buf = conmalloc( strlen( OGSDataDir) + strlen( infile) + 1);  strcpy( buf, OGSDataDir);  strcat( buf, infile);  if ((in = fopen( buf, "rt")) == NULL)  {    printf( "error opening '%s'.\n", buf);    for ( id=1; id<=32; id++)    {      gps_alm[id].week = gps_week-1;      gps_alm[id].inc  = 1.0;    }  }  else  {    status = warm_start;    while ( !feof( in))                // GB: replaced eof() by feof()    {      fscanf( in, "%45c", &header);      fscanf( in, "%27c", &text);      fscanf( in, "%d", &id);      fscanf( in, "%27c", &text);      fscanf( in, "%i", &health);      fscanf( in, "%27c", &text);      fscanf( in, "%f", &eccen);      fscanf( in, "%27c", &text);      fscanf( in, "%f", &toa);      fscanf( in, "%27c", &text);      fscanf( in, "%f", &rinc);      fscanf( in, "%27c", &text);      fscanf( in, "%f", &rras);      fscanf( in, "%27c", &text);      fscanf( in, "%f", &sqra);      fscanf( in, "%27c", &text);      fscanf( in, "%f", &ratoa);      fscanf( in, "%27c", &text);      fscanf( in, "%f", &aopg);      fscanf( in, "%27c", &text);      fscanf( in, "%f", &rma);      fscanf( in, "%27c", &text);      fscanf( in, "%f", &af0);      fscanf( in, "%27c", &text);      fscanf( in, "%f", &af1);      fscanf( in, "%27c", &text);      fscanf( in, "%i", &week);      fscanf( in, "%c", &trailer);      gps_alm[id].health   = health;      gps_alm[id].week     = week;      gps_alm[id].toa      = toa;      gps_alm[id].ety      = eccen;      gps_alm[id].toa      = toa;      gps_alm[id].inc      = rinc;      gps_alm[id].omegadot = rras;      gps_alm[id].sqra     = sqra;      gps_alm[id].omega0   = ratoa;      gps_alm[id].w        = aopg;      gps_alm[id].ma       = rma;      gps_alm[id].af0      = af0;      gps_alm[id].af1      = af1;      gps_alm[id].sat_file = 0;      if (gps_alm[id].sqra > 0.0)         gps_alm[id].w = 19964981.84/pow(gps_alm[id].sqra,3);    }    fclose( in);    alm_gps_week = week;    alm_toa      = toa;  }  if ( buf)    free( buf);  return;}/*******************************************************************************FUNCTION read_ephemeris()RETURNS  None.PARAMETERS None.PURPOSE  This function WRITTEN BY  Clifford Kelley*******************************************************************************/void read_ephemeris( void){  int     id,health,week;  double  toc,toe;  double  crc, crs, cic, cis, cuc, cus, tgd, ety, inc0, omegadot, w0, w, ma;  double  daf0, daf1, daf2, esqra;  float   d_toe;  char infile[] = "current.eph";  char *buf;  FILE *in;  buf = conmalloc( strlen( OGSDataDir) + strlen( infile) + 1);  strcpy( buf, OGSDataDir);  strcat( buf, infile);  if (( in = fopen( buf, "rt")) == NULL)  {    printf( "error opening '%s'.\n", buf);  }  else  {    while ( !feof( in))                // GB: replaced eof() by feof()    {      fscanf( in, "%37c", &header);      fscanf( in, "%27c", &text);      fscanf( in, "%i", &id);      fscanf( in, "%27c", &text);      fscanf( in, "%i", &health);      fscanf( in, "%27c", &text);      fscanf( in, "%i", &week);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &toe);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &toc);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &tgd);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &daf0);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &daf1);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &daf2);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &ety);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &inc0);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &omegadot);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &esqra);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &w0);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &w);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &ma);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &cuc);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &cus);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &crc);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &crs);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &cic);      fscanf( in, "%27c", &text);      