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mirror of https://github.com/gnss-sdr/gnss-sdr synced 2024-12-12 19:20:32 +00:00

Removing unused code, improving ref satellite selection in observables and partial correction of the gps L2 TOW offset bug

This commit is contained in:
Javier Arribas 2017-03-30 19:25:46 +02:00
parent b745ebf0a8
commit e0b0605545
9 changed files with 436 additions and 441 deletions

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@ -268,12 +268,12 @@ Resampler2.implementation=Pass_Through
;######### CHANNELS GLOBAL CONFIG ############
;#count: Number of available GPS satellite channels.
Channels_1C.count=0
Channels_2S.count=13
Channels_2S.count=11
;#GPS.prns=7,8
;#in_acquisition: Number of channels simultaneously acquiring for the whole receiver
Channels.in_acquisition=12
Channels.in_acquisition=10
;# signal:
;# "1C" GPS L1 C/A
@ -293,7 +293,7 @@ Channel6.RF_channel_ID=1
Channel7.RF_channel_ID=1
Channel8.RF_channel_ID=1
Channel9.RF_channel_ID=1
Channel10.RF_channel_ID=1
Channel10.RF_channel_ID=0
Channel11.RF_channel_ID=1
Channel12.RF_channel_ID=0
Channel13.RF_channel_ID=1
@ -349,7 +349,7 @@ Tracking_1C.early_late_space_chips=0.5;
Tracking_2S.implementation=GPS_L2_M_DLL_PLL_Tracking
Tracking_2S.item_type=gr_complex
Tracking_2S.if=0
Tracking_2S.dump=false
Tracking_2S.dump=true
Tracking_2S.dump_filename=./tracking_ch_
Tracking_2S.pll_bw_hz=2.0;
Tracking_2S.dll_bw_hz=0.25;
@ -360,7 +360,7 @@ Tracking_2S.early_late_space_chips=0.5;
;######### TELEMETRY DECODER CONFIG ############
TelemetryDecoder_1C.implementation=GPS_L1_CA_Telemetry_Decoder
TelemetryDecoder_1C.dump=false
TelemetryDecoder_1C.decimation_factor=20;
TelemetryDecoder_1C.decimation_factor=1;
TelemetryDecoder_2S.implementation=GPS_L2C_Telemetry_Decoder
TelemetryDecoder_2S.dump=false
@ -372,7 +372,7 @@ TelemetryDecoder_2S.decimation_factor=1;
Observables.implementation=Hybrid_Observables
;#dump: Enable or disable the Observables internal binary data file logging [true] or [false]
Observables.dump=false
Observables.dump=true
;#dump_filename: Log path and filename.
Observables.dump_filename=./observables.dat

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@ -100,7 +100,14 @@ hybrid_observables_cc::~hybrid_observables_cc()
bool Hybrid_pairCompare_gnss_synchro_d_TOW_at_current_symbol(const std::pair<int,Gnss_Synchro>& a, const std::pair<int,Gnss_Synchro>& b)
{
return (a.second.d_TOW_at_current_symbol) < (b.second.d_TOW_at_current_symbol);
if (a.second.d_TOW_at_current_symbol==b.second.d_TOW_at_current_symbol)
{
return (a.second.Prn_timestamp_ms/1000.0) > (b.second.Prn_timestamp_ms/1000.0);
}else{
return (a.second.d_TOW_at_current_symbol) < (b.second.d_TOW_at_current_symbol);
}
}
@ -179,6 +186,7 @@ int hybrid_observables_cc::general_work (int noutput_items,
// what is the most recent symbol TOW in the current set? -> this will be the reference symbol
gnss_synchro_iter = max_element(current_gnss_synchro_map.begin(), current_gnss_synchro_map.end(), Hybrid_pairCompare_gnss_synchro_d_TOW_at_current_symbol);
double d_TOW_reference = gnss_synchro_iter->second.d_TOW_at_current_symbol;
//std::cout<<"OBS SV REF SAT: "<<gnss_synchro_iter->second.PRN<<std::endl;
double d_ref_PRN_rx_time_ms = gnss_synchro_iter->second.Prn_timestamp_ms;
// Now compute RX time differences due to the PRN alignment in the correlators
@ -196,6 +204,10 @@ int hybrid_observables_cc::general_work (int noutput_items,
+ GPS_STARTOFFSET_ms;
//convert to meters
pseudorange_m = traveltime_ms * GPS_C_m_ms; // [m]
//std::cout<<"["<<gnss_synchro_iter->second.PRN<<"] delta_rx_t: "<<delta_rx_time_ms
// <<" [ms] delta_TOW_ms: "<<(d_TOW_reference - gnss_synchro_iter->second.d_TOW_at_current_symbol) * 1000.0
// <<" Pr: "<<pseudorange_m<<" [m]"
// <<std::endl;
// update the pseudorange object
current_gnss_synchro[gnss_synchro_iter->second.Channel_ID] = gnss_synchro_iter->second;
current_gnss_synchro[gnss_synchro_iter->second.Channel_ID].Pseudorange_m = pseudorange_m;
@ -246,6 +258,8 @@ int hybrid_observables_cc::general_work (int noutput_items,
double tmp_double;
for (unsigned int i = 0; i < d_nchannels; i++)
{
tmp_double = current_gnss_synchro[i].RX_time;
d_dump_file.write((char*)&tmp_double, sizeof(double));
tmp_double = current_gnss_synchro[i].d_TOW_at_current_symbol;
d_dump_file.write((char*)&tmp_double, sizeof(double));
tmp_double = current_gnss_synchro[i].Carrier_Doppler_hz;

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@ -154,22 +154,19 @@ int gps_l2c_telemetry_decoder_cc::general_work (int noutput_items __attribute__(
//* delay by the formulae:
//* \code
//* symbolTime_ms = msg->tow * 6000 + *pdelay * 20
d_TOW_at_current_symbol=((double)msg.tow) * 6.0 + ((double)delay) * GPS_L2_M_PERIOD +GPS_L2_M_PERIOD;
current_synchro_data.d_TOW_at_current_symbol = d_TOW_at_current_symbol;
current_synchro_data.Prn_timestamp_ms = in[0].Tracking_timestamp_secs * 1000.0;
d_TOW_at_current_symbol=((double)msg.tow) * 6.0 + ((double)delay) * GPS_L2_M_PERIOD +12*GPS_L2_M_PERIOD;
d_flag_valid_word=true;
}
else
{
d_TOW_at_current_symbol +=GPS_L2_M_PERIOD;
current_synchro_data.d_TOW_at_current_symbol = d_TOW_at_current_symbol;
current_synchro_data.Prn_timestamp_ms = in[0].Tracking_timestamp_secs * 1000.0;
if (current_synchro_data.Flag_valid_symbol_output==false)
{
d_flag_valid_word=false;
}
}
current_synchro_data.d_TOW_at_current_symbol = d_TOW_at_current_symbol;
current_synchro_data.Prn_timestamp_ms = in[0].Tracking_timestamp_secs * 1000.0;
current_synchro_data.Flag_valid_word=d_flag_valid_word;
// if (flag_PLL_180_deg_phase_locked == true)

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@ -539,7 +539,6 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items __attri
current_synchro_data.Prompt_Q = static_cast<double>((d_correlator_outs[1]).imag());
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample (Hybridization OK!)
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + d_correlation_length_samples + d_rem_code_phase_samples) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
current_synchro_data.Carrier_phase_rads = GPS_TWO_PI * d_acc_carrier_phase_cycles;
current_synchro_data.Carrier_Doppler_hz = d_carrier_doppler_hz;
current_synchro_data.CN0_dB_hz = d_CN0_SNV_dB_Hz;
@ -559,7 +558,6 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items __attri
current_synchro_data.Prompt_Q = static_cast<double>((d_correlator_outs[1]).imag());
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample (Hybridization OK!)
