/* satellite position and clock with sbas correction -------------------------*/
static int satpos_sbas(gtime_t time, gtime_t teph, int sat, const nav_t *nav,
double *rs, double *dts, double *var, int *svh)
{
const sbssatp_t *sbs;
int i;
trace(4,"satpos_sbas: time=%s sat=%2d\n",time_str(time,3),sat);
/* search sbas satellite correciton */
for (i=0;i<nav->sbssat.nsat;i++) {
sbs=nav->sbssat.sat+i;
if (sbs->sat==sat) break;
}
if (i>=nav->sbssat.nsat) {
trace(2,"no sbas correction for orbit: %s sat=%2d\n",time_str(time,0),sat);
ephpos(time,teph,sat,nav,-1,rs,dts,var,svh);
*svh=-1;
return 0;
}
/* satellite postion and clock by broadcast ephemeris */
if (!ephpos(time,teph,sat,nav,sbs->lcorr.iode,rs,dts,var,svh)) return 0;
/* sbas satellite correction (long term and fast) */
if (sbssatcorr(time,sat,nav,rs,dts,var)) return 1;
*svh=-1;
return 0;
}
/* satellite position and clock ------------------------------------------------
* compute satellite position, velocity and clock
* args : gtime_t time I time (gpst)
* gtime_t teph I time to select ephemeris (gpst)
* int sat I satellite number
* nav_t *nav I navigation data
* int ephopt I ephemeris option (EPHOPT_???)
* double *rs O sat position and velocity (ecef)
* {x,y,z,vx,vy,vz} (m|m/s)
* double *dts O sat clock {bias,drift} (s|s/s)
* double *var O sat position and clock error variance (m^2)
* int *svh O sat health flag (-1:correction not available)
* return : status (1:ok,0:error)
* notes : satellite position is referenced to antenna phase center
* satellite clock does not include code bias correction (tgd or bgd)
*-----------------------------------------------------------------------------*/
extern int satpos(gtime_t time, gtime_t teph, int sat,
const nav_t *nav, double *rs, double *dts, double *var,
int *svh,char **msg)
{
*svh=0;
return ephpos(time,teph,sat,nav,-1,rs,dts,var,svh,msg);
// return 1;
}
/* satellite position and clock ------------------------------------------------
* compute satellite position, velocity and clock
* args : gtime_t time I time (gpst)
* gtime_t teph I time to select ephemeris (gpst)
* int sat I satellite number
* nav_t *nav I navigation data
* int ephopt I ephemeris option (EPHOPT_???)
* double *rs O sat position and velocity (ecef)
* {x,y,z,vx,vy,vz} (m|m/s)
* double *dts O sat clock {bias,drift} (s|s/s)
* double *var O sat position and clock error variance (m^2)
* int *svh O sat health flag (-1:correction not available)
* return : status (1:ok,0:error)
* notes : satellite position is referenced to antenna phase center
* satellite clock does not include code bias correction (tgd or bgd)
*-----------------------------------------------------------------------------*/
extern int satpos(gtime_t time, gtime_t teph, int sat, int ephopt,
const nav_t *nav, double *rs, double *dts, double *var,
int *svh)
{
trace(4,"satpos : time=%s sat=%2d ephopt=%d\n",time_str(time,3),sat,ephopt);
*svh=0;
switch (ephopt) {
case EPHOPT_BRDC : return ephpos (time,teph,sat,nav,-1,rs,dts,var,svh);
case EPHOPT_SBAS : return satpos_sbas(time,teph,sat,nav, rs,dts,var,svh);
case EPHOPT_SSRAPC: return satpos_ssr (time,teph,sat,nav, 0,rs,dts,var,svh);
