Propagator.java

  1. /* Copyright 2002-2018 CS Systèmes d'Information
  2.  * Licensed to CS Systèmes d'Information (CS) under one or more
  3.  * contributor license agreements.  See the NOTICE file distributed with
  4.  * this work for additional information regarding copyright ownership.
  5.  * CS licenses this file to You under the Apache License, Version 2.0
  6.  * (the "License"); you may not use this file except in compliance with
  7.  * the License.  You may obtain a copy of the License at
  8.  *
  9.  *   http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  17. package org.orekit.propagation;

  19. import java.util.Collection;
  20. import java.util.List;

  22. import org.orekit.attitudes.AttitudeProvider;
  23. import org.orekit.attitudes.InertialProvider;
  24. import org.orekit.errors.OrekitException;
  25. import org.orekit.frames.Frame;
  26. import org.orekit.propagation.events.EventDetector;
  27. import org.orekit.propagation.sampling.OrekitFixedStepHandler;
  28. import org.orekit.propagation.sampling.OrekitStepHandler;
  29. import org.orekit.time.AbsoluteDate;
  30. import org.orekit.utils.PVCoordinatesProvider;

  32. /** This interface provides a way to propagate an orbit at any time.
  33.  *
  34.  * <p>This interface is the top-level abstraction for orbit propagation.
  35.  * It only allows propagation to a predefined date.
  36.  * It is implemented by analytical models which have no time limit,
  37.  * by orbit readers based on external data files, by numerical integrators
  38.  * using rich force models and by continuous models built after numerical
  39.  * integration has been completed and dense output data as been
  40.  * gathered.</p>

  42.  * @author Luc Maisonobe
  43.  * @author V&eacute;ronique Pommier-Maurussane
  44.  *
  45.  */

  47. public interface Propagator extends PVCoordinatesProvider {

  49.     /** Default mass. */
  50.     double DEFAULT_MASS = 1000.0;

  52.     /** Default attitude provider. */
  53.     AttitudeProvider DEFAULT_LAW = InertialProvider.EME2000_ALIGNED;

  55.     /** Indicator for slave mode. */
  56.     int SLAVE_MODE = 0;

  58.     /** Indicator for master mode. */
  59.     int MASTER_MODE = 1;

  61.     /** Indicator for ephemeris generation mode. */
  62.     int EPHEMERIS_GENERATION_MODE = 2;

  64.     /** Get the current operating mode of the propagator.
  65.      * @return one of {@link #SLAVE_MODE}, {@link #MASTER_MODE},
  66.      * {@link #EPHEMERIS_GENERATION_MODE}
  67.      * @see #setSlaveMode()
  68.      * @see #setMasterMode(double, OrekitFixedStepHandler)
  69.      * @see #setMasterMode(OrekitStepHandler)
  70.      * @see #setEphemerisMode()
  71.      */
  72.     int getMode();

  74.     /** Set the propagator to slave mode.
  75.      * <p>This mode is used when the user needs only the final orbit at the target time.
  76.      *  The (slave) propagator computes this result and return it to the calling
  77.      *  (master) application, without any intermediate feedback.
  78.      * <p>This is the default mode.</p>
  79.      * @see #setMasterMode(double, OrekitFixedStepHandler)
  80.      * @see #setMasterMode(OrekitStepHandler)
  81.      * @see #setEphemerisMode()
  82.      * @see #getMode()
  83.      * @see #SLAVE_MODE
  84.      */
  85.     void setSlaveMode();

  87.     /** Set the propagator to master mode with fixed steps.
  88.      * <p>This mode is used when the user needs to have some custom function called at the
  89.      * end of each finalized step during integration. The (master) propagator integration
  90.      * loop calls the (slave) application callback methods at each finalized step.</p>
  91.      * @param h fixed stepsize (s)
  92.      * @param handler handler called at the end of each finalized step
  93.      * @see #setSlaveMode()
  94.      * @see #setMasterMode(OrekitStepHandler)
  95.      * @see #setEphemerisMode()
  96.      * @see #getMode()
  97.      * @see #MASTER_MODE
  98.      */
  99.     void setMasterMode(double h, OrekitFixedStepHandler handler);

