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

Class Chan1997

java.lang.Object
org.orekit.ssa.collision.shorttermencounter.probability.twod.AbstractShortTermEncounter2DPOCMethod
org.orekit.ssa.collision.shorttermencounter.probability.twod.Chan1997
All Implemented Interfaces:
ShortTermEncounter2DPOCMethod
public class Chan1997 extends AbstractShortTermEncounter2DPOCMethod
Compute the probability of collision using the method described in :
"Chan, K. “Collision Probability Analyses for Earth Orbiting Satellites.” In Space Cooperation into the 21st Century: 7th AAS/JRS/CSA Symposium, International Space Conference of Pacific-Basin Societies (ISCOPS; formerly PISSTA) (July 15-18, 1997, Nagasaki, Japan), edited by Peter M. Bainum, et al., 1033-1048. Advances in the Astronautical Sciences Series 96. San Diego, California: Univelt, 1997. (Zeroth order analytical expression).

This method is also described in depth in : "CHAN, F. Kenneth, et al. Spacecraft collision probability. El Segundo, CA : Aerospace Press, 2008."

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.
  • Approximate ellipse by a disk
Since:
12.0
Author:
Vincent Cucchietti

  • Constructor Details

    • Chan1997

      public Chan1997()
      Empty constructor.

  • Method Details

    • 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

    • getType

      public ShortTermEncounter2DPOCMethodType getType()
      Get type of the method.
      Returns:
      type of the method