agi.foundation.celestial

(agi.foundation.orbitpropagation-2024r3.jar)

Class NPlateSolarRadiationForce

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.celestial.ForceModel

agi.foundation.celestial.NPlateSolarRadiationForce

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

public class NPlateSolarRadiationForce
extends ForceModel

A medium-fidelity force model for solar radiation pressure on a spacecraft. The model requires that a spacecraft's attitude be specified by its BodyAxes (get / set) and that the spacecraft's body and solar panels be modeled by an NPlateModel (get / set) that contains a model for each outward facing surface of the spacecraft.

This model does not take into account the effect of plates physically blocking other plates from experiencing pressure if the blocked plates are behind them but pointing in the same direction. (This effect is sometimes called self-shadowing).

Constructor Summary

Constructors

Modifier	Constructor and Description
	NPlateSolarRadiationForce() Initializes a ForceModel describing the solar radiation pressure force on an object.
	NPlateSolarRadiationForce(NPlateModel nPlateModel, Axes bodyAxes, Point targetPoint) Initializes a ForceModel describing the solar radiation pressure force on an object.
	NPlateSolarRadiationForce(NPlateModel nPlateModel, Axes bodyAxes, ScalarOccultation occultationFactor) Initializes a ForceModel describing the solar radiation pressure force on an object.
protected	NPlateSolarRadiationForce(NPlateSolarRadiationForce existingInstance, CopyContext context)

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(NPlateSolarRadiationForce 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.
Axes	getBodyAxes() Gets the axes defining the orientation of the spacecraft body.
Axes	getDefinedInAxes() Gets the axes in which this force is defined.
Scalar	getLuminosity() Gets the solar luminosity used to model the solar radiation pressure.
NPlateModel	getNPlateModel() Gets a collection that models the spacecraft's body as a collection of individual plates with oriented surface areas, specular reflectivity coefficients, and diffuse reflectivity coefficients.
ScalarOccultation	getOccultationFactor() Gets the scalar modeling the amount of occultation at the location of the TargetPoint (get / set).
Point	getTargetPoint() Gets the point at which the solar radiation is applied from the TargetPoint (get / set) of the OccultationFactor (get / set).
RadiationVectorType	getVectorType() Gets the RadiationVectorType from the VectorType (get / set) of the OccultationFactor (get / set).
void	setBodyAxes(Axes value) Sets the axes defining the orientation of the spacecraft body.
void	setLuminosity(Scalar value) Sets the solar luminosity used to model the solar radiation pressure.
void	setNPlateModel(NPlateModel value) Sets a collection that models the spacecraft's body as a collection of individual plates with oriented surface areas, specular reflectivity coefficients, and diffuse reflectivity coefficients.
void	setOccultationFactor(ScalarOccultation value) Sets the scalar modeling the amount of occultation at the location of the TargetPoint (get / set).

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

NPlateSolarRadiationForce

public NPlateSolarRadiationForce()

Initializes a ForceModel describing the solar radiation pressure force on an object.

The Luminosity (get / set) property is set with a default value of Constants.SolarLuminosity2015IauResolutionB3.

The NPlateModel (get / set), BodyAxes (get / set), and OccultationFactor (get / set) properties must be set before creating an evaluator.

NPlateSolarRadiationForce

public NPlateSolarRadiationForce(NPlateModel nPlateModel,
                                 Axes bodyAxes,
                                 Point targetPoint)

Initializes a ForceModel describing the solar radiation pressure force on an object.

Parameters:

nPlateModel - A collection that models the spacecraft's body as individual plates with oriented surface areas, specular reflectivity coefficients, and diffuse reflectivity coefficients.

bodyAxes - The axes defining the orientation of the spacecraft body.

targetPoint - The target point used to define the geometry required for the ScalarOccultation, including the SunCentralBody as the illuminating body and the EarthCentralBody and MoonCentralBody as occluding bodies.

NPlateSolarRadiationForce

public NPlateSolarRadiationForce(NPlateModel nPlateModel,
                                 Axes bodyAxes,
                                 ScalarOccultation occultationFactor)

Initializes a ForceModel describing the solar radiation pressure force on an object.

Parameters:

nPlateModel - A collection that models the spacecraft's body as individual plates with oriented surface areas, specular reflectivity coefficients, and diffuse reflectivity coefficients.

bodyAxes - The axes defining the orientation of the spacecraft body.

occultationFactor - The ScalarOccultation that models the occultation of the sun.

NPlateSolarRadiationForce

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

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(NPlateSolarRadiationForce 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 NPlateSolarRadiationForce.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.

getOccultationFactor

public final ScalarOccultation getOccultationFactor()

Gets the scalar modeling the amount of occultation at the location of the TargetPoint (get / set).

setOccultationFactor

public final void setOccultationFactor(ScalarOccultation value)

Sets the scalar modeling the amount of occultation at the location of the TargetPoint (get / set).

getTargetPoint

@Nullable
public final Point getTargetPoint()

Gets the point at which the solar radiation is applied from the TargetPoint (get / set) of the OccultationFactor (get / set). If the OccultationFactor (get / set) property is null, then this property will also return null.

getDefinedInAxes

@Nullable
public final Axes getDefinedInAxes()

Gets the axes in which this force is defined. For solar radiation, the axes are taken from the inertial frame of the IlluminatingBody (get / set) on the OccultationFactor (get / set). If the OccultationFactor (get / set) property is null, then this property will also return null.

getNPlateModel

public final NPlateModel getNPlateModel()

Gets a collection that models the spacecraft's body as a collection of individual plates with oriented surface areas, specular reflectivity coefficients, and diffuse reflectivity coefficients. All plates in this collection must be SolarRadiationPlates.

setNPlateModel

public final void setNPlateModel(NPlateModel value)

Sets a collection that models the spacecraft's body as a collection of individual plates with oriented surface areas, specular reflectivity coefficients, and diffuse reflectivity coefficients. All plates in this collection must be SolarRadiationPlates.

getBodyAxes

public final Axes getBodyAxes()

Gets the axes defining the orientation of the spacecraft body.

setBodyAxes

public final void setBodyAxes(Axes value)

Sets the axes defining the orientation of the spacecraft body.

getLuminosity

public final Scalar getLuminosity()

Gets the solar luminosity used to model the solar radiation pressure. By default, this is set to Constants.SolarLuminosity2015IauResolutionB3.

setLuminosity

public final void setLuminosity(Scalar value)

Sets the solar luminosity used to model the solar radiation pressure. By default, this is set to Constants.SolarLuminosity2015IauResolutionB3.

getVectorType

@Nonnull
public final RadiationVectorType getVectorType()

Gets the RadiationVectorType from the VectorType (get / set) of the OccultationFactor (get / set). If the OccultationFactor (get / set) property is null, then this property will return RadiationVectorType.CORRECT_FOR_LIGHT_TIME_DELAY_AND_ABERRATION.

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:

PropertyInvalidException - Thrown when Luminosity (get / set), OccultationFactor (get / set), or BodyAxes (get / set) is null. Also, thrown if NPlateModel (get / set) is null, empty, or contains plates that are not SolarRadiationPlates.