/* decode navigation data (GPS/QZS L1CA subframe) ------------------------------
*
* args : uint8_t *buff I navigation data bits
* sdreph_t *eph I/O sdr ephemeris structure
* return : int subframe ID (1-5)
*-----------------------------------------------------------------------------*/
int decode_frame_l1ca(const uint8_t *buff, sdreph_t *eph)
{
int id=getbitu(buff,49,3); /* subframe ID */
switch (id) {
case 1: decode_subfrm1(buff,eph); break;
case 2: decode_subfrm2(buff,eph); break;
case 3: decode_subfrm3(buff,eph); break;
case 4: decode_subfrm4(buff,eph); break;
case 5: decode_subfrm5(buff,eph); break;
}
return id;
}
/* decode gps/qzss navigation data frame ---------------------------------------
* decode navigation data frame and extract ephemeris and ion/utc parameters
* args : unsigned char *buff I gps navigation data frame (without parity)
* buff[0-29]: 24 bits x 10 words
* eph_t *eph IO ephemeris message (NULL: no input)
* alm_t *alm IO almanac (NULL: no input)
* double *ion IO ionospheric parameters (NULL: no input)
* double *utc IO delta-utc parameters (NULL: no input)
* int *leaps IO leap seconds (s) (NULL: no input)
* return : status (0:no valid, 1-5:subframe id)
* notes : use cpu time to resolve modulo 1024 ambiguity of the week number
* see ref [1]
* utc[3] reference week for utc parameter is truncated in 8 bits
* ion and utc parameters by qzss indicate local iono and qzst-utc
* parameters.
*-----------------------------------------------------------------------------*/
extern int decode_frame(const unsigned char *buff, eph_t *eph, alm_t *alm,
double *ion, double *utc, int *leaps)
{
int id=getbitu(buff,43,3); /* subframe id */
trace(3,"decodefrm: id=%d\n",id);
switch (id) {
case 1: return decode_subfrm1(buff,eph);
case 2: return decode_subfrm2(buff,eph);
case 3: return decode_subfrm3(buff,eph);
case 4: return decode_subfrm4(buff,alm,ion,utc,leaps);
case 5: return decode_subfrm5(buff,alm,ion,utc,leaps);
}
return 0;
}