caiyu/gps-sdr-sim
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change loop order between satellite and samples

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omit iq_buff's on each channel
treat carr_phase as int
This commit is contained in:
TT 2015-11-28 03:48:24 +09:00
parent ccbb0baba0
commit 8f6b083057
1 changed files with 38 additions and 46 deletions
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84
gpssim.c
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@ -224,7 +224,8 @@ typedef struct
int ca[CA_SEQ_LEN]; /*< C/A Sequence */
double f_carr; /*< Carrier frequency */
double f_code; /*< Code frequency */
double carr_phase; /*< Carrier phase */
unsigned int carr_phase; /*< Carrier phase */
int carr_phasestep; /*< Carrier phasestep */
double code_phase; /*< Code phase */
gpstime_t g0; /*!< GPS time at start */
unsigned long dwrd[N_DWRD]; /*!< Data words of sub-frame */
@ -233,7 +234,6 @@ typedef struct
int icode; /*!< initial code */
int dataBit; /*!< current data bit */
int codeCA; /*!< current C/A code */
short *iq_buff; /*< buffer of I/Q samples */
} channel_t;
/* !\brief generate the C/A code sequence for a given Satellite Vehicle PRN
@ -1341,7 +1341,8 @@ int main(int argc, char *argv[])
#else
double ip,qp;
#endif
void *iq_buff = NULL;
short *iq_buff = NULL;
signed char *iq8_buff = NULL;
gpstime_t grx;
range_t rho0[MAX_SAT];
@ -1569,17 +1570,23 @@ int main(int argc, char *argv[])
////////////////////////////////////////////////////////////
// Allocate I/Q buffer
if (data_format==SC08)
iq_buff = (signed char *)calloc(2*iq_buff_size, 1);
else
iq_buff = (short *)calloc(2*iq_buff_size, 2);
iq_buff = calloc(2*iq_buff_size, 2);
if (iq_buff==NULL)
{
printf("Faild to allocate IQ buffer.\n");
exit(1);
}
if (data_format==SC08)
{
iq8_buff = calloc(2*iq_buff_size, 1);
if (iq8_buff==NULL)
{
printf("Faild to allocate IQ buffer.\n");
exit(1);
}
}
// Open output file
if (NULL==(fp=fopen(outfile,"wb")))
{
@ -1598,15 +1605,6 @@ int main(int argc, char *argv[])
{
// C/A code generation
codegen(chan[i].ca, chan[i].prn);
// Allocate I/Q buffer
chan[i].iq_buff = (short *)calloc(2*iq_buff_size, 2);
if (chan[i].iq_buff==NULL)
{
printf("Faild to allocate IQ buffer.\n");
exit(1);
}
}
// Initialize carrier phase
@ -1626,8 +1624,8 @@ int main(int argc, char *argv[])
r_xyz = tmp.range;
phase_ini = (2.0*r_ref - r_xyz)/LAMBDA_L1;
chan[i].carr_phase = phase_ini - floor(phase_ini);
phase_ini -= floor(phase_ini);
chan[i].carr_phase = 512 * 65536.0 * phase_ini;
}
////////////////////////////////////////////////////////////
@ -1710,21 +1708,27 @@ int main(int argc, char *argv[])
// Update code phase and data bit counters
computeCodePhase(&chan[i], rho0[sv], rho, 0.1);
chan[i].carr_phasestep = 512 * 65536.0 * chan[i].f_carr * delt;
// Save current pseudorange
rho0[sv] = rho;
}
for (isamp=0; isamp<iq_buff_size; isamp++)
{
for (isamp=0; isamp<iq_buff_size; isamp++)
{
int i_acc = 0;
int q_acc = 0;
for (i=0; i<nsat; i++)
{
#ifdef _SINE_LUT
iTable = (int)floor(chan[i].carr_phase*512.0);
iTable = (chan[i].carr_phase >> 16) & 511;
ip = chan[i].dataBit * chan[i].codeCA * cosTable512[iTable];
qp = chan[i].dataBit * chan[i].codeCA * sinTable512[iTable];
// Store I/Q samples into buffer
chan[i].iq_buff[isamp*2] = (short)ip;
chan[i].iq_buff[isamp*2+1] = (short)qp;
i_acc += ip;
q_acc += qp;
#else
ip = chan[i].dataBit * chan[i].codeCA * cos(2.0*PI*chan[i].carr_phase);
qp = chan[i].dataBit * chan[i].codeCA * sin(2.0*PI*chan[i].carr_phase);
@ -1762,35 +1766,25 @@ int main(int argc, char *argv[])
chan[i].codeCA = chan[i].ca[(int)chan[i].code_phase]*2-1;
// Update carrier 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;
chan[i].carr_phase += chan[i].carr_phasestep;
}
// Store I/Q samples into buffer
iq_buff[isamp*2] = (short)i_acc;
iq_buff[isamp*2+1] = (short)q_acc;
} // End of omp parallel for
if (data_format==SC08)
{
for (isamp=0; isamp<2*iq_buff_size; isamp++)
{
signed char sample = 0;
for (i=0; i<nsat; i++)
sample += (signed char)(chan[i].iq_buff[isamp]>>4); // 12-bit bladeRF -> 8-bit HackRF
((signed char*)iq_buff)[isamp] = sample;
iq8_buff[isamp] = iq_buff[isamp]>>4; // 12-bit bladeRF -> 8-bit HackRF
}
fwrite(iq_buff, 1, 2*iq_buff_size, fp);
fwrite(iq8_buff, 1, 2*iq_buff_size, fp);
}
else
{
for (isamp=0; isamp<2*iq_buff_size; isamp++)
{
short sample = 0;
for (i=0; i<nsat; i++)
sample += chan[i].iq_buff[isamp];
((short*)iq_buff)[isamp] = sample;
}
fwrite(iq_buff, 2, 2*iq_buff_size, fp);
}
@ -1808,8 +1802,6 @@ int main(int argc, char *argv[])
// Free I/Q buffer
free(iq_buff);
for (i=0; i<nsat; i++)
free(chan[i].iq_buff);
// Close file
fclose(fp);