Package org.orekit.orbits

Class OrbitHermiteInterpolator

  • All Implemented Interfaces:
    TimeInterpolator<Orbit>
    public class OrbitHermiteInterpolator
extends AbstractOrbitInterpolator
    Class using a Hermite interpolator to interpolate orbits.

    Depending on given sample orbit type, the interpolation may differ :

    • For Keplerian, Circular and Equinoctial orbits, the interpolated instance is created by polynomial Hermite interpolation, using derivatives when available.
    • For Cartesian orbits, the interpolated instance is created using the cartesian derivatives filter given at instance construction. Hence, it will fall back to Lagrange interpolation if this instance has been designed to not use derivatives.

    In any case, it should be used only with small number of interpolation points (about 10-20 points) in order to avoid Runge's phenomenon and numerical problems (including NaN appearing).

    Author:
    Luc Maisonobe, Vincent Cucchietti
    See Also:
    Orbit, HermiteInterpolator

    • Constructor Detail

      • OrbitHermiteInterpolator

        public OrbitHermiteInterpolator​(Frame outputInertialFrame)
        Constructor with :
        • Default number of interpolation points of DEFAULT_INTERPOLATION_POINTS
        • Default extrapolation threshold value (DEFAULT_EXTRAPOLATION_THRESHOLD_SEC s)
        • Use of position and two time derivatives during interpolation
        As this implementation of interpolation is polynomial, it should be used only with small number of interpolation points (about 10-20 points) in order to avoid Runge's phenomenon and numerical problems (including NaN appearing).
        Parameters:
        outputInertialFrame - output inertial frame

      • OrbitHermiteInterpolator

        public OrbitHermiteInterpolator​(int interpolationPoints,
                                Frame outputInertialFrame)
        Constructor with :
        • Default extrapolation threshold value (DEFAULT_EXTRAPOLATION_THRESHOLD_SEC s)
        • Use of position and two time derivatives during interpolation
        As this implementation of interpolation is polynomial, it should be used only with small number of interpolation points (about 10-20 points) in order to avoid Runge's phenomenon and numerical problems (including NaN appearing).
        Parameters:
        interpolationPoints - number of interpolation points
        outputInertialFrame - output inertial frame

      • OrbitHermiteInterpolator

        public OrbitHermiteInterpolator​(int interpolationPoints,
                                Frame outputInertialFrame,
                                CartesianDerivativesFilter pvaFilter)
        Constructor with default extrapolation threshold value (DEFAULT_EXTRAPOLATION_THRESHOLD_SEC s).

        As this implementation of interpolation is polynomial, it should be used only with small number of interpolation points (about 10-20 points) in order to avoid Runge's phenomenon and numerical problems (including NaN appearing).

        Parameters:
        interpolationPoints - number of interpolation points
        outputInertialFrame - output inertial frame
        pvaFilter - filter for derivatives from the sample to use in position-velocity-acceleration interpolation. Used only when interpolating Cartesian orbits.

      • OrbitHermiteInterpolator

        public OrbitHermiteInterpolator​(int interpolationPoints,
                                double extrapolationThreshold,
                                Frame outputInertialFrame,
                                CartesianDerivativesFilter pvaFilter)
        Constructor.

        As this implementation of interpolation is polynomial, it should be used only with small number of interpolation points (about 10-20 points) in order to avoid Runge's phenomenon and numerical problems (including NaN appearing).

        Parameters:
        interpolationPoints - number of interpolation points
        extrapolationThreshold - extrapolation threshold beyond which the propagation will fail
        outputInertialFrame - output inertial frame
        pvaFilter - filter for derivatives from the sample to use in position-velocity-acceleration interpolation. Used only when interpolating Cartesian orbits.

    • Method Detail

      • getPVAFilter

        public CartesianDerivativesFilter getPVAFilter()
        Get filter for derivatives from the sample to use in position-velocity-acceleration interpolation.
        Returns:
        filter for derivatives from the sample to use in position-velocity-acceleration interpolation

      • interpolate

        protected Orbit interpolate​(AbstractTimeInterpolator.InterpolationData interpolationData)
        Interpolate instance from given interpolation data.

        Depending on given sample orbit type, the interpolation may differ :

        • For Keplerian, Circular and Equinoctial orbits, the interpolated instance is created by polynomial Hermite interpolation, using derivatives when available.
        • For Cartesian orbits, the interpolated instance is created using the cartesian derivatives filter given at instance construction. Hence, it will fall back to Lagrange interpolation if this instance has been designed to not use derivatives.
        If orbit interpolation on large samples is needed, using the Ephemeris class is a better way than using this low-level interpolation. The Ephemeris class automatically handles selection of a neighboring sub-sample with a predefined number of point from a large global sample in a thread-safe way.
        Specified by:
        interpolate in class AbstractTimeInterpolator<Orbit>
        Parameters:
        interpolationData - interpolation data
        Returns:
        interpolated instance at given date