org.orekit.propagation.events
Class ExtremaLatitudeDetector

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

All Implemented Interfaces:

Serializable, EventDetector

public class ExtremaLatitudeDetector
extends AbstractDetector

Detects when the spacecraft reaches the maximal or minimal local latitude. The local minimum or maximum is chosen through a constructor parameter, with values MIN, MAX and MIN_MAX for both.

The default implementation behaviour is to stop propagation when the minimum/maximum latitude is reached. This can be changed by using provided constructors.

Since:

1.1

Version:

$Id: ExtremaLatitudeDetector.java 14677 2015-11-25 14:52:39Z rodrigues $

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

static int	MAX Flag for local maximum latitude detection (g decreasing).
static int	MIN Flag for local minimum latitude detection (g increasing).
static int	MIN_MAX Flag for both local minimum and maximum distance detection.

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

ExtremaLatitudeDetector(int extremumType, Frame bodyFrame)
Constructor for a ExtremaLatitudeDetector instance.

ExtremaLatitudeDetector(int extremumType, Frame bodyFrame, double maxCheck, double threshold)
Constructor for a ExtremaLatitudeDetector instance.

ExtremaLatitudeDetector(int extremumType, Frame bodyFrame, double maxCheck, double threshold, EventDetector.Action action)
Constructor for a ExtremaLatitudeDetector instance.

ExtremaLatitudeDetector(int extremumType, Frame bodyFrame, double maxCheck, double threshold, EventDetector.Action action, boolean remove)
Constructor for a ExtremaLatitudeDetector instance.

Method Summary

EventDetector.Action	eventOccurred(SpacecraftState s, boolean increasing, boolean forward) Handle an extrema latitude event and choose what to do next.
double	g(SpacecraftState s) Compute the value of the switching function.
Frame	getBodyFrame() Returns the body frame.
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

Field Detail

MIN

public static final int MIN

Flag for local minimum latitude detection (g increasing).

See Also:

Constant Field Values

MAX

public static final int MAX

Flag for local maximum latitude detection (g decreasing).

See Also:

Constant Field Values

MIN_MAX

public static final int MIN_MAX

Flag for both local minimum and maximum distance detection.

See Also:

Constant Field Values

Constructor Detail

ExtremaLatitudeDetector

public ExtremaLatitudeDetector(int extremumType,
                               Frame bodyFrame)

Constructor for a ExtremaLatitudeDetector instance.

Parameters:

extremumType - MIN for minimal latitude detection, MAX for maximal latitude detection or MIN_MAX for both minimal and maximal latitude detection

bodyFrame - the body attached frame (in witch the latitude is defined)

ExtremaLatitudeDetector

public ExtremaLatitudeDetector(int extremumType,
                               Frame bodyFrame,
                               double maxCheck,
                               double threshold)

Constructor for a ExtremaLatitudeDetector instance.

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

Parameters:

extremumType - MIN for minimal latitude detection, MAX for maximal latitude detection or MIN_MAX for both minimal and maximal latitude detection

bodyFrame - the body attached frame (in witch the latitude is defined)

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

ExtremaLatitudeDetector

public ExtremaLatitudeDetector(int extremumType,
                               Frame bodyFrame,
                               double maxCheck,
                               double threshold,
                               EventDetector.Action action)

Constructor for a ExtremaLatitudeDetector instance.

Parameters:

extremumType - MIN for minimal latitude detection, MAX for maximal latitude detection or MIN_MAX for both minimal and maximal latitude detection

bodyFrame - the body attached frame (in witch the latitude is defined)

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at extrema latitude detection

ExtremaLatitudeDetector

public ExtremaLatitudeDetector(int extremumType,
                               Frame bodyFrame,
                               double maxCheck,
                               double threshold,
                               EventDetector.Action action,
                               boolean remove)

Constructor for a ExtremaLatitudeDetector instance.

Parameters:

extremumType - MIN for minimal latitude detection, MAX for maximal latitude detection or MIN_MAX for both minimal and maximal latitude detection

bodyFrame - the body attached frame (in witch the latitude is defined)

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at extrema latitude detection

remove - true if detector should be removed at extrema latitude detection

Since:

3.1

Method Detail

eventOccurred

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

Handle an extrema latitude 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 expected extrema latitude is reached

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

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

getBodyFrame

public Frame getBodyFrame()

Returns the body frame.

Returns:

the body frame