/* ************************************************************************    *                                                                      *   *                          GPS Simulation                              *   *                                                                      *   * -------------------------------------------------------------------- *   *                                                                      *   *    Module:   ogsxmit.cpp                                             *   *                                                                      *   *   Version:   0.1                                                     *   *                                                                      *   *      Date:   17.02.02                                                *   *                                                                      *   *    Author:   G. Beyerle                                              *   *                                                                      *   * -------------------------------------------------------------------- *   *                                                                      *   * Copyright (C) 2002-2006 Georg Beyerle                                *   *                                                                      *   * This program is free software; you can redistribute it and/or modify *   * it under the terms of the GNU General Public License as published by *   * the Free Software Foundation; either version 2 of the License, or    *   * (at your option) any later version.                                  *   *                                                                      *   * This program is distributed in the hope that it will be useful,      *   * but WITHOUT ANY WARRANTY; without even the implied warranty of       *   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *   * GNU General Public License for more details.                         *   *                                                                      *   * You should have received a copy of the GNU General Public License    *   * along with this program; if not, write to the Free Software          *   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.            *   *                                                                      *   * -------------------------------------------------------------------- *   *                                                                      *   * The files 'gpsfuncs.cpp', 'gpsrcvr.cpp' and 'gp2021.cpp' are modi-   *   * fied versions of the files with the same name from Clifford Kelley's *    * OpenSourceGPS distribution. The unmodified files can be obtained     *   * from http://www.home.earthlink.net/~cwkelley                         *   *                                                                      *   * -------------------------------------------------------------------- *   *                                                                      *   *                       GPS signal transmitter                         *   *                                                                      *   ************************************************************************ *//* ******************************* changes ********************************   dd.mm.yy -   ************************************************************************ */// to do:// - fill struct iono_data und struct UTC_data   / 17.2.02// - parity bits// - check calc of parity in parity_check()/* ------------------------------- includes ------------------------------- */#include <stdio.h>#include <stdlib.h>#include <math.h>#include <string.h>#include <time.h>#include <assert.h>#include "ogsdefine.h"#include "ogsstructs.h"#include "ogsprototypes.h"#include "ogslibrary.h"#include "boxmuller.h"#define MAIN#include "ogsextern.h"#undef MAIN/* ------------------------------- defines -------------------------------- *///#define XMTRBUFLEN 500000#define XMTRBUFLEN 150000//#define XMTRBUFLEN 1000/* ------------------------------- structs -------------------------------- */typedef struct{   int    active,          inhibited;    int    prn;                    // satellite id   long   carrier_cycle_counter;  // # of positive going zero crossings of i_lo   long   code_phase_counter;   long   carrier_dco_incr,   // 26 bit, frq res. is 42.57475 mHz          carrier_dco_phase,  // carrier cycle fraction / phase in 2pi/1024 increments          code_dco_phase,          code_dco_incr;   int    epoch_counter,          epoch_1ms,          // 0,...,19; 1 msec (1 C/A) code epoch          epoch_20ms;         // 0,...,49; 20 msec (20 C/A, 1 data bit) epoch} XMTRINFO;XMTRINFO XmtrInfo[NOFSAT+1];/* ------------------------------- globals -------------------------------- *///static double const SampleFrq = 5.714e6;//static double const CarrierFrq = 1.405396825e6;//static double const CodeFrq    = 1.023e6;static double SampleTime = 0;char *NavFrame[NOFSAT+1];static int HalfChip_Counter[NOFSAT+1];//  phase countersstatic unsigned long Carrier_Cycle[NOFSAT+1],                     Code_Cycle[NOFSAT+1],                     CACode_Counter[NOFSAT+1];   // 0,...,20*1500-1static double Carrier_DCO_Cycle[NOFSAT+1];//static int