|
|
|
@@ -1,9 +1,8 @@
|
|
|
|
|
/*!
|
|
|
|
|
* \file pcps_acquisition_cc.cc
|
|
|
|
|
* \brief This class implements a Parallel Code Phase Search Acquisition
|
|
|
|
|
* \file pcps_assisted_acquisition_cc.cc
|
|
|
|
|
* \brief This class implements a Parallel Code Phase Search Acquisition with assistance and multi-dwells
|
|
|
|
|
* \authors <ul>
|
|
|
|
|
* <li> Javier Arribas, 2011. jarribas(at)cttc.es
|
|
|
|
|
* <li> Luis Esteve, 2012. luis(at)epsilon-formacion.com
|
|
|
|
|
* <li> Javier Arribas, 2013. jarribas(at)cttc.es
|
|
|
|
|
* </ul>
|
|
|
|
|
*
|
|
|
|
|
* -------------------------------------------------------------------------
|
|
|
|
@@ -34,77 +33,95 @@
|
|
|
|
|
#include "pcps_assisted_acquisition_cc.h"
|
|
|
|
|
#include "gnss_signal_processing.h"
|
|
|
|
|
#include "control_message_factory.h"
|
|
|
|
|
#include "gps_acq_assist.h"
|
|
|
|
|
#include <gnuradio/gr_io_signature.h>
|
|
|
|
|
#include <sstream>
|
|
|
|
|
#include <glog/log_severity.h>
|
|
|
|
|
#include <glog/logging.h>
|
|
|
|
|
#include <volk/volk.h>
|
|
|
|
|
#include "nco_lib.h"
|
|
|
|
|
#include "concurrent_map.h"
|
|
|
|
|
|
|
|
|
|
extern concurrent_map<Gps_Acq_Assist> global_gps_acq_assist_map;
|
|
|
|
|
|
|
|
|
|
using google::LogMessage;
|
|
|
|
|
|
|
|
|
|
pcps_assisted_acquisition_cc_sptr pcps_make_assisted_acquisition_cc(
|
|
|
|
|
int max_dwells, 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)
|
|
|
|
|
int max_dwells, unsigned int sampled_ms, int doppler_max, int doppler_min, long freq,
|
|
|
|
|
long fs_in, int samples_per_ms, gr_msg_queue_sptr queue, bool dump,
|
|
|
|
|
std::string dump_filename)
|
|
|
|
|
{
|
|
|
|
|
|
|
|
|
|
return pcps_assisted_acquisition_cc_sptr(
|
|
|
|
|
new pcps_assisted_acquisition_cc(max_dwells, sampled_ms, doppler_max, freq,
|
|
|
|
|
fs_in, samples_per_ms, queue, dump, dump_filename));
|
|
|
|
|
return pcps_assisted_acquisition_cc_sptr(
|
|
|
|
|
new pcps_assisted_acquisition_cc(max_dwells, sampled_ms, doppler_max, doppler_min, freq,
|
|
|
|
|
fs_in, samples_per_ms, queue, dump, dump_filename));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
pcps_assisted_acquisition_cc::pcps_assisted_acquisition_cc(
|
|
|
|
|
int max_dwells, 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("pcps_assisted_acquisition_cc",
|
|
|
|
|
gr_make_io_signature(1, 1, sizeof(gr_complex)),
|
|
|
|
|
gr_make_io_signature(0, 0, sizeof(gr_complex)))
|
|
|
|
|
int max_dwells, unsigned int sampled_ms, int doppler_max, int doppler_min, long freq,
|
|
|
|
|
long fs_in, int samples_per_ms, gr_msg_queue_sptr queue, bool dump,
|
|
|
|
|
std::string dump_filename) :
|
|
|
|
|
gr_block("pcps_assisted_acquisition_cc",
|
|
|
|
|
gr_make_io_signature(1, 1, sizeof(gr_complex)),
|
|
|
|
|
gr_make_io_signature(0, 0, sizeof(gr_complex)))
|
|
|
|
|
{
|
|
|
|
|
d_sample_counter = 0; // SAMPLE COUNTER
|
|
|
|
|
