fr.cnes.sirius.patrius.propagation.events

Class ApsideDetector

java.lang.Object

fr.cnes.sirius.patrius.propagation.events.AbstractDetector

fr.cnes.sirius.patrius.propagation.events.ApsideDetector

All Implemented Interfaces:

EventDetector, Serializable

public class ApsideDetector
extends AbstractDetector

Finder for apside crossing events.

This class finds apside crossing events (i.e. apogee and/or perigee crossing).

The default implementation behavior is to stop propagation at apogee or/and perigee crossing depending on slope selection defined PERIGEE, APOGEE and PERIGEE_APOGEE. This can be changed by overriding one of the following constructors :

• ApsideDetector : the defined action is performed at apogee OR/AND perigee depending on slope selection defined.
• ApsideDetector : the defined actions are performed at apogee AND perigee.

Beware that apside detection will fail for almost circular orbits.

Author:

Luc Maisonobe

See Also:

Propagator.addEventDetector(EventDetector), Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface fr.cnes.sirius.patrius.propagation.events.EventDetector

EventDetector.Action

Field Summary

Fields

Modifier and Type	Field and Description
static int	APOGEE Flag for apogee detection (slopeSelection = 1).
static int	PERIGEE Flag for perigee detection (slopeSelection = 0).
static int	PERIGEE_APOGEE Flag for both perigee and apogee detection (slopeSelection = 2).

Fields inherited from class fr.cnes.sirius.patrius.propagation.events.AbstractDetector

DEFAULT_MAXCHECK

Fields inherited from interface fr.cnes.sirius.patrius.propagation.events.EventDetector

DECREASING, INCREASING, INCREASING_DECREASING

Constructor Summary

Constructors

Constructor and Description
ApsideDetector(double maxCheck, double threshold, EventDetector.Action actionApogee, EventDetector.Action actionPerigee) Build a new instance with both apogee and perigee detection.
ApsideDetector(double maxCheck, double threshold, EventDetector.Action actionApogee, EventDetector.Action actionPerigee, boolean removeApogee, boolean removePerigee) Build a new instance with both apogee and perigee detection.
ApsideDetector(int slopeSelection, double maxCheck, double threshold) Build a new instance.
ApsideDetector(int slopeSelection, double maxCheck, double threshold, EventDetector.Action action) Build a new instance with apogee OR/AND perigee detection depending on slope selection.
ApsideDetector(int slopeSelection, double maxCheck, double threshold, EventDetector.Action action, boolean remove) Build a new instance with apogee OR/AND perigee detection depending on slope selection.
ApsideDetector(Orbit orbit, int slopeSelection) Build a new instance.
ApsideDetector(Orbit orbit, int slopeSelection, double threshold) Build a new instance.

Method Summary

Modifier and Type	Method and Description
EventDetector	copy() A copy of the detector.
EventDetector.Action	eventOccurred(SpacecraftState s, boolean increasing, boolean forward) Handle an apside crossing event and choose what to do next.
double	g(SpacecraftState s) Compute the value of the switching function.
EventDetector.Action	getActionAtApogee() Returns action at apogee detection.
EventDetector.Action	getActionAtPerigee() Returns action at perigee detection.
boolean	removeAtApogee() Returns true if detection is removed after apogee detection.
boolean	removeAtPerigee() Returns true if detection is removed after perigee detection.
boolean	shouldBeRemoved() This method is called after EventDetector.eventOccurred(fr.cnes.sirius.patrius.propagation.SpacecraftState, boolean, boolean) has been triggered.

Methods inherited from class fr.cnes.sirius.patrius.propagation.events.AbstractDetector

getMaxCheckInterval, getMaxIterationCount, getSlopeSelection, getThreshold, init, resetState

Methods inherited from class java.lang.Object

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

Field Detail

PERIGEE

public static final int PERIGEE

Flag for perigee detection (slopeSelection = 0).

See Also:

Constant Field Values

APOGEE

public static final int APOGEE

Flag for apogee detection (slopeSelection = 1).

See Also:

Constant Field Values

PERIGEE_APOGEE

public static final int PERIGEE_APOGEE

Flag for both perigee and apogee detection (slopeSelection = 2).

See Also:

Constant Field Values

Constructor Detail

ApsideDetector

public ApsideDetector(Orbit orbit,
                      int slopeSelection)

Build a new instance.

