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/*!
* \file galileo_e5a_dll_fll_pll_tracking_cc.h
* \brief Implementation of a code DLL + carrier PLL
* tracking block for Galileo E5a signals
* \author Marc Sales, 2014. marcsales92(at)gmail.com
* \based on work from:
* <ul>
* <li> Javier Arribas, 2011. jarribas(at)cttc.es
* <li> Luis Esteve, 2012. luis(at)epsilon-formacion.com
* </ul>
*
* -------------------------------------------------------------------------
*
* Copyright (C) 2010-2015 (see AUTHORS file for a list of contributors)
*
* GNSS-SDR is a software defined Global Navigation
* Satellite Systems receiver
*
* This file is part of GNSS-SDR.
*
* GNSS-SDR is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GNSS-SDR is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNSS-SDR. If not, see <http://www.gnu.org/licenses/>.
*
* -------------------------------------------------------------------------
*/
#include "galileo_e5a_dll_pll_tracking_cc.h"
#include <cmath>
#include <iostream>
#include <sstream>
#include <boost/lexical_cast.hpp>
#include <gnuradio/io_signature.h>
#include <gnuradio/fxpt.h> // fixed point sine and cosine
#include <glog/logging.h>
#include "gnss_synchro.h"
#include "galileo_e5_signal_processing.h"
#include "tracking_discriminators.h"
#include "lock_detectors.h"
#include "Galileo_E5a.h"
#include "Galileo_E1.h"
#include "control_message_factory.h"
/*!
* \todo Include in definition header file
*/
#define CN0_ESTIMATION_SAMPLES 20
#define MINIMUM_VALID_CN0 25
#define MAXIMUM_LOCK_FAIL_COUNTER 50
#define CARRIER_LOCK_THRESHOLD 0.85
using google::LogMessage;
galileo_e5a_dll_pll_tracking_cc_sptr
galileo_e5a_dll_pll_make_tracking_cc(
long if_freq,
long fs_in,
unsigned int vector_length,
boost::shared_ptr<gr::msg_queue> queue,
bool dump,
std::string dump_filename,
float pll_bw_hz,
float dll_bw_hz,
float pll_bw_init_hz,
float dll_bw_init_hz,
int ti_ms,
float early_late_space_chips)
{
return galileo_e5a_dll_pll_tracking_cc_sptr(new Galileo_E5a_Dll_Pll_Tracking_cc(if_freq,
fs_in, vector_length, queue, dump, dump_filename, pll_bw_hz, dll_bw_hz, pll_bw_init_hz, dll_bw_init_hz, ti_ms, early_late_space_chips));
}
void Galileo_E5a_Dll_Pll_Tracking_cc::forecast (int noutput_items,
gr_vector_int &ninput_items_required)
{
ninput_items_required[0] = static_cast<int>(d_vector_length)*2; //set the required available samples in each call
}
Galileo_E5a_Dll_Pll_Tracking_cc::Galileo_E5a_Dll_Pll_Tracking_cc(
long if_freq,
long fs_in,
unsigned int vector_length,
boost::shared_ptr<gr::msg_queue> queue,
bool dump,
std::string dump_filename,
float pll_bw_hz,
float dll_bw_hz,
float pll_bw_init_hz,
float dll_bw_init_hz,
int ti_ms,
float early_late_space_chips) :
gr::block("Galileo_E5a_Dll_Pll_Tracking_cc", gr::io_signature::make(1, 1, sizeof(gr_complex)),
gr::io_signature::make(1, 1, sizeof(Gnss_Synchro)))
{
this->set_relative_rate(1.0/vector_length);
// initialize internal vars
d_queue = queue;
d_dump = dump;
d_if_freq = if_freq;
d_fs_in = fs_in;
d_vector_length = vector_length;
d_dump_filename = dump_filename;
d_code_loop_filter = Tracking_2nd_DLL_filter(GALILEO_E5a_CODE_PERIOD);
d_carrier_loop_filter = Tracking_2nd_PLL_filter(GALILEO_E5a_CODE_PERIOD);
