agi.foundation.geometry

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

Class AxesFromBankAngle

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.geometry.Axes

agi.foundation.geometry.AxesFromBankAngle

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable, IServiceProvider

public class AxesFromBankAngle
extends Axes

An Axes defining a first order representation for an aircraft in steady flight with the bank angles specified by changes in the horizontal acceleration vector. The bank angle is determined by assuming steady flight and calculating the angle necessary to provide the corresponding horizontal acceleration. The axes will examine the acceleration around the special times of interest and determine how much time is needed before and after that point in order to transition between the two bank angles based on the given roll rate. When no horizontal acceleration is present, this is the same as an axes aligned with the x axis along the velocity and the z axis constrained toward nadir.

Note that while this will attempt to use the TargetRollRate (get / set), if there is a sequence of banking maneuvers in quick succession the TargetRollRate (get / set) will not be feasible. In this case, the roll rate will exceed the target as necessary.

Constructor Summary

Constructors

Modifier	Constructor and Description
	AxesFromBankAngle() Create a new instance.
protected	AxesFromBankAngle(AxesFromBankAngle existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.
	AxesFromBankAngle(Point position, CentralBody centralBody, double surfaceGravity, List<JulianDate> specialTimes, double targetRollRate) Create a new instance based on the given point and special times of interest.
	AxesFromBankAngle(PropagatedRoute route, double surfaceGravity, double targetRollRate) Create a new instance based on the given route, banking around turns, and transitioning smoothly from one bank condition to another around transition points in the route.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(Axes other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(AxesFromBankAngle 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 (get / set) with respect to which these Axes are defined.
AxesEvaluator	getEvaluator(EvaluatorGroup group) Gets an evaluator that can be used to find the transformation from this axes' parent axes to this axes represented by a Motion<UnitQuaternion, Cartesian> at a given JulianDate.
double	getMaximumRollRate() Gets the maximum roll rate to allow during the trajectory before throwing an exception.
Point	getPosition() Gets the Point representing the position of the platform and its derivatives.
List<JulianDate>	getSpecialTimes() Gets the list of special times of interest at which to transition from one bank angle to the next.
double	getSurfaceGravity() Gets the value of the surface gravity corresponding to the CentralBody (get / set), in meters per second squared.
double	getTargetRollRate() Gets the desired roll rate at which to transition from one bank angle to the next, in radians per second.
void	setCentralBody(CentralBody value) Sets the CentralBody (get / set) with respect to which these Axes are defined.
void	setMaximumRollRate(double value) Sets the maximum roll rate to allow during the trajectory before throwing an exception.
void	setPosition(Point value) Sets the Point representing the position of the platform and its derivatives.
void	setSpecialTimes(List<JulianDate> value) Sets the list of special times of interest at which to transition from one bank angle to the next.
void	setSurfaceGravity(double value) Sets the value of the surface gravity corresponding to the CentralBody (get / set), in meters per second squared.
void	setTargetRollRate(double value) Sets the desired roll rate at which to transition from one bank angle to the next, in radians per second.

Methods inherited from class agi.foundation.geometry.Axes

checkForSameDefinition, getEvaluator, getRoot, getService, getVectorElement, getVectorElement

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

AxesFromBankAngle

public AxesFromBankAngle()

Create a new instance.

AxesFromBankAngle

public AxesFromBankAngle(Point position,
                         CentralBody centralBody,
                         double surfaceGravity,
                         List<JulianDate> specialTimes,
                         double targetRollRate)

Create a new instance based on the given point and special times of interest.

Parameters:

position - The time dynamic position of the platform.

centralBody - The central body with respect to which these axes are defined.

surfaceGravity - The surface gravity for the centralBody, in meters per second squared.

specialTimes - The special times of interest to examine when determining the transitions between bank angles.

targetRollRate - The desired roll rate at which to transition from one bank angle to the next, in radians per second.

AxesFromBankAngle

public AxesFromBankAngle(@Nonnull
                         PropagatedRoute route,
                         double surfaceGravity,
                         double targetRollRate)

Create a new instance based on the given route, banking around turns, and transitioning smoothly from one bank condition to another around transition points in the route.

