mirror of https://github.com/gnss-sdr/gnss-sdr
240 lines
7.7 KiB
C++
240 lines
7.7 KiB
C++
/*!
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* \file pcps_tong_acquisition_cc.h
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* \brief This class implements a Parallel Code Phase Search Acquisition with
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* Tong algorithm.
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* \author Marc Molina, 2013. marc.molina.pena(at)gmail.com
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*
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* Acquisition strategy (Kaplan book + CFAR threshold).
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* <ol>
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* <li> Compute the input signal power estimation.
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* <li> Doppler serial search loop.
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* <li> Perform the FFT-based circular convolution (parallel time search).
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* <li> Compute the tests statistics for all the cells.
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* <li> Accumulate the grid of tests statistics with the previous grids.
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* <li> Record the maximum peak and the associated synchronization parameters.
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* <li> Compare the maximum averaged test statistics with a threshold.
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* <li> If the test statistics exceeds the threshold, increment the Tong counter.
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* <li> Otherwise, decrement the Tong counter.
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* <li> If the Tong counter is equal to a given maximum value, declare positive
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* <li> acquisition. If the Tong counter is equa to zero, declare negative
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* <li> acquisition. Otherwise, process the next block.
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* </ol>
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*
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* Kaplan book: D.Kaplan, J.Hegarty, "Understanding GPS. Principles
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* and Applications", Artech House, 2006, pp 223-227
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*
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* -------------------------------------------------------------------------
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*
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* Copyright (C) 2010-2012 (see AUTHORS file for a list of contributors)
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*
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* GNSS-SDR is a software defined Global Navigation
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* Satellite Systems receiver
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*
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* This file is part of GNSS-SDR.
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*
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* GNSS-SDR is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* at your option) any later version.
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*
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* GNSS-SDR is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNSS-SDR. If not, see <http://www.gnu.org/licenses/>.
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*
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* -------------------------------------------------------------------------
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*/
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#ifndef GNSS_SDR_PCPS_TONG_acquisition_cc_H_
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#define GNSS_SDR_PCPS_TONG_acquisition_cc_H_
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#include <fstream>
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#include <gnuradio/block.h>
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#include <gnuradio/msg_queue.h>
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#include <gnuradio/gr_complex.h>
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#include <gnuradio/fft/fft.h>
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#include <queue>
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#include <boost/thread/mutex.hpp>
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#include <boost/thread/thread.hpp>
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#include "concurrent_queue.h"
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#include "gnss_synchro.h"
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class pcps_tong_acquisition_cc;
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typedef boost::shared_ptr<pcps_tong_acquisition_cc> pcps_tong_acquisition_cc_sptr;
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pcps_tong_acquisition_cc_sptr
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pcps_tong_make_acquisition_cc(unsigned int sampled_ms, unsigned int doppler_max,
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long freq, long fs_in, int samples_per_ms,
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int samples_per_code, unsigned int tong_init_val,
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unsigned int tong_max_val, gr::msg_queue::sptr queue,
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bool dump, std::string dump_filename);
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/*!
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* \brief This class implements a Parallel Code Phase Search Acquisition with
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* Tong algorithm.
