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gnss-sdr/src/algorithms/acquisition/gnuradio_blocks/pcps_opencl_acquisition_cc.cc

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/*!
* \file pcps_opencl_acquisition_cc.cc
* \brief This class implements a Parallel Code Phase Search Acquisition
* using OpenCL to offload some functions to the GPU.
*
* Acquisition strategy (Kay Borre book + CFAR threshold).
* <ol>
* <li> Compute the input signal power estimation
* <li> Doppler serial search loop
* <li> Perform the FFT-based circular convolution (parallel time search)
* <li> Record the maximum peak and the associated synchronization parameters
* <li> Compute the test statistics and compare to the threshold
* <li> Declare positive or negative acquisition using a message port
* </ol>
*
* Kay Borre book: K.Borre, D.M.Akos, N.Bertelsen, P.Rinder, and S.H.Jensen,
* "A Software-Defined GPS and Galileo Receiver. A Single-Frequency
* Approach", Birkhauser, 2007. pp 81-84
*
* \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) 2010-2020 (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.
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
* -----------------------------------------------------------------------------
*/
#include "pcps_opencl_acquisition_cc.h"
#include "MATH_CONSTANTS.h" // TWO_PI
#include "gnss_sdr_make_unique.h"
#include "opencl/fft_base_kernels.h"
#include "opencl/fft_internal.h"
#include <glog/logging.h>
#include <gnuradio/io_signature.h>
#include <volk/volk.h>
#include <volk_gnsssdr/volk_gnsssdr.h>
#include <algorithm>
#include <array>
#include <exception>
#include <fstream>
#include <iostream>
#include <sstream>
#include <utility>
pcps_opencl_acquisition_cc_sptr pcps_make_opencl_acquisition_cc(
uint32_t sampled_ms, uint32_t max_dwells,
uint32_t doppler_max, int64_t fs_in,
int samples_per_ms, int samples_per_code,
bool bit_transition_flag,
bool dump,
const std::string &dump_filename,
bool enable_monitor_output)
{
return pcps_opencl_acquisition_cc_sptr(
new pcps_opencl_acquisition_cc(sampled_ms, max_dwells, doppler_max, fs_in, samples_per_ms,
samples_per_code, bit_transition_flag, dump, dump_filename, enable_monitor_output));
}
pcps_opencl_acquisition_cc::pcps_opencl_acquisition_cc(
uint32_t sampled_ms,
uint32_t max_dwells,
uint32_t doppler_max,
int64_t fs_in,
int samples_per_ms,
int samples_per_code,
bool bit_transition_flag,
bool dump,
const std::string &dump_filename,
bool enable_monitor_output) : gr::block("pcps_opencl_acquisition_cc",
gr::io_signature::make(1, 1, static_cast<int>(sizeof(gr_complex) * sampled_ms * samples_per_ms)),
gr::io_signature::make(0, 1, sizeof(Gnss_Synchro)))
{
this->message_port_register_out(pmt::mp("events"));
d_sample_counter = 0ULL; // SAMPLE COUNTER
d_active = false;
d_state = 0;
d_core_working = false;
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_fft_size_pow2 = pow(2, ceil(log2(2 * d_fft_size)));
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_cl_fft_batch_size = 1;
d_in_buffer = std::vector<std::vector<gr_complex>>(d_max_dwells, std::vector<gr_complex>(d_fft_size));
d_magnitude.reserve(d_fft_size);
d_fft_codes.reserve(d_fft_size_pow2);
