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/*!
* \file gps_l1_ca_pcps_acquisition.cc
* \brief Adapts a PCPS acquisition block to an AcquisitionInterface for
* GPS L1 C/A signals
* \authors <ul>
* <li> Javier Arribas, 2011. jarribas(at)cttc.es
* <li> Luis Esteve, 2012. luis(at)epsilon-formacion.com
* <li> Marc Molina, 2013. marc.molina.pena(at)gmail.com
* </ul>
*
* -------------------------------------------------------------------------
*
* Copyright (C) 2010-2015 (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 "gps_l1_ca_pcps_acquisition.h"
#include <boost/math/distributions/exponential.hpp>
#include <glog/logging.h>
#include "gps_sdr_signal_processing.h"
#include "GPS_L1_CA.h"
#include "configuration_interface.h"
using google::LogMessage;
GpsL1CaPcpsAcquisition::GpsL1CaPcpsAcquisition(
ConfigurationInterface* configuration, std::string role,
unsigned int in_streams, unsigned int out_streams) :
role_(role), in_streams_(in_streams), out_streams_(out_streams)
{
configuration_ = configuration;
std::string default_item_type = "gr_complex";
std::string default_dump_filename = "./data/acquisition.dat";
DLOG(INFO) << "role " << role;
item_type_ = configuration_->property(role + ".item_type", default_item_type);
fs_in_ = configuration_->property("GNSS-SDR.internal_fs_hz", 2048000);
if_ = configuration_->property(role + ".if", 0);
dump_ = configuration_->property(role + ".dump", false);
doppler_max_ = configuration_->property(role + ".doppler_max", 5000);
sampled_ms_ = configuration_->property(role + ".coherent_integration_time_ms", 1);
bit_transition_flag_ = configuration_->property(role + ".bit_transition_flag", false);
use_CFAR_algorithm_flag_=configuration_->property(role + ".use_CFAR_algorithm", true); //will be false in future versions
max_dwells_ = configuration_->property(role + ".max_dwells", 1);
dump_filename_ = configuration_->property(role + ".dump_filename", default_dump_filename);
//--- Find number of samples per spreading code -------------------------
code_length_ = round(fs_in_ / (GPS_L1_CA_CODE_RATE_HZ / GPS_L1_CA_CODE_LENGTH_CHIPS));
vector_length_ = code_length_ * sampled_ms_;
if( bit_transition_flag_ )
{
vector_length_ *= 2;
}
code_ = new gr_complex[vector_length_];
if (item_type_.compare("cshort") == 0 )
{
item_size_ = sizeof(lv_16sc_t);
acquisition_sc_ = pcps_make_acquisition_sc(sampled_ms_, max_dwells_,
doppler_max_, if_, fs_in_, code_length_, code_length_,
bit_transition_flag_, use_CFAR_algorithm_flag_, dump_, dump_filename_);
DLOG(INFO) << "acquisition(" << acquisition_sc_->unique_id() << ")";
}else{
item_size_ = sizeof(gr_complex);
acquisition_cc_ = pcps_make_acquisition_cc(sampled_ms_, max_dwells_,
doppler_max_, if_, fs_in_, code_length_, code_length_,
bit_transition_flag_, use_CFAR_algorithm_flag_, dump_, dump_filename_);
DLOG(INFO) << "acquisition(" << acquisition_cc_->unique_id() << ")";
}
stream_to_vector_ = gr::blocks::stream_to_vector::make(item_size_, vector_length_);
DLOG(INFO) << "stream_to_vector(" << stream_to_vector_->unique_id() << ")";
if (item_type_.compare("cbyte") == 0)
{
cbyte_to_float_x2_ = make_complex_byte_to_float_x2();
float_to_complex_ = gr::blocks::float_to_complex::make();
}
channel_ = 0;
threshold_ = 0.0;
doppler_step_ = 0;
gnss_synchro_ = 0;
}
GpsL1CaPcpsAcquisition::~GpsL1CaPcpsAcquisition()
{
delete[] code_;
}
void GpsL1CaPcpsAcquisition::set_channel(unsigned int channel)
{
channel_ = channel;
if (item_type_.compare("cshort") == 0)
{
acquisition_sc_->set_channel(channel_);
}
else
{
acquisition_cc_->set_channel(channel_);
}
}
void GpsL1CaPcpsAcquisition::set_threshold(float threshold)
{
float pfa = configuration_->property(role_ + ".pfa", 0.0);
if(pfa == 0.0)
{
threshold_ = threshold;
}
else
{
threshold_ = calculate_threshold(pfa);
}
DLOG(INFO) << "Channel " << channel_ << " Threshold = " << threshold_;
if (item_type_.compare("cshort") == 0)
{
acquisition_sc_->set_threshold(threshold_);
}
else
{
acquisition_cc_->set_threshold(threshold_);
}
}
void GpsL1CaPcpsAcquisition::set_doppler_max(unsigned int doppler_max)
{
doppler_max_ = doppler_max;
if (item_type_.compare("cshort") == 0)
{
acquisition_sc_->set_doppler_max(doppler_max_);
}
else
{
acquisition_cc_->set_doppler_max(doppler_max_);
}
}
