org.orekit.propagation.events

Class GeographicZoneDetector

java.lang.Object

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

org.orekit.propagation.events.GeographicZoneDetector

All Implemented Interfaces:

Serializable, EventDetector

public class GeographicZoneDetector
extends AbstractDetector<GeographicZoneDetector>

Detector for entry/exit of a zone defined by geographic boundaries.

This detector identifies when a spacecraft crosses boundaries of general shapes defined on the surface of the globe. Typical shapes of interest can be countries, land masses or physical areas like the south atlantic anomaly. Shapes can be arbitrarily complicated: convex or non-convex, in one piece or several non-connected islands, they can include poles, they can have holes like the Caspian Sea (this would be a hole only if one is interested in land masses, of course). Complex shapes involve of course more computing time than simple shapes.

Since:

6.2

Author:

Luc Maisonobe

See Also:

FootprintOverlapDetector, Serialized Form

Field Summary

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

DEFAULT_MAX_ITER, DEFAULT_MAXCHECK, DEFAULT_THRESHOLD

Constructor Summary

Constructors

Constructor and Description
GeographicZoneDetector(BodyShape body, SphericalPolygonsSet zone, double margin) Build a new detector.
GeographicZoneDetector(double maxCheck, double threshold, BodyShape body, SphericalPolygonsSet zone, double margin) Build a detector.

Method Summary

Modifier and Type	Method and Description
protected GeographicZoneDetector	create(double newMaxCheck, double newThreshold, int newMaxIter, EventHandler<? super GeographicZoneDetector> newHandler) Build a new instance.
double	g(SpacecraftState s) Compute the value of the detection function.
BodyShape	getBody() Get the body on which the geographic zone is defined.
double	getMargin() Get the angular margin to apply (radians).
SphericalPolygonsSet	getZone() Get the geographic zone.
GeographicZoneDetector	withMargin(double newMargin) Setup the detector margin.

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

GeographicZoneDetector

public GeographicZoneDetector(BodyShape body,
                              SphericalPolygonsSet zone,
                              double margin)

Build a new detector.

The new instance uses default values for maximal checking interval (AbstractDetector.DEFAULT_MAXCHECK) and convergence threshold (AbstractDetector.DEFAULT_THRESHOLD).

Parameters:

body - body on which the geographic zone is defined

zone - geographic zone to consider

margin - angular margin to apply to the zone

GeographicZoneDetector

public GeographicZoneDetector(double maxCheck,
                              double threshold,
                              BodyShape body,
                              SphericalPolygonsSet zone,
                              double margin)

Build a detector.

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

body - body on which the geographic zone is defined

zone - geographic zone to consider

margin - angular margin to apply to the zone

Method Detail

create

protected GeographicZoneDetector create(double newMaxCheck,
                                        double newThreshold,
                                        int newMaxIter,
                                        EventHandler<? super GeographicZoneDetector> newHandler)

Build a new instance.

Specified by:

create in class AbstractDetector<GeographicZoneDetector>

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

withMargin

public GeographicZoneDetector withMargin(double newMargin)

Setup the detector margin.

Parameters:

newMargin - angular margin to apply to the zone

Returns:

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

getBody

public BodyShape getBody()

Get the body on which the geographic zone is defined.

Returns:

body on which the geographic zone is defined

getZone

public SphericalPolygonsSet getZone()

Get the geographic zone.

Returns:

the geographic zone

getMargin

public double getMargin()

Get the angular margin to apply (radians).

Returns:

the angular margin to apply (radians)

g

public double g(SpacecraftState s)
         throws OrekitException

Compute the value of the detection function.

The value is the signed distance to boundary, minus the margin. It is positive if the spacecraft is outside of the zone and negative if it is inside.

Specified by:

g in interface EventDetector

Specified by:

g in class AbstractDetector<GeographicZoneDetector>

Parameters:

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

Returns:

signed distance to boundary minus the margin

Throws:

OrekitException - if some specific error occurs