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Code Issues Releases Wiki Activity

Minor changes

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This commit is contained in:
Antonio Ramos 2018-04-12 17:01:07 +02:00
parent f92dd4dc83
commit ad220dd279
1 changed files with 19 additions and 12 deletions
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29
src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_cc.cc
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@ -172,7 +172,7 @@ int gps_l1_ca_telemetry_decoder_cc::general_work(int noutput_items __attribute__
unsigned int required_symbols = GPS_CA_PREAMBLE_LENGTH_SYMBOLS; unsigned int required_symbols = GPS_CA_PREAMBLE_LENGTH_SYMBOLS;
d_flag_preamble = false; d_flag_preamble = false;
if (d_symbol_history.size() > required_symbols and d_make_correlation) if ((d_symbol_history.size() > required_symbols) and (d_make_correlation or !d_flag_frame_sync))
{ {
//******* preamble correlation ******** //******* preamble correlation ********
for (unsigned int i = 0; i < GPS_CA_PREAMBLE_LENGTH_SYMBOLS; i++) for (unsigned int i = 0; i < GPS_CA_PREAMBLE_LENGTH_SYMBOLS; i++)
@ -181,24 +181,22 @@ int gps_l1_ca_telemetry_decoder_cc::general_work(int noutput_items __attribute__
{ {
if (d_symbol_history.at(i).Prompt_I < 0) // symbols clipping if (d_symbol_history.at(i).Prompt_I < 0) // symbols clipping
{ {
corr_value -= d_preambles_symbols[i] * d_symbol_history.at(i).correlation_length_ms; corr_value -= d_preambles_symbols[i];
} }
else else
{ {
corr_value += d_preambles_symbols[i] * d_symbol_history.at(i).correlation_length_ms; corr_value += d_preambles_symbols[i];
} }
} }
if (corr_value >= GPS_CA_PREAMBLE_LENGTH_SYMBOLS) }
if (std::abs(corr_value) >= GPS_CA_PREAMBLE_LENGTH_SYMBOLS)
{ {
d_symbol_counter_corr = 0; d_symbol_counter_corr++;
d_make_correlation = false;
break;
}
} }
} }
//******* frame sync ****************** //******* frame sync ******************
if (abs(corr_value) == GPS_CA_PREAMBLE_LENGTH_SYMBOLS) if (std::abs(corr_value) == GPS_CA_PREAMBLE_LENGTH_SYMBOLS)
{ {
//TODO: Rewrite with state machine //TODO: Rewrite with state machine
if (d_stat == 0) if (d_stat == 0)
@ -215,12 +213,14 @@ int gps_l1_ca_telemetry_decoder_cc::general_work(int noutput_items __attribute__
} }
else if (d_stat == 1) //check 6 seconds of preamble separation else if (d_stat == 1) //check 6 seconds of preamble separation
{ {
preamble_diff_ms = round(((static_cast<double>(d_symbol_history.at(0).Tracking_sample_counter) - d_preamble_time_samples) / static_cast<double>(d_symbol_history.at(0).fs)) * 1000.0); preamble_diff_ms = std::round(((static_cast<double>(d_symbol_history.at(0).Tracking_sample_counter) - d_preamble_time_samples) / static_cast<double>(d_symbol_history.at(0).fs)) * 1000.0);
if (abs(preamble_diff_ms - GPS_SUBFRAME_MS) < 1) if (std::abs(preamble_diff_ms - GPS_SUBFRAME_MS) < 1)
{ {
DLOG(INFO) << "Preamble confirmation for SAT " << this->d_satellite; DLOG(INFO) << "Preamble confirmation for SAT " << this->d_satellite;
d_GPS_FSM.Event_gps_word_preamble(); d_GPS_FSM.Event_gps_word_preamble();
d_flag_preamble = true; d_flag_preamble = true;
d_make_correlation = false;
d_symbol_counter_corr = 0;
d_preamble_time_samples = d_symbol_history.at(0).Tracking_sample_counter; // record the PRN start sample index associated to the preamble d_preamble_time_samples = d_symbol_history.at(0).Tracking_sample_counter; // record the PRN start sample index associated to the preamble
if (!d_flag_frame_sync) if (!d_flag_frame_sync)
{ {
@ -245,6 +245,11 @@ int gps_l1_ca_telemetry_decoder_cc::general_work(int noutput_items __attribute__
} }
else else
{ {
d_symbol_counter_corr++;
if (d_symbol_counter_corr > (GPS_SUBFRAME_MS - GPS_CA_TELEMETRY_SYMBOLS_PER_BIT))
{
d_make_correlation = true;
}
if (d_stat == 1) if (d_stat == 1)
{ {
preamble_diff_ms = round(((static_cast<double>(d_symbol_history.at(0).Tracking_sample_counter) - static_cast<double>(d_preamble_time_samples)) / static_cast<double>(d_symbol_history.at(0).fs)) * 1000.0); preamble_diff_ms = round(((static_cast<double>(d_symbol_history.at(0).Tracking_sample_counter) - static_cast<double>(d_preamble_time_samples)) / static_cast<double>(d_symbol_history.at(0).fs)) * 1000.0);
@ -254,6 +259,8 @@ int gps_l1_ca_telemetry_decoder_cc::general_work(int noutput_items __attribute__
d_stat = 0; //lost of frame sync d_stat = 0; //lost of frame sync
d_flag_frame_sync = false; d_flag_frame_sync = false;
flag_TOW_set = false; flag_TOW_set = false;
d_make_correlation = true;
d_symbol_counter_corr = 0;
} }
} }
} }