d_zero_vector = std::vector<gr_complex>(d_fft_size_pow2 - d_fft_size, 0.0);
d_opencl = init_opencl_environment("math_kernel.cl");
if (d_opencl != 0)
{
// Direct FFT
d_fft_if = std::make_unique<gr::fft::fft_complex>(d_fft_size, true);
// Inverse FFT
d_ifft = std::make_unique<gr::fft::fft_complex>(d_fft_size, false);
}
// For dumping samples into a file
d_dump = dump;
d_dump_filename = dump_filename;
d_enable_monitor_output = enable_monitor_output;
}
pcps_opencl_acquisition_cc::~pcps_opencl_acquisition_cc()
{
if (d_opencl == 0)
{
delete d_cl_queue;
delete d_cl_buffer_in;
delete d_cl_buffer_1;
delete d_cl_buffer_2;
delete d_cl_buffer_magnitude;
delete d_cl_buffer_fft_codes;
if (d_num_doppler_bins > 0)
{
delete[] d_cl_buffer_grid_doppler_wipeoffs;
}
clFFT_DestroyPlan(d_cl_fft_plan);
}
try
{
if (d_dump)
{
d_dump_file.close();
}
}
catch (const std::ofstream::failure &e)
{
std::cerr << "Problem closing Acquisition dump file: " << d_dump_filename << '\n';
}
catch (const std::exception &e)
{
std::cerr << e.what() << '\n';
}
}
int pcps_opencl_acquisition_cc::init_opencl_environment(const std::string &kernel_filename)
{
// get all platforms (drivers)
std::vector<cl::Platform> all_platforms;
cl::Platform::get(&all_platforms);
if (all_platforms.empty())
{
std::cout << "No OpenCL platforms found. Check OpenCL installation!\n";
return 1;
}
d_cl_platform = all_platforms[0]; // get default platform
std::cout << "Using platform: " << d_cl_platform.getInfo<CL_PLATFORM_NAME>()
<< '\n';
// get default GPU device of the default platform
std::vector<cl::Device> gpu_devices;
d_cl_platform.getDevices(CL_DEVICE_TYPE_GPU, &gpu_devices);
if (gpu_devices.empty())
{
std::cout << "No GPU devices found. Check OpenCL installation!\n";
return 2;
}
d_cl_device = gpu_devices[0];
std::vector<cl::Device> device;
device.push_back(d_cl_device);
std::cout << "Using device: " << d_cl_device.getInfo<CL_DEVICE_NAME>() << '\n';
cl::Context context(device);
d_cl_context = context;
// build the program from the source in the file
std::ifstream kernel_file(kernel_filename, std::ifstream::in);
std::string kernel_code(std::istreambuf_iterator<char>(kernel_file),
(std::istreambuf_iterator<char>()));
kernel_file.close();
cl::Program::Sources sources;
sources.push_back({kernel_code.c_str(), kernel_code.length()});
cl::Program program(context, sources);
if (program.build(device) != CL_SUCCESS)
{
std::cout << " Error building: "
<< program.getBuildInfo<CL_PROGRAM_BUILD_LOG>(device[0])
<< '\n';
return 3;
}
d_cl_program = program;
// create buffers on the device
d_cl_buffer_in = new cl::Buffer(d_cl_context, CL_MEM_READ_WRITE, sizeof(gr_complex) * d_fft_size);
d_cl_buffer_fft_codes = new cl::Buffer(d_cl_context, CL_MEM_READ_WRITE, sizeof(gr_complex) * d_fft_size_pow2);
d_cl_buffer_1 = new cl::Buffer(d_cl_context, CL_MEM_READ_WRITE, sizeof(gr_complex) * d_fft_size_pow2);
d_cl_buffer_2 = new cl::Buffer(d_cl_context, CL_MEM_READ_WRITE, sizeof(gr_complex) * d_fft_size_pow2);
d_cl_buffer_magnitude = new cl::Buffer(d_cl_context, CL_MEM_READ_WRITE, sizeof(float) * d_fft_size);
// create queue to which we will push commands for the device.
