Class Alfriend1999Max
- java.lang.Object
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- org.orekit.ssa.collision.shorttermencounter.probability.twod.AbstractShortTermEncounter2DPOCMethod
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- org.orekit.ssa.collision.shorttermencounter.probability.twod.AbstractAlfriend1999
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- org.orekit.ssa.collision.shorttermencounter.probability.twod.Alfriend1999Max
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- All Implemented Interfaces:
ShortTermEncounter2DPOCMethod
public class Alfriend1999Max extends AbstractAlfriend1999
Compute the probability of collision assuming the worst case described in : "Kyle Alfriend, Maruthi Akella, Joseph Frisbee, James Foster, Deok-Jin Lee, and Matthew Wilkins. Probability of ProbabilityOfCollision Error Analysis. Space Debris, 1(1):21–35, 1999.".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.
- Both objects are in circular orbits (eq 14).
- Probability density function is constant over the collision circle (eq 18).
- Covariance multiplied by a coefficient KSquared = MahalanobisDistanceSquared / 2 (eq 19-20).
By assuming a constant probability density function over the collision circle this method will, most of the time, give much higher probability of collision than other regular methods. That is why it is qualified as a maximum probability of collision computing method.
- Since:
- 12.0
- Author:
- Vincent Cucchietti
- See Also:
- Mahalanobis distance.
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Field Summary
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Fields inherited from class org.orekit.ssa.collision.shorttermencounter.probability.twod.AbstractShortTermEncounter2DPOCMethod
DEFAULT_TCA_DIFFERENCE_TOLERANCE
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Fields inherited from interface org.orekit.ssa.collision.shorttermencounter.probability.twod.ShortTermEncounter2DPOCMethod
DEFAULT_ZERO_THRESHOLD
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Constructor Summary
Constructors Constructor Description Alfriend1999Max()
Empty constructor.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description double
computeValue(double radius, double squaredMahalanobisDistance, double covarianceMatrixDeterminant)
Compute the value of the probability of collision.<T extends CalculusFieldElement<T>>
TcomputeValue(T radius, T squaredMahalanobisDistance, T covarianceMatrixDeterminant)
Compute the value of the probability of collision.ShortTermEncounter2DPOCMethodType
getType()
Get type of the method.boolean
isAMaximumProbabilityOfCollisionMethod()
Get flag that defines if the method is a maximum probability of collision computing method.-
Methods inherited from class org.orekit.ssa.collision.shorttermencounter.probability.twod.AbstractAlfriend1999
compute, compute
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Methods inherited from class org.orekit.ssa.collision.shorttermencounter.probability.twod.AbstractShortTermEncounter2DPOCMethod
compute, compute, compute, compute, compute, compute, getName, getObjectOrbitFromCdm, getObjectStateCovarianceFromCdm
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Method Detail
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computeValue
public double computeValue(double radius, double squaredMahalanobisDistance, double covarianceMatrixDeterminant)
Compute the value of the probability of collision.- Parameters:
radius
- sum of primary and secondary collision object equivalent sphere radii (m)squaredMahalanobisDistance
- squared Mahalanobis distancecovarianceMatrixDeterminant
- covariance matrix determinant- Returns:
- value of the probability of collision
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computeValue
public <T extends CalculusFieldElement<T>> T computeValue(T radius, T squaredMahalanobisDistance, T covarianceMatrixDeterminant)
Compute the value of the probability of collision.- Type Parameters:
T
- type of the field elements- Parameters:
radius
- sum of primary and secondary collision object equivalent sphere radii (m)squaredMahalanobisDistance
- squared Mahalanobis distancecovarianceMatrixDeterminant
- covariance matrix determinant- Returns:
- value of the probability of collision
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isAMaximumProbabilityOfCollisionMethod
public boolean isAMaximumProbabilityOfCollisionMethod()
Get flag that defines if the method is a maximum probability of collision computing method.- Specified by:
isAMaximumProbabilityOfCollisionMethod
in interfaceShortTermEncounter2DPOCMethod
- Overrides:
isAMaximumProbabilityOfCollisionMethod
in classAbstractShortTermEncounter2DPOCMethod
- Returns:
- flag that defines if the method is a maximum probability of collision computing method
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getType
public ShortTermEncounter2DPOCMethodType getType()
Get type of the method.- Returns:
- type of the method
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