mirror of https://github.com/gnss-sdr/gnss-sdr
254 lines
7.4 KiB
C++
254 lines
7.4 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) 2010-2020 (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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* SPDX-License-Identifier: GPL-3.0-or-later
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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 "channel_fsm.h"
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#include "gnss_synchro.h"
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#include <gnuradio/block.h>
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#include <gnuradio/fft/fft.h>
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#include <gnuradio/gr_complex.h>
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#include <fstream>
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#include <memory> // for weak_ptr
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#include <string>
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#include <utility>
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#include <vector>
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#if GNURADIO_USES_STD_POINTERS
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#else
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#include <boost/shared_ptr.hpp>
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#endif
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class pcps_tong_acquisition_cc;
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#if GNURADIO_USES_STD_POINTERS
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using pcps_tong_acquisition_cc_sptr = std::shared_ptr<pcps_tong_acquisition_cc>;
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#else
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using pcps_tong_acquisition_cc_sptr = boost::shared_ptr<pcps_tong_acquisition_cc>;
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#endif
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pcps_tong_acquisition_cc_sptr pcps_tong_make_acquisition_cc(
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uint32_t sampled_ms,
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uint32_t doppler_max,
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int64_t fs_in,
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int32_t samples_per_ms,
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int32_t samples_per_code,
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uint32_t tong_init_val,
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uint32_t tong_max_val,
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uint32_t tong_max_dwells,
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bool dump,
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const std::string& dump_filename,
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bool enable_monitor_output);
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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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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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inline 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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inline uint32_t mag() const
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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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inline 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 If set to 1, ensures that acquisition starts at the
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* first available sample.
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* \param state - int=1 forces start of acquisition
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*/
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void set_state(int32_t state);
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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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inline void set_channel(uint32_t 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 channel fsm associated to this acquisition instance
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*/
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inline void set_channel_fsm(std::weak_ptr<ChannelFsm> channel_fsm)
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{
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d_channel_fsm = std::move(channel_fsm);
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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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inline 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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inline void set_doppler_max(uint32_t 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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inline void set_doppler_step(uint32_t 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 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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private:
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friend pcps_tong_acquisition_cc_sptr
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pcps_tong_make_acquisition_cc(uint32_t sampled_ms, uint32_t doppler_max,
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int64_t fs_in, int32_t samples_per_ms,
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int32_t samples_per_code, uint32_t tong_init_val,
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uint32_t tong_max_val, uint32_t tong_max_dwells,
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bool dump, const std::string& dump_filename, bool enable_monitor_output);
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pcps_tong_acquisition_cc(uint32_t sampled_ms, uint32_t doppler_max,
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int64_t fs_in, int32_t samples_per_ms,
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int32_t samples_per_code, uint32_t tong_init_val,
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uint32_t tong_max_val, uint32_t tong_max_dwells,
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bool dump, const std::string& dump_filename, bool enable_monitor_output);
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void calculate_magnitudes(gr_complex* fft_begin, int32_t doppler_shift,
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int32_t doppler_offset);
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std::weak_ptr<ChannelFsm> d_channel_fsm;
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std::unique_ptr<gr::fft::fft_complex> d_fft_if;
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std::unique_ptr<gr::fft::fft_complex> d_ifft;
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std::vector<std::vector<gr_complex>> d_grid_doppler_wipeoffs;
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std::vector<std::vector<float>> d_grid_data;
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std::vector<gr_complex> d_fft_codes;
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std::vector<float> d_magnitude;
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std::string d_satellite_str;
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std::string d_dump_filename;
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std::ofstream d_dump_file;
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Gnss_Synchro* d_gnss_synchro;
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int64_t d_fs_in;
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uint64_t d_sample_counter;
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float d_threshold;
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float d_doppler_freq;
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float d_mag;
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float d_input_power;
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float d_test_statistics;
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int32_t d_state;
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int32_t d_samples_per_ms;
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int32_t d_samples_per_code;
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uint32_t d_channel;
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uint32_t d_doppler_resolution;
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uint32_t d_doppler_max;
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uint32_t d_doppler_step;
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uint32_t d_sampled_ms;
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uint32_t d_dwell_count;
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uint32_t d_tong_count;
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uint32_t d_tong_init_val;
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uint32_t d_tong_max_val;
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uint32_t d_tong_max_dwells;
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uint32_t d_fft_size;
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uint32_t d_num_doppler_bins;
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uint32_t d_code_phase;
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bool d_active;
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bool d_dump;
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bool d_enable_monitor_output;
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};
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#endif // GNSS_SDR_PCPS_TONG_ACQUISITION_CC_H
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