mirror of https://github.com/gnss-sdr/gnss-sdr
361 lines
13 KiB
C++
361 lines
13 KiB
C++
/*!
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* \file gps_l1_ca_tong_pcps_acquisition_cc.cc
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* \brief Brief description of the file here
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* \author Luis Esteve, 2011. luis(at)epsilon-formacion.com
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*
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* Detailed description of the file here if needed.
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*
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* -------------------------------------------------------------------------
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*
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* Copyright (C) 2010-2011 (see AUTHORS file for a list of contributors)
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*
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* GNSS-SDR is a software defined Global Navigation
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* Satellite Systems receiver
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*
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* This file is part of GNSS-SDR.
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*
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* GNSS-SDR is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* at your option) any later version.
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*
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* GNSS-SDR is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNSS-SDR. If not, see <http://www.gnu.org/licenses/>.
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*
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* -------------------------------------------------------------------------
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*/
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#include "gps_l1_ca_tong_pcps_acquisition_cc.h"
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#include "gps_sdr_signal_processing.h"
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#include "control_message_factory.h"
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#include "gps_sdr_x86.h"
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#include <gnuradio/gr_io_signature.h>
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#include <sstream>
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#include <glog/log_severity.h>
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#include <glog/logging.h>
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using google::LogMessage;
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gps_l1_ca_tong_pcps_acquisition_cc_sptr gps_l1_ca_tong_pcps_make_acquisition_cc(
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unsigned int sampled_ms, unsigned int doppler_max, long freq,
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long fs_in, int samples_per_ms, gr_msg_queue_sptr queue, bool dump,
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std::string dump_filename)
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{
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return gps_l1_ca_tong_pcps_acquisition_cc_sptr(
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new gps_l1_ca_tong_pcps_acquisition_cc(sampled_ms, doppler_max,
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freq, fs_in, samples_per_ms, queue, dump, dump_filename));
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}
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gps_l1_ca_tong_pcps_acquisition_cc::gps_l1_ca_tong_pcps_acquisition_cc(
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unsigned int sampled_ms, unsigned int doppler_max, long freq,
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long fs_in, int samples_per_ms, gr_msg_queue_sptr queue, bool dump,
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std::string dump_filename) :
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gr_block("gps_l1_ca_tong_pcps_acquisition_cc", gr_make_io_signature(1, 1,
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sizeof(gr_complex) * samples_per_ms), gr_make_io_signature(0, 0,
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sizeof(gr_complex) * samples_per_ms))
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{
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// SAMPLE COUNTER
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d_sample_counter = 0;
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d_active = false;
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d_dump = dump;
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d_queue = queue;
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d_dump_filename = dump_filename;
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d_freq = freq;
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d_fs_in = fs_in;
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d_samples_per_ms = samples_per_ms;
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d_sampled_ms = sampled_ms;
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d_doppler_max = doppler_max;
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d_satellite = 0;
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d_samples = d_sampled_ms * d_samples_per_ms;
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d_doppler_freq = 0.0;
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d_code_phase = 0;
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d_mag = 0.0;
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d_noise_power = 0.0;
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d_fbins = 0;
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d_doppler = 0;
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d_pfa = 0.2;
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d_A = 8;
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d_B = 1;
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d_max_dwells = 15;
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d_K = d_B;
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d_if_sin = new gr_complex[d_samples];
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d_fft_codes = (gr_complex*)malloc(sizeof(gr_complex) * d_samples_per_ms);
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// Direct FFT
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d_fft_if = new gri_fft_complex(d_samples, true);
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// Inverse FFT
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d_ifft = new gri_fft_complex(d_samples, false);
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d_ca_codes = new gr_complex[d_samples];
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d_aux_ca_code = new gr_complex[d_samples];
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//generates a unused PRN code to calculate the noise envelope
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code_gen_complex_sampled(d_aux_ca_code, 33, d_fs_in, 0);
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DLOG(INFO) << "fs in " << d_fs_in;
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DLOG(INFO) << "samples per ms " << d_samples_per_ms;
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DLOG(INFO) << "doppler max " << d_doppler_max;
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DLOG(INFO) << "freq " << d_freq;
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DLOG(INFO) << "satellite " << d_satellite;