Carrier_DCO_I[] = {-1,1,2, 2, 1,-1,-2,-2};static int Carrier_DCO_I[] = {2, 2, 1, -1, -2, -2, -1, 1};static unsigned char XmtrBuf[XMTRBUFLEN];static char *NavBit[NOFSAT+1];static float QuantThresh,     // quantization theshold             Noise_dB,        // noise added to signal             Noise_Ampl,      // noise added to signal             MaxTime;static float Latitude, Longitude;  // receiver locationchar ProgramName[] = "ogsxmit";static char Version[] = "0.1.1";extern char *OutputFileName;extern char *NavFilePattern;extern int OverWrite;extern long CounterStartValue;/* -------------------------- prototypen (global) ------------------------- */void getargs( int argc, char *argv[]);/* ------------------------------ procedures ------------------------------ */void usage( void){  printf( "usage: %s [options]\n", ProgramName);  printf( "version %s (compiled %s %s) \n", Version, __DATE__, __TIME__);  printf( " options:\n");  printf( "   -h        : print this message                           \n");  printf( "   -v        : verbose                                      \n");  printf( "   -f        : overwrite existing files                     \n");  printf( "   -n <pat>  : navigation file pattern <pat>                \n");  printf( "   -o <file> : write data to  'data/'<file>  ['ogsraw.dat'] \n");  exit(0);}void check_options( void){  if ( !NavFilePattern)  {    printf( "No navigation file selected (option -n).");    exit(-1);  }  return;}////  read parameters from file//  adapted from read_rcvr_par()  (c) Clifford Kelley//static void read_xmit_par( void){  char infile[] = "xmit_par.dat", *tmpstr;  FILE *in;  tmpstr = conmalloc( strlen( OGSBinDir) + strlen( infile) + 1);  strcpy( tmpstr, OGSBinDir);  strcat( tmpstr, infile);  if (( in = fopen( tmpstr, "rt")) == NULL)  {    printf( "Error opening parameter file '%s'.\n", tmpstr);    perror( NULL);    exit( 0);  }  else  {#define SPSIZE 200    int loop = 1, ret;    char buf[SPSIZE];    char sep[] = ":";  /* list of token separators */    char *token;                 printf( "Read parameter from file '%s' ...\n", tmpstr);    while ( !feof( in) && loop)    {      fgets( buf, SPSIZE, in);      if ( buf[0] == '#')        continue;      token = strtok( buf, sep);   // format is  <keyword> : <value>      if ( token)      {        ret = read_key_value_pair_float( token, "Quantiz. Threshold", &QuantThresh, sep);        if ( !ret)          ret = read_key_value_pair_float( token, "Noise [dB]", &Noise_dB, sep);        if ( !ret)          ret = read_key_value_pair_float( token, "Max. Time [sec]", &MaxTime, sep);        if ( !ret)          ret = read_key_value_pair_float( token, "latitude [deg]", &Latitude, sep);        if ( !ret)          ret = read_key_value_pair_float( token, "longitude [deg]", &Longitude, sep);        if ( !ret)        {          token = strtok( NULL, sep);          if ( token)          {            printf( "unkown keyword >%s< in file %s\n", buf, tmpstr);            exit( -1);          }          }      }       else// --- token is NULL ---              loop = 0;    } // --- while ( !feof( in) && loop) ---  }  fclose( in);  if ( Verbose)  {    printf( "Finished reading parameter file %s.\n", tmpstr);    printf( "Press ENTER\n");    getchar();  }    if ( tmpstr)    free( tmpstr);  return;}////  initialize carrier and code counter increments//static void init_struct_xmitter( void){  int i;    for ( i=1; i<=NOFSAT; i++)  {    XmtrInfo[i].carrier_dco_incr = 0x1f7b1b9L;      // 33010105 * 42.57475 mHz = 1405396.968 Hz    XmtrInfo[i].code_dco_incr    = 0x16ea4a8L;      // 24028328 * 42.57475 mHz = 1023000.058 Hz//  start nav message at bit position CounterStartValue (out of 1500)    CACode_Counter[i] = 20 * CounterStartValue;  }    return;}////  calculate GPS C/A signal//static int calc_raw_sgn( void){  int i, j, cidx, didx, nidx, prn;  int sgn = 0;  int savsgn;  short int ca_prompt;  char navbit;  float sgnflt;  char d;//  float tmp, savtmp;//  nofprn = 0;    for ( prn=1; prn<=NOFSAT; prn++)  {    if ( NavBit[prn])    {////  increment carrier and code cycle counter//      Carrier_Cycle[prn] += XmtrInfo[prn].carrier_dco_incr;      Code_Cycle[prn]    += XmtrInfo[prn].code_dco_incr;//      printf(" Carrier_Cycle[%d] = %d\n", prn, Carrier_Cycle[prn]);//      printf(" Code_Cycle[%d]    = %d\n", prn, Code_Cycle[prn]);        ////  carrier DCO: 2^27 = 0x8000000 corresponds to 1 carrier cycle (1.4 MHz)//      if ( Carrier_Cycle[prn] & (0x1 << 27))      {        Carrier_Cycle[prn] &= ~(0x1f << 27);   // clear top 5 bits        XmtrInfo[prn].carrier_cycle_counter += 1;       }////  code DCO: 2^26 = 0x4000000 corresponds to 1/2 chip (2*1.023 MHz)//            2^27 = 0x8000000 corresponds to 1 chip (1.023 MHz)//      if ( Code_Cycle[prn] & (0x1 << 26))      {        Code_Cycle[prn] &= ~(0x3f << 26);   // clear top 6 bits        HalfChip_Counter[prn] += 1;      }      if ( HalfChip_Counter[prn] == 2046)      {        HalfChip_Counter[prn] = 0;        CACode_Counter[prn] += 1;//        printf("CACode_Counter[%d] = %d\n", prn, CACode_Counter[prn]);//        getchar();      }// wrap around after 1 frame (5 subframes, 5x300 bits)      CACode_Counter[prn] = CACode_Counter[prn] % (20*NAVMSGLEN);  ////  index in sin/cos look-up table (8-phase)//      cidx = (Carrier_Cycle[prn] >> 24) & 0x7;