mirrors
/
gnss-sdr
mirror of https://github.com/gnss-sdr/gnss-sdr
1
0
Fork 0
Code Issues Releases Wiki Activity
gnss-sdr/src/algorithms/signal_generator/gnuradio_blocks/signal_generator_c.cc

343 lines
14 KiB
C++
Raw Blame History

/*!
* \file signal_generator_c.cc
* \brief GNU Radio source block that generates synthesized GNSS signal.
* \author Marc Molina, 2013. marc.molina.pena@gmail.com
*
* -------------------------------------------------------------------------
*
* Copyright (C) 2010-2012 (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/>.
*
* -------------------------------------------------------------------------
*/
//#ifdef HAVE_CONFIG_H
//#include "config.h"
//#endif
#include "signal_generator_c.h"
#include <gnuradio/io_signature.h>
#include "gps_sdr_signal_processing.h"
#include "galileo_e1_signal_processing.h"
#include <volk/volk.h>
#include "nco_lib.h"
/*
* Create a new instance of signal_generator_c and return
* a boost shared_ptr. This is effectively the public constructor.
*/
signal_generator_c_sptr
signal_make_generator_c (std::vector<std::string> system, const std::vector<unsigned int> &PRN,
const std::vector<float> &CN0_dB, const std::vector<float> &doppler_Hz,
const std::vector<unsigned int> &delay_chips, bool data_flag, bool noise_flag,
unsigned int fs_in, unsigned int vector_length, float BW_BB)
{
return gnuradio::get_initial_sptr(new signal_generator_c(system, PRN, CN0_dB, doppler_Hz, delay_chips,
data_flag, noise_flag, fs_in, vector_length, BW_BB));
}
/*
* The private constructor
*/
signal_generator_c::signal_generator_c (std::vector<std::string> system, const std::vector<unsigned int> &PRN,
const std::vector<float> &CN0_dB, const std::vector<float> &doppler_Hz,
const std::vector<unsigned int> &delay_chips, bool data_flag, bool noise_flag,
unsigned int fs_in, unsigned int vector_length, float BW_BB) :
gr::block ("signal_gen_cc", gr::io_signature::make(0, 0, sizeof(gr_complex)),
gr::io_signature::make(1, 1, sizeof(gr_complex)*vector_length)),
system_(system),
PRN_(PRN),
CN0_dB_(CN0_dB),
doppler_Hz_(doppler_Hz),
delay_chips_(delay_chips),
data_flag_(data_flag),
noise_flag_(noise_flag),
fs_in_(fs_in),
num_sats_(PRN.size()),
vector_length_(vector_length),
BW_BB_(BW_BB*(float)fs_in/2.0)
{
init();
generate_codes();
}
void signal_generator_c::init()
{
if (posix_memalign((void**)&complex_phase_, 16, vector_length_ * sizeof(gr_complex)) == 0){};
// True if Gallileo satellites are present
bool gallileo_signal = std::find(system_.begin(), system_.end(), "E") != system_.end();
for (unsigned int sat = 0; sat < num_sats_; sat++)
{
start_phase_rad_.push_back(0);
current_data_bits_.push_back(gr_complex(1,0));
ms_counter_.push_back(0);
if (system_[sat] == "G")
{
samples_per_code_.push_back(round((float)fs_in_
/ (GPS_L1_CA_CODE_RATE_HZ / GPS_L1_CA_CODE_LENGTH_CHIPS)));
num_of_codes_per_vector_.push_back(gallileo_signal ? 4*(int)Galileo_E1_C_SECONDARY_CODE_LENGTH : 1);
data_bit_duration_ms_.push_back(1e3/GPS_CA_TELEMETRY_RATE_BITS_SECOND);
}
else if (system_[sat] == "E")
{
samples_per_code_.push_back(round((float)fs_in_ / (Galileo_E1_CODE_CHIP_RATE_HZ
/ Galileo_E1_B_CODE_LENGTH_CHIPS)));
num_of_codes_per_vector_.push_back((int)Galileo_E1_C_SECONDARY_CODE_LENGTH);