d_current_ti_ms = 1; // initializes with 1ms of integration time until secondary code lock
d_ti_ms = ti_ms;
d_dll_bw_hz = dll_bw_hz;
d_pll_bw_hz = pll_bw_hz;
d_dll_bw_init_hz = dll_bw_init_hz;
d_pll_bw_init_hz = pll_bw_init_hz;
// Initialize tracking ==========================================
d_code_loop_filter.set_DLL_BW(d_dll_bw_init_hz);
d_carrier_loop_filter.set_PLL_BW(d_pll_bw_init_hz);
//--- DLL variables --------------------------------------------------------
d_early_late_spc_chips = early_late_space_chips; // Define early-late offset (in chips)
// Initialization of local code replica
// Get space for a vector with the E5a primary code replicas sampled 1x/chip
d_codeQ = new gr_complex[static_cast<int>(Galileo_E5a_CODE_LENGTH_CHIPS) + 2];
d_codeI = new gr_complex[static_cast<int>(Galileo_E5a_CODE_LENGTH_CHIPS) + 2];
d_early_code = static_cast<gr_complex*>(volk_malloc(2 * d_vector_length * sizeof(gr_complex), volk_get_alignment()));
d_late_code = static_cast<gr_complex*>(volk_malloc(2 * d_vector_length * sizeof(gr_complex), volk_get_alignment()));
d_prompt_code = static_cast<gr_complex*>(volk_malloc(2 * d_vector_length * sizeof(gr_complex), volk_get_alignment()));
d_prompt_data_code = static_cast<gr_complex*>(volk_malloc(2 * d_vector_length * sizeof(gr_complex), volk_get_alignment()));
d_carr_sign = static_cast<gr_complex*>(volk_malloc(2 * d_vector_length * sizeof(gr_complex), volk_get_alignment()));
// correlator outputs (complex number)
d_Early = gr_complex(0, 0);
d_Prompt = gr_complex(0, 0);
d_Late = gr_complex(0, 0);
d_Prompt_data = gr_complex(0, 0);
//--- Perform initializations ------------------------------
// define initial code frequency basis of NCO
d_code_freq_chips = Galileo_E5a_CODE_CHIP_RATE_HZ;
// define residual code phase (in chips)
d_rem_code_phase_samples = 0.0;
// define residual carrier phase
d_rem_carr_phase_rad = 0.0;
//Filter error vars
d_code_error_filt_secs = 0.0;
// sample synchronization
d_sample_counter = 0;
d_acq_sample_stamp = 0;
d_last_seg = 0;
d_first_transition = false;
d_secondary_lock = false;
d_secondary_delay = 0;
d_integration_counter = 0;
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[CN0_ESTIMATION_SAMPLES];
d_carrier_lock_test = 1;
d_CN0_SNV_dB_Hz = 0;
d_carrier_lock_fail_counter = 0;
d_carrier_lock_threshold = CARRIER_LOCK_THRESHOLD;
d_channel_internal_queue = 0;
d_acquisition_gnss_synchro = 0;
d_channel = 0;
tmp_E = 0;
tmp_P = 0;
tmp_L = 0;
d_acq_code_phase_samples = 0;
d_acq_carrier_doppler_hz = 0;
d_carrier_doppler_hz = 0;
d_acc_carrier_phase_rad = 0;
d_code_phase_samples = 0;
d_acc_code_phase_secs = 0;
d_state = 0;
systemName["E"] = std::string("Galileo");
}
Galileo_E5a_Dll_Pll_Tracking_cc::~Galileo_E5a_Dll_Pll_Tracking_cc ()
{
d_dump_file.close();
volk_free(d_prompt_code);
volk_free(d_late_code);
volk_free(d_early_code);
volk_free(d_carr_sign);
volk_free(d_prompt_data_code);
delete[] d_codeI;
delete[] d_codeQ;
delete[] d_Prompt_buffer;
}
void Galileo_E5a_Dll_Pll_Tracking_cc::start_tracking()
{
/*
* correct the code phase according to the delay between acq and trk
*/
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;
long int 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;
