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* \file pcps_acquisition.h
* \brief This class implements a Parallel Code Phase Search Acquisition
* Acquisition strategy (Kay Borre book + CFAR threshold).
* <ol>
* <li> Compute the input signal power estimation
* <li> Doppler serial search loop
* <li> Perform the FFT-based circular convolution (parallel time search)
* <li> Record the maximum peak and the associated synchronization parameters
* <li> Compute the test statistics and compare to the threshold
* <li> Declare positive or negative acquisition using a message queue
* </ol>
* Kay Borre book: K.Borre, D.M.Akos, N.Bertelsen, P.Rinder, and S.H.Jensen,
* "A Software-Defined GPS and Galileo Receiver. A Single-Frequency
* Approach", Birkhauser, 2007. pp 81-84
* \authors <ul>
* <li> Javier Arribas, 2011. jarribas(at)
* <li> Luis Esteve, 2012. luis(at)
* <li> Marc Molina, 2013.
* <li> Cillian O'Driscoll, 2017. cillian(at)
* <li> Antonio Ramos, 2017.
* </ul>
* -------------------------------------------------------------------------
* Copyright (C) 2010-2019 (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
* 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 <>.
* -------------------------------------------------------------------------
#define ARMA_NO_DEBUG 1
#include "acq_conf.h"
#include "channel_fsm.h"
#include <armadillo>
#include <glog/logging.h>
#include <gnuradio/block.h>
#include <gnuradio/fft/fft.h>
#include <gnuradio/gr_complex.h> // for gr_complex
#include <gnuradio/thread/thread.h> // for scoped_lock
#include <gnuradio/types.h> // for gr_vector_const_void_star
#include <gsl/gsl> // for Guidelines Support Library
#include <volk/volk_complex.h> // for lv_16sc_t
#include <complex>
#include <cstdint>
#include <memory>
#include <string>
#include <utility>
#include <vector>
class Gnss_Synchro;
class pcps_acquisition;
using pcps_acquisition_sptr = boost::shared_ptr<pcps_acquisition>;
pcps_acquisition_sptr pcps_make_acquisition(const Acq_Conf& conf_);
* \brief This class implements a Parallel Code Phase Search Acquisition.
* Check \ref Navitec2012 "An Open Source Galileo E1 Software Receiver",
* Algorithm 1, for a pseudocode description of this implementation.
class pcps_acquisition : public gr::block
~pcps_acquisition() = default;
* \brief Set acquisition/tracking common Gnss_Synchro object pointer
* to exchange synchronization data between acquisition and tracking blocks.
* \param p_gnss_synchro Satellite information shared by the processing blocks.
inline void set_gnss_synchro(Gnss_Synchro* p_gnss_synchro)
gr::thread::scoped_lock lock(d_setlock); // require mutex with work function called by the scheduler
d_gnss_synchro = p_gnss_synchro;
* \brief Returns the maximum peak of grid search.
inline uint32_t mag() const
return d_mag;
* \brief Initializes acquisition algorithm and reserves memory.
void init();
* \brief Sets local code for PCPS acquisition algorithm.
* \param code - Pointer to the PRN code.
void set_local_code(std::complex<float>* code);
* \brief Starts acquisition algorithm, turning from standby mode to
* active mode
* \param active - bool that activates/deactivates the block.
inline void set_active(bool active)
gr::thread::scoped_lock lock(d_setlock); // require mutex with work function called by the scheduler
d_active = active;
* \brief If set to 1, ensures that acquisition starts at the
* first available sample.
* \param state - int=1 forces start of acquisition
void set_state(int32_t state);
* \brief Set acquisition channel unique ID
* \param channel - receiver channel.
inline void set_channel(uint32_t channel)
d_channel = channel;
* \brief Set channel fsm associated to this acquisition instance
inline void set_channel_fsm(std::weak_ptr<ChannelFsm> channel_fsm)
d_channel_fsm = std::move(channel_fsm);
* \brief Set statistics threshold of PCPS algorithm.