d_cl_queue = new cl::CommandQueue(d_cl_context, d_cl_device);
// create FFT plan
cl_int err;
clFFT_Dim3 dim = {d_fft_size_pow2, 1, 1};
d_cl_fft_plan = clFFT_CreatePlan(d_cl_context(), dim, clFFT_1D,
clFFT_InterleavedComplexFormat, &err);
if (err != 0)
{
delete d_cl_queue;
delete d_cl_buffer_in;
delete d_cl_buffer_1;
delete d_cl_buffer_2;
delete d_cl_buffer_magnitude;
delete d_cl_buffer_fft_codes;
std::cout << "Error creating OpenCL FFT plan.\n";
return 4;
}
return 0;
}
void pcps_opencl_acquisition_cc::init()
{
d_gnss_synchro->Flag_valid_acquisition = false;
d_gnss_synchro->Flag_valid_symbol_output = false;
d_gnss_synchro->Flag_valid_pseudorange = false;
d_gnss_synchro->Flag_valid_word = false;
d_gnss_synchro->Acq_doppler_step = 0U;
d_gnss_synchro->Acq_delay_samples = 0.0;
d_gnss_synchro->Acq_doppler_hz = 0.0;
d_gnss_synchro->Acq_samplestamp_samples = 0ULL;
d_mag = 0.0;
d_input_power = 0.0;
// Count the number of bins
d_num_doppler_bins = 0;
for (int doppler = static_cast<int>(-d_doppler_max);
doppler <= static_cast<int>(d_doppler_max);
doppler += d_doppler_step)
{
d_num_doppler_bins++;
}
// Create the carrier Doppler wipeoff signals
d_grid_doppler_wipeoffs = std::vector<std::vector<gr_complex>>(d_num_doppler_bins, std::vector<gr_complex>(d_fft_size));
if (d_opencl == 0)
{
d_cl_buffer_grid_doppler_wipeoffs = new cl::Buffer *[d_num_doppler_bins];
}
for (uint32_t doppler_index = 0; doppler_index < d_num_doppler_bins; doppler_index++)
{
int doppler = -static_cast<int>(d_doppler_max) + d_doppler_step * doppler_index;
float phase_step_rad = static_cast<float>(TWO_PI) * doppler / static_cast<float>(d_fs_in);
std::array<float, 1> _phase{};
volk_gnsssdr_s32f_sincos_32fc(d_grid_doppler_wipeoffs[doppler_index].data(), -phase_step_rad, _phase.data(), d_fft_size);
if (d_opencl == 0)
{
d_cl_buffer_grid_doppler_wipeoffs[doppler_index] =
new cl::Buffer(d_cl_context, CL_MEM_READ_WRITE, sizeof(gr_complex) * d_fft_size);
d_cl_queue->enqueueWriteBuffer(*(d_cl_buffer_grid_doppler_wipeoffs[doppler_index]),
CL_TRUE, 0, sizeof(gr_complex) * d_fft_size,
d_grid_doppler_wipeoffs[doppler_index].data());
}
}
// zero padding in buffer_1 (FFT input)
if (d_opencl == 0)
{
d_cl_queue->enqueueWriteBuffer(*d_cl_buffer_1, CL_TRUE, sizeof(gr_complex) * d_fft_size,
sizeof(gr_complex) * (d_fft_size_pow2 - d_fft_size), d_zero_vector.data());
}
}
void pcps_opencl_acquisition_cc::set_local_code(std::complex<float> *code)
{
if (d_opencl == 0)
{
d_cl_queue->enqueueWriteBuffer(*d_cl_buffer_2, CL_TRUE, 0,
sizeof(gr_complex) * d_fft_size, code);
d_cl_queue->enqueueWriteBuffer(*d_cl_buffer_2, CL_TRUE, sizeof(gr_complex) * d_fft_size,
sizeof(gr_complex) * (d_fft_size_pow2 - 2 * d_fft_size),
d_zero_vector.data());
d_cl_queue->enqueueWriteBuffer(*d_cl_buffer_2, CL_TRUE, sizeof(gr_complex) * (d_fft_size_pow2 - d_fft_size),
sizeof(gr_complex) * d_fft_size, code);
clFFT_ExecuteInterleaved((*d_cl_queue)(), d_cl_fft_plan, d_cl_fft_batch_size,
clFFT_Forward, (*d_cl_buffer_2)(), (*d_cl_buffer_2)(),
0, nullptr, nullptr);
// Conjucate the local code
cl::Kernel kernel = cl::Kernel(d_cl_program, "conj_vector");
kernel.setArg(0, *d_cl_buffer_2); // input
kernel.setArg(1, *d_cl_buffer_fft_codes); // output
d_cl_queue->enqueueNDRangeKernel(kernel, cl::NullRange, cl::NDRange(d_fft_size_pow2), cl::NullRange);
}
else
{
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.data(), d_fft_if->get_outbuf(), d_fft_size);
}
}
void pcps_opencl_acquisition_cc::acquisition_core_volk()
{
// initialize acquisition algorithm
int doppler;
uint32_t indext = 0;
float magt = 0.0;
float fft_normalization_factor = static_cast<float>(d_fft_size) * static_cast<float>(d_fft_size);
uint64_t 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.data(), d_in_buffer[d_well_count].data(), d_fft_size);
volk_32f_accumulator_s32f(&d_input_power, d_magnitude.data(), d_fft_size);
d_input_power /= static_cast<float>(d_fft_size);
// 2- Doppler frequency search loop
