org.orekit.propagation.events
Class AOLDetector

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

All Implemented Interfaces:

Serializable, EventDetector

public class AOLDetector
extends AbstractDetector

Detects when the Argument of Latitude of the spacecraft reaches a predetermined value, θ.
The Argument of Latitude is not defined for all kinds of orbits: this detector will detect an event only if the corresponding orbit is not an equatorial orbit, otherwise it may trigger events randomly.

The default implementation behaviour is to stop propagation when the angle θ is reached. This can be changed by using provided constructors.

Since:

1.1

Version:

$Id: AOLDetector.java 17582 2017-05-10 12:58:16Z bignon $

Author:

Tiziana Sabatini

See Also:

EventDetector, Serialized Form

Concurrency :

not thread-safe

Concurrency comment :

attributes are mutable and related to propagation.

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

AOLDetector(double angle, PositionAngle type, Frame equator)
Constructor for an AOLDetector instance.

AOLDetector(double angle, PositionAngle type, Frame equator, double maxCheck, double threshold)
Constructor for an AOLDetector instance with complementary parameters.

AOLDetector(double angle, PositionAngle type, Frame equator, double maxCheck, double threshold, EventDetector.Action action)
Constructor for an AOLDetector instance with complementary parameters.

AOLDetector(double angle, PositionAngle type, Frame equator, double maxCheck, double threshold, EventDetector.Action action, boolean remove)
Constructor for an AOLDetector instance with complementary parameters.

Method Summary

EventDetector.Action	eventOccurred(SpacecraftState s, boolean increasing, boolean forward) Handle an AOL event and choose what to do next.
double	g(SpacecraftState s) Compute the value of the switching function.
double	getAOL() Get the AOL to detect.
Frame	getAOLFrame() Get the reference frame.
PositionAngle	getAOLType() Get the type of AOL to detect.
void	init(SpacecraftState s0, AbsoluteDate t) Initialize event handler at the start of a propagation.
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, resetState

Methods inherited from class java.lang.Object

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

Constructor Detail

AOLDetector

public AOLDetector(double angle,
                   PositionAngle type,
                   Frame equator)

Constructor for an AOLDetector instance.

Parameters:

angle - AOL value triggering the event.

type - type of AOL to detect, one of TRUE, MEAN and ECCENTRIC.

equator - equator with respect to which the AOL is to be computed

See Also:

PositionAngle

AOLDetector

public AOLDetector(double angle,
                   PositionAngle type,
                   Frame equator,
                   double maxCheck,
                   double threshold)

Constructor for an AOLDetector instance with complementary parameters.

The default implementation behaviour is to stop propagation when the AOL angle is reached.

Parameters:

angle - AOL value triggering the event.

type - type of AOL to detect, one of TRUE, MEAN and ECCENTRIC.

equator - equator with respect to which the AOL is to be computed

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

AOLDetector

public AOLDetector(double angle,
                   PositionAngle type,
                   Frame equator,
                   double maxCheck,
                   double threshold,
                   EventDetector.Action action)

Constructor for an AOLDetector instance with complementary parameters.

Parameters:

angle - AOL value triggering the event.

type - type of AOL to detect, one of TRUE, MEAN and ECCENTRIC.

equator - equator with respect to which the AOL is to be computed

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at AOL detection

AOLDetector

public AOLDetector(double angle,
                   PositionAngle type,
                   Frame equator,
                   double maxCheck,
                   double threshold,
                   EventDetector.Action action,
                   boolean remove)

Constructor for an AOLDetector instance with complementary parameters.

Parameters:

angle - AOL value triggering the event.

type - type of AOL to detect, one of TRUE, MEAN and ECCENTRIC.

equator - equator with respect to which the AOL is to be computed

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at AOL detection

remove - true if detector should be removed

Since:

3.1

Method Detail

shouldBeRemoved

public boolean shouldBeRemoved()

Description copied from class: AbstractDetector

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

eventOccurred

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

Handle an AOL 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 - if true, the value of the switching function increases when times increases around event

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

Returns:

the action performed when when the AOL angle is reached.

Throws:

OrekitException - if some specific error occurs

g

public double g(SpacecraftState s)
         throws OrekitException

Description copied from class: AbstractDetector

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

Specified by:

g in class AbstractDetector

Parameters:

s - the current state information: date, kinematics, attitude for forces and events computation, mass provider, and additional states

Returns:

value of the switching function

Throws:

OrekitException - if some specific error occurs

init

public void init(SpacecraftState s0,
                 AbsoluteDate t)

Description copied from class: AbstractDetector

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.

Specified by:

init in interface EventDetector

Overrides:

init in class AbstractDetector

Parameters:

s0 - initial state

t - target time for the integration

getAOL

public double getAOL()

Get the AOL to detect.

Returns:

the angle triggering the event.

getAOLType

public PositionAngle getAOLType()

Get the type of AOL to detect.

Returns:

the type of angle triggering the event

getAOLFrame

public Frame getAOLFrame()

Get the reference frame.

Returns:

the reference frame to compute AOL