d_active = false;
|
|
|
|
|
d_queue = queue;
|
|
|
|
|
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_fft_size = d_sampled_ms * d_samples_per_ms;
|
|
|
|
|
// HS Acquisition
|
|
|
|
|
d_max_dwells= max_dwells;
|
|
|
|
|
d_gnuradio_forecast_samples=d_fft_size*d_max_dwells;
|
|
|
|
|
d_mag = 0;
|
|
|
|
|
d_input_power = 0.0;
|
|
|
|
|
d_sample_counter = 0; // SAMPLE COUNTER
|
|
|
|
|
d_active = false;
|
|
|
|
|
d_queue = queue;
|
|
|
|
|
d_freq = freq;
|
|
|
|
|
d_fs_in = fs_in;
|
|
|
|
|
d_samples_per_ms = samples_per_ms;
|
|
|
|
|
d_sampled_ms = sampled_ms;
|
|
|
|
|
d_config_doppler_max = doppler_max;
|
|
|
|
|
d_config_doppler_min=doppler_min;
|
|
|
|
|
d_fft_size = d_sampled_ms * d_samples_per_ms;
|
|
|
|
|
// HS Acquisition
|
|
|
|
|
d_max_dwells= max_dwells;
|
|
|
|
|
d_gnuradio_forecast_samples=d_fft_size*4;
|
|
|
|
|
d_input_power = 0.0;
|
|
|
|
|
d_state=0;
|
|
|
|
|
d_disable_assist=false;
|
|
|
|
|
//todo: do something if posix_memalign fails
|
|
|
|
|
if (posix_memalign((void**)&d_carrier, 16, d_fft_size * sizeof(gr_complex)) == 0){};
|
|
|
|
|
if (posix_memalign((void**)&d_fft_codes, 16, d_fft_size * sizeof(gr_complex)) == 0){};
|
|
|
|
|
|
|
|
|
|
//todo: do something if posix_memalign fails
|
|
|
|
|
if (posix_memalign((void**)&d_carrier, 16, d_fft_size * sizeof(gr_complex)) == 0){};
|
|
|
|
|
if (posix_memalign((void**)&d_fft_codes, 16, d_fft_size * sizeof(gr_complex)) == 0){};
|
|
|
|
|
// Direct FFT
|
|
|
|
|
d_fft_if = new gr::fft::fft_complex(d_fft_size, true);
|
|
|
|
|
|
|
|
|
|
// 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);
|
|
|
|
|
|
|
|
|
|
// 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;
|
|
|
|
|
// For dumping samples into a file
|
|
|
|
|
d_dump = dump;
|
|
|
|
|
d_dump_filename = dump_filename;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
void pcps_assisted_acquisition_cc::set_doppler_step(unsigned int doppler_step)
|
|
|
|
|
{
|
|
|
|
|
d_doppler_step = doppler_step;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
void pcps_assisted_acquisition_cc::free_grid_memory()
|
|
|
|
|
{
|
|
|
|
|
for (int i=0;i<d_num_doppler_points;i++)
|
|
|
|
|
{
|
|
|
|
|
delete[] d_grid_data[i];
|
|
|
|
|
delete[] d_grid_doppler_wipeoffs[i];
|
|
|
|
|
}
|
|
|
|
|
delete d_grid_data;
|
|
|
|
|
}
|
|
|
|
|
pcps_assisted_acquisition_cc::~pcps_assisted_acquisition_cc()
|
|
|
|
|
{
|
|
|
|
|
free(d_carrier);
|
|
|
|
|
free(d_fft_codes);
|
|
|
|
|
delete d_ifft;
|
|
|
|
|
delete d_fft_if;
|
|
|
|
|
if (d_dump)
|
|
|
|
|
{
|
|
|
|
|
d_dump_file.close();
|
|
|
|
|
}
|
|
|
|
|
free(d_carrier);
|
|
|
|
|
free(d_fft_codes);
|
|
|
|
|
delete d_ifft;
|
|
|
|
|
delete d_fft_if;
|
|
|
|
|
if (d_dump)
|
|
|
|
|
{
|
|
|
|
|
d_dump_file.close();
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
@@ -118,194 +135,315 @@ void pcps_assisted_acquisition_cc::set_local_code(std::complex<float> * code)
