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/*------------------------------------------------------------------------------
* simobs.c : observation data simulator
*
* Copyright (C) 2009 by T.TAKASU, All rights reserved.
*
* version : $Revision: 1.1 $ $Date: 2008/07/17 21:55:16 $
* history : 2009/03/23 1.0 new
*-----------------------------------------------------------------------------*/
#include "rtklib.h"
static const char rcsid[]="$Id:$";
#define PROGNAME "SIMOBS" /* program name */
/* simulation parameters -----------------------------------------------------*/
static double minel =5.0; /* minimum elevation angle (deg) */
static double slipthres =35.0; /* slip threashold (dBHz) */
static double errion =0.005; /* ionosphere error (m/10km) */
static double erreph =1.2; /* ephemeris error (m) */
static double errcp1 =0.002; /* carrier-phase meas error (m) */
static double errcp2 =0.002; /* carrier-phase meas error/sin(el) (m) */
static double errpr1 =0.2; /* pseudorange error (m) */
static double errpr2 =0.2; /* pseudorange error/sin(el) (m) */
static int gpsblock[]={ /* gps block flag (1:block IIF) */
1,1,1,1,1, 0,0,0,0,0, 0,0,0,0,0, 0,0,0,0,0,
0,0,0,0,0, 0,0,0,0,0, 0,0
};
/* generate random number with normal distribution ---------------------------*/
static double randn(double myu, double sig)
{
double a,b;
a=((double)rand()+1.0)/((double)RAND_MAX+1.0); /* 0<a<=1 */
b=((double)rand()+1.0)/((double)RAND_MAX+1.0); /* 0<b<=1 */
return myu+sqrt(-2.0*log(a))*sin(2.0*PI*b)*sig;
}
/* generate snr --------------------------------------------------------------*/
static void snrmodel(const double *azel, double *snr)
{
/* snr and snr deviation pattern (dbHz) by elevation (5 deg interval) */
double snrs[]={40,42,44,45,46,47,48,49,49,50,50,51,51,51,51,51,51,51,51};
double sdvs[]={ 3, 3, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
double loss[]={ 0, 3, 0, 3};
int i,j;
for (i=0;i<NFREQ;i++) {
j=(int)(azel[1]*R2D/5.0);
if (snr[i]==0.0) {
snr[i]=snrs[j]+randn(0.0,sdvs[j])-loss[i];
}
else {
snr[i]=0.5*snr[i]+0.5*(snrs[j]+randn(0.0,sdvs[j])-loss[i]);
}
}
}
/* generate error ------------------------------------------------------------*/
static void errmodel(const double *azel, double *snr, double *ecp, double *epr)
{
int i;
double ec,ep;
for (i=0;i<NFREQ;i++) {
ec=randn(0.0,errcp1)+randn(0.0,errcp2)/sin(azel[1]);
ep=randn(0.0,errpr1)+randn(0.0,errpr2)/sin(azel[1]);
ecp[i]=0.5*ecp[i]+0.5*ec; /* filter */
epr[i]=0.5*epr[i]+0.5*ep; /* filter */
}
}
/* generate simulated observation data ---------------------------------------*/
static int simobs(gtime_t ts, gtime_t te, double tint, const double *rr,
nav_t *nav, obs_t *obs, int opt)
{
gtime_t time;
obsd_t data[MAXSAT]={{{0}}};
double pos[3],rs[3*MAXSAT],dts[MAXSAT],r,e[3],azel[2];
double ecp[MAXSAT][NFREQ]={{0}},epr[MAXSAT][NFREQ]={{0}};
double snr[MAXSAT][NFREQ]={{0}},ers[MAXSAT][3]={{0}};
double iono,trop,fact,cp,pr,dtr=0.0,rref[3],bl;
int i,j,k,n,ns,amb[MAXSAT][NFREQ]={{0}},sys,prn;
char s[64];
double pref[]={36.106114294,140.087190410,70.3010}; /* ref station */
trace(3,"simobs:nnav=%d ngnav=%d\n",nav->n,nav->ng);
for (i=0;i<2;i++) pref[i]*=D2R;
pos2ecef(pref,rref);
for (i=0;i<3;i++) rref[i]-=rr[i];
bl=norm(rref,3)/1E4; /* baseline (10km) */
srand(0);
/* ephemeris error */
for (i=0;i<MAXSAT;i++) {
data[i].sat=i+1;
data[i].P[0]=2E7;
for (j=0;j<3;j++) ers[i][j]=randn(0.0,erreph);
}
srand(tickget());
ecef2pos(rr,pos);
n=(int)(timediff(te,ts)/tint+1.0);
for (i=0;i<n;i++) {
time=timeadd(ts,tint*i);
time2str(time,s,0);
for (j=0;j<MAXSAT;j++) data[j].time=time;
for (j=0;j<3;j++) { /* iteration for pseudorange */
satpos(time,data,MAXSAT,nav,rs,dts);
