Package org.orekit.control.heuristics.lambert

Class LambertDifferentialCorrector

  • public class LambertDifferentialCorrector
extends Object
    Class implementing a differential correction for extended (meaning under arbitrary dynamics) Lambert arc (fixed initial and terminal position vectors with fixed time). Given boundary conditions and a guess, applies Newton-Raphson algorithm to find the solution (initial and terminal velocity vectors) according to the propagator used. The latter must be compatible with resetting the initial state and computing state transition matrices. Note that propagation is not required to be forward in time.
    Since:
    13.1
    Author:
    Romain Serra
    See Also:
    AbstractPropagator, LambertBoundaryConditions

    • Field Detail

      • DEFAULT_POSITION_TOLERANCE

        public static final double DEFAULT_POSITION_TOLERANCE
        Default value for convergence (on the position vector).
        See Also:
        Constant Field Values

      • DEFAULT_MAX_ITER

        public static final int DEFAULT_MAX_ITER
        Default maximum number of iterations.
        See Also:
        Constant Field Values

    • Constructor Detail

      • LambertDifferentialCorrector

        public LambertDifferentialCorrector​(LambertBoundaryConditions lambertBoundaryConditions)
        Constructor.
        Parameters:
        lambertBoundaryConditions - boundary conditions

    • Method Detail

      • getLambertBoundaryConditions

        public LambertBoundaryConditions getLambertBoundaryConditions()
        Getter for the boundary conditions.
        Returns:
        conditions

      • setInitialMass

        public void setInitialMass​(double initialMass)
        Setter for the initial mass.
        Parameters:
        initialMass - initial mass

      • getInitialMass

        public double getInitialMass()
        Getter for the initial mass.
        Returns:
        initial mass

      • getPositionTolerance

        public double getPositionTolerance()
        Getter for the position tolerance.
        Returns:
        tolerance

      • setPositionTolerance

        public void setPositionTolerance​(double positionTolerance)
        Setter for the position tolerance.
        Parameters:
        positionTolerance - tolerance

      • setThresholdMatrixSolver

        public void setThresholdMatrixSolver​(double thresholdMatrixSolver)
        Setter for the threshold used in linear system solving.
        Parameters:
        thresholdMatrixSolver - threshold

      • getThresholdMatrixSolver

        public double getThresholdMatrixSolver()
        Getter for the threshold used in linear system solving.
        Returns:
        threshold

      • setStmName

        public void setStmName​(String stmName)
        Setter for the state transition matrix name.
        Parameters:
        stmName - name

      • getStmName

        public String getStmName()
        Getter for the state transition matrix name.
        Returns:
        name

      • getMaxIter

        public int getMaxIter()
        Getter for the maximum number of iterations.
        Returns:
        maximum iterations

      • setMaxIter

        public void setMaxIter​(int maxIter)
        Setter for the maximum number of iterations.
        Parameters:
        maxIter - maximum iterations

      • setCurrentIter

        protected void setCurrentIter​(int currentIter)
        Protected setter for the current iteration number.
        Parameters:
        currentIter - iteration number

      • getCurrentIter

        public int getCurrentIter()
        Getter for the current iteration number.
        Returns:
        iteration number

      • getMatricesHarvester

        protected MatricesHarvester getMatricesHarvester()
        Protected getter for the state transition matrices harvester.
        Returns:
        harvester

      • getDecompositionSolver

        protected DecompositionSolver getDecompositionSolver​(RealMatrix matrix)
        Creates a linear system solver.
        Parameters:
        matrix - matrix involved in system
        Returns:
        solver

      • solve

        public LambertBoundaryVelocities solve​(AbstractPropagator propagator,
                                       Vector3D guessInitialVelocity)
        Method applying differential correction on the guess (Newton-Raphson algorithm).
        Parameters:
        propagator - propagator to be used for differential corrections
        guessInitialVelocity - guess on the initial velocity vector
        Returns:
        boundary velocities (null if not converged)

      • init

        protected void init​(AbstractPropagator propagator,
                    Vector3D guessInitialVelocity)
        Initialize propagator.
        Parameters:
        propagator - propagator to be used for differential corrections
        guessInitialVelocity - guess on the initial velocity vector

      • iterate

        protected LambertBoundaryVelocities iterate​(AbstractPropagator propagator)
        Apply differential corrections until convergence (interrupted by maximum iterations count).
        Parameters:
        propagator - propagator
        Returns:
        boundary velocities (null if not converged)

      • buildInitialState

        protected SpacecraftState buildInitialState​(AbstractPropagator propagator,
                                            SpacecraftState templateState,
                                            Vector3D initialVelocity)
        Method creating an initial state.
        Parameters:
        propagator - propagator
        templateState - template state
        initialVelocity - initial velocity to use
        Returns:
        full propagation state for initialization

      • computeNewtonCorrection

        protected Vector3D computeNewtonCorrection​(Vector3D positionDifference,
                                           RealMatrix cartesianStm)
        Method computing the Newton-Raphson correction.
        Parameters:
        positionDifference - position residuals
        cartesianStm - Cartesian state transition matrix
        Returns:
        correction

      • getCartesianStm

        protected RealMatrix getCartesianStm​(SpacecraftState initialState,
                                     SpacecraftState terminalState)
        Computes the state transition matrix in Cartesian coordinates.
        Parameters:
        initialState - initial state
        terminalState - terminal state
        Returns:
        Cartesian STM

      • hasConverged

        protected boolean hasConverged​(Vector3D positionDifference)
        Checks convergence.
        Parameters:
        positionDifference - position residuals
        Returns:
        convergence flag