|
|
|
|
|
|
|
|
|
|
void pcps_assisted_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;
|
|
|
|
|
d_gnss_synchro->Acq_delay_samples = 0.0;
|
|
|
|
|
d_gnss_synchro->Acq_doppler_hz = 0.0;
|
|
|
|
|
d_gnss_synchro->Acq_samplestamp_samples = 0;
|
|
|
|
|
d_input_power = 0.0;
|
|
|
|
|
|
|
|
|
|
d_fft_if->execute(); // We need the FFT of local code
|
|
|
|
|
d_state=0;
|
|
|
|
|
|
|
|
|
|
d_fft_if->execute(); // We need the FFT of local code
|
|
|
|
|
|
|
|
|
|
//Conjugate the local code
|
|
|
|
|
volk_32fc_conjugate_32fc_a(d_fft_codes,d_fft_if->get_outbuf(),d_fft_size);
|
|
|
|
|
|
|
|
|
|
//Conjugate the local code
|
|
|
|
|
for (unsigned int i = 0; i < d_fft_size; i++)
|
|
|
|
|
{
|
|
|
|
|
d_fft_codes[i] = std::complex<float>(conj(d_fft_if->get_outbuf()[i]));
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
void pcps_assisted_acquisition_cc::forecast (int noutput_items,
|
|
|
|
|
gr_vector_int &ninput_items_required)
|
|
|
|
|
gr_vector_int &ninput_items_required)
|
|
|
|
|
{
|
|
|
|
|
ninput_items_required[0] = d_gnuradio_forecast_samples ; //set the required available samples in each call
|
|
|
|
|
ninput_items_required[0] = d_gnuradio_forecast_samples ; //set the required available samples in each call
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
void pcps_assisted_acquisition_cc::get_assistance()
|
|
|
|
|
{
|
|
|
|
|
Gps_Acq_Assist gps_acq_assisistance;
|
|
|
|
|
if (global_gps_acq_assist_map.read(this->d_gnss_synchro->PRN,gps_acq_assisistance)==true)
|
|
|
|
|
{
|
|
|
|
|
//TODO: use the LO tolerance here
|
|
|
|
|
if (gps_acq_assisistance.dopplerUncertainty>=1000)
|
|
|
|
|
{
|
|
|
|
|
d_doppler_max=gps_acq_assisistance.d_Doppler0+gps_acq_assisistance.dopplerUncertainty*2;
|
|
|
|
|
d_doppler_min=gps_acq_assisistance.d_Doppler0-gps_acq_assisistance.dopplerUncertainty*2;
|
|
|
|
|
}else{
|
|
|
|
|
d_doppler_max=gps_acq_assisistance.d_Doppler0+1000;
|
|
|
|
|
d_doppler_min=gps_acq_assisistance.d_Doppler0-1000;
|
|
|
|
|
}
|
|
|
|
|
this->d_disable_assist=false;
|
|
|
|
|
std::cout<<"Acq assist ENABLED for GPS SV "<<this->d_gnss_synchro->PRN<<" (Doppler max,Doppler min)=("
|
|
|
|
|
<<d_doppler_max<<","<<d_doppler_min<<")"<<std::endl;
|
|
|
|
|
}else{
|
|
|
|
|
this->d_disable_assist=true;
|
|
|
|
|
std::cout<<"Acq assist DISABLED for GPS SV "<<this->d_gnss_synchro->PRN<<std::endl;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
void pcps_assisted_acquisition_cc::reset_grid()
|
|
|
|
|
{
|
|
|
|
|
d_well_count=0;
|
|
|
|
|
for (int i=0;i<d_num_doppler_points;i++)
|
|
|
|
|
{
|
|
|
|
|
for (unsigned int j=0;j<d_fft_size;j++)
|
|
|
|
|
{
|
|
|
|
|
d_grid_data[i][j]=0.0;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
void pcps_assisted_acquisition_cc::redefine_grid()
|
|
|
|
|
{
|
|
|
|
|
if (this->d_disable_assist==true)
|
|
|
|
|
{
|
|
|
|
|
d_doppler_max=d_config_doppler_max;
