Package org.orekit.propagation.analytical

Class AbstractAnalyticalPropagator

    • Constructor Detail

      • AbstractAnalyticalPropagator

        protected AbstractAnalyticalPropagator​(AttitudeProvider attitudeProvider)
        Build a new instance.
        Parameters:
        attitudeProvider - provider for attitude computation

    • Method Detail

      • getEphemerisGenerator

        public EphemerisGenerator 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: 

           EphemerisGenerator generator = propagator.getEphemerisGenerator();
   propagator.propagate(target);
   BoundedPropagator ephemeris = generator.getGeneratedEphemeris();
        Returns:
        ephemeris generator

      • propagate

        public SpacecraftState propagate​(AbsoluteDate start,
                                 AbsoluteDate 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.

        Parameters:
        start - start date from which orbit state should be propagated
        target - target date to which orbit state should be propagated
        Returns:
        propagated state

      • getMass

        protected abstract double getMass​(AbsoluteDate date)
        Get the mass.
        Parameters:
        date - target date for the orbit
        Returns:
        mass mass

      • getPvProvider

        public PVCoordinatesProvider getPvProvider()
        Get PV coordinates provider.
        Returns:
        PV coordinates provider

      • resetIntermediateState

        protected abstract void resetIntermediateState​(SpacecraftState 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

        protected abstract Orbit propagateOrbit​(AbsoluteDate date)
        Extrapolate an orbit up to a specific target date.
        Parameters:
        date - target date for the orbit
        Returns:
        extrapolated parameters

      • basicPropagate

        protected SpacecraftState basicPropagate​(AbsoluteDate date)
        Propagate an orbit without any fancy features.

        This method is similar in spirit to the propagate(org.orekit.time.AbsoluteDate, org.orekit.time.AbsoluteDate) 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