  101.     /** Set the propagator to master mode with variable steps.
  102.      * <p>This mode is used when the user needs to have some custom function called at the
  103.      * end of each finalized step during integration. The (master) propagator integration
  104.      * loop calls the (slave) application callback methods at each finalized step.</p>
  105.      * @param handler handler called at the end of each finalized step
  106.      * @see #setSlaveMode()
  107.      * @see #setMasterMode(double, OrekitFixedStepHandler)
  108.      * @see #setEphemerisMode()
  109.      * @see #getMode()
  110.      * @see #MASTER_MODE
  111.      */
  112.     void setMasterMode(OrekitStepHandler handler);

  114.     /** Set the propagator to ephemeris generation mode.
  115.      *  <p>This mode is used when the user needs random access to the orbit state at any time
  116.      *  between the initial and target times, and in no sequential order. A typical example is
  117.      *  the implementation of search and iterative algorithms that may navigate forward and
  118.      *  backward inside the propagation range before finding their result.</p>
  119.      *  <p>Beware that since this mode stores <strong>all</strong> intermediate results,
  120.      *  it may be memory intensive for long integration ranges and high precision/short
  121.      *  time steps.</p>
  122.      * @see #getGeneratedEphemeris()
  123.      * @see #setSlaveMode()
  124.      * @see #setMasterMode(double, OrekitFixedStepHandler)
  125.      * @see #setMasterMode(OrekitStepHandler)
  126.      * @see #getMode()
  127.      * @see #EPHEMERIS_GENERATION_MODE
  128.      */
  129.     void setEphemerisMode();

  131.     /**
  132.      * Set the propagator to ephemeris generation mode with the specified handler for each
  133.      * integration step.
  134.      *
  135.      * <p>This mode is used when the user needs random access to the orbit state at any
  136.      * time between the initial and target times, as well as access to the steps computed
  137.      * by the integrator as in Master Mode. A typical example is the implementation of
  138.      * search and iterative algorithms that may navigate forward and backward inside the
  139.      * propagation range before finding their result.</p>
  140.      *
  141.      * <p>Beware that since this mode stores <strong>all</strong> intermediate results, it
  142.      * may be memory intensive for long integration ranges and high precision/short time
  143.      * steps.</p>
  144.      *
  145.      * @param handler handler called at the end of each finalized step
  146.      * @see #setEphemerisMode()
  147.      * @see #getGeneratedEphemeris()
  148.      * @see #setSlaveMode()
  149.      * @see #setMasterMode(double, OrekitFixedStepHandler)
  150.      * @see #setMasterMode(OrekitStepHandler)
  151.      * @see #getMode()
  152.      * @see #EPHEMERIS_GENERATION_MODE
  153.      */
  154.     void setEphemerisMode(OrekitStepHandler handler);

  156.     /** Get the ephemeris generated during propagation.
  157.      * @return generated ephemeris
  158.      * @exception IllegalStateException if the propagator was not set in ephemeris
  159.      * generation mode before propagation
  160.      * @see #setEphemerisMode()
  161.      */
  162.     BoundedPropagator getGeneratedEphemeris() throws IllegalStateException;

  164.     /** Get the propagator initial state.
  165.      * @return initial state
  166.      * @exception OrekitException if state cannot be retrieved
  167.      */
  168.     SpacecraftState getInitialState() throws OrekitException;

  170.     /** Reset the propagator initial state.
  171.      * @param state new initial state to consider
  172.      * @exception OrekitException if initial state cannot be reset
  173.      */
  174.     void resetInitialState(SpacecraftState state)
  175.         throws OrekitException;

  177.     /** Add a set of user-specified state parameters to be computed along with the orbit propagation.
  178.      * @param additionalStateProvider provider for additional state
  179.      * @exception OrekitException if an additional state with the same name is already present
  180.      */
  181.     void addAdditionalStateProvider(AdditionalStateProvider additionalStateProvider)
  182.         throws OrekitException;

  184.     /** Get an unmodifiable list of providers for additional state.
  185.      * @return providers for the additional states
  186.      */
  187.     List<AdditionalStateProvider> getAdditionalStateProviders();

