/** Get correlations from a NAP tracking channel and store them in the
* tracking channel state struct.
* \param channel Tracking channel to read correlations for.
*/
void tracking_channel_get_corrs(u8 channel)
{
tracking_channel_t* chan = &tracking_channel[channel];
switch(chan->state)
{
case TRACKING_RUNNING:
/* Read early ([0]), prompt ([1]) and late ([2]) correlations. */
nap_track_corr_rd_blocking(channel, &chan->corr_sample_count, chan->cs);
break;
case TRACKING_DISABLED:
default:
/* TODO: WTF? */
break;
}
}
/** Read data from a NAP track channel's CORR register.
*
* \param channel NAP track channel whose CORR register to read.
* \param sample_count Number of sample clock cycles in correlation period.
* \param corrs Array of E,P,L correlations from correlation period.
*/
void nap_track_read_results(u8 channel,
u32* count_snapshot, corr_t corrs[],
double *code_phase_early,
double *carrier_phase)
{
struct nap_ch_state *s = &nap_ch_state[channel];
u32 sample_count;
nap_track_corr_rd_blocking(channel, &sample_count, corrs);
s->count_snapshot += sample_count;
s->code_phase += (u64)sample_count * s->code_pinc_prev;
s->carrier_phase += (s64)sample_count * s->carr_pinc_prev;
s->carr_pinc_prev = s->carr_pinc;
*count_snapshot = s->count_snapshot;
*code_phase_early = (double)s->code_phase /
NAP_TRACK_CODE_PHASE_UNITS_PER_CHIP;
*carrier_phase = (double)s->carrier_phase /
NAP_TRACK_CARRIER_PHASE_UNITS_PER_CYCLE;
}
