Package org.orekit.propagation.conversion

Class AbstractPropagatorConverter

java.lang.Object
org.orekit.propagation.conversion.AbstractPropagatorConverter
All Implemented Interfaces:
PropagatorConverter
Direct Known Subclasses:
FiniteDifferencePropagatorConverter, JacobianPropagatorConverter
public abstract class AbstractPropagatorConverter extends Object implements PropagatorConverter
Common handling of PropagatorConverter methods for propagators conversions.

This abstract class factors the common code for propagators conversion. Only one method must be implemented by derived classes: getObjectiveFunction().

The converter uses the LevenbergMarquardtOptimizer from the Hipparchus library. Different implementations correspond to different methods for computing the Jacobian.

Since:
6.0
Author:
Pascal Parraud

  • Constructor Details

    • AbstractPropagatorConverter

      protected AbstractPropagatorConverter(PropagatorBuilder builder, double threshold, int maxIterations)
      Build a new instance.
      Parameters:
      builder - propagator builder
      threshold - absolute convergence threshold for optimization algorithm
      maxIterations - maximum number of iterations for fitting

  • Method Details

    • convert

      public Propagator convert(Propagator source, double timeSpan, int nbPoints, List<String> freeParameters) throws IllegalArgumentException
      Convert a propagator to another.
      Specified by:
      convert in interface PropagatorConverter
      Parameters:
      source - initial propagator (the propagator will be used for sample generation, if it is a numerical propagator, its initial state will be reset unless AbstractIntegratedPropagator.setResetAtEnd(boolean) has been called beforehand)
      timeSpan - time span for fitting
      nbPoints - number of fitting points over time span
      freeParameters - names of the free parameters
      Returns:
      adapted propagator
      Throws:
      IllegalArgumentException - if one of the parameters cannot be free

    • convert

      public Propagator convert(Propagator source, double timeSpan, int nbPoints, String... freeParameters) throws IllegalArgumentException
      Convert a propagator to another.
      Specified by:
      convert in interface PropagatorConverter
      Parameters:
      source - initial propagator (the propagator will be used for sample generation, if it is a numerical propagator, its initial state will be reset unless AbstractIntegratedPropagator.setResetAtEnd(boolean) has been called beforehand)
      timeSpan - time span for fitting
      nbPoints - number of fitting points over time span
      freeParameters - names of the free parameters
      Returns:
      adapted propagator
      Throws:
      IllegalArgumentException - if one of the parameters cannot be free

    • convert

      public Propagator convert(List<SpacecraftState> states, boolean positionOnly, List<String> freeParameters) throws IllegalArgumentException
      Find the propagator that minimize the mean square error for a sample of states.
      Specified by:
      convert in interface PropagatorConverter
      Parameters:
      states - spacecraft states sample to fit
      positionOnly - if true, consider only position data otherwise both position and velocity are used
      freeParameters - names of the free parameters
      Returns:
      adapted propagator
      Throws:
      IllegalArgumentException - if one of the parameters cannot be free

    • convert

      public Propagator convert(List<SpacecraftState> states, boolean positionOnly, String... freeParameters) throws IllegalArgumentException
      Find the propagator that minimize the mean square error for a sample of states.
      Specified by:
      convert in interface PropagatorConverter
      Parameters:
      states - spacecraft states sample to fit
      positionOnly - if true, consider only position data otherwise both position and velocity are used
      freeParameters - names of the free parameters
      Returns:
      adapted propagator
      Throws:
      IllegalArgumentException - if one of the parameters cannot be free

    • getAdaptedPropagator

      public Propagator getAdaptedPropagator()
      Get the adapted propagator.
      Returns:
      adapted propagator

    • getRMS

      public double getRMS()
      Get the Root Mean Square Deviation of the fitting.
      Returns:
      RMSD

    • getEvaluations

      public int getEvaluations()
      Get the number of objective function evaluations.
      Returns:
      the number of objective function evaluations.

    • getObjectiveFunction

      protected abstract MultivariateVectorFunction getObjectiveFunction()
      Get the function computing position/velocity at sample points.
      Returns:
      function computing position/velocity at sample points

    • getModel

      protected abstract MultivariateJacobianFunction getModel()
      Get the Jacobian of the function computing position/velocity at sample points.
      Returns:
      Jacobian of the function computing position/velocity at sample points

    • isOnlyPosition

      protected boolean isOnlyPosition()
      Check if fitting uses only sample positions.
      Returns:
      true if fitting uses only sample positions

    • getTargetSize

      protected int getTargetSize()
      Get the size of the target.
      Returns:
      target size

    • getFrame

      protected Frame getFrame()
      Get the frame of the initial state.
      Returns:
      the orbit frame

    • getSample

      protected List<SpacecraftState> getSample()
      Get the states sample.
      Returns:
      the states sample