agi.foundation.communications.signalpropagation

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

Class RainAttenuationModelItuRP838Version3

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.communications.signalpropagation.SignalPropagationModel

agi.foundation.communications.signalpropagation.RainAttenuationModelItuRP838Version3

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

public class RainAttenuationModelItuRP838Version3
extends SignalPropagationModel

ITU-R P.838 version 3 rain attenuation model. This model uses the ITU-R P.838 rain attenuation model to compute the specific attenuation (dB/km) for the propagated signal due to rain, then determines the total attenuation by multiplying by the path length of the link.

The atmospheric conditions can be configured in two different ways. When using RainHeight (get / set) and RainRate (get / set), the link is divided into two sub-segments: the portion below the rain height, where the given rain rate applies, and the portion above the rain height, where no rain exists. This geometric arrangement is simple to configure, but is best suited to geometries where the link is primarily vertical.

Alternatively, configure CustomLinkSubdivision (get / set), which determines how the link should be subdivided, and CustomAtmosphericModel (get / set), which determines the rain rate at the midpoint of each sub-segment. Sub-segments can be regularly or irregularly spaced. The rain rate is assumed constant over each sub-segment. This configuration is more complex, but can represent geometries where the link is primarily horizontal and the signal might pass through multiple distinct weather cells.

The tau angle, which is defined as the polarization tilt angle relative to the horizontal, is computed using the transmitted signal's polarization axes and is measured using the surface normal computed at the grazing location of the propagation link. If the transmitted signal does not contain a Polarization instance, the value returned by the DefaultTauAngle (get / set) property is used as the tau angle. If the transmitted signal contains an instance of LeftHandCircularPolarization or RightHandCircularPolarization, the tau angle defaults to 45 degrees per the P.838 recommendation.

Constructor Summary

Constructors

Modifier	Constructor and Description
	RainAttenuationModelItuRP838Version3() Constructs version 3 of the ITU-R P.838 model
protected	RainAttenuationModelItuRP838Version3(RainAttenuationModelItuRP838Version3 existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(RainAttenuationModelItuRP838Version3 other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(SignalPropagationModel 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 model's central body.
ItuRP838AtmosphericModel	getCustomAtmosphericModel() Gets or sets a custom atmospheric model to use when computing attenuation.
LinkSubdivision	getCustomLinkSubdivision() Gets or sets a custom object which will be used to subdivide the link into sub-segments, which will then define the sample locations where the CustomAtmosphericModel (get / set) will be asked to obtain atmospheric data.
double	getDefaultTauAngle() Gets the default tau angle.
ScalarDependentOnServiceProvider	getRainHeight() Gets or sets a value for the rain height, in meters.
ScalarDependentOnServiceProvider	getRainRate() Gets or sets a custom value for the rain rate, in m/s.
SignalPropagator	getSignalPropagator(EvaluatorGroup group, IServiceProvider link) Get a propagator which can propagate a set of input signals.
void	setCustomAtmosphericModel(ItuRP838AtmosphericModel value) Gets or sets a custom atmospheric model to use when computing attenuation.
void	setCustomLinkSubdivision(LinkSubdivision value) Gets or sets a custom object which will be used to subdivide the link into sub-segments, which will then define the sample locations where the CustomAtmosphericModel (get / set) will be asked to obtain atmospheric data.
void	setDefaultTauAngle(double value) Sets the default tau angle.
void	setRainHeight(ScalarDependentOnServiceProvider value) Gets or sets a value for the rain height, in meters.
void	setRainRate(ScalarDependentOnServiceProvider value) Gets or sets a custom value for the rain rate, in m/s.

Methods inherited from class agi.foundation.communications.signalpropagation.SignalPropagationModel

checkForSameDefinition

Methods inherited from class agi.foundation.infrastructure.DefinitionalObject

areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, dictionaryItemsAreSameDefinition, freeze, freezeAggregatedObjects, 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

RainAttenuationModelItuRP838Version3

public RainAttenuationModelItuRP838Version3()

Constructs version 3 of the ITU-R P.838 model

RainAttenuationModelItuRP838Version3

protected RainAttenuationModelItuRP838Version3(@Nonnull
                                               RainAttenuationModelItuRP838Version3 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(SignalPropagationModel 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 SignalPropagationModel

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(RainAttenuationModelItuRP838Version3 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 RainAttenuationModelItuRP838Version3.checkForSameDefinition(agi.foundation.communications.signalpropagation.SignalPropagationModel) method.

Overrides:

computeCurrentDefinitionHashCode in class SignalPropagationModel

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 DefinitionalObject

Parameters:

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

getCentralBody

@Nonnull
public final CentralBody getCentralBody()

Gets the model's central body.

This property will always return the Earth CentralBody (get) returned from the CentralBodiesFacet.getFromContext() method and can not be overridden. The ITU-R P.838 model is a model of the Earth's atmosphere.

getCustomLinkSubdivision

public final LinkSubdivision getCustomLinkSubdivision()

Gets or sets a custom object which will be used to subdivide the link into sub-segments, which will then define the sample locations where the CustomAtmosphericModel (get / set) will be asked to obtain atmospheric data. Atmospheric conditions are assumed constant over each sub-segment.

