 1000)
 122 #               e = 1000;
 123
 124         error_avg -= error_avg / 8;
 125         error_avg += (e * e) / 8;
 126 }
 127
 128 void run_flight(string name, file f, bool summary, real σ_m, real σ_h) {
 129         state_t current_both = {
 130                 .x = (real[3]) { 0, 0, 0 },
 131                 .p = (real[3,3]) { { 0 ... } ... },
 132         };
 133         state_t current_accel = current_both;
 134         state_t current_baro = current_both;
 135         real    t;
 136         real    kalman_apogee_time = -1;
 137         real    kalman_apogee = 0;
 138         real    raw_apogee_time_first;
 139         real    raw_apogee_time_last;
 140         real    raw_apogee = 0;
 141         real    speed = 0;
 142         real    prev_acceleration = 0;
 143         real    height, max_height = 0;
 144         state_t apogee_state;
 145         parameters_fast_t       fast_baro;
 146         real                    fast_delta_t = 0;
 147         bool                    fast = true;
 148         int                     speed_lock = 0;
 149
 150         error_avg = 0;
 151         for (;;) {
 152                 record_t        record = parse_record(f, 1.0);
 153                 if (record.done)
 154                         break;
 155                 if (is_uninit(&t))
 156                         t = record.time;
 157                 real delta_t = record.time - t;
 158                 if (delta_t < 0.096)
 159                         continue;
 160 #               delta_t = 0.096;        /* pretend that we're getting micropeak-rate data */
 161 #               record.time = record.time + delta_t;
 162                 t = record.time;
 163                 if (record.height > raw_apogee) {
 164                         raw_apogee_time_first = record.time;
 165                         raw_apogee = record.height;
 166                 }
 167                 if (record.height == raw_apogee)
 168                         raw_apogee_time_last = record.time;
 169
 170                 real    pressure = record.pressure;
 171
 172                 if (current_baro.x[0] == 0)
 173                         current_baro.x[0] = pressure;
 174
 175                 vec_t z_baro = (real[1]) { record.pressure * height_scale };
 176
 177                 real    error_h;
 178
 179                 if (fast) {
 180                         if (delta_t != fast_delta_t) {
 181                                 fast_baro = convert_to_fast(param_baro(delta_t, σ_m, σ_h));
 182                                 fast_delta_t = delta_t;
 183                         }
 184
 185                         current_baro.x = predict_fast(current_baro.x, fast_baro);
 186                         error_h = current_baro.x[0] - pressure;
 187                         current_baro.x = correct_fast(current_baro.x, z_baro, fast_baro);
 188                 } else {
 189                         parameters_t p_baro = param_baro(delta_t, σ_m, σ_h);
 190
 191                         state_t pred_baro = predict(current_baro, p_baro);
 192                         error_h = current_baro.x[0] - pressure;
 193                         state_t next_baro = correct(pred_baro, z_baro, p_baro);
 194                         current_baro = next_baro;
 195                 }
 196
 197                 update_error_avg(error_h);
 198
 199                 /* Don't check for maximum altitude if we're accelerating upwards */
 200                 if (current_baro.x[2] / accel_scale < -2 * σ_m)
 201                         speed_lock = 10;
 202                 else if (speed_lock > 0)
 203                         speed_lock--;
 204
 205                 height = pressure_to_altitude(current_baro.x[0] / height_scale);
 206                 if (speed_lock == 0 && height > max_height)
 207                         max_height = height;
 208
 209                 printf ("%16.8f %16.8f %16.8f %16.8f %16.8f %16.8f %16.8f %16.8f %16.8f %16.8f %d %d\n",
 210                         record.time,
 211                         record.pressure,
 212                         pressure_to_altitude(record.pressure),
 213                         current_baro.x[0] / height_scale,
 214                         current_baro.x[1] / speed_scale,
 215                         current_baro.x[2] / accel_scale,
 216                         height,
 217                         max_height,
 218                         error_h,
 219                         error_avg,
 220                         error_avg > 50000 ? 0 : 95000,
 221                         speed_lock > 0 ? 0 : 4500);
 222
 223                 if (kalman_apogee_time < 0) {
 224                         if (current_baro.x[1] > 1) {
 225                                 kalman_apogee = current_both.x[0];
 226                                 kalman_apogee_time = record.time;
