mirror of https://github.com/gnss-sdr/gnss-sdr
115 lines
4.8 KiB
C++
115 lines
4.8 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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* Copyright (C) 2010-2013 (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 "galileo_utc_model.h"
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Galileo_Utc_Model::Galileo_Utc_Model()
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{
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//valid = false;
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/*Word type 6: GST-UTC conversion parameters*/
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A0_6 = 0;
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A1_6 = 0;
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Delta_tLS_6 = 0;
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t0t_6 = 0;
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WNot_6 = 0;
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WN_LSF_6 = 0;
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DN_6 = 0;
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Delta_tLSF_6 = 0;
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flag_utc_model = false;
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}
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double Galileo_Utc_Model::GST_to_UTC_time(double t_e, int WN)
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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 = Delta_tLS_6 + A0_6 + A1_6 * (t_e - t0t_6 + 604800 * (double)(WN - WNot_6));
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// Determine if the effectivity time of the leap second event is in the past
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int weeksToLeapSecondEvent = WN_LSF_6 - WN;
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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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int secondOfLeapSecondEvent = DN_6 * 24 * 60 * 60;
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if (weeksToLeapSecondEvent > 0)
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{
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t_Utc_daytime = fmod(t_e - Delta_t_Utc, 86400);
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}
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else //we are in the same week than the leap second event
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{
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if (abs(t_e - secondOfLeapSecondEvent) > 21600)
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{
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/* 5.1.7a
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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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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
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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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int 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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if ( (t_e - secondOfLeapSecondEvent) > 21600)
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{
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Delta_t_Utc = Delta_tLSF_6 + A0_6 + A1_6 * (t_e - t0t_6 + 604800*(double)(WN - WNot_6));
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t_Utc_daytime = fmod(t_e - Delta_t_Utc, 86400);
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}
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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
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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 * (double)(WN - WNot_6));
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t_Utc_daytime = fmod(t_e - Delta_t_Utc, 86400);
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}
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double secondsOfWeekBeforeToday = 43200 * floor(t_e / 43200);
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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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