org.orekit.propagation.events
Class AnomalyDetector

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

All Implemented Interfaces:

Serializable, EventDetector

public class AnomalyDetector
extends AbstractDetector

Detects when the anomaly of the spacecraft reaches a predetermined value, θ.
Anomaly is not defined for all kinds of orbits: this detector will detect anomaly events only if the corresponding orbit is not a circular orbit, otherwise it may trigger events randomly.

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

This detector is unusable on a circular orbit where the perigee always moves very fast and in any way. This detector detects only anomaly going in a growing way.

Since:

1.1

Version:

$Id: AnomalyDetector.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

AnomalyDetector(PositionAngle angleType, double angle)
Constructor for an AnomalyDetector instance.

AnomalyDetector(PositionAngle angleType, double angle, double maxCheck, double threshold)
Constructor for an AnomalyDetector instance with complementary parameters.

AnomalyDetector(PositionAngle angleType, double angle, double maxCheck, double threshold, EventDetector.Action action)
Constructor for an AnomalyDetector instance with complementary parameters.

AnomalyDetector(PositionAngle angleType, double angle, double maxCheck, double threshold, EventDetector.Action action, boolean remove)
Constructor for an AnomalyDetector instance with complementary parameters.

Method Summary

EventDetector.Action	eventOccurred(SpacecraftState s, boolean increasing, boolean forward) Handle an anomaly event and choose what to do next.
double	g(SpacecraftState s) Compute the value of the switching function.
double	getAnomaly() Get the anomaly to detect.
PositionAngle	getAnomalyType() Get the type of anomaly 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

AnomalyDetector

public AnomalyDetector(PositionAngle angleType,
                       double angle)

Constructor for an AnomalyDetector instance.

Parameters:

angleType - true, eccentric or mean anomaly.

angle - anomaly value triggering the event.

AnomalyDetector

public AnomalyDetector(PositionAngle angleType,
                       double angle,
                       double maxCheck,
                       double threshold)

Constructor for an AnomalyDetector instance with complementary parameters.

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

Parameters:

angleType - true, eccentric or mean anomaly.

angle - anomaly value triggering the event.

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

AnomalyDetector

public AnomalyDetector(PositionAngle angleType,
                       double angle,
                       double maxCheck,
                       double threshold,
                       EventDetector.Action action)

Constructor for an AnomalyDetector instance with complementary parameters.

Parameters:

angleType - true, eccentric or mean anomaly.

angle - anomaly value triggering the event.

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at anomaly detection

AnomalyDetector

public AnomalyDetector(PositionAngle angleType,
                       double angle,
                       double maxCheck,
                       double threshold,
                       EventDetector.Action action,
                       boolean remove)

Constructor for an AnomalyDetector instance with complementary parameters.

Parameters:

angleType - true, eccentric or mean anomaly.

angle - anomaly value triggering the event.

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at anomaly detection

remove - if detector should be removed

Since:

3.1

Method Detail

eventOccurred

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

Handle an anomaly 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 the anomaly is reached

Throws:

OrekitException - if some specific error occurs

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

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

getAnomaly

public double getAnomaly()

Get the anomaly to detect.

Returns:

the anomaly triggering the event.

getAnomalyType

public PositionAngle getAnomalyType()

Get the type of anomaly to detect.

Returns:

the anomaly type