Package org.orekit.ssa.collision.shorttermencounter.probability.twod

Class Alfano2005

  • All Implemented Interfaces:
    ShortTermEncounter2DPOCMethod
    public class Alfano2005
extends AbstractShortTermEncounter2DPOCMethod
    Compute the probability of collision using the method described in :"S. Alfano. A numerical implementation of spherical objet collision probability. Journal of Astronautical Sciences, 53(1), January-March 2005."

    It assumes :

    • Short encounter leading to a linear relative motion.
    • Spherical collision object.
    • Uncorrelated positional covariance.
    • Gaussian distribution of the position uncertainties.
    • Deterministic velocity i.e. no velocity uncertainties.

    Also, it has been implemented using a simpson integration scheme as explained in his paper.

    Since:
    12.0
    Author:
    Vincent Cucchietti

    • Constructor Detail

      • Alfano2005

        public Alfano2005()
        Empty constructor.

    • Method Detail

      • compute

        public ProbabilityOfCollision compute​(double xm,
                                      double ym,
                                      double sigmaX,
                                      double sigmaY,
                                      double radius)
        Compute the probability of collision using arguments specific to the rotated encounter frame.

        The rotated encounter frame is define by the initial encounter frame (defined in ShortTermEncounter2DDefinition) rotated by the rotation matrix which is used to diagonalize the combined covariance matrix.

        Parameters:
        xm - other collision object projected position onto the collision plane in the rotated encounter frame x-axis (m)
        ym - other collision object projected position onto the collision plane in the rotated encounter frame y-axis (m)
        sigmaX - square root of the x-axis eigen value of the diagonalized combined covariance matrix projected onto the collision plane (m)
        sigmaY - square root of the y-axis eigen value of the diagonalized combined covariance matrix projected onto the collision plane (m)
        radius - sum of primary and secondary collision object equivalent sphere radii (m)
        Returns:
        probability of collision

      • compute

        public <T extends CalculusFieldElement<T>> FieldProbabilityOfCollision<T> compute​(T xm,
                                                                                  T ym,
                                                                                  T sigmaX,
                                                                                  T sigmaY,
                                                                                  T radius)
        Compute the probability of collision using arguments specific to the rotated encounter frame.

        The rotated encounter frame is define by the initial encounter frame (defined in ShortTermEncounter2DDefinition) rotated by the rotation matrix which is used to diagonalize the combined covariance matrix.

        Type Parameters:
        T - type of the field elements
        Parameters:
        xm - other collision object projected position onto the collision plane in the rotated encounter frame x-axis (m)
        ym - other collision object projected position onto the collision plane in the rotated encounter frame y-axis (m)
        sigmaX - square root of the x-axis eigen value of the diagonalized combined covariance matrix projected onto the collision plane (m)
        sigmaY - square root of the y-axis eigen value of the diagonalized combined covariance matrix projected onto the collision plane (m)
        radius - sum of primary and secondary collision object equivalent sphere radii (m)
        Returns:
        probability of collision