|
|
|
|
|
d_doppler_min=d_config_doppler_min;
|
|
|
|
|
}
|
|
|
|
|
// Create the search grid array
|
|
|
|
|
d_num_doppler_points=floor(std::abs(d_doppler_max-d_doppler_min)/d_doppler_step);
|
|
|
|
|
|
|
|
|
|
d_grid_data=new float*[d_num_doppler_points];
|
|
|
|
|
for (int i=0;i<d_num_doppler_points;i++)
|
|
|
|
|
{
|
|
|
|
|
d_grid_data[i]=new float[d_fft_size];
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// create the carrier Doppler wipeoff signals
|
|
|
|
|
int doppler_hz;
|
|
|
|
|
float phase_step_rad;
|
|
|
|
|
d_grid_doppler_wipeoffs=new gr_complex*[d_num_doppler_points];
|
|
|
|
|
for (int doppler_index=0;doppler_index<d_num_doppler_points;doppler_index++)
|
|
|
|
|
{
|
|
|
|
|
|
|
|
|
|
doppler_hz=d_doppler_min+d_doppler_step*doppler_index;
|
|
|
|
|
// doppler search steps
|
|
|
|
|
// compute the carrier doppler wipe-off signal and store it
|
|
|
|
|
phase_step_rad = (float)GPS_TWO_PI*doppler_hz / (float)d_fs_in;
|
|
|
|
|
|
|
|
|
|
d_grid_doppler_wipeoffs[doppler_index]=new gr_complex[d_fft_size];
|
|
|
|
|
fxp_nco(d_grid_doppler_wipeoffs[doppler_index], d_fft_size,0, phase_step_rad);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
double pcps_assisted_acquisition_cc::search_maximum()
|
|
|
|
|
{
|
|
|
|
|
float magt = 0.0;
|
|
|
|
|
float fft_normalization_factor;
|
|
|
|
|
int index_doppler = 0;
|
|
|
|
|
unsigned int tmp_intex_t;
|
|
|
|
|
unsigned int index_time = 0;
|
|
|
|
|
|
|
|
|
|
for (int i=0;i<d_num_doppler_points;i++)
|
|
|
|
|
{
|
|
|
|
|
volk_32f_index_max_16u_a(&tmp_intex_t,d_grid_data[i],d_fft_size);
|
|
|
|
|
if (d_grid_data[i][tmp_intex_t] > magt)
|
|
|
|
|
{
|
|
|
|
|
magt = d_grid_data[i][index_time];
|
|
|
|
|
index_doppler = i;
|
|
|
|
|
index_time = tmp_intex_t;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Normalize the maximum value to correct the scale factor introduced by FFTW
|
|
|
|
|
fft_normalization_factor = (float)d_fft_size * (float)d_fft_size;
|
|
|
|
|
magt = magt / (fft_normalization_factor * fft_normalization_factor);
|
|
|
|
|
|
|
|
|
|
// 5- Compute the test statistics and compare to the threshold
|
|
|
|
|
d_test_statistics = 2 * d_fft_size * magt /(d_input_power*d_well_count);
|
|
|
|
|
|
|
|
|
|
// 4- record the maximum peak and the associated synchronization parameters
|
|
|
|
|
d_gnss_synchro->Acq_delay_samples = (double)index_time;
|
|
|
|
|
d_gnss_synchro->Acq_doppler_hz = (double)(index_doppler*d_doppler_step+d_doppler_min);
|
|
|
|
|
d_gnss_synchro->Acq_samplestamp_samples = d_sample_counter;
|
|
|
|
|
|
|
|
|
|
// 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_" << d_gnss_synchro->Acq_doppler_hz << ".dat";
|
|
|
|
|
d_dump_file.open(filename.str().c_str(), std::ios::out
|
|
|
|
|
| std::ios::binary);
|
|
|
|
|
d_dump_file.write((char*)d_grid_data[index_doppler], n); //write directly |abs(x)|^2 in this Doppler bin?