 227                         }
 228                 }
 229         }
 230         real raw_apogee_time = (raw_apogee_time_last + raw_apogee_time_first) / 2;
 231         if (summary && !just_kalman) {
 232                 printf("%s: kalman (%8.2f m %6.2f s) raw (%8.2f m %6.2f s) error %6.2f s\n",
 233                        name,
 234                        kalman_apogee, kalman_apogee_time,
 235                        raw_apogee, raw_apogee_time,
 236                        kalman_apogee_time - raw_apogee_time);
 237         }
 238 }
 239
 240 void main() {
 241         bool    summary = false;
 242         int     user_argind = 1;
 243         real    time_step = 0.01;
 244         string  compute = "none";
 245         string  prefix = "AO_K";
 246         real    σ_m = default_σ_m;
 247         real    σ_h = default_σ_h;
 248
 249         ParseArgs::argdesc argd = {
 250                 .args = {
 251                         { .var = { .arg_flag = &summary },
 252                           .abbr = 's',
 253                           .name = "summary",
 254                           .desc = "Print a summary of the flight" },
 255                         { .var = { .arg_real = &time_step, },
 256                           .abbr = 't',
 257                           .name = "time",
 258                           .expr_name = "<time-step>",
 259                           .desc = "Set time step for convergence" },
 260                         { .var = { .arg_string = &prefix },
 261                           .abbr = 'p',
 262                           .name = "prefix",
 263                           .expr_name = "<prefix>",
 264                           .desc = "Prefix for compute output" },
 265                         { .var = { .arg_string = &compute },
 266                           .abbr = 'c',
 267                           .name = "compute",
 268                           .expr_name = "{baro,none}",
 269                           .desc = "Compute Kalman factor through convergence" },
 270                         { .var = { .arg_real = &σ_m },
 271                           .abbr = 'M',
 272                           .name = "model",
 273                           .expr_name = "<model-accel-error>",
 274                           .desc = "Model co-variance for acceleration" },
 275                         { .var = { .arg_real = &σ_h },
 276                           .abbr = 'H',
 277                           .name = "height",
 278                           .expr_name = "<measure-height-error>",
 279                           .desc = "Measure co-variance for height" },
 280                 },
 281
 282                 .unknown = &user_argind,
 283         };
 284
 285         ParseArgs::parseargs(&argd, &argv);
 286
 287         if (compute != "none") {
 288                 parameters_t    param;
 289
 290                 printf ("/* Kalman matrix for micro %s\n", compute);
 291                 printf (" *     step = %f\n", time_step);
 292                 printf (" *     σ_m = %f\n", σ_m);
 293                 switch (compute) {
 294                 case "baro":
 295                         printf (" *     σ_h = %f\n", σ_h);
 296                         param = param_baro(time_step, σ_m, σ_h);
 297                         break;
 298                 }
 299                 printf (" */\n\n");
 300                 mat_t k = converge(param);
 301                 int[] d = dims(k);
 302                 int time_inc = floor(1/time_step + 0.5);
 303                 for (int i = 0; i < d[0]; i++)
 304                         for (int j = 0; j < d[1]; j++) {
 305                                 string name;
 306                                 if (d[1] == 1)
 307                                         name = sprintf("%s_K%d_%d", prefix, i, time_inc);
 308                                 else
 309                                         name = sprintf("%s_K%d%d_%d", prefix, i, j, time_inc);
 310                                 printf ("#define %s to_fix_k(%12.10f)\n", name, k[i,j]);
 311                         }
 312                 printf ("\n");
 313                 exit(0);
 314         }
 315         string[dim(argv) - user_argind] rest = { [i] = argv[i+user_argind] };
 316
 317         #       height_scale = accel_scale = speed_scale = 1;
 318
 319         if (dim(rest) == 0)
 320                 run_flight("<stdin>", stdin, summary, σ_m, σ_h);
 321         else {
 322                 for (int i = 0; i < dim(rest); i++) {
 323                         twixt(file f = File::open(rest[i], "r"); File::close(f)) {
 324                                 run_flight(rest[i], f, summary, σ_m, σ_h);
 325                         }
 326                 }
 327         }
 328 }
 329 main();