Class LongitudeCrossingDetector

    • Constructor Detail

      • LongitudeCrossingDetector

        public LongitudeCrossingDetector​(double maxCheck,
                                         double threshold,
                                         OneAxisEllipsoid body,
                                         double longitude)
        Build a detector.
        Parameters:
        maxCheck - maximal checking interval (s)
        threshold - convergence threshold (s)
        body - body on which the longitude is defined
        longitude - longitude to be crossed
    • Method Detail

      • create

        protected LongitudeCrossingDetector create​(double newMaxCheck,
                                                   double newThreshold,
                                                   int newMaxIter,
                                                   EventHandler<? super LongitudeCrossingDetector> newHandler)
        Build a new instance.
        Specified by:
        create in class AbstractDetector<LongitudeCrossingDetector>
        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
      • getBody

        public OneAxisEllipsoid getBody()
        Get the body on which the geographic zone is defined.
        Returns:
        body on which the geographic zone is defined
      • getLongitude

        public double getLongitude()
        Get the fixed longitude to be crossed (radians).
        Returns:
        fixed longitude to be crossed (radians)
      • g

        public double g​(SpacecraftState s)
        Compute the value of the detection function.

        The value is the longitude difference between the spacecraft and the fixed longitude to be crossed, with some sign tweaks to ensure continuity. These tweaks imply the increasing flag in events detection becomes irrelevant here! As an example, the longitude of a prograde spacecraft will always increase, but this g function will increase and decrease so it will cross the zero value once per orbit, in increasing and decreasing directions on alternate orbits. If eastwards and westwards crossing have to be distinguished, the velocity direction has to be checked instead of looking at the increasing flag.

        Specified by:
        g in interface EventDetector
        Specified by:
        g in class AbstractDetector<LongitudeCrossingDetector>
        Parameters:
        s - the current state information: date, kinematics, attitude
        Returns:
        longitude difference between the spacecraft and the fixed longitude, with some sign tweaks to ensure continuity