EphTime.hpp

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//==============================================================================
//
//  This file is part of GNSSTk, the ARL:UT GNSS Toolkit.
//
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//  This software was developed by Applied Research Laboratories at the
//  University of Texas at Austin.
//  Copyright 2004-2022, The Board of Regents of The University of Texas System
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//==============================================================================
 
//==============================================================================
//
//  This software was developed by Applied Research Laboratories at the
//  University of Texas at Austin, under contract to an agency or agencies
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//  rights to use, duplicate, distribute, disclose, or release this software.
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//  Pursuant to DoD Directive 523024
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//  DISTRIBUTION STATEMENT A: This software has been approved for public
//                            release, distribution is unlimited.
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//==============================================================================
 
#ifndef GEOMATICS_EPHTIME_HPP
#define GEOMATICS_EPHTIME_HPP
 
#include "Exception.hpp"
#include "TimeSystem.hpp"
 
#include "CivilTime.hpp"
#include "CommonTime.hpp"
#include "MJD.hpp"
#include "TimeConverters.hpp"
 
namespace gnsstk
{
 
 
 
   class EphTime
   {
   private:
      long iMJD;         
      double dSOD;       
      TimeSystem system; 
 
   public:
      EphTime() : iMJD(0), dSOD(0.0), system(TimeSystem::Unknown) {}
 
      EphTime(int imjd, double dsod, TimeSystem sys = TimeSystem::UTC)
         : iMJD(imjd), dSOD(dsod), system(sys)
      {
      }
 
      EphTime(double mjd, TimeSystem sys = TimeSystem::UTC) : system(sys)
      {
         setMJD(mjd);
         setTimeSystem(sys);
      }
 
      void convertSystemTo(const TimeSystem& ts)
      {
         try
         {
            long jday(static_cast<long>(iMJD + dSOD / SEC_PER_DAY + MJD_JDAY));
            int yy, mm, dd;
            convertJDtoCalendar(jday, yy, mm, dd);
            double dt, days = dd + dSOD / SEC_PER_DAY;
            // correct time
            dt = gnsstk::getTimeSystemCorrection(system, ts, yy, mm, days);
            *this += dt;
            // set new system
            this->setTimeSystem(ts);
         }
         catch (Exception& e)
         {
            GNSSTK_RETHROW(e);
         }
      }
 
      EphTime& operator+=(double seconds)
      {
         dSOD += seconds;
         while (dSOD >= 86400.0)
         {
            dSOD -= 86400.0;
            iMJD++;
         }
         while (dSOD < 0.0)
         {
            dSOD += 86400.0;
            iMJD--;
         }
         return *this;
      }
 
      void setTimeSystem(TimeSystem sys)
      {
         if (sys != TimeSystem::UTC && sys != TimeSystem::TT &&
             sys != TimeSystem::TDB)
         {
            GNSSTK_THROW(Exception("Time system not allowed"));
         }
         system = sys;
      }
 
      void setMJD(long double mjd)
      {
         iMJD = long(mjd);
         dSOD = (mjd - static_cast<double>(iMJD)) * 86400.0;
      }
 
      long lMJD() const { return iMJD; }
 
      double dMJD() const
      {
         return (static_cast<double>(iMJD) + dSOD / 86400.);
      }
 
      double secOfDay() const { return dSOD; }
 
      int year() const
      {
         long jday(static_cast<long>(iMJD + dSOD / SEC_PER_DAY + MJD_JDAY));
         int yy, mm, dd;
         convertJDtoCalendar(jday, yy, mm, dd);
         return yy;
      }
 
      EphTime(const CommonTime& dt)
      {
         try
         {
            CommonTime ct(dt);
            TimeSystem sys = ct.getTimeSystem();
            if (sys == TimeSystem::Unknown || sys == TimeSystem::Any)
            {
               ct.setTimeSystem(TimeSystem::UTC);
            }
            // if its not UTC TT or TDB, convert it to UTC
            else if (sys != TimeSystem::UTC && sys != TimeSystem::TT &&
                     sys != TimeSystem::TDB)
            {
               CivilTime civt;
               civt.convertFromCommonTime(ct);
               double dt = gnsstk::getTimeSystemCorrection(
                  sys, TimeSystem::UTC, civt.year, civt.month, civt.day);
               ct += dt;
            }
 
            MJD ctmjd;
            ctmjd.convertFromCommonTime(ct);
            iMJD   = static_cast<long>(ctmjd.mjd);
            dSOD   = (ctmjd.mjd - static_cast<long double>(iMJD)) * SEC_PER_DAY;
            system = ctmjd.getTimeSystem();
         }
         catch (Exception& e)
         {
            GNSSTK_RETHROW(e);
         }
      }
 
      operator CommonTime() const
      {
         MJD ctmjd;
         ctmjd.mjd     = static_cast<long double>(iMJD + dSOD / SEC_PER_DAY);
         CommonTime ct = ctmjd.convertToCommonTime();
         ct.setTimeSystem(system);
         return ct;
      }
 
      // no this is not a duplicate of the previous function
      operator CommonTime()
      {
         MJD ctmjd;
         ctmjd.mjd     = static_cast<long double>(iMJD + dSOD / SEC_PER_DAY);
         CommonTime ct = ctmjd.convertToCommonTime();
         ct.setTimeSystem(system);
         return ct;
      }
 
      std::string asGPSString(const int prec = 2) const
      {
         std::ostringstream oss;
         int wk((iMJD - GPS_EPOCH_MJD) / 7);
         double sow((iMJD - wk * 7) * SEC_PER_DAY + dSOD);
         if (sow >= FULLWEEK)
         {
            sow -= FULLWEEK;
            wk++;
         }
         oss << wk << " " << std::fixed << std::setprecision(prec) << sow;
         return oss.str();
      }
 
      std::string asMJDString(const int prec = 3) const
      {
         std::ostringstream oss;
         int hh, mm;
         double sec;
         convertSODtoTime(dSOD, hh, mm, sec);
         oss << iMJD << " " << std::setfill('0') << std::setw(2) << hh << ":"
             << std::setw(2) << mm << ":" << std::setfill(' ') << std::fixed
             << std::setprecision(prec) << sec;
         return oss.str();
      }
 
   }; // end class EphTime
 
 
} // namespace gnsstk
 
#endif // GEOMATICS_EPHTIME_HPP