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/acquisition/gnuradio_blocks/pcps_multithread_acquisitio...

433 lines
17 KiB
C++
Raw Blame History

/*!
* \file pcps_multithread_acquisition_cc.cc
* \brief This class implements a Parallel Code Phase Search Acquisition
* \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@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 "pcps_multithread_acquisition_cc.h"
#include <sstream>
#include <glog/logging.h>
#include <gnuradio/io_signature.h>
#include <volk/volk.h>
#include "gnss_signal_processing.h"
#include "control_message_factory.h"
using google::LogMessage;
pcps_multithread_acquisition_cc_sptr pcps_make_multithread_acquisition_cc(
unsigned int sampled_ms, unsigned int max_dwells,
unsigned int doppler_max, long freq, long fs_in,
int samples_per_ms, int samples_per_code,
bool bit_transition_flag,
gr::msg_queue::sptr queue, bool dump,
std::string dump_filename)
{
return pcps_multithread_acquisition_cc_sptr(
new pcps_multithread_acquisition_cc(sampled_ms, max_dwells, doppler_max, freq, fs_in, samples_per_ms,
samples_per_code, bit_transition_flag, queue, dump, dump_filename));
}
pcps_multithread_acquisition_cc::pcps_multithread_acquisition_cc(
unsigned int sampled_ms, unsigned int max_dwells,
unsigned int doppler_max, long freq, long fs_in,
int samples_per_ms, int samples_per_code,
bool bit_transition_flag,
gr::msg_queue::sptr queue, bool dump,
std::string dump_filename) :
gr::block("pcps_multithread_acquisition_cc",
gr::io_signature::make(1, 1, sizeof(gr_complex) * sampled_ms * samples_per_ms),
gr::io_signature::make(0, 0, sizeof(gr_complex) * sampled_ms * samples_per_ms))
{
d_sample_counter = 0; // SAMPLE COUNTER
d_active = false;
d_state = 0;
d_core_working = false;
d_queue = queue;
d_freq = freq;
d_fs_in = fs_in;
d_samples_per_ms = samples_per_ms;
d_samples_per_code = samples_per_code;
d_sampled_ms = sampled_ms;
d_max_dwells = max_dwells;
d_well_count = 0;
d_doppler_max = doppler_max;
d_fft_size = d_sampled_ms * d_samples_per_ms;
d_mag = 0;
d_input_power = 0.0;
d_num_doppler_bins = 0;
d_bit_transition_flag = bit_transition_flag;
d_in_dwell_count = 0;
d_in_buffer = new gr_complex*[d_max_dwells];
//todo: do something if posix_memalign fails
for (unsigned int i = 0; i < d_max_dwells; i++)
{
d_in_buffer[i] = static_cast<gr_complex*>(volk_malloc(d_fft_size * sizeof(gr_complex), volk_get_alignment()));
}
d_fft_codes = static_cast<gr_complex*>(volk_malloc(d_fft_size * sizeof(gr_complex), volk_get_alignment()));
d_magnitude = static_cast<float*>(volk_malloc(d_fft_size * sizeof(float), volk_get_alignment()));
// Direct FFT
d_fft_if = new gr::fft::fft_complex(d_fft_size, true);
// Inverse FFT
d_ifft = new gr::fft::fft_complex(d_fft_size, false);
// For dumping samples into a file
d_dump = dump;
d_dump_filename = dump_filename;
}
pcps_multithread_acquisition_cc::~pcps_multithread_acquisition_cc()
{
if (d_num_doppler_bins > 0)
{
for (unsigned int i = 0; i < d_num_doppler_bins; i++)
{
volk_free(d_grid_doppler_wipeoffs[i]);
}
delete[] d_grid_doppler_wipeoffs;
}
for (unsigned int i = 0; i < d_max_dwells; i++)
{
volk_free(d_in_buffer[i]);
}
delete[] d_in_buffer;
volk_free(d_fft_codes);
volk_free(d_magnitude);
delete d_ifft;
delete d_fft_if;
if (d_dump)
{
d_dump_file.close();
}
}
void pcps_multithread_acquisition_cc::init()
{
d_gnss_synchro->Acq_delay_samples = 0.0;
d_gnss_synchro->Acq_doppler_hz = 0.0;
d_gnss_synchro->Acq_samplestamp_samples = 0;
d_mag = 0.0;
d_input_power = 0.0;
// Count the number of bins
d_num_doppler_bins = 0;
for (int doppler = (int)(-d_doppler_max);
doppler <= (int)d_doppler_max;
doppler += d_doppler_step)
{
d_num_doppler_bins++;
}
// Create the carrier Doppler wipeoff signals
d_grid_doppler_wipeoffs = new gr_complex*[d_num_doppler_bins];
for (unsigned int doppler_index=0;doppler_index<d_num_doppler_bins;doppler_index++)
{
d_grid_doppler_wipeoffs[doppler_index] = static_cast<gr_complex*>(volk_malloc(d_fft_size * sizeof(gr_complex), volk_get_alignment()));
