mirror of https://github.com/gnss-sdr/gnss-sdr
320 lines
11 KiB
C++
320 lines
11 KiB
C++
/*!
|
|
* \file gps_l1_ca_pcps_acquisition_cc.h
|
|
* \brief Brief description of the file here
|
|
* \author Javier Arribas, 2011. jarribas(at)cttc.es
|
|
* Luis Esteve, 2011. luis(at)epsilon-formacion.com
|
|
*
|
|
* Detailed description of the file here if needed.
|
|
*
|
|
* -------------------------------------------------------------------------
|
|
*
|
|
* Copyright (C) 2010-2011 (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 "gps_l1_ca_pcps_acquisition_cc.h"
|
|
#include "gps_sdr_signal_processing.h"
|
|
#include "control_message_factory.h"
|
|
#include "gps_sdr_x86.h"
|
|
|
|
#include <gnuradio/gr_io_signature.h>
|
|
|
|
#include <sstream>
|
|
|
|
#include <glog/log_severity.h>
|
|
#include <glog/logging.h>
|
|
|
|
using google::LogMessage;
|
|
|
|
gps_l1_ca_pcps_acquisition_cc_sptr gps_l1_ca_pcps_make_acquisition_cc(
|
|
unsigned int sampled_ms, unsigned int doppler_max, long freq,
|
|
long fs_in, int samples_per_ms, gr_msg_queue_sptr queue, bool dump,
|
|
std::string dump_filename)
|
|
{
|
|
|
|
return gps_l1_ca_pcps_acquisition_cc_sptr(
|
|
new gps_l1_ca_pcps_acquisition_cc(sampled_ms, doppler_max, freq,
|
|
fs_in, samples_per_ms, queue, dump, dump_filename));
|
|
}
|
|
|
|
gps_l1_ca_pcps_acquisition_cc::gps_l1_ca_pcps_acquisition_cc(
|
|
unsigned int sampled_ms, unsigned int doppler_max, long freq,
|
|
long fs_in, int samples_per_ms, gr_msg_queue_sptr queue, bool dump,
|
|
std::string dump_filename) :
|
|
gr_block("gps_l1_ca_pcps_acquisition_cc", gr_make_io_signature(1, 1,
|
|
sizeof(gr_complex) * samples_per_ms), gr_make_io_signature(0, 0,
|
|
sizeof(gr_complex) * samples_per_ms))
|
|
{
|
|
|
|
// SAMPLE COUNTER
|
|
d_sample_counter = 0;
|
|
|
|
d_active = false;
|
|
d_dump = dump;
|
|
d_queue = queue;
|
|
d_dump_filename = dump_filename;
|
|
|
|
d_freq = freq;
|
|
d_fs_in = fs_in;
|
|
|
|
d_samples_per_ms = samples_per_ms;
|
|
d_sampled_ms = sampled_ms;
|
|
|
|
d_doppler_max = doppler_max;
|
|
|
|
d_satellite = 0;
|
|
|
|
d_fft_size = d_sampled_ms * d_samples_per_ms;
|
|
|
|
d_doppler_freq = 0.0;
|
|
d_code_phase = 0;
|
|
d_mag = 0;
|
|
d_input_power = 0.0;
|
|
|
|
d_sine_if = new gr_complex[d_fft_size];
|
|
|
|
d_fft_codes = (gr_complex*)malloc(sizeof(gr_complex) * d_samples_per_ms);
|
|
|
|
// Direct FFT
|
|
d_fft_if = new gri_fft_complex(d_fft_size, true);
|
|
|
|
// Inverse FFT
|
|
d_ifft = new gri_fft_complex(d_fft_size, false);
|
|
|
|
DLOG(INFO) << "fs in " << d_fs_in;
|
|
DLOG(INFO) << "samples per ms " << d_samples_per_ms;
|
|
DLOG(INFO) << "doppler max " << d_doppler_max;
|
|
DLOG(INFO) << "freq " << d_freq;
|
|
DLOG(INFO) << "satellite " << d_satellite;
|
|
DLOG(INFO) << "sampled_ms " << d_sampled_ms;
|
|
DLOG(INFO) << "fft_size " << d_fft_size;
|
|
DLOG(INFO) << "dump filename " << d_dump_filename;
|
|
DLOG(INFO) << "dump " << d_dump;
|
|
}
|
|
|
|
gps_l1_ca_pcps_acquisition_cc::~gps_l1_ca_pcps_acquisition_cc()
|
|
{
|
|
delete d_sine_if;
|
|
delete d_fft_codes;
|
|
|
|
if (d_dump)
|
|
{
|
|
d_dump_file.close();
|
|
}
|
|
}
|
|
|
|
void gps_l1_ca_pcps_acquisition_cc::set_satellite(unsigned int satellite)
|
|
{
|
|
d_satellite = satellite;
|
|
d_code_phase = 0;
|
|
d_doppler_freq = 0;
|
|
d_mag = 0;
|
|
d_input_power = 0.0;
|
|
|
|
// Now the GPS codes are generated on the fly using a custom version of the GPS code generator
|
|
code_gen_complex_sampled(d_fft_if->get_inbuf(), satellite, d_fs_in, 0);
|
|
d_fft_if->execute(); // We need the FFT of GPS C/A code
|
|
//Conjugate the local code
|
|
//TODO Optimize it !