LOG(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
double radial_velocity;
radial_velocity = (Galileo_E5a_FREQ_HZ + d_acq_carrier_doppler_hz)/Galileo_E5a_FREQ_HZ;
// new chip and prn sequence periods based on acq Doppler
double T_chip_mod_seconds;
double T_prn_mod_seconds;
double T_prn_mod_samples;
d_code_freq_chips = radial_velocity * Galileo_E5a_CODE_CHIP_RATE_HZ;
T_chip_mod_seconds = 1/d_code_freq_chips;
T_prn_mod_seconds = T_chip_mod_seconds * Galileo_E5a_CODE_LENGTH_CHIPS;
T_prn_mod_samples = T_prn_mod_seconds * static_cast<float>(d_fs_in);
d_current_prn_length_samples = round(T_prn_mod_samples);
double T_prn_true_seconds = Galileo_E5a_CODE_LENGTH_CHIPS / Galileo_E5a_CODE_CHIP_RATE_HZ;
double T_prn_true_samples = T_prn_true_seconds * static_cast<float>(d_fs_in);
double T_prn_diff_seconds;
T_prn_diff_seconds = T_prn_true_seconds - T_prn_mod_seconds;
double N_prn_diff;
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);
if (corrected_acq_phase_samples < 0)
{
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;
d_carrier_doppler_hz = d_acq_carrier_doppler_hz;
// DLL/PLL filter initialization
d_carrier_loop_filter.initialize(); // initialize the carrier filter
d_code_loop_filter.initialize(); // initialize the code filter
// generate local reference ALWAYS starting at chip 1 (1 sample per chip)
char sig[3];
strcpy(sig,"5Q");
galileo_e5_a_code_gen_complex_primary(&d_codeQ[1], d_acquisition_gnss_synchro->PRN, sig);
d_codeQ[0] = d_codeQ[static_cast<int>(Galileo_E5a_CODE_LENGTH_CHIPS)];
d_codeQ[static_cast<int>(Galileo_E5a_CODE_LENGTH_CHIPS) + 1] = d_codeQ[1];
strcpy(sig,"5I");
galileo_e5_a_code_gen_complex_primary(&d_codeI[1], d_acquisition_gnss_synchro->PRN, sig);
d_codeI[0] = d_codeI[static_cast<int>(Galileo_E5a_CODE_LENGTH_CHIPS)];
d_codeI[static_cast<int>(Galileo_E5a_CODE_LENGTH_CHIPS) + 1] = d_codeI[1];
d_carrier_lock_fail_counter = 0;
d_rem_code_phase_samples = 0;
d_rem_carr_phase_rad = 0;
d_acc_carrier_phase_rad = 0;
d_acc_code_phase_secs = 0;
d_code_phase_samples = d_acq_code_phase_samples;
std::string sys_ = &d_acquisition_gnss_synchro->System;
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) << std::endl;
LOG(INFO) << "Starting tracking of satellite " << Gnss_Satellite(systemName[sys], d_acquisition_gnss_synchro->PRN) << " on channel " << d_channel;
// enable tracking
d_state = 1;
LOG(INFO) << "PULL-IN Doppler [Hz]=" << d_carrier_doppler_hz
<< " Code Phase correction [samples]=" << delay_correction_samples
<< " PULL-IN Code Phase [samples]=" << d_acq_code_phase_samples;
}
void Galileo_E5a_Dll_Pll_Tracking_cc::acquire_secondary()
{
// 1. Transform replica to 1 and -1
int sec_code_signed[Galileo_E5a_Q_SECONDARY_CODE_LENGTH];
for (unsigned int i = 0; i < Galileo_E5a_Q_SECONDARY_CODE_LENGTH; i++)
{
if (Galileo_E5a_Q_SECONDARY_CODE[d_acquisition_gnss_synchro->PRN-1].at(i) == '0')
{
sec_code_signed[i] = 1;
}
else
{
sec_code_signed[i] = -1;
}
}
// 2. Transform buffer to 1 and -1
int in_corr[CN0_ESTIMATION_SAMPLES];
for (unsigned int i = 0; i < CN0_ESTIMATION_SAMPLES; i++)
{
if (d_Prompt_buffer[i].real() >0)
{
in_corr[i] = 1;
}
else
{
in_corr[i] = -1;
}
}
// 3. Serial search
int out_corr;
int current_best_ = 0;