data_bit_duration_ms_.push_back(1e3/Galileo_E1_B_SYMBOL_RATE_BPS);
}
}
random_ = new gr::random();
// std::cout << "fs_in: " << fs_in_ << std::endl;
// std::cout << "data_flag: " << data_flag_ << std::endl;
// std::cout << "noise_flag_: " << noise_flag_ << std::endl;
// std::cout << "num_sats_: " << num_sats_ << std::endl;
// std::cout << "vector_length_: " << vector_length_ << std::endl;
// std::cout << "BW_BB_: " << BW_BB_ << std::endl;
// for (unsigned int i = 0; i < num_sats_; i++)
// {
// std::cout << "Sat " << i << ": " << std::endl;
// std::cout << " System " << system_[i] << ": " << std::endl;
// std::cout << " PRN: " << PRN_[i] << std::endl;
// std::cout << " CN0: " << CN0_dB_[i] << std::endl;
// std::cout << " Doppler: " << doppler_Hz_[i] << std::endl;
// std::cout << " Delay: " << delay_chips_[i] << std::endl;
// std::cout << " Samples per code = " << samples_per_code_[i] << std::endl;
// std::cout << " codes per vector = " << num_of_codes_per_vector_[i] << std::endl;
// std::cout << " data_bit_duration = " << data_bit_duration_ms_[i] << std::endl;
// }
}
void signal_generator_c::generate_codes()
{
sampled_code_data_.reset(new gr_complex*[num_sats_]);
sampled_code_pilot_.reset(new gr_complex*[num_sats_]);
for (unsigned int sat = 0; sat < num_sats_; sat++)
{
if (posix_memalign((void**)&(sampled_code_data_[sat]), 16,
vector_length_ * sizeof(gr_complex)) == 0){};
gr_complex code[samples_per_code_[sat]];
if (system_[sat] == "G")
{
// Generate one code-period of 1C signal
gps_l1_ca_code_gen_complex_sampled(code, PRN_[sat], fs_in_,
(int)GPS_L1_CA_CODE_LENGTH_CHIPS-delay_chips_[sat]);
// Obtain the desired CN0 assuming that Pn = 1.
if (noise_flag_)
{
for (unsigned int i = 0; i < samples_per_code_[sat]; i++)
{
code[i] *= sqrt(pow(10,CN0_dB_[sat]/10)/BW_BB_);
}
}
// Concatenate "num_of_codes_per_vector_" codes
for (unsigned int i = 0; i < num_of_codes_per_vector_[sat]; i++)
{
memcpy(&(sampled_code_data_[sat][i*samples_per_code_[sat]]),
code, sizeof(gr_complex)*samples_per_code_[sat]);
}
}
else if (system_[sat] == "E")
{
// Generate one code-period of E1B signal
bool cboc = true;
char signal[3];
strcpy(signal, "1B");
galileo_e1_code_gen_complex_sampled(code, signal, cboc, PRN_[sat], fs_in_,
(int)Galileo_E1_B_CODE_LENGTH_CHIPS-delay_chips_[sat]);
// Obtain the desired CN0 assuming that Pn = 1.
if (noise_flag_)
{
for (unsigned int i = 0; i < samples_per_code_[sat]; i++)
{
code[i] *= sqrt(pow(10,CN0_dB_[sat]/10)/BW_BB_/2);
}
}
// Concatenate "num_of_codes_per_vector_" codes
for (unsigned int i = 0; i < num_of_codes_per_vector_[sat]; i++)
{
memcpy(&(sampled_code_data_[sat][i*samples_per_code_[sat]]),
code, sizeof(gr_complex)*samples_per_code_[sat]);
}
// Generate E1C signal (25 code-periods, with secondary code)
if (posix_memalign((void**)&(sampled_code_pilot_[sat]), 16,
vector_length_ * sizeof(gr_complex)) == 0){};
strcpy(signal, "1C");
galileo_e1_code_gen_complex_sampled(sampled_code_pilot_[sat], signal, cboc, PRN_[sat], fs_in_,
(int)Galileo_E1_B_CODE_LENGTH_CHIPS-delay_chips_[sat], true);
// Obtain the desired CN0 assuming that Pn = 1.
if (noise_flag_)
{
for (unsigned int i = 0; i < vector_length_; i++)
{
sampled_code_pilot_[sat][i] *= sqrt(pow(10,CN0_dB_[sat]/10)/BW_BB_/2);
}
}
}
}
}
/*
* Our virtual destructor.