int doppler = -(int)d_doppler_max + d_doppler_step * doppler_index;
complex_exp_gen_conj(d_grid_doppler_wipeoffs[doppler_index],
d_freq + doppler, d_fs_in, d_fft_size);
}
}
void pcps_multithread_acquisition_cc::set_local_code(std::complex<float> * code)
{
memcpy(d_fft_if->get_inbuf(), code, sizeof(gr_complex)*d_fft_size);
d_fft_if->execute(); // We need the FFT of local code
//Conjugate the local code
volk_32fc_conjugate_32fc(d_fft_codes, d_fft_if->get_outbuf(), d_fft_size);
}
void pcps_multithread_acquisition_cc::acquisition_core()
{
// initialize acquisition algorithm
int doppler;
unsigned int indext = 0;
float magt = 0.0;
float fft_normalization_factor = (float)d_fft_size * (float)d_fft_size;
gr_complex* in = d_in_buffer[d_well_count];
unsigned long int samplestamp = d_sample_counter_buffer[d_well_count];
d_input_power = 0.0;
d_mag = 0.0;
d_well_count++;
DLOG(INFO) << "Channel: " << d_channel
<< " , doing acquisition of satellite: " << d_gnss_synchro->System << " "<< d_gnss_synchro->PRN
<< " ,sample stamp: " << d_sample_counter << ", threshold: "
<< d_threshold << ", doppler_max: " << d_doppler_max
<< ", doppler_step: " << d_doppler_step;
// 1- Compute the input signal power estimation
volk_32fc_magnitude_squared_32f(d_magnitude, in, d_fft_size);
volk_32f_accumulator_s32f(&d_input_power, d_magnitude, d_fft_size);
d_input_power /= (float)d_fft_size;
// 2- Doppler frequency search loop
for (unsigned int doppler_index = 0; doppler_index < d_num_doppler_bins; doppler_index++)
{
// doppler search steps
doppler = -(int)d_doppler_max + d_doppler_step*doppler_index;
volk_32fc_x2_multiply_32fc(d_fft_if->get_inbuf(), in,
d_grid_doppler_wipeoffs[doppler_index], d_fft_size);
// 3- Perform the FFT-based convolution (parallel time search)
// Compute the FFT of the carrier wiped--off incoming signal
d_fft_if->execute();
// Multiply carrier wiped--off, Fourier transformed incoming signal
// with the local FFT'd code reference using SIMD operations with VOLK library
volk_32fc_x2_multiply_32fc(d_ifft->get_inbuf(),
d_fft_if->get_outbuf(), d_fft_codes, d_fft_size);
// compute the inverse FFT
d_ifft->execute();
// Search maximum
volk_32fc_magnitude_squared_32f(d_magnitude, d_ifft->get_outbuf(), d_fft_size);
volk_32f_index_max_16u(&indext, d_magnitude, d_fft_size);
// Normalize the maximum value to correct the scale factor introduced by FFTW
magt = d_magnitude[indext] / (fft_normalization_factor * fft_normalization_factor);
// 4- record the maximum peak and the associated synchronization parameters
if (d_mag < magt)
{
d_mag = magt;
// In case that d_bit_transition_flag = true, we compare the potentially
// new maximum test statistics (d_mag/d_input_power) with the value in
// d_test_statistics. When the second dwell is being processed, the value
// of d_mag/d_input_power could be lower than d_test_statistics (i.e,
// the maximum test statistics in the previous dwell is greater than
// current d_mag/d_input_power). Note that d_test_statistics is not
// restarted between consecutive dwells in multidwell operation.
if (d_test_statistics < (d_mag / d_input_power) || !d_bit_transition_flag)
{
d_gnss_synchro->Acq_delay_samples = (double)(indext % d_samples_per_code);
d_gnss_synchro->Acq_doppler_hz = (double)doppler;
d_gnss_synchro->Acq_samplestamp_samples = samplestamp;
// 5- Compute the test statistics and compare to the threshold
//d_test_statistics = 2 * d_fft_size * d_mag / d_input_power;
d_test_statistics = d_mag / d_input_power;
}
}
// Record results to file if required
if (d_dump)
{
std::stringstream filename;
std::streamsize n = 2 * sizeof(float) * (d_fft_size); // complex file write
filename.str("");
filename << "../data/test_statistics_" << d_gnss_synchro->System
<<"_" << d_gnss_synchro->Signal << "_sat_"
<< d_gnss_synchro->PRN << "_doppler_" << doppler << ".dat";
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(x)|^2 in this Doppler bin?
