Class AbstractMatricesHarvester

    • Field Detail


        public static final int STATE_DIMENSION
        State dimension, fixed to 6.
        See Also:
        Constant Field Values
    • Constructor Detail

      • AbstractMatricesHarvester

        protected AbstractMatricesHarvester​(String stmName,
                                            RealMatrix initialStm,
                                            DoubleArrayDictionary initialJacobianColumns)
        Simple constructor.

        The arguments for initial matrices must be compatible with the orbit type and position angle that will be used by propagator

        stmName - State Transition Matrix state name
        initialStm - initial State Transition Matrix ∂Y/∂Y₀, if null (which is the most frequent case), assumed to be 6x6 identity
        initialJacobianColumns - initial columns of the Jacobians matrix with respect to parameters, if null or if some selected parameters are missing from the dictionary, the corresponding initial column is assumed to be 0
    • Method Detail

      • getStmName

        public String getStmName()
        Get the State Transition Matrix state name.
        State Transition Matrix state name
      • getInitialStateTransitionMatrix

        public RealMatrix getInitialStateTransitionMatrix()
        Get the initial State Transition Matrix.
        initial State Transition Matrix
      • getInitialJacobianColumn

        public double[] getInitialJacobianColumn​(String columnName)
        Get the initial column of Jacobian matrix with respect to named parameter.
        columnName - name of the column
        initial column of the Jacobian matrix
      • getConversionJacobian

        protected double[][] getConversionJacobian​(SpacecraftState state)
        Get the conversion Jacobian between state parameters and parameters used for derivatives.

        The base implementation returns identity, which is suitable for DSST and TLE propagators, as state parameters and parameters used for derivatives are the same.

        For Numerical propagator, parameters used for derivatives are Cartesian and they can be different from state parameters because the numerical propagator can accept different type of orbits, so the method is overridden in derived classes.

        state - spacecraft state
        conversion Jacobian
      • setReferenceState

        public void setReferenceState​(SpacecraftState reference)
        Set up reference state.

        This method is called whenever the global propagation reference state changes. This corresponds to the start of propagation in batch least squares orbit determination or at prediction step for each measurement in Kalman filtering. Its goal is to allow the harvester to compute some internal data. Analytical models like TLE use it to compute analytical derivatives, semi-analytical models like DSST use it to compute short periodic terms, numerical models do not use it at all.

        Specified by:
        setReferenceState in interface MatricesHarvester
        reference - reference state to set
      • getStateTransitionMatrix

        public RealMatrix getStateTransitionMatrix​(SpacecraftState state)
        Extract state transition matrix from state.
        Specified by:
        getStateTransitionMatrix in interface MatricesHarvester
        state - spacecraft state
        state transition matrix, with semantics consistent with propagation, or null if no state transition matrix is available orbit type.
      • getParametersJacobian

        public RealMatrix getParametersJacobian​(SpacecraftState state)
        Get the Jacobian with respect to propagation parameters.
        Specified by:
        getParametersJacobian in interface MatricesHarvester
        state - spacecraft state
        Jacobian with respect to propagation parameters, or null if there are no parameters
      • freezeColumnsNames

        public abstract void freezeColumnsNames()
        Freeze the names of the Jacobian columns.

        This method is called when propagation starts, i.e. when configuration is completed