Package org.orekit.propagation.events

Class FieldNodeDetector<T extends RealFieldElement<T>>

java.lang.Object

org.orekit.propagation.events.FieldAbstractDetector<FieldNodeDetector<T>,T>

org.orekit.propagation.events.FieldNodeDetector<T>

All Implemented Interfaces:

FieldEventDetector<T>

public class FieldNodeDetector<T extends RealFieldElement<T>>
extends FieldAbstractDetector<FieldNodeDetector<T>,T>

Finder for node crossing events.

This class finds equator crossing events (i.e. ascending or descending node crossing).

The default implementation behavior is to continue propagation at descending node crossing and to stop propagation at ascending node crossing. This can be changed by calling FieldAbstractDetector.withHandler(FieldEventHandler) after construction.

Beware that node detection will fail for almost equatorial orbits. If for example a node detector is used to trigger an ImpulseManeuver and the maneuver turn the orbit plane to equator, then the detector may completely fail just after the maneuver has been performed! This is a real case that has been encountered during validation ...

Author:

Luc Maisonobe

See Also:

FieldPropagator.addEventDetector(FieldEventDetector)

Field Summary

Fields inherited from class org.orekit.propagation.events.FieldAbstractDetector

DEFAULT_MAX_ITER, DEFAULT_MAXCHECK, DEFAULT_THRESHOLD

Constructor Summary

Constructors

Constructor	Description
FieldNodeDetector(FieldOrbit<T> orbit, Frame frame)	Build a new instance.
FieldNodeDetector(T threshold, FieldOrbit<T> orbit, Frame frame)	Build a new instance.

Method Summary

Modifier and Type	Method	Description
protected FieldNodeDetector<T>	create(T newMaxCheck, T newThreshold, int newMaxIter, FieldEventHandler<? super FieldNodeDetector<T>,T> newHandler)	Build a new instance.
T	g(FieldSpacecraftState<T> s)	Compute the value of the switching function.
Frame	getFrame()	Get the frame in which the equator is defined.

Methods inherited from class org.orekit.propagation.events.FieldAbstractDetector

eventOccurred, getHandler, getMaxCheckInterval, getMaxIterationCount, getThreshold, init, isForward, resetState, withHandler, withMaxCheck, withMaxIter, withThreshold

Methods inherited from class java.lang.Object

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

Constructor Detail

FieldNodeDetector

public FieldNodeDetector(FieldOrbit<T> orbit,
                         Frame frame)

Build a new instance.

The orbit is used only to set an upper bound for the max check interval to period/3 and to set the convergence threshold according to orbit size.

Parameters:

orbit - initial orbit

frame - frame in which the equator is defined (typical values are EME2000 or ITRF)

FieldNodeDetector

public FieldNodeDetector(T threshold,
                         FieldOrbit<T> orbit,
                         Frame frame)

Build a new instance.

The orbit is used only to set an upper bound for the max check interval to period/3.

Parameters:

threshold - convergence threshold (s)

orbit - initial orbit

frame - frame in which the equator is defined (typical values are EME2000 or ITRF)

Method Detail

create

protected FieldNodeDetector<T> create(T newMaxCheck,
                                      T newThreshold,
                                      int newMaxIter,
                                      FieldEventHandler<? super FieldNodeDetector<T>,T> newHandler)

Build a new instance.

Specified by:

create in class FieldAbstractDetector<FieldNodeDetector<T extends RealFieldElement<T>>,T extends RealFieldElement<T>>

Parameters:

newMaxCheck - maximum checking interval (s)

newThreshold - convergence threshold (s)

newMaxIter - maximum number of iterations in the event time search

newHandler - event handler to call at event occurrences

Returns:

a new instance of the appropriate sub-type

getFrame

public Frame getFrame()

Get the frame in which the equator is defined.

Returns:

the frame in which the equator is defined

g

public T g(FieldSpacecraftState<T> s)
    throws OrekitException

Compute the value of the switching function. This function computes the Z position in the defined frame.

Specified by:

g in interface FieldEventDetector<T extends RealFieldElement<T>>

Specified by:

g in class FieldAbstractDetector<FieldNodeDetector<T extends RealFieldElement<T>>,T extends RealFieldElement<T>>

Parameters:

s - the current state information: date, kinematics, attitude

Returns:

value of the switching function

Throws:

OrekitException - if some specific error occurs