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/*!
* \file pcps_acquisition_fine_doppler_acquisition_cc.cc
* \brief This class implements a Parallel Code Phase Search Acquisition with multi-dwells and fine Doppler estimation
* \authors <ul>
* <li> Javier Arribas, 2013. jarribas(at)cttc.es
* </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_acquisition_fine_doppler_cc.h"
#include <algorithm> // std::rotate
#include <sstream>
#include <glog/logging.h>
#include <gnuradio/io_signature.h>
#include <volk/volk.h>
#include "nco_lib.h"
#include "concurrent_map.h"
#include "gnss_signal_processing.h"
#include "gps_sdr_signal_processing.h"
#include "control_message_factory.h"
using google::LogMessage;
pcps_acquisition_fine_doppler_cc_sptr pcps_make_acquisition_fine_doppler_cc(
int max_dwells, unsigned int sampled_ms, int doppler_max, int doppler_min, long freq,
long fs_in, int samples_per_ms, boost::shared_ptr<gr::msg_queue> queue, bool dump,
std::string dump_filename)
{
return pcps_acquisition_fine_doppler_cc_sptr(
new pcps_acquisition_fine_doppler_cc(max_dwells, sampled_ms, doppler_max, doppler_min, freq,
fs_in, samples_per_ms, queue, dump, dump_filename));
}
pcps_acquisition_fine_doppler_cc::pcps_acquisition_fine_doppler_cc(
int max_dwells, unsigned int sampled_ms, int doppler_max, int doppler_min, long freq,
long fs_in, int samples_per_ms, boost::shared_ptr<gr::msg_queue> queue, bool dump,
std::string dump_filename) :
gr::block("pcps_acquisition_fine_doppler_cc",
gr::io_signature::make(1, 1, sizeof(gr_complex)),
gr::io_signature::make(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_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;
d_input_power = 0.0;
d_state = 0;
d_carrier = 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;
}
void pcps_acquisition_fine_doppler_cc::set_doppler_step(unsigned int doppler_step)
{
d_doppler_step = doppler_step;
// Create the search grid array
d_num_doppler_points = floor(std::abs(d_config_doppler_max - d_config_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] = static_cast<float*>(volk_malloc(d_fft_size * sizeof(float), volk_get_alignment()));
}
update_carrier_wipeoff();
}
void pcps_acquisition_fine_doppler_cc::free_grid_memory()
{
for (int i = 0; i < d_num_doppler_points; i++)
{
volk_free(d_grid_data[i]);
delete[] d_grid_doppler_wipeoffs[i];
}
delete d_grid_data;
delete d_grid_doppler_wipeoffs;
}
pcps_acquisition_fine_doppler_cc::~pcps_acquisition_fine_doppler_cc()
{
volk_free(d_carrier);
volk_free(d_fft_codes);
volk_free(d_magnitude);
delete d_ifft;
delete d_fft_if;
if (d_dump)
{
d_dump_file.close();
}
free_grid_memory();
}
void pcps_acquisition_fine_doppler_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_acquisition_fine_doppler_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_input_power = 0.0;
d_state = 0;
}
void pcps_acquisition_fine_doppler_cc::forecast (int noutput_items,
gr_vector_int &ninput_items_required)
{
ninput_items_required[0] = d_gnuradio_forecast_samples ; //set the required available samples in each call
}
void pcps_acquisition_fine_doppler_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_acquisition_fine_doppler_cc::update_carrier_wipeoff()
{
// 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_config_doppler_min + d_doppler_step*doppler_index;
// doppler search steps
// compute the carrier doppler wipe-off signal and store it
phase_step_rad = static_cast<float>(GPS_TWO_PI) * doppler_hz / static_cast<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_acquisition_fine_doppler_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(&tmp_intex_t, d_grid_data[i], d_fft_size);
if (d_grid_data[i][tmp_intex_t] > magt)
{
magt = d_grid_data[i][tmp_intex_t];
//std::cout<<magt<<std::endl;
index_doppler = i;
index_time = tmp_intex_t;
}
}
// Normalize the maximum value to correct the scale factor introduced by FFTW
fft_normalization_factor = static_cast<float>(d_fft_size) * static_cast<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 = magt/(d_input_power*std::sqrt(d_well_count));
// 4- record the maximum peak and the associated synchronization parameters
d_gnss_synchro->Acq_delay_samples = static_cast<double>(index_time);
