caiyu/gps-sdr-sim
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Introduce CA_SEQ_LEN as symbolic constant for 1023

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We don't need to distinguish int and double, as the int constant
will be converted to double before any comparison anyway.
This commit is contained in:
Harald Welte 2015-08-21 01:14:38 +02:00
parent 9081cad620
commit b269f1d187
1 changed files with 13 additions and 8 deletions
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21
gpssim.c
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@ -38,6 +38,9 @@ typedef int bool;
/*! \brief Number of words */
#define N_DWRD (N_SBF*N_DWRD_SBF) // 10 word per subframe
/*! \brief C/A code sequence length */
#define CA_SEQ_LEN (1023)
#define SECONDS_IN_WEEK 604800.0
#define SECONDS_IN_HALF_WEEK 302400.0
#define SECONDS_IN_DAY 86400.0
@ -218,7 +221,7 @@ typedef struct
typedef struct
{
int prn; /*< PRN Number */
int ca[1023]; /*< C/A Sequence */
int ca[CA_SEQ_LEN]; /*< C/A Sequence */
double f_carr; /*< Carrier frequency */
double f_code; /*< Code frequency */
double carr_phase; /*< Carrier phase */
@ -245,7 +248,9 @@ void codegen(int *ca, int prn)
473, 474, 509, 512, 513, 514, 515, 516, 859, 860,
861, 862};
int g1[1023], g2[1023], r1[N_DWRD_SBF], r2[N_DWRD_SBF], c1, c2;
int g1[CA_SEQ_LEN], g2[CA_SEQ_LEN];
int r1[N_DWRD_SBF], r2[N_DWRD_SBF];
int c1, c2;
int i,j;
if (prn<1 || prn>32)
@ -254,7 +259,7 @@ void codegen(int *ca, int prn)
for (i=0; i<N_DWRD_SBF; i++)
r1[i] = r2[i] = -1;
for (i=0; i<1023; i++)
for (i=0; i<CA_SEQ_LEN; i++)
{
g1[i] = r1[9];
g2[i] = r2[9];
@ -270,8 +275,8 @@ void codegen(int *ca, int prn)
r2[0] = c2;
}
for (i=0,j=1023-delay[prn-1]; i<1023; i++,j++)
ca[i] = (1-g1[i]*g2[j%1023])/2;
for (i=0,j=CA_SEQ_LEN-delay[prn-1]; i<CA_SEQ_LEN; i++,j++)
ca[i] = (1-g1[i]*g2[j%CA_SEQ_LEN])/2;
return;
}
@ -1154,7 +1159,7 @@ void computeCodePhase(channel_t *chan, range_t rho0, range_t rho1, double dt)
ms = (((rho0.g.sec-chan->g0.sec)+6.0) - rho0.range/SPEED_OF_LIGHT)*1000.0;
ims = (int)ms;
chan->code_phase = (ms-(double)ims)*1023.0; // in chip
chan->code_phase = (ms-(double)ims)*CA_SEQ_LEN; // in chip
chan->iword = ims/600; // 1 word = 30 bits = 600 ms
ims -= chan->iword*600;
@ -1633,9 +1638,9 @@ int main(int argc, char *argv[])
// Update code phase
chan[i].code_phase += chan[i].f_code * delt;
if (chan[i].code_phase>=1023.0)
if (chan[i].code_phase>=CA_SEQ_LEN)
{
chan[i].code_phase -= 1023.0;
chan[i].code_phase -= CA_SEQ_LEN;
chan[i].icode++;