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + d_correlation_length_samples + d_rem_code_phase_samples) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
current_synchro_data.Carrier_phase_rads = GPS_TWO_PI * d_acc_carrier_phase_cycles;
current_synchro_data.Carrier_Doppler_hz = d_carrier_doppler_hz;// todo: project the carrier doppler
current_synchro_data.CN0_dB_hz = d_CN0_SNV_dB_Hz;
@ -574,7 +572,6 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items __attri
current_synchro_data.System = {'G'};
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + d_correlation_length_samples + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
}
//assign the GNURadio block output data
*out[0] = current_synchro_data;

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@ -534,7 +534,6 @@ int gps_l1_ca_dll_pll_c_aid_tracking_fpga_sc::general_work (int noutput_items __
current_synchro_data.Prompt_Q = static_cast<double>((d_correlator_outs_16sc[1]).imag());
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample (Hybridization OK!)
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + d_correlation_length_samples + d_rem_code_phase_samples) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
current_synchro_data.Carrier_phase_rads = GPS_TWO_PI * d_acc_carrier_phase_cycles;
current_synchro_data.Carrier_Doppler_hz = d_carrier_doppler_hz;
current_synchro_data.CN0_dB_hz = d_CN0_SNV_dB_Hz;
@ -554,7 +553,6 @@ int gps_l1_ca_dll_pll_c_aid_tracking_fpga_sc::general_work (int noutput_items __
current_synchro_data.Prompt_Q = static_cast<double>((d_correlator_outs_16sc[1]).imag());
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample (Hybridization OK!)
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + d_correlation_length_samples + d_rem_code_phase_samples) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
current_synchro_data.Carrier_phase_rads = GPS_TWO_PI * d_acc_carrier_phase_cycles;
current_synchro_data.Carrier_Doppler_hz = d_carrier_doppler_hz;// todo: project the carrier doppler
current_synchro_data.CN0_dB_hz = d_CN0_SNV_dB_Hz;
@ -569,7 +567,6 @@ int gps_l1_ca_dll_pll_c_aid_tracking_fpga_sc::general_work (int noutput_items __
current_synchro_data.System = {'G'};
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + d_correlation_length_samples + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
}
*out[0] = current_synchro_data;
if(d_dump)

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@ -542,7 +542,6 @@ int gps_l1_ca_dll_pll_c_aid_tracking_sc::general_work (int noutput_items __attri
current_synchro_data.Prompt_Q = static_cast<double>((d_correlator_outs_16sc[1]).imag());
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample (Hybridization OK!)
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + d_correlation_length_samples + d_rem_code_phase_samples) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
current_synchro_data.Carrier_phase_rads = GPS_TWO_PI * d_acc_carrier_phase_cycles;
current_synchro_data.Carrier_Doppler_hz = d_carrier_doppler_hz;
current_synchro_data.CN0_dB_hz = d_CN0_SNV_dB_Hz;
@ -562,7 +561,6 @@ int gps_l1_ca_dll_pll_c_aid_tracking_sc::general_work (int noutput_items __attri
current_synchro_data.Prompt_Q = static_cast<double>((d_correlator_outs_16sc[1]).imag());
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample (Hybridization OK!)
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + d_correlation_length_samples + d_rem_code_phase_samples) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
current_synchro_data.Carrier_phase_rads = GPS_TWO_PI * d_acc_carrier_phase_cycles;
current_synchro_data.Carrier_Doppler_hz = d_carrier_doppler_hz;// todo: project the carrier doppler
current_synchro_data.CN0_dB_hz = d_CN0_SNV_dB_Hz;
@ -577,7 +575,6 @@ int gps_l1_ca_dll_pll_c_aid_tracking_sc::general_work (int noutput_items __attri
current_synchro_data.System = {'G'};
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + d_correlation_length_samples + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
}
*out[0] = current_synchro_data;
if(d_dump)

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@ -82,9 +82,9 @@ void Gps_L1_Ca_Dll_Pll_Tracking_cc::forecast (int noutput_items,
gr_vector_int &ninput_items_required)
{
if (noutput_items != 0)
{
ninput_items_required[0] = static_cast<int>(d_vector_length) * 2; //set the required available samples in each call
}
{
ninput_items_required[0] = static_cast<int>(d_vector_length) * 2; //set the required available samples in each call
}
}
@ -98,8 +98,8 @@ Gps_L1_Ca_Dll_Pll_Tracking_cc::Gps_L1_Ca_Dll_Pll_Tracking_cc(
float pll_bw_hz,
float dll_bw_hz,
float early_late_space_chips) :
gr::block("Gps_L1_Ca_Dll_Pll_Tracking_cc", gr::io_signature::make(1, 1, sizeof(gr_complex)),
gr::io_signature::make(1, 1, sizeof(Gnss_Synchro)))
gr::block("Gps_L1_Ca_Dll_Pll_Tracking_cc", gr::io_signature::make(1, 1, sizeof(gr_complex)),
gr::io_signature::make(1, 1, sizeof(Gnss_Synchro)))
{
// Telemetry bit synchronization message port input
this->message_port_register_in(pmt::mp("preamble_timestamp_s"));
@ -129,9 +129,9 @@ Gps_L1_Ca_Dll_Pll_Tracking_cc::Gps_L1_Ca_Dll_Pll_Tracking_cc(
d_n_correlator_taps = 3; // Early, Prompt, and Late
d_correlator_outs = static_cast<gr_complex*>(volk_gnsssdr_malloc(d_n_correlator_taps*sizeof(gr_complex), volk_gnsssdr_get_alignment()));
for (int n = 0; n < d_n_correlator_taps; n++)
{
d_correlator_outs[n] = gr_complex(0,0);
}
{
d_correlator_outs[n] = gr_complex(0,0);
}
d_local_code_shift_chips = static_cast<float*>(volk_gnsssdr_malloc(d_n_correlator_taps*sizeof(float), volk_gnsssdr_get_alignment()));
// Set TAPs delay values [chips]
d_local_code_shift_chips[0] = - d_early_late_spc_chips;
@ -218,9 +218,9 @@ void Gps_L1_Ca_Dll_Pll_Tracking_cc::start_tracking()
double corrected_acq_phase_samples, delay_correction_samples;
corrected_acq_phase_samples = fmod((d_acq_code_phase_samples + T_prn_diff_seconds * N_prn_diff * static_cast<double>(d_fs_in)), T_prn_true_samples);
if (corrected_acq_phase_samples < 0)
{
corrected_acq_phase_samples = T_prn_mod_samples + corrected_acq_phase_samples;
}
{
corrected_acq_phase_samples = T_prn_mod_samples + corrected_acq_phase_samples;
}
delay_correction_samples = d_acq_code_phase_samples - corrected_acq_phase_samples;
d_acq_code_phase_samples = corrected_acq_phase_samples;
@ -237,9 +237,9 @@ void Gps_L1_Ca_Dll_Pll_Tracking_cc::start_tracking()
multicorrelator_cpu.set_local_code_and_taps(static_cast<int>(GPS_L1_CA_CODE_LENGTH_CHIPS), d_ca_code, d_local_code_shift_chips);
for (int n = 0; n < d_n_correlator_taps; n++)
{
d_correlator_outs[n] = gr_complex(0,0);
}
{
d_correlator_outs[n] = gr_complex(0,0);
}
d_carrier_lock_fail_counter = 0;
d_rem_code_phase_samples = 0;
@ -296,200 +296,196 @@ int Gps_L1_Ca_Dll_Pll_Tracking_cc::general_work (int noutput_items __attribute__
Gnss_Synchro current_synchro_data = Gnss_Synchro();
if (d_enable_tracking == true)
{
// Fill the acquisition data
current_synchro_data = *d_acquisition_gnss_synchro;
// Receiver signal alignment
if (d_pull_in == true)
{
// Fill the acquisition data
current_synchro_data = *d_acquisition_gnss_synchro;
// Receiver signal alignment
if (d_pull_in == true)
{
int samples_offset;
double acq_trk_shif_correction_samples;
int acq_to_trk_delay_samples;
acq_to_trk_delay_samples = d_sample_counter - d_acq_sample_stamp;
