org.orekit.propagation.events

Class FieldOfViewDetector

java.lang.Object

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

org.orekit.propagation.events.FieldOfViewDetector

All Implemented Interfaces:

Serializable, EventDetector

public class FieldOfViewDetector
extends AbstractDetector<FieldOfViewDetector>

Finder for target entry/exit events with respect to a satellite sensor Field Of View.

The default implementation behavior is to continue propagation at FOV entry and to stop propagation at FOV exit. This can be changed by calling AbstractDetector.withHandler(EventHandler) after construction.

Since:

7.1

Author:

Luc Maisonobe

See Also:

Propagator.addEventDetector(EventDetector), CircularFieldOfViewDetector, 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
FieldOfViewDetector(PVCoordinatesProvider pvTarget, FieldOfView fov) Build a new instance.

Method Summary

Modifier and Type	Method and Description
protected FieldOfViewDetector	create(double newMaxCheck, double newThreshold, int newMaxIter, EventHandler<? super FieldOfViewDetector> newHandler) Build a new instance.
double	g(SpacecraftState s) Compute the value of the switching function.
FieldOfView	getFieldOfView() Get the Field Of View.
PVCoordinatesProvider	getPVTarget() Get the position/velocity provider of the target .

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

FieldOfViewDetector

public FieldOfViewDetector(PVCoordinatesProvider pvTarget,
                           FieldOfView fov)

Build a new instance.

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

Parameters:

pvTarget - Position/velocity provider of the considered target

fov - Field Of View

Method Detail

create

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

Build a new instance.

Specified by:

create in class AbstractDetector<FieldOfViewDetector>

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

getPVTarget

public PVCoordinatesProvider getPVTarget()

Get the position/velocity provider of the target .

Returns:

the position/velocity provider of the target

getFieldOfView

public FieldOfView getFieldOfView()

Get the Field Of View.

Returns:

Field Of View

g

public double g(SpacecraftState s)
         throws OrekitException

Compute the value of the switching function. This function must be continuous (at least in its roots neighborhood), as the integrator will need to find its roots to locate the events.

The g function value is the angular offset between the target and the Field Of View boundary. It is negative if the target is visible within the Field Of View and positive if it is outside of the Field Of View, including the margin.

As per the previous definition, when the target enters the Field Of View, a decreasing event is generated, and when the target leaves the Field Of View, an increasing event is generated.

Specified by:

g in interface EventDetector

Specified by:

g in class AbstractDetector<FieldOfViewDetector>

Parameters:

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

Returns:

value of the switching function

Throws:

OrekitException - if some specific error occurs