Package org.orekit.propagation.events

Class EclipseDetector

  • All Implemented Interfaces:
    EventDetector
    public class EclipseDetector
extends AbstractDetector<EclipseDetector>
    Finder for satellite eclipse related events.

    This class finds eclipse events, i.e. satellite within umbra (total eclipse) or penumbra (partial eclipse).

    The occulted body is given through a PVCoordinatesProvider and its radius in meters. It is modeled as a sphere.

    Since v10.0 the occulting body is a OneAxisEllipsoid, before it was modeled as a sphere.
    It was changed to precisely model Solar eclipses by the Earth, especially for Low Earth Orbits.
    If you want eclipses by a spherical occulting body, set its flattening to 0. when defining its OneAxisEllipsoid model..

    The withUmbra() or withPenumbra() methods will tell you if the event is triggered when complete umbra/lighting is achieved or when entering/living the penumbra zone.
    The default behavior is detecting complete umbra/lighting events.
    If you want to have both, you'll need to set up two distinct detectors.

    The default implementation behavior is to continue propagation when entering the eclipse and to stop propagation when exiting the eclipse.
    This can be changed by calling AbstractDetector.withHandler(EventHandler) after construction.

    Author:
    Pascal Parraud, Luc Maisonobe
    See Also:
    Propagator.addEventDetector(EventDetector)

    • Constructor Detail

      • EclipseDetector

        protected EclipseDetector​(AdaptableInterval maxCheck,
                          double threshold,
                          int maxIter,
                          EventHandler handler,
                          OccultationEngine occultationEngine,
                          double margin,
                          boolean totalEclipse)
        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
        occultationEngine - occultation engine
        margin - to apply to eclipse angle (rad)
        totalEclipse - umbra (true) or penumbra (false) detection flag
        Since:
        12.0

    • Method Detail

      • create

        protected EclipseDetector create​(AdaptableInterval newMaxCheck,
                                 double newThreshold,
                                 int nawMaxIter,
                                 EventHandler newHandler)
        Build a new instance.
        Specified by:
        create in class AbstractDetector<EclipseDetector>
        Parameters:
        newMaxCheck - maximum checking interval (s)
        newThreshold - convergence threshold (s)
        nawMaxIter - 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

      • withUmbra

        public EclipseDetector withUmbra()
        Setup the detector to full umbra detection.

        This will override a penumbra/umbra flag if it has been configured previously.

        Returns:
        a new detector with updated configuration (the instance is not changed)
        Since:
        6.1
        See Also:
        withPenumbra()

      • withPenumbra

        public EclipseDetector withPenumbra()
        Setup the detector to penumbra detection.

        This will override a penumbra/umbra flag if it has been configured previously.

        Returns:
        a new detector with updated configuration (the instance is not changed)
        Since:
        6.1
        See Also:
        withUmbra()

      • withMargin

        public EclipseDetector withMargin​(double newMargin)
        Setup a margin to angle detection.

        A positive margin implies eclipses are "larger" hence entry occurs earlier and exit occurs later than a detector with 0 margin.

        Parameters:
        newMargin - angular margin to apply to eclipse detection (rad)
        Returns:
        a new detector with updated configuration (the instance is not changed)
        Since:
        12.0

      • getMargin

        public double getMargin()
        Get the angular margin used for eclipse detection.
        Returns:
        angular margin used for eclipse detection (rad)
        Since:
        12.0

      • getOccultationEngine

        public OccultationEngine getOccultationEngine()
        Get the occultation engine.
        Returns:
        occultation engine
        Since:
        12.0

      • getTotalEclipse

        public boolean getTotalEclipse()
        Get the total eclipse detection flag.
        Returns:
        the total eclipse detection flag (true for umbra events detection, false for penumbra events detection)

      • g

        public double g​(SpacecraftState s)
        Compute the value of the switching function. This function becomes negative when entering the region of shadow and positive when exiting.
        Specified by:
        g in interface EventDetector
        Specified by:
        g in class AbstractDetector<EclipseDetector>
        Parameters:
        s - the current state information: date, kinematics, attitude
        Returns:
        value of the switching function