Package org.orekit.forces.maneuvers

Class ImpulseManeuver<T extends EventDetector>

  • Type Parameters:
    T - class type for the generic version
    All Implemented Interfaces:
    Serializable, EventDetector
    public class ImpulseManeuver<T extends EventDetector>
extends AbstractDetector<ImpulseManeuver<T>>
    Impulse maneuver model.

    This class implements an impulse maneuver as a discrete event that can be provided to any Propagator.

    The maneuver is triggered when an underlying event generates a STOP event, in which case this class will generate a RESET_STATE event (the stop event from the underlying object is therefore filtered out). In the simple cases, the underlying event detector may be a basic date event, but it can also be a more elaborate apside event for apogee maneuvers for example.

    The maneuver is defined by a single velocity increment in satellite frame. The current attitude of the spacecraft, defined by the current spacecraft state, will be used to compute the velocity direction in inertial frame. A typical case for tangential maneuvers is to use a LOF aligned attitude provider for state propagation and a velocity increment along the +X satellite axis.

    Beware that the triggering event detector must behave properly both before and after maneuver. If for example a node detector is used to trigger an inclination maneuver and the maneuver change the orbit to an equatorial one, the node detector will fail just after the maneuver, being unable to find a node on an equatorial orbit! This is a real case that has been encountered during validation ...

    Author:
    Luc Maisonobe
    See Also:
    Propagator.addEventDetector(EventDetector), Serialized Form

    • Constructor Detail

      • ImpulseManeuver

        public ImpulseManeuver​(T trigger,
                       org.hipparchus.geometry.euclidean.threed.Vector3D deltaVSat,
                       double isp)
        Build a new instance.
        Parameters:
        trigger - triggering event
        deltaVSat - velocity increment in satellite frame
        isp - engine specific impulse (s)

      • ImpulseManeuver

        public ImpulseManeuver​(T trigger,
                       AttitudeProvider attitudeOverride,
                       org.hipparchus.geometry.euclidean.threed.Vector3D deltaVSat,
                       double isp)
        Build a new instance.
        Parameters:
        trigger - triggering event
        attitudeOverride - the attitude provider to use for the maneuver
        deltaVSat - velocity increment in satellite frame
        isp - engine specific impulse (s)

    • Method Detail

      • create

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

      • init

        public void init​(SpacecraftState s0,
                 AbsoluteDate t)
        Initialize event handler at the start of a propagation.

        This method is called once at the start of the propagation. It may be used by the event handler to initialize some internal data if needed.

        The default implementation does nothing

        This implementation sets the direction of propagation and initializes the event handler. If a subclass overrides this method it should call super.init(s0, t).

        Specified by:
        init in interface EventDetector
        Overrides:
        init in class AbstractDetector<ImpulseManeuver<T extends EventDetector>>
        Parameters:
        s0 - initial state
        t - target time for the integration

      • g

        public double g​(SpacecraftState s)
        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<ImpulseManeuver<T extends EventDetector>>
        Parameters:
        s - the current state information: date, kinematics, attitude
        Returns:
        value of the switching function

      • getAttitudeOverride

        public AttitudeProvider getAttitudeOverride()
        Get the Attitude Provider to use during maneuver.
        Returns:
        the attitude provider

      • getTrigger

        public T getTrigger()
        Get the triggering event.
        Returns:
        triggering event

      • getDeltaVSat

        public org.hipparchus.geometry.euclidean.threed.Vector3D getDeltaVSat()
        Get the velocity increment in satellite frame.
        Returns:
        velocity increment in satellite frame

      • getIsp

        public double getIsp()
        Get the specific impulse.
        Returns:
        specific impulse