Package org.orekit.propagation.events

Class AngularSeparationFromSatelliteDetector

java.lang.Object

org.orekit.propagation.events.AbstractDetector<AngularSeparationFromSatelliteDetector>

org.orekit.propagation.events.AngularSeparationFromSatelliteDetector

All Implemented Interfaces:

EventDetector

public class AngularSeparationFromSatelliteDetector
extends AbstractDetector<AngularSeparationFromSatelliteDetector>

Detects when two moving objects come close to each other, as seen from spacecraft.

The main use case for this detector is when the primary object is in fact a ground station, modeled as a TopocentricFrame and when the secondary is the Sun, for computing optical reflections.

The default handler behavior is to stop propagation when objects enter the proximity zone. This can be changed by calling AbstractDetector.withHandler(EventHandler) after construction.

Since:

11.0

Author:

Luc Maisonobe, Thomas Paulet

See Also:

Propagator.addEventDetector(EventDetector)

Field Summary

Fields inherited from class org.orekit.propagation.events.AbstractDetector

DEFAULT_MAX_ITER, DEFAULT_MAXCHECK, DEFAULT_THRESHOLD

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AngularSeparationFromSatelliteDetector(AdaptableInterval maxCheck, double threshold, int maxIter, EventHandler handler, PVCoordinatesProvider primaryObject, PVCoordinatesProvider secondaryObject, double proximityAngle)	Protected constructor with full parameters.
	AngularSeparationFromSatelliteDetector(PVCoordinatesProvider primaryObject, PVCoordinatesProvider secondaryObject, double proximityAngle)	Build a new angular detachment detector.

Method Summary

Modifier and Type	Method	Description
protected AngularSeparationFromSatelliteDetector	create(AdaptableInterval newMaxCheck, double newThreshold, int newMaxIter, EventHandler newHandler)	Build a new instance.
double	g(SpacecraftState s)	Compute the value of the switching function.
PVCoordinatesProvider	getPrimaryObject()	Get the primaryObject, at the center of the proximity zone.
double	getProximityAngle()	Get the proximity angle (rad).
PVCoordinatesProvider	getSecondaryObject()	Get the secondaryObject.

Methods inherited from class org.orekit.propagation.events.AbstractDetector

create, getDetectionSettings, getHandler, getMaxCheckInterval, getMaxIterationCount, getThreshold, init, isForward, withDetectionSettings, withHandler, withMaxCheck, withMaxCheck, withMaxIter, withThreshold

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.propagation.events.EventDetector

finish

Constructor Detail

AngularSeparationFromSatelliteDetector

public AngularSeparationFromSatelliteDetector(PVCoordinatesProvider primaryObject,
                                              PVCoordinatesProvider secondaryObject,
                                              double proximityAngle)

Build a new angular detachment detector.

Parameters:

primaryObject - primaryObject, at the center of the proximity zone

secondaryObject - secondaryObject, that may come close to the primaryObject as seen from the spacecraft

proximityAngle - proximity angle as seen from spacecraft, at which events are triggered (rad)

AngularSeparationFromSatelliteDetector

protected AngularSeparationFromSatelliteDetector(AdaptableInterval maxCheck,
                                                 double threshold,
                                                 int maxIter,
                                                 EventHandler handler,
                                                 PVCoordinatesProvider primaryObject,
                                                 PVCoordinatesProvider secondaryObject,
                                                 double proximityAngle)

Protected constructor with full parameters.

This constructor is not public as users are expected to use the builder API with the various withXxx() methods to set up the instance in a readable manner without using a huge amount of parameters.

Parameters:

maxCheck - maximum checking interval

threshold - convergence threshold (s)

maxIter - maximum number of iterations in the event time search

handler - event handler to call at event occurrences

primaryObject - primaryObject at the center of the proximity zone

secondaryObject - secondaryObject, that may come close to the primaryObject as seen from the spacecraft

proximityAngle - proximity angle as seen from secondaryObject, at which events are triggered (rad)

Method Detail

create

protected AngularSeparationFromSatelliteDetector create(AdaptableInterval newMaxCheck,
                                                        double newThreshold,
                                                        int newMaxIter,
                                                        EventHandler newHandler)

Build a new instance.

Specified by:

create in class AbstractDetector<AngularSeparationFromSatelliteDetector>

Parameters:

newMaxCheck - maximum checking interval (s)

newThreshold - convergence threshold (s)

newMaxIter - maximum number of iterations in the event time search

newHandler - event handler to call at event occurrences

Returns:

a new instance of the appropriate sub-type

getPrimaryObject

public PVCoordinatesProvider getPrimaryObject()

Get the primaryObject, at the center of the proximity zone.

Returns:

primaryObject

getSecondaryObject

public PVCoordinatesProvider getSecondaryObject()

Get the secondaryObject.

Returns:

secondaryObject

getProximityAngle

public double getProximityAngle()

Get the proximity angle (rad).

Returns:

the proximity angle

g

public double g(SpacecraftState s)

Compute the value of the switching function.

This function measures the angular separation between primary and secondary objects as seen from the spacecraft minus the proximity angle. It therefore triggers decreasing events when the secondary object enters the proximity zone and increasing events when it leaves the proximity zone.

No shadowing effect is taken into account, so this method is computed and may trigger events even when the secondary object is behind the primary. If such effects must be taken into account the detector must be associated with a predicate filter where the predicate function is based on eclipse conditions.

Parameters:

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

Returns:

value of the switching function