org.orekit.propagation.events

Class EclipseDetector

java.lang.Object

org.orekit.propagation.events.AbstractDetector<EclipseDetector>

org.orekit.propagation.events.EclipseDetector

All Implemented Interfaces:

EventDetector

public class EclipseDetector
extends AbstractDetector<EclipseDetector>

Finder for satellite eclipse related events.

This class finds eclipse events, i.e. satellite within umbra (total eclipse) or penumbra (partial eclipse).

The occulted body is given through a PVCoordinatesProvider and its radius in meters. It is modeled as a sphere.

Since v10.0 the occulting body is a OneAxisEllipsoid, before it was modeled as a sphere.
It was changed to precisely model Solar eclipses by the Earth, especially for Low Earth Orbits.
If you want eclipses by a spherical occulting body, set its flattening to 0. when defining its OneAxisEllipsoid model..

The withUmbra() or withPenumbra() methods will tell you if the event is triggered when complete umbra/lighting is achieved or when entering/living the penumbra zone.
The default behavior is detecting complete umbra/lighting events.
If you want to have both, you'll need to set up two distinct detectors.

The default implementation behavior is to continue propagation when entering the eclipse and to stop propagation when exiting the eclipse.
This can be changed by calling AbstractDetector.withHandler(EventHandler) after construction.

Author:

Pascal Parraud, Luc Maisonobe

See Also:

Propagator.addEventDetector(EventDetector)

Field Summary

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

DEFAULT_MAX_ITER, DEFAULT_MAXCHECK, DEFAULT_THRESHOLD

Constructor Summary

Constructors

Constructor and Description
EclipseDetector(PVCoordinatesProvider occulted, double occultedRadius, OneAxisEllipsoid occulting) Build a new eclipse detector.

Method Summary

Modifier and Type	Method and Description
protected EclipseDetector	create(double newMaxCheck, double newThreshold, int nawMaxIter, EventHandler<? super EclipseDetector> newHandler) Build a new instance.
double	g(SpacecraftState s) Compute the value of the switching function.
PVCoordinatesProvider	getOcculted() Getter for the occulted body.
double	getOccultedRadius() Getter for the occultedRadius.
OneAxisEllipsoid	getOcculting() Getter for the occulting body.
boolean	getTotalEclipse() Get the total eclipse detection flag.
EclipseDetector	withPenumbra() Setup the detector to penumbra detection.
EclipseDetector	withUmbra() Setup the detector to full umbra detection.

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

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

EclipseDetector

public EclipseDetector(PVCoordinatesProvider occulted,
                       double occultedRadius,
                       OneAxisEllipsoid occulting)

Build a new eclipse detector.

The new instance is a total eclipse (umbra) detector with default values for maximal checking interval (AbstractDetector.DEFAULT_MAXCHECK) and convergence threshold (AbstractDetector.DEFAULT_THRESHOLD).

Parameters:

occulted - the body to be occulted

occultedRadius - the radius of the body to be occulted (m)

occulting - the occulting body

Since:

10.0

Method Detail

create

protected EclipseDetector create(double newMaxCheck,
                                 double newThreshold,
                                 int nawMaxIter,
                                 EventHandler<? super EclipseDetector> newHandler)

Build a new instance.

Specified by:

create in class AbstractDetector<EclipseDetector>

Parameters:

newMaxCheck - maximum checking interval (s)

newThreshold - convergence threshold (s)

nawMaxIter - 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

withUmbra

public EclipseDetector withUmbra()

Setup the detector to full umbra detection.

This will override a penumbra/umbra flag if it has been configured previously.

Returns:

a new detector with updated configuration (the instance is not changed)

Since:

6.1

See Also:

withPenumbra()

withPenumbra

public EclipseDetector withPenumbra()

Setup the detector to penumbra detection.

This will override a penumbra/umbra flag if it has been configured previously.

Returns:

a new detector with updated configuration (the instance is not changed)

Since:

6.1

See Also:

withUmbra()

getOcculting

public OneAxisEllipsoid getOcculting()

Getter for the occulting body.

Returns:

the occulting body

getOcculted

public PVCoordinatesProvider getOcculted()

Getter for the occulted body.

Returns:

the occulted body

getOccultedRadius

public double getOccultedRadius()

Getter for the occultedRadius.

Returns:

the occultedRadius

getTotalEclipse

public boolean getTotalEclipse()

Get the total eclipse detection flag.

Returns:

the total eclipse detection flag (true for umbra events detection, false for penumbra events detection)

g

public double g(SpacecraftState s)

Compute the value of the switching function. This function becomes negative when entering the region of shadow and positive when exiting.

Specified by:

g in interface EventDetector

Specified by:

g in class AbstractDetector<EclipseDetector>

Parameters:

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

Returns:

value of the switching function