org.orekit.propagation.events
Class BetaAngleDetector

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

All Implemented Interfaces:

Serializable, EventDetector

public class BetaAngleDetector
extends AbstractDetector

Detects when the beta angle of the spacecraft reaches a predetermined value.
The beta angle is the angle between the orbit plane and the vector from the central body to the sun. The angle is positive on the side of the plane containing the spacecraft's momentum vector. The bodies considered are :

• the spacecraft
• the central body for the spacecraft
• the Sun

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

Since:

1.1

Version:

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

Author:

cardosop

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

BetaAngleDetector(double ang)
Constructor for a BetaAngleDetector instance.

BetaAngleDetector(double ang, double maxCheck, double threshold)
Constructor for a BetaAngleDetector instance with complimentary parameters.

BetaAngleDetector(double ang, double maxCheck, double threshold, EventDetector.Action action)
Constructor for a BetaAngleDetector instance with complimentary parameters.

BetaAngleDetector(double ang, double maxCheck, double threshold, EventDetector.Action action, boolean remove)
Constructor for a BetaAngleDetector instance with complimentary parameters.

Method Summary

EventDetector.Action	eventOccurred(SpacecraftState s, boolean increasing, boolean forward) Handles a beta angle event and chooses what to do next.
double	g(SpacecraftState s) Compute the value of the switching function.
double	getAngle() Returns beta angle triggering the event.
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

BetaAngleDetector

public BetaAngleDetector(double ang)

Constructor for a BetaAngleDetector instance.

Parameters:

ang - angle in radians triggering the event.

BetaAngleDetector

public BetaAngleDetector(double ang,
                         double maxCheck,
                         double threshold)

Constructor for a BetaAngleDetector instance with complimentary parameters.

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

Parameters:

ang - angle in radians triggering the event.

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

Throws:

IllegalArgumentException - if angle is out of range [-Pi / 2 , Pi / 2]

BetaAngleDetector

public BetaAngleDetector(double ang,
                         double maxCheck,
                         double threshold,
                         EventDetector.Action action)

Constructor for a BetaAngleDetector instance with complimentary parameters.

Parameters:

ang - angle in radians triggering the event.

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at beta angle detection

Throws:

IllegalArgumentException - if angle is out of range [-Pi / 2 , Pi / 2]

BetaAngleDetector

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

Constructor for a BetaAngleDetector instance with complimentary parameters.

Parameters:

ang - angle in radians triggering the event.

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at beta angle detection

remove - if the detector should be removed

Throws:

IllegalArgumentException - if angle is out of range [-Pi / 2 , Pi / 2]

Since:

3.1

Method Detail

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

eventOccurred

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

Handles a beta angle event and chooses 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 time increases around event.

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

Returns:

performed the action when the 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

getAngle

public double getAngle()

Returns beta angle triggering the event.

Returns:

the Angle triggering the event.