Package org.orekit.propagation.events

Class AltitudeDetector

java.lang.Object

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

org.orekit.propagation.events.AltitudeDetector

All Implemented Interfaces:

Serializable, EventDetector

public class AltitudeDetector
extends AbstractDetector<AltitudeDetector>

Finder for satellite altitude crossing events.

This class finds altitude events (i.e. satellite crossing a predefined altitude level above ground).

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

Author:

Luc Maisonobe

See Also:

Propagator.addEventDetector(EventDetector), Serialized Form

Field Summary

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

DEFAULT_MAX_ITER, DEFAULT_MAXCHECK, DEFAULT_THRESHOLD

Constructor Summary

Constructors

Constructor	Description
AltitudeDetector(double maxCheck, double threshold, double altitude, BodyShape bodyShape)	Build a new altitude detector.
AltitudeDetector(double maxCheck, double altitude, BodyShape bodyShape)	Build a new altitude detector.
AltitudeDetector(double altitude, BodyShape bodyShape)	Build a new altitude detector.

Method Summary

Modifier and Type	Method	Description
protected AltitudeDetector	create(double newMaxCheck, double newThreshold, int newMaxIter, EventHandler<? super AltitudeDetector> newHandler)	Build a new instance.
double	g(SpacecraftState s)	Compute the value of the switching function.
double	getAltitude()	Get the threshold altitude value.
BodyShape	getBodyShape()	Get the body shape.

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

AltitudeDetector

public AltitudeDetector(double altitude,
                        BodyShape bodyShape)

Build a new altitude detector.

This simple constructor takes default values for maximal checking interval (AbstractDetector.DEFAULT_MAXCHECK) and convergence threshold (AbstractDetector.DEFAULT_THRESHOLD).

Parameters:

altitude - threshold altitude value

bodyShape - body shape with respect to which altitude should be evaluated

AltitudeDetector

public AltitudeDetector(double maxCheck,
                        double altitude,
                        BodyShape bodyShape)

Build a new altitude detector.

This simple constructor takes default value for convergence threshold (AbstractDetector.DEFAULT_THRESHOLD).

The maximal interval between altitude checks should be smaller than the half duration of the minimal pass to handle, otherwise some short passes could be missed.

Parameters:

maxCheck - maximal checking interval (s)

altitude - threshold altitude value (m)

bodyShape - body shape with respect to which altitude should be evaluated

AltitudeDetector

public AltitudeDetector(double maxCheck,
                        double threshold,
                        double altitude,
                        BodyShape bodyShape)

Build a new altitude detector.

The maximal interval between altitude checks should be smaller than the half duration of the minimal pass to handle, otherwise some short passes could be missed.

The maximal interval between altitude checks should be smaller than the half duration of the minimal pass to handle, otherwise some short passes could be missed.

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

altitude - threshold altitude value (m)

bodyShape - body shape with respect to which altitude should be evaluated

Method Detail

create

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

Build a new instance.

Specified by:

create in class AbstractDetector<AltitudeDetector>

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

getAltitude

public double getAltitude()

Get the threshold altitude value.

Returns:

the threshold altitude value (m)

getBodyShape

public BodyShape getBodyShape()

Get the body shape.

Returns:

the body shape

g

public double g(SpacecraftState s)

Compute the value of the switching function. This function measures the difference between the current altitude and the threshold altitude.

Specified by:

g in interface EventDetector

Specified by:

g in class AbstractDetector<AltitudeDetector>

Parameters:

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

Returns:

value of the switching function