org.orekit.propagation.events
Class DateDetector

java.lang.Object
  org.orekit.propagation.events.AbstractDetector
      org.orekit.propagation.events.DateDetector

All Implemented Interfaces:

Serializable, EventDetector, TimeStamped

public class DateDetector
extends AbstractDetector
implements TimeStamped

Finder for date events.

This class finds date events (i.e. occurrence of some predefined dates).

As of version 5.1, it is an enhanced date detector:

• it can be defined without prior date (DateDetector(double,double))
• several dates can be added (addEventDate(AbsoluteDate))

The gap between the added dates must be more than the maxCheck.

The default implementation behavior is to stop propagation at the first event date occurrence. This can be changed by using provided constructors.

Author:

Luc Maisonobe, Pascal Parraud

See Also:

Propagator.addEventDetector(EventDetector), Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.orekit.propagation.events.EventDetector

EventDetector.Action

Field Summary

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

DEFAULT_MAXCHECK, DEFAULT_THRESHOLD

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

DECREASING, INCREASING, INCREASING_DECREASING

Constructor Summary

DateDetector(AbsoluteDate target)
Build a new instance.

DateDetector(AbsoluteDate target, double maxCheck, double threshold)
Build a new instance.

DateDetector(AbsoluteDate target, double maxCheck, double threshold, EventDetector.Action action)
Build a new instance.

DateDetector(AbsoluteDate target, double maxCheck, double threshold, EventDetector.Action action, boolean remove)
Build a new instance.

DateDetector(double maxCheck, double threshold)
Build a new instance.

DateDetector(double maxCheck, double threshold, EventDetector.Action action)
Build a new instance.

DateDetector(double maxCheck, double threshold, EventDetector.Action action, boolean remove)
Build a new instance.

Method Summary

void	addEventDate(AbsoluteDate target) Add an event date.
EventDetector.Action	eventOccurred(SpacecraftState s, boolean increasing, boolean forward) Handle a date event and choose what to do next.
double	g(SpacecraftState s) Compute the value of the switching function.
AbsoluteDate	getDate() Get the current event date according to the propagator.
boolean	shouldBeRemoved() This method is called after EventDetector.eventOccurred(org.orekit.propagation.SpacecraftState, boolean, boolean) has been triggered.

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

getMaxCheckInterval, getMaxIterationCount, getSlopeSelection, getThreshold, init, resetState

Methods inherited from class java.lang.Object

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

Constructor Detail

DateDetector

public DateDetector(double maxCheck,
                    double threshold)

Build a new instance.

This constructor is dedicated to date detection when the event date is not known before propagating. It can be triggered later by adding some event date, it then acts like a timer.

The default implementation behavior is to stop propagation at date occurrence.

Parameters:

maxCheck - maximum checking interval (s)

threshold - convergence threshold (s)

See Also:

addEventDate(AbsoluteDate)

DateDetector

public DateDetector(double maxCheck,
                    double threshold,
                    EventDetector.Action action)

Build a new instance.

This constructor is dedicated to date detection when the event date is not known before propagating. It can be triggered later by adding some event date, it then acts like a timer.

Parameters:

maxCheck - maximum checking interval (s)

threshold - convergence threshold (s)

action - action performed at date detection

See Also:

addEventDate(AbsoluteDate)

DateDetector

public DateDetector(double maxCheck,
                    double threshold,
                    EventDetector.Action action,
                    boolean remove)

Build a new instance.

This constructor is dedicated to date detection when the event date is not known before propagating. It can be triggered later by adding some event date, it then acts like a timer.

Parameters:

maxCheck - maximum checking interval (s)

threshold - convergence threshold (s)

action - action performed at date detection

remove - true if detector should be removed after first detection

See Also:

addEventDate(AbsoluteDate)

DateDetector

public DateDetector(AbsoluteDate target,
                    double maxCheck,
                    double threshold)

Build a new instance.

First event date is set here, but others can be added later with addEventDate(AbsoluteDate).

The default implementation behavior is to stop propagation at date occurrence.

Parameters:

target - target date

maxCheck - maximum checking interval (s)

threshold - convergence threshold (s)

See Also:

addEventDate(AbsoluteDate)

DateDetector

public DateDetector(AbsoluteDate target,
                    double maxCheck,
                    double threshold,
                    EventDetector.Action action)

Build a new instance.

First event date is set here, but others can be added later with addEventDate(AbsoluteDate).

Parameters:

target - target date

maxCheck - maximum checking interval (s)

threshold - convergence threshold (s)

action - action performed at date detection

See Also:

addEventDate(AbsoluteDate)

DateDetector

public DateDetector(AbsoluteDate target,
                    double maxCheck,
                    double threshold,
                    EventDetector.Action action,
                    boolean remove)

Build a new instance.

First event date is set here, but others can be added later with addEventDate(AbsoluteDate).

Parameters:

target - target date

maxCheck - maximum checking interval (s)

threshold - convergence threshold (s)

action - action performed at date detection

remove - true if detector should be removed after first detection

Since:

3.1

See Also:

addEventDate(AbsoluteDate)

DateDetector

public DateDetector(AbsoluteDate target)

Build a new instance.

This constructor is dedicated to single date detection. MaxCheck is set to 10.e9, so almost no other date can be added. Tolerance is set to 10.e-10.

Parameters:

target - target date

See Also:

addEventDate(AbsoluteDate)

Method Detail

eventOccurred

public EventDetector.Action eventOccurred(SpacecraftState s,
                                          boolean increasing,
                                          boolean forward)
                                   throws OrekitException

Handle a date event and choose what to do next.

Specified by:

eventOccurred in interface EventDetector

Specified by:

eventOccurred in class AbstractDetector

Parameters:

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

increasing - the way of the switching function is not guaranted as it can change according to the added event dates

forward - if true, the integration variable (time) increases during integration.

Returns:

the action performed at the first event date occurrence.

Throws:

OrekitException - if some specific error occurs

shouldBeRemoved

public boolean shouldBeRemoved()

This method is called after EventDetector.eventOccurred(org.orekit.propagation.SpacecraftState, boolean, boolean) has been triggered. It returns true if the current detector should be removed after first event detection. WARNING: this method can be called only once a event has been triggered. Before, the value is not available.

Specified by:

shouldBeRemoved in interface EventDetector

Specified by:

shouldBeRemoved in class AbstractDetector

Returns:

true if the current detector should be removed after first event detection

g

public double g(SpacecraftState s)
         throws OrekitException

Compute the value of the switching function. This function measures the difference between the current and the target date.

Specified by:

g in interface EventDetector

Specified by:

g in class AbstractDetector

Parameters:

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

Returns:

value of the switching function

Throws:

OrekitException - if some specific error occurs

getDate

public AbsoluteDate getDate()

Get the current event date according to the propagator.

Specified by:

getDate in interface TimeStamped

Returns:

event date

addEventDate

public void addEventDate(AbsoluteDate target)
                  throws IllegalArgumentException

Add an event date.

The date to add must be:

• less than the smallest already registered event date minus the maxCheck
• or more than the largest already registered event date plus the maxCheck

Parameters:

target - target date

Throws:

IllegalArgumentException - if the date is too close from already defined interval

See Also:

DateDetector(double, double)