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:

// ------------------------------------------------------------------------
//
//                           JAVA Example Program.
//                           OBT OPERATIONS
//
// ------------------------------------------------------------------------

import EECFI.*;

import java.util.Vector;
import java.lang.String;
import java.lang.Long;

// Main program
public class Example
{
  public static void main(String[] args)
  {
    //-------------------------------------------------
    // 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]
      long[] obt0 = new long[]{0x00001001, 0x00011111};
      long period0 = (long)Math.floor((1/256.0)*1.0E12); // [picoseconds]
      
      EnvisatObt enviOBT = new EnvisatObt(time0, obt0, period0);
      
      enviOBT.obt[0]  = 0xFFFF0FFF;
      enviOBT.obt[1]  = 0x000FF000;
      
      Time timeFromOBT = enviOBT.getTime();
      
      System.out.println( "Input Time:"   );
      System.out.println( "   time0 = "   + enviOBT.time0   );
      System.out.println( "   obt0[0] = " + enviOBT.obt0[0] );
      System.out.println( "   obt0[1] = " + enviOBT.obt0[1] );
      System.out.println( "   period0 = " + enviOBT.period0 );
      System.out.println( "   obt[0] = "  + enviOBT.obt[0]  );
      System.out.println( "   obt[1] = "  + enviOBT.obt[1]  );
      
      System.out.println( "Output Time:"  );
      System.out.println( "   time = "    + timeFromOBT.time 
      + "Ref = " + timeFromOBT.ref );
      
      
      // Time to Envisat OBT time
      
      timeFromOBT.time = 245.120493735624819;
      
      EnvisatObt newEnviOBT = new EnvisatObt(time0, obt0, period0);
      
      newEnviOBT.setObt(timeFromOBT);
      
      System.out.println( "Input Time:"   );
      System.out.println( "   time = "    + timeFromOBT.time 
      + "Ref = " + timeFromOBT.ref );
      
      System.out.println( "Output Time:"  );
      System.out.println( "   time0 = "   + newEnviOBT.time0   );
      System.out.println( "   obt0[0] = " + newEnviOBT.obt0[0] );
      System.out.println( "   obt0[1] = " + newEnviOBT.obt0[1] );
      System.out.println( "   period0 = " + newEnviOBT.period0 );
      System.out.println( "   obt[0] = "  + newEnviOBT.obt[0]  );
      System.out.println( "   obt[1] = "  + newEnviOBT.obt[1]  );
      
      
    }//end try
    
    catch (CfiError cfiError)
    {
      //If an exception is thrown, there have been errors during execution
      Vector<String> errorMessages = new Vector<String>();
      
      // Get error messages
      errorMessages = cfiError.getMsg(errorMessages);
      
      // Pring Error messages
      for (int i = 0; i < errorMessages.size(); i++)
      {
        System.out.println( errorMessages.elementAt(i) );
      }
    }
    
  }
  
}