for (unsigned int i = 0; i < Galileo_E5a_Q_SECONDARY_CODE_LENGTH; i++)
{
out_corr = 0;
for (unsigned int j = 0; j < CN0_ESTIMATION_SAMPLES; j++)
{
//reverse replica sign since i*i=-1 (conjugated complex)
out_corr += in_corr[j] * -sec_code_signed[(j+i) % Galileo_E5a_Q_SECONDARY_CODE_LENGTH];
}
if (abs(out_corr) > current_best_)
{
current_best_ = abs(out_corr);
d_secondary_delay = i;
}
}
if (current_best_ == CN0_ESTIMATION_SAMPLES) // all bits correlate
{
d_secondary_lock = true;
d_secondary_delay = (d_secondary_delay + CN0_ESTIMATION_SAMPLES - 1) % Galileo_E5a_Q_SECONDARY_CODE_LENGTH;
}
}
void Galileo_E5a_Dll_Pll_Tracking_cc::update_local_code()
{
double tcode_chips;
double rem_code_phase_chips;
int associated_chip_index;
int associated_chip_index_data;
int code_length_chips = static_cast<int>(Galileo_E5a_CODE_LENGTH_CHIPS);
double code_phase_step_chips;
int early_late_spc_samples;
int epl_loop_length_samples;
// unified loop for E, P, L code vectors
code_phase_step_chips = d_code_freq_chips / static_cast<double>(d_fs_in);
rem_code_phase_chips = d_rem_code_phase_samples * (d_code_freq_chips / d_fs_in);
tcode_chips = -rem_code_phase_chips;
// Alternative EPL code generation (40% of speed improvement!)
early_late_spc_samples = round(d_early_late_spc_chips / code_phase_step_chips);
epl_loop_length_samples = d_current_prn_length_samples + early_late_spc_samples * 2;
for (int i = 0; i < epl_loop_length_samples; i++)
{
associated_chip_index = 1 + round(fmod(tcode_chips - d_early_late_spc_chips, code_length_chips));
associated_chip_index_data = 1 + round(fmod(tcode_chips, code_length_chips));
d_early_code[i] = d_codeQ[associated_chip_index];
d_prompt_data_code[i] = d_codeI[associated_chip_index_data];
tcode_chips = tcode_chips + code_phase_step_chips;
}
memcpy(d_prompt_code, &d_early_code[early_late_spc_samples], d_current_prn_length_samples * sizeof(gr_complex));
memcpy(d_late_code, &d_early_code[early_late_spc_samples * 2], d_current_prn_length_samples * sizeof(gr_complex));
}
void Galileo_E5a_Dll_Pll_Tracking_cc::update_local_carrier()
{
float sin_f, cos_f;
float phase_step_rad = static_cast<float>(2.0 * GALILEO_PI * d_carrier_doppler_hz / static_cast<double>(d_fs_in));
int phase_step_rad_i = gr::fxpt::float_to_fixed(phase_step_rad);
int phase_rad_i = gr::fxpt::float_to_fixed(d_rem_carr_phase_rad);
for(int i = 0; i < d_current_prn_length_samples; i++)
{
gr::fxpt::sincos(phase_rad_i, &sin_f, &cos_f);
d_carr_sign[i] = std::complex<float>(cos_f, -sin_f);
phase_rad_i += phase_step_rad_i;
}
}
int Galileo_E5a_Dll_Pll_Tracking_cc::general_work (int noutput_items, gr_vector_int &ninput_items,
gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
{
// process vars
double carr_error_hz;
double carr_error_filt_hz;
double code_error_chips;
double code_error_filt_chips;
// GNSS_SYNCHRO OBJECT to interchange data between tracking->telemetry_decoder
Gnss_Synchro **out = (Gnss_Synchro **) &output_items[0]; //block output streams pointer
// GNSS_SYNCHRO OBJECT to interchange data between tracking->telemetry_decoder
Gnss_Synchro current_synchro_data;
// Fill the acquisition data
current_synchro_data = *d_acquisition_gnss_synchro;
/* States: 0 Tracking not enabled
* 1 Pull-in of primary code (alignment).
