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gnss-sdr/src/algorithms/acquisition/gnuradio_blocks/pcps_quicksync_acquisition_...

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/*!
* \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).
* <ol>
* <li> Compute the input signal power estimation
* <li> Doppler serial search loop
* <li> Perform folding of the incoming signal and local generated code
* <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 port
* <li> Obtain the adequate acquisition parameters by correlating the incoming
* signal shifted by the possible folded delays
* </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", 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 <http://www.gnu.org/licenses/>.
*
* -------------------------------------------------------------------------
*/
#ifndef GNSS_SDR_PCPS_QUICKSYNC_ACQUISITION_CC_H_
#define GNSS_SDR_PCPS_QUICKSYNC_ACQUISITION_CC_H_
#include <fstream>
#include <string>
#include <algorithm>
#include <functional>
#include <assert.h>
#include <gnuradio/block.h>
#include <gnuradio/gr_complex.h>
#include <gnuradio/fft/fft.h>
#include "gnss_synchro.h"
class pcps_quicksync_acquisition_cc;
typedef boost::shared_ptr<pcps_quicksync_acquisition_cc>
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<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)
{
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_*/
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