gps_printloc.c

This a support library and assorted sample programs for interfacing

#include "as_gps.h"

/* Usage:  gps_printloc [#samples]
   Prints UTCtime, lat, long, height in meters
   until #samples lines are printed.  If #samples is zero, or missing,
   gps_printloc continues until interrupted.  Also, repeated identical
   samples are discarded (but a time discontinuity will be observed).
   Normally one sample per second is printed.
   Written 10-29-99 by [e-mail] (adapted from gps_average.c).
   Note: a neat way to show the effects of SA, is to graph via gnuplot:
      gps_printloc > gps_printloc.out    [kill after sufficient samples written]
      plot "gps_printloc.out" using ($2):($3)
      pause -1 "Press CR to continue"
      splot "gps_printloc.out" using ($2):($3):($4)
      pause -1 "Press CR to continue"
*/
int main(int argc, char *argv[])
{
  unsigned fix, count=0, samples;
  double lat,lgt,hgt;

  if(as_gps_open("/dev/gps"))
  {
    printf("Can't open device\n");
    exit(1);
  }

  if (argc > 1)
    samples = atoi(argv[1]);
  else
    samples = 0;

  while(!samples || count < samples)
  {
    void *data=NULL;
    unsigned char result = as_gps_handle_input(&data);

    if(result == AS_GPS_RCV_POSITION_DATA) 
    {
      AS_GPS_PositionData *pos = (AS_GPS_PositionData *)data;

      fix = pos->status & 0x0f;
      if((fix == 3 || fix == 4) /* at least a 2D or 3D fix */
	&& (lat!=pos->lat || lgt!=pos->lgt || hgt!=pos->hgt))
      {
        printf("%ld, %3.16f, %3.16f, %5.1f\n", pos->time, pos->lat, pos->lgt, pos->hgt);
	lat=pos->lat; lgt=pos->lgt; hgt=pos->hgt;
        count++;
      }
    }
    free(data);
  }

  as_gps_close(); 
}