Note that this property is mutually exclusive with RainHeight (get / set) and configuring this property will replace any configured RainHeight (get / set) value.

setCustomLinkSubdivision

public final void setCustomLinkSubdivision(LinkSubdivision value)

Gets or sets a custom object which will be used to subdivide the link into sub-segments, which will then define the sample locations where the CustomAtmosphericModel (get / set) will be asked to obtain atmospheric data. Atmospheric conditions are assumed constant over each sub-segment.

Note that this property is mutually exclusive with RainHeight (get / set) and configuring this property will replace any configured RainHeight (get / set) value.

getRainHeight

public final ScalarDependentOnServiceProvider getRainHeight()

Gets or sets a value for the rain height, in meters. This scalar will be provided with a service provider providing ILinkService.

Note that this property is mutually exclusive with CustomLinkSubdivision (get / set), and this property cannot be used if a CustomLinkSubdivision (get / set) is configured.

During evaluation, a PropertyInvalidException is thrown if the rain height is less than zero or greater than 20,000 meters.

Throws:

IllegalStateException - Thrown when a CustomLinkSubdivision (get / set) has been configured.

setRainHeight

public final void setRainHeight(ScalarDependentOnServiceProvider value)

Gets or sets a value for the rain height, in meters. This scalar will be provided with a service provider providing ILinkService.

Note that this property is mutually exclusive with CustomLinkSubdivision (get / set), and this property cannot be used if a CustomLinkSubdivision (get / set) is configured.

During evaluation, a PropertyInvalidException is thrown if the rain height is less than zero or greater than 20,000 meters.

Throws:

IllegalStateException - Thrown when a CustomLinkSubdivision (get / set) has been configured.

getCustomAtmosphericModel

public final ItuRP838AtmosphericModel getCustomAtmosphericModel()

Gets or sets a custom atmospheric model to use when computing attenuation.

Note that this property is mutually exclusive with RainRate (get / set) and configuring this property will replace any configured RainRate (get / set) value.

During evaluation, a PropertyInvalidException is thrown if the rain rate is less than zero or greater than 6.944e-5 m/s.

setCustomAtmosphericModel

public final void setCustomAtmosphericModel(ItuRP838AtmosphericModel value)

Gets or sets a custom atmospheric model to use when computing attenuation.

Note that this property is mutually exclusive with RainRate (get / set) and configuring this property will replace any configured RainRate (get / set) value.

During evaluation, a PropertyInvalidException is thrown if the rain rate is less than zero or greater than 6.944e-5 m/s.

getRainRate

public final ScalarDependentOnServiceProvider getRainRate()

Gets or sets a custom value for the rain rate, in m/s. This scalar will be provided with a service provider providing ILinkService.

Note that this property is mutually exclusive with CustomAtmosphericModel (get / set), and this property cannot be used if a CustomAtmosphericModel (get / set) is configured.

During evaluation, a PropertyInvalidException is thrown if the rain rate is less than zero or greater than 6.944e-5 m/s.

Throws:

IllegalStateException - Thrown when a CustomAtmosphericModel (get / set) has been configured.

setRainRate

public final void setRainRate(ScalarDependentOnServiceProvider value)

Gets or sets a custom value for the rain rate, in m/s. This scalar will be provided with a service provider providing ILinkService.

Note that this property is mutually exclusive with CustomAtmosphericModel (get / set), and this property cannot be used if a CustomAtmosphericModel (get / set) is configured.

During evaluation, a PropertyInvalidException is thrown if the rain rate is less than zero or greater than 6.944e-5 m/s.

Throws:

IllegalStateException - Thrown when a CustomAtmosphericModel (get / set) has been configured.

getDefaultTauAngle

public final double getDefaultTauAngle()

Gets the default tau angle. This is the value used in case the transmitted signal is not polarized.

setDefaultTauAngle

public final void setDefaultTauAngle(double value)

Sets the default tau angle. This is the value used in case the transmitted signal is not polarized.

getSignalPropagator

public SignalPropagator getSignalPropagator(EvaluatorGroup group,
                                            IServiceProvider link)

Get a propagator which can propagate a set of input signals.

Specified by:

getSignalPropagator in class SignalPropagationModel

Parameters:

group - The evaluator group in which to create the evaluator.

link - The link over which to propagate the signals.

Returns:

The evaluator producing the set of signals after propagation.

Throws:

ArgumentNullException - Thrown when group or link is null.

IllegalStateException - Thrown when neither CustomAtmosphericModel (get / set) nor RainRate (get / set) are configured, or when neither CustomLinkSubdivision (get / set) nor RainHeight (get / set) are configured.

ServiceNotAvailableException - Thrown when link does not provide ILinkService, or when the link transmitter does not provide ILocationPointService or IOrientationAxesService, or when the link receiver does not provide ILocationPointService, or when CustomLinkSubdivision (get / set) does not provide ILinkSubdivisionService.