caiyu/gps-sdr-sim
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Fixed satellite clock and earth rotation correctons

Browse Source
This commit is contained in:
OSQZSS 2015-07-20 10:15:08 +09:00
parent b182ac048e
commit d77ec10dcd
1 changed files with 15 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
gpssim.c
View File

@ -181,8 +181,8 @@ typedef struct
// Working variables follow // Working variables follow
double n; // Mean motion (Average angular velocity) double n; // Mean motion (Average angular velocity)
double sq1e2; // sqrt(1-e^2) double sq1e2; // sqrt(1-e^2)
double A; // A double A; // Semi-major axis
double omgkdot; // (OmegaDot-OmegaEdot) double omgkdot; // OmegaDot-OmegaEdot
} ephem_t; } ephem_t;
typedef struct typedef struct
@ -484,6 +484,14 @@ void satpos(ephem_t eph, gpstime_t g, double *pos, double *vel, double *clk)
vel[1] = eph.omgkdot*pos[0] + xpkdot*sok + tmp*cok; vel[1] = eph.omgkdot*pos[0] + xpkdot*sok + tmp*cok;
vel[2] = ypk*cik*ikdot + ypkdot*sik; vel[2] = ypk*cik*ikdot + ypkdot*sik;
// Satellite clock correction
tk = g.sec - eph.toc.sec;
if(tk>SECONDS_IN_HALF_WEEK)
tk -= SECONDS_IN_WEEK;
else if(tk<-SECONDS_IN_HALF_WEEK)
tk += SECONDS_IN_WEEK;
clk[0] = eph.af0 + tk*(eph.af1 + tk*eph.af2) + relativistic - eph.tgd; clk[0] = eph.af0 + tk*(eph.af1 + tk*eph.af2) + relativistic - eph.tgd;
clk[1] = eph.af1 + 2.0*tk*eph.af2; clk[1] = eph.af1 + 2.0*tk*eph.af2;
@ -980,6 +988,7 @@ void computeRange(range_t *rho, ephem_t eph, gpstime_t g, double xyz[])
double los[3]; double los[3];
double tau; double tau;
double range,rate; double range,rate;
double xrot,yrot;
// SV position at time of the pseudorange observation. // SV position at time of the pseudorange observation.
satpos(eph, g, pos, vel, clk); satpos(eph, g, pos, vel, clk);
@ -994,8 +1003,10 @@ void computeRange(range_t *rho, ephem_t eph, gpstime_t g, double xyz[])
pos[2] -= vel[2]*tau; pos[2] -= vel[2]*tau;
// Earth rotation correction. The change in velocity can be neglected. // Earth rotation correction. The change in velocity can be neglected.
pos[0] += pos[1]*OMEGA_EARTH*tau; xrot = pos[0] + pos[1]*OMEGA_EARTH*tau;
pos[1] -= pos[0]*OMEGA_EARTH*tau; yrot = pos[1] - pos[0]*OMEGA_EARTH*tau;
pos[0] = xrot;
pos[1] = yrot;
// New observer to satellite vector and satellite range. // New observer to satellite vector and satellite range.
subVect(los, pos, xyz); subVect(los, pos, xyz);