d_dump_file.close();
}
}
if (!d_bit_transition_flag)
{
if (d_test_statistics > d_threshold)
{
d_state = 2; // Positive acquisition
}
else if (d_well_count == d_max_dwells)
{
d_state = 3; // Negative acquisition
}
}
else
{
if (d_well_count == d_max_dwells) // d_max_dwells = 2
{
if (d_test_statistics > d_threshold)
{
d_state = 2; // Positive acquisition
}
else
{
d_state = 3; // Negative acquisition
}
}
}
d_core_working = false;
}
int pcps_multithread_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)
{
int acquisition_message = -1; //0=STOP_CHANNEL 1=ACQ_SUCCEES 2=ACQ_FAIL
switch (d_state)
{
case 0:
{
if (d_active)
{
//restart acquisition variables
d_gnss_synchro->Acq_delay_samples = 0.0;
d_gnss_synchro->Acq_doppler_hz = 0.0;
d_gnss_synchro->Acq_samplestamp_samples = 0;
d_well_count = 0;
d_mag = 0.0;
d_input_power = 0.0;
d_test_statistics = 0.0;
d_in_dwell_count = 0;
d_sample_counter_buffer.clear();
d_state = 1;
}
d_sample_counter += d_fft_size * ninput_items[0]; // sample counter
break;
}
case 1:
{
if (d_in_dwell_count < d_max_dwells)
{
// Fill internal buffer with d_max_dwells signal blocks. This step ensures that
// consecutive signal blocks will be processed in multi-dwell operation. This is
// essential when d_bit_transition_flag = true.
unsigned int num_dwells = std::min((int)(d_max_dwells-d_in_dwell_count),ninput_items[0]);
for (unsigned int i = 0; i < num_dwells; i++)
{
memcpy(d_in_buffer[d_in_dwell_count++], (gr_complex*)input_items[i],
sizeof(gr_complex)*d_fft_size);
d_sample_counter += d_fft_size;
d_sample_counter_buffer.push_back(d_sample_counter);
}
if (ninput_items[0] > (int)num_dwells)
{
d_sample_counter += d_fft_size * (ninput_items[0]-num_dwells);
}
}
else
{
// We already have d_max_dwells consecutive blocks in the internal buffer,
// just skip input blocks.
d_sample_counter += d_fft_size * ninput_items[0];
}
// We create a new thread to process next block if the following
// conditions are fulfilled:
// 1. There are new blocks in d_in_buffer that have not been processed yet
// (d_well_count < d_in_dwell_count).
// 2. No other acquisition_core thead is working (!d_core_working).
// 3. d_state==1. We need to check again d_state because it can be modified at any
// moment by the external thread (may have changed since checked in the switch()).
// If the external thread has already declared positive (d_state=2) or negative
// (d_state=3) acquisition, we don't have to process next block!!
if ((d_well_count < d_in_dwell_count) && !d_core_working && d_state==1)
{
d_core_working = true;
boost::thread(&pcps_multithread_acquisition_cc::acquisition_core, this);
}
break;
}
case 2:
{
// Declare positive acquisition using a message queue
DLOG(INFO) << "positive acquisition";
DLOG(INFO) << "satellite " << d_gnss_synchro->System << " " << d_gnss_synchro->PRN;
DLOG(INFO) << "sample_stamp " << d_sample_counter;
DLOG(INFO) << "test statistics value " << d_test_statistics;
DLOG(INFO) << "test statistics threshold " << d_threshold;
DLOG(INFO) << "code phase " << d_gnss_synchro->Acq_delay_samples;
DLOG(INFO) << "doppler " << d_gnss_synchro->Acq_doppler_hz;
DLOG(INFO) << "magnitude " << d_mag;
DLOG(INFO) << "input signal power " << d_input_power;
d_active = false;
d_state = 0;
d_sample_counter += d_fft_size * ninput_items[0]; // sample counter
acquisition_message = 1;
d_channel_internal_queue->push(acquisition_message);
break;
}
case 3:
{
// Declare negative acquisition using a message queue
DLOG(INFO) << "negative acquisition";
DLOG(INFO) << "satellite " << d_gnss_synchro->System << " " << d_gnss_synchro->PRN;
DLOG(INFO) << "sample_stamp " << d_sample_counter;
DLOG(INFO) << "test statistics value " << d_test_statistics;
DLOG(INFO) << "test statistics threshold " << d_threshold;
DLOG(INFO) << "code phase " << d_gnss_synchro->Acq_delay_samples;
DLOG(INFO) << "doppler " << d_gnss_synchro->Acq_doppler_hz;
DLOG(INFO) << "magnitude " << d_mag;
DLOG(INFO) << "input signal power " << d_input_power;
d_active = false;
d_state = 0;
d_sample_counter += d_fft_size * ninput_items[0]; // sample counter
acquisition_message = 2;
d_channel_internal_queue->push(acquisition_message);
break;
}
}
consume_each(ninput_items[0]);
return 0;
}
Reference in New Issue View Git Blame Copy Permalink