mirror of
https://github.com/gnss-sdr/gnss-sdr
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75 lines
3.6 KiB
C++
75 lines
3.6 KiB
C++
/*
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* \file galileo_utc_model.h
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* \brief Interface of a Galileo UTC MODEL storage
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* \author Javier Arribas, 2013. jarribas(at)cttc.es
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*
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* -----------------------------------------------------------------------------
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*
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* GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
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* This file is part of GNSS-SDR.
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*
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* Copyright (C) 2010-2020 (see AUTHORS file for a list of contributors)
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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 "galileo_utc_model.h"
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#include <cmath>
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double Galileo_Utc_Model::GST_to_UTC_time(double t_e, int32_t WN) const
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{
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double t_Utc;
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double t_Utc_daytime;
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double Delta_t_Utc = 0;
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// Determine if the effectivity time of the leap second event is in the past
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const int32_t weeksToLeapSecondEvent = WN_LSF_6 - (WN % 256);
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if ((weeksToLeapSecondEvent) >= 0) // is not in the past
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{
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// Detect if the effectivity time and user's time is within six hours = 6 * 60 *60 = 21600 s
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const int secondOfLeapSecondEvent = DN_6 * 24 * 60 * 60;
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if (std::abs(t_e - secondOfLeapSecondEvent) > 21600)
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{
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/* 5.1.7a GST->UTC case a
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* Whenever the leap second adjusted time indicated by the WN_LSF and the DN values
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* is not in the past (relative to the user's present time), and the user's
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* present time does not fall in the time span which starts at six hours prior
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* to the effective time and ends at six hours after the effective time,
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* the GST/Utc relationship is given by
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*/
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Delta_t_Utc = Delta_tLS_6 + A0_6 + A1_6 * (t_e - t0t_6 + 604800 * static_cast<double>((WN % 256) - WNot_6));
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t_Utc_daytime = fmod(t_e - Delta_t_Utc, 86400);
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}
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else
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{
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/* 5.1.7b GST->UTC case b
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* Whenever the user's current time falls within the time span of six hours
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* prior to the leap second adjustment to six hours after the adjustment time,
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* the effective time is computed according to the following equations:
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*/
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Delta_t_Utc = Delta_tLS_6 + A0_6 + A1_6 * (t_e - t0t_6 + 604800 * static_cast<double>((WN % 256) - WNot_6));
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const double W = fmod(t_e - Delta_t_Utc - 43200, 86400) + 43200;
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t_Utc_daytime = fmod(W, 86400 + Delta_tLSF_6 - Delta_tLS_6);
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// implement something to handle a leap second event!
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}
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}
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else // the effectivity time is in the past
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{
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/* 5.1.7c GST->UTC case c
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* Whenever the leap second adjustment time, as indicated by the WN_LSF and DN values,
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* is in the past (relative to the user's current time) and the user's present time does not
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* fall in the time span which starts six hours prior to the leap second adjustment time and
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* ends six hours after the adjustment time, the effective time is computed according to
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* the following equation:
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*/
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Delta_t_Utc = Delta_tLSF_6 + A0_6 + A1_6 * (t_e - t0t_6 + 604800 * static_cast<double>((WN % 256) - WNot_6));
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t_Utc_daytime = fmod(t_e - Delta_t_Utc, 86400);
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}
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const double secondsOfWeekBeforeToday = 86400 * floor(t_e / 86400);
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t_Utc = secondsOfWeekBeforeToday + t_Utc_daytime;
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return t_Utc;
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}
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