* 3 Tracking algorithm. Correlates EPL each loop and accumulates the result
* until it reaches integration time.
*/
switch (d_state)
{
case 0:
{
// ########## DEBUG OUTPUT (TIME ONLY for channel 0 when tracking is disabled)
/*!
* \todo The stop timer has to be moved to the signal source!
*/
// stream to collect cout calls to improve thread safety
std::stringstream tmp_str_stream;
if (floor(d_sample_counter / d_fs_in) != d_last_seg)
{
d_last_seg = floor(d_sample_counter / d_fs_in);
if (d_channel == 0)
{
// debug: Second counter in channel 0
tmp_str_stream << "Current input signal time = " << d_last_seg << " [s]" << std::endl << std::flush;
std::cout << tmp_str_stream.rdbuf() << std::flush;
}
}
d_Early = gr_complex(0,0);
d_Prompt = gr_complex(0,0);
d_Late = gr_complex(0,0);
d_Prompt_data = gr_complex(0,0);
d_acquisition_gnss_synchro->Flag_valid_pseudorange = false;
*out[0] = *d_acquisition_gnss_synchro;
break;
}
case 1:
{
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);
d_sample_counter = d_sample_counter + samples_offset; //count for the processed samples
DLOG(INFO) << " samples_offset=" << samples_offset;
d_state = 2; // start in Ti = 1 code, until secondary code lock.
// make an output to not stop the rest of the processing blocks
current_synchro_data.Prompt_I = 0.0;
current_synchro_data.Prompt_Q = 0.0;
current_synchro_data.Tracking_timestamp_secs = static_cast<double>(d_sample_counter) / static_cast<double>(d_fs_in);
current_synchro_data.Carrier_phase_rads = 0.0;
current_synchro_data.Code_phase_secs = 0.0;
current_synchro_data.CN0_dB_hz = 0.0;
current_synchro_data.Flag_valid_tracking = false;
current_synchro_data.Flag_valid_pseudorange = false;
*out[0] = current_synchro_data;
consume_each(samples_offset); //shift input to perform alignment with local replica
return 1;
break;
}
case 2:
{
// Block input data and block output stream pointers
const gr_complex* in = (gr_complex*) input_items[0]; //PRN start block alignment
gr_complex sec_sign_Q;
gr_complex sec_sign_I;
// Secondary code Chip
if (d_secondary_lock)
{
// sec_sign_Q = gr_complex((Galileo_E5a_Q_SECONDARY_CODE[d_acquisition_gnss_synchro->PRN-1].at(d_secondary_delay)=='0' ? 1 : -1),0);
// sec_sign_I = gr_complex((Galileo_E5a_I_SECONDARY_CODE.at(d_secondary_delay%Galileo_E5a_I_SECONDARY_CODE_LENGTH)=='0' ? 1 : -1),0);
sec_sign_Q = gr_complex((Galileo_E5a_Q_SECONDARY_CODE[d_acquisition_gnss_synchro->PRN-1].at(d_secondary_delay) == '0' ? -1 : 1), 0);
sec_sign_I = gr_complex((Galileo_E5a_I_SECONDARY_CODE.at(d_secondary_delay % Galileo_E5a_I_SECONDARY_CODE_LENGTH) == '0' ? -1 : 1), 0);
}
else
{
sec_sign_Q = gr_complex(1.0, 0.0);
sec_sign_I = gr_complex(1.0, 0.0);
}
// Reset integration counter
if (d_integration_counter == d_current_ti_ms)
{
d_integration_counter = 0;
}
//Generate local code and carrier replicas (using \hat{f}_d(k-1))
if (d_integration_counter == 0)
{
update_local_code();
update_local_carrier();
// Reset accumulated values
d_Early = gr_complex(0,0);
d_Prompt = gr_complex(0,0);
d_Late = gr_complex(0,0);
}
gr_complex single_early;
gr_complex single_prompt;
gr_complex single_late;
// perform carrier wipe-off and compute Early, Prompt and Late
// correlation of 1 primary code
d_correlator.Carrier_wipeoff_and_EPL_volk_IQ(d_current_prn_length_samples,