acq_trk_shif_correction_samples = d_current_prn_length_samples - fmod(static_cast<float>(acq_to_trk_delay_samples), static_cast<float>(d_current_prn_length_samples));
samples_offset = round(d_acq_code_phase_samples + acq_trk_shif_correction_samples);
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
d_sample_counter = d_sample_counter + samples_offset; // count for the processed samples
d_pull_in = false;
// take into account the carrier cycles accumulated in the pull in signal alignment
d_acc_carrier_phase_rad -= d_carrier_phase_step_rad * samples_offset;
current_synchro_data.Carrier_phase_rads = d_acc_carrier_phase_rad;
current_synchro_data.Carrier_Doppler_hz = d_carrier_doppler_hz;
*out[0] = current_synchro_data;
consume_each(samples_offset); // shift input to perform alignment with local replica
return 1;
}
// ################# CARRIER WIPEOFF AND CORRELATORS ##############################
// perform carrier wipe-off and compute Early, Prompt and Late correlation
multicorrelator_cpu.set_input_output_vectors(d_correlator_outs, in);
multicorrelator_cpu.Carrier_wipeoff_multicorrelator_resampler(d_rem_carr_phase_rad,
d_carrier_phase_step_rad,
d_rem_code_phase_chips,
d_code_phase_step_chips,
d_current_prn_length_samples);
// ################## PLL ##########################################################
// PLL discriminator
// Update PLL discriminator [rads/Ti -> Secs/Ti]
carr_error_hz = pll_cloop_two_quadrant_atan(d_correlator_outs[1]) / GPS_TWO_PI; // prompt output
// Carrier discriminator filter
carr_error_filt_hz = d_carrier_loop_filter.get_carrier_nco(carr_error_hz);
// New carrier Doppler frequency estimation
d_carrier_doppler_hz = d_acq_carrier_doppler_hz + carr_error_filt_hz;
// New code Doppler frequency estimation
d_code_freq_chips = GPS_L1_CA_CODE_RATE_HZ + ((d_carrier_doppler_hz * GPS_L1_CA_CODE_RATE_HZ) / GPS_L1_FREQ_HZ);
// ################## DLL ##########################################################
// DLL discriminator
code_error_chips = dll_nc_e_minus_l_normalized(d_correlator_outs[0], d_correlator_outs[2]); // [chips/Ti] //early and late
// Code discriminator filter
code_error_filt_chips = d_code_loop_filter.get_code_nco(code_error_chips); // [chips/second]
double code_error_filt_secs = (GPS_L1_CA_CODE_PERIOD * code_error_filt_chips) / GPS_L1_CA_CODE_RATE_HZ; // [seconds]
// ################## CARRIER AND CODE NCO BUFFER ALIGNEMENT #######################
// keep alignment parameters for the next input buffer
// Compute the next buffer length based in the new period of the PRN sequence and the code phase error estimation
double T_chip_seconds = 1.0 / static_cast<double>(d_code_freq_chips);
double T_prn_seconds = T_chip_seconds * GPS_L1_CA_CODE_LENGTH_CHIPS;
double T_prn_samples = T_prn_seconds * static_cast<double>(d_fs_in);
double K_blk_samples = T_prn_samples + d_rem_code_phase_samples + code_error_filt_secs * static_cast<double>(d_fs_in);
d_current_prn_length_samples = round(K_blk_samples); // round to a discrete number of samples
//################### PLL COMMANDS #################################################
// carrier phase step (NCO phase increment per sample) [rads/sample]
d_carrier_phase_step_rad = GPS_TWO_PI * d_carrier_doppler_hz / static_cast<double>(d_fs_in);
// remnant carrier phase to prevent overflow in the code NCO
d_rem_carr_phase_rad = d_rem_carr_phase_rad + d_carrier_phase_step_rad * d_current_prn_length_samples;
d_rem_carr_phase_rad = fmod(d_rem_carr_phase_rad, GPS_TWO_PI);
// carrier phase accumulator
d_acc_carrier_phase_rad -= d_carrier_phase_step_rad * d_current_prn_length_samples;
//################### DLL COMMANDS #################################################
// code phase step (Code resampler phase increment per sample) [chips/sample]
d_code_phase_step_chips = d_code_freq_chips / static_cast<double>(d_fs_in);
// remnant code phase [chips]
d_rem_code_phase_samples = K_blk_samples - d_current_prn_length_samples; // rounding error < 1 sample
d_rem_code_phase_chips = d_code_freq_chips * (d_rem_code_phase_samples / static_cast<double>(d_fs_in));
// ####### CN0 ESTIMATION AND LOCK DETECTORS ######
if (d_cn0_estimation_counter < CN0_ESTIMATION_SAMPLES)
{
// fill buffer with prompt correlator output values
d_Prompt_buffer[d_cn0_estimation_counter] = d_correlator_outs[1]; //prompt
d_cn0_estimation_counter++;
}
else
{
d_cn0_estimation_counter = 0;
// Code lock indicator
d_CN0_SNV_dB_Hz = cn0_svn_estimator(d_Prompt_buffer, CN0_ESTIMATION_SAMPLES, d_fs_in, GPS_L1_CA_CODE_LENGTH_CHIPS);
// Carrier lock indicator
d_carrier_lock_test = carrier_lock_detector(d_Prompt_buffer, CN0_ESTIMATION_SAMPLES);
// Loss of lock detection
if (d_carrier_lock_test < d_carrier_lock_threshold or d_CN0_SNV_dB_Hz < MINIMUM_VALID_CN0)
{
d_carrier_lock_fail_counter++;
}
else
{
if (d_carrier_lock_fail_counter > 0) d_carrier_lock_fail_counter--;
}
if (d_carrier_lock_fail_counter > MAXIMUM_LOCK_FAIL_COUNTER)
{
std::cout << "Loss of lock in channel " << d_channel << "!" << std::endl;
LOG(INFO) << "Loss of lock in channel " << d_channel << "!";
this->message_port_pub(pmt::mp("events"), pmt::from_long(3)); // 3 -> loss of lock
d_carrier_lock_fail_counter = 0;
d_enable_tracking = false; // TODO: check if disabling tracking is consistent with the channel state machine
}
}
// ########### Output the tracking data to navigation and PVT ##########
current_synchro_data.Prompt_I = static_cast<double>((d_correlator_outs[1]).real());
current_synchro_data.Prompt_Q = static_cast<double>((d_correlator_outs[1]).imag());
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter + d_current_prn_length_samples) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
int samples_offset;
double acq_trk_shif_correction_samples;
int acq_to_trk_delay_samples;
acq_to_trk_delay_samples = d_sample_counter - d_acq_sample_stamp;
acq_trk_shif_correction_samples = d_current_prn_length_samples - fmod(static_cast<float>(acq_to_trk_delay_samples), static_cast<float>(d_current_prn_length_samples));
samples_offset = round(d_acq_code_phase_samples + acq_trk_shif_correction_samples);
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
d_sample_counter = d_sample_counter + samples_offset; // count for the processed samples
d_pull_in = false;
// take into account the carrier cycles accumulated in the pull in signal alignment
d_acc_carrier_phase_rad -= d_carrier_phase_step_rad * samples_offset;
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 = 1;
*out[0] = current_synchro_data;
consume_each(samples_offset); // shift input to perform alignment with local replica
return 1;
}
else
{
for (int n = 0; n < d_n_correlator_taps; n++)
{
d_correlator_outs[n] = gr_complex(0,0);
}
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter + d_current_prn_length_samples) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
current_synchro_data.Rem_code_phase_secs = d_rem_code_phase_samples / static_cast<double>(d_fs_in);
current_synchro_data.System = {'G'};
// ################# CARRIER WIPEOFF AND CORRELATORS ##############################
// perform carrier wipe-off and compute Early, Prompt and Late correlation
multicorrelator_cpu.set_input_output_vectors(d_correlator_outs, in);
multicorrelator_cpu.Carrier_wipeoff_multicorrelator_resampler(d_rem_carr_phase_rad,
d_carrier_phase_step_rad,
d_rem_code_phase_chips,
