git.gag.com Git - fw/altos/blob - aoview/aoview_state.c

   1 /*
   2  * Copyright © 2009 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 #include "aoview.h"
  19 #include <math.h>
  20
  21 static int      pad_pres;
  22 static int      pad_accel;
  23
  24 static int      pad_pres_total;
  25 static int      pad_accel_total;
  26 static double   pad_lat_total;
  27 static double   pad_lon_total;
  28 static int      pad_alt_total;
  29 static int      npad;
  30 static int      prev_tick;
  31 static double   prev_accel;
  32 static double   velocity;
  33 static double   pad_lat;
  34 static double   pad_lon;
  35 static double   pad_alt;
  36
  37 #define NUM_PAD_SAMPLES 50
  38
  39
  40
  41 static void
  42 aoview_great_circle (double start_lat, double start_lon,
  43                      double end_lat, double end_lon,
  44                      double *dist, double *bearing)
  45 {
  46         double rad = M_PI / 180;
  47         double earth_radius = 6371.2;
  48         double a = (90 - start_lat) * rad;
  49         double b = (90 - end_lat) * rad;
  50         double phi = (end_lon - start_lon) * rad;
  51         double cosr = cos(a) * cos(b) + sin(a) * sin(b) * cos(phi);
  52         double r = acos(cosr);
  53         double rdist = earth_radius * r;
  54         double sinth = sin(phi) * sin(b) / sin(r);
  55         double th = asin(sinth) / rad;
  56         *dist = rdist;
  57         *bearing = th;
  58 }
  59
  60 void
  61 aoview_state_notify(struct aostate *state)
  62 {
  63         int     altitude;
  64         double  accel;
  65         double  velocity_change;
  66         int     ticks;
  67         double  dist;
  68         double  bearing;
  69
  70         if (!strcmp(state->state, "pad")) {
  71                 if (npad < NUM_PAD_SAMPLES) {
  72                         pad_accel_total += state->accel;
  73                         pad_pres_total += state->pres;
  74                         pad_lat_total += state->lat;
  75                         pad_lon_total += state->lon;
  76                         pad_alt_total += state->alt;
  77                         npad++;
  78                         velocity = 0;
  79                 }
  80                 if (npad <= NUM_PAD_SAMPLES) {
  81                         pad_pres = pad_pres_total / npad;
  82                         pad_accel = pad_accel_total / npad;
  83                         pad_lat = pad_lat_total / npad;
  84                         pad_lon = pad_lon_total / npad;
  85                         pad_alt = pad_alt_total / npad;
  86                 }
  87         }
  88         altitude = aoview_pres_to_altitude(state->pres) - aoview_pres_to_altitude(pad_pres);
  89         accel = (pad_accel - state->accel) / 264.8 *  9.80665;
  90         velocity_change = (accel + prev_accel) / 2.0;
  91         ticks = state->tick - prev_tick;
  92         velocity -= velocity_change * (ticks / 100.0);
  93
  94         prev_accel = accel;
  95         prev_tick = state->tick;
  96         printf ("Pad altitude: %dm\n", aoview_pres_to_altitude(pad_pres));
  97         printf ("AGL: %dm\n", altitude);
  98         printf ("Acceleration: %gm/s²\n", accel);
  99         printf ("Velocity: %gm/s\n", velocity);
 100         printf ("Lat: %g\n", state->lat);
 101         printf ("Lon: %g\n", state->lon);
 102         printf ("GPS alt: %d\n", state->alt);
 103         aoview_great_circle(pad_lat, pad_lon, state->lat, state->lon,
 104                             &dist, &bearing);
 105         printf ("Course: %gkm %g°\n", dist, bearing);
 106 }
 107
 108 void
 109 aoview_state_init(GladeXML *xml)
 110 {
 111 }