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DLOG(INFO) << "sampled_ms " << d_sampled_ms;
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DLOG(INFO) << "Samples_for_processing " << d_samples;
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DLOG(INFO) << "dump filename " << d_dump_filename;
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DLOG(INFO) << "dump " << d_dump;
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}
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gps_l1_ca_tong_pcps_acquisition_cc::~gps_l1_ca_tong_pcps_acquisition_cc()
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{
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delete[] d_if_sin;
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delete[] d_ca_codes;
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delete[] d_aux_ca_code;
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delete d_fft_if;
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delete d_ifft;
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if (d_dump)
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{
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d_dump_file.close();
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}
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}
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void gps_l1_ca_tong_pcps_acquisition_cc::set_satellite(unsigned int satellite)
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{
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d_satellite = satellite;
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d_code_phase = 0;
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d_doppler_freq = 0;
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d_mag = 0.0;
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d_noise_power = 0.0;
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// The GPS codes are generated on the fly using a custom version of the GPS code generator
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//! \TODO In-memory codes instead of generated on the fly
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code_gen_complex_sampled(d_fft_if->get_inbuf(), satellite, d_fs_in, 0);
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d_fft_if->execute(); // We need the FFT of GPS C/A code
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//Conjugate the local code
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//! \TODO Optimize it ! Try conj() or Armadillo
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for (unsigned int i = 0; i < d_samples; i++)
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{
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d_fft_codes[i] = std::complex<float>(
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d_fft_if->get_outbuf()[i].real(),
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-d_fft_if->get_outbuf()[i].imag());
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}
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}
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signed int gps_l1_ca_tong_pcps_acquisition_cc::prn_code_phase()
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{
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return d_code_phase;
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}
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int gps_l1_ca_tong_pcps_acquisition_cc::general_work(int noutput_items,
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gr_vector_int &ninput_items, gr_vector_const_void_star &input_items,
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gr_vector_void_star &output_items)
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{
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if (!d_active)
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{
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// sample counter
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d_sample_counter += d_samples * noutput_items;
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consume_each(noutput_items);
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}
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else
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{
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d_sample_counter += d_samples;
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// initialize acquisition algorithm
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bool positive_acquisition = false;
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int acquisition_message = -1; //0=STOP_CHANNEL 1=ACQ_SUCCEES 2=ACQ_FAIL
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//float noise_envelope = 0.0;
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float vt = 20000;
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//float peak = 0.0;
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float magt = 0.0;
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unsigned int max_freq_step = 2 * (unsigned int)(d_doppler_max
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/ d_doppler_step);
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unsigned int indext = 0;
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// Get the input samples pointer
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const gr_complex *in = (const gr_complex *)input_items[0];
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// aux vars
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std::stringstream filename;
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//unsigned int consume_items = 1;
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// complex file write
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// std::streamsize n = 2 * sizeof(float) * (d_samples);
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// 1 - Compute the input noise envelope estimation and the threshold vt
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// sine_gen_complex( d_if_sin, d_freq + doppler, d_fs_in, d_samples );
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//
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// noise_envelope = calculate_envelope( in, d_aux_ca_code, d_if_sin );
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// vt = noise_envelope * sqrt( -2 * log( d_pfa ) );
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// 1- Compute the input signal power estimation
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for (unsigned int i = 0; i < d_samples; i++)
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{
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d_noise_power += std::abs(in[i]);
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}
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d_noise_power = sqrt(d_noise_power / (float)d_samples);
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//2. Perform the carrier wipe-off
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sine_gen_complex(d_if_sin, d_freq + d_doppler, d_fs_in, d_samples);
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for (unsigned int i = 0; i < d_samples; i++)
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{
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d_fft_if->get_inbuf()[i] = in[i] * d_if_sin[i];
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}
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//3- Perform the FFT-based circular convolution (parallel time search)
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d_fft_if->execute();
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//TODO Optimize me: use Armadillo!
