agi.foundation.celestial

(agi.foundation.orbitpropagation-2024r2.jar)

Class IersTechnicalNote36RelativisticCorrectionForce

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.celestial.ForceModel

agi.foundation.celestial.IersTechnicalNote36RelativisticCorrectionForce

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

public class IersTechnicalNote36RelativisticCorrectionForce
extends ForceModel

A KindOfForce.NEWTONIAN_SPECIFIC_FORCE that models the first order correction to the acceleration of a space object about a CentralBody (get / set). The mathematical details for this model may be found in chapter 10 of "IERS Conventions (2010)". The model was primarily designed for artificial satellites about Earth, but may be used with any space object and any CentralBody (get / set) in the solar system. The force always returns the primary contributor to the correction, the Schwarzchild field of the central body. By default, corrections for frame-dragging and precession of the geodesic are also included, but may be turned off if so desired.

Constructor Summary

Constructors

Modifier	Constructor and Description
	IersTechnicalNote36RelativisticCorrectionForce() Initializes a new instance.
	IersTechnicalNote36RelativisticCorrectionForce(CentralBody centralBody, double centralBodyGravitationalParameter, double solarGravitationalParameter) Initializes the correction force with the specified CentralBody (get / set), solar gravitational parameter, and central body gravitational parameter.
protected	IersTechnicalNote36RelativisticCorrectionForce(IersTechnicalNote36RelativisticCorrectionForce existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.
	IersTechnicalNote36RelativisticCorrectionForce(Point targetPoint) Initializes the correction force with the specified Point.
	IersTechnicalNote36RelativisticCorrectionForce(Point targetPoint, CentralBody centralBody, CentralBody solarCentralBody, Vector centralBodyAngularMomentumPerUnitMass, double centralBodyGravitationalParameter, double solarGravitationalParameter, boolean useLenseThirringCorrection, boolean useDeSitterCorrection) Initializes the correction force with the specified parameters.

Method Summary

Modifier and Type	Method and Description
void	buildForceEvaluator(ResultantForceBuilder builder, EvaluatorGroup group) Build lists of principal and perturbation forces based on this model in order to create an overall resultant force.
protected boolean	checkForSameDefinition(ForceModel other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(IersTechnicalNote36RelativisticCorrectionForce other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
Object	clone(CopyContext context) Clones this object using the specified context.
protected int	computeCurrentDefinitionHashCode() Computes a hash code based on the current properties of this object.
void	enumerateDependencies(DependencyEnumerator enumerator) Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon.
CentralBody	getCentralBody() Gets the CentralBody about which this correction is applied.
Vector	getCentralBodyAngularMomentumPerUnitMass() Gets a vector that describes the angular momentum per unit mass of the CentralBody (get / set).
double	getCentralBodyGravitationalParameter() Gets the gravitational parameter for the CentralBody (get / set).
CentralBody	getSolarCentralBody() Gets the CentralBody that represents the sun of the solar system where this force is used.
double	getSolarGravitationalParameter() Gets the gravitational parameter for the Sun.
Point	getTargetPoint() Gets the point at which the IersTechnicalNote36RelativisticCorrectionForce is applied.
boolean	getUseDeSitterCorrection() Gets a value indicating whether the de Sitter correction is to be used.
boolean	getUseLenseThirringCorrection() Gets a value indicating whether the Lense-Thirring correction is to be used.
static Vector	routhsRuleAngularMomentumPerUnitMass(CentralBody centralBody) A static helper method that computes a CentralBodyAngularMomentumPerUnitMass (get / set) vector for the input centralBody.
static Vector	scaledAngularVelocityAngularMomentumPerUnitMass(CentralBody centralBody, double scale) A static helper method that computes a CentralBodyAngularMomentumPerUnitMass (get / set) vector for the input centralBody.
void	setCentralBody(CentralBody value) Sets the CentralBody about which this correction is applied.
void	setCentralBodyAngularMomentumPerUnitMass(Vector value) Sets a vector that describes the angular momentum per unit mass of the CentralBody (get / set).
void	setCentralBodyGravitationalParameter(double value) Sets the gravitational parameter for the CentralBody (get / set).
void	setSolarCentralBody(CentralBody value) Sets the CentralBody that represents the sun of the solar system where this force is used.
void	setSolarGravitationalParameter(double value) Sets the gravitational parameter for the Sun.
void	setTargetPoint(Point value) Sets the point at which the IersTechnicalNote36RelativisticCorrectionForce is applied.
void	setUseDeSitterCorrection(boolean value) Sets a value indicating whether the de Sitter correction is to be used.
void	setUseLenseThirringCorrection(boolean value) Sets a value indicating whether the Lense-Thirring correction is to be used.