d_code_phase_step_chips,
d_current_prn_length_samples);
// ################## PLL ##########################################################
// PLL discriminator
// Update PLL discriminator [rads/Ti -> Secs/Ti]
carr_error_hz = pll_cloop_two_quadrant_atan(d_correlator_outs[1]) / GPS_TWO_PI; // prompt output
// Carrier discriminator filter
carr_error_filt_hz = d_carrier_loop_filter.get_carrier_nco(carr_error_hz);
// New carrier Doppler frequency estimation
d_carrier_doppler_hz = d_acq_carrier_doppler_hz + carr_error_filt_hz;
// New code Doppler frequency estimation
d_code_freq_chips = GPS_L1_CA_CODE_RATE_HZ + ((d_carrier_doppler_hz * GPS_L1_CA_CODE_RATE_HZ) / GPS_L1_FREQ_HZ);
// ################## DLL ##########################################################
// DLL discriminator
code_error_chips = dll_nc_e_minus_l_normalized(d_correlator_outs[0], d_correlator_outs[2]); // [chips/Ti] //early and late
// Code discriminator filter
code_error_filt_chips = d_code_loop_filter.get_code_nco(code_error_chips); // [chips/second]
double code_error_filt_secs = (GPS_L1_CA_CODE_PERIOD * code_error_filt_chips) / GPS_L1_CA_CODE_RATE_HZ; // [seconds]
// ################## CARRIER AND CODE NCO BUFFER ALIGNEMENT #######################
// keep alignment parameters for the next input buffer
// Compute the next buffer length based in the new period of the PRN sequence and the code phase error estimation
double T_chip_seconds = 1.0 / static_cast<double>(d_code_freq_chips);
double T_prn_seconds = T_chip_seconds * GPS_L1_CA_CODE_LENGTH_CHIPS;
double T_prn_samples = T_prn_seconds * static_cast<double>(d_fs_in);
double K_blk_samples = T_prn_samples + d_rem_code_phase_samples + code_error_filt_secs * static_cast<double>(d_fs_in);
d_current_prn_length_samples = round(K_blk_samples); // round to a discrete number of samples
//################### PLL COMMANDS #################################################
// carrier phase step (NCO phase increment per sample) [rads/sample]
d_carrier_phase_step_rad = GPS_TWO_PI * d_carrier_doppler_hz / static_cast<double>(d_fs_in);
// remnant carrier phase to prevent overflow in the code NCO
d_rem_carr_phase_rad = d_rem_carr_phase_rad + d_carrier_phase_step_rad * d_current_prn_length_samples;
d_rem_carr_phase_rad = fmod(d_rem_carr_phase_rad, GPS_TWO_PI);
// carrier phase accumulator
d_acc_carrier_phase_rad -= d_carrier_phase_step_rad * d_current_prn_length_samples;
//################### DLL COMMANDS #################################################
// code phase step (Code resampler phase increment per sample) [chips/sample]
d_code_phase_step_chips = d_code_freq_chips / static_cast<double>(d_fs_in);
// remnant code phase [chips]
d_rem_code_phase_samples = K_blk_samples - d_current_prn_length_samples; // rounding error < 1 sample
d_rem_code_phase_chips = d_code_freq_chips * (d_rem_code_phase_samples / static_cast<double>(d_fs_in));
// ####### CN0 ESTIMATION AND LOCK DETECTORS ######
if (d_cn0_estimation_counter < CN0_ESTIMATION_SAMPLES)
{
// fill buffer with prompt correlator output values
d_Prompt_buffer[d_cn0_estimation_counter] = d_correlator_outs[1]; //prompt
d_cn0_estimation_counter++;
}
else
{
d_cn0_estimation_counter = 0;
// Code lock indicator
d_CN0_SNV_dB_Hz = cn0_svn_estimator(d_Prompt_buffer, CN0_ESTIMATION_SAMPLES, d_fs_in, GPS_L1_CA_CODE_LENGTH_CHIPS);
// Carrier lock indicator
d_carrier_lock_test = carrier_lock_detector(d_Prompt_buffer, CN0_ESTIMATION_SAMPLES);
// Loss of lock detection
if (d_carrier_lock_test < d_carrier_lock_threshold or d_CN0_SNV_dB_Hz < MINIMUM_VALID_CN0)
{
d_carrier_lock_fail_counter++;
}
else
{
if (d_carrier_lock_fail_counter > 0) d_carrier_lock_fail_counter--;
}
if (d_carrier_lock_fail_counter > MAXIMUM_LOCK_FAIL_COUNTER)
{
std::cout << "Loss of lock in channel " << d_channel << "!" << std::endl;
LOG(INFO) << "Loss of lock in channel " << d_channel << "!";
this->message_port_pub(pmt::mp("events"), pmt::from_long(3)); // 3 -> loss of lock
d_carrier_lock_fail_counter = 0;
d_enable_tracking = false; // TODO: check if disabling tracking is consistent with the channel state machine
}
}
// ########### Output the tracking data to navigation and PVT ##########
current_synchro_data.Prompt_I = static_cast<double>((d_correlator_outs[1]).real());
current_synchro_data.Prompt_Q = static_cast<double>((d_correlator_outs[1]).imag());
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter + d_current_prn_length_samples) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
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 = 1;
}
else
{
for (int n = 0; n < d_n_correlator_taps; n++)
{
d_correlator_outs[n] = gr_complex(0,0);
}
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter + d_current_prn_length_samples) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
current_synchro_data.System = {'G'};
}
//assign the GNURadio block output data
*out[0] = current_synchro_data;
if(d_dump)
{
// MULTIPLEXED FILE RECORDING - Record results to file
float prompt_I;
float prompt_Q;
float tmp_E, tmp_P, tmp_L;
double tmp_double;
unsigned long int tmp_long;
prompt_I = d_correlator_outs[1].real();
prompt_Q = d_correlator_outs[1].imag();
tmp_E = std::abs<float>(d_correlator_outs[0]);
tmp_P = std::abs<float>(d_correlator_outs[1]);
tmp_L = std::abs<float>(d_correlator_outs[2]);
try
{
// MULTIPLEXED FILE RECORDING - Record results to file
float prompt_I;
float prompt_Q;
float tmp_E, tmp_P, tmp_L;
double tmp_double;
unsigned long int tmp_long;
prompt_I = d_correlator_outs[1].real();
prompt_Q = d_correlator_outs[1].imag();
tmp_E = std::abs<float>(d_correlator_outs[0]);
tmp_P = std::abs<float>(d_correlator_outs[1]);
tmp_L = std::abs<float>(d_correlator_outs[2]);
try
{
// EPR
d_dump_file.write(reinterpret_cast<char*>(&tmp_E), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&tmp_P), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&tmp_L), sizeof(float));
// PROMPT I and Q (to analyze navigation symbols)
d_dump_file.write(reinterpret_cast<char*>(&prompt_I), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&prompt_Q), sizeof(float));
// PRN start sample stamp
tmp_long = d_sample_counter + d_current_prn_length_samples;
d_dump_file.write(reinterpret_cast<char*>(&tmp_long), sizeof(unsigned long int));
// accumulated carrier phase
d_dump_file.write(reinterpret_cast<char*>(&d_acc_carrier_phase_rad), sizeof(double));
// EPR
d_dump_file.write(reinterpret_cast<char*>(&tmp_E), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&tmp_P), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&tmp_L), sizeof(float));
// PROMPT I and Q (to analyze navigation symbols)
d_dump_file.write(reinterpret_cast<char*>(&prompt_I), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&prompt_Q), sizeof(float));
// PRN start sample stamp
tmp_long = d_sample_counter + d_current_prn_length_samples;
d_dump_file.write(reinterpret_cast<char*>(&tmp_long), sizeof(unsigned long int));
// accumulated carrier phase
d_dump_file.write(reinterpret_cast<char*>(&d_acc_carrier_phase_rad), sizeof(double));
// carrier and code frequency
d_dump_file.write(reinterpret_cast<char*>(&d_carrier_doppler_hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_code_freq_chips), sizeof(double));
// carrier and code frequency
d_dump_file.write(reinterpret_cast<char*>(&d_carrier_doppler_hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_code_freq_chips), sizeof(double));
