fr.cnes.sirius.patrius.events.detectors

Class AltitudeDetector

java.lang.Object

fr.cnes.sirius.patrius.events.AbstractDetector

fr.cnes.sirius.patrius.events.detectors.AltitudeDetector

All Implemented Interfaces:

EventDetector, Serializable

public class AltitudeDetector
extends AbstractDetector

Finder for satellite altitude crossing events.

This class finds altitude events (i.e. satellite crossing a predefined altitude level above ground).

The default implementation behavior is to continue propagation when ascending and to stop propagation when descending. This can be changed by using provided constructors.

This class is restricted to be used with EllipsoidBodyShape.

Author:

Luc Maisonobe

See Also:

Propagator.addEventDetector(EventDetector), Serialized Form

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
static int	ASCENDING Flag for ascending altitude detection (slopeSelection = 0).
static int	ASCENDING_DESCENDING Flag for both ascending and descending altitude detection (slopeSelection = 2).
static int	DESCENDING Flag for descending altitude detection (slopeSelection = 1).

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

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

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

DECREASING, INCREASING, INCREASING_DECREASING

Constructor Summary

Constructors

Constructor and Description
AltitudeDetector(double altitudeIn, EllipsoidBodyShape bodyShapeIn) Build a new altitude detector.
AltitudeDetector(double altitudeIn, EllipsoidBodyShape bodyShapeIn, double maxCheck, double threshold) Build a new altitude detector.
AltitudeDetector(double altitudeIn, EllipsoidBodyShape bodyShapeIn, double maxCheck, double threshold, EventDetector.Action ascending, EventDetector.Action descending) Build a new altitude detector.
AltitudeDetector(double altitudeIn, EllipsoidBodyShape bodyShapeIn, double maxCheck, double threshold, EventDetector.Action ascending, EventDetector.Action descending, boolean removeAscending, boolean removeDescending) Build a new altitude detector.
AltitudeDetector(double altitudeIn, EllipsoidBodyShape bodyShapeIn, 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 an altitude event and choose what to do next.
double	g(SpacecraftState state) Compute the value of the switching function.
double	getAltitude() Getter for the threshold altitude value.
BodyShape	getBodyShape() Getter for the body shape.

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

ASCENDING

public static final int ASCENDING

Flag for ascending altitude detection (slopeSelection = 0).

See Also:

Constant Field Values

DESCENDING

public static final int DESCENDING

Flag for descending altitude detection (slopeSelection = 1).

See Also:

Constant Field Values

ASCENDING_DESCENDING

public static final int ASCENDING_DESCENDING

Flag for both ascending and descending altitude detection (slopeSelection = 2).

See Also:

Constant Field Values

Constructor Detail

AltitudeDetector

public AltitudeDetector(double altitudeIn,
                        EllipsoidBodyShape bodyShapeIn)

Build a new altitude detector.

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 continue propagation when ascending and to stop propagation when descending.

Parameters:

altitudeIn - threshold altitude value (m)

bodyShapeIn - body shape with respect to which altitude should be evaluated

AltitudeDetector

public AltitudeDetector(double altitudeIn,
                        EllipsoidBodyShape bodyShapeIn,
                        double maxCheck,
                        double threshold)

Build a new altitude detector.

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.

The default implementation behavior is to continue propagation when ascending and to stop propagation when descending.

Parameters:

altitudeIn - threshold altitude value (m)

bodyShapeIn - body shape with respect to which altitude should be evaluated

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

AltitudeDetector

public AltitudeDetector(double altitudeIn,
                        EllipsoidBodyShape bodyShapeIn,
                        double maxCheck,
                        double threshold,
                        EventDetector.Action ascending,
                        EventDetector.Action descending)

Build a new altitude detector.

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:

altitudeIn - threshold altitude value (m)

bodyShapeIn - body shape with respect to which altitude should be evaluated

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

ascending - action performed when ascending

descending - action performed when descending

AltitudeDetector

public AltitudeDetector(double altitudeIn,
                        EllipsoidBodyShape bodyShapeIn,
                        double maxCheck,
                        double threshold,
                        EventDetector.Action ascending,
                        EventDetector.Action descending,
                        boolean removeAscending,
                        boolean removeDescending)

Build a new altitude detector.

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:

altitudeIn - threshold altitude value (m)

bodyShapeIn - body shape with respect to which altitude should be evaluated

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

ascending - action performed when ascending

descending - action performed when descending

removeAscending - true if detector should be removed at ascending altitude detection

removeDescending - true if detector should be removed at descending altitude detection

Since:

3.1

AltitudeDetector

public AltitudeDetector(double altitudeIn,
                        EllipsoidBodyShape bodyShapeIn,
                        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:

altitudeIn - threshold altitude value (m)

bodyShapeIn - body shape with respect to which altitude should be evaluated

slopeSelection - slope selection

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

action - action performed

remove - true if detector should be removed at altitude detection

Since:

3.1

Method Detail

getAltitude

public double getAltitude()

Getter for the threshold altitude value.

Returns:

the threshold altitude value (m)

getBodyShape

public BodyShape getBodyShape()

Getter for the body shape.

Returns:

the body shape

eventOccurred

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

Handle an altitude 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 times increases around event

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

Returns:

the action performed when altitude 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 measures the difference between the current altitude and the threshold altitude.

Specified by:

g in interface EventDetector

Specified by:

g in class AbstractDetector

Parameters:

state - state

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.

The following attributes are not deeply copied:

• bodyShape: BodyShape

Returns:

a copy of the detector.