Methods inherited from class agi.foundation.celestial.ForceModel

checkForSameDefinition, freezeAggregatedObjects, getForceEvaluator, getForceEvaluator, getForceVector, getKind, getRole

Methods inherited from class agi.foundation.infrastructure.DefinitionalObject

areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, dictionaryItemsAreSameDefinition, freeze, getCollectionHashCode, getCollectionHashCode, getCollectionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDictionaryHashCode, getIsFrozen, isSameDefinition, throwIfFrozen

Methods inherited from class java.lang.Object

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

Constructor Detail

IersTechnicalNote36RelativisticCorrectionForce

public IersTechnicalNote36RelativisticCorrectionForce(CentralBody centralBody,
                                                      double centralBodyGravitationalParameter,
                                                      double solarGravitationalParameter)

Initializes the correction force with the specified CentralBody (get / set), solar gravitational parameter, and central body gravitational parameter. The SolarCentralBody (get / set) is set to the sun from the CentralBodiesFacet. Both additional corrections (de Sitter and Lense-Thirring) will be used.

The TargetPoint (get / set) and CentralBodyAngularMomentumPerUnitMass (get / set) properties will need to be set before use.

Parameters:

centralBody - The central body to be used in the computation of this force.

centralBodyGravitationalParameter - The gravitational parameter for the central body.

solarGravitationalParameter - The gravitational parameter for the Sun.

IersTechnicalNote36RelativisticCorrectionForce

public IersTechnicalNote36RelativisticCorrectionForce(Point targetPoint)

Initializes the correction force with the specified Point. The CentralBody (get / set) is set to Earth from the CentralBodiesFacet, and the SolarCentralBody (get / set) is set to the sun from the CentralBodiesFacet. Both additional corrections (de Sitter and Lense-Thirring) will be used.

The gravitational parameters and the CentralBodyAngularMomentumPerUnitMass (get / set) properties will need to be set before use.

Parameters:

targetPoint - The point to which this correction force applies.

IersTechnicalNote36RelativisticCorrectionForce

public IersTechnicalNote36RelativisticCorrectionForce(Point targetPoint,
                                                      CentralBody centralBody,
                                                      CentralBody solarCentralBody,
                                                      Vector centralBodyAngularMomentumPerUnitMass,
                                                      double centralBodyGravitationalParameter,
                                                      double solarGravitationalParameter,
                                                      boolean useLenseThirringCorrection,
                                                      boolean useDeSitterCorrection)

Initializes the correction force with the specified parameters.

Parameters:

targetPoint - The point to which this force is applied.

centralBody - The central body about which this force is calculated.

solarCentralBody - The central body that represents the sun of the solar system where this force is used.

centralBodyAngularMomentumPerUnitMass - The vector that specifies the rotational angular momentum per unit mass of the central body.

centralBodyGravitationalParameter - The gravitational parameter for the centralBody.

solarGravitationalParameter - The gravitational parameter for the Sun.

useLenseThirringCorrection - Set to true to use the Lense-Thirring correction.

useDeSitterCorrection - Set to true to use the de Sitter correction.

IersTechnicalNote36RelativisticCorrectionForce

public IersTechnicalNote36RelativisticCorrectionForce()

Initializes a new instance.

IersTechnicalNote36RelativisticCorrectionForce

protected IersTechnicalNote36RelativisticCorrectionForce(@Nonnull
                                                         IersTechnicalNote36RelativisticCorrectionForce existingInstance,
                                                         @Nonnull
                                                         CopyContext context)

Initializes a new instance as a copy of an existing instance.

