org.orekit.propagation.events

Class AbstractDetector<T extends AbstractDetector<T>>

java.lang.Object

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

All Implemented Interfaces:

EventDetector

Direct Known Subclasses:

AlignmentDetector, AltitudeDetector, AngularSeparationDetector, AngularSeparationFromSatelliteDetector, ApsideDetector, BooleanDetector, DateDetector, EclipseDetector, ElevationDetector, ElevationExtremumDetector, EventEnablingPredicateFilter, EventShifter, EventSlopeFilter, FieldOfViewDetector, FootprintOverlapDetector, FunctionalDetector, GeographicZoneDetector, GroundAtNightDetector, GroundFieldOfViewDetector, HaloXZPlaneCrossingDetector, ImpulseManeuver, InterSatDirectViewDetector, LatitudeCrossingDetector, LatitudeExtremumDetector, LongitudeCrossingDetector, LongitudeExtremumDetector, MagneticFieldDetector, NegateDetector, NodeDetector, ParameterDrivenDateIntervalDetector, PositionAngleDetector

public abstract class AbstractDetector<T extends AbstractDetector<T>>
extends Object
implements EventDetector

Common parts shared by several orbital events finders.

Author:

Luc Maisonobe

See Also:

Propagator.addEventDetector(EventDetector)

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_MAX_ITER Default maximum number of iterations in the event time search.
static double	DEFAULT_MAXCHECK Default maximum checking interval (s).
static double	DEFAULT_THRESHOLD Default convergence threshold (s).

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractDetector(double maxCheck, double threshold, int maxIter, EventHandler<? super T> handler) Build a new instance.

Method Summary

Modifier and Type	Method and Description
protected abstract T	create(double newMaxCheck, double newThreshold, int newMaxIter, EventHandler<? super T> newHandler) Build a new instance.
Action	eventOccurred(SpacecraftState s, boolean increasing) Handle the event.
abstract double	g(SpacecraftState s) Compute the value of the switching function.
EventHandler<? super T>	getHandler() Get the handler.
double	getMaxCheckInterval() Get maximal time interval between switching function checks.
int	getMaxIterationCount() Get maximal number of iterations in the event time search.
double	getThreshold() Get the convergence threshold in the event time search.
void	init(SpacecraftState s0, AbsoluteDate t) Initialize event handler at the start of a propagation.
boolean	isForward() Check if the current propagation is forward or backward.
SpacecraftState	resetState(SpacecraftState oldState) Reset the state prior to continue propagation.
T	withHandler(EventHandler<? super T> newHandler) Setup the event handler to call at event occurrences.
T	withMaxCheck(double newMaxCheck) Setup the maximum checking interval.
T	withMaxIter(int newMaxIter) Setup the maximum number of iterations in the event time search.
T	withThreshold(double newThreshold) Setup the convergence threshold.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MAXCHECK

public static final double DEFAULT_MAXCHECK

Default maximum checking interval (s).

See Also:

Constant Field Values

DEFAULT_THRESHOLD

public static final double DEFAULT_THRESHOLD

Default convergence threshold (s).

See Also:

Constant Field Values

DEFAULT_MAX_ITER

public static final int DEFAULT_MAX_ITER

Default maximum number of iterations in the event time search.

See Also:

Constant Field Values

Constructor Detail

AbstractDetector

protected AbstractDetector(double maxCheck,
                           double threshold,
                           int maxIter,
                           EventHandler<? super T> handler)

Build a new instance.

Parameters:

maxCheck - maximum checking interval, must be strictly positive (s)

threshold - convergence threshold (s)

maxIter - maximum number of iterations in the event time search

handler - event handler to call at event occurrences

Method Detail

init

public void init(SpacecraftState s0,
                 AbsoluteDate t)

Initialize event handler at the start of a propagation.

This method is called once at the start of the propagation. It may be used by the event handler to initialize some internal data if needed.

The default implementation does nothing

This implementation sets the direction of propagation and initializes the event handler. If a subclass overrides this method it should call super.init(s0, t).

Specified by:

init in interface EventDetector

Parameters:

s0 - initial state

t - target time for the integration

g

public abstract 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.

Specified by:

g in interface EventDetector

Parameters:

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

Returns:

value of the switching function

getMaxCheckInterval

public double getMaxCheckInterval()

Get maximal time interval between switching function checks.

Specified by:

getMaxCheckInterval in interface EventDetector

Returns:

maximal time interval (s) between switching function checks

getMaxIterationCount

public int getMaxIterationCount()

Get maximal number of iterations in the event time search.

Specified by:

getMaxIterationCount in interface EventDetector

Returns:

maximal number of iterations in the event time search

getThreshold

public double getThreshold()

Get the convergence threshold in the event time search.

Specified by:

getThreshold in interface EventDetector

Returns:

convergence threshold (s)

withMaxCheck

public T withMaxCheck(double newMaxCheck)

Setup the maximum checking interval.

This will override a maximum checking interval if it has been configured previously.

Parameters:

newMaxCheck - maximum checking interval (s)

Returns:

a new detector with updated configuration (the instance is not changed)

Since:

6.1

withMaxIter

public T withMaxIter(int newMaxIter)

Setup the maximum number of iterations in the event time search.

This will override a number of iterations if it has been configured previously.

Parameters:

newMaxIter - maximum number of iterations in the event time search

Returns:

a new detector with updated configuration (the instance is not changed)

Since:

6.1

withThreshold

public T withThreshold(double newThreshold)

Setup the convergence threshold.

This will override a convergence threshold if it has been configured previously.

Parameters:

newThreshold - convergence threshold (s)

Returns:

a new detector with updated configuration (the instance is not changed)

Since:

6.1

withHandler

public T withHandler(EventHandler<? super T> newHandler)

Setup the event handler to call at event occurrences.

This will override a handler if it has been configured previously.

Parameters:

newHandler - event handler to call at event occurrences

Returns:

a new detector with updated configuration (the instance is not changed)

Since:

6.1

getHandler

public EventHandler<? super T> getHandler()

Get the handler.

Returns:

event handler to call at event occurrences

eventOccurred

public Action eventOccurred(SpacecraftState s,
                            boolean increasing)

Handle the event.

Specified by:

eventOccurred in interface EventDetector

Parameters:

s - SpaceCraft state to be used in the evaluation

increasing - with the event occurred in an "increasing" or "decreasing" slope direction

Returns:

the Action that the calling detector should pass back to the evaluation system

resetState

public SpacecraftState resetState(SpacecraftState oldState)

Reset the state prior to continue propagation.

This method is called after the step handler has returned and before the next step is started, but only when EventDetector.eventOccurred(org.orekit.propagation.SpacecraftState, boolean) has itself returned the Action.RESET_STATE indicator. It allows the user to reset the state for the next step, without perturbing the step handler of the finishing step. If the EventDetector.eventOccurred(org.orekit.propagation.SpacecraftState, boolean) never returns the Action.RESET_STATE indicator, this function will never be called, and it is safe to simply return null.

The default implementation simply returns its argument.

Specified by:

resetState in interface EventDetector

Parameters:

oldState - old state

Returns:

new state

create

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

Build a new instance.

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

isForward

public boolean isForward()

Check if the current propagation is forward or backward.

Returns:

true if the current propagation is forward

Since:

7.2