d_gnss_synchro->Acq_doppler_hz = static_cast<double>(index_doppler * d_doppler_step + d_config_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_acquisition_fine_doppler_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
// Compute the input signal power estimation
float power = 0;
volk_32fc_magnitude_squared_32f(d_magnitude, in, d_fft_size);
volk_32f_accumulator_s32f(&power, d_magnitude, d_fft_size);
power /= static_cast<float>(d_fft_size);
return power;
}
int pcps_acquisition_fine_doppler_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_config_doppler_max
<< ", doppler_step: " << d_doppler_step;
// 2- Doppler frequency search loop
float* p_tmp_vector = static_cast<float*>(volk_malloc(d_fft_size * sizeof(float), volk_get_alignment()));
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(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();
// save the grid matrix delay file
volk_32fc_magnitude_squared_32f(p_tmp_vector, d_ifft->get_outbuf(), d_fft_size);
const float* old_vector = d_grid_data[doppler_index];
volk_32f_x2_add_32f(d_grid_data[doppler_index], old_vector, p_tmp_vector, d_fft_size);
}
volk_free(p_tmp_vector);
return d_fft_size;
}
int pcps_acquisition_fine_doppler_cc::estimate_Doppler(gr_vector_const_void_star &input_items, int available_samples)
{
// Direct FFT
int zero_padding_factor = 16;
int fft_size_extended = d_fft_size * zero_padding_factor;
gr::fft::fft_complex *fft_operator = new gr::fft::fft_complex(fft_size_extended, true);
//zero padding the entire vector
memset(fft_operator->get_inbuf(), 0, fft_size_extended * sizeof(gr_complex));
//1. generate local code aligned with the acquisition code phase estimation
gr_complex *code_replica = static_cast<gr_complex*>(volk_malloc(d_fft_size * sizeof(gr_complex), volk_get_alignment()));
gps_l1_ca_code_gen_complex_sampled(code_replica, d_gnss_synchro->PRN, d_fs_in, 0);
int shift_index = static_cast<int>(d_gnss_synchro->Acq_delay_samples);
// Rotate to align the local code replica using acquisition time delay estimation
if (shift_index != 0)
{
std::rotate(code_replica, code_replica + (d_fft_size - shift_index), code_replica + d_fft_size - 1);
}
//2. Perform code wipe-off
const gr_complex *in = (const gr_complex *)input_items[0]; //Get the input samples pointer
volk_32fc_x2_multiply_32fc(fft_operator->get_inbuf(), in, code_replica, d_fft_size);
// 3. Perform the FFT (zero padded!)
fft_operator->execute();
// 4. Compute the magnitude and find the maximum
float* p_tmp_vector = static_cast<float*>(volk_malloc(fft_size_extended * sizeof(float), volk_get_alignment()));
volk_32fc_magnitude_squared_32f(p_tmp_vector, fft_operator->get_outbuf(), fft_size_extended);
unsigned int tmp_index_freq = 0;
volk_32f_index_max_16u(&tmp_index_freq, p_tmp_vector, fft_size_extended);
//case even
int counter = 0;
float fftFreqBins[fft_size_extended];
for (int k=0; k < (fft_size_extended / 2); k++)
{
fftFreqBins[counter] = ((static_cast<float>(d_fs_in) / 2.0) * static_cast<float>(k)) / (static_cast<float>(fft_size_extended) / 2.0);
counter++;
}
for (int k = fft_size_extended / 2; k > 0; k--)
{
fftFreqBins[counter] = ((-static_cast<float>(d_fs_in) / 2) * static_cast<float>(k)) / (static_cast<float>(fft_size_extended) / 2.0);
counter++;
}
// 5. Update the Doppler estimation in Hz
if (abs(fftFreqBins[tmp_index_freq] - d_gnss_synchro->Acq_doppler_hz) < 1000)
{
d_gnss_synchro->Acq_doppler_hz = static_cast<double>(fftFreqBins[tmp_index_freq]);
//std::cout<<"FFT maximum present at "<<fftFreqBins[tmp_index_freq]<<" [Hz]"<<std::endl;
}
else
{
DLOG(INFO) << "Abs(Grid Doppler - FFT Doppler)=" << abs(fftFreqBins[tmp_index_freq] - d_gnss_synchro->Acq_doppler_hz);
DLOG(INFO) << "Error estimating fine frequency Doppler";
//debug log
//
// std::cout<<"FFT maximum present at "<<fftFreqBins[tmp_index_freq]<<" [Hz]"<<std::endl;
// std::stringstream filename;
// std::streamsize n = sizeof(gr_complex) * (d_fft_size);
//
// filename.str("");
// filename << "../data/code_prn_" << d_gnss_synchro->PRN << ".dat";
// d_dump_file.open(filename.str().c_str(), std::ios::out
// | std::ios::binary);
// d_dump_file.write((char*)code_replica, n); //write directly |abs(x)|^2 in this Doppler bin?
