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

Add the path loss of each satellite

Browse Source
This commit is contained in:
OSQZSS 2015-12-20 12:33:06 +09:00
parent d8eab7ede7
commit e49404d983
1 changed files with 17 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
gpssim.c
View File

@ -78,10 +78,6 @@ typedef int bool;
#define SC08 (8) #define SC08 (8)
#define SC16 (16) #define SC16 (16)
#define ADC_GAIN (250) // for bladeRF txvga1 = -25dB with 50dB external attenuation
#define _SINE_LUT
#ifdef _SINE_LUT
int sinTable512[] = { int sinTable512[] = {
2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47, 2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47,
50, 53, 56, 59, 62, 65, 68, 71, 74, 77, 80, 83, 86, 89, 91, 94, 50, 53, 56, 59, 62, 65, 68, 71, 74, 77, 80, 83, 86, 89, 91, 94,
@ -151,7 +147,6 @@ int cosTable512[] = {
232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 241, 242, 243, 244, 244, 245, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 241, 242, 243, 244, 244, 245,
245, 246, 247, 247, 248, 248, 248, 249, 249, 249, 249, 250, 250, 250, 250, 250 245, 246, 247, 247, 248, 248, 248, 249, 249, 249, 249, 250, 250, 250, 250, 250
}; };
#endif
/*! \file gpssim.c /*! \file gpssim.c
* \brief GPS Satellite Simulator * \brief GPS Satellite Simulator
@ -215,6 +210,7 @@ typedef struct
gpstime_t g; gpstime_t g;
double range; double range;
double rate; double rate;
double d;
} range_t; } range_t;
/*! \brief Structure representing a Channel */ /*! \brief Structure representing a Channel */
@ -1121,6 +1117,7 @@ void computeRange(range_t *rho, ephem_t eph, gpstime_t g, double xyz[])
// New observer to satellite vector and satellite range. // New observer to satellite vector and satellite range.
subVect(los, pos, xyz); subVect(los, pos, xyz);
range = normVect(los); range = normVect(los);
rho->d = range;
// Pseudorange. // Pseudorange.
rho->range = range - SPEED_OF_LIGHT*clk[0]; rho->range = range - SPEED_OF_LIGHT*clk[0];
@ -1335,12 +1332,8 @@ int main(int argc, char *argv[])
unsigned long prevwrd; unsigned long prevwrd;
int nib; int nib;
#ifdef _SINE_LUT
int ip,qp; int ip,qp;
int iTable; int iTable;
#else
double ip,qp;
#endif
short *iq_buff = NULL; short *iq_buff = NULL;
signed char *iq8_buff = NULL; signed char *iq8_buff = NULL;
@ -1367,6 +1360,8 @@ int main(int argc, char *argv[])
int result; int result;
int gain[MAX_CHAN];
//////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////
// Read options // Read options
//////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////
@ -1558,7 +1553,7 @@ int main(int argc, char *argv[])
chan[nsat].prn = sv+1; chan[nsat].prn = sv+1;
nsat++; nsat++;
printf("%02d %6.1f %5.1f\n", sv+1, azel[0]*R2D, azel[1]*R2D); printf("%02d %6.1f %5.1f %10.1f\n", sv+1, azel[0]*R2D, azel[1]*R2D, normVect(los));
} }
} }
} }
@ -1571,6 +1566,7 @@ int main(int argc, char *argv[])
// Allocate I/Q buffer // Allocate I/Q buffer
iq_buff = calloc(2*iq_buff_size, 2); iq_buff = calloc(2*iq_buff_size, 2);
if (iq_buff==NULL) if (iq_buff==NULL)
{ {
printf("Faild to allocate IQ buffer.\n"); printf("Faild to allocate IQ buffer.\n");
@ -1710,6 +1706,11 @@ int main(int argc, char *argv[])
// Save current pseudorange // Save current pseudorange
rho0[sv] = rho; rho0[sv] = rho;
// Path loss
gain[i] = (int)(20200000.0*100.0/rho.d); // scaled by 100
// Receiver antenna gain
} }
for (isamp=0; isamp<iq_buff_size; isamp++) for (isamp=0; isamp<iq_buff_size; isamp++)
@ -1719,22 +1720,14 @@ int main(int argc, char *argv[])
for (i=0; i<nsat; i++) for (i=0; i<nsat; i++)
{ {
#ifdef _SINE_LUT
iTable = (chan[i].carr_phase >> 16) & 511; iTable = (chan[i].carr_phase >> 16) & 511;
ip = chan[i].dataBit * chan[i].codeCA * cosTable512[iTable]; ip = chan[i].dataBit * chan[i].codeCA * cosTable512[iTable] * gain[i];
qp = chan[i].dataBit * chan[i].codeCA * sinTable512[iTable]; qp = chan[i].dataBit * chan[i].codeCA * sinTable512[iTable] * gain[i];
i_acc += ip; i_acc += ip/100;
q_acc += qp; q_acc += qp/100;
#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);
// Store I/Q samples into buffer
chan[i].iq_buff[isamp*2] = (short)(ADC_GAIN*ip);
chan[i].iq_buff[isamp*2+1] = (short)(ADC_GAIN*qp);
#endif
// Update code phase // Update code phase
chan[i].code_phase += chan[i].f_code * delt; chan[i].code_phase += chan[i].f_code * delt;
@ -1768,7 +1761,7 @@ int main(int argc, char *argv[])
} }
// Store I/Q samples into buffer // Store I/Q samples into buffer
iq_buff[isamp*2] = (short)i_acc; iq_buff[isamp*2] = (short)i_acc;
iq_buff[isamp*2+1] = (short)q_acc; iq_buff[isamp*2+1] = (short)q_acc;
} // End of omp parallel for } // End of omp parallel for
@ -1776,15 +1769,12 @@ int main(int argc, char *argv[])
if (data_format==SC08) if (data_format==SC08)
{ {
for (isamp=0; isamp<2*iq_buff_size; isamp++) for (isamp=0; isamp<2*iq_buff_size; isamp++)
{
iq8_buff[isamp] = iq_buff[isamp]>>4; // 12-bit bladeRF -> 8-bit HackRF iq8_buff[isamp] = iq_buff[isamp]>>4; // 12-bit bladeRF -> 8-bit HackRF
}
fwrite(iq8_buff, 1, 2*iq_buff_size, fp); fwrite(iq8_buff, 1, 2*iq_buff_size, fp);
} }
else else
{
fwrite(iq_buff, 2, 2*iq_buff_size, fp); fwrite(iq_buff, 2, 2*iq_buff_size, fp);
}
// Update receiver time // Update receiver time
grx.sec += 0.1; grx.sec += 0.1;