for (uint32_t doppler_index = 0; doppler_index < d_num_doppler_bins; doppler_index++)
{
// doppler search steps
doppler = -static_cast<int>(d_doppler_max) + d_doppler_step * doppler_index;
volk_32fc_x2_multiply_32fc(d_fft_if->get_inbuf(), d_in_buffer[d_well_count].data(),
d_grid_doppler_wipeoffs[doppler_index].data(), 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.data(), d_fft_size);
// compute the inverse FFT
d_ifft->execute();
// Search maximum
volk_32fc_magnitude_squared_32f(d_magnitude.data(), d_ifft->get_outbuf(), d_fft_size);
volk_gnsssdr_32f_index_max_32u(&indext, d_magnitude.data(), 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 = static_cast<double>(indext % d_samples_per_code);
d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
d_gnss_synchro->Acq_samplestamp_samples = samplestamp;
d_gnss_synchro->Acq_doppler_step = d_doppler_step;
// 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[0] << d_gnss_synchro->Signal[1] << "_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(reinterpret_cast<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;
}
void pcps_opencl_acquisition_cc::acquisition_core_opencl()
{
// initialize acquisition algorithm
int doppler;
uint32_t indext = 0;
float magt = 0.0;
float fft_normalization_factor = (static_cast<float>(d_fft_size_pow2) * static_cast<float>(d_fft_size)); // This works, but I am not sure why.
uint64_t samplestamp = d_sample_counter_buffer[d_well_count];
d_input_power = 0.0;
d_mag = 0.0;
// write input vector in buffer of OpenCL device
d_cl_queue->enqueueWriteBuffer(*d_cl_buffer_in, CL_TRUE, 0, sizeof(gr_complex) * d_fft_size, d_in_buffer[d_well_count].data());
d_well_count++;
// struct timeval tv;
// long long int begin = 0;
// long long int end = 0;
// gettimeofday(&tv, NULL);
// begin = tv.tv_sec *1e6 + tv.tv_usec;
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.data(), d_in_buffer[d_well_count].data(), d_fft_size);
volk_32f_accumulator_s32f(&d_input_power, d_magnitude.data(), d_fft_size);
d_input_power /= static_cast<float>(d_fft_size);
cl::Kernel kernel;
// 2- Doppler frequency search loop
for (uint32_t doppler_index = 0; doppler_index < d_num_doppler_bins; doppler_index++)
{
// doppler search steps
doppler = -static_cast<int>(d_doppler_max) + d_doppler_step * doppler_index;
// Multiply input signal with doppler wipe-off
kernel = cl::Kernel(d_cl_program, "mult_vectors");
kernel.setArg(0, *d_cl_buffer_in); // input 1
kernel.setArg(1, *d_cl_buffer_grid_doppler_wipeoffs[doppler_index]); // input 2
kernel.setArg(2, *d_cl_buffer_1); // output
d_cl_queue->enqueueNDRangeKernel(kernel, cl::NullRange, cl::NDRange(d_fft_size),
cl::NullRange);
// In the previous operation, we store the result in the first d_fft_size positions
// of d_cl_buffer_1. The rest d_fft_size_pow2-d_fft_size already have zeros
// (zero-padding is made in init() for optimization purposes).
clFFT_ExecuteInterleaved((*d_cl_queue)(), d_cl_fft_plan, d_cl_fft_batch_size,
clFFT_Forward, (*d_cl_buffer_1)(), (*d_cl_buffer_2)(),
0, nullptr, nullptr);
// Multiply carrier wiped--off, Fourier transformed incoming signal
// with the local FFT'd code reference
kernel = cl::Kernel(d_cl_program, "mult_vectors");
kernel.setArg(0, *d_cl_buffer_2); // input 1
kernel.setArg(1, *d_cl_buffer_fft_codes); // input 2
kernel.setArg(2, *d_cl_buffer_2); // output
d_cl_queue->enqueueNDRangeKernel(kernel, cl::NullRange, cl::NDRange(d_fft_size_pow2),
cl::NullRange);
// compute the inverse FFT
clFFT_ExecuteInterleaved((*d_cl_queue)(), d_cl_fft_plan, d_cl_fft_batch_size,
clFFT_Inverse, (*d_cl_buffer_2)(), (*d_cl_buffer_2)(),
0, nullptr, nullptr);
// Compute magnitude
kernel = cl::Kernel(d_cl_program, "magnitude_squared");
kernel.setArg(0, *d_cl_buffer_2); // input 1
kernel.setArg(1, *d_cl_buffer_magnitude); // output
d_cl_queue->enqueueNDRangeKernel(kernel, cl::NullRange, cl::NDRange(d_fft_size),
cl::NullRange);
// This is the only function that blocks this thread until all previously enqueued
// OpenCL commands are completed.