for (k=0;k<MAXSAT;k++) {
if ((r=geodist(rs+k*3,rr,e))<=0.0) continue;
data[k].P[0]=r+CLIGHT*(dtr-dts[k]);
}
}
satpos(time,data,MAXSAT,nav,rs,dts);
for (j=ns=0;j<MAXSAT;j++) {
/* add ephemeris error */
for (k=0;k<3;k++) rs[k+j*3]+=ers[j][k];
if ((r=geodist(rs+j*3,rr,e))<=0.0) continue;
satazel(pos,e,azel);
if (azel[1]<minel*D2R) continue;
iono=ionmodel(time,nav->ion,pos,azel);
trop=tropmodel(pos,azel,0.3);
/* add ionospheric error */
iono+=errion*bl*ionmapf(pos,azel);
snrmodel(azel,snr[j]);
errmodel(azel,snr[j],ecp[j],epr[j]);
sys=satsys(data[j].sat,&prn);
for (k=0;k<NFREQ;k++) {
data[j].L[k]=data[j].P[k]=0.0;
data[j].SNR[k]=0;
data[j].LLI[k]=0;
if (sys==SYS_GPS) {
if (k>=3) continue; /* no L5a/L5b in gps */
if (k>=2&&!gpsblock[prn-1]) continue; /* no L5 in block II */
}
else if (sys==SYS_GLO) {
if (k>=3) continue;
}
else if (sys==SYS_GAL) {
if (k==1) continue; /* no L2 in galileo */
}
else continue;
/* generate observation data */
fact=lam[k]*lam[k]/lam[0]/lam[0];
cp=r+CLIGHT*(dtr-dts[j])-fact*iono+trop+ecp[j][k];
pr=r+CLIGHT*(dtr-dts[j])+fact*iono+trop+epr[j][k];
if (amb[j][k]==0) amb[j][k]=(int)(-cp/lam[k]);
data[j].L[k]=cp/lam[k]+amb[j][k];
data[j].P[k]=pr;
data[j].SNR[k]=(unsigned char)snr[j][k];
data[j].LLI[k]=data[j].SNR[k]<slipthres?1:0;
}
if (obs->nmax<=obs->n) {
if (obs->nmax==0) obs->nmax=65532; else obs->nmax+=65532;
if (!(obs->data=(obsd_t *)realloc(obs->data,sizeof(obsd_t)*obs->nmax))) {
fprintf(stderr,"malloc error\n");
return 0;
}
}
obs->data[obs->n++]=data[j];
ns++;
}
fprintf(stderr,"time=%s nsat=%2d\r",s,ns);
}
fprintf(stderr,"\n");
return 1;
}
/* simgal main ---------------------------------------------------------------*/
int main(int argc, char **argv)
{
FILE *fp;
rnxopt_t rnxopt={{0}};
obs_t obs={0};
nav_t nav={0};
gtime_t ts={0},te={0};
double es[]={2000,1,1,0,0,0},ee[]={2000,1,1,0,0,0},tint=30.0;
double pos[3]={0},rr[3];
char *infile[16]={0},*outfile="";
int i,j,n=0,opt=0;
for (i=1;i<argc;i++) {
if (!strcmp(argv[i],"-o")&&i+1<argc) outfile=argv[++i];
else if (!strcmp(argv[i],"-ts")&&i+1<argc) {
sscanf(argv[++i],"%lf/%lf/%lf %lf:%lf:%lf",es,es+1,es+2,es+3,es+4,es+5);
ts=epoch2time(es);
}
else if (!strcmp(argv[i],"-te")&&i+1<argc) {
sscanf(argv[++i],"%lf/%lf/%lf %lf:%lf:%lf",ee,ee+1,ee+2,ee+3,ee+4,ee+5);
te=epoch2time(ee);
}
else if (!strcmp(argv[i],"-ti")&&i+1<argc) tint=atof(argv[++i]);
else if (!strcmp(argv[i],"-r")&&i+3<argc) {
for (j=0;j<3;j++) pos[j]=atof(argv[++i]); /* lat,lon,hgt */
}
else infile[n++]=argv[i];
}
if (n<=0) {
fprintf(stderr,"no input file\n");
return -1;
}
if (!*outfile) {
fprintf(stderr,"no output file\n");
return -1;
}
if (norm(pos,3)<=0.0) {
fprintf(stderr,"no receiver pos\n");
return -1;
}
pos[0]*=D2R; pos[1]*=D2R; pos2ecef(pos,rr);
/* read simulated/real rinex nav files */
readrnx(infile,n,&obs,&nav);
if (nav.n<=0) {
fprintf(stderr,"no nav data\n");
return -1;
}
/* generate simulated observation data */
if (!simobs(ts,te,tint,rr,&nav,&obs,opt)) return -1;
/* output rinex obs file */
if (!(fp=fopen(outfile,"w"))) {
fprintf(stderr,"error : outfile open %s\n",outfile);
return -1;
}
fprintf(stderr,"saving...: %s\n",outfile);
strcpy(rnxopt.prog,PROGNAME);
strcpy(rnxopt.comment[0],"SIMULATED OBS DATA");
rnxopt.tstart=ts;
rnxopt.tstart=te;
rnxopt.navsys=SYS_ALL;
rnxopt.obstype=OBSTYPE_PR|OBSTYPE_CP|OBSTYPE_SNR;
rnxopt.freqtype=FREQTYPE_L1|FREQTYPE_L2|FREQTYPE_L5|FREQTYPE_L7;
for (i=0;i<3;i++) rnxopt.apppos[i]=rr[i];
outrnxobsh(fp,&rnxopt);
for (i=0;i<obs.n;i=j) {
for (j=i;j<obs.n;j++) {
if (timediff(obs.data[j].time,obs.data[i].time)>0.001) break;
}
outrnxobsb(fp,&rnxopt,obs.data+i,j-i,0);
}
fclose(fp);
return 0;
}
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