ON BOARD TIMES CALCULATION

The following classes allow to convert On Board Time to MJD2000 time and vice versa:

• AeolusOBT
• GoceOBT
• EnvisatOBT
• SmosOBT

The following example shows how to make this transformations in the case of Envisat OBT:

// ------------------------------------------------------------------------
//
//                           C++ Example Program.
//                           OBT OPERATIONS
//
// ------------------------------------------------------------------------

// Non-EOCFI include files
#include <string>
#include <vector>
#include <iostream>

// EOCFI includes
#include "CfiError.h"
#include "LibData.h"
#include "EETime.h"
#include "EnvisatObt.h"

// Namespaces
using namespace EECFI;
using namespace std;

// Main program
int main (int argc, char *argv[])
{
  //-------------------------------------------------
  // Put all the code inside try-catch statements
  //  so, if something fails, an exception is thrown
  //-------------------------------------------------

  try
  {
   // ------------------------------------------------------------------------
   // OBT Time transformations
   // ------------------------------------------------------------------------ 

   // Envisat OBT to time
   double        time0   = 245.123456789000000;   // [days]
   unsigned long obt0[2] = {0x00001001, 0x00011111};
   unsigned long period0 = (unsigned long) ((1/256.0)*1.0E12); // [picoseconds]

   EnvisatObt enviOBT(time0, obt0, period0);

   enviOBT.obt[0]  = 0xFFFF0FFF;
   enviOBT.obt[1]  = 0x000FF000;

   Time timeFromOBT = enviOBT.getTime();
   
   cout << "Input Time:"   << endl;
   cout << "   time0 = "   << enviOBT.time0   << endl;
   cout << "   obt0[0] = " << enviOBT.obt0[0] << endl;
   cout << "   obt0[1] = " << enviOBT.obt0[1] << endl;
   cout << "   period0 = " << enviOBT.period0 << endl;
   cout << "   obt[0] = "  << enviOBT.obt[0]  << endl;
   cout << "   obt[1] = "  << enviOBT.obt[1]  << endl;

   cout << "Output Time:"  << endl;
   cout << "   time = "    << timeFromOBT.time 
        << "Ref = " << timeFromOBT.ref << endl << endl;


   // Time to Envisat OBT time

   timeFromOBT.time = 245.120493735624819;

   EnvisatObt newEnviOBT(time0, obt0, period0);

   newEnviOBT.setObt(timeFromOBT);

   cout << "Input Time:"   << endl;
   cout << "   time = "    << timeFromOBT.time 
        << "Ref = " << timeFromOBT.ref << endl;

   cout << "Output Time:"  << endl;
   cout << "   time0 = "   << newEnviOBT.time0   << endl;
   cout << "   obt0[0] = " << newEnviOBT.obt0[0] << endl;
   cout << "   obt0[1] = " << newEnviOBT.obt0[1] << endl;
   cout << "   period0 = " << newEnviOBT.period0 << endl;
   cout << "   obt[0] = "  << newEnviOBT.obt[0]  << endl;
   cout << "   obt[1] = "  << newEnviOBT.obt[1]  << endl << endl;


  }//end try

  catch (CfiError cfiError)
  {
    //If an exception is thrown, there have been errors during execution
    vector<string> errorMessages;
    
    // Get error messages
    cfiError.getMsg(errorMessages);

    // Pring Error messages
    for (long i = 0; i < errorMessages.size(); i++)
    {
      cout << errorMessages[i] << endl;
    }
  }

  return 0;

}