org.orekit.time

Class TDBScale

java.lang.Object

org.orekit.time.TDBScale

All Implemented Interfaces:

Serializable, TimeScale

public class TDBScale
extends Object
implements TimeScale

Barycentric Dynamic Time.

Time used to take account of time dilation when calculating orbits of planets, asteroids, comets and interplanetary spacecraft in the Solar system. It was based on a Dynamical time scale but was not well defined and not rigorously correct as a relativistic time scale. It was subsequently deprecated in favour of Barycentric Coordinate Time (TCB), but at the 2006 General Assembly of the International Astronomical Union TDB was rehabilitated by making it a specific fixed linear transformation of TCB.

By convention, TDB = TT + 0.001658 sin(g) + 0.000014 sin(2g)seconds where g = 357.53 + 0.9856003 (JD - 2451545) degrees.

Author:

Aude Privat

See Also:

Serialized Form

Method Summary

Modifier and Type	Method and Description
double	getLeap(AbsoluteDate date) Get the value of the previous leap.
String	getName() Get the name time scale.
boolean	insideLeap(AbsoluteDate date) Check if date is within a leap second introduction in this time scale.
double	offsetFromTAI(AbsoluteDate date) Get the offset to convert locations from TAIScale to instance.
double	offsetToTAI(DateComponents date, TimeComponents time) Get the offset to convert locations from instance to TAIScale.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

offsetFromTAI

public double offsetFromTAI(AbsoluteDate date)

Get the offset to convert locations from TAIScale to instance.

Specified by:

offsetFromTAI in interface TimeScale

Parameters:

date - conversion date

Returns:

offset in seconds to add to a location in TAIScale time scale to get a location in instance time scale

See Also:

TimeScale.offsetToTAI(DateComponents, TimeComponents)

offsetToTAI

public double offsetToTAI(DateComponents date,
                          TimeComponents time)

Get the offset to convert locations from instance to TAIScale.

Specified by:

offsetToTAI in interface TimeScale

Parameters:

date - date location in the time scale

time - time location in the time scale

Returns:

offset in seconds to add to a location in instance time scale to get a location in TAIScale time scale

See Also:

TimeScale.offsetFromTAI(AbsoluteDate)

insideLeap

public boolean insideLeap(AbsoluteDate date)

Check if date is within a leap second introduction in this time scale.

This method will return false for all time scales that do not implement leap seconds, even if the date corresponds to a leap second in UTC scale.

Specified by:

insideLeap in interface TimeScale

Parameters:

date - date to check

Returns:

true if time is within a leap second introduction

getLeap

public double getLeap(AbsoluteDate date)

Get the value of the previous leap.

This method will return 0.0 for all time scales that do not implement leap seconds.

Specified by:

getLeap in interface TimeScale

Parameters:

date - date to check

Returns:

value of the previous leap

getName

public String getName()

Get the name time scale.

Specified by:

getName in interface TimeScale

Returns:

name of the time scale

toString

public String toString()

Overrides:

toString in class Object