fscanf( in, "%le", &cis);      fscanf( in, "%c", &trailer);      d_toe = clock_tow-toe;      if ( d_toe > 302400.0)         d_toe = d_toe-604800.0;      else if (d_toe < -302400.0)        d_toe = d_toe + 604800.0;////    If week is current and time is less than 2 hours old use for hot start//    note: gps_week is computed from the PCs real time clock//          and does not roll over at 1024//      if ( week == (gps_week % 1024) && fabs( d_toe) < 7200.0)         gps_eph[id].valid=1;      gps_eph[id].health   = health;      gps_eph[id].week     = week;      gps_eph[id].toe      = toe;      gps_eph[id].toc      = toc;      gps_eph[id].tgd      = tgd;      gps_eph[id].af0      = daf0;      gps_eph[id].af1      = daf1;      gps_eph[id].af2      = daf2;      gps_eph[id].ety      = ety;      gps_eph[id].inc0     = inc0;      gps_eph[id].omegadot = omegadot;      gps_eph[id].sqra     = esqra;      gps_eph[id].omega0       = w0;      gps_eph[id].w        = w;      gps_eph[id].ma       = ma;      gps_eph[id].cuc      = cuc;      gps_eph[id].cus      = cus;      gps_eph[id].crc      = crc;      gps_eph[id].crs      = crs;      gps_eph[id].cic      = cic;      gps_eph[id].cis      = cis;      if (gps_eph[id].sqra > 0.0)         gps_eph[id].wm = 19964981.84 / pow( gps_eph[id].sqra, 3);    }    fclose( in);  }  if ( buf)    free( buf);  return;}/*******************************************************************************FUNCTION write_almanac()RETURNS  None.PARAMETERS None.PURPOSE  This function writes the broadcast almanac data to a file for later      use.  In particular to support a warm or hot start.WRITTEN BY  Clifford Kelley*******************************************************************************/void write_almanac( void){  int i;  out = fopen( "current.alm", "w+");  if ( !out)  {    printf( "write_almanac: error opening file 'current.alm'.\n");    exit(-1);  }  for (i=1;i<=32;i++)  {    if ( gps_alm[i].inc > 0.0)    {//******** Week  131 almanac for PRN-01 ********//ID:                         01//Health:                     000//Eccentricity:               0.5362033844E-002//Time of Applicability(s):  589824.0000//Orbital Inclination(rad):   0.9676266920//Rate of Right Ascen(r/s):  -0.8126052768E-008//SQRT(A)  (m 1/2):           5153.620605//Right Ascen at Week(rad):  -0.1178026838E+001//Argument of Perigee(rad):  -1.701721362//Mean Anom(rad):             0.2097295909E+001//Af0(s):                     0.2183914185E-003//Af1(s/s):                   0.3637978807E-011//week:                        131      fprintf( out, "******** Week %4d almanac for PRN-%02d ********\n",        gps_alm[i].week % 1024, i);      fprintf( out, "ID:                         %02d\n", i);      fprintf( out, "Health:                     %03d\n", gps_alm[i].health);      fprintf( out, "Eccentricity:               %10.9e\n", gps_alm[i].ety);      fprintf( out, "Time of Applicability(s):   %10.9e\n", gps_alm[i].toa);      fprintf( out, "Orbital Inclination(rad):   %10.9e\n", gps_alm[i].inc);      fprintf( out, "Rate of Right Ascen(R/s):   %10.9e\n", gps_alm[i].omegadot);      fprintf( out, "SQRT(A) (m^1/2):            %10.9e\n", gps_alm[i].sqra);      fprintf( out, "Right Ascen at TOA(rad):    %10.9e\n", gps_alm[i].omega0);      fprintf( out, "Argument of Perigee(rad):   %10.9e\n", gps_alm[i].w);      fprintf( out, "Mean Anom(rad):             %10.9e\n", gps_alm[i].ma);      fprintf( out, "Af0(s):                     %10.9e\n", gps_alm[i].af0);      fprintf( out, "Af1(s/s):                   %10.9e\n", gps_alm[i].af1);      fprintf( out, "week:                       %4d   \n", gps_alm[i].week % 1024);      fprintf( out, "\n");    }  }  fclose(out);}/*******************************************************************************FUNCTION write_ephemeris()RETURNS  None.PARAMETERS None.PURPOSE  This function writes the broadcast ephemeris data to a file for later  use.  