Package org.orekit.frames

Class HelmertTransformation

java.lang.Object

org.orekit.frames.HelmertTransformation

All Implemented Interfaces:

TransformProvider

public class HelmertTransformation
extends Object
implements TransformProvider

Transformation class for geodetic systems.

The Helmert transformation is mainly used to convert between various realizations of geodetic frames, for example in the ITRF family.

The original Helmert transformation is a 14 parameters transform that includes translation, velocity, rotation, rotation rate and scale factor. The scale factor is useful for coordinates near Earth surface, but it cannot be extended to outer space as it would correspond to a non-unitary transform. Therefore, the scale factor is not used here.

Instances of this class are guaranteed to be immutable.

Since:

5.1

Author:

Luc Maisonobe

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	HelmertTransformation.Predefined	Enumerate for predefined Helmert transformations.

Constructor Summary

Constructors

Constructor	Description
HelmertTransformation(AbsoluteDate epoch, double t1, double t2, double t3, double r1, double r2, double r3, double t1Dot, double t2Dot, double t3Dot, double r1Dot, double r2Dot, double r3Dot)	Build a transform from its primitive operations.

Method Summary

Modifier and Type	Method	Description
AbsoluteDate	getEpoch()	Get the reference epoch of the transform.
StaticTransform	getStaticTransform(AbsoluteDate date)	Get a transform for only rotations and translations on the specified date.
<T extends CalculusFieldElement<T>> FieldStaticTransform<T>	getStaticTransform(FieldAbsoluteDate<T> date)	Get a transform for only rotations and translations on the specified date.
Transform	getTransform(AbsoluteDate date)	Get the Transform corresponding to specified date.
<T extends CalculusFieldElement<T>> FieldTransform<T>	getTransform(FieldAbsoluteDate<T> date)	Get the FieldTransform corresponding to specified date.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.frames.TransformProvider

getKinematicTransform, getKinematicTransform

Constructor Details

HelmertTransformation

public HelmertTransformation(AbsoluteDate epoch,
 double t1,
 double t2,
 double t3,
 double r1,
 double r2,
 double r3,
 double t1Dot,
 double t2Dot,
 double t3Dot,
 double r1Dot,
 double r2Dot,
 double r3Dot)

Build a transform from its primitive operations.

Parameters:

epoch - reference epoch of the transform

t1 - translation parameter along X axis (BEWARE, this is in mm)

t2 - translation parameter along Y axis (BEWARE, this is in mm)

t3 - translation parameter along Z axis (BEWARE, this is in mm)

r1 - rotation parameter around X axis (BEWARE, this is in mas)

r2 - rotation parameter around Y axis (BEWARE, this is in mas)

r3 - rotation parameter around Z axis (BEWARE, this is in mas)

t1Dot - rate of translation parameter along X axis (BEWARE, this is in mm/y)

t2Dot - rate of translation parameter along Y axis (BEWARE, this is in mm/y)

t3Dot - rate of translation parameter along Z axis (BEWARE, this is in mm/y)

r1Dot - rate of rotation parameter around X axis (BEWARE, this is in mas/y)

r2Dot - rate of rotation parameter around Y axis (BEWARE, this is in mas/y)

r3Dot - rate of rotation parameter around Z axis (BEWARE, this is in mas/y)

Method Details

getEpoch

public AbsoluteDate getEpoch()

Get the reference epoch of the transform.

Returns:

reference epoch of the transform

getTransform

public Transform getTransform(AbsoluteDate date)

Get the Transform corresponding to specified date.

Specified by:

getTransform in interface TransformProvider

Parameters:

date - current date

Returns:

transform at specified date

getStaticTransform

public StaticTransform getStaticTransform(AbsoluteDate date)

Get a transform for only rotations and translations on the specified date.

The default implementation calls TransformProvider.getTransform(AbsoluteDate) but implementations may override it for better performance.

Specified by:

getStaticTransform in interface TransformProvider

Parameters:

date - current date.

Returns:

the static transform.

getTransform

public <T extends CalculusFieldElement<T>>
FieldTransform<T> getTransform(FieldAbsoluteDate<T> date)

Get the FieldTransform corresponding to specified date.

Specified by:

getTransform in interface TransformProvider

Type Parameters:

T - type of the field elements

Parameters:

date - current date

Returns:

transform at specified date

getStaticTransform

public <T extends CalculusFieldElement<T>>
FieldStaticTransform<T> getStaticTransform(FieldAbsoluteDate<T> date)

Get a transform for only rotations and translations on the specified date.

The default implementation returns TransformProvider.getTransform(AbsoluteDate) but implementations may override it for better performance.

Specified by:

getStaticTransform in interface TransformProvider

Type Parameters:

T - type of the elements

Parameters:

date - current date.

Returns:

the static transform.