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*/
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class pcps_tong_acquisition_cc: public gr::block
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{
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private:
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friend pcps_tong_acquisition_cc_sptr
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pcps_tong_make_acquisition_cc(unsigned int sampled_ms, unsigned int doppler_max,
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long freq, long fs_in, int samples_per_ms,
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int samples_per_code, unsigned int tong_init_val,
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unsigned int tong_max_val, gr::msg_queue::sptr queue,
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bool dump, std::string dump_filename);
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pcps_tong_acquisition_cc(unsigned int sampled_ms, unsigned int doppler_max,
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long freq, long fs_in, int samples_per_ms,
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int samples_per_code, unsigned int tong_init_val,
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unsigned int tong_max_val, gr::msg_queue::sptr queue,
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bool dump, std::string dump_filename);
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void calculate_magnitudes(gr_complex* fft_begin, int doppler_shift,
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int doppler_offset);
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long d_fs_in;
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long d_freq;
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int d_samples_per_ms;
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int d_samples_per_code;
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unsigned int d_doppler_resolution;
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float d_threshold;
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std::string d_satellite_str;
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unsigned int d_doppler_max;
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unsigned int d_doppler_step;
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unsigned int d_sampled_ms;
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unsigned int d_well_count;
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unsigned int d_tong_count;
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unsigned int d_tong_init_val;
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unsigned int d_tong_max_val;
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unsigned int d_fft_size;
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unsigned long int d_sample_counter;
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gr_complex** d_grid_doppler_wipeoffs;
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unsigned int d_num_doppler_bins;
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gr_complex* d_fft_codes;
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float** d_grid_data;
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gr::fft::fft_complex* d_fft_if;
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gr::fft::fft_complex* d_ifft;
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Gnss_Synchro *d_gnss_synchro;
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unsigned int d_code_phase;
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float d_doppler_freq;
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float d_mag;
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float* d_magnitude;
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float d_input_power;
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float d_test_statistics;
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gr::msg_queue::sptr d_queue;
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concurrent_queue<int> *d_channel_internal_queue;
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std::ofstream d_dump_file;
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bool d_active;
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int d_state;
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bool d_dump;
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unsigned int d_channel;
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std::string d_dump_filename;
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public:
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/*!
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* \brief Default destructor.
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*/
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~pcps_tong_acquisition_cc();
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/*!
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* \brief Set acquisition/tracking common Gnss_Synchro object pointer
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* to exchange synchronization data between acquisition and tracking blocks.
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* \param p_gnss_synchro Satellite information shared by the processing blocks.
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*/
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void set_gnss_synchro(Gnss_Synchro* p_gnss_synchro)
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{
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d_gnss_synchro = p_gnss_synchro;
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}
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/*!
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* \brief Returns the maximum peak of grid search.
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*/
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unsigned int mag()
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{
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return d_mag;
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}
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/*!
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* \brief Initializes acquisition algorithm.
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*/
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void init();
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/*!
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* \brief Sets local code for TONG acquisition algorithm.
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* \param code - Pointer to the PRN code.
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*/
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void set_local_code(std::complex<float> * code);
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/*!
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* \brief Starts acquisition algorithm, turning from standby mode to
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* active mode
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* \param active - bool that activates/deactivates the block.
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*/
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void set_active(bool active)
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{
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d_active = active;
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}
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/*!
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* \brief Set acquisition channel unique ID
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* \param channel - receiver channel.
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*/
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void set_channel(unsigned int channel)
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{
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d_channel = channel;
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}
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/*!
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* \brief Set statistics threshold of TONG algorithm.
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* \param threshold - Threshold for signal detection (check \ref Navitec2012,
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* Algorithm 1, for a definition of this threshold).
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*/
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void set_threshold(float threshold)
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{
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d_threshold = threshold;
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}
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/*!
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* \brief Set maximum Doppler grid search
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* \param doppler_max - Maximum Doppler shift considered in the grid search [Hz].
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*/
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void set_doppler_max(unsigned int doppler_max)
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{
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d_doppler_max = doppler_max;
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}
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/*!
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* \brief Set Doppler steps for the grid search
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* \param doppler_step - Frequency bin of the search grid [Hz].
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*/
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void set_doppler_step(unsigned int doppler_step)
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{
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d_doppler_step = doppler_step;
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}
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/*!
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* \brief Set tracking channel internal queue.
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* \param channel_internal_queue - Channel's internal blocks information queue.
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*/
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void set_channel_queue(concurrent_queue<int> *channel_internal_queue)
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{
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d_channel_internal_queue = channel_internal_queue;
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}
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/*!
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* \brief Parallel Code Phase Search Acquisition signal processing.
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*/
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int general_work(int noutput_items, gr_vector_int &ninput_items,
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gr_vector_const_void_star &input_items,
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gr_vector_void_star &output_items);
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};
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#endif /* GNSS_SDR_PCPS_TONG_acquisition_cc_H_ */
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