Package org.orekit.propagation.events.functions

Class GroundAtNightEventFunction

java.lang.Object

org.orekit.propagation.events.functions.AbstractTopocentricEventFunction

org.orekit.propagation.events.functions.GroundAtNightEventFunction

All Implemented Interfaces:

EventFunction

public class GroundAtNightEventFunction
extends AbstractTopocentricEventFunction

Event function for ground location being at night.

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

Since:

14.0

Author:

Luc Maisonobe, Romain Serra

Constructor Summary

Constructors

Constructor	Description
GroundAtNightEventFunction(TopocentricFrame topocentricFrame, ExtendedPositionProvider sun, double dawnDuskElevation, AtmosphericRefractionModel refractionModel)	Private constructor.

Method Summary

Modifier and Type	Method	Description
boolean	dependsOnTimeOnly()	Method returning true if and only if the event function does not depend on dependent variables, just the independent one i.e. time.
<T extends CalculusFieldElement<T>> T	value(FieldSpacecraftState<T> state)	Evaluate Field function.
double	value(SpacecraftState state)	Evaluate function.

Methods inherited from class org.orekit.propagation.events.functions.AbstractTopocentricEventFunction

getTopocentricFrame

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.functions.EventFunction

dependsOnMainVariablesOnly

Constructor Details

GroundAtNightEventFunction

public GroundAtNightEventFunction(TopocentricFrame topocentricFrame,
 ExtendedPositionProvider sun,
 double dawnDuskElevation,
 AtmosphericRefractionModel refractionModel)

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),

Method Details

value

public double value(SpacecraftState state)

Description copied from interface: EventFunction

Evaluate function.

Parameters:

state - spacecraft state

Returns:

value

value

public <T extends CalculusFieldElement<T>> T value(FieldSpacecraftState<T> state)

Evaluate Field function. By default, calls the non-Field version. This is suitable for detection but not be for applications like automatic differentiation, where a proper implementation should be used instead.

The function 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.

Type Parameters:

T - field type

Parameters:

state - spacecraft state

Returns:

value

dependsOnTimeOnly

public boolean dependsOnTimeOnly()

Description copied from interface: EventFunction

Method returning true if and only if the event function does not depend on dependent variables, just the independent one i.e. time. This information is used for performance in propagation and derivatives correction with switches in the dynamics.

Returns:

flag