// PLL commands
d_dump_file.write(reinterpret_cast<char*>(&carr_error_hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&carr_error_filt_hz), sizeof(double));
// PLL commands
d_dump_file.write(reinterpret_cast<char*>(&carr_error_hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&carr_error_filt_hz), sizeof(double));
// DLL commands
d_dump_file.write(reinterpret_cast<char*>(&code_error_chips), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&code_error_filt_chips), sizeof(double));
// DLL commands
d_dump_file.write(reinterpret_cast<char*>(&code_error_chips), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&code_error_filt_chips), sizeof(double));
// CN0 and carrier lock test
d_dump_file.write(reinterpret_cast<char*>(&d_CN0_SNV_dB_Hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_carrier_lock_test), sizeof(double));
// CN0 and carrier lock test
d_dump_file.write(reinterpret_cast<char*>(&d_CN0_SNV_dB_Hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_carrier_lock_test), sizeof(double));
// AUX vars (for debug purposes)
tmp_double = d_rem_code_phase_samples;
d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
tmp_double = static_cast<double>(d_sample_counter);
d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
}
catch (const std::ifstream::failure &e)
{
LOG(WARNING) << "Exception writing trk dump file " << e.what();
}
// AUX vars (for debug purposes)
tmp_double = d_rem_code_phase_samples;
d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
tmp_double = static_cast<double>(d_sample_counter);
d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
}
catch (const std::ifstream::failure &e)
{
LOG(WARNING) << "Exception writing trk dump file " << e.what();
}
}
consume_each(d_current_prn_length_samples); // this is necessary in gr::block derivates
d_sample_counter += d_current_prn_length_samples; // count for the processed samples
return 1; // output tracking result ALWAYS even in the case of d_enable_tracking==false
}
@ -501,23 +497,23 @@ void Gps_L1_Ca_Dll_Pll_Tracking_cc::set_channel(unsigned int channel)
LOG(INFO) << "Tracking Channel set to " << d_channel;
// ############# ENABLE DATA FILE LOG #################
if (d_dump == true)
{
if (d_dump_file.is_open() == false)
{
if (d_dump_file.is_open() == false)
{
try
{
d_dump_filename.append(boost::lexical_cast<std::string>(d_channel));
d_dump_filename.append(".dat");
d_dump_file.exceptions (std::ifstream::failbit | std::ifstream::badbit);
d_dump_file.open(d_dump_filename.c_str(), std::ios::out | std::ios::binary);
LOG(INFO) << "Tracking dump enabled on channel " << d_channel << " Log file: " << d_dump_filename.c_str();
}
catch (const std::ifstream::failure &e)
{
LOG(WARNING) << "channel " << d_channel << " Exception opening trk dump file " << e.what();
}
}
try
{
d_dump_filename.append(boost::lexical_cast<std::string>(d_channel));
d_dump_filename.append(".dat");
d_dump_file.exceptions (std::ifstream::failbit | std::ifstream::badbit);
d_dump_file.open(d_dump_filename.c_str(), std::ios::out | std::ios::binary);
LOG(INFO) << "Tracking dump enabled on channel " << d_channel << " Log file: " << d_dump_filename.c_str();
}
catch (const std::ifstream::failure &e)
{
LOG(WARNING) << "channel " << d_channel << " Exception opening trk dump file " << e.what();
}
}
}
}

View File

@ -81,9 +81,9 @@ void gps_l2_m_dll_pll_tracking_cc::forecast (int noutput_items,
gr_vector_int &ninput_items_required)
{
if (noutput_items != 0)
{
ninput_items_required[0] = static_cast<int>(d_vector_length) * 2; //set the required available samples in each call
}
{
ninput_items_required[0] = static_cast<int>(d_vector_length) * 2; //set the required available samples in each call
}
}
@ -97,8 +97,8 @@ gps_l2_m_dll_pll_tracking_cc::gps_l2_m_dll_pll_tracking_cc(
float pll_bw_hz,
float dll_bw_hz,
float early_late_space_chips) :
gr::block("gps_l2_m_dll_pll_tracking_cc", gr::io_signature::make(1, 1, sizeof(gr_complex)),
gr::io_signature::make(1, 1, sizeof(Gnss_Synchro)))
gr::block("gps_l2_m_dll_pll_tracking_cc", gr::io_signature::make(1, 1, sizeof(gr_complex)),
gr::io_signature::make(1, 1, sizeof(Gnss_Synchro)))
{
// Telemetry bit synchronization message port input
this->message_port_register_in(pmt::mp("preamble_timestamp_s"));
@ -110,6 +110,8 @@ gps_l2_m_dll_pll_tracking_cc::gps_l2_m_dll_pll_tracking_cc(
d_vector_length = vector_length;
d_dump_filename = dump_filename;
d_current_prn_length_samples = static_cast<int>(d_vector_length);
// DLL/PLL filter initialization
d_carrier_loop_filter=Tracking_2nd_PLL_filter(GPS_L2_M_PERIOD);
d_code_loop_filter=Tracking_2nd_DLL_filter(GPS_L2_M_PERIOD);
@ -129,17 +131,16 @@ gps_l2_m_dll_pll_tracking_cc::gps_l2_m_dll_pll_tracking_cc(
d_n_correlator_taps = 3; // Early, Prompt, and Late
d_correlator_outs = static_cast<gr_complex*>(volk_gnsssdr_malloc(d_n_correlator_taps*sizeof(gr_complex), volk_gnsssdr_get_alignment()));
for (int n = 0; n < d_n_correlator_taps; n++)
{
d_correlator_outs[n] = gr_complex(0,0);
}
{
d_correlator_outs[n] = gr_complex(0,0);
}
d_local_code_shift_chips = static_cast<float*>(volk_gnsssdr_malloc(d_n_correlator_taps*sizeof(float), volk_gnsssdr_get_alignment()));
// Set TAPs delay values [chips]
d_local_code_shift_chips[0] = - d_early_late_spc_chips;
d_local_code_shift_chips[1] = 0.0;
d_local_code_shift_chips[2] = d_early_late_spc_chips;
multicorrelator_cpu.init(2 * d_vector_length, d_n_correlator_taps);
multicorrelator_cpu.init(2 * d_current_prn_length_samples, d_n_correlator_taps);
//--- Perform initializations ------------------------------
// define initial code frequency basis of NCO
@ -157,8 +158,6 @@ gps_l2_m_dll_pll_tracking_cc::gps_l2_m_dll_pll_tracking_cc(
d_enable_tracking = false;
d_pull_in = false;
d_current_prn_length_samples = static_cast<int>(d_vector_length);
// CN0 estimation and lock detector buffers
d_cn0_estimation_counter = 0;
d_Prompt_buffer = new gr_complex[GPS_L2M_CN0_ESTIMATION_SAMPLES];
@ -169,7 +168,6 @@ gps_l2_m_dll_pll_tracking_cc::gps_l2_m_dll_pll_tracking_cc(
systemName["G"] = std::string("GPS");
set_relative_rate(1.0/((double)d_vector_length*2));
//set_min_output_buffer((long int)300);
d_acquisition_gnss_synchro = 0;
@ -184,7 +182,7 @@ gps_l2_m_dll_pll_tracking_cc::gps_l2_m_dll_pll_tracking_cc(
d_code_phase_step_chips = 0.0;
d_carrier_phase_step_rad = 0.0;
LOG(INFO) << "d_vector_length" << d_vector_length;
set_relative_rate(1.0 / static_cast<double>(d_vector_length));
}
@ -195,12 +193,12 @@ void gps_l2_m_dll_pll_tracking_cc::start_tracking()
*/
d_acq_code_phase_samples = d_acquisition_gnss_synchro->Acq_delay_samples;
d_acq_carrier_doppler_hz = d_acquisition_gnss_synchro->Acq_doppler_hz;
d_acq_sample_stamp = d_acquisition_gnss_synchro->Acq_samplestamp_samples;
d_acq_sample_stamp = d_acquisition_gnss_synchro->Acq_samplestamp_samples;
long int acq_trk_diff_samples;
float acq_trk_diff_seconds;
acq_trk_diff_samples = static_cast<long int>(d_sample_counter) - static_cast<long int>(d_acq_sample_stamp);//-d_vector_length;
LOG(INFO) << "Number of samples between Acquisition and Tracking =" << acq_trk_diff_samples;
double acq_trk_diff_seconds;
acq_trk_diff_samples = static_cast<long int>(d_sample_counter) - static_cast<long int>(d_acq_sample_stamp); //-d_vector_length;
DLOG(INFO) << "Number of samples between Acquisition and Tracking =" << acq_trk_diff_samples;
