Package org.orekit.propagation.events

Class FieldGroundAtNightDetector<T extends CalculusFieldElement<T>>

java.lang.Object

org.orekit.propagation.events.FieldAbstractDetector<D,T>

org.orekit.propagation.events.FieldAbstractTopocentricDetector<FieldGroundAtNightDetector<T>,T>

org.orekit.propagation.events.FieldGroundAtNightDetector<T>

All Implemented Interfaces:

FieldEventDetector<T>

public class FieldGroundAtNightDetector<T extends CalculusFieldElement<T>>
extends FieldAbstractTopocentricDetector<FieldGroundAtNightDetector<T>,T>

Detector for ground location being at night.

This detector is mainly useful for scheduling optical measurements (either passive telescope observation of satellites against the stars background or active satellite laser ranging).

The g function of this detector is positive when ground is at night (i.e. Sun is below dawn/dusk elevation angle).

Since:

13.1

Author:

Luc Maisonobe, Romain Serra

See Also:

GroundAtNightDetector

Field Summary

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

DEFAULT_MAX_CHECK, DEFAULT_MAX_ITER, DEFAULT_THRESHOLD

Constructor Summary

Constructors

Modifier	Constructor	Description
	FieldGroundAtNightDetector(TopocentricFrame topocentricFrame, ExtendedPositionProvider sun, T dawnDuskElevation, AtmosphericRefractionModel refractionModel)	Simple constructor.
protected	FieldGroundAtNightDetector(TopocentricFrame topocentricFrame, ExtendedPositionProvider sun, T dawnDuskElevation, AtmosphericRefractionModel refractionModel, FieldEventDetectionSettings<T> detectionSettings, FieldEventHandler<T> handler)	Private constructor.

Method Summary

Modifier and Type	Method	Description
protected FieldGroundAtNightDetector<T>	create(FieldEventDetectionSettings<T> detectionSettings, FieldEventHandler<T> newHandler)	Build a new instance.
boolean	dependsOnTimeOnly()	Method returning true if and only if the detection function g does not depend on dependent variables, just the independent one i.e. time.
T	g(FieldSpacecraftState<T> state)	Compute the value of the switching function.

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

getTopocentricFrame

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

checkIfForward, getDetectionSettings, 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.FieldEventDetector

finish, getMaxCheckInterval, getMaxIterationCount, getThreshold, reset

Constructor Detail

FieldGroundAtNightDetector

public FieldGroundAtNightDetector(TopocentricFrame topocentricFrame,
                                  ExtendedPositionProvider sun,
                                  T dawnDuskElevation,
                                  AtmosphericRefractionModel refractionModel)

Simple constructor.

Parameters:

topocentricFrame - ground location to check

sun - provider for Sun position

dawnDuskElevation - Sun elevation below which we consider night is dark enough (rad)

refractionModel - reference to refraction model (null if refraction should be ignored)

FieldGroundAtNightDetector

protected FieldGroundAtNightDetector(TopocentricFrame topocentricFrame,
                                     ExtendedPositionProvider sun,
                                     T dawnDuskElevation,
                                     AtmosphericRefractionModel refractionModel,
                                     FieldEventDetectionSettings<T> detectionSettings,
                                     FieldEventHandler<T> handler)

Private constructor.

Parameters:

topocentricFrame - ground location from which measurement is performed

sun - provider for Sun position

dawnDuskElevation - Sun elevation below which we consider night is dark enough (rad)

refractionModel - reference to refraction model (null if refraction should be ignored),

detectionSettings - event detection settings

handler - event handler to call at event occurrences

Method Detail

create

protected FieldGroundAtNightDetector<T> create(FieldEventDetectionSettings<T> detectionSettings,
                                               FieldEventHandler<T> newHandler)

Build a new instance.

Specified by:

create in class FieldAbstractDetector<FieldGroundAtNightDetector<T extends CalculusFieldElement<T>>,T extends CalculusFieldElement<T>>

Parameters:

detectionSettings - detection settings

newHandler - event handler to call at event occurrences

Returns:

a new instance of the appropriate sub-type

dependsOnTimeOnly

public boolean dependsOnTimeOnly()

Description copied from interface: FieldEventDetector

Method returning true if and only if the detection function g does not depend on dependent variables, just the independent one i.e. time. This information is used for performance in propagation.

Returns:

flag

g

public T g(FieldSpacecraftState<T> state)

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 of this detector is positive when ground is at night (i.e. Sun is below dawn/dusk elevation angle).

This function only depends on date, not on the actual position of the spacecraft.

Parameters:

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

Returns:

value of the switching function