mirror of https://github.com/gnss-sdr/gnss-sdr
141 lines
6.0 KiB
C++
141 lines
6.0 KiB
C++
/*!
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* \file galileo_e5_signal_processing.cc
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* \brief This library implements various functions for Galileo E5 signals such
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* as replica code generation
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* \author Marc Sales, 2014. marcsales92(at)gmail.com
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*
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* Detailed description of the file here if needed.
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*
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* -------------------------------------------------------------------------
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*
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* Copyright (C) 2010-2015 (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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#include "galileo_e5_signal_processing.h"
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#include "Galileo_E5a.h"
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#include "gnss_signal_processing.h"
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#include <gnuradio/gr_complex.h>
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void galileo_e5_a_code_gen_complex_primary(std::complex<float>* _dest, signed int _prn, char _Signal[3])
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{
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unsigned int prn = _prn - 1;
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unsigned int index = 0;
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int a[4];
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if ((_prn < 1) || (_prn > 50))
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{
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return;
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}
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if (_Signal[0] == '5' && _Signal[1] == 'Q')
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{
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for (size_t i = 0; i < Galileo_E5a_Q_PRIMARY_CODE[prn].length() - 1; i++)
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{
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hex_to_binary_converter(a, Galileo_E5a_Q_PRIMARY_CODE[prn].at(i));
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_dest[index] = std::complex<float>(0.0, float(a[0]));
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_dest[index + 1] = std::complex<float>(0.0, float(a[1]));
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_dest[index + 2] = std::complex<float>(0.0, float(a[2]));
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_dest[index + 3] = std::complex<float>(0.0, float(a[3]));
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index = index + 4;
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}
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// last 2 bits are filled up zeros
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hex_to_binary_converter(a, Galileo_E5a_Q_PRIMARY_CODE[prn].at(Galileo_E5a_Q_PRIMARY_CODE[prn].length() - 1));
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_dest[index] = std::complex<float>(float(0.0), a[0]);
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_dest[index + 1] = std::complex<float>(float(0.0), a[1]);
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}
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else if (_Signal[0] == '5' && _Signal[1] == 'I')
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{
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for (size_t i = 0; i < Galileo_E5a_I_PRIMARY_CODE[prn].length() - 1; i++)
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{
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hex_to_binary_converter(a, Galileo_E5a_I_PRIMARY_CODE[prn].at(i));
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_dest[index] = std::complex<float>(float(a[0]), 0.0);
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_dest[index + 1] = std::complex<float>(float(a[1]), 0.0);
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_dest[index + 2] = std::complex<float>(float(a[2]), 0.0);
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_dest[index + 3] = std::complex<float>(float(a[3]), 0.0);
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index = index + 4;
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}
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// last 2 bits are filled up zeros
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hex_to_binary_converter(a, Galileo_E5a_I_PRIMARY_CODE[prn].at(Galileo_E5a_I_PRIMARY_CODE[prn].length() - 1));
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_dest[index] = std::complex<float>(float(a[0]), 0.0);
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_dest[index + 1] = std::complex<float>(float(a[1]), 0.0);
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}
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else if (_Signal[0] == '5' && _Signal[1] == 'X')
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{
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int b[4];
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for (size_t i = 0; i < Galileo_E5a_I_PRIMARY_CODE[prn].length() - 1; i++)
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{
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hex_to_binary_converter(a, Galileo_E5a_I_PRIMARY_CODE[prn].at(i));
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hex_to_binary_converter(b, Galileo_E5a_Q_PRIMARY_CODE[prn].at(i));
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_dest[index] = std::complex<float>(float(a[0]),float(b[0]));
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_dest[index + 1] = std::complex<float>(float(a[1]),float(b[1]));
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_dest[index + 2] = std::complex<float>(float(a[2]),float(b[2]));
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_dest[index + 3] = std::complex<float>(float(a[3]),float(b[3]));
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index = index + 4;
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}
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// last 2 bits are filled up zeros
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hex_to_binary_converter(a, Galileo_E5a_I_PRIMARY_CODE[prn].at(Galileo_E5a_I_PRIMARY_CODE[prn].length() - 1));
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hex_to_binary_converter(b, Galileo_E5a_Q_PRIMARY_CODE[prn].at(Galileo_E5a_Q_PRIMARY_CODE[prn].length() - 1));
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_dest[index] = std::complex<float>(float(a[0]), float(b[0]));
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_dest[index + 1] = std::complex<float>(float(a[1]), float(b[1]));
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}
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}
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void galileo_e5_a_code_gen_complex_sampled(std::complex<float>* _dest, char _Signal[3],
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unsigned int _prn, signed int _fs, unsigned int _chip_shift)
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{
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unsigned int _samplesPerCode;
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unsigned int delay;
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const unsigned int _codeLength = Galileo_E5a_CODE_LENGTH_CHIPS;
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const int _codeFreqBasis = Galileo_E5a_CODE_CHIP_RATE_HZ;
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std::complex<float>* _code = new std::complex<float>[_codeLength]();
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galileo_e5_a_code_gen_complex_primary(_code , _prn , _Signal);
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_samplesPerCode = static_cast<unsigned int>(static_cast<double>(_fs) / ( static_cast<double>(_codeFreqBasis) / static_cast<double>(_codeLength)));
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delay = ((_codeLength - _chip_shift) % _codeLength) * _samplesPerCode / _codeLength;
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if (_fs != _codeFreqBasis)
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{
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std::complex<float>* _resampled_signal;
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if (posix_memalign((void**)&_resampled_signal, 16, _samplesPerCode * sizeof(gr_complex)) == 0){};
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resampler(_code, _resampled_signal, _codeFreqBasis, _fs, _codeLength, _samplesPerCode); //resamples code to fs
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delete[] _code;
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_code = _resampled_signal;
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}
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for (unsigned int i = 0; i < _samplesPerCode; i++)
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{
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_dest[(i + delay) % _samplesPerCode] = _code[i];
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}
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if (_fs != _codeFreqBasis)
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{
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free(_code);
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}
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else
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{
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delete[] _code;
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}
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}
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