*/
signal_generator_c::~signal_generator_c()
{
for (unsigned int sat = 0; sat < num_sats_; sat++)
{
free(sampled_code_data_[sat]);
if (system_[sat] == "E")
{
free(sampled_code_pilot_[sat]);
}
}
delete random_;
}
int
signal_generator_c::general_work (int noutput_items,
gr_vector_int &ninput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
gr_complex *out = (gr_complex *) output_items[0];
unsigned int out_idx = 0;
unsigned int i = 0;
unsigned int k = 0;
for (out_idx = 0; out_idx < vector_length_; out_idx++)
{
out[out_idx] = gr_complex(0.0,0.0);
}
for (unsigned int sat = 0; sat < num_sats_; sat++)
{
float phase_step_rad = -(float)GPS_TWO_PI*doppler_Hz_[sat] / (float)fs_in_;
fxp_nco(complex_phase_, vector_length_, start_phase_rad_[sat], phase_step_rad);
start_phase_rad_[sat] += vector_length_ * phase_step_rad;
out_idx = 0;
if (system_[sat] == "G")
{
unsigned int delay_samples = (delay_chips_[sat] % (int)GPS_L1_CA_CODE_LENGTH_CHIPS)
* samples_per_code_[sat] / GPS_L1_CA_CODE_LENGTH_CHIPS;
for (i = 0; i < num_of_codes_per_vector_[sat]; i++)
{
for (k = 0; k < delay_samples; k++)
{
out[out_idx] += sampled_code_data_[sat][out_idx]
* current_data_bits_[sat]
* complex_phase_[out_idx];
out_idx++;
}
if (ms_counter_[sat] == 0 && data_flag_)
{
// New random data bit
current_data_bits_[sat] = gr_complex((rand()%2) == 0 ? 1 : -1, 0);
}
for (k = delay_samples; k < samples_per_code_[sat]; k++)
{
out[out_idx] += sampled_code_data_[sat][out_idx]
* current_data_bits_[sat]
* complex_phase_[out_idx];
out_idx++;
}
ms_counter_[sat] = (ms_counter_[sat] + (int)round(1e3*GPS_L1_CA_CODE_PERIOD))
% data_bit_duration_ms_[sat];
}
}
else if (system_[sat] == "E")
{
unsigned int delay_samples = (delay_chips_[sat] % (int)Galileo_E1_B_CODE_LENGTH_CHIPS)
* samples_per_code_[sat] / Galileo_E1_B_CODE_LENGTH_CHIPS;
for (i = 0; i < num_of_codes_per_vector_[sat]; i++)
{
for (k = 0; k < delay_samples; k++)
{
out[out_idx] += (sampled_code_data_[sat][out_idx] * current_data_bits_[sat]
- sampled_code_pilot_[sat][out_idx])
* complex_phase_[out_idx];
out_idx++;
}
if (ms_counter_[sat] == 0 && data_flag_)
{
// New random data bit
current_data_bits_[sat] = gr_complex((rand()%2) == 0 ? 1 : -1, 0);
}
for (k = delay_samples; k < samples_per_code_[sat]; k++)
{
out[out_idx] += (sampled_code_data_[sat][out_idx] * current_data_bits_[sat]
- sampled_code_pilot_[sat][out_idx])
* complex_phase_[out_idx];
out_idx++;
}
ms_counter_[sat] = (ms_counter_[sat] + (int)round(1e3*Galileo_E1_CODE_PERIOD))
% data_bit_duration_ms_[sat];
}
}
}
if (noise_flag_)
{
for (out_idx = 0; out_idx < vector_length_; out_idx++)
{
out[out_idx] += gr_complex(random_->gasdev(),random_->gasdev());
}
}
// Tell runtime system how many output items we produced.
return 1;
}
Reference in New Issue View Git Blame Copy Permalink