mirror of https://github.com/gnss-sdr/gnss-sdr
144 lines
4.6 KiB
C++
144 lines
4.6 KiB
C++
/*!
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* \file cpu_multicorrelator_real_codes.cc
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* \brief High optimized CPU vector multiTAP correlator class with real-valued local codes
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* \authors <ul>
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* <li> Javier Arribas, 2015. jarribas(at)cttc.es
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* <li> Cillian O'Driscoll, 2017. cillian.odriscoll(at)gmail.com
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* </ul>
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*
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* Class that implements a high optimized vector multiTAP correlator class for CPUs
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*
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* -------------------------------------------------------------------------
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*
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* Copyright (C) 2010-2017 (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 "cpu_multicorrelator_real_codes.h"
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#include <volk_gnsssdr/volk_gnsssdr.h>
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#include <cmath>
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cpu_multicorrelator_real_codes::cpu_multicorrelator_real_codes()
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{
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d_sig_in = nullptr;
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d_local_code_in = nullptr;
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d_shifts_chips = nullptr;
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d_corr_out = nullptr;
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d_local_codes_resampled = nullptr;
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d_code_length_chips = 0;
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d_n_correlators = 0;
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}
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cpu_multicorrelator_real_codes::~cpu_multicorrelator_real_codes()
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{
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if (d_local_codes_resampled != nullptr)
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{
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cpu_multicorrelator_real_codes::free();
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}
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}
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bool cpu_multicorrelator_real_codes::init(
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int max_signal_length_samples,
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int n_correlators)
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{
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// ALLOCATE MEMORY FOR INTERNAL vectors
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size_t size = max_signal_length_samples * sizeof(float);
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d_local_codes_resampled = static_cast<float**>(volk_gnsssdr_malloc(n_correlators * sizeof(float*), volk_gnsssdr_get_alignment()));
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for (int n = 0; n < n_correlators; n++)
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{
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d_local_codes_resampled[n] = static_cast<float*>(volk_gnsssdr_malloc(size, volk_gnsssdr_get_alignment()));
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}
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d_n_correlators = n_correlators;
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return true;
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}
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bool cpu_multicorrelator_real_codes::set_local_code_and_taps(
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int code_length_chips,
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const float* local_code_in,
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float* shifts_chips)
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{
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d_local_code_in = local_code_in;
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d_shifts_chips = shifts_chips;
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d_code_length_chips = code_length_chips;
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return true;
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}
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bool cpu_multicorrelator_real_codes::set_input_output_vectors(std::complex<float>* corr_out, const std::complex<float>* sig_in)
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{
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// Save CPU pointers
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d_sig_in = sig_in;
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d_corr_out = corr_out;
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return true;
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}
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void cpu_multicorrelator_real_codes::update_local_code(int correlator_length_samples, float rem_code_phase_chips, float code_phase_step_chips)
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{
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volk_gnsssdr_32f_xn_resampler_32f_xn(d_local_codes_resampled,
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d_local_code_in,
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rem_code_phase_chips,
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code_phase_step_chips,
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d_shifts_chips,
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d_code_length_chips,
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d_n_correlators,
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correlator_length_samples);
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}
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bool cpu_multicorrelator_real_codes::Carrier_wipeoff_multicorrelator_resampler(
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float rem_carrier_phase_in_rad,
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float phase_step_rad,
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float rem_code_phase_chips,
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float code_phase_step_chips,
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int signal_length_samples)
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{
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update_local_code(signal_length_samples, rem_code_phase_chips, code_phase_step_chips);
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// Regenerate phase at each call in order to avoid numerical issues
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lv_32fc_t phase_offset_as_complex[1];
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phase_offset_as_complex[0] = lv_cmake(std::cos(rem_carrier_phase_in_rad), -std::sin(rem_carrier_phase_in_rad));
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// call VOLK_GNSSSDR kernel
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volk_gnsssdr_32fc_32f_rotator_dot_prod_32fc_xn(d_corr_out, d_sig_in, std::exp(lv_32fc_t(0.0, -phase_step_rad)), phase_offset_as_complex, (const float**)d_local_codes_resampled, d_n_correlators, signal_length_samples);
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return true;
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}
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bool cpu_multicorrelator_real_codes::free()
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{
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// Free memory
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if (d_local_codes_resampled != nullptr)
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{
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for (int n = 0; n < d_n_correlators; n++)
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{
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volk_gnsssdr_free(d_local_codes_resampled[n]);
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}
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volk_gnsssdr_free(d_local_codes_resampled);
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d_local_codes_resampled = nullptr;
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}
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return true;
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}
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