// d_dump_file.close();
//
// filename.str("");
// filename << "../data/signal_prn_" << d_gnss_synchro->PRN << ".dat";
// d_dump_file.open(filename.str().c_str(), std::ios::out
// | std::ios::binary);
// d_dump_file.write((char*)in, n); //write directly |abs(x)|^2 in this Doppler bin?
// d_dump_file.close();
//
//
// n = sizeof(float) * (fft_size_extended);
// filename.str("");
// filename << "../data/fft_prn_" << d_gnss_synchro->PRN << ".dat";
// d_dump_file.open(filename.str().c_str(), std::ios::out
// | std::ios::binary);
// d_dump_file.write((char*)p_tmp_vector, n); //write directly |abs(x)|^2 in this Doppler bin?
// d_dump_file.close();
}
// free memory!!
delete fft_operator;
volk_free(code_replica);
volk_free(p_tmp_vector);
return d_fft_size;
}
int pcps_acquisition_fine_doppler_cc::general_work(int noutput_items,
gr_vector_int &ninput_items, gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
/*!
* TODO: High sensitivity acquisition algorithm:
* State Mechine:
* S0. StandBy. If d_active==1 -> S1
* S1. 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 -> S5.
* S4. Positive_Acq: Send message and stop acq -> S0
* S5. Negative_Acq: Send message and stop acq -> S0
*/
switch (d_state)
{
case 0: // S0. StandBy
//DLOG(INFO) <<"S0"<<std::endl;
if (d_active == true)
{
reset_grid();
d_state = 1;
}
break;
case 1: // S1. ComputeGrid
//DLOG(INFO) <<"S1"<<std::endl;
compute_and_accumulate_grid(input_items);
d_well_count++;
if (d_well_count >= d_max_dwells)
{
d_state = 2;
}
break;
case 2: // Compute test statistics and decide
//DLOG(INFO) <<"S2"<<std::endl;
d_input_power = estimate_input_power(input_items);
d_test_statistics = search_maximum();
if (d_test_statistics > d_threshold)
{
d_state = 3; //perform fine doppler estimation
}
else
{
d_state = 5; //negative acquisition
}
break;
case 3: // Fine doppler estimation
//DLOG(INFO) <<"S3"<<std::endl;
DLOG(INFO) << "Performing fine Doppler estimation";
estimate_Doppler(input_items, ninput_items[0]); //disabled in repo
d_state = 4;
break;
case 4: // Positive_Acq
//DLOG(INFO) <<"S4"<<std::endl;
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;
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
d_state = 0;
break;
case 5: // Negative_Acq
//DLOG(INFO) <<"S5"<<std::endl;
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;
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
d_state = 0;
break;
default:
d_state = 0;
break;
}
//DLOG(INFO)<<"d_sample_counter="<<d_sample_counter<<std::endl;
d_sample_counter += d_fft_size; // sample counter
consume_each(d_fft_size);
return 0;
}
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