in,
d_carr_sign,
d_early_code,
d_prompt_code,
d_late_code,
d_prompt_data_code,
&single_early,
&single_prompt,
&single_late,
&d_Prompt_data);
// Accumulate results (coherent integration since there are no bit transitions in pilot signal)
d_Early += single_early * sec_sign_Q;
d_Prompt += single_prompt * sec_sign_Q;
d_Late += single_late * sec_sign_Q;
d_Prompt_data *= sec_sign_I;
d_integration_counter++;
// check for samples consistency (this should be done before in the receiver / here only if the source is a file)
if (std::isnan((d_Prompt).real()) == true or std::isnan((d_Prompt).imag()) == true ) // or std::isinf(in[i].real())==true or std::isinf(in[i].imag())==true)
{
const int samples_available = ninput_items[0];
d_sample_counter = d_sample_counter + samples_available;
LOG(WARNING) << "Detected NaN samples at sample number " << d_sample_counter;
consume_each(samples_available);
// make an output to not stop the rest of the processing blocks
current_synchro_data.Prompt_I = 0.0;
current_synchro_data.Prompt_Q = 0.0;
current_synchro_data.Tracking_timestamp_secs = static_cast<double>(d_sample_counter) / static_cast<double>(d_fs_in);
current_synchro_data.Carrier_phase_rads = 0.0;
current_synchro_data.Code_phase_secs = 0.0;
current_synchro_data.CN0_dB_hz = 0.0;
current_synchro_data.Flag_valid_tracking = false;
*out[0] = current_synchro_data;
return 1;
}
// ################## PLL ##########################################################
// PLL discriminator
if (d_integration_counter == d_current_ti_ms)
{
if (d_secondary_lock == true)
{
carr_error_hz = pll_four_quadrant_atan(d_Prompt) / GALILEO_PI * 2.0;
}
else
{
carr_error_hz = pll_cloop_two_quadrant_atan(d_Prompt) / GALILEO_PI * 2.0;
}
// 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 = Galileo_E5a_CODE_CHIP_RATE_HZ + ((d_carrier_doppler_hz * Galileo_E5a_CODE_CHIP_RATE_HZ) / Galileo_E5a_FREQ_HZ);
}
//carrier phase accumulator for (K) doppler estimation
d_acc_carrier_phase_rad -= 2*GALILEO_PI * d_carrier_doppler_hz * GALILEO_E5a_CODE_PERIOD;
//remanent carrier phase to prevent overflow in the code NCO
d_rem_carr_phase_rad = d_rem_carr_phase_rad + 2.0*GALILEO_PI * d_carrier_doppler_hz * GALILEO_E5a_CODE_PERIOD;
d_rem_carr_phase_rad = fmod(d_rem_carr_phase_rad, 2.0*GALILEO_PI);
// ################## DLL ##########################################################
if (d_integration_counter == d_current_ti_ms)
{
// DLL discriminator
code_error_chips = dll_nc_e_minus_l_normalized(d_Early, d_Late); //[chips/Ti]
// Code discriminator filter
code_error_filt_chips = d_code_loop_filter.get_code_nco(code_error_chips); //[chips/second]
//Code phase accumulator
d_code_error_filt_secs = (GALILEO_E5a_CODE_PERIOD * code_error_filt_chips) / Galileo_E5a_CODE_CHIP_RATE_HZ; //[seconds]
}
d_acc_code_phase_secs = d_acc_code_phase_secs + d_code_error_filt_secs;
// ################## CARRIER AND CODE NCO BUFFER ALIGNMENT #######################
// keep alignment parameters for the next input buffer
double T_chip_seconds;
double T_prn_seconds;
double T_prn_samples;
double K_blk_samples;
// Compute the next buffer length based in the new period of the PRN sequence and the code phase error estimation
T_chip_seconds = 1.0 / d_code_freq_chips;