See ICloneWithContext.clone(CopyContext) for more information about how to implement this constructor in a derived class.

Parameters:

existingInstance - The existing instance to copy.

context - A CopyContext that controls the depth of the copy.

Throws:

ArgumentNullException - Thrown when existingInstance or context is null.

Method Detail

clone

public Object clone(CopyContext context)

Clones this object using the specified context.

This method should be implemented to call a copy constructor on the class of the object being cloned. The copy constructor should take the CopyContext as a parameter in addition to the existing instance to copy. The copy constructor should first call CopyContext.addObjectMapping(T, T) to identify the newly constructed instance as a copy of the existing instance. It should then copy all fields, using CopyContext.updateReference(T) to copy any reference fields.

A typical implementation of ICloneWithContext:

public static class MyClass implements ICloneWithContext {
    public MyClass(MyClass existingInstance, CopyContext context) {
        context.addObjectMapping(existingInstance, this);
        someReference = context.updateReference(existingInstance.someReference);
    }

    @Override
    public final Object clone(CopyContext context) {
        return new MyClass(this, context);
    }

    private Object someReference;
}

In general, all fields that are reference types should be copied with a call to CopyContext.updateReference(T). There are a couple of exceptions:

1. Fields that are aggregate parts of the object should always be copied. A referenced object is an aggregate if properties or methods on the object being copied can modify the externally-visible value of the referenced object.
2. If the semantics of the referenced object require that it have a single parent, owner, context, etc., and the object being copied is that parent, owner, or context, then the referenced object should always be copied.

If one of these exceptions applies, the CopyContext should be given an opportunity to update the reference before the reference is copied explicitly. Use CopyContext.updateReference(T) to update the reference. If CopyContext.updateReference(T) returns the original object, indicating that the context does not have a replacement registered, then copy the object manually by invoking a Clone method, a copy constructor, or by manually constructing a new instance and copying the values.

alwaysCopy = context.updateReference(existingInstance.alwaysCopy);
if (existingInstance.alwaysCopy != null && alwaysCopy == existingInstance.alwaysCopy) {
    alwaysCopy = (AlwaysCopy) existingInstance.alwaysCopy.clone(context);
}

If you are implementing an evaluator (a class that implements IEvaluator), the IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) method shares some responsibilities with the copy context constructor. Code duplication can be avoided by doing the following:

1. For references to other evaluators ONLY, simply assign the reference in the constructor instead of calling CopyContext.updateReference(T). You should still call CopyContext.updateReference(T) on any references to non-evaluators.
2. Call IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) as the last line in the constructor and pass it the same CopyContext passed to the constructor.
3. Implement IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) as normal. See the reference documentation for IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) for more information on implementing that method.

public MyClass(MyClass existingInstance, CopyContext context) {
    super(existingInstance, context);
    someReference = context.updateReference(existingInstance.someReference);
    evaluatorReference = existingInstance.evaluatorReference;
    updateEvaluatorReferences(context);
}

@Override
public void updateEvaluatorReferences(CopyContext context) {
    evaluatorReference = context.updateReference(evaluatorReference);
}

@Override
public Object clone(CopyContext context) {
    return new MyClass(this, context);
}

private Object someReference;
private IEvaluator evaluatorReference;

Specified by:

clone in interface ICloneWithContext

Specified by:

clone in class DefinitionalObject

Parameters:

context - The context to use to perform the copy.

Returns:

A new instance which is a copy of this object.

checkForSameDefinition

protected final boolean checkForSameDefinition(ForceModel other)

Checks to determine if another instance has the same definition as this instance and returns true if it does. Derived classes MUST override this method and check all new fields introduced by the derived class for definitional equivalence. It is NOT necessary to check base class fields because the base class will already have done that. When overriding this method, you should NOT call the base implementation because it will return false for all derived-class instances. Derived classes should check the type of other to preserve the symmetric nature of IEquatableDefinition.isSameDefinition(java.lang.Object).

