mirror of
https://github.com/gnss-sdr/gnss-sdr
synced 2025-10-31 15:23:04 +00:00
Improving tracking stability of carrier lock detector
This commit is contained in:
Javier Arribas
@@ -444,6 +444,7 @@ dll_pll_veml_tracking::dll_pll_veml_tracking(const Dll_Pll_Conf &conf_) : gr::bl
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d_carrier_lock_test = 1.0;
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d_CN0_SNV_dB_Hz = 0.0;
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d_carrier_lock_fail_counter = 0;
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d_code_lock_fail_counter = 0;
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d_carrier_lock_threshold = trk_parameters.carrier_lock_th;
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d_Prompt_Data = static_cast<gr_complex *>(volk_gnsssdr_malloc(sizeof(gr_complex), volk_gnsssdr_get_alignment()));
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d_cn0_smoother = Exponential_Smoother();
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@@ -451,6 +452,13 @@ dll_pll_veml_tracking::dll_pll_veml_tracking(const Dll_Pll_Conf &conf_) : gr::bl
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{
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d_cn0_smoother.set_samples_for_initialization(200 / static_cast<int>(d_code_period * 1000.0));
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}
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d_carrier_lock_test_smoother = Exponential_Smoother();
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d_carrier_lock_test_smoother.set_alpha(0.002);
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d_carrier_lock_test_smoother.set_min_value(-1.0);
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d_carrier_lock_test_smoother.set_offset(0.0);
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d_carrier_lock_test_smoother.set_samples_for_initialization(25);
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d_acquisition_gnss_synchro = nullptr;
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d_channel = 0;
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d_acq_code_phase_samples = 0.0;
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@@ -717,6 +725,7 @@ void dll_pll_veml_tracking::start_tracking()
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std::fill_n(d_correlator_outs, d_n_correlator_taps, gr_complex(0.0, 0.0));
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d_carrier_lock_fail_counter = 0;
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d_code_lock_fail_counter = 0;
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d_rem_code_phase_samples = 0.0;
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d_rem_carr_phase_rad = 0.0;
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d_rem_code_phase_chips = 0.0;
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@@ -866,11 +875,13 @@ bool dll_pll_veml_tracking::cn0_and_tracking_lock_status(double coh_integration_
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float d_CN0_SNV_dB_Hz_raw = cn0_svn_estimator(d_Prompt_buffer, trk_parameters.cn0_samples, static_cast<float>(coh_integration_time_s));
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d_CN0_SNV_dB_Hz = d_cn0_smoother.smooth(d_CN0_SNV_dB_Hz_raw);
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// Carrier lock indicator
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d_carrier_lock_test = carrier_lock_detector(d_Prompt_buffer, trk_parameters.cn0_samples);
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d_carrier_lock_test = d_carrier_lock_test_smoother.smooth(carrier_lock_detector(d_Prompt_buffer, 1));
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//d_carrier_lock_test = carrier_lock_detector(d_Prompt_buffer, trk_parameters.cn0_samples);
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// Loss of lock detection
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if (!d_pull_in_transitory)
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{
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if (d_carrier_lock_test < d_carrier_lock_threshold or d_CN0_SNV_dB_Hz < trk_parameters.cn0_min)
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//d_carrier_lock_test < d_carrier_lock_threshold or
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if (d_carrier_lock_test < d_carrier_lock_threshold)
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{
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d_carrier_lock_fail_counter++;
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}
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@@ -881,13 +892,28 @@ bool dll_pll_veml_tracking::cn0_and_tracking_lock_status(double coh_integration_
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d_carrier_lock_fail_counter--;
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}
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}
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if (d_CN0_SNV_dB_Hz < trk_parameters.cn0_min)
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{
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d_code_lock_fail_counter++;
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}
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else
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{
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if (d_code_lock_fail_counter > 0)
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{
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d_code_lock_fail_counter--;
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}
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}
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}
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if (d_carrier_lock_fail_counter > trk_parameters.max_lock_fail)
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if (d_carrier_lock_fail_counter > trk_parameters.max_carrier_lock_fail or d_code_lock_fail_counter > trk_parameters.max_code_lock_fail)
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{
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std::cout << "Loss of lock in channel " << d_channel << "!" << std::endl;
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LOG(INFO) << "Loss of lock in channel " << d_channel << "!";
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LOG(INFO) << "Loss of lock in channel " << d_channel
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<< " (carrier_lock_fail_counter:" << d_carrier_lock_fail_counter
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<< " code_lock_fail_counter : " << d_code_lock_fail_counter << ")";
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this->message_port_pub(pmt::mp("events"), pmt::from_long(3)); // 3 -> loss of lock
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d_carrier_lock_fail_counter = 0;
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d_code_lock_fail_counter = 0;
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return false;
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}
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return true;
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@@ -1573,6 +1599,8 @@ int dll_pll_veml_tracking::general_work(int noutput_items __attribute__((unused)
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if (trk_parameters.pull_in_time_s < (d_sample_counter - d_acq_sample_stamp) / static_cast<int>(trk_parameters.fs_in))
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{
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d_pull_in_transitory = false;
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d_carrier_lock_fail_counter = 0;
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d_code_lock_fail_counter = 0;
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}
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}
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switch (d_state)
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@@ -1606,6 +1634,7 @@ int dll_pll_veml_tracking::general_work(int noutput_items __attribute__((unused)
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d_state = 2;
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d_sample_counter += samples_offset; // count for the processed samples
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d_cn0_smoother.reset();
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d_carrier_lock_test_smoother.reset();
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DLOG(INFO) << "Number of samples between Acquisition and Tracking = " << acq_trk_diff_samples << " ( " << acq_trk_diff_seconds << " s)";
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DLOG(INFO) << "PULL-IN Doppler [Hz] = " << d_carrier_doppler_hz
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@@ -1642,51 +1671,59 @@ int dll_pll_veml_tracking::general_work(int noutput_items __attribute__((unused)
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// enable write dump file this cycle (valid DLL/PLL cycle)
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log_data(false);
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if (d_secondary)
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if (!d_pull_in_transitory)
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{
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// ####### SECONDARY CODE LOCK #####
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d_Prompt_circular_buffer.push_back(*d_Prompt);
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if (d_Prompt_circular_buffer.size() == d_secondary_code_length)
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if (d_secondary)
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{
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next_state = acquire_secondary();
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if (next_state)
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// ####### SECONDARY CODE LOCK #####
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d_Prompt_circular_buffer.push_back(*d_Prompt);
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if (d_Prompt_circular_buffer.size() == d_secondary_code_length)