T_prn_seconds = T_chip_seconds * Galileo_E5a_CODE_LENGTH_CHIPS;
T_prn_samples = T_prn_seconds * static_cast<double>(d_fs_in);
K_blk_samples = T_prn_samples + d_rem_code_phase_samples + d_code_error_filt_secs * static_cast<double>(d_fs_in);
d_current_prn_length_samples = round(K_blk_samples); //round to a discrete samples
d_rem_code_phase_samples = K_blk_samples - d_current_prn_length_samples; //rounding error < 1 sample
// ####### CN0 ESTIMATION AND LOCK DETECTORS ######
if (d_cn0_estimation_counter < CN0_ESTIMATION_SAMPLES-1)
{
// fill buffer with prompt correlator output values
d_Prompt_buffer[d_cn0_estimation_counter] = d_Prompt;
d_cn0_estimation_counter++;
}
else
{
d_Prompt_buffer[d_cn0_estimation_counter] = d_Prompt;
// ATTEMPT SECONDARY CODE ACQUISITION
if (d_secondary_lock == false)
{
acquire_secondary(); // changes d_secondary_lock and d_secondary_delay
if (d_secondary_lock == true)
{
std::cout << "Secondary code locked." << std::endl;
d_current_ti_ms = d_ti_ms;
// Change loop parameters ==========================================
d_code_loop_filter.set_pdi(d_current_ti_ms * GALILEO_E5a_CODE_PERIOD);
d_carrier_loop_filter.set_pdi(d_current_ti_ms * GALILEO_E5a_CODE_PERIOD);
d_code_loop_filter.set_DLL_BW(d_dll_bw_hz);
d_carrier_loop_filter.set_PLL_BW(d_pll_bw_hz);
}
else
{
std::cout << "Secondary code delay couldn't be resolved." << std::endl;
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 << "!";
std::unique_ptr<ControlMessageFactory> cmf(new ControlMessageFactory());
if (d_queue != gr::msg_queue::sptr())
{
d_queue->handle(cmf->GetQueueMessage(d_channel, 2));
}
d_carrier_lock_fail_counter = 0;
d_state = 0; // TODO: check if disabling tracking is consistent with the channel state machine
}
}
}
else // Secondary lock achieved, monitor carrier lock.
{
// Code lock indicator
d_CN0_SNV_dB_Hz = cn0_svn_estimator(d_Prompt_buffer, CN0_ESTIMATION_SAMPLES, d_fs_in,d_current_ti_ms * Galileo_E5a_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 << "!";
std::unique_ptr<ControlMessageFactory> cmf(new ControlMessageFactory());
if (d_queue != gr::msg_queue::sptr())
{
d_queue->handle(cmf->GetQueueMessage(d_channel, 2));
}
d_carrier_lock_fail_counter = 0;
d_state = 0;
}
}
}
d_cn0_estimation_counter = 0;
}
if (d_secondary_lock && (d_secondary_delay % Galileo_E5a_I_SECONDARY_CODE_LENGTH) == 0)
{
d_first_transition = true;
}
// ########### Output the tracking data to navigation and PVT ##########
// The first Prompt output not equal to 0 is synchronized with the transition of a navigation data bit.
if (d_secondary_lock && d_first_transition)
{
current_synchro_data.Prompt_I = static_cast<double>((d_Prompt_data).real());
current_synchro_data.Prompt_Q = static_cast<double>((d_Prompt_data).imag());
// Tracking_timestamp_secs is aligned with the PRN start sample
current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + static_cast<double>(d_current_prn_length_samples) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
// This tracking block aligns the Tracking_timestamp_secs with the start sample of the PRN, thus, Code_phase_secs=0
current_synchro_data.Code_phase_secs = 0;
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_tracking = false;
// ########## DEBUG OUTPUT
/*!
* \todo The stop timer has to be moved to the signal source!
