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gnss-sdr/src/algorithms/libs/galileo_e5_signal_processing.cc
2014-06-01 13:22:26 +02:00

120 lines
4.8 KiB
C++

/*!
* \file galileo_e5_signal_processing.cc
* \brief This library implements various functions for Galileo E5 signals such
* as replica code generation
* \author Marc Sales, 2014. marcsales92(at)gmail.com
*
* Detailed description of the file here if needed.
*
* -------------------------------------------------------------------------
*
* Copyright (C) 2010-2014 (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/>.
*
* -------------------------------------------------------------------------
*/
#include "galileo_e5_signal_processing.h"
void galileo_e5_a_code_gen_complex(std::complex<float>* _dest, signed int _prn, char _Signal[3])
{
std::string _galileo_signal = _Signal;
unsigned int prn=_prn-1;
unsigned int index=0;
//int _code_int[(int)Galileo_E5a_CODE_LENGTH_CHIPS];
int a[4];
if ((_prn < 1) || (_prn > 50))
{
return;
}
if (_galileo_signal.rfind("5Q") != std::string::npos && _galileo_signal.length() >= 2)
{
for (size_t i = 0; i < Galileo_E5a_Q_PRIMARY_CODE[prn].length(); i++)
{
// hex_to_binary_converter(&_dest[index],
// Galileo_E5a_Q_PRIMARY_CODE[prn].at(i));
// hex_to_binary_converter(&_code_int[index],
// Galileo_E5a_Q_PRIMARY_CODE[prn].at(i));
hex_to_binary_converter(&a[0],
Galileo_E5a_Q_PRIMARY_CODE[prn].at(i));
_dest[index]=std::complex<float>(float(a[0]),0.0);
_dest[index+1]=std::complex<float>(float(a[1]),0.0);
_dest[index+2]=std::complex<float>(float(a[2]),0.0);
_dest[index+3]=std::complex<float>(float(a[3]),0.0);
index = index + 4;
}
}
else if (_galileo_signal.rfind("5I") != std::string::npos && _galileo_signal.length() >= 2)
{
for (size_t i = 0; i < Galileo_E5a_I_PRIMARY_CODE[prn].length(); i++)
{
// hex_to_binary_converter(&_code_int[index],
// Galileo_E5a_I_PRIMARY_CODE[prn].at(i));
hex_to_binary_converter(&a[0],
Galileo_E5a_I_PRIMARY_CODE[prn].at(i));
_dest[index]=std::complex<float>(float(a[0]),0.0);
_dest[index+1]=std::complex<float>(float(a[1]),0.0);
_dest[index+2]=std::complex<float>(float(a[2]),0.0);
_dest[index+3]=std::complex<float>(float(a[3]),0.0);
index = index + 4;
}
}
}
void galileo_e5_a_code_gen_complex_sampled(std::complex<float>* _dest, char _Signal[3],
unsigned int _prn, signed int _fs, unsigned int _chip_shift,
bool _secondary_flag)
{
// This function is based on the GNU software GPS for MATLAB in the Kay Borre book
std::complex<float> _code[Galileo_E5a_CODE_LENGTH_CHIPS];
std::string _galileo_signal = _Signal;
signed int _samplesPerCode, _codeValueIndex;
float _ts;
float _tc;
const int _codeFreqBasis = Galileo_E5a_CODE_CHIP_RATE_HZ; //Hz
unsigned int _codeLength = Galileo_E5a_CODE_LENGTH_CHIPS;
std::complex<float> primary_code_E5a_chips[(int)Galileo_E5a_CODE_LENGTH_CHIPS];
_samplesPerCode = round(_fs / (_codeFreqBasis / _codeLength));
const unsigned int delay = (((int)Galileo_E5a_CODE_LENGTH_CHIPS - _chip_shift)
% (int)Galileo_E5a_CODE_LENGTH_CHIPS)
* _samplesPerCode / Galileo_E5a_CODE_LENGTH_CHIPS;
galileo_e5_a_code_gen_complex(_code , _prn , _Signal);
if (_fs != _codeFreqBasis)
{
std::complex<float>* _resampled_signal = new std::complex<float>[_codeLength];
resampler(_code, _resampled_signal, _codeFreqBasis, _fs,
_codeLength, _samplesPerCode); //resamples code to fs
delete[] _code;
_code = _resampled_signal;
}
// TODO secundary code generated here??
for (unsigned int i = 0; i < _samplesPerCode; i++)
{
_dest[(i+delay)%_samplesPerCode] = _code[i];
}
delete[] _code;
}