agi.foundation.navigation.advanced.signalprocessing

(agi.foundation.navigation.advanced-2024r1.jar)

Class GpsPowerSpectralDensityFilter

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.communications.signalprocessing.SignalProcessor

agi.foundation.communications.signalprocessing.SignalFilter

agi.foundation.navigation.advanced.signalprocessing.GpsPowerSpectralDensityFilter

All Implemented Interfaces:

ISignalSource, ISignalOutputService, ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable, IServiceProvider

public class GpsPowerSpectralDensityFilter
extends SignalFilter

A filter which constrains the incoming signals into a specified bandwidth range, accounting for GPS power spectral density

The filter constrains the signal in the following way:

• If the input signal is inside the filter bandwidth: the output signal noise bandwidth will be constrained to only lie within the filter bandwidth.
• If the input signal is completely outside filter bandwidth: no output signal (removed from SignalCollection).
• If the input signal partially overlaps the filter bandwidth: in this case, the output signal's power will be decreased according to the ratio of the overlap and the signal bandwidth will be constrained to only lie within the filter bandwidth. Also, the noise bandwidth will be constrained to only lie within the filter bandwidth.

Constructor Summary

Constructors

Modifier	Constructor and Description
	GpsPowerSpectralDensityFilter() Initializes a new instance.
protected	GpsPowerSpectralDensityFilter(GpsPowerSpectralDensityFilter existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.
	GpsPowerSpectralDensityFilter(SignalProcessor inputSignalProcessor, NavigationSignalType signalType, NavigationBlockType blockType, double noiseTemperature, double frequency, double lowerBandwidthLimit, double upperBandwidthLimit) Initialize a new instance based on the given parameters.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(GpsPowerSpectralDensityFilter other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(SignalFilter 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.
NavigationBlockType	getBlockType() Gets the block type of the GPS satellite broadcasting the signal passing through this filter.
SignalProcessor	getInputSignalProcessor() Gets the signal processor which produces the set of signals which this processor modifies.
SignalEvaluator	getSignalEvaluator(EvaluatorGroup group, SignalPropagationGraph graph) Returns a signal evaluator which takes the signals from the InputSignalProcessor (get / set) and constrains the bandwidth.
NavigationSignalType	getSignalType() Gets the signal type of the signal passing through this filter.
void	setBlockType(NavigationBlockType value) Sets the block type of the GPS satellite broadcasting the signal passing through this filter.
void	setInputSignalProcessor(SignalProcessor value) Sets the signal processor which produces the set of signals which this processor modifies.
void	setSignalType(NavigationSignalType value) Sets the signal type of the signal passing through this filter.

Methods inherited from class agi.foundation.communications.signalprocessing.SignalFilter

checkForSameDefinition, getFrequency, getLowerBandwidthLimit, getNoiseTemperature, getUpperBandwidthLimit, setFrequency, setLowerBandwidthLimit, setNoiseTemperature, setUpperBandwidthLimit

Methods inherited from class agi.foundation.communications.signalprocessing.SignalProcessor

checkForSameDefinition, getProcessingDelay, getService, getSignalEvaluator, getSignalOutput

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

GpsPowerSpectralDensityFilter

public GpsPowerSpectralDensityFilter()

Initializes a new instance.

GpsPowerSpectralDensityFilter

public GpsPowerSpectralDensityFilter(SignalProcessor inputSignalProcessor,
                                     @Nonnull
                                     NavigationSignalType signalType,
                                     @Nonnull
                                     NavigationBlockType blockType,
                                     double noiseTemperature,
                                     double frequency,
                                     double lowerBandwidthLimit,
                                     double upperBandwidthLimit)

Initialize a new instance based on the given parameters.

Parameters:

inputSignalProcessor - The source of the input signal.

signalType - The type of signal this filter will process.

blockType - The block type of the satellite broadcasting the signal.

noiseTemperature - The thermal noise temperature of the filter, in kelvin.

frequency - The center frequency of the filter, in Hz.

lowerBandwidthLimit - The negative offset to the lower boundary of the bandwidth, in hertz.

upperBandwidthLimit - The positive offset to the upper boundary of the bandwidth, in hertz.

GpsPowerSpectralDensityFilter

protected GpsPowerSpectralDensityFilter(@Nonnull
                                        GpsPowerSpectralDensityFilter 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(SignalFilter 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 SignalFilter

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(GpsPowerSpectralDensityFilter 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 GpsPowerSpectralDensityFilter.checkForSameDefinition(agi.foundation.communications.signalprocessing.SignalFilter) method.

Overrides:

computeCurrentDefinitionHashCode in class SignalFilter

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.

getInputSignalProcessor

public SignalProcessor getInputSignalProcessor()

Gets the signal processor which produces the set of signals which this processor modifies.

Specified by:

getInputSignalProcessor in class SignalProcessor

setInputSignalProcessor

public void setInputSignalProcessor(SignalProcessor value)

Sets the signal processor which produces the set of signals which this processor modifies.

Specified by:

setInputSignalProcessor in class SignalProcessor

getSignalType

@Nonnull
public final NavigationSignalType getSignalType()

Gets the signal type of the signal passing through this filter.

setSignalType

public final void setSignalType(@Nonnull
                                NavigationSignalType value)

Sets the signal type of the signal passing through this filter.

getBlockType

@Nonnull
public final NavigationBlockType getBlockType()

Gets the block type of the GPS satellite broadcasting the signal passing through this filter.

setBlockType

public final void setBlockType(@Nonnull
                               NavigationBlockType value)

Sets the block type of the GPS satellite broadcasting the signal passing through this filter.

getSignalEvaluator

public SignalEvaluator getSignalEvaluator(EvaluatorGroup group,
                                          SignalPropagationGraph graph)

Returns a signal evaluator which takes the signals from the InputSignalProcessor (get / set) and constrains the bandwidth.

Specified by:

getSignalEvaluator in interface ISignalSource

Specified by:

getSignalEvaluator in class SignalProcessor

Parameters:

group - The evaluator group in which to create evaluators.

graph - The graph of the communication links used to propagate signals.

Returns:

A signal evaluator which produces the filtered signals.

Throws:

ArgumentNullException - Thrown when group or graph is null.