The orbit is used only to set an upper bound for the max check interval to period/3 and to set the convergence threshold according to orbit size

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

Parameters:

orbit - initial orbit

slopeSelection -
PERIGEE for perigee detection,
APOGEE for apogee detection,
PERIGEE_APOGEE for both perigee and apogee detection.

ApsideDetector

public ApsideDetector(Orbit orbit,
                      int slopeSelection,
                      double threshold)

Build a new instance.

The orbit is used only to set an upper bound for the max check interval to period/3

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

Parameters:

orbit - initial orbit

slopeSelection -
PERIGEE for perigee detection,
APOGEE for apogee detection,
PERIGEE_APOGEE for both perigee and apogee detection.

threshold - convergence threshold (s)

ApsideDetector

public ApsideDetector(int slopeSelection,
                      double maxCheck,
                      double threshold)

Build a new instance.

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

Parameters:

slopeSelection -
PERIGEE for perigee detection,
APOGEE for apogee detection,
PERIGEE_APOGEE for both perigee and apogee detection.

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

ApsideDetector

public ApsideDetector(double maxCheck,
                      double threshold,
                      EventDetector.Action actionApogee,
                      EventDetector.Action actionPerigee)

Build a new instance with both apogee and perigee detection.

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

actionApogee - action to be perform when the apogee is reached

actionPerigee - action to be perform when the perigee is reached

ApsideDetector

public ApsideDetector(double maxCheck,
                      double threshold,
                      EventDetector.Action actionApogee,
                      EventDetector.Action actionPerigee,
                      boolean removeApogee,
                      boolean removePerigee)

Build a new instance with both apogee and perigee detection.

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

actionApogee - action to be perform when the apogee is reached

actionPerigee - action to be perform when the perigee is reached

removeApogee - true if detector should be removed at apogee

removePerigee - true if detector should be removed at perigee

Since:

3.1

ApsideDetector

public ApsideDetector(int slopeSelection,
                      double maxCheck,
                      double threshold,
                      EventDetector.Action action)

Build a new instance with apogee OR/AND perigee detection depending on slope selection.

Parameters:

slopeSelection -
PERIGEE for perigee detection,
APOGEE for apogee detection,
PERIGEE_APOGEE for both perigee and apogee detection.

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

action - action to be performed when the expected apside is reached

ApsideDetector

public ApsideDetector(int slopeSelection,
                      double maxCheck,
                      double threshold,
                      EventDetector.Action action,
                      boolean remove)

Build a new instance with apogee OR/AND perigee detection depending on slope selection.

Parameters:

slopeSelection -
PERIGEE for perigee detection,
APOGEE for apogee detection,
PERIGEE_APOGEE for both perigee and apogee detection.

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

action - action to be performed when the expected apside is reached

remove - true if detector should be removed

Method Detail

getActionAtPerigee

public EventDetector.Action getActionAtPerigee()

Returns action at perigee detection.

Returns:

action at perigee detection

getActionAtApogee

public EventDetector.Action getActionAtApogee()

Returns action at apogee detection.

Returns:

action at apogee detection

removeAtPerigee

public boolean removeAtPerigee()

Returns true if detection is removed after perigee detection.

Returns:

true if detection is removed after perigee detection

removeAtApogee

public boolean removeAtApogee()

Returns true if detection is removed after apogee detection.

Returns:

true if detection is removed after apogee detection

shouldBeRemoved

public boolean shouldBeRemoved()

This method is called after EventDetector.eventOccurred(fr.cnes.sirius.patrius.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 PatriusException

Handle an apside crossing event and choose what to do next.

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

Throws:

PatriusException - if some specific error occurs

g

public double g(SpacecraftState s)
         throws PatriusException

Compute the value of the switching function. This function computes the dot product of the 2 vectors : position.velocity.

Specified by:

g in interface EventDetector

Specified by:

g in class AbstractDetector

Parameters:

s - the current state information: date, kinematics, attitude

Returns:

value of the switching function

Throws:

PatriusException - if some specific error occurs

copy

public EventDetector copy()

A copy of the detector. By default copy is deep. If not, detector javadoc will specify which attribute is not fully copied. In that case, the attribute reference is passed.

Returns:

a copy of the detector.