* \param threshold - Threshold for signal detection (check \ref Navitec2012,
* Algorithm 1, for a definition of this threshold).
inline void set_threshold(float threshold)
gr::thread::scoped_lock lock(d_setlock); // require mutex with work function called by the scheduler
d_threshold = threshold;
* \brief Set maximum Doppler grid search
* \param doppler_max - Maximum Doppler shift considered in the grid search [Hz].
inline void set_doppler_max(uint32_t doppler_max)
gr::thread::scoped_lock lock(d_setlock); // require mutex with work function called by the scheduler
acq_parameters.doppler_max = doppler_max;
* \brief Set Doppler steps for the grid search
* \param doppler_step - Frequency bin of the search grid [Hz].
inline void set_doppler_step(uint32_t doppler_step)
gr::thread::scoped_lock lock(d_setlock); // require mutex with work function called by the scheduler
d_doppler_step = doppler_step;
* \brief Set Doppler center frequency for the grid search. It will refresh the Doppler grid.
* \param doppler_center - Frequency center of the search grid [Hz].
inline void set_doppler_center(int32_t doppler_center)
gr::thread::scoped_lock lock(d_setlock); // require mutex with work function called by the scheduler
if (doppler_center != d_doppler_center)
DLOG(INFO) << " Doppler assistance for Channel: " << d_channel << " => Doppler: " << doppler_center << "[Hz]";
d_doppler_center = doppler_center;
void set_resampler_latency(uint32_t latency_samples);
* \brief Parallel Code Phase Search Acquisition signal processing.
int general_work(int noutput_items, gr_vector_int& ninput_items,
gr_vector_const_void_star& input_items,
gr_vector_void_star& output_items);
friend pcps_acquisition_sptr pcps_make_acquisition(const Acq_Conf& conf_);
pcps_acquisition(const Acq_Conf& conf_);
bool d_active;
bool d_worker_active;
bool d_cshort;
bool d_step_two;
bool d_use_CFAR_algorithm_flag;
bool d_dump;
int32_t d_state;
int32_t d_positive_acq;
uint32_t d_channel;
uint32_t d_samplesPerChip;
uint32_t d_doppler_step;
int32_t d_doppler_center;
int32_t d_doppler_bias;
uint32_t d_num_noncoherent_integrations_counter;
uint32_t d_fft_size;
uint32_t d_consumed_samples;
uint32_t d_num_doppler_bins;
uint32_t d_num_doppler_bins_step2;
uint32_t d_dump_channel;
uint32_t d_buffer_count;
uint64_t d_sample_counter;
int64_t d_dump_number;
float d_threshold;
float d_mag;
float d_input_power;
float d_test_statistics;
float d_doppler_center_step_two;
std::string d_dump_filename;
std::vector<std::vector<float>> d_magnitude_grid;
std::vector<float> d_tmp_buffer;
std::vector<std::complex<float>> d_input_signal;
std::vector<std::vector<std::complex<float>>> d_grid_doppler_wipeoffs;
std::vector<std::vector<std::complex<float>>> d_grid_doppler_wipeoffs_step_two;
std::vector<std::complex<float>> d_fft_codes;
std::vector<std::complex<float>> d_data_buffer;
std::vector<lv_16sc_t> d_data_buffer_sc;
std::shared_ptr<gr::fft::fft_complex> d_fft_if;
std::shared_ptr<gr::fft::fft_complex> d_ifft;
std::weak_ptr<ChannelFsm> d_channel_fsm;
Acq_Conf acq_parameters;
Gnss_Synchro* d_gnss_synchro;
arma::fmat grid_;
arma::fmat narrow_grid_;
void update_local_carrier(gsl::span<gr_complex> carrier_vector, float freq);
void update_grid_doppler_wipeoffs();
void update_grid_doppler_wipeoffs_step2();
void acquisition_core(uint64_t samp_count);
void send_negative_acquisition();
void send_positive_acquisition();
void dump_results(int32_t effective_fft_size);
bool is_fdma();
bool start();
float first_vs_second_peak_statistic(uint32_t& indext, int32_t& doppler, uint32_t num_doppler_bins, int32_t doppler_max, int32_t doppler_step);
float max_to_input_power_statistic(uint32_t& indext, int32_t& doppler, float input_power, uint32_t num_doppler_bins, int32_t doppler_max, int32_t doppler_step);
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