acq_trk_diff_seconds = static_cast<float>(acq_trk_diff_samples) / static_cast<float>(d_fs_in);
// Doppler effect
// Fd=(C/(C+Vr))*F
@ -213,23 +211,23 @@ void gps_l2_m_dll_pll_tracking_cc::start_tracking()
d_code_phase_step_chips = static_cast<double>(d_code_freq_chips) / static_cast<double>(d_fs_in);
T_chip_mod_seconds = 1/d_code_freq_chips;
T_prn_mod_seconds = T_chip_mod_seconds * GPS_L2_M_CODE_LENGTH_CHIPS;
T_prn_mod_samples = T_prn_mod_seconds * static_cast<float>(d_fs_in);
T_prn_mod_samples = T_prn_mod_seconds * static_cast<double>(d_fs_in);
d_current_prn_length_samples = round(T_prn_mod_samples);
double T_prn_true_seconds = GPS_L2_M_CODE_LENGTH_CHIPS / GPS_L2_M_CODE_RATE_HZ;
double T_prn_true_samples = T_prn_true_seconds * static_cast<float>(d_fs_in);
double T_prn_true_samples = T_prn_true_seconds * static_cast<double>(d_fs_in);
double T_prn_diff_seconds = T_prn_true_seconds - T_prn_mod_seconds;
double N_prn_diff = acq_trk_diff_seconds / T_prn_true_seconds;
double corrected_acq_phase_samples, delay_correction_samples;
corrected_acq_phase_samples = fmod((d_acq_code_phase_samples + T_prn_diff_seconds * N_prn_diff * static_cast<float>(d_fs_in)), T_prn_true_samples);
corrected_acq_phase_samples = fmod((d_acq_code_phase_samples + T_prn_diff_seconds * N_prn_diff * static_cast<double>(d_fs_in)), T_prn_true_samples);
if (corrected_acq_phase_samples < 0)
{
corrected_acq_phase_samples = T_prn_mod_samples + corrected_acq_phase_samples;
}
{
corrected_acq_phase_samples = T_prn_mod_samples + corrected_acq_phase_samples;
}
delay_correction_samples = d_acq_code_phase_samples - corrected_acq_phase_samples;
//TODO: debug the algorithm implementation and enable correction
//d_acq_code_phase_samples = corrected_acq_phase_samples;
d_acq_code_phase_samples = corrected_acq_phase_samples;
d_carrier_doppler_hz = d_acq_carrier_doppler_hz;
d_carrier_phase_step_rad = GPS_L2_TWO_PI * d_carrier_doppler_hz / static_cast<double>(d_fs_in);
@ -243,15 +241,15 @@ void gps_l2_m_dll_pll_tracking_cc::start_tracking()
multicorrelator_cpu.set_local_code_and_taps(static_cast<int>(GPS_L2_M_CODE_LENGTH_CHIPS), d_ca_code, d_local_code_shift_chips);
for (int n = 0; n < d_n_correlator_taps; n++)
{
d_correlator_outs[n] = gr_complex(0,0);
}
{
d_correlator_outs[n] = gr_complex(0,0);
}
d_carrier_lock_fail_counter = 0;
d_rem_code_phase_samples = 0;
d_rem_carr_phase_rad = 0;
d_rem_carr_phase_rad = 0.0;
d_rem_code_phase_chips = 0.0;
d_acc_carrier_phase_rad = 0;
d_acc_carrier_phase_rad = 0.0;
d_code_phase_samples = d_acq_code_phase_samples;
@ -259,10 +257,9 @@ void gps_l2_m_dll_pll_tracking_cc::start_tracking()
sys = sys_.substr(0,1);
// DEBUG OUTPUT
std::cout << "Tracking start on channel " << d_channel << " for satellite " << Gnss_Satellite(systemName[sys], d_acquisition_gnss_synchro->PRN) <<" whith Doppler="<<d_acq_carrier_doppler_hz<<" [Hz]"<< std::endl;
std::cout << "Tracking start on channel " << d_channel << " for satellite " << Gnss_Satellite(systemName[sys], d_acquisition_gnss_synchro->PRN) << std::endl;
LOG(INFO) << "Starting tracking of satellite " << Gnss_Satellite(systemName[sys], d_acquisition_gnss_synchro->PRN) << " on channel " << d_channel;
// enable tracking
d_pull_in = true;
d_enable_tracking = true;
@ -303,190 +300,191 @@ int gps_l2_m_dll_pll_tracking_cc::general_work (int noutput_items __attribute__(
Gnss_Synchro **out = (Gnss_Synchro **) &output_items[0];
if (d_enable_tracking == true)
{
// Fill the acquisition data
current_synchro_data = *d_acquisition_gnss_synchro;
// Receiver signal alignment
if (d_pull_in == true)
{
// Fill the acquisition data
current_synchro_data = *d_acquisition_gnss_synchro;
// Receiver signal alignment
if (d_pull_in == true)
{
int samples_offset;
double acq_trk_shif_correction_samples;
int acq_to_trk_delay_samples;
acq_to_trk_delay_samples = (d_sample_counter - (d_acq_sample_stamp-d_current_prn_length_samples));
acq_trk_shif_correction_samples = -fmod(static_cast<float>(acq_to_trk_delay_samples), static_cast<float>(d_current_prn_length_samples));
samples_offset = round(d_acq_code_phase_samples + acq_trk_shif_correction_samples);//+(1.5*(d_fs_in/GPS_L2_M_CODE_RATE_HZ)));
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
d_sample_counter = d_sample_counter + samples_offset; //count for the processed samples
d_acc_carrier_phase_rad -= d_carrier_phase_step_rad * samples_offset;
current_synchro_data.Carrier_phase_rads = d_acc_carrier_phase_rad;
current_synchro_data.Carrier_Doppler_hz = d_carrier_doppler_hz;
*out[0] = current_synchro_data;
d_pull_in = false;
consume_each(samples_offset); //shift input to perform alignment with local replica
return 1;
}
// ################# CARRIER WIPEOFF AND CORRELATORS ##############################
// perform carrier wipe-off and compute Early, Prompt and Late correlation
multicorrelator_cpu.set_input_output_vectors(d_correlator_outs, in);
multicorrelator_cpu.Carrier_wipeoff_multicorrelator_resampler(d_rem_carr_phase_rad,
d_carrier_phase_step_rad,
d_rem_code_phase_chips,
d_code_phase_step_chips,
d_current_prn_length_samples);
// ################## PLL ##########################################################
// PLL discriminator
carr_error_hz = pll_cloop_two_quadrant_atan(d_correlator_outs[1]) / GPS_L2_TWO_PI;
// Carrier discriminator filter
carr_error_filt_hz = d_carrier_loop_filter.get_carrier_nco(carr_error_hz);
// New carrier Doppler frequency estimation
d_carrier_doppler_hz = d_acq_carrier_doppler_hz + carr_error_filt_hz;
// New code Doppler frequency estimation
d_code_freq_chips = GPS_L2_M_CODE_RATE_HZ + ((d_carrier_doppler_hz * GPS_L2_M_CODE_RATE_HZ) / GPS_L2_FREQ_HZ);
// ################## DLL ##########################################################
// DLL discriminator
code_error_chips = dll_nc_e_minus_l_normalized(d_correlator_outs[0], d_correlator_outs[2]); // [chips/Ti]
// Code discriminator filter
code_error_filt_chips = d_code_loop_filter.get_code_nco(code_error_chips); //[chips/second]
//Code phase accumulator
double code_error_filt_secs = (GPS_L2_M_PERIOD * code_error_filt_chips) / GPS_L2_M_CODE_RATE_HZ; //[seconds]
// ################## CARRIER AND CODE NCO BUFFER ALIGNEMENT #######################
// keep alignment parameters for the next input buffer
// Compute the next buffer length based in the new period of the PRN sequence and the code phase error estimation
double T_chip_seconds = 1.0 / d_code_freq_chips;
double T_prn_seconds = T_chip_seconds * GPS_L2_M_CODE_LENGTH_CHIPS;
double T_prn_samples = T_prn_seconds * static_cast<double>(d_fs_in);
double K_blk_samples = T_prn_samples + d_rem_code_phase_samples + code_error_filt_secs * static_cast<double>(d_fs_in);
d_current_prn_length_samples = round(K_blk_samples); // round to a discrete number of samples
//################### PLL COMMANDS #################################################
// carrier phase step (NCO phase increment per sample) [rads/sample]
d_carrier_phase_step_rad = GPS_L2_TWO_PI * d_carrier_doppler_hz / static_cast<double>(d_fs_in);
// remnant carrier phase to prevent overflow in the code NCO
d_rem_carr_phase_rad = d_rem_carr_phase_rad + d_carrier_phase_step_rad * d_current_prn_length_samples;
d_rem_carr_phase_rad = fmod(d_rem_carr_phase_rad, GPS_L2_TWO_PI);
// carrier phase accumulator
