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

Modifier	Constructor and Description
protected	EclipseDetector(AdaptableInterval maxCheck, double threshold, int maxIter, EventHandler handler, OccultationEngine occultationEngine, double margin, boolean totalEclipse) Protected constructor with full parameters.
	EclipseDetector(ExtendedPVCoordinatesProvider occulted, double occultedRadius, OneAxisEllipsoid occulting) Build a new eclipse detector.
	EclipseDetector(OccultationEngine occultationEngine) Build a new eclipse detector.

Method Summary

Modifier and Type	Method and Description
protected EclipseDetector	create(AdaptableInterval newMaxCheck, double newThreshold, int nawMaxIter, EventHandler newHandler) Build a new instance.
double	g(SpacecraftState s) Compute the value of the switching function.
double	getMargin() Get the angular margin used for eclipse detection.
OccultationEngine	getOccultationEngine() Get the occultation engine.
boolean	getTotalEclipse() Get the total eclipse detection flag.
EclipseDetector	withMargin(double newMargin) Setup a margin to angle detection.
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

getHandler, getMaxCheckInterval, getMaxIterationCount, getThreshold, init, isForward, withHandler, withMaxCheck, 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(ExtendedPVCoordinatesProvider 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:

12.0

EclipseDetector

public EclipseDetector(OccultationEngine occultationEngine)

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:

occultationEngine - occultation engine

Since:

12.0

EclipseDetector

protected EclipseDetector(AdaptableInterval maxCheck,
                          double threshold,
                          int maxIter,
                          EventHandler handler,
                          OccultationEngine occultationEngine,
                          double margin,
                          boolean totalEclipse)

Protected constructor with full parameters.

This constructor is not public as users are expected to use the builder API with the various withXxx() methods to set up the instance in a readable manner without using a huge amount of parameters.

Parameters:

maxCheck - maximum checking interval

threshold - convergence threshold (s)

maxIter - maximum number of iterations in the event time search

handler - event handler to call at event occurrences

occultationEngine - occultation engine

margin - to apply to eclipse angle (rad)

totalEclipse - umbra (true) or penumbra (false) detection flag

Since:

12.0

Method Detail

create

protected EclipseDetector create(AdaptableInterval newMaxCheck,
                                 double newThreshold,
                                 int nawMaxIter,
                                 EventHandler 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()

withMargin

public EclipseDetector withMargin(double newMargin)

Setup a margin to angle detection.

A positive margin implies eclipses are "larger" hence entry occurs earlier and exit occurs later than a detector with 0 margin.

Parameters:

newMargin - angular margin to apply to eclipse detection (rad)

Returns:

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

Since:

12.0

getMargin

public double getMargin()

Get the angular margin used for eclipse detection.

Returns:

angular margin used for eclipse detection (rad)

Since:

12.0

getOccultationEngine

public OccultationEngine getOccultationEngine()

Get the occultation engine.

Returns:

occultation engine

Since:

12.0

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