|
|
|
|
|
d_dump_file.close();
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return d_test_statistics;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
float pcps_assisted_acquisition_cc::estimate_input_power(gr_vector_const_void_star &input_items)
|
|
|
|
|
{
|
|
|
|
|
const gr_complex *in = (const gr_complex *)input_items[0]; //Get the input samples pointer
|
|
|
|
|
// 1- Compute the input signal power estimation
|
|
|
|
|
float* p_tmp_vector;
|
|
|
|
|
if (posix_memalign((void**)&p_tmp_vector, 16, d_fft_size * sizeof(float)) == 0){};
|
|
|
|
|
volk_32fc_magnitude_squared_32f_u(p_tmp_vector, in, d_fft_size);
|
|
|
|
|
|
|
|
|
|
const float* p_const_tmp_vector=p_tmp_vector;
|
|
|
|
|
float power;
|
|
|
|
|
volk_32f_accumulator_s32f_a(&power, p_const_tmp_vector, d_fft_size);
|
|
|
|
|
free(p_tmp_vector);
|
|
|
|
|
return ( power / (float)d_fft_size);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
int pcps_assisted_acquisition_cc::compute_and_accumulate_grid(gr_vector_const_void_star &input_items)
|
|
|
|
|
{
|
|
|
|
|
// initialize acquisition algorithm
|
|
|
|
|
const gr_complex *in = (const gr_complex *)input_items[0]; //Get the input samples pointer
|
|
|
|
|
|
|
|
|
|
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;
|
|
|
|
|
|
|
|
|
|
// 2- Doppler frequency search loop
|
|
|
|
|
float* p_tmp_vector;
|
|
|
|
|
if (posix_memalign((void**)&p_tmp_vector, 16, d_fft_size * sizeof(float)) == 0){};
|
|
|
|
|
|
|
|
|
|
for (int doppler_index=0;doppler_index<d_num_doppler_points;doppler_index++)
|
|
|
|
|
{
|
|
|
|
|
// doppler search steps
|
|
|
|
|
// Perform the carrier wipe-off
|
|
|
|
|
volk_32fc_x2_multiply_32fc_u(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_a(d_ifft->get_inbuf(), d_fft_if->get_outbuf(), d_fft_codes, d_fft_size);
|
|
|
|
|
|
|
|
|
|
// compute the inverse FFT
|
|
|
|
|
d_ifft->execute();
|
|
|
|
|
|
|
|
|
|
// save the grid matrix delay file
|
|
|
|
|
volk_32fc_magnitude_squared_32f_a(p_tmp_vector, d_ifft->get_outbuf(), d_fft_size);
|
|
|
|
|
const float* old_vector=d_grid_data[doppler_index];
|
|
|
|
|
volk_32f_x2_add_32f_a(d_grid_data[doppler_index],old_vector,p_tmp_vector,d_fft_size);
|
|
|
|
|
|
|
|
|
|
}
|
|
|
|
|
free(p_tmp_vector);
|
|
|
|
|
return d_fft_size;
|
|
|
|
|
}
|
|
|
|
|
int pcps_assisted_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)
|
|
|
|
|
gr_vector_int &ninput_items, gr_vector_const_void_star &input_items,
|
|
|
|
|
gr_vector_void_star &output_items)
|
|
|
|
|
{
|
|
|
|
|
/*
|
|
|
|
|
* By J.Arribas and L.Esteve
|
|
|
|
|
* Acquisition strategy (Kay Borre book + CFAR threshold):
|
|
|
|
|
* 1. Compute the input signal power estimation
|
|
|
|
|
* 2. Doppler serial search loop
|
|
|
|
|
* 3. Perform the FFT-based circular convolution (parallel time search)
|
|
|
|
|
* 4. Record the maximum peak and the associated synchronization parameters
|
|
|
|
|
* 5. Compute the test statistics and compare to the threshold
|
|
|
|
|
* 6. Declare positive or negative acquisition using a message queue
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
/*!
