Package org.orekit.propagation.analytical

Class FieldAbstractAnalyticalPropagator<T extends CalculusFieldElement<T>>

java.lang.Object
org.orekit.propagation.FieldAbstractPropagator<T>
org.orekit.propagation.analytical.FieldAbstractAnalyticalPropagator<T>
Type Parameters:
T - type of the field elements
All Implemented Interfaces:
FieldPropagator<T>, FieldPVCoordinatesProvider<T>, ParameterDriversProvider
Direct Known Subclasses:
FieldBrouwerLyddanePropagator, FieldEcksteinHechlerPropagator, FieldEphemeris, FieldGnssPropagator, FieldIntegratedEphemeris, FieldIntelsatElevenElementsPropagator, FieldKeplerianPropagator, FieldTLEPropagator
public abstract class FieldAbstractAnalyticalPropagator<T extends CalculusFieldElement<T>> extends FieldAbstractPropagator<T> implements ParameterDriversProvider
Common handling of FieldPropagator methods for analytical propagators.

This abstract class allows to provide easily the full set of FieldPropagator methods, including all propagation modes support and discrete events support for any simple propagation method. Only two methods must be implemented by derived classes: propagateOrbit(FieldAbsoluteDate, CalculusFieldElement[]) and getMass(FieldAbsoluteDate). The first method should perform straightforward propagation starting from some internally stored initial state up to the specified target date.

Author:
Luc Maisonobe

  • Constructor Details

    • FieldAbstractAnalyticalPropagator

      protected FieldAbstractAnalyticalPropagator(Field<T> field, AttitudeProvider attitudeProvider)
      Build a new instance.
      Parameters:
      field - field used as default
      attitudeProvider - provider for attitude computation

  • Method Details

    • getEphemerisGenerator

      public FieldEphemerisGenerator<T> getEphemerisGenerator()
      Set up an ephemeris generator that will monitor the propagation for building an ephemeris from it once completed.

      This generator can be used when the user needs fast random access to the orbit state at any time between the initial and target times. A typical example is the implementation of search and iterative algorithms that may navigate forward and backward inside the propagation range before finding their result even if the propagator used is integration-based and only goes from one initial time to one target time.

      Beware that when used with integration-based propagators, the generator will store all intermediate results. It is therefore memory intensive for long integration-based ranges and high precision/short time steps. When used with analytical propagators, the generator only stores start/stop time and a reference to the analytical propagator itself to call it back as needed, so it is less memory intensive.

      The returned ephemeris generator will be initially empty, it will be filled with propagation data when a subsequent call to either propagate(target) or propagate(start, target) is called. The proper way to use this method is therefore to do: 

         FieldEphemerisGenerator<T> generator = propagator.getEphemerisGenerator();
   propagator.propagate(target);
   FieldBoundedPropagator<T> ephemeris = generator.getGeneratedEphemeris();
      Specified by:
      getEphemerisGenerator in interface FieldPropagator<T extends CalculusFieldElement<T>>
      Returns:
      ephemeris generator

    • addEventDetector

      public <D extends FieldEventDetector<T>> void addEventDetector(D detector)
      Add an event detector.
      Specified by:
      addEventDetector in interface FieldPropagator<T extends CalculusFieldElement<T>>
      Type Parameters:
      D - class type for the generic version
      Parameters:
      detector - event detector to add
      See Also:

    • getEventDetectors

      public Collection<FieldEventDetector<T>> getEventDetectors()
      Get all the events detectors that have been added.
      Specified by:
      getEventDetectors in interface FieldPropagator<T extends CalculusFieldElement<T>>
      Returns:
      an unmodifiable collection of the added detectors
      See Also:

    • clearEventsDetectors

      public void clearEventsDetectors()
      Remove all events detectors.
      Specified by:
      clearEventsDetectors in interface FieldPropagator<T extends CalculusFieldElement<T>>
      See Also:

    • propagate

      public FieldSpacecraftState<T> propagate(FieldAbsoluteDate<T> start, FieldAbsoluteDate<T> target)
      Propagate from a start date towards a target date.

      Those propagators use a start date and a target date to compute the propagated state. For propagators using event detection mechanism, if the provided start date is different from the initial state date, a first, simple propagation is performed, without processing any event computation. Then complete propagation is performed from start date to target date.

      Specified by:
      propagate in interface FieldPropagator<T extends CalculusFieldElement<T>>
      Parameters:
      start - start date from which orbit state should be propagated
      target - target date to which orbit state should be propagated
      Returns:
      propagated state

    • acceptStep

      protected FieldSpacecraftState<T> acceptStep(FieldAbstractAnalyticalPropagator<T>.org.orekit.propagation.analytical.FieldAbstractAnalyticalPropagator.FieldBasicStepInterpolator interpolator, FieldAbsoluteDate<T> target) throws MathRuntimeException
      Accept a step, triggering events and step handlers.
      Parameters:
      interpolator - interpolator for the current step
      target - final propagation time
      Returns:
      state at the end of the step
      Throws:
      MathRuntimeException - if an event cannot be located

    • getMass

      protected abstract T getMass(FieldAbsoluteDate<T> date)
      Get the mass.
      Parameters:
      date - target date for the orbit
      Returns:
      mass mass

    • resetIntermediateState

      protected abstract void resetIntermediateState(FieldSpacecraftState<T> state, boolean forward)
      Reset an intermediate state.
      Parameters:
      state - new intermediate state to consider
      forward - if true, the intermediate state is valid for propagations after itself

    • propagateOrbit

      public abstract FieldOrbit<T> propagateOrbit(FieldAbsoluteDate<T> date, T[] parameters)
      Propagate an orbit up to a specific target date.
      Parameters:
      date - target date for the orbit
      parameters - model parameters
      Returns:
      propagated orbit

    • basicPropagate

      public FieldSpacecraftState<T> basicPropagate(FieldAbsoluteDate<T> date)
      Propagate an orbit without any fancy features.

      This method is similar in spirit to the propagate(org.orekit.time.FieldAbsoluteDate<T>, org.orekit.time.FieldAbsoluteDate<T>) method, except that it does not call any handler during propagation, nor any discrete events, not additional states. It always stop exactly at the specified date.

      Parameters:
      date - target date for propagation
      Returns:
      state at specified date