mirror of https://github.com/gnss-sdr/gnss-sdr
137 lines
6.2 KiB
C++
137 lines
6.2 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) 2010-2018 (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 <https://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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#include <memory>
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void galileo_e5_a_code_gen_complex_primary(gsl::span<std::complex<float>> _dest, int32_t _prn, const std::array<char, 3>& _Signal)
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{
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uint32_t prn = _prn - 1;
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uint32_t index = 0;
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int32_t 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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int32_t 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(gsl::span<std::complex<float>> _dest, const std::array<char, 3>& _Signal,
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uint32_t _prn, int32_t _fs, uint32_t _chip_shift)
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{
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uint32_t _samplesPerCode;
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uint32_t delay;
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const uint32_t _codeLength = GALILEO_E5A_CODE_LENGTH_CHIPS;
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const int32_t _codeFreqBasis = GALILEO_E5A_CODE_CHIP_RATE_HZ;
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std::unique_ptr<std::complex<float>> _code{new std::complex<float>[_codeLength]};
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gsl::span<std::complex<float>> _code_span(_code, _codeLength);
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galileo_e5_a_code_gen_complex_primary(_code_span, _prn, _Signal);
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_samplesPerCode = static_cast<uint32_t>(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::unique_ptr<std::complex<float>> _resampled_signal{new std::complex<float>[_samplesPerCode]};
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resampler(_code_span, gsl::span<std::complex<float>>(_resampled_signal, _samplesPerCode), _codeFreqBasis, _fs); // resamples code to fs
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_code = std::move(_resampled_signal);
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}
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uint32_t size_code = _codeLength;
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if (_fs != _codeFreqBasis)
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{
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size_code = _samplesPerCode;
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}
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gsl::span<std::complex<float>> _code_span_aux(_code, size_code);
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for (uint32_t i = 0; i < _samplesPerCode; i++)
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{
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_dest[(i + delay) % _samplesPerCode] = _code_span_aux[i];
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}
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}
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