|
|
|
|
|
* TODO: High sensitivity acquisition algorithm:
|
|
|
|
|
* 0. Define search grid with assistance information. Reset grid matrix
|
|
|
|
|
* 1. Perform the FFT acqusition doppler and delay grid
|
|
|
|
|
* 2. accumulate the search grid matrix (#doppler_bins x #fft_size)
|
|
|
|
|
* 3. compare maximum to threshold and decide positive or negative
|
|
|
|
|
* 4. positive: stop. negative: if dwell_count< max_dwells -> dwell_count++ and goto 1, else -> negative acquisition: stop.
|
|
|
|
|
* State Mechine:
|
|
|
|
|
* S0. StandBy. If d_active==1 -> S1
|
|
|
|
|
* S1. GetAssist. Define search grid with assistance information. Reset grid matrix -> S2
|
|
|
|
|
* S2. ComputeGrid. Perform the FFT acqusition doppler and delay grid.
|
|
|
|
|
* Accumulate the search grid matrix (#doppler_bins x #fft_size)
|
|
|
|
|
* Compare maximum to threshold and decide positive or negative
|
|
|
|
|
* If T>=gamma -> S4 else
|
|
|
|
|
* If d_well_count<max_dwells -> S2
|
|
|
|
|
* else if !disable_assist -> S3
|
|
|
|
|
* else -> S5.
|
|
|
|
|
* S3. RedefineGrid. Open the grid search to unasisted acquisition. Reset counters and grid. -> S2
|
|
|
|
|
* S4. Positive_Acq: Send message and stop acq -> S0
|
|
|
|
|
* S5. Negative_Acq: Send message and stop acq -> S0
|
|
|
|
|
*/
|
|
|
|
|
if (!d_active)
|
|
|
|
|
{
|
|
|
|
|
d_sample_counter += d_fft_size * noutput_items; // sample counter
|
|
|
|
|
consume_each(noutput_items);
|
|
|
|
|
}
|
|
|
|
|
else
|
|
|
|
|
{
|
|
|
|
|
// initialize acquisition algorithm
|
|
|
|
|
int doppler;
|
|
|
|
|
unsigned int indext = 0;
|
|
|
|
|
float magt = 0.0;
|
|
|
|
|
float tmp_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;
|
|
|
|
|
float fft_normalization_factor;
|
|
|
|
|
|
|
|
|
|
d_sample_counter += d_fft_size; // sample counter
|
|
|
|
|
switch (d_state)
|
|
|
|
|
{
|
|
|
|
|
case 0: // S0. StandBy
|
|
|
|
|
if (d_active==true) d_state=1;
|
|
|
|
|
d_sample_counter += ninput_items[0]; // sample counter
|
|
|
|
|
consume_each(ninput_items[0]);
|
|
|
|
|
break;
|
|
|
|
|
case 1: // S1. GetAssist
|
|
|
|
|
get_assistance();
|
|
|
|
|
redefine_grid();
|
|
|
|
|
reset_grid();
|
|
|
|
|
d_sample_counter += ninput_items[0]; // sample counter
|
|
|
|
|
consume_each(ninput_items[0]);
|
|
|
|
|
d_state=2;
|
|
|
|
|
break;
|
|
|
|
|
case 2: // S2. ComputeGrid
|
|
|
|
|
int consumed_samples;
|
|
|
|
|
consumed_samples=compute_and_accumulate_grid(input_items);
|
|
|
|
|
d_well_count++;
|
|
|
|
|
if (d_well_count>=d_max_dwells)
|
|
|
|
|
{
|
|
|
|
|
d_state=3;
|
|
|
|
|
}
|
|
|
|
|
d_sample_counter+=consumed_samples;
