mirror of https://github.com/gnss-sdr/gnss-sdr
198 lines
7.0 KiB
C++
198 lines
7.0 KiB
C++
/*!
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* \file galileo_e1_signal_processing.cc
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* \brief This library implements various functions for Galileo E1 signals
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* \author Luis Esteve, 2012. luis(at)epsilon-formacion.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) 2010-2012 (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_e1_signal_processing.h"
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void
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galileo_e1_code_gen_int(int* _dest, char _Signal[3], signed int _prn,
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unsigned int _chip_shift)
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{
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std::string _galileo_signal = _Signal;
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signed int prn = _prn - 1;
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int index = 0;
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//int* dest = _dest;
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/* A simple error check */
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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 (_galileo_signal.rfind("1B") != std::string::npos && _galileo_signal.length() >= 2)
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{
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for (size_t i = 0; i < Galileo_E1_B_PRIMARY_CODE[prn].length(); i++)
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{
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hex_to_binary_converter(&_dest[index],
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Galileo_E1_B_PRIMARY_CODE[prn].at(i));
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index = index +4;
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}
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}
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else if (_galileo_signal.rfind("1C") != std::string::npos && _galileo_signal.length() >= 2)
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{
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for (size_t i = 0; i < Galileo_E1_C_PRIMARY_CODE[prn].length(); i++)
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{
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hex_to_binary_converter(&_dest[index],
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Galileo_E1_C_PRIMARY_CODE[prn].at(i));
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index = index +4;
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}
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}
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else
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{
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return;
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}
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}
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void
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galileo_e1_sinboc_11_gen(std::complex<float>* _dest, int* _prn,
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unsigned int _length_out)
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{
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const unsigned int _length_in = Galileo_E1_B_CODE_LENGTH_CHIPS;
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unsigned int _period = (unsigned int) (_length_out / _length_in);
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for (unsigned int i = 0; i < _length_in; i++)
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{
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for (unsigned int j = 0; j < (_period / 2); j++)
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_dest[i * _period + j] = std::complex<float>((float) _prn[i],
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0.0);
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for (unsigned int j = (_period / 2); j < _period; j++)
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_dest[i * _period + j] = std::complex<float>((float) (-_prn[i]),
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0.0);
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}
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}
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void
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galileo_e1_sinboc_61_gen(std::complex<float>* _dest, int* _prn,
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unsigned int _length_out)
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{
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const unsigned int _length_in = Galileo_E1_B_CODE_LENGTH_CHIPS;
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unsigned int _period = (unsigned int) (_length_out / _length_in);
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for (unsigned int i = 0; i < _length_in; i++)
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{
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for (unsigned int j = 0; j < _period; j += 2)
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_dest[i * _period + j] = std::complex<float>((float) _prn[i],
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0.0);
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for (unsigned int j = 1; j < _period; j += 2)
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_dest[i * _period + j] = std::complex<float>((float) (-_prn[i]),
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0.0);
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}
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}
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void
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galileo_e1_gen(std::complex<float>* _dest, int* _prn, char _Signal[3])
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{
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std::string _galileo_signal = _Signal;
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const unsigned int _codeLength = 12 * Galileo_E1_B_CODE_LENGTH_CHIPS;
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const float alpha = sqrt(10.0 / 11.0);
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const float beta = sqrt(1.0 / 11.0);
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std::complex<float> sinboc_11[49152]; // 12*4096 (_codeLength not accepted by Clang )
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std::complex<float> sinboc_61[49152];
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galileo_e1_sinboc_11_gen(sinboc_11, _prn, _codeLength); //generate sinboc(1,1) 12 samples per chip
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galileo_e1_sinboc_61_gen(sinboc_61, _prn, _codeLength); //generate sinboc(6,1) 12 samples per chip
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if (_galileo_signal.rfind("1B") != std::string::npos && _galileo_signal.length() >= 2)
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{
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for (unsigned int i = 0; i < _codeLength; i++)
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{
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_dest[i] = alpha * sinboc_11[i] + beta * sinboc_61[i];
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}
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}
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else if (_galileo_signal.rfind("1C") != std::string::npos && _galileo_signal.length() >= 2)
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{
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for (unsigned int i = 0; i < _codeLength; i++)
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{
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_dest[i] = alpha * sinboc_11[i] - beta * sinboc_61[i];
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}
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}
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else
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return;
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}
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void
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galileo_e1_code_gen_complex_sampled(std::complex<float>* _dest, char _Signal[3],
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bool _cboc, unsigned int _prn, signed int _fs, unsigned int _chip_shift)
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{
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// This function is based on the GNU software GPS for MATLAB in the Kay Borre book
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unsigned int _samplesPerCode;
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const unsigned int _codeFreqBasis = Galileo_E1_CODE_CHIP_RATE_HZ; //Hz
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unsigned int _codeLength = Galileo_E1_B_CODE_LENGTH_CHIPS;
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int primary_code_E1_chips[4096];
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_samplesPerCode = round(_fs / (_codeFreqBasis / _codeLength));
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galileo_e1_code_gen_int(primary_code_E1_chips, _Signal, _prn, 0); //generate Galileo E1 code, 1 sample per chip
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if (_cboc == true)
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{
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_codeLength = 12 * Galileo_E1_B_CODE_LENGTH_CHIPS;
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if (_fs != 12 * _codeFreqBasis)
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{
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std::complex<float> _signal_E1[4096];
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galileo_e1_gen(_signal_E1, primary_code_E1_chips, _Signal); //generate cboc 12 samples per chip
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resampler(_signal_E1, _dest, 12 * _codeFreqBasis, _fs,
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_codeLength, _samplesPerCode); //resamples code to fs
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}
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else
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{
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galileo_e1_gen(_dest, primary_code_E1_chips, _Signal); //generate cboc 12 samples per chip
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}
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}
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else
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{
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//--- Find number of samples per spreading code ----------------------------
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_codeLength = 2 * Galileo_E1_B_CODE_LENGTH_CHIPS;
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if (_fs != 2 * _codeFreqBasis)
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{
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std::complex<float> _signal_E1[8192];
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galileo_e1_sinboc_11_gen(_signal_E1, primary_code_E1_chips,
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_codeLength); //generate sinboc(1,1) 2 samples per chip
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resampler(_signal_E1, _dest, 2 * _codeFreqBasis, _fs,
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_codeLength, _samplesPerCode); //resamples code to fs
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}
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else
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{
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galileo_e1_sinboc_11_gen(_dest, primary_code_E1_chips,
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_codeLength); //generate sinboc(1,1) 2 samples per chip }
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}
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}
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}
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