*/
// debug: Second counter in channel 0
if (d_channel == 0)
{
if (floor(d_sample_counter / d_fs_in) != d_last_seg)
{
d_last_seg = floor(d_sample_counter / d_fs_in);
std::cout << "Current input signal time = " << d_last_seg << " [s]" << std::endl;
std::cout << "Galileo E5 Tracking CH " << d_channel << ": Satellite "
<< Gnss_Satellite(systemName[sys], d_acquisition_gnss_synchro->PRN) << ", CN0 = " << d_CN0_SNV_dB_Hz << " [dB-Hz] "<<"Doppler="<<d_carrier_doppler_hz<<" [Hz]"<< std::endl;
//if (d_last_seg==5) d_carrier_lock_fail_counter=500; //DEBUG: force unlock!
}
}
else
{
if (floor(d_sample_counter / d_fs_in) != d_last_seg)
{
d_last_seg = floor(d_sample_counter / d_fs_in);
std::cout << "Galileo E5 Tracking CH " << d_channel << ": Satellite "
<< Gnss_Satellite(systemName[sys], d_acquisition_gnss_synchro->PRN)
<< ", CN0 = " << d_CN0_SNV_dB_Hz << " [dB-Hz] "<<"Doppler="<<d_carrier_doppler_hz<<" [Hz]"<< std::endl;
//std::cout<<"TRK CH "<<d_channel<<" Carrier_lock_test="<<d_carrier_lock_test<< std::endl;
}
}
}
else
{
// make an output to not stop the rest of the processing blocks
current_synchro_data.Prompt_I = 0.0;
current_synchro_data.Prompt_Q = 0.0;
current_synchro_data.Tracking_timestamp_secs = static_cast<double>(d_sample_counter) / static_cast<double>(d_fs_in);
current_synchro_data.Carrier_phase_rads = 0.0;
current_synchro_data.Code_phase_secs = 0.0;
current_synchro_data.CN0_dB_hz = 0.0;
current_synchro_data.Flag_valid_tracking = false;
// ########## DEBUG OUTPUT (TIME ONLY for channel 0 when tracking is disabled)
/*!
* \todo The stop timer has to be moved to the signal source!
*/
// stream to collect cout calls to improve thread safety
std::stringstream tmp_str_stream;
if (floor(d_sample_counter / d_fs_in) != d_last_seg)
{
d_last_seg = floor(d_sample_counter / d_fs_in);
if (d_channel == 0)
{
// debug: Second counter in channel 0
tmp_str_stream << "Current input signal time = " << d_last_seg << " [s]" << std::endl << std::flush;
std::cout << tmp_str_stream.rdbuf() << std::flush;
}
}
}
*out[0] = current_synchro_data;
break;
}
}
if(d_dump)
{
// MULTIPLEXED FILE RECORDING - Record results to file
float prompt_I;
float prompt_Q;
float tmp_float;
double tmp_double;
prompt_I = (d_Prompt_data).real();
prompt_Q = (d_Prompt_data).imag();
if (d_integration_counter == d_current_ti_ms)
{
tmp_E = std::abs<float>(d_Early);
tmp_P = std::abs<float>(d_Prompt);
tmp_L = std::abs<float>(d_Late);
}
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));
// 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));
//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));
// 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();
}
}
d_secondary_delay = (d_secondary_delay + 1) % Galileo_E5a_Q_SECONDARY_CODE_LENGTH;
d_sample_counter += d_current_prn_length_samples; //count for the processed samples
consume_each(d_current_prn_length_samples); // this is necessary in gr::block derivates
return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false
}
void Galileo_E5a_Dll_Pll_Tracking_cc::set_channel(unsigned int channel)
{
d_channel = channel;
LOG(INFO) << "Tracking Channel set to " << d_channel;
// ############# ENABLE DATA FILE LOG #################
if (d_dump == true)
{
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() << std::endl;
}
catch (std::ifstream::failure e)
{
LOG(WARNING) << "channel " << d_channel << " Exception opening trk dump file " << e.what() << std::endl;
}
}
}
}
void Galileo_E5a_Dll_Pll_Tracking_cc::set_channel_queue(concurrent_queue<int> *channel_internal_queue)
{
d_channel_internal_queue = channel_internal_queue;
}
void Galileo_E5a_Dll_Pll_Tracking_cc::set_gnss_synchro(Gnss_Synchro* p_gnss_synchro)
{
d_acquisition_gnss_synchro = p_gnss_synchro;
}
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