Parameters:

route - The route along which to provide the attitude.

surfaceGravity - The surface gravity for the CentralBody (get), in meters per second squared.

targetRollRate - The desired roll rate at which to transition from one bank angle to the next, in radians per second.

AxesFromBankAngle

protected AxesFromBankAngle(@Nonnull
                            AxesFromBankAngle 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(Axes 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 Axes

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(AxesFromBankAngle 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 AxesFromBankAngle.checkForSameDefinition(agi.foundation.geometry.Axes) method.

Overrides:

computeCurrentDefinitionHashCode in class Axes

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.

getPosition

public final Point getPosition()

Gets the Point representing the position of the platform and its derivatives.

setPosition

public final void setPosition(Point value)

Sets the Point representing the position of the platform and its derivatives.

getCentralBody

public final CentralBody getCentralBody()

Gets the CentralBody (get / set) with respect to which these Axes are defined.

setCentralBody

public final void setCentralBody(CentralBody value)

Sets the CentralBody (get / set) with respect to which these Axes are defined.

getSurfaceGravity

public final double getSurfaceGravity()

Gets the value of the surface gravity corresponding to the CentralBody (get / set), in meters per second squared. By default, this value corresponds to Constants.EarthSurfaceGravity.

setSurfaceGravity

public final void setSurfaceGravity(double value)

Sets the value of the surface gravity corresponding to the CentralBody (get / set), in meters per second squared. By default, this value corresponds to Constants.EarthSurfaceGravity.

getSpecialTimes

public final List<JulianDate> getSpecialTimes()

Gets the list of special times of interest at which to transition from one bank angle to the next. These axes will consider each of the times to determine if there is a discontinuity and then attempt to create a smooth transition from the previous bank angle to the next using the specified TargetRollRate (get / set).

setSpecialTimes

public final void setSpecialTimes(List<JulianDate> value)

Sets the list of special times of interest at which to transition from one bank angle to the next. These axes will consider each of the times to determine if there is a discontinuity and then attempt to create a smooth transition from the previous bank angle to the next using the specified TargetRollRate (get / set).

getTargetRollRate

public final double getTargetRollRate()

Gets the desired roll rate at which to transition from one bank angle to the next, in radians per second.

setTargetRollRate

public final void setTargetRollRate(double value)

Sets the desired roll rate at which to transition from one bank angle to the next, in radians per second.

getMaximumRollRate

public final double getMaximumRollRate()

Gets the maximum roll rate to allow during the trajectory before throwing an exception. By default, the value is positive infinity, indicating that the axes will violate the TargetRollRate (get / set) if there are several SpecialTimes (get / set) in close proximity preventing a feasible transition with the TargetRollRate (get / set). If the resulting roll rate is greater than the maximum the call to AxesFromBankAngle.getEvaluator(agi.foundation.EvaluatorGroup) will throw an IllegalStateException.

setMaximumRollRate

public final void setMaximumRollRate(double value)

Sets the maximum roll rate to allow during the trajectory before throwing an exception. By default, the value is positive infinity, indicating that the axes will violate the TargetRollRate (get / set) if there are several SpecialTimes (get / set) in close proximity preventing a feasible transition with the TargetRollRate (get / set). If the resulting roll rate is greater than the maximum the call to AxesFromBankAngle.getEvaluator(agi.foundation.EvaluatorGroup) will throw an IllegalStateException.

getEvaluator

public AxesEvaluator getEvaluator(EvaluatorGroup group)

Gets an evaluator that can be used to find the transformation from this axes' parent axes to this axes represented by a Motion<UnitQuaternion, Cartesian> at a given JulianDate. Consider using the methods of GeometryTransformer instead of calling this method directly.

Specified by:

getEvaluator in class Axes

Parameters:

group - The group with which to associate the new evaluator. By grouping evaluators that are often evaluated at the same Julian dates, common computations can be performed only once for the entire group instead of multiple times for each evaluator.

Returns:

An evaluator for this Axes.