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Float carrier phase for RTK simulation

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This commit is contained in:
OSQZSS 2017-12-02 11:29:04 +09:00
parent 398274a309
commit e467402a87
2 changed files with 28 additions and 6 deletions
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28
gpssim.c
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@ -1618,9 +1618,12 @@ int allocateChannel(channel_t *chan, ephem_t *eph, ionoutc_t ionoutc, gpstime_t
r_ref = rho.range;
phase_ini = (2.0*r_ref - r_xyz)/LAMBDA_L1;
#ifdef FLOAT_CARR_PHASE
chan[i].carr_phase = phase_ini - floor(phase_ini);
#else
phase_ini -= floor(phase_ini);
chan[i].carr_phase = (unsigned int)(512 * 65536.0 * phase_ini);
chan[i].carr_phase = (unsigned int)(512.0 * 65536.0 * phase_ini);
#endif
// Done.
break;
}
@ -2153,8 +2156,9 @@ int main(int argc, char *argv[])
// Update code phase and data bit counters
computeCodePhase(&chan[i], rho, 0.1);
chan[i].carr_phasestep = (int)(512 * 65536.0 * chan[i].f_carr * delt);
#ifndef FLOAT_CARR_PHASE
chan[i].carr_phasestep = (int)round(512.0 * 65536.0 * chan[i].f_carr * delt);
#endif
// Path loss
path_loss = 20200000.0/rho.d;
@ -2176,8 +2180,11 @@ int main(int argc, char *argv[])
{
if (chan[i].prn>0)
{
iTable = (chan[i].carr_phase >> 16) & 511;
#ifdef FLOAT_CARR_PHASE
iTable = (int)floor(chan[i].carr_phase*512.0);
#else
iTable = (chan[i].carr_phase >> 16) & 0x1ff; // 9-bit index
#endif
ip = chan[i].dataBit * chan[i].codeCA * cosTable512[iTable] * gain[i];
qp = chan[i].dataBit * chan[i].codeCA * sinTable512[iTable] * gain[i];
@ -2218,7 +2225,16 @@ int main(int argc, char *argv[])
chan[i].codeCA = chan[i].ca[(int)chan[i].code_phase]*2-1;
// Update carrier phase
#ifdef FLOAT_CARR_PHASE
chan[i].carr_phase += chan[i].f_carr * delt;
if (chan[i].carr_phase >= 1.0)
chan[i].carr_phase -= 1.0;
else if (chan[i].carr_phase<0.0)
chan[i].carr_phase += 1.0;
#else
chan[i].carr_phase += chan[i].carr_phasestep;
#endif
}
}

6
gpssim.h
View File

@ -1,6 +1,8 @@
#ifndef GPSSIM_H
#define GPSSIM_H
#define FLOAT_CARR_PHASE // For RKT simulation. Higher computational load, but smoother carrier phase.
#define TRUE (1)
#define FALSE (0)
@ -159,8 +161,12 @@ typedef struct
int ca[CA_SEQ_LEN]; /*< C/A Sequence */
double f_carr; /*< Carrier frequency */
double f_code; /*< Code frequency */
#ifdef FLOAT_CARR_PHASE
double carr_phase;
#else
unsigned int carr_phase; /*< Carrier phase */
int carr_phasestep; /*< Carrier phasestep */
#endif
double code_phase; /*< Code phase */
gpstime_t g0; /*!< GPS time at start */
unsigned long sbf[5][N_DWRD_SBF]; /*!< current subframe */