org.orekit.propagation.events
Class LatitudeDetector

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

All Implemented Interfaces:

Serializable, EventDetector

public class LatitudeDetector
extends AbstractDetector

Detects when the spacecraft reaches a given local latitude.

The default implementation behavior is to stop propagation when the expected latitude is reached. This can be changed by overriding one of the following constructors :

• LatitudeDetector : the defined action is performed at latitude detection depending on slope type defined.
• LatitudeDetector : the defined actions are performed for local increasing AND decreasing latitude.

Since:

1.2

Version:

$Id: LatitudeDetector.java 14731 2015-11-30 13:44:04Z rodrigues $

Author:

Thomas Trapier

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	DOWN Flag for local decreasing latitude detection (g decreasing).
static int	UP Flag for local increasing latitude detection (g increasing).
static int	UP_DOWN Flag for both local increasing and decreasing latitude 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

LatitudeDetector(double latitudeToDetect, BodyShape earth, double maxCheck, double threshold, EventDetector.Action increasing, EventDetector.Action decreasing)
Constructor for the latitude detector for both local increasing and decreasing latitude.

LatitudeDetector(double latitudeToDetect, BodyShape earth, double maxCheck, double threshold, EventDetector.Action increasing, EventDetector.Action decreasing, boolean removeIncreasing, boolean removeDecreasing)
Constructor for the latitude detector for both local increasing and decreasing latitude.

LatitudeDetector(double latitudeToDetect, BodyShape earth, int slopeType)
Constructor for the latitude detector.

LatitudeDetector(double latitudeToDetect, BodyShape earth, int slopeType, double maxCheck, double threshold)
Constructor for the latitude detector.

LatitudeDetector(double latitudeToDetect, BodyShape earth, int slopeType, double maxCheck, double threshold, EventDetector.Action action)
Constructor for the latitude detector.

LatitudeDetector(double latitudeToDetect, BodyShape earth, int slopeType, double maxCheck, double threshold, EventDetector.Action action, boolean remove)
Constructor for the latitude detector.

Method Summary

EventDetector.Action	eventOccurred(SpacecraftState s, boolean increasing, boolean forward) Handle a latitude reaching event and choose what to do next.
double	g(SpacecraftState s) Compute the value of the switching function.
BodyShape	getEarthShape() Returns the Earth shape.
double	getLatitudeToDetect() Returns the latitude 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

Field Detail

UP

public static final int UP

Flag for local increasing latitude detection (g increasing).

See Also:

Constant Field Values

DOWN

public static final int DOWN

Flag for local decreasing latitude detection (g decreasing).

See Also:

Constant Field Values

UP_DOWN

public static final int UP_DOWN

Flag for both local increasing and decreasing latitude detection.

See Also:

Constant Field Values

Constructor Detail

LatitudeDetector

public LatitudeDetector(double latitudeToDetect,
                        BodyShape earth,
                        int slopeType)

Constructor for the latitude detector.

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

Parameters:

latitudeToDetect - the latitude to detect (must be between -PI/2 and PI/2)

earth - the earth shape

slopeType - UP for increasing latitude detection, DOWN for decreasing latitude detection or UP_DOWN for both increasing and decreasing latitude detection

LatitudeDetector

public LatitudeDetector(double latitudeToDetect,
                        BodyShape earth,
                        int slopeType,
                        double maxCheck,
                        double threshold)

Constructor for the latitude detector.

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

Parameters:

latitudeToDetect - the latitude to detect (must be between -PI/2 and PI/2)

earth - the earth shape

slopeType - UP for increasing latitude detection, DOWN for decreasing latitude detection or UP_DOWN for both increasing and decreasing latitude detection

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

LatitudeDetector

public LatitudeDetector(double latitudeToDetect,
                        BodyShape earth,
                        double maxCheck,
                        double threshold,
                        EventDetector.Action increasing,
                        EventDetector.Action decreasing)

Constructor for the latitude detector for both local increasing and decreasing latitude.

Parameters:

latitudeToDetect - the latitude to detect (must be between -PI/2 and PI/2)

earth - the earth shape

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

increasing - action performed at latitude detection when increasing

decreasing - action performed at latitude detection when decreasing

LatitudeDetector

public LatitudeDetector(double latitudeToDetect,
                        BodyShape earth,
                        double maxCheck,
                        double threshold,
                        EventDetector.Action increasing,
                        EventDetector.Action decreasing,
                        boolean removeIncreasing,
                        boolean removeDecreasing)

Constructor for the latitude detector for both local increasing and decreasing latitude.

Parameters:

latitudeToDetect - the latitude to detect (must be between -PI/2 and PI/2)

earth - the earth shape

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

increasing - action performed at latitude detection when increasing

decreasing - action performed at latitude detection when decreasing

removeIncreasing - true if detector should be removed at latitude detection when increasing

removeDecreasing - true if detector should be removed at latitude detection when decreasing

Since:

3.1

LatitudeDetector

public LatitudeDetector(double latitudeToDetect,
                        BodyShape earth,
                        int slopeType,
                        double maxCheck,
                        double threshold,
                        EventDetector.Action action)

Constructor for the latitude detector.

Parameters:

latitudeToDetect - the latitude to detect (must be between -PI/2 and PI/2)

earth - the earth shape

slopeType - UP for increasing latitude detection, DOWN for decreasing latitude detection or UP_DOWN for both increasing and decreasing latitude detection

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at latitude detection

LatitudeDetector

public LatitudeDetector(double latitudeToDetect,
                        BodyShape earth,
                        int slopeType,
                        double maxCheck,
                        double threshold,
                        EventDetector.Action action,
                        boolean remove)

Constructor for the latitude detector.

Parameters:

latitudeToDetect - the latitude to detect (must be between -PI/2 and PI/2)

earth - the earth shape

slopeType - UP for increasing latitude detection, DOWN for decreasing latitude detection or UP_DOWN for both increasing and decreasing latitude detection

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at latitude detection

remove - true if detector should be removed at latitude detection NB : If remove is true, it means detector should be removed at detection, so the value of attributes removeAtIncreasing and removeAtDecreasing must be decided according slopeType. Doing it, we ensure that detector will be removed well at propagation when calling method eventOccured (in which the value of attribute shouldBeRemoved is decided). In this case, users should better create an LatitudeDetector with constructor LatitudeDetector(double, BodyShape, double, double, EventDetector.Action, EventDetector.Action, boolean, boolean)

Since:

3.1

Method Detail

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

eventOccurred

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

Handle a latitude reaching event and choose what to do next.

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

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 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

getLatitudeToDetect

public double getLatitudeToDetect()

Returns the latitude to detect.

Returns:

the latitude to detect

getEarthShape

public BodyShape getEarthShape()

Returns the Earth shape.

Returns:

the earthShape