d_acc_carrier_phase_rad -= d_carrier_phase_step_rad * d_current_prn_length_samples;
//################### DLL COMMANDS #################################################
// code phase step (Code resampler phase increment per sample) [chips/sample]
d_code_phase_step_chips = d_code_freq_chips / static_cast<double>(d_fs_in);
// remnant code phase [chips]
d_rem_code_phase_samples = K_blk_samples - d_current_prn_length_samples; // rounding error < 1 sample
d_rem_code_phase_chips = d_code_freq_chips * (d_rem_code_phase_samples / static_cast<double>(d_fs_in));
// ####### CN0 ESTIMATION AND LOCK DETECTORS ######
if (d_cn0_estimation_counter < GPS_L2M_CN0_ESTIMATION_SAMPLES)
{
// fill buffer with prompt correlator output values
d_Prompt_buffer[d_cn0_estimation_counter] = d_correlator_outs[1];
d_cn0_estimation_counter++;
}
else
{
d_cn0_estimation_counter = 0;
// Code lock indicator
d_CN0_SNV_dB_Hz = cn0_svn_estimator(d_Prompt_buffer, GPS_L2M_CN0_ESTIMATION_SAMPLES, d_fs_in, GPS_L2_M_CODE_LENGTH_CHIPS);
// Carrier lock indicator
d_carrier_lock_test = carrier_lock_detector(d_Prompt_buffer, GPS_L2M_CN0_ESTIMATION_SAMPLES);
// Loss of lock detection
if (d_carrier_lock_test < d_carrier_lock_threshold or d_CN0_SNV_dB_Hz < GPS_L2M_MINIMUM_VALID_CN0)
{
d_carrier_lock_fail_counter++;
}
else
{
if (d_carrier_lock_fail_counter > 0) d_carrier_lock_fail_counter--;
}
if (d_carrier_lock_fail_counter > GPS_L2M_MAXIMUM_LOCK_FAIL_COUNTER)
{
std::cout << "Loss of lock in channel " << d_channel << "!" << std::endl;
LOG(INFO) << "Loss of lock in channel " << d_channel << "!";
this->message_port_pub(pmt::mp("events"), pmt::from_long(3));//3 -> loss of lock
d_carrier_lock_fail_counter = 0;
d_enable_tracking = false; // TODO: check if disabling tracking is consistent with the channel state machine
}
}
// ########### Output the tracking data to navigation and PVT ##########
current_synchro_data.Prompt_I = static_cast<double>(d_correlator_outs[1].real());
current_synchro_data.Prompt_Q = static_cast<double>(d_correlator_outs[1].imag());
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter + d_current_prn_length_samples) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
int samples_offset;
double acq_trk_shif_correction_samples;
int acq_to_trk_delay_samples;
acq_to_trk_delay_samples = d_sample_counter - d_acq_sample_stamp;
acq_trk_shif_correction_samples = d_current_prn_length_samples - fmod(static_cast<float>(acq_to_trk_delay_samples), static_cast<float>(d_current_prn_length_samples));
samples_offset = round(d_acq_code_phase_samples + acq_trk_shif_correction_samples);
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
d_sample_counter = d_sample_counter + samples_offset; // count for the processed samples
d_pull_in = false;
// take into account the carrier cycles accumulated in the pull in signal alignment
d_acc_carrier_phase_rad -= d_carrier_phase_step_rad * samples_offset;
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 = 20;
*out[0] = current_synchro_data;
consume_each(samples_offset); // shift input to perform alignment with local replica
return 1;
}
}
else
// ################# CARRIER WIPEOFF AND CORRELATORS ##############################
// perform carrier wipe-off and compute Early, Prompt and Late correlation
multicorrelator_cpu.set_input_output_vectors(d_correlator_outs, in);
multicorrelator_cpu.Carrier_wipeoff_multicorrelator_resampler(d_rem_carr_phase_rad,
d_carrier_phase_step_rad,
d_rem_code_phase_chips,
d_code_phase_step_chips,
d_current_prn_length_samples);
// ################## PLL ##########################################################
// PLL discriminator
// Update PLL discriminator [rads/Ti -> Secs/Ti]
carr_error_hz = pll_cloop_two_quadrant_atan(d_correlator_outs[1]) / GPS_L2_TWO_PI;
// Carrier discriminator filter
carr_error_filt_hz = d_carrier_loop_filter.get_carrier_nco(carr_error_hz);
// New carrier Doppler frequency estimation
d_carrier_doppler_hz = d_acq_carrier_doppler_hz + carr_error_filt_hz;
// New code Doppler frequency estimation
d_code_freq_chips = GPS_L2_M_CODE_RATE_HZ + ((d_carrier_doppler_hz * GPS_L2_M_CODE_RATE_HZ) / GPS_L2_FREQ_HZ);
// ################## DLL ##########################################################
// DLL discriminator
code_error_chips = dll_nc_e_minus_l_normalized(d_correlator_outs[0], d_correlator_outs[2]); // [chips/Ti]
// Code discriminator filter
code_error_filt_chips = d_code_loop_filter.get_code_nco(code_error_chips); //[chips/second]
double code_error_filt_secs = (GPS_L2_M_PERIOD * code_error_filt_chips) / GPS_L2_M_CODE_RATE_HZ; //[seconds]
// ################## CARRIER AND CODE NCO BUFFER ALIGNEMENT #######################
// keep alignment parameters for the next input buffer
// Compute the next buffer length based in the new period of the PRN sequence and the code phase error estimation
double T_chip_seconds = 1.0 / static_cast<double>(d_code_freq_chips);
double T_prn_seconds = T_chip_seconds * GPS_L2_M_CODE_LENGTH_CHIPS;
double T_prn_samples = T_prn_seconds * static_cast<double>(d_fs_in);
double K_blk_samples = T_prn_samples + d_rem_code_phase_samples + code_error_filt_secs * static_cast<double>(d_fs_in);
d_current_prn_length_samples = round(K_blk_samples); // round to a discrete number of samples
//################### PLL COMMANDS #################################################
// carrier phase step (NCO phase increment per sample) [rads/sample]
d_carrier_phase_step_rad = GPS_L2_TWO_PI * d_carrier_doppler_hz / static_cast<double>(d_fs_in);
// remnant carrier phase to prevent overflow in the code NCO
d_rem_carr_phase_rad = d_rem_carr_phase_rad + d_carrier_phase_step_rad * d_current_prn_length_samples;
d_rem_carr_phase_rad = fmod(d_rem_carr_phase_rad, GPS_L2_TWO_PI);
// carrier phase accumulator
d_acc_carrier_phase_rad -= d_carrier_phase_step_rad * d_current_prn_length_samples;
//################### DLL COMMANDS #################################################
// code phase step (Code resampler phase increment per sample) [chips/sample]
d_code_phase_step_chips = d_code_freq_chips / static_cast<double>(d_fs_in);
// remnant code phase [chips]
d_rem_code_phase_samples = K_blk_samples - d_current_prn_length_samples; // rounding error < 1 sample
d_rem_code_phase_chips = d_code_freq_chips * (d_rem_code_phase_samples / static_cast<double>(d_fs_in));
// ####### CN0 ESTIMATION AND LOCK DETECTORS ######
if (d_cn0_estimation_counter < GPS_L2M_CN0_ESTIMATION_SAMPLES)
{
for (int n = 0; n < d_n_correlator_taps; n++)
{
d_correlator_outs[n] = gr_complex(0,0);
}
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter + d_current_prn_length_samples) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
// fill buffer with prompt correlator output values
d_Prompt_buffer[d_cn0_estimation_counter] = d_correlator_outs[1];
d_cn0_estimation_counter++;
}
else
{
d_cn0_estimation_counter = 0;
// Code lock indicator
d_CN0_SNV_dB_Hz = cn0_svn_estimator(d_Prompt_buffer, GPS_L2M_CN0_ESTIMATION_SAMPLES, d_fs_in, GPS_L2_M_CODE_LENGTH_CHIPS);
// Carrier lock indicator
d_carrier_lock_test = carrier_lock_detector(d_Prompt_buffer, GPS_L2M_CN0_ESTIMATION_SAMPLES);
// Loss of lock detection
if (d_carrier_lock_test < d_carrier_lock_threshold or d_CN0_SNV_dB_Hz < GPS_L2M_MINIMUM_VALID_CN0)
{
d_carrier_lock_fail_counter++;
}
else
{
if (d_carrier_lock_fail_counter > 0) d_carrier_lock_fail_counter--;
}