Specified by:

checkForSameDefinition in class ForceModel

Parameters:

other - The other instance to compare to this one.

Returns:

true if the two objects are defined equivalently; otherwise false.

checkForSameDefinition

protected boolean checkForSameDefinition(@Nullable
                                         IersTechnicalNote36RelativisticCorrectionForce other)

Checks to determine if another instance has the same definition as this instance and returns true if it does. Derived classes MUST override this method and check all new fields introduced by the derived class for definitional equivalence. It is NOT necessary to check base class fields because the base class will already have done that. When overriding this method, you should NOT call the base implementation because it will return false for all derived-class instances. Derived classes should check the type of other to preserve the symmetric nature of IEquatableDefinition.isSameDefinition(java.lang.Object).

Parameters:

other - The other instance to compare to this one.

Returns:

true if the two objects are defined equivalently; otherwise false.

computeCurrentDefinitionHashCode

protected int computeCurrentDefinitionHashCode()

Computes a hash code based on the current properties of this object. Derived classes MUST override this method and compute a hash code that combines: a unique hash code seed, the base implementation result, and the hash codes of all new fields introduced by the derived class which are used in the IersTechnicalNote36RelativisticCorrectionForce.checkForSameDefinition(agi.foundation.celestial.ForceModel) method.

Overrides:

computeCurrentDefinitionHashCode in class ForceModel

Returns:

The computed hash code.

enumerateDependencies

public void enumerateDependencies(DependencyEnumerator enumerator)

Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon. Derived classes which contain additional dependencies MUST override this method, call the base implementation, and enumerate dependencies introduced by the derived class.

Specified by:

enumerateDependencies in interface IEnumerateDependencies

Overrides:

enumerateDependencies in class ForceModel

Parameters:

enumerator - The enumerator that is informed of the dependencies of this object.

getTargetPoint

public final Point getTargetPoint()

Gets the point at which the IersTechnicalNote36RelativisticCorrectionForce is applied.

setTargetPoint

public final void setTargetPoint(Point value)

Sets the point at which the IersTechnicalNote36RelativisticCorrectionForce is applied.

getCentralBodyGravitationalParameter

public final double getCentralBodyGravitationalParameter()

Gets the gravitational parameter for the CentralBody (get / set).

setCentralBodyGravitationalParameter

public final void setCentralBodyGravitationalParameter(double value)

Sets the gravitational parameter for the CentralBody (get / set).

getSolarGravitationalParameter

public final double getSolarGravitationalParameter()

Gets the gravitational parameter for the Sun.

setSolarGravitationalParameter

public final void setSolarGravitationalParameter(double value)

Sets the gravitational parameter for the Sun.

getCentralBody

public final CentralBody getCentralBody()

Gets the CentralBody about which this correction is applied.

setCentralBody

public final void setCentralBody(CentralBody value)

Sets the CentralBody about which this correction is applied.

getSolarCentralBody

public final CentralBody getSolarCentralBody()

Gets the CentralBody that represents the sun of the solar system where this force is used.

setSolarCentralBody

public final void setSolarCentralBody(CentralBody value)

Sets the CentralBody that represents the sun of the solar system where this force is used.

getCentralBodyAngularMomentumPerUnitMass

public final Vector getCentralBodyAngularMomentumPerUnitMass()

Gets a vector that describes the angular momentum per unit mass of the CentralBody (get / set). This vector is used for the Lense-Thirring correction, and may be safely ignored if this term is not used. Two easy-to-use static helper methods for this vector exist on this class; IersTechnicalNote36RelativisticCorrectionForce.routhsRuleAngularMomentumPerUnitMass(agi.foundation.celestial.CentralBody) and IersTechnicalNote36RelativisticCorrectionForce.scaledAngularVelocityAngularMomentumPerUnitMass(agi.foundation.celestial.CentralBody, double).