void GpsL1CaPcpsAcquisition::set_doppler_step(unsigned int doppler_step)
{
doppler_step_ = doppler_step;
if (item_type_.compare("cshort") == 0)
{
acquisition_sc_->set_doppler_step(doppler_step_);
}
else
{
acquisition_cc_->set_doppler_step(doppler_step_);
}
}
void GpsL1CaPcpsAcquisition::set_gnss_synchro(Gnss_Synchro* gnss_synchro)
{
gnss_synchro_ = gnss_synchro;
if (item_type_.compare("cshort") == 0)
{
acquisition_sc_->set_gnss_synchro(gnss_synchro_);
}
else
{
acquisition_cc_->set_gnss_synchro(gnss_synchro_);
}
}
signed int GpsL1CaPcpsAcquisition::mag()
{
if (item_type_.compare("cshort") == 0)
{
return acquisition_sc_->mag();
}
else
{
return acquisition_cc_->mag();
}
}
void GpsL1CaPcpsAcquisition::init()
{
if (item_type_.compare("cshort") == 0)
{
acquisition_sc_->init();
}
else
{
acquisition_cc_->init();
}
set_local_code();
}
void GpsL1CaPcpsAcquisition::set_local_code()
{
std::complex<float>* code = new std::complex<float>[code_length_];
gps_l1_ca_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_, 0);
for (unsigned int i = 0; i < sampled_ms_; i++)
{
memcpy(&(code_[i*code_length_]), code,
sizeof(gr_complex)*code_length_);
}
if (item_type_.compare("cshort") == 0)
{
acquisition_sc_->set_local_code(code_);
}
else
{
acquisition_cc_->set_local_code(code_);
}
delete[] code;
}
void GpsL1CaPcpsAcquisition::reset()
{
if (item_type_.compare("cshort") == 0)
{
acquisition_sc_->set_active(true);
}
else
{
acquisition_cc_->set_active(true);
}
}
void GpsL1CaPcpsAcquisition::set_state(int state)
{
if (item_type_.compare("cshort") == 0)
{
acquisition_sc_->set_state(state);
}
else
{
acquisition_cc_->set_state(state);
}
}
float GpsL1CaPcpsAcquisition::calculate_threshold(float pfa)
{
//Calculate the threshold
unsigned int frequency_bins = 0;
for (int doppler = (int)(-doppler_max_); doppler <= (int)doppler_max_; doppler += doppler_step_)
{
frequency_bins++;
}
DLOG(INFO) << "Channel " << channel_ << " Pfa = " << pfa;
unsigned int ncells = vector_length_ * frequency_bins;
double exponent = 1 / static_cast<double>(ncells);
double val = pow(1.0 - pfa, exponent);
double lambda = double(vector_length_);
boost::math::exponential_distribution<double> mydist (lambda);
float threshold = (float)quantile(mydist,val);
return threshold;
}
void GpsL1CaPcpsAcquisition::connect(gr::top_block_sptr top_block)
{
if (item_type_.compare("gr_complex") == 0)
{
top_block->connect(stream_to_vector_, 0, acquisition_cc_, 0);
}
else if (item_type_.compare("cshort") == 0)
{
top_block->connect(stream_to_vector_, 0, acquisition_sc_, 0);
}
else if (item_type_.compare("cbyte") == 0)
{
top_block->connect(cbyte_to_float_x2_, 0, float_to_complex_, 0);
top_block->connect(cbyte_to_float_x2_, 1, float_to_complex_, 1);
top_block->connect(float_to_complex_, 0, stream_to_vector_, 0);
top_block->connect(stream_to_vector_, 0, acquisition_cc_, 0);
}
else
{
LOG(WARNING) << item_type_ << " unknown acquisition item type";
}
}
void GpsL1CaPcpsAcquisition::disconnect(gr::top_block_sptr top_block)
{
if (item_type_.compare("gr_complex") == 0)
{
top_block->disconnect(stream_to_vector_, 0, acquisition_cc_, 0);
}
else if (item_type_.compare("cshort") == 0)
{
top_block->disconnect(stream_to_vector_, 0, acquisition_sc_, 0);
}
else if (item_type_.compare("cbyte") == 0)
{
// Since a byte-based acq implementation is not available,
// we just convert cshorts to gr_complex
top_block->disconnect(cbyte_to_float_x2_, 0, float_to_complex_, 0);
top_block->disconnect(cbyte_to_float_x2_, 1, float_to_complex_, 1);
top_block->disconnect(float_to_complex_, 0, stream_to_vector_, 0);
top_block->disconnect(stream_to_vector_, 0, acquisition_cc_, 0);
}
else
{
LOG(WARNING) << item_type_ << " unknown acquisition item type";
}
}
gr::basic_block_sptr GpsL1CaPcpsAcquisition::get_left_block()
{
if (item_type_.compare("gr_complex") == 0)
{
return stream_to_vector_;
}
else if (item_type_.compare("cshort") == 0)
{
return stream_to_vector_;
}
else if (item_type_.compare("cbyte") == 0)
{
return cbyte_to_float_x2_;
}
else
{
LOG(WARNING) << item_type_ << " unknown acquisition item type";
return nullptr;
}
}
gr::basic_block_sptr GpsL1CaPcpsAcquisition::get_right_block()
{
if (item_type_.compare("cshort") == 0)
{
return acquisition_sc_;
}
else
{
return acquisition_cc_;
}
}