Package org.orekit.propagation.events

Class GroundFieldOfViewDetector

java.lang.Object

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

org.orekit.propagation.events.GroundFieldOfViewDetector

All Implemented Interfaces:

EventDetector

public class GroundFieldOfViewDetector
extends AbstractDetector<GroundFieldOfViewDetector>

Finder for satellite entry/exit events with respect to a sensor Field Of View attached to an arbitrary frame.

If you only want to compute access times then you should probably use ElevationDetector.

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, Evan Ward

See Also:

• Propagator.addEventDetector(EventDetector)
• FieldOfViewDetector
• ElevationDetector

Field Summary

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

DEFAULT_MAX_CHECK, DEFAULT_MAX_ITER, DEFAULT_THRESHOLD

Constructor Summary

Constructors

Modifier	Constructor	Description
	GroundFieldOfViewDetector(Frame frame, FieldOfView fov)	Build a new instance.
protected	GroundFieldOfViewDetector(EventDetectionSettings detectionSettings, EventHandler handler, Frame frame, FieldOfView fov)	Protected constructor with full parameters.

Method Summary

Modifier and Type	Method	Description
protected GroundFieldOfViewDetector	create(EventDetectionSettings detectionSettings, EventHandler newHandler)	Build a new instance.
double	g(SpacecraftState s)	Compute the value of the switching function.
FieldOfView	getFOV()	Get the Field Of View.
Frame	getFrame()	Get the sensor reference frame.

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

checkIfForward, getDetectionSettings, getEventFunction, getHandler, init, isForward, withDetectionSettings, withHandler, withMaxCheck, withMaxCheck, withMaxIter, withThreshold

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.orekit.propagation.events.EventDetector

finish, getMaxCheckInterval, getMaxIterationCount, getThreshold, reset

Constructor Details

GroundFieldOfViewDetector

public GroundFieldOfViewDetector(Frame frame,
 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:

frame - the reference frame attached to the sensor.

fov - Field Of View of the sensor.

Since:

10.1

GroundFieldOfViewDetector

protected GroundFieldOfViewDetector(EventDetectionSettings detectionSettings,
 EventHandler handler,
 Frame frame,
 FieldOfView fov)

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:

detectionSettings - event detection settings

handler - event handler to call at event occurrences

frame - the reference frame attached to the sensor.

fov - Field Of View of the sensor.

Since:

13.0

Method Details

create

protected GroundFieldOfViewDetector create(EventDetectionSettings detectionSettings,
 EventHandler newHandler)

Build a new instance.

Specified by:

create in class AbstractDetector<GroundFieldOfViewDetector>

Parameters:

detectionSettings - detection settings

newHandler - event handler to call at event occurrences

Returns:

a new instance of the appropriate sub-type

getFrame

public Frame getFrame()

Get the sensor reference frame.

Returns:

the reference frame attached to the sensor.

getFOV

public FieldOfView getFOV()

Get the Field Of View.

Returns:

Field Of View

Since:

10.1

g

public double g(SpacecraftState s)

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 satellite and the Field Of View boundary. It is negative if the satellite 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 satellite enters the Field Of View, a decreasing event is generated, and when the satellite leaves the Field Of View, an increasing event is generated.

Parameters:

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

Returns:

value of the switching function