In particular to support a hot start.WRITTEN BY  Clifford Kelley*******************************************************************************/void write_ephemeris(){  int i;  out = fopen( "current.eph", "w+");  if ( !out)  {    printf( "write_ephemeris: error opening file 'current.eph'\n");    exit(-1);  }  for ( i=1; i<=32; i++)  {    if ( gps_eph[i].inc0 >0.0)    {      fprintf( out, "**** Ephemeris for PRN-%02d ***********\n", i);      fprintf( out, "ID:                         %3d\n",    i);      fprintf( out, "Health:                     %3d\n",    gps_eph[i].health);      fprintf( out, "Week:                       %4d\n",    gps_eph[i].week);      fprintf( out, "E Time of Applic(s):        %10.9e\n", gps_eph[i].toe);      fprintf( out, "C Time of Applic(s):        %10.9e\n", gps_eph[i].toc);      fprintf( out, "Tgd(s):                     %10.9e\n", gps_eph[i].tgd);      fprintf( out, "Af0(s):                     %10.9e\n", gps_eph[i].af0);      fprintf( out, "Af1(s/s):                   %10.9e\n", gps_eph[i].af1);      fprintf( out, "Af2(s/s/s):                 %10.9e\n", gps_eph[i].af2);      fprintf( out, "Eccentricity:               %10.9e\n", gps_eph[i].ety);      fprintf( out, "Orbital Inclination(rad):   %10.9e\n", gps_eph[i].inc0);      fprintf( out, "Rate of Right Ascen(R/s):   %10.9e\n", gps_eph[i].omegadot);      fprintf( out, "SQRT(A) (m^1/2):            %10.9e\n", gps_eph[i].sqra);      fprintf( out, "Right Ascen at TOE(rad):    %10.9e\n", gps_eph[i].omega0);      fprintf( out, "Argument of Perigee(rad):   %10.9e\n", gps_eph[i].w);      fprintf( out, "Mean Anom(rad):             %10.9e\n", gps_eph[i].ma);      fprintf( out, "Cuc(rad):                   %10.9e\n", gps_eph[i].cuc);      fprintf( out, "Cus(rad):                   %10.9e\n", gps_eph[i].cus);      fprintf( out, "Crc(m):                     %10.9e\n", gps_eph[i].crc);      fprintf( out, "Crs(m):                     %10.9e\n", gps_eph[i].crs);      fprintf( out, "Cic(rad):                   %10.9e\n", gps_eph[i].cic);      fprintf( out, "Cis(rad):                   %10.9e\n", gps_eph[i].cis);      fprintf( out, "\n");    }  }  fclose(out);}/*******************************************************************************FUNCTION write_ion_utc()RETURNS  None.PARAMETERS None.PURPOSE  This function writes the broadcast ionospheric correction data and the      parameters to tie GPS time to UTC to a file for later use.WRITTEN BY  Clifford Kelley*******************************************************************************/void write_ion_utc(){  FILE *out;  out = fopen( "ion_utc.dat", "w+");  if ( !out)  {    printf( "write_ion_utc: error opening file 'ion_utc.dat'\n");    exit(-1);  }  fprintf( out, "al0:                        %e\n", Iono.al0);  fprintf( out, "al1:                        %e\n", Iono.al1);  fprintf( out, "al2:                        %e\n", Iono.al2);  fprintf( out, "al3:                        %e\n", Iono.al3);  fprintf( out, "b0:                         %f\n", Iono.b0);  fprintf( out, "b1:                         %f\n", Iono.b1);  fprintf( out, "b2:                         %f\n", Iono.b2);  fprintf( out, "b3:                         %f\n", Iono.b3);  fprintf( out, "a0:                         %f\n", Utc.a0);  fprintf( out, "a1:                         %f\n", Utc.a1);  fprintf( out, "dtls:                       %f\n", Utc.dtls);  fprintf( out, "tot:                        %f\n", Utc.tot);  fprintf( out, "WNt:                        %f\n", Utc.WNt);  fprintf( out, "WNlsf:                      %f\n", Utc.WNlsf);  fprintf( out, "DN:                         %f\n", Utc.DN);  fprintf( out, "dtlsf:                      %f\n", Utc.dtlsf);  fclose( out);  return;}/*******************************************************************************FUNCTION fix_sqrt( long x)RETURNS  long integerPARAMETERS      x long integerPURPOSE  This function finds the fixed point square root of a long integerWRITTEN BY  Clifford Kelley*******************************************************************************/long fix_sqrt( long x){  long xt, scr;  int i;// --- take care of sqrt(0) --- (G.B. 02.04.08)  if ( !x)    return (0);  i  = 0;  xt = x;  do  {    xt = xt >> 1;    i++;  } while( xt>0);  i  = (i >> 1) + 1;  xt = x >> i;  do  {     scr = xt * xt;     scr = x - scr;     scr = scr >> 1;     scr = scr / xt;