fr.cnes.sirius.patrius.events.detectors

Class DistanceDetector

java.lang.Object

fr.cnes.sirius.patrius.events.AbstractDetector

fr.cnes.sirius.patrius.events.detectors.DistanceDetector

All Implemented Interfaces:

EventDetector, Serializable

Direct Known Subclasses:

SurfaceDistanceDetector

public class DistanceDetector
extends AbstractDetector

Detects when the distance from the spacecraft to a given body reaches a predetermined value.

The default implementation behaviour is to EventDetector.Action#STOP stop propagation when the distance is reached. This can be changed by using provided constructors.

Since:

1.1

Version:

$Id: DistanceDetector.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 fr.cnes.sirius.patrius.events.EventDetector

EventDetector.Action

Field Summary

Fields

Modifier and Type	Field and Description
protected PVCoordinatesProvider	body Distant body.
static int	DECREASING Flag for decreasing distance detection (slopeSelection = 1).
protected double	distance Distance triggering the event.
static int	INCREASING Flag for increasing distance detection (slopeSelection = 0).
static int	INCREASING_DECREASING Flag for both increasing and decreasing distance detection (slopeSelection = 2).

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

actionAtEntry, actionAtExit, DEFAULT_MAXCHECK, DEFAULT_MAXITER, DEFAULT_THRESHOLD, removeAtEntry, removeAtExit, shouldBeRemovedFlag

Constructor Summary

Constructors

Constructor and Description
DistanceDetector(PVCoordinatesProvider bodyIn, double distanceIn) Constructor for a DistanceDetector instance.
DistanceDetector(PVCoordinatesProvider bodyIn, double distanceIn, double maxCheck, double threshold) Constructor for a DistanceDetector instance with additional maxCheck and threshold parameters The default implementation behavior is to EventDetector.Action#STOP stop propagation when the distance is reached.
DistanceDetector(PVCoordinatesProvider bodyIn, double distanceIn, double maxCheck, double threshold, EventDetector.Action actionIncreasing, EventDetector.Action actionDecreasing) Constructor for a DistanceDetector instance with complimentary parameters.
DistanceDetector(PVCoordinatesProvider bodyIn, double distanceIn, double maxCheck, double threshold, EventDetector.Action actionIncreasing, EventDetector.Action actionDecreasing, boolean removeIncreasing, boolean removeDecreasing) Constructor for a DistanceDetector instance with complimentary parameters.
DistanceDetector(PVCoordinatesProvider bodyIn, double distanceIn, int slopeSelection, double maxCheck, double threshold, EventDetector.Action action, boolean remove) Build a new altitude detector with slope selection.

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 a distance event and choose what to do next.
double	g(SpacecraftState state) Compute the value of the switching function.
PVCoordinatesProvider	getBody() Returns the body whose distance is watched.
double	getDistance() Returns the distance triggering the event.

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

filterEvent, getActionAtEntry, getActionAtExit, getMaxCheckInterval, getMaxIterationCount, getSlopeSelection, getThreshold, init, isRemoveAtEntry, isRemoveAtExit, logEventsOverTimeInterval, resetState, setMaxCheckInterval, setMaxIter, shouldBeRemoved

Methods inherited from class java.lang.Object

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

Field Detail

INCREASING

public static final int INCREASING

Flag for increasing distance detection (slopeSelection = 0).

See Also:

Constant Field Values

DECREASING

public static final int DECREASING

Flag for decreasing distance detection (slopeSelection = 1).

See Also:

Constant Field Values

INCREASING_DECREASING

public static final int INCREASING_DECREASING

Flag for both increasing and decreasing distance detection (slopeSelection = 2).

See Also:

Constant Field Values

distance

protected final double distance

Distance triggering the event.

body

protected final PVCoordinatesProvider body

Distant body.

Constructor Detail

DistanceDetector

public DistanceDetector(PVCoordinatesProvider bodyIn,
                        double distanceIn)

Constructor for a DistanceDetector instance.

This simple constructor takes default values for maximal checking interval (AbstractDetector.DEFAULT_MAXCHECK) and convergence threshold (AbstractDetector.DEFAULT_THRESHOLD).