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{
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LOG(INFO) << systemName << " " << signal_pretty_name << " secondary code locked in channel " << d_channel
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<< " for satellite " << Gnss_Satellite(systemName, d_acquisition_gnss_synchro->PRN) << std::endl;
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std::cout << systemName << " " << signal_pretty_name << " secondary code locked in channel " << d_channel
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<< " for satellite " << Gnss_Satellite(systemName, d_acquisition_gnss_synchro->PRN) << std::endl;
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}
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}
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}
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else if (d_symbols_per_bit > 1) //Signal does not have secondary code. Search a bit transition by sign change
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{
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float current_tracking_time_s = static_cast<float>(d_sample_counter - d_acq_sample_stamp) / trk_parameters.fs_in;
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if (current_tracking_time_s > 10)
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{
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d_symbol_history.push_back(d_Prompt->real());
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//******* preamble correlation ********
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int32_t corr_value = 0;
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if ((static_cast<int32_t>(d_symbol_history.size()) == d_preamble_length_symbols)) // and (d_make_correlation or !d_flag_frame_sync))
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{
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int i = 0;
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for (const auto &iter : d_symbol_history)
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next_state = acquire_secondary();
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if (next_state)
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{
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if (iter < 0.0) // symbols clipping
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{
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corr_value -= d_preambles_symbols[i];
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}
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else
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{
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corr_value += d_preambles_symbols[i];
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}
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i++;
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LOG(INFO) << systemName << " " << signal_pretty_name << " secondary code locked in channel " << d_channel
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<< " for satellite " << Gnss_Satellite(systemName, d_acquisition_gnss_synchro->PRN) << std::endl;
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std::cout << systemName << " " << signal_pretty_name << " secondary code locked in channel " << d_channel
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<< " for satellite " << Gnss_Satellite(systemName, d_acquisition_gnss_synchro->PRN) << std::endl;
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}
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}
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if (corr_value == d_preamble_length_symbols)
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}
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else if (d_symbols_per_bit > 1) //Signal does not have secondary code. Search a bit transition by sign change
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{
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float current_tracking_time_s = static_cast<float>(d_sample_counter - d_acq_sample_stamp) / trk_parameters.fs_in;
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if (current_tracking_time_s > 10)
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{
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LOG(INFO) << systemName << " " << signal_pretty_name << " tracking preamble detected in channel " << d_channel
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<< " for satellite " << Gnss_Satellite(systemName, d_acquisition_gnss_synchro->PRN) << std::endl;
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next_state = true;
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d_symbol_history.push_back(d_Prompt->real());
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//******* preamble correlation ********
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int32_t corr_value = 0;
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if ((static_cast<int32_t>(d_symbol_history.size()) == d_preamble_length_symbols)) // and (d_make_correlation or !d_flag_frame_sync))
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{
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int i = 0;
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for (const auto &iter : d_symbol_history)
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{
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if (iter < 0.0) // symbols clipping
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{
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corr_value -= d_preambles_symbols[i];
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}
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else
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{
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corr_value += d_preambles_symbols[i];
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}
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i++;
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}
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}
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if (corr_value == d_preamble_length_symbols)
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{
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LOG(INFO) << systemName << " " << signal_pretty_name << " tracking preamble detected in channel " << d_channel
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<< " for satellite " << Gnss_Satellite(systemName, d_acquisition_gnss_synchro->PRN) << std::endl;
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next_state = true;
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}
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else
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{
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next_state = false;
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}
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}
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else
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{
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@@ -1695,14 +1732,13 @@ int dll_pll_veml_tracking::general_work(int noutput_items __attribute__((unused)
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}
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else
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{
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next_state = false;
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next_state = true;
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}
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}
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else
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{
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next_state = true;
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next_state = false; //keep in state 2 during pull-in transitory
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}
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// ########### Output the tracking results to Telemetry block ##########
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if (interchange_iq)
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{
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@@ -1837,7 +1873,6 @@ int dll_pll_veml_tracking::general_work(int noutput_items __attribute__((unused)
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d_extend_correlation_symbols_count = 0;
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d_state = 4;
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}
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log_data(true);
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break;
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}
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case 4: // narrow tracking
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@@ -193,13 +193,14 @@ private:
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// CN0 estimation and lock detector
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int32_t d_cn0_estimation_counter;
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int32_t d_carrier_lock_fail_counter;
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int32_t d_code_lock_fail_counter;
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double d_carrier_lock_test;
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double d_CN0_SNV_dB_Hz;
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double d_carrier_lock_threshold;
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boost::circular_buffer<gr_complex> d_Prompt_circular_buffer;
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gr_complex *d_Prompt_buffer;
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Exponential_Smoother d_cn0_smoother;
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Exponential_Smoother d_carrier_lock_test_smoother;
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// file dump
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std::ofstream d_dump_file;
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std::string d_dump_filename;
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