/*! * \file pcps_quicksync_acquisition_cc.h * \brief This class implements a Parallel Code Phase Search Acquisition with the * QuickSync Algorithm * * Acquisition strategy (Kay Borre book CFAR + threshold). *
    *
  1. Compute the input signal power estimation *
  2. Doppler serial search loop *
  3. Perform folding of the incoming signal and local generated code *
  4. Perform the FFT-based circular convolution (parallel time search) *
  5. Record the maximum peak and the associated synchronization parameters *
  6. Compute the test statistics and compare to the threshold *
  7. Declare positive or negative acquisition using a message port *
  8. Obtain the adequate acquisition parameters by correlating the incoming * signal shifted by the possible folded delays *
* * 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", Birkha user, 2007. pp 81-84 * * \date Jun2 2014 * \author Damian Miralles Sanchez, dmiralles2009@gmail.com * * ------------------------------------------------------------------------- * * 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 . * * ------------------------------------------------------------------------- */ #ifndef GNSS_SDR_PCPS_QUICKSYNC_ACQUISITION_CC_H_ #define GNSS_SDR_PCPS_QUICKSYNC_ACQUISITION_CC_H_ #include #include #include #include #include #include #include #include #include "gnss_synchro.h" class pcps_quicksync_acquisition_cc; typedef boost::shared_ptr pcps_quicksync_acquisition_cc_sptr; pcps_quicksync_acquisition_cc_sptr pcps_quicksync_make_acquisition_cc(unsigned int folding_factor, unsigned int sampled_ms, unsigned int max_dwells, unsigned int doppler_max, long freq, long fs_in, int samples_per_ms, int samples_per_code, bool bit_transition_flag, bool dump, std::string dump_filename); /*! * \brief This class implements a Parallel Code Phase Search Acquisition with * the implementation of the Sparse QuickSync Algorithm. * * Check \ref Navitec2012 "Faster GPS via the Sparse Fourier Transform", * for details of its implementation and functionality. */ class pcps_quicksync_acquisition_cc: public gr::block { private: friend pcps_quicksync_acquisition_cc_sptr pcps_quicksync_make_acquisition_cc(unsigned int folding_factor, unsigned int sampled_ms, unsigned int max_dwells, unsigned int doppler_max, long freq, long fs_in, int samples_per_ms, int samples_per_code, bool bit_transition_flag, bool dump, std::string dump_filename); pcps_quicksync_acquisition_cc(unsigned int folding_factor, unsigned int sampled_ms, unsigned int max_dwells, unsigned int doppler_max, long freq, long fs_in, int samples_per_ms, int samples_per_code, bool bit_transition_flag, bool dump, std::string dump_filename); void calculate_magnitudes(gr_complex* fft_begin, int doppler_shift, int doppler_offset); gr_complex* d_code; unsigned int d_folding_factor; // also referred in the paper as 'p' float* d_corr_acumulator; unsigned int* d_possible_delay; float* d_corr_output_f; float* d_magnitude_folded; gr_complex* d_signal_folded; gr_complex* d_code_folded; float d_noise_floor_power; long d_fs_in; long d_freq; int d_samples_per_ms; int d_samples_per_code; unsigned int d_doppler_resolution; float d_threshold; std::string d_satellite_str; unsigned int d_doppler_max; unsigned int d_doppler_step; unsigned int d_sampled_ms; unsigned int d_max_dwells; unsigned int d_well_count; unsigned int d_fft_size; unsigned long int d_sample_counter; gr_complex** d_grid_doppler_wipeoffs; unsigned int d_num_doppler_bins; gr_complex* d_fft_codes; gr::fft::fft_complex* d_fft_if; gr::fft::fft_complex* d_fft_if2; gr::fft::fft_complex* d_ifft; Gnss_Synchro *d_gnss_synchro; unsigned int d_code_phase; float d_doppler_freq; float d_mag; float* d_magnitude; float d_input_power; float d_test_statistics; bool d_bit_transition_flag; std::ofstream d_dump_file; bool d_active; int d_state; bool d_dump; unsigned int d_channel; std::string d_dump_filename; public: /*! * \brief Default destructor. */ ~pcps_quicksync_acquisition_cc(); /*! * \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) { d_gnss_synchro = p_gnss_synchro; } /*! * \brief Returns the maximum peak of grid search. */ inline unsigned int mag() const { return d_mag; } /*! * \brief Initializes acquisition algorithm. */ void init(); /*! * \brief Sets local code for PCPS acquisition algorithm. * \param code - Pointer to the PRN code. */ void set_local_code(std::complex * 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) { 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(int state); /*! * \brief Set acquisition channel unique ID * \param channel - receiver channel. */ inline void set_channel(unsigned int channel) { d_channel = channel; } /*! * \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) { 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(unsigned int doppler_max) { d_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(unsigned int doppler_step) { d_doppler_step = doppler_step; } /*! * \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); }; #endif /* GNSS_SDR_PCPS_ACQUISITION_CC_H_*/