One way to get this vector easily is to use VectorAngularVelocity with the axes of the fixed frame of the central body used as the rotating axes, and the axes of the solar system barycenter's inertial frame used as the reference axes. This angular velocity vector can then be fed into a VectorScaled using Routh's rule for an ellipsoid, less the mass term, as the scale factor to obtain the desired vector.

setCentralBodyAngularMomentumPerUnitMass

public final void setCentralBodyAngularMomentumPerUnitMass(Vector value)

Sets a vector that describes the angular momentum per unit mass of the CentralBody (get / set). This vector is used for the Lense-Thirring correction, and may be safely ignored if this term is not used. Two easy-to-use static helper methods for this vector exist on this class; IersTechnicalNote36RelativisticCorrectionForce.routhsRuleAngularMomentumPerUnitMass(agi.foundation.celestial.CentralBody) and IersTechnicalNote36RelativisticCorrectionForce.scaledAngularVelocityAngularMomentumPerUnitMass(agi.foundation.celestial.CentralBody, double).

One way to get this vector easily is to use VectorAngularVelocity with the axes of the fixed frame of the central body used as the rotating axes, and the axes of the solar system barycenter's inertial frame used as the reference axes. This angular velocity vector can then be fed into a VectorScaled using Routh's rule for an ellipsoid, less the mass term, as the scale factor to obtain the desired vector.

routhsRuleAngularMomentumPerUnitMass

@Nonnull
public static Vector routhsRuleAngularMomentumPerUnitMass(@Nonnull
                                                                    CentralBody centralBody)

A static helper method that computes a CentralBodyAngularMomentumPerUnitMass (get / set) vector for the input centralBody. This method uses Routh's rule for an ellipsoid coupled with the angular velocity vector computed between the fixed and inertial frames defined on the centralBody.

Parameters:

centralBody - The central body for which to create this vector.

Returns:

A vector suitable for use with the CentralBodyAngularMomentumPerUnitMass (get / set) property.

scaledAngularVelocityAngularMomentumPerUnitMass

@Nonnull
public static Vector scaledAngularVelocityAngularMomentumPerUnitMass(@Nonnull
                                                                               CentralBody centralBody,
                                                                               double scale)

A static helper method that computes a CentralBodyAngularMomentumPerUnitMass (get / set) vector for the input centralBody. This method computes the rotational velocity between the central body's fixed and inertial frames. This vector is then normalized and the magnitude is set to the input scale factor. An appropriate scale factor for the Earth, for example, would be 9.8e8 m^2/s as was cited in "IERS Conventions (2010)".

Parameters:

centralBody - The central body for which to create this vector.

scale - A double that represents the value of the magnitude of the output vector.

Returns:

A vector suitable for use with the CentralBodyAngularMomentumPerUnitMass (get / set) property.

getUseLenseThirringCorrection

public final boolean getUseLenseThirringCorrection()

Gets a value indicating whether the Lense-Thirring correction is to be used. This defaults to true.

setUseLenseThirringCorrection

public final void setUseLenseThirringCorrection(boolean value)

Sets a value indicating whether the Lense-Thirring correction is to be used. This defaults to true.

getUseDeSitterCorrection

public final boolean getUseDeSitterCorrection()

Gets a value indicating whether the de Sitter correction is to be used. This defaults to true.

This term should not be used if the central body is set to the Sun.

setUseDeSitterCorrection

public final void setUseDeSitterCorrection(boolean value)

Sets a value indicating whether the de Sitter correction is to be used. This defaults to true.

This term should not be used if the central body is set to the Sun.

buildForceEvaluator

public void buildForceEvaluator(ResultantForceBuilder builder,
                                EvaluatorGroup group)

Build lists of principal and perturbation forces based on this model in order to create an overall resultant force.

Specified by:

buildForceEvaluator in class ForceModel

Parameters:

builder - The builder object containing the lists and additional information on the Axes in which the overall resultant is defined.

group - The evaluator group in which to create evaluators.

Throws:

ArgumentNullException - Thrown if builder or group is null.

PropertyInvalidException - Thrown if CentralBody (get / set) or TargetPoint (get / set) is null. This exception is also thrown if CentralBodyAngularMomentumPerUnitMass (get / set) is null and the Lense-Thirring correction effect is active.