|
|
|
|
|
consume_each(consumed_samples);
|
|
|
|
|
break;
|
|
|
|
|
case 3: // Compute test statistics and decide
|
|
|
|
|
d_input_power=estimate_input_power(input_items);
|
|
|
|
|
d_test_statistics=search_maximum();
|
|
|
|
|
if (d_test_statistics > d_threshold)
|
|
|
|
|
{
|
|
|
|
|
d_state=5;
|
|
|
|
|
}else{
|
|
|
|
|
if (d_disable_assist==false)
|
|
|
|
|
{
|
|
|
|
|
d_disable_assist=true;
|
|
|
|
|
std::cout<<"Acq assist DISABLED for GPS SV "<<this->d_gnss_synchro->PRN<<std::endl;
|
|
|
|
|
d_state=4;
|
|
|
|
|
}else{
|
|
|
|
|
d_state=6;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
d_sample_counter += ninput_items[0]; // sample counter
|
|
|
|
|
consume_each(ninput_items[0]);
|
|
|
|
|
break;
|
|
|
|
|
case 4: // RedefineGrid
|
|
|
|
|
free_grid_memory();
|
|
|
|
|
redefine_grid();
|
|
|
|
|
reset_grid();
|
|
|
|
|
d_sample_counter += ninput_items[0]; // sample counter
|
|
|
|
|
consume_each(ninput_items[0]);
|
|
|
|
|
d_state=2;
|
|
|
|
|
break;
|
|
|
|
|
case 5: // Positive_Acq
|
|
|
|
|
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) << "input signal power " << d_input_power;
|
|
|
|
|
|
|
|
|
|
//restart acquisition variables
|
|
|
|
|
d_gnss_synchro->Acq_delay_samples = 0.0;
|
|
|
|
|
d_gnss_synchro->Acq_doppler_hz = 0.0;
|
|
|
|
|
d_mag = 0.0;
|
|
|
|
|
d_input_power = 0.0;
|
|
|
|
|
d_active = false;
|
|
|
|
|
// Send message to channel queue //0=STOP_CHANNEL 1=ACQ_SUCCEES 2=ACQ_FAIL
|
|
|
|
|
d_channel_internal_queue->push(1); // 1-> positive acquisition
|
|
|
|
|
free_grid_memory();
|
|
|
|
|
// consume samples to not block the GNU Radio flowgraph
|
|
|
|
|
d_sample_counter += ninput_items[0]; // sample counter
|
|
|
|
|
consume_each(ninput_items[0]);
|
|
|
|
|
d_state=0;
|
|
|
|
|
break;
|
|
|
|
|
case 6: // Negative_Acq
|
|
|
|
|
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) << "input signal power " << d_input_power;
|
|
|
|
|
|
|
|
|
|
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;
|
|
|
|
|
d_active = false;
|
|
|
|
|
// Send message to channel queue //0=STOP_CHANNEL 1=ACQ_SUCCEES 2=ACQ_FAIL
|
|
|
|
|
d_channel_internal_queue->push(2); // 2-> negative acquisition
|
|
|
|
|
free_grid_memory();
|
|
|
|
|
// consume samples to not block the GNU Radio flowgraph
|
|
|
|
|
d_sample_counter += ninput_items[0]; // sample counter
|
|
|
|
|
consume_each(ninput_items[0]);
|
|
|
|
|
d_state=0;
|
|
|
|
|
break;
|
|
|
|
|
default:
|
|
|
|
|
d_state=0;
|
|
|
|
|
break;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// 1- Compute the input signal power estimation
|