d_cl_queue->enqueueReadBuffer(*d_cl_buffer_magnitude, CL_TRUE, 0,
sizeof(float) * d_fft_size, d_magnitude.data());
// Search maximum
// @TODO: find an efficient way to search the maximum with OpenCL in the GPU.
volk_gnsssdr_32f_index_max_32u(&indext, d_magnitude.data(), 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 = static_cast<double>(indext % d_samples_per_code);
d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
d_gnss_synchro->Acq_samplestamp_samples = samplestamp;
d_gnss_synchro->Acq_doppler_step = d_doppler_step;
// 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[0] << d_gnss_synchro->Signal[1] << "_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(reinterpret_cast<char *>(d_ifft->get_outbuf()), n); // write directly |abs(x)|^2 in this Doppler bin?
d_dump_file.close();
}
}
// gettimeofday(&tv, NULL);
// end = tv.tv_sec *1e6 + tv.tv_usec;
// std::cout << "Acq time = " << (end-begin) << " us\n";
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;
}
void pcps_opencl_acquisition_cc::set_state(int state)
{
d_state = state;
if (d_state == 1)
{
d_gnss_synchro->Acq_delay_samples = 0.0;
d_gnss_synchro->Acq_doppler_hz = 0.0;
d_gnss_synchro->Acq_samplestamp_samples = 0ULL;
d_gnss_synchro->Acq_doppler_step = 0U;
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();
}
else if (d_state == 0)
{
}
else
{
LOG(ERROR) << "State can only be set to 0 or 1";
}
}
int pcps_opencl_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 = 0ULL;
d_gnss_synchro->Acq_doppler_step = 0U;
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 += static_cast<uint64_t>(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.
uint32_t num_dwells = std::min(static_cast<int>(d_max_dwells - d_in_dwell_count), ninput_items[0]);
for (uint32_t i = 0; i < num_dwells; i++)
{
memcpy(d_in_buffer[d_in_dwell_count++].data(), static_cast<const gr_complex *>(input_items[i]),
sizeof(gr_complex) * d_fft_size);
d_sample_counter += static_cast<uint64_t>(d_fft_size);
d_sample_counter_buffer.push_back(d_sample_counter);
}
if (ninput_items[0] > static_cast<int>(num_dwells))
{
d_sample_counter += static_cast<uint64_t>(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 += static_cast<uint64_t>(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;
if (d_opencl == 0)
{ // Use OpenCL implementation
boost::thread(&pcps_opencl_acquisition_cc::acquisition_core_opencl, this);
}
else
{ // Use Volk implementation
boost::thread(&pcps_opencl_acquisition_cc::acquisition_core_volk, this);
}
}
break;
}
case 2:
{
// Declare positive acquisition using a message port
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 += static_cast<uint64_t>(d_fft_size * ninput_items[0]); // sample counter
acquisition_message = 1;
this->message_port_pub(pmt::mp("events"), pmt::from_long(acquisition_message));
// Copy and push current Gnss_Synchro to monitor queue
if (d_enable_monitor_output)
{
auto **out = reinterpret_cast<Gnss_Synchro **>(&output_items[0]);
Gnss_Synchro current_synchro_data = Gnss_Synchro();
current_synchro_data = *d_gnss_synchro;
*out[0] = current_synchro_data;
noutput_items = 1; // Number of Gnss_Synchro objects produced
}
break;
}
case 3:
{
// Declare negative acquisition using a message port
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 += static_cast<uint64_t>(d_fft_size * ninput_items[0]); // sample counter
acquisition_message = 2;
this->message_port_pub(pmt::mp("events"), pmt::from_long(acquisition_message));
break;
}
}
consume_each(ninput_items[0]);
return noutput_items;
}
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