  189.     /** Check if an additional state is managed.
  190.      * <p>
  191.      * Managed states are states for which the propagators know how to compute
  192.      * its evolution. They correspond to additional states for which an
  193.      * {@link AdditionalStateProvider additional state provider} has been registered
  194.      * by calling the {@link #addAdditionalStateProvider(AdditionalStateProvider)
  195.      * addAdditionalStateProvider} method. If the propagator is an {@link
  196.      * org.orekit.propagation.integration.AbstractIntegratedPropagator integrator-based
  197.      * propagator}, the states for which a set of {@link
  198.      * org.orekit.propagation.integration.AdditionalEquations additional equations} has
  199.      * been registered by calling the {@link
  200.      * org.orekit.propagation.integration.AbstractIntegratedPropagator#addAdditionalEquations(
  201.      * org.orekit.propagation.integration.AdditionalEquations) addAdditionalEquations}
  202.      * method are also counted as managed additional states.
  203.      * </p>
  204.      * <p>
  205.      * Additional states that are present in the {@link #getInitialState() initial state}
  206.      * but have no evolution method registered are <em>not</em> considered as managed states.
  207.      * These unmanaged additional states are not lost during propagation, though. Their
  208.      * value will simply be copied unchanged throughout propagation.
  209.      * </p>
  210.      * @param name name of the additional state
  211.      * @return true if the additional state is managed
  212.      */
  213.     boolean isAdditionalStateManaged(String name);

  215.     /** Get all the names of all managed states.
  216.      * @return names of all managed states
  217.      */
  218.     String[] getManagedAdditionalStates();

  220.     /** Add an event detector.
  221.      * @param detector event detector to add
  222.      * @see #clearEventsDetectors()
  223.      * @see #getEventsDetectors()
  224.      * @param <T> class type for the generic version
  225.      */
  226.     <T extends EventDetector> void addEventDetector(T detector);

  228.     /** Get all the events detectors that have been added.
  229.      * @return an unmodifiable collection of the added detectors
  230.      * @see #addEventDetector(EventDetector)
  231.      * @see #clearEventsDetectors()
  232.      */
  233.     Collection<EventDetector> getEventsDetectors();

  235.     /** Remove all events detectors.
  236.      * @see #addEventDetector(EventDetector)
  237.      * @see #getEventsDetectors()
  238.      */
  239.     void clearEventsDetectors();

  241.     /** Get attitude provider.
  242.      * @return attitude provider
  243.      */
  244.     AttitudeProvider getAttitudeProvider();

  246.     /** Set attitude provider.
  247.      * @param attitudeProvider attitude provider
  248.      */
  249.     void setAttitudeProvider(AttitudeProvider attitudeProvider);

  251.     /** Get the frame in which the orbit is propagated.
  252.      * <p>
  253.      * The propagation frame is the definition frame of the initial
  254.      * state, so this method should be called after this state has
  255.      * been set, otherwise it may return null.
  256.      * </p>
  257.      * @return frame in which the orbit is propagated
  258.      * @see #resetInitialState(SpacecraftState)
  259.      */
  260.     Frame getFrame();

  262.     /** Propagate towards a target date.
  263.      * <p>Simple propagators use only the target date as the specification for
  264.      * computing the propagated state. More feature rich propagators can consider
  265.      * other information and provide different operating modes or G-stop
  266.      * facilities to stop at pinpointed events occurrences. In these cases, the
  267.      * target date is only a hint, not a mandatory objective.</p>
  268.      * @param target target date towards which orbit state should be propagated
  269.      * @return propagated state
  270.      * @exception OrekitException if state cannot be propagated
  271.      */
  272.     SpacecraftState propagate(AbsoluteDate target) throws OrekitException;

  274.     /** Propagate from a start date towards a target date.
  275.      * <p>Those propagators use a start date and a target date to
  276.      * compute the propagated state. For propagators using event detection mechanism,
  277.      * if the provided start date is different from the initial state date, a first,
  278.      * simple propagation is performed, without processing any event computation.
  279.      * Then complete propagation is performed from start date to target date.</p>
  280.      * @param start start date from which orbit state should be propagated
  281.      * @param target target date to which orbit state should be propagated
  282.      * @return propagated state
  283.      * @exception OrekitException if state cannot be propagated
  284.      */
  285.     SpacecraftState propagate(AbsoluteDate start, AbsoluteDate target) throws OrekitException;

  287. }
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