diff --git a/src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.cc b/src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.cc index 70eef4727..3cb599866 100755 --- a/src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.cc +++ b/src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.cc @@ -2,6 +2,7 @@ * \file dll_pll_veml_tracking.cc * \brief Implementation of a code DLL + carrier PLL tracking block. * \author Antonio Ramos, 2018 antonio.ramosdet(at)gmail.com + * Javier Arribas, 2018. jarribas(at)cttc.es * * Code DLL + carrier PLL according to the algorithms described in: * [1] K.Borre, D.M.Akos, N.Bertelsen, P.Rinder, and S.H.Jensen, @@ -84,10 +85,12 @@ dll_pll_veml_tracking::dll_pll_veml_tracking(const Dll_Pll_Conf &conf_) : gr::bl this->message_port_register_out(pmt::mp("events")); this->set_relative_rate(1.0 / static_cast(trk_parameters.vector_length)); + // Telemetry bit synchronization message port input (mainly for GPS L1 CA) + this->message_port_register_in(pmt::mp("preamble_samplestamp")); + // initialize internal vars d_veml = false; d_cloop = true; - d_synchonizing = false; d_code_chip_rate = 0.0; d_secondary_code_length = 0; d_secondary_code_string = nullptr; @@ -120,6 +123,30 @@ dll_pll_veml_tracking::dll_pll_veml_tracking(const Dll_Pll_Conf &conf_) : gr::bl d_secondary = false; trk_parameters.track_pilot = false; interchange_iq = false; + + // set the preamble + unsigned short int preambles_bits[GPS_CA_PREAMBLE_LENGTH_BITS] = GPS_PREAMBLE; + + // preamble bits to sampled symbols + d_gps_l1ca_preambles_symbols = static_cast(volk_gnsssdr_malloc(GPS_CA_PREAMBLE_LENGTH_SYMBOLS * sizeof(int), volk_gnsssdr_get_alignment())); + int n = 0; + for (int i = 0; i < GPS_CA_PREAMBLE_LENGTH_BITS; i++) + { + for (unsigned int j = 0; j < GPS_CA_TELEMETRY_SYMBOLS_PER_BIT; j++) + { + if (preambles_bits[i] == 1) + { + d_gps_l1ca_preambles_symbols[n] = 1; + } + else + { + d_gps_l1ca_preambles_symbols[n] = -1; + } + n++; + } + } + d_symbol_history.resize(GPS_CA_PREAMBLE_LENGTH_SYMBOLS); // Change fixed buffer size + d_symbol_history.clear(); // Clear all the elements in the buffer } else if (signal_type.compare("2S") == 0) { @@ -521,7 +548,6 @@ void dll_pll_veml_tracking::start_tracking() // enable tracking pull-in d_state = 1; - d_synchonizing = false; d_cloop = true; d_Prompt_buffer_deque.clear(); d_last_prompt = gr_complex(0.0, 0.0); @@ -533,6 +559,11 @@ void dll_pll_veml_tracking::start_tracking() dll_pll_veml_tracking::~dll_pll_veml_tracking() { + if (signal_type.compare("1C") == 0) + { + volk_gnsssdr_free(d_gps_l1ca_preambles_symbols); + } + if (d_dump_file.is_open()) { try @@ -1281,39 +1312,82 @@ int dll_pll_veml_tracking::general_work(int noutput_items __attribute__((unused) } else if (d_symbols_per_bit > 1) //Signal does not have secondary code. Search a bit transition by sign change { - if (d_synchonizing) + float current_tracking_time_s = static_cast(d_sample_counter - d_acq_sample_stamp) / trk_parameters.fs_in; + if (current_tracking_time_s > 10) { - if (d_Prompt->real() * d_last_prompt.real() > 0.0) + d_symbol_history.push_back(d_Prompt->real()); + //******* preamble correlation ******** + int corr_value = 0; + if ((d_symbol_history.size() == GPS_CA_PREAMBLE_LENGTH_SYMBOLS)) // and (d_make_correlation or !d_flag_frame_sync)) { - d_current_symbol++; + for (unsigned int i = 0; i < GPS_CA_PREAMBLE_LENGTH_SYMBOLS; i++) + { + if (d_symbol_history.at(i) < 0) // symbols clipping + { + corr_value -= d_gps_l1ca_preambles_symbols[i]; + } + else + { + corr_value += d_gps_l1ca_preambles_symbols[i]; + } + } } - else if (d_current_symbol > d_symbols_per_bit) + if (corr_value == GPS_CA_PREAMBLE_LENGTH_SYMBOLS) { - d_synchonizing = false; - d_current_symbol = 1; + //std::cout << "Preamble detected at tracking!" << std::endl; + next_state = true; } else { - d_current_symbol = 1; - d_last_prompt = *d_Prompt; + next_state = false; } } - else if (d_last_prompt.real() != 0.0) - { - d_current_symbol++; - if (d_current_symbol == d_symbols_per_bit) next_state = true; - } else { - d_last_prompt = *d_Prompt; - d_synchonizing = true; - d_current_symbol = 1; + next_state = false; } } else { next_state = true; } + + // ########### Output the tracking results to Telemetry block ########## + if (interchange_iq) + { + if (trk_parameters.track_pilot) + { + // Note that data and pilot components are in quadrature. I and Q are interchanged + current_synchro_data.Prompt_I = static_cast((*d_Prompt_Data).imag()); + current_synchro_data.Prompt_Q = static_cast((*d_Prompt_Data).real()); + } + else + { + current_synchro_data.Prompt_I = static_cast((*d_Prompt).imag()); + current_synchro_data.Prompt_Q = static_cast((*d_Prompt).real()); + } + } + else + { + if (trk_parameters.track_pilot) + { + // Note that data and pilot components are in quadrature. I and Q are interchanged + current_synchro_data.Prompt_I = static_cast((*d_Prompt_Data).real()); + current_synchro_data.Prompt_Q = static_cast((*d_Prompt_Data).imag()); + } + else + { + current_synchro_data.Prompt_I = static_cast((*d_Prompt).real()); + current_synchro_data.Prompt_Q = static_cast((*d_Prompt).imag()); + } + } + current_synchro_data.Code_phase_samples = d_rem_code_phase_samples; + current_synchro_data.Carrier_phase_rads = d_acc_carrier_phase_rad; + current_synchro_data.Carrier_Doppler_hz = d_carrier_doppler_hz; + current_synchro_data.CN0_dB_hz = d_CN0_SNV_dB_Hz; + current_synchro_data.Flag_valid_symbol_output = true; + current_synchro_data.correlation_length_ms = d_correlation_length_ms; + if (next_state) { // reset extended correlator d_VE_accu = gr_complex(0.0, 0.0); @@ -1324,7 +1398,6 @@ int dll_pll_veml_tracking::general_work(int noutput_items __attribute__((unused) d_last_prompt = gr_complex(0.0, 0.0); d_Prompt_buffer_deque.clear(); d_current_symbol = 0; - d_synchonizing = false; if (d_enable_extended_integration) { diff --git a/src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.h b/src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.h index 0437e8a35..b57bc2200 100755 --- a/src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.h +++ b/src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.h @@ -41,6 +41,7 @@ #include #include #include +#include class dll_pll_veml_tracking; @@ -69,6 +70,7 @@ private: friend dll_pll_veml_tracking_sptr dll_pll_veml_make_tracking(const Dll_Pll_Conf &conf_); dll_pll_veml_tracking(const Dll_Pll_Conf &conf_); + void msg_handler_preamble_index(pmt::pmt_t msg); bool cn0_and_tracking_lock_status(double coh_integration_time_s); bool acquire_secondary(); @@ -102,9 +104,12 @@ private: std::string *d_secondary_code_string; std::string signal_pretty_name; + uint64_t d_preamble_sample_counter; + int *d_gps_l1ca_preambles_symbols; + boost::circular_buffer d_symbol_history; + //tracking state machine int d_state; - bool d_synchonizing; //Integration period in samples int d_correlation_length_ms; int d_n_correlator_taps;