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tropmodel, rtkpos: use the precise mapping function #524

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tropmodel, rtkpos: use the precise mapping function #524

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47 changes: 26 additions & 21 deletions src/rtkcmn.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3677,35 +3677,40 @@ extern int seliflc(int optnf,int sys)
/* use L1/L5 for Galileo if L5 is enabled */
return((optnf==2||sys!=SYS_GAL)?1:2);
}
/* troposphere model -----------------------------------------------------------
* compute tropospheric delay by standard atmosphere and saastamoinen model
* args : gtime_t time I time

/* Troposphere model -----------------------------------------------------------
* Compute tropospheric delay by standard atmosphere and saastamoinen model
* Args : gtime_t time I time
* double *pos I receiver position {lat,lon,h} (rad,m)
* double *azel I azimuth/elevation angle {az,el} (rad)
* double humi I relative humidity
* return : tropospheric delay (m)
*-----------------------------------------------------------------------------*/
extern double tropmodel(gtime_t time, const double *pos, const double *azel,
double humi)
{
const double temp0=15.0; /* temperature at sea level */
double hgt,pres,temp,e,z,trph,trpw;
* Return : tropospheric delay (m)
*----------------------------------------------------------------------------*/
extern double tropmodel(gtime_t time, const double *pos, const double *azel, double humi) {
const double temp0 = 15.0; // Temperature at sea level

if (pos[2]<-100.0||1E4<pos[2]||azel[1]<=0) return 0.0;
if (pos[2] < -100.0 || 1E4 < pos[2] || azel[1] <= 0) return 0.0;

/* standard atmosphere */
hgt=pos[2]<0.0?0.0:pos[2];
// Standard atmosphere
double hgt = pos[2] < 0.0 ? 0.0 : pos[2];

pres=1013.25*pow(1.0-2.2557E-5*hgt,5.2568);
temp=temp0-6.5E-3*hgt+273.16;
e=6.108*humi*exp((17.15*temp-4684.0)/(temp-38.45));
double temp = temp0 - 6.5E-3 * hgt + 273.16;
double pres = 1013.25 * pow(288.15 / temp, -5.255877);
double e = 6.108 * humi * exp((17.15 * temp - 4684.0) / (temp - 38.45));

/* saastamoinen model */
z=PI/2.0-azel[1];
trph=0.0022768*pres/(1.0-0.00266*cos(2.0*pos[0])-0.00028*hgt/1E3)/cos(z);
trpw=0.002277*(1255.0/temp+0.05)*e/cos(z);
return trph+trpw;
// Saastamoinen model
double z = PI / 2.0 - azel[1];
double trpzh = 0.0022768 * pres / (1.0 - 0.00266 * cos(2.0 * pos[0]) - 0.00028 * hgt / 1E3);
double trpzw = 0.002277 * (1255.0 / temp + 0.05) * e;

// Fast exit path.
if (fabs(z) < 1e-10) return trpzh + trpzw;

// Precise mapping function
double mapfw, mapfh = tropmapf(time, pos, azel, &mapfw);
return trpzh * mapfh + trpzw * mapfw;
}

#ifndef IERS_MODEL

static double interpc(const double coef[], double lat)
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21 changes: 15 additions & 6 deletions src/rtkpos.c
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,7 @@
#define STD_PREC_VAR_THRESH 0 /* pos variance threshold to skip standard precision */
/* solution: 0 = run every epoch, */
/* 0.5 = skip except for first*/
#define REL_HUMI 0.7 /* Relative humidity for Saastamoinen model */

/* constants/macros ----------------------------------------------------------*/

Expand Down Expand Up @@ -1020,7 +1021,7 @@ static int zdres(int base, const obsd_t *obs, int n, const double *rs,
double *y, double *e, double *azel, double *freq)
{
double r,rr_[3],pos[3],dant[NFREQ]={0},disp[3];
double mapfh,zhd,zazel[]={0.0,90.0*D2R};
double mapfh,zazel[]={0.0,90.0*D2R};
int i,nf=NF(opt);

trace(3,"zdres : n=%d rr=%.2f %.2f %.2f\n",n,rr[0], rr[1], rr[2]);
Expand Down Expand Up @@ -1054,17 +1055,25 @@ static int zdres(int base, const obsd_t *obs, int n, const double *rs,
/* adjust range for satellite clock-bias */
r+=-CLIGHT*dts[i*2];

/* adjust range for troposphere delay model (hydrostatic) */
zhd=tropmodel(obs[0].time,pos,zazel,0.0);
mapfh=tropmapf(obs[i].time,pos,azel+i*2,NULL);
r+=mapfh*zhd;
/* Adjust range for troposphere delay model */
double dtrp = 0.0;
if (opt->tropopt <= TROPOPT_SAAS) {
dtrp = tropmodel(obs[0].time, pos, azel + i * 2, REL_HUMI);
} else if (opt->tropopt == TROPOPT_SBAS) {
double vart;
dtrp = sbstropcorr(obs[0].time, pos, azel + i * 2, &vart);
} else if (opt->tropopt >= TROPOPT_EST) {
// Hydrostatic only
dtrp = tropmodel(obs[0].time, pos, azel + i * 2, 0.0);
}
r += dtrp;
trace(4, "sat=%d r=%.6f c*dts=%.6f dtrp=%.6f\n", obs[i].sat, r, CLIGHT * dts[i * 2], dtrp);

/* calc receiver antenna phase center correction */
antmodel(opt->pcvr+base,opt->antdel[base],azel+i*2,opt->posopt[1],
dant);

/* calc undifferenced phase/code residual for satellite */
trace(4,"sat=%d r=%.6f c*dts=%.6f zhd=%.6f map=%.6f\n",obs[i].sat,r,CLIGHT*dts[i*2],zhd,mapfh);
zdres_sat(base,r,obs+i,nav,azel+i*2,dant,opt,y+i*nf*2,freq+i*nf);
}
trace(4,"rr_=%.3f %.3f %.3f\n",rr_[0],rr_[1],rr_[2]);
Expand Down