|
|
for (unsigned int i = 0; i < d_fft_size; i++)
|
|
{
|
|
d_fft_codes[i] = std::complex<float>(
|
|
d_fft_if->get_outbuf()[i].real(),
|
|
-d_fft_if->get_outbuf()[i].imag());
|
|
d_fft_codes[i] = d_fft_codes[i] / (float)d_fft_size; //to correct the scale factor introduced by FFTW
|
|
}
|
|
//memcpy(d_fft_codes,d_fft_if->get_outbuf(),sizeof(gr_complex)*d_samples_per_ms);
|
|
|
|
// std::stringstream filename;
|
|
// std::streamsize n = 2*sizeof(float)*(d_fft_size); // complex file write
|
|
// filename.str("");
|
|
// filename << "./data/code.dat";
|
|
// std::cout<<filename.str().c_str();
|
|
// std::cout<<".\n";
|
|
// d_dump_file.open(filename.str().c_str(), std::ios::out | std::ios::binary);
|
|
//
|
|
//
|
|
// d_dump_file.write((char*)d_ifft->get_inbuf(), n); //write directly |abs(·)|^2 in this Doppler bin
|
|
// //d_dump_file.write((char*)d_sine_if, n); //to be read with read_complex_binary() -> test OK
|
|
// d_dump_file.close();
|
|
}
|
|
signed int gps_l1_ca_pcps_acquisition_cc::prn_code_phase()
|
|
{
|
|
return d_code_phase;
|
|
}
|
|
|
|
int gps_l1_ca_pcps_acquisition_cc::general_work(int noutput_items,
|
|
gr_vector_int &ninput_items, gr_vector_const_void_star &input_items,
|
|
gr_vector_void_star &output_items)
|
|
{
|
|
|
|
/*!
|
|
* By J.Arribas
|
|
* Acquisition A strategy (Kay Borre book + CFAR threshold):
|
|
* 1º- Compute the input signal power estimation
|
|
* 2º- Doppler serial search loop
|
|
* 3º- Perform the FFT-based circular convolution (parallel time search)
|
|
* 4º- record the maximum peak and the associated synchronization parameters
|
|
* 5º- Compute the test statistics and compare to the threshold
|
|
* 6º- Declare positive or negative acquisition using a message queue
|
|
*/
|
|
|
|
if (!d_active)
|
|
{
|
|
d_sample_counter += d_fft_size * noutput_items; // sample counter
|
|
consume_each(noutput_items);
|
|
}
|
|
else
|
|
{
|
|
d_sample_counter += d_fft_size; // sample counter
|
|
// initialize acquisition algorithm
|
|
|
|
int doppler;
|
|
unsigned int indext = 0;
|
|
float magt = 0.0;
|
|
const gr_complex *in = (const gr_complex *)input_items[0]; //Get the input samples pointer
|
|
bool positive_acquisition = false;
|
|
int acquisition_message = -1; //0=STOP_CHANNEL 1=ACQ_SUCCEES 2=ACQ_FAIL
|
|
|
|
//aux vars
|
|
unsigned int i;
|
|
std::stringstream filename;
|
|
std::streamsize n = 2 * sizeof(float) * (d_fft_size); // complex file write
|
|
|
|
LOG_AT_LEVEL(INFO) << "Channel: " << d_channel
|
|
<< " , doing acquisition of satellite: " << d_satellite
|
|
<< " ,sample stamp: " << d_sample_counter << ", threshold: "
|
|
<< d_threshold << ", doppler_max: " << d_doppler_max
|
|
<< ", doppler_step: " << d_doppler_step;
|
|
|
|
// 1º Compute the input signal power estimation
|
|
for (i = 0; i < d_fft_size; i++)
|
|
{
|
|
d_input_power += std::abs(in[i]) * std::abs(in[i]);
|
|
}
|
|
d_input_power = d_input_power / ((float)d_fft_size
|
|
* (float)d_fft_size);
|
|
|
|
// 2º- Doppler frequency search loop
|
|
for (doppler = (int)(-d_doppler_max); doppler < (int)d_doppler_max; doppler
|
|
+= d_doppler_step)
|
|
{ // doppler search steps