|
|
|
|
for (i = 0; i < d_fft_size; i++)
|
|
|
|
|
{
|
|
|
|
|
d_input_power += std::norm(in[i]);
|
|
|
|
|
}
|
|
|
|
|
d_input_power = d_input_power / (float)d_fft_size;
|
|
|
|
|
|
|
|
|
|
// 2- 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
|
|
|
|
|
complex_exp_gen_conj(d_carrier, d_freq + doppler, d_fs_in, d_fft_size);
|
|
|
|
|
|
|
|
|
|
volk_32fc_x2_multiply_32fc_u(d_fft_if->get_inbuf(), in, d_carrier, 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_a(d_ifft->get_inbuf(), d_fft_if->get_outbuf(), d_fft_codes, d_fft_size);
|
|
|
|
|
|
|
|
|
|
// compute the inverse FFT
|
|
|
|
|
d_ifft->execute();
|
|
|
|
|
|
|
|
|
|
// Search maximum
|
|
|
|
|
indext = 0;
|
|
|
|
|
magt = 0;
|
|
|
|
|
fft_normalization_factor = (float)d_fft_size * (float)d_fft_size;
|
|
|
|
|
for (i = 0; i < d_fft_size; i++)
|
|
|
|
|
{
|
|
|
|
|
tmp_magt = std::norm(d_ifft->get_outbuf()[i]);
|
|
|
|
|
if (tmp_magt > magt)
|
|
|
|
|
{
|
|
|
|
|
magt = tmp_magt;
|
|
|
|
|
indext = i;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
// Normalize the maximum value to correct the scale factor introduced by FFTW
|
|
|
|
|
magt = magt / (fft_normalization_factor * fft_normalization_factor);
|
|
|
|
|
|
|
|
|
|
// 4- record the maximum peak and the associated synchronization parameters
|
|
|
|
|
if (d_mag < magt)
|
|
|
|
|
{
|
|
|
|
|
d_mag = magt;
|
|
|
|
|
d_gnss_synchro->Acq_delay_samples = (double)indext;
|
|
|
|
|
d_gnss_synchro->Acq_doppler_hz = (double)doppler;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// 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();
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// 5- Compute the test statistics and compare to the threshold
|
|
|
|
|
d_test_statistics = 2 * d_fft_size * d_mag / d_input_power;
|
|
|
|
|
|
|
|
|
|
// 6- Declare positive or negative acquisition using a message queue
|
|
|
|
|
if (d_test_statistics > d_threshold)
|
|
|
|
|
{
|
|
|
|
|
positive_acquisition = true;
|
|
|
|
|
d_gnss_synchro->Acq_samplestamp_samples = d_sample_counter;
|
|
|
|
|
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;
|
|
|
|
|
}
|
|
|
|
|
else
|
|
|
|
|
{
|
|
|
|
|
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;
|
|
|
|
|
|
|
|
|
|
if (positive_acquisition)
|
|
|
|
|
{
|
|
|
|
|
acquisition_message = 1;
|
|
|
|
|
}
|
|
|
|
|
else
|
|
|
|
|
{
|
|
|
|
|
acquisition_message = 2;
|
|
|
|
|
}
|
|
|
|
|
d_channel_internal_queue->push(acquisition_message);
|
|
|
|
|
consume_each(1);
|
|
|
|
|
}
|
|
|
|
|
return 0;
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
Javier Arribas