Package org.orekit.propagation.events

Class FieldElevationExtremumDetector<T extends CalculusFieldElement<T>>

java.lang.Object

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

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

Type Parameters:

T - type of the field element

All Implemented Interfaces:

FieldEventDetector<T>

public class FieldElevationExtremumDetector<T extends CalculusFieldElement<T>>
extends FieldAbstractDetector<FieldElevationExtremumDetector<T>,T>

Detector for elevation extremum with respect to a ground point.

This detector identifies when a spacecraft reaches its extremum elevation with respect to a ground point.

As in most cases only the elevation maximum is needed and the minimum is often irrelevant, this detector is often wrapped into an event slope filter configured with FilterType.TRIGGER_ONLY_DECREASING_EVENTS (i.e. when the elevation derivative decreases from positive values to negative values, which correspond to a maximum). Setting up this filter saves some computation time as the elevation minimum occurrences are not even looked at. It is however still often necessary to do an additional filtering

Since:

12.0

Author:

Luc Maisonobe

Field Summary

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

DEFAULT_MAX_ITER, DEFAULT_MAXCHECK, DEFAULT_THRESHOLD

Constructor Summary

Constructors

Modifier	Constructor	Description
	FieldElevationExtremumDetector(Field<T> field, TopocentricFrame topo)	Build a new detector.
protected	FieldElevationExtremumDetector(FieldAdaptableInterval<T> maxCheck, T threshold, int maxIter, FieldEventHandler<T> handler, TopocentricFrame topo)	Protected constructor with full parameters.
	FieldElevationExtremumDetector(T maxCheck, T threshold, TopocentricFrame topo)	Build a detector.

Method Summary

Modifier and Type	Method	Description
protected FieldElevationExtremumDetector<T>	create(FieldAdaptableInterval<T> newMaxCheck, T newThreshold, int newMaxIter, FieldEventHandler<T> newHandler)	Build a new instance.
T	g(FieldSpacecraftState<T> s)	Compute the value of the detection function.
T	getElevation(FieldSpacecraftState<T> s)	Get the elevation value.
TopocentricFrame	getTopocentricFrame()	Returns the topocentric frame centered on ground point.

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

getHandler, getMaxCheckInterval, getMaxIterationCount, getThreshold, init, isForward, withHandler, withMaxCheck, withMaxCheck, withMaxIter, withThreshold

Methods inherited from class java.lang.Object

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

Constructor Detail

FieldElevationExtremumDetector

public FieldElevationExtremumDetector(Field<T> field,
                                      TopocentricFrame topo)

Build a new detector.

The new instance uses default values for maximal checking interval (FieldAbstractDetector.DEFAULT_MAXCHECK) and convergence threshold (FieldAbstractDetector.DEFAULT_THRESHOLD).

Parameters:

field - field to which elements belong

topo - topocentric frame centered on ground point

FieldElevationExtremumDetector

public FieldElevationExtremumDetector(T maxCheck,
                                      T threshold,
                                      TopocentricFrame topo)

Build a detector.

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

topo - topocentric frame centered on ground point

FieldElevationExtremumDetector

protected FieldElevationExtremumDetector(FieldAdaptableInterval<T> maxCheck,
                                         T threshold,
                                         int maxIter,
                                         FieldEventHandler<T> handler,
                                         TopocentricFrame topo)

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:

maxCheck - maximum checking interval

threshold - convergence threshold (s)

maxIter - maximum number of iterations in the event time search

handler - event handler to call at event occurrences

topo - topocentric frame centered on ground point

Method Detail

create

protected FieldElevationExtremumDetector<T> create(FieldAdaptableInterval<T> newMaxCheck,
                                                   T newThreshold,
                                                   int newMaxIter,
                                                   FieldEventHandler<T> newHandler)

Build a new instance.

Specified by:

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

Parameters:

newMaxCheck - maximum checking interval

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

getTopocentricFrame

public TopocentricFrame getTopocentricFrame()

Returns the topocentric frame centered on ground point.

Returns:

topocentric frame centered on ground point

getElevation

public T getElevation(FieldSpacecraftState<T> s)

Get the elevation value.

Parameters:

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

Returns:

spacecraft elevation

g

public T g(FieldSpacecraftState<T> s)

Compute the value of the detection function.

The value is the spacecraft elevation first time derivative.

Specified by:

g in interface FieldEventDetector<T extends CalculusFieldElement<T>>

Specified by:

g in class FieldAbstractDetector<FieldElevationExtremumDetector<T extends CalculusFieldElement<T>>,T extends CalculusFieldElement<T>>

Parameters:

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

Returns:

spacecraft elevation first time derivative