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gnss-sdr/src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition_fpga.cc
Marc Majoral 2b46c79ba7 optimized the process of computing and writing the fft of the local code to the acquisition HW accelerator.
The writing of the local code is still performed by processor instructions in a loop.
THe FPGA L2 classes were updated accordingly.
2019-03-26 12:26:08 +01:00

301 lines
11 KiB
C++

/*!
* \file galileo_e5a_pcps_acquisition_fpga.cc
* \brief Adapts a PCPS acquisition block to an AcquisitionInterface for
* Galileo E5a data and pilot Signals for the FPGA
* \author Marc Majoral, 2019. mmajoral(at)cttc.es
*
* -------------------------------------------------------------------------
*
* Copyright (C) 2010-2019 (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 "galileo_e5a_pcps_acquisition_fpga.h"
#include "Galileo_E5a.h"
#include "configuration_interface.h"
#include "galileo_e5_signal_processing.h"
#include "gnss_sdr_flags.h"
#include "gnss_synchro.h"
#include <glog/logging.h>
#include <gnuradio/fft/fft.h> // for fft_complex
#include <gnuradio/gr_complex.h> // for gr_complex
#include <volk/volk.h> // for volk_32fc_conjugate_32fc
#include <volk_gnsssdr/volk_gnsssdr.h>
#include <cmath> // for abs, pow, floor
#include <complex> // for complex
#include <cstring> // for strcpy, memcpy
#define QUANT_BITS_LOCAL_CODE 16
#define SELECT_LSBits 0x0000FFFF // Select the 10 LSbits out of a 20-bit word
#define SELECT_MSBbits 0xFFFF0000 // Select the 10 MSbits out of a 20-bit word
#define SELECT_ALL_CODE_BITS 0xFFFFFFFF // Select a 20 bit word
#define SHL_CODE_BITS 65536 // shift left by 10 bits
GalileoE5aPcpsAcquisitionFpga::GalileoE5aPcpsAcquisitionFpga(ConfigurationInterface* configuration,
const std::string& role,
unsigned int in_streams,
unsigned int out_streams) : role_(role),
in_streams_(in_streams),
out_streams_(out_streams)
{
pcpsconf_fpga_t acq_parameters;
configuration_ = configuration;
std::string default_dump_filename = "../data/acquisition.dat";
DLOG(INFO) << "Role " << role;
int64_t fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 32000000);
int64_t fs_in = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
acq_parameters.repeat_satellite = configuration_->property(role + ".repeat_satellite", false);
DLOG(INFO) << role << " satellite repeat = " << acq_parameters.repeat_satellite;
uint32_t downsampling_factor = configuration_->property(role + ".downsampling_factor", 1);
acq_parameters.downsampling_factor = downsampling_factor;
fs_in = fs_in / downsampling_factor;
acq_parameters.fs_in = fs_in;
doppler_max_ = configuration_->property(role + ".doppler_max", 5000);
if (FLAGS_doppler_max != 0) doppler_max_ = FLAGS_doppler_max;
acq_parameters.doppler_max = doppler_max_;
uint32_t sampled_ms = configuration_->property(role + ".coherent_integration_time_ms", 1);
acq_parameters.sampled_ms = sampled_ms;
acq_pilot_ = configuration_->property(role + ".acquire_pilot", false);
acq_iq_ = configuration_->property(role + ".acquire_iq", false);
if (acq_iq_)
{
acq_pilot_ = false;
}
auto code_length = static_cast<uint32_t>(std::round(static_cast<double>(fs_in) / GALILEO_E5A_CODE_CHIP_RATE_HZ * static_cast<double>(GALILEO_E5A_CODE_LENGTH_CHIPS)));
acq_parameters.code_length = code_length;
// The FPGA can only use FFT lengths that are a power of two.
float nbits = ceilf(log2f((float)code_length * 2));
uint32_t nsamples_total = pow(2, nbits);
uint32_t select_queue_Fpga = configuration_->property(role + ".select_queue_Fpga", 1);
acq_parameters.select_queue_Fpga = select_queue_Fpga;
std::string default_device_name = "/dev/uio0";
std::string device_name = configuration_->property(role + ".devicename", default_device_name);
acq_parameters.device_name = device_name;
acq_parameters.samples_per_ms = nsamples_total / sampled_ms;
acq_parameters.samples_per_code = nsamples_total;
acq_parameters.excludelimit = static_cast<unsigned int>(1 + ceil((1.0 / GALILEO_E5A_CODE_CHIP_RATE_HZ) * static_cast<float>(fs_in)));
// compute all the GALILEO E5 PRN Codes (this is done only once in the class constructor in order to avoid re-computing the PRN codes every time
// a channel is assigned)
auto* fft_if = new gr::fft::fft_complex(nsamples_total, true); // Direct FFT
auto* code = new std::complex<float>[nsamples_total]; // buffer for the local code
auto* fft_codes_padded = static_cast<gr_complex*>(volk_gnsssdr_malloc(nsamples_total * sizeof(gr_complex), volk_gnsssdr_get_alignment()));
//d_all_fft_codes_ = new lv_16sc_t[nsamples_total * GALILEO_E5A_NUMBER_OF_CODES]; // memory containing all the possible fft codes for PRN 0 to 32
