Class LambdaMethod
- java.lang.Object
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- org.orekit.estimation.measurements.gnss.AbstractLambdaMethod
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- org.orekit.estimation.measurements.gnss.LambdaMethod
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- All Implemented Interfaces:
IntegerLeastSquareSolver
- Direct Known Subclasses:
IntegerBootstrapping
public class LambdaMethod extends AbstractLambdaMethod
Decorrelation/reduction engine for LAMBDA method.This class implements PJG Teunissen Least Square Ambiguity Decorrelation Adjustment (LAMBDA) method, as described in both the 1996 paper The LAMBDA method for integer ambiguity estimation: implementation aspects by Paul de Jonge and Christian Tiberius and on the 2005 paper A modified LAMBDA method for integer least-squares estimation by X.-W Chang, X. Yang and T. Zhou, Journal of Geodesy 79(9):552-565, DOI: 10.1007/s00190-005-0004-x
It slightly departs on the original LAMBDA method as it does implement the following improvements proposed in the de Jonge and Tiberius 1996 paper that vastly speed up the search:
- alternate search starting from the middle and expanding outwards
- automatic shrinking of ellipsoid during the search
- Since:
- 10.0
- Author:
- Luc Maisonobe
- See Also:
AmbiguitySolver
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Constructor Summary
Constructors Constructor Description LambdaMethod()
Empty constructor.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected void
discreteSearch()
Find the best solutions to the Integer Least Square problem.protected void
inverseDecomposition()
Inverse the decomposition.protected void
ltdlDecomposition()
Perform Lᵀ.D.L = Q decomposition of the covariance matrix.protected void
reduction()
Perform LAMBDA reduction.-
Methods inherited from class org.orekit.estimation.measurements.gnss.AbstractLambdaMethod
addSolution, getDecorrelatedReference, getDiagReference, getLowReference, getMaxDistance, getMaxSolution, getSize, getSolutionsSize, getZInverseTransformationReference, integerGaussTransformation, lIndex, permutation, recoverAmbiguities, removeSolution, setComparator, solveILS, zIndex
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Method Detail
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ltdlDecomposition
protected void ltdlDecomposition()
Perform Lᵀ.D.L = Q decomposition of the covariance matrix.- Specified by:
ltdlDecomposition
in classAbstractLambdaMethod
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reduction
protected void reduction()
Perform LAMBDA reduction.- Specified by:
reduction
in classAbstractLambdaMethod
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discreteSearch
protected void discreteSearch()
Find the best solutions to the Integer Least Square problem.- Specified by:
discreteSearch
in classAbstractLambdaMethod
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inverseDecomposition
protected void inverseDecomposition()
Inverse the decomposition.This method transforms the Lᵀ.D.L = Q decomposition of covariance into the L⁻¹.D⁻¹.L⁻ᵀ = Q⁻¹ decomposition of the inverse of covariance.
- Specified by:
inverseDecomposition
in classAbstractLambdaMethod
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