case EPHOPT_SSRCOM: return satpos_ssr (time,teph,sat,nav, 1,rs,dts,var,svh);
case EPHOPT_PREC :
if (!peph2pos(time,sat,nav,1,rs,dts,var)) break; else return 1;
case EPHOPT_LEX :
if (!lexeph2pos(time,sat,nav,rs,dts,var)) break; else return 1;
}
*svh=-1;
return 0;
}
/* satellite position and clock with ssr correction --------------------------*/
static int satpos_ssr(gtime_t time, gtime_t teph, int sat, const nav_t *nav,
int opt, double *rs, double *dts, double *var, int *svh)
{
const ssr_t *ssr;
eph_t *eph;
double t1,t2,t3,er[3],ea[3],ec[3],rc[3],deph[3],dclk,dant[3]={0},tk;
int i,sys;
trace(4,"satpos_ssr: time=%s sat=%2d\n",time_str(time,3),sat);
ssr=nav->ssr+sat-1;
if (!ssr->t0[0].time) {
trace(2,"no ssr orbit correction: %s sat=%2d\n",time_str(time,0),sat);
return 0;
}
if (!ssr->t0[1].time) {
trace(2,"no ssr clock correction: %s sat=%2d\n",time_str(time,0),sat);
return 0;
}
/* inconsistency between orbit and clock correction */
if (ssr->iod[0]!=ssr->iod[1]) {
trace(2,"inconsist ssr correction: %s sat=%2d iod=%d %d\n",
time_str(time,0),sat,ssr->iod[0],ssr->iod[1]);
*svh=-1;
return 0;
}
t1=timediff(time,ssr->t0[0]);
t2=timediff(time,ssr->t0[1]);
t3=timediff(time,ssr->t0[2]);
/* ssr orbit and clock correction (ref [4]) */
if (fabs(t1)>MAXAGESSR||fabs(t2)>MAXAGESSR) {
trace(2,"age of ssr error: %s sat=%2d t=%.0f %.0f\n",time_str(time,0),
sat,t1,t2);
*svh=-1;
return 0;
}
if (ssr->udi[0]>=1.0) t1-=ssr->udi[0]/2.0;
if (ssr->udi[1]>=1.0) t2-=ssr->udi[0]/2.0;
for (i=0;i<3;i++) deph[i]=ssr->deph[i]+ssr->ddeph[i]*t1;
dclk=ssr->dclk[0]+ssr->dclk[1]*t2+ssr->dclk[2]*t2*t2;
/* ssr highrate clock correction (ref [4]) */
if (ssr->iod[0]==ssr->iod[2]&&ssr->t0[2].time&&fabs(t3)<MAXAGESSR_HRCLK) {
dclk+=ssr->hrclk;
}
if (norm(deph,3)>MAXECORSSR||fabs(dclk)>MAXCCORSSR) {
trace(3,"invalid ssr correction: %s deph=%.1f dclk=%.1f\n",
time_str(time,0),norm(deph,3),dclk);
*svh=-1;
return 0;
}
/* satellite postion and clock by broadcast ephemeris */
if (!ephpos(time,teph,sat,nav,ssr->iode,rs,dts,var,svh)) return 0;
/* satellite clock for gps, galileo and qzss */
sys=satsys(sat,NULL);
if (sys==SYS_GPS||sys==SYS_GAL||sys==SYS_QZS||sys==SYS_CMP) {
if (!(eph=seleph(teph,sat,ssr->iode,nav))) return 0;
/* satellite clock by clock parameters */
tk=timediff(time,eph->toc);
dts[0]=eph->f0+eph->f1*tk+eph->f2*tk*tk;
dts[1]=eph->f1+2.0*eph->f2*tk;
/* relativity correction */
dts[0]-=2.0*dot(rs,rs+3,3)/CLIGHT/CLIGHT;
}
/* radial-along-cross directions in ecef */
if (!normv3(rs+3,ea)) return 0;
cross3(rs,rs+3,rc);
if (!normv3(rc,ec)) {
*svh=-1;
return 0;
}
cross3(ea,ec,er);
/* satellite antenna offset correction */
if (opt) {
satantoff(time,rs,sat,nav,dant);
}
for (i=0;i<3;i++) {
rs[i]+=-(er[i]*deph[0]+ea[i]*deph[1]+ec[i]*deph[2])+dant[i];
}
/* t_corr = t_sv - (dts(brdc) + dclk(ssr) / CLIGHT) (ref [10] eq.3.12-7) */
dts[0]+=dclk/CLIGHT;
/* variance by ssr ura */
*var=var_urassr(ssr->ura);
trace(5,"satpos_ssr: %s sat=%2d deph=%6.3f %6.3f %6.3f er=%6.3f %6.3f %6.3f dclk=%6.3f var=%6.3f\n",
time_str(time,2),sat,deph[0],deph[1],deph[2],er[0],er[1],er[2],dclk,*var);
return 1;
}