The default implementation behavior is to EventDetector.Action#STOP stop propagation when the distance is reached.

The distanceIn parameter must be positive.

Parameters:

bodyIn - The body whose distance is watched.

distanceIn - Distance triggering the event (m)

Throws:

IllegalArgumentException - when the distance is negative

DistanceDetector

public DistanceDetector(PVCoordinatesProvider bodyIn,
                        double distanceIn,
                        double maxCheck,
                        double threshold)

Constructor for a DistanceDetector instance with additional maxCheck and threshold parameters

The default implementation behavior is to EventDetector.Action#STOP stop propagation when the distance is reached.

Parameters:

bodyIn - The body whose distance is watched

distanceIn - Distance triggering the event (m)

maxCheck - Maximal checking interval (s)

threshold - Convergence threshold (s)

Throws:

IllegalArgumentException - when the distance is negative

DistanceDetector

public DistanceDetector(PVCoordinatesProvider bodyIn,
                        double distanceIn,
                        double maxCheck,
                        double threshold,
                        EventDetector.Action actionIncreasing,
                        EventDetector.Action actionDecreasing)

Constructor for a DistanceDetector instance with complimentary parameters.

Parameters:

bodyIn - The body whose distance is watched

distanceIn - Distance triggering the event (m)

maxCheck - Maximal checking interval (s)

threshold - Convergence threshold (s)

actionIncreasing - Action performed at distance detection when distance is increasing

actionDecreasing - Action performed at distance detection when distance is decreasing

Throws:

IllegalArgumentException - when the distance is negative

DistanceDetector

public DistanceDetector(PVCoordinatesProvider bodyIn,
                        double distanceIn,
                        double maxCheck,
                        double threshold,
                        EventDetector.Action actionIncreasing,
                        EventDetector.Action actionDecreasing,
                        boolean removeIncreasing,
                        boolean removeDecreasing)

Constructor for a DistanceDetector instance with complimentary parameters.

Parameters:

bodyIn - The body whose distance is watched

distanceIn - Distance triggering the event (m)

maxCheck - Maximal checking interval (s)

threshold - Convergence threshold (s)

actionIncreasing - Action performed at distance detection when distance is increasing

actionDecreasing - Action performed at distance detection when distance is decreasing

removeIncreasing - True if detector should be removed at increasing distance detection

removeDecreasing - True if detector should be removed at decreasing distance detection

Throws:

IllegalArgumentException - when the distance is negative

DistanceDetector

public DistanceDetector(PVCoordinatesProvider bodyIn,
                        double distanceIn,
                        int slopeSelection,
                        double maxCheck,
                        double threshold,
                        EventDetector.Action action,
                        boolean remove)

Build a new altitude detector with slope selection.

The maximal interval between altitude checks should be smaller than the half duration of the minimal pass to handle, otherwise some short passes could be missed.

Parameters:

bodyIn - The body whose distance is watched

distanceIn - Distance triggering the event (m)

slopeSelection - The g-function slope selection (0,1 or 2)

maxCheck - Maximal checking interval (s)

threshold - Convergence threshold (s)

action - Action performed at distance detection

remove - True if detector should be removed at distance detection

Method Detail

eventOccurred

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

Handle a distance event and choose what to do next.

Specified by:

eventOccurred in interface EventDetector

Overrides:

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:

the action performed when the expected distance is reached

Throws:

PatriusException - if some specific error occurs

g

public double g(SpacecraftState state)
         throws PatriusException

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:

state - the current state information: date, kinematics, attitude for forces and events computation, mass provider, and additional states

Returns:

value of the switching function

Throws:

PatriusException - if some specific error occurs

getDistance

public double getDistance()

Returns the distance triggering the event.

Returns:

the distance triggering the event (m)

getBody

public PVCoordinatesProvider getBody()

Returns the body whose distance is watched.

Returns:

the body whose distance is watched

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.

The following attributes are not deeply copied:

• body: PVCoordinatesProvider

Returns:

a copy of the detector.