mirror of https://github.com/gnss-sdr/gnss-sdr
117 lines
4.2 KiB
C++
117 lines
4.2 KiB
C++
/*!
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* \file preamble_correlator_test.cc
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* \brief This file implements tests for preamble detection.
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* \author Carles Fernandez-Prades, 2020. cfernandez(at)cttc.es
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*
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*
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* -------------------------------------------------------------------------
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*
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* Copyright (C) 2010-2019 (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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* SPDX-License-Identifier: GPL-3.0-or-later
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*
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* -------------------------------------------------------------------------
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*/
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#include "GPS_L1_CA.h"
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#include <algorithm>
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#include <array>
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#include <chrono>
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#include <cstdint>
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#include <functional> // for std::plus
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#include <numeric>
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#include <random>
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#include <vector>
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TEST(PreambleCorrelationTest, TestMethods)
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{
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int64_t n_iter = 100000;
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int32_t corr_value = 0;
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int32_t corr_value2 = 0;
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int32_t corr_value3 = 0;
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int32_t sum_corr1 = 0;
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int32_t sum_corr2 = 0;
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int32_t sum_corr3 = 0;
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std::vector<float> d_symbol_history(GPS_CA_PREAMBLE_LENGTH_SYMBOLS, 0.0);
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std::array<int32_t, GPS_CA_PREAMBLE_LENGTH_BITS> d_preamble_samples{};
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std::chrono::time_point<std::chrono::system_clock> start, end, start2, end2, start3, end3;
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// fill the inputs
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std::random_device rd;
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std::default_random_engine e2(rd());
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std::uniform_real_distribution<> dist(-1.0, 1.0);
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std::generate(d_symbol_history.begin(), d_symbol_history.end(), [&dist, &e2]() { return dist(e2); });
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std::generate(d_preamble_samples.begin(), d_preamble_samples.end(), [n = 0]() mutable { return (GPS_CA_PREAMBLE[n++] == '1' ? 1 : -1); });
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// Compute correlation, method 1
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start = std::chrono::system_clock::now();
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for (int64_t iter = 0; iter < n_iter; iter++)
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{
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corr_value = 0;
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for (int32_t i = 0; i < GPS_CA_PREAMBLE_LENGTH_BITS; i++)
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{
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if (d_symbol_history[i] < 0.0)
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{
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corr_value -= d_preamble_samples[i];
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}
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else
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{
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corr_value += d_preamble_samples[i];
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}
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}
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sum_corr1 += corr_value;
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}
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end = std::chrono::system_clock::now();
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// Compute correlation, method 2
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start2 = std::chrono::system_clock::now();
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for (int64_t iter = 0; iter < n_iter; iter++)
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{
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corr_value2 = std::accumulate(d_symbol_history.begin(),
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d_symbol_history.begin() + GPS_CA_PREAMBLE_LENGTH_BITS,
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0,
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[&d_preamble_samples, n = 0](float a, float b) mutable { return (b > 0.0 ? a + d_preamble_samples[n++] : a - d_preamble_samples[n++]); });
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sum_corr2 += corr_value2;
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}
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end2 = std::chrono::system_clock::now();
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// Compute correlation, method 3
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start3 = std::chrono::system_clock::now();
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for (int64_t iter = 0; iter < n_iter; iter++)
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{
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corr_value3 = std::inner_product(d_symbol_history.begin(),
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d_symbol_history.begin() + GPS_CA_PREAMBLE_LENGTH_BITS,
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d_preamble_samples.begin(),
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0,
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#if COMPILER_HAS_STD_PLUS_VOID
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std::plus<>(),
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#else
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std::plus<float>(),
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#endif
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sum_corr3 += corr_value3;
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}
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end3 = std::chrono::system_clock::now();
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std::chrono::duration<double> elapsed_seconds = end - start;
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std::chrono::duration<double> elapsed_seconds2 = end2 - start2;
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std::chrono::duration<double> elapsed_seconds3 = end3 - start3;
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EXPECT_EQ(corr_value, corr_value2);
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EXPECT_EQ(sum_corr1, sum_corr2);
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EXPECT_EQ(corr_value, corr_value3);
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EXPECT_EQ(sum_corr1, sum_corr3);
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std::cout << "Correlation computed with 'C for' : done in " << elapsed_seconds.count() * 1.0e9 / n_iter << " nanoseconds" << std::endl;
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std::cout << "Correlation computed with accumulate : done in " << elapsed_seconds2.count() * 1.0e9 / n_iter << " nanoseconds" << std::endl;
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std::cout << "Correlation computed with inner_product : done in " << elapsed_seconds3.count() * 1.0e9 / n_iter << " nanoseconds" << std::endl;
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}
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