if (d_carrier_lock_fail_counter > GPS_L2M_MAXIMUM_LOCK_FAIL_COUNTER)
{
std::cout << "Loss of lock in channel " << d_channel << "!" << std::endl;
LOG(INFO) << "Loss of lock in channel " << d_channel << "!";
this->message_port_pub(pmt::mp("events"), pmt::from_long(3));//3 -> loss of lock
d_carrier_lock_fail_counter = 0;
d_enable_tracking = false; // TODO: check if disabling tracking is consistent with the channel state machine
}
}
// ########### Output the tracking data to navigation and PVT ##########
current_synchro_data.Prompt_I = static_cast<double>(d_correlator_outs[1].real());
current_synchro_data.Prompt_Q = static_cast<double>(d_correlator_outs[1].imag());
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter + d_current_prn_length_samples) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
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 = 20;
}
else
{
for (int n = 0; n < d_n_correlator_taps; n++)
{
d_correlator_outs[n] = gr_complex(0,0);
}
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter + d_current_prn_length_samples) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
}
//assign the GNURadio block output data
*out[0] = current_synchro_data;
if(d_dump)
{
// MULTIPLEXED FILE RECORDING - Record results to file
float prompt_I;
float prompt_Q;
float tmp_E, tmp_P, tmp_L;
double tmp_double;
prompt_I = d_correlator_outs[1].real();
prompt_Q = d_correlator_outs[1].imag();
tmp_E = std::abs<float>(d_correlator_outs[0]);
tmp_P = std::abs<float>(d_correlator_outs[1]);
tmp_L = std::abs<float>(d_correlator_outs[2]);
try
{
// MULTIPLEXED FILE RECORDING - Record results to file
float prompt_I;
float prompt_Q;
float tmp_E, tmp_P, tmp_L;
double tmp_double;
prompt_I = d_correlator_outs[1].real();
prompt_Q = d_correlator_outs[1].imag();
tmp_E = std::abs<float>(d_correlator_outs[0]);
tmp_P = std::abs<float>(d_correlator_outs[1]);
tmp_L = std::abs<float>(d_correlator_outs[2]);
try
{
// EPR
d_dump_file.write(reinterpret_cast<char*>(&tmp_E), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&tmp_P), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&tmp_L), sizeof(float));
// PROMPT I and Q (to analyze navigation symbols)
d_dump_file.write(reinterpret_cast<char*>(&prompt_I), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&prompt_Q), sizeof(float));
// PRN start sample stamp
//tmp_float=(float)d_sample_counter;
d_dump_file.write(reinterpret_cast<char*>(&d_sample_counter), sizeof(unsigned long int));
// accumulated carrier phase
d_dump_file.write(reinterpret_cast<char*>(&d_acc_carrier_phase_rad), sizeof(double));
// EPR
d_dump_file.write(reinterpret_cast<char*>(&tmp_E), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&tmp_P), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&tmp_L), sizeof(float));
// PROMPT I and Q (to analyze navigation symbols)
d_dump_file.write(reinterpret_cast<char*>(&prompt_I), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&prompt_Q), sizeof(float));
// PRN start sample stamp
//tmp_float=(float)d_sample_counter;
d_dump_file.write(reinterpret_cast<char*>(&d_sample_counter), sizeof(unsigned long int));
// accumulated carrier phase
d_dump_file.write(reinterpret_cast<char*>(&d_acc_carrier_phase_rad), sizeof(double));
// carrier and code frequency
d_dump_file.write(reinterpret_cast<char*>(&d_carrier_doppler_hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_code_freq_chips), sizeof(double));
// carrier and code frequency
d_dump_file.write(reinterpret_cast<char*>(&d_carrier_doppler_hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_code_freq_chips), sizeof(double));
//PLL commands
d_dump_file.write(reinterpret_cast<char*>(&carr_error_hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_carrier_doppler_hz), sizeof(double));
//PLL commands
d_dump_file.write(reinterpret_cast<char*>(&carr_error_hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_carrier_doppler_hz), sizeof(double));
//DLL commands
d_dump_file.write(reinterpret_cast<char*>(&code_error_chips), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&code_error_filt_chips), sizeof(double));
//DLL commands
d_dump_file.write(reinterpret_cast<char*>(&code_error_chips), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&code_error_filt_chips), sizeof(double));
// CN0 and carrier lock test
d_dump_file.write(reinterpret_cast<char*>(&d_CN0_SNV_dB_Hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_carrier_lock_test), sizeof(double));
// CN0 and carrier lock test
d_dump_file.write(reinterpret_cast<char*>(&d_CN0_SNV_dB_Hz), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_carrier_lock_test), sizeof(double));
// AUX vars (for debug purposes)
tmp_double = d_rem_code_phase_samples;
d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
tmp_double = static_cast<double>(d_sample_counter + d_current_prn_length_samples);
d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
}
catch (std::ifstream::failure& e)
{
LOG(WARNING) << "Exception writing trk dump file " << e.what();
}
// AUX vars (for debug purposes)
tmp_double = d_rem_code_phase_samples;
d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
tmp_double = static_cast<double>(d_sample_counter + d_current_prn_length_samples);
d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
}
catch (std::ifstream::failure& e)
{
LOG(WARNING) << "Exception writing trk dump file " << e.what();
}
}
consume_each(d_current_prn_length_samples); // this is necessary in gr::block derivates
d_sample_counter += d_current_prn_length_samples; // count for the processed samples
return 1; // output tracking result ALWAYS even in the case of d_enable_tracking==false
@ -500,23 +498,23 @@ void gps_l2_m_dll_pll_tracking_cc::set_channel(unsigned int channel)
LOG(INFO) << "Tracking Channel set to " << d_channel;
// ############# ENABLE DATA FILE LOG #################
if (d_dump == true)
{
if (d_dump_file.is_open() == false)
{
if (d_dump_file.is_open() == false)
{
try
{
d_dump_filename.append(boost::lexical_cast<std::string>(d_channel));
d_dump_filename.append(".dat");
d_dump_file.exceptions (std::ifstream::failbit | std::ifstream::badbit);
d_dump_file.open(d_dump_filename.c_str(), std::ios::out | std::ios::binary);
LOG(INFO) << "Tracking dump enabled on channel " << d_channel << " Log file: " << d_dump_filename.c_str();
}
catch (std::ifstream::failure& e)
{
LOG(WARNING) << "channel " << d_channel << " Exception opening trk dump file " << e.what();
}
}
try
{
d_dump_filename.append(boost::lexical_cast<std::string>(d_channel));
d_dump_filename.append(".dat");
d_dump_file.exceptions (std::ifstream::failbit | std::ifstream::badbit);
d_dump_file.open(d_dump_filename.c_str(), std::ios::out | std::ios::binary);
LOG(INFO) << "Tracking dump enabled on channel " << d_channel << " Log file: " << d_dump_filename.c_str();
}
catch (std::ifstream::failure& e)
{
LOG(WARNING) << "channel " << d_channel << " Exception opening trk dump file " << e.what();
}
}
}
}

View File

@ -58,7 +58,6 @@ public:
double Carrier_Doppler_hz; //!< Set by Tracking processing block
double Carrier_phase_rads; //!< Set by Tracking processing block
double Tracking_timestamp_secs; //!< Set by Tracking processing block
double Rem_code_phase_secs; //!< Set by Tracking processing block
bool Flag_valid_symbol_output; //!< Set by Tracking processing block
int correlation_length_ms; //!< Set by Tracking processing block