d_all_fft_codes_ = new uint32_t[(nsamples_total * GALILEO_E5A_NUMBER_OF_CODES)]; // memory containing all the possible fft codes for PRN 0 to 32
float max; // temporary maxima search
int32_t tmp, tmp2, local_code, fft_data;
for (uint32_t PRN = 1; PRN <= GALILEO_E5A_NUMBER_OF_CODES; PRN++)
{
char signal_[3];
if (acq_iq_)
{
strcpy(signal_, "5X");
}
else if (acq_pilot_)
{
strcpy(signal_, "5Q");
}
else
{
strcpy(signal_, "5I");
}
galileo_e5_a_code_gen_complex_sampled(code, signal_, PRN, fs_in, 0);
for (uint32_t s = code_length; s < 2 * code_length; s++)
{
code[s] = code[s - code_length];
}
// fill in zero padding
for (uint32_t s = 2 * code_length; s < nsamples_total; s++)
{
code[s] = std::complex<float>(0.0, 0.0);
}
memcpy(fft_if->get_inbuf(), code, sizeof(gr_complex) * nsamples_total); // copy to FFT buffer
fft_if->execute(); // Run the FFT of local code
volk_32fc_conjugate_32fc(fft_codes_padded, fft_if->get_outbuf(), nsamples_total); // conjugate values
max = 0; // initialize maximum value
for (uint32_t i = 0; i < nsamples_total; i++) // search for maxima
{
if (std::abs(fft_codes_padded[i].real()) > max)
{
max = std::abs(fft_codes_padded[i].real());
}
if (std::abs(fft_codes_padded[i].imag()) > max)
{
max = std::abs(fft_codes_padded[i].imag());
}
}
// map the FFT to the dynamic range of the fixed point values an copy to buffer containing all FFTs
// and package codes in a format that is ready to be written to the FPGA
for (uint32_t i = 0; i < nsamples_total; i++)
{
tmp = static_cast<int32_t>(floor(fft_codes_padded[i].real() * (pow(2, QUANT_BITS_LOCAL_CODE - 1) - 1) / max));
tmp2 = static_cast<int32_t>(floor(fft_codes_padded[i].imag() * (pow(2, QUANT_BITS_LOCAL_CODE - 1) - 1) / max));
local_code = (tmp & SELECT_LSBits) | ((tmp2 * SHL_CODE_BITS) & SELECT_MSBbits); // put together the real part and the imaginary part
fft_data = local_code & SELECT_ALL_CODE_BITS;
d_all_fft_codes_[i + (nsamples_total * (PRN - 1))] = fft_data;
// d_all_fft_codes_[i + nsamples_total * (PRN - 1)] = lv_16sc_t(static_cast<int32_t>(floor(fft_codes_padded[i].real() * (pow(2, QUANT_BITS_LOCAL_CODE - 1) - 1) / max)),
// static_cast<int32_t>(floor(fft_codes_padded[i].imag() * (pow(2, QUANT_BITS_LOCAL_CODE - 1) - 1) / max)));
}
}
acq_parameters.all_fft_codes = d_all_fft_codes_;
// reference for the FPGA FFT-IFFT attenuation factor
acq_parameters.total_block_exp = configuration_->property(role + ".total_block_exp", 13);
acq_parameters.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
acq_parameters.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
acq_parameters.make_2_steps = configuration_->property(role + ".make_two_steps", false);
acquisition_fpga_ = pcps_make_acquisition_fpga(acq_parameters);
channel_ = 0;
doppler_step_ = 0;
gnss_synchro_ = nullptr;
channel_fsm_ = nullptr;
// temporary buffers that we can delete
delete[] code;
delete fft_if;
delete[] fft_codes_padded;
}
GalileoE5aPcpsAcquisitionFpga::~GalileoE5aPcpsAcquisitionFpga()
{
delete[] d_all_fft_codes_;
}
void GalileoE5aPcpsAcquisitionFpga::stop_acquisition()
{
// this command causes the SW to reset the HW.
acquisition_fpga_->reset_acquisition();
}
void GalileoE5aPcpsAcquisitionFpga::set_threshold(float threshold)
{
DLOG(INFO) << "Channel " << channel_ << " Threshold = " << threshold;
acquisition_fpga_->set_threshold(threshold);
}
void GalileoE5aPcpsAcquisitionFpga::set_doppler_max(unsigned int doppler_max)
{
doppler_max_ = doppler_max;
acquisition_fpga_->set_doppler_max(doppler_max_);
}
void GalileoE5aPcpsAcquisitionFpga::set_doppler_step(unsigned int doppler_step)
{
doppler_step_ = doppler_step;
acquisition_fpga_->set_doppler_step(doppler_step_);
}
void GalileoE5aPcpsAcquisitionFpga::set_gnss_synchro(Gnss_Synchro* gnss_synchro)
{
gnss_synchro_ = gnss_synchro;
acquisition_fpga_->set_gnss_synchro(gnss_synchro_);
}
signed int GalileoE5aPcpsAcquisitionFpga::mag()
{
return acquisition_fpga_->mag();
}
void GalileoE5aPcpsAcquisitionFpga::init()
{
acquisition_fpga_->init();
}
void GalileoE5aPcpsAcquisitionFpga::set_local_code()
{
acquisition_fpga_->set_local_code();
}
void GalileoE5aPcpsAcquisitionFpga::reset()
{
acquisition_fpga_->set_active(true);
}
void GalileoE5aPcpsAcquisitionFpga::set_state(int state)
{
acquisition_fpga_->set_state(state);
}
void GalileoE5aPcpsAcquisitionFpga::connect(gr::top_block_sptr top_block)
{
if (top_block)
{ /* top_block is not null */
};
// Nothing to connect
}
void GalileoE5aPcpsAcquisitionFpga::disconnect(gr::top_block_sptr top_block)
{
if (top_block)
{ /* top_block is not null */
};
// Nothing to disconnect
}
gr::basic_block_sptr GalileoE5aPcpsAcquisitionFpga::get_left_block()
{
return nullptr;
}
gr::basic_block_sptr GalileoE5aPcpsAcquisitionFpga::get_right_block()
{
return nullptr;
}