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for (unsigned int i = 0; i < d_samples; i++)
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{
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d_ifft->get_inbuf()[i] = d_fft_if->get_outbuf()[i]
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* d_fft_codes[i];
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}
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d_ifft->execute();
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x86_gr_complex_mag(d_ifft->get_outbuf(), d_samples); // d_ifft->get_outbuf()=|abs(·)|^2 and the array is converted from CPX->Float
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x86_float_max((float*)d_ifft->get_outbuf(), &d_indext, &magt,
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d_samples); // find max of |abs(·)|^2 -> index and magt
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magt = sqrt(magt) / (float)d_samples;
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d_test_statistics = magt / d_noise_power;
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LOG_AT_LEVEL(INFO) << "Channel: " << d_channel
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<< ", doing Tong PCSS acquisition of satellite: "
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<< d_satellite << ", sample stamp: " << d_sample_counter
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<< ", bin_freq " << d_doppler << ", doppler_max: "
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<< d_doppler_max << ", K " << d_K << ", sigma: "
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<< d_noise_power << ", mag: " << d_test_statistics
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<< ", vt: " << vt;
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if ((d_test_statistics > vt) && (indext = d_indext))
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{
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d_K++;
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if (d_K == d_A)
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{
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d_code_phase = d_indext;
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positive_acquisition = true;
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d_doppler_freq = d_doppler;
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d_acq_sample_stamp = d_sample_counter;
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LOG_AT_LEVEL(INFO) << "positive acquisition";
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LOG_AT_LEVEL(INFO) << "satellite " << d_satellite;
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LOG_AT_LEVEL(INFO) << "sample_stamp " << d_sample_counter;
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LOG_AT_LEVEL(INFO) << "test statistics value "
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<< d_test_statistics;
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LOG_AT_LEVEL(INFO) << "test statistics threshold " << vt;
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LOG_AT_LEVEL(INFO) << "code phase " << d_code_phase;
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LOG_AT_LEVEL(INFO) << "doppler " << d_doppler_freq;
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LOG_AT_LEVEL(INFO) << "magnitude " << magt;
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LOG_AT_LEVEL(INFO) << "input signal power " << d_noise_power;
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d_dwells = 0;
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d_active = false;
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}
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else d_dwells++;
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}
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else
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{
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d_K--;
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if ((d_K == 0) || (d_dwells > d_max_dwells))
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{
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d_K = d_B;
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d_dwells = 0;
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d_fbins++;
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if (d_fbins > max_freq_step)
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{
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d_fbins = 0;
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LOG_AT_LEVEL(INFO) << "negative acquisition";
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LOG_AT_LEVEL(INFO) << "satellite " << d_satellite;
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LOG_AT_LEVEL(INFO) << "sample_stamp" << d_sample_counter;
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LOG_AT_LEVEL(INFO) << "test statistics value "
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<< d_test_statistics;
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LOG_AT_LEVEL(INFO) << "test statistics threshold " << vt;
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LOG_AT_LEVEL(INFO) << "input signal power "
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<< d_noise_power;
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d_active = false;
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}
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else
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{
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d_doppler = d_doppler + pow(-1, d_fbins + 1) * d_fbins
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* d_doppler_step;
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}
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}
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else d_dwells++;
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}
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// Record results to files
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// if( d_dump )
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// {
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// filename.str( "" );
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// filename << "./data/fft_" << doppler << "_.dat";
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// std::cout << filename.str().c_str();
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// std::cout << ".\n";
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// d_dump_file.open( filename.str().c_str(), std::ios::out
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// | std::ios::binary );
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// d_dump_file.write( (char*) d_ifft->get_outbuf(), n ); //write directly |abs(·)|^2 in this Doppler bin
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// d_dump_file.close();
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// }
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if (d_active == false)
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{
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if (positive_acquisition)
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{
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acquisition_message = 1;
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}
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else
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{
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acquisition_message = 2;
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}
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d_channel_internal_queue->push(acquisition_message);
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}
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consume_each(1);
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}
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return 0;
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}
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float gps_l1_ca_tong_pcps_acquisition_cc::calculate_envelope(
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const gr_complex* _input_signal, std::complex<float>* _local_code,
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std::complex<float>* _local_if_sin)
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{
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float mag = 0.0;
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std::complex<float> tmp_cpx = 0.0;
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//std::cout << "tmp_cpx " << tmp_cpx << std::endl;
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for (unsigned int i = 0; i < d_samples; i++)
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{
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tmp_cpx = tmp_cpx + _input_signal[i] * _local_code[i]
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* _local_if_sin[i];
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}
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//std::cout << "tmp_cpx " << tmp_cpx << std::endl;
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mag = abs(tmp_cpx);
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return mag;
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}
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