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

Class Alfano2005

java.lang.Object

org.orekit.ssa.collision.shorttermencounter.probability.twod.AbstractShortTermEncounter2DPOCMethod

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

Field Summary

Fields inherited from class org.orekit.ssa.collision.shorttermencounter.probability.twod.AbstractShortTermEncounter2DPOCMethod

DEFAULT_TCA_DIFFERENCE_TOLERANCE

Fields inherited from interface org.orekit.ssa.collision.shorttermencounter.probability.twod.ShortTermEncounter2DPOCMethod

DEFAULT_ZERO_THRESHOLD

Constructor Summary

Constructors

Constructor	Description
Alfano2005()	Empty constructor.

Method Summary

Modifier and Type	Method	Description
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.
<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.
ShortTermEncounter2DPOCMethodType	getType()	Get type of the method.

Methods inherited from class org.orekit.ssa.collision.shorttermencounter.probability.twod.AbstractShortTermEncounter2DPOCMethod

compute, compute, compute, compute, compute, compute, getName, getObjectOrbitFromCdm, getObjectStateCovarianceFromCdm, isAMaximumProbabilityOfCollisionMethod

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.orekit.ssa.collision.shorttermencounter.probability.twod.ShortTermEncounter2DPOCMethod

compute, compute, compute, compute, compute, compute, compute, compute, compute

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.

Specified by:

compute in interface ShortTermEncounter2DPOCMethod

Specified by:

compute in class AbstractShortTermEncounter2DPOCMethod

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.

Specified by:

compute in interface ShortTermEncounter2DPOCMethod

Specified by:

compute in class AbstractShortTermEncounter2DPOCMethod

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