|
|
//Perform the carrier wipe-off
|
|
sine_gen_complex(d_sine_if, d_freq + doppler, d_fs_in, d_fft_size);
|
|
for (i = 0; i < d_fft_size; i++)
|
|
{
|
|
d_fft_if->get_inbuf()[i] = in[i] * d_sine_if[i];
|
|
}
|
|
|
|
//3º- Perform the FFT-based circular convolution (parallel time search)
|
|
d_fft_if->execute(); //TODO Optimize me
|
|
for (i = 0; i < d_fft_size; i++)
|
|
{
|
|
d_ifft->get_inbuf()[i] = (d_fft_if->get_outbuf()[i]
|
|
* d_fft_codes[i]) / (float)d_fft_size;
|
|
}
|
|
d_ifft->execute();
|
|
|
|
x86_gr_complex_mag(d_ifft->get_outbuf(), d_fft_size); // d_ifft->get_outbuf()=|abs(·)|^2 and the array is converted from CPX->Float
|
|
x86_float_max((float*)d_ifft->get_outbuf(), &indext, &magt,
|
|
d_fft_size); // find max of |abs(·)|^2 -> index and magt
|
|
|
|
magt = magt / (float)d_fft_size;
|
|
// Record results to files
|
|
if (d_dump)
|
|
{
|
|
filename.str("");
|
|
filename << "./data/fft_" << doppler << "_.dat";
|
|
std::cout << filename.str().c_str();
|
|
std::cout << ".\n";
|
|
d_dump_file.open(filename.str().c_str(), std::ios::out
|
|
| std::ios::binary);
|
|
d_dump_file.write((char*)d_ifft->get_outbuf(), n); //write directly |abs(·)|^2 in this Doppler bin
|
|
d_dump_file.close();
|
|
}
|
|
// 4º- record the maximum peak and the associated synchronization parameters
|
|
if (d_mag < magt)
|
|
{
|
|
d_mag = magt;
|
|
d_code_phase = indext;
|
|
d_doppler_freq = doppler;
|
|
}
|
|
}
|
|
|
|
// 5º- Compute the test statistics and compare to the threshold
|
|
d_test_statistics = d_mag / d_input_power;
|
|
// 6º- Declare positive or negative acquisition using a message queue
|
|
|
|
if (d_test_statistics > d_threshold)
|
|
{ //0.004
|
|
positive_acquisition = true;
|
|
d_acq_sample_stamp = d_sample_counter;
|
|
LOG_AT_LEVEL(INFO) << "positive acquisition";
|
|
LOG_AT_LEVEL(INFO) << "satellite " << d_satellite;
|
|
LOG_AT_LEVEL(INFO) << "sample_stamp" << d_sample_counter;
|
|
LOG_AT_LEVEL(INFO) << "test statistics value "
|
|
<< d_test_statistics;
|
|
LOG_AT_LEVEL(INFO) << "test statistics threshold " << d_threshold;
|
|
LOG_AT_LEVEL(INFO) << "code phase " << d_code_phase;
|
|
LOG_AT_LEVEL(INFO) << "doppler " << d_doppler_freq;
|
|
LOG_AT_LEVEL(INFO) << "magnitude " << d_mag;
|
|
LOG_AT_LEVEL(INFO) << "input signal power " << d_input_power;
|
|
|
|
}
|
|
else
|
|
{
|
|
LOG_AT_LEVEL(INFO) << "negative acquisition";
|
|
LOG_AT_LEVEL(INFO) << "satellite " << d_satellite;
|
|
LOG_AT_LEVEL(INFO) << "sample_stamp " << d_sample_counter;
|
|
LOG_AT_LEVEL(INFO) << "test statistics value "
|
|
<< d_test_statistics;
|
|
LOG_AT_LEVEL(INFO) << "test statistics threshold " << d_threshold;
|
|
LOG_AT_LEVEL(INFO) << "magnitude " << d_mag;
|
|
LOG_AT_LEVEL(INFO) << "input signal power " << d_input_power;
|
|
|
|
//restart acquisition variables
|
|
d_input_power = 0.0;
|
|
d_mag = 0.0;
|
|
|
|
}
|
|
d_active = false;
|
|
|
|
if (positive_acquisition)
|
|
{
|
|
acquisition_message = 1;
|
|
}
|
|
else
|
|
{
|
|
acquisition_message = 2;
|
|
}
|
|
|
|
d_channel_internal_queue->push(acquisition_message);
|
|
|
|
consume_each(1);
|
|
}
|
|
return 0;
|
|
}
|