EclipseDetector.java

  1. /* Copyright 2002-2013 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.events;

  19. import org.apache.commons.math3.geometry.euclidean.threed.Vector3D;
  20. import org.apache.commons.math3.util.FastMath;
  21. import org.orekit.errors.OrekitException;
  22. import org.orekit.propagation.SpacecraftState;
  23. import org.orekit.propagation.events.handlers.EventHandler;
  24. import org.orekit.propagation.events.handlers.StopOnIncreasing;
  25. import org.orekit.utils.PVCoordinatesProvider;

  27. /** Finder for satellite eclipse related events.
  28.  * <p>This class finds eclipse events, i.e. satellite within umbra (total
  29.  * eclipse) or penumbra (partial eclipse).</p>
  30.  * <p>The default implementation behavior is to {@link
  31.  * org.orekit.propagation.events.handlers.EventHandler.Action#CONTINUE continue}
  32.  * propagation when entering the eclipse and to {@link
  33.  * org.orekit.propagation.events.handlers.EventHandler.Action#STOP stop} propagation
  34.  * when exiting the eclipse. This can be changed by calling {@link
  35.  * #withHandler(EventHandler)} after construction.</p>
  36.  * @see org.orekit.propagation.Propagator#addEventDetector(EventDetector)
  37.  * @author Pascal Parraud
  38.  */
  39. public class EclipseDetector extends AbstractReconfigurableDetector<EclipseDetector> {

  41.     /** Serializable UID. */
  42.     private static final long serialVersionUID = 20131118L;

  44.     /** Occulting body. */
  45.     private final PVCoordinatesProvider occulting;

  47.     /** Occulting body radius (m). */
  48.     private final double occultingRadius;

  50.     /** Occulted body. */
  51.     private final PVCoordinatesProvider occulted;

  53.     /** Occulted body radius (m). */
  54.     private final double occultedRadius;

  56.     /** Umbra, if true, or penumbra, if false, detection flag. */
  57.     private boolean totalEclipse;

  59.     /** Build a new eclipse detector.
  60.      * <p>The new instance is either an umbra detector or a penumbra detector
  61.      * with default values for maximal checking interval ({@link #DEFAULT_MAXCHECK})
  62.      * and convergence threshold ({@link #DEFAULT_THRESHOLD}).</p>
  63.      * @param occulted the body to be occulted
  64.      * @param occultedRadius the radius of the body to be occulted (m)
  65.      * @param occulting the occulting body
  66.      * @param occultingRadius the occulting body radius (m)
  67.      * @param totalEclipse umbra (true) or penumbra (false) detection flag
  68.      * @deprecated as of 6.1 replaced by {@link #EclipseDetector(PVCoordinatesProvider,
  69.      * double, PVCoordinatesProvider, double)} followed by either a call to
  70.      * {@link #withUmbra()} or by a call to {@link #withPenumbra()}
  71.      */
  72.     @Deprecated
  73.     public EclipseDetector(final PVCoordinatesProvider occulted,  final double occultedRadius,
  74.                            final PVCoordinatesProvider occulting, final double occultingRadius,
  75.                            final boolean totalEclipse) {
  76.         this(DEFAULT_MAXCHECK, DEFAULT_THRESHOLD,
  77.              occulted, occultedRadius, occulting, occultingRadius, totalEclipse);
  78.     }

  80.     /** Build a new eclipse detector.
  81.      * <p>The new instance is either an umbra detector or a penumbra detector
  82.      * with default value for convergence threshold ({@link #DEFAULT_THRESHOLD}).</p>
  83.      * <p>The maximal interval between eclipse checks should be smaller than
  84.      * the half duration of the minimal pass to handle, otherwise some short
  85.      * passes could be missed.</p>
  86.      * @param maxCheck maximal checking interval (s)
  87.      * @param occulted the body to be occulted
  88.      * @param occultedRadius the radius of the body to be occulted (m)
  89.      * @param occulting the occulting body
  90.      * @param occultingRadius the occulting body radius (m)
  91.      * @param totalEclipse umbra (true) or penumbra (false) detection flag
  92.      * @deprecated as of 6.1 replaced by {@link #EclipseDetector(double,
  93.      * PVCoordinatesProvider, double, PVCoordinatesProvider, double)} followed by
  94.      * either a call to {@link #withUmbra()} or by a call to {@link #withPenumbra()}
  95.      */
  96.     @Deprecated
  97.     public EclipseDetector(final double maxCheck,
  98.                            final PVCoordinatesProvider occulted,  final double occultedRadius,
  99.                            final PVCoordinatesProvider occulting, final double occultingRadius,
  100.                            final boolean totalEclipse) {
  101.         this(maxCheck, DEFAULT_THRESHOLD,
  102.              occulted, occultedRadius, occulting, occultingRadius, totalEclipse);
  103.     }

  105.     /** Build a new eclipse detector .
  106.      * <p>The new instance is either an umbra detector or a penumbra detector.</p>
  107.      * <p>The maximal interval between eclipse checks should be smaller than
  108.      * the half duration of the minimal pass to handle, otherwise some short
  109.      * passes could be missed.</p>
  110.      * @param maxCheck maximal checking interval (s)
  111.      * @param threshold convergence threshold (s)
  112.      * @param occulted the body to be occulted
  113.      * @param occultedRadius the radius of the body to be occulted (m)
  114.      * @param occulting the occulting body
  115.      * @param occultingRadius the occulting body radius (m)
  116.      * @param totalEclipse umbra (true) or penumbra (false) detection flag
  117.      * @deprecated as of 6.1 replaced by {@link #EclipseDetector(double, double,
  118.      * PVCoordinatesProvider, double, PVCoordinatesProvider, double)} followed by
  119.      * either a call to {@link #withUmbra()} or by a call to {@link #withPenumbra()}
  120.      */
  121.     @Deprecated
  122.     public EclipseDetector(final double maxCheck, final double threshold,
  123.                            final PVCoordinatesProvider occulted, final double occultedRadius,
  124.                            final PVCoordinatesProvider occulting, final double occultingRadius,
  125.                            final boolean totalEclipse) {
  126.         this(maxCheck, threshold, DEFAULT_MAX_ITER, new StopOnIncreasing<EclipseDetector>(),
  127.              occulted, occultedRadius, occulting, occultingRadius, totalEclipse);
  128.     }

  130.     /** Build a new eclipse detector.
  131.      * <p>The new instance is a total eclipse (umbra) detector with default
  132.      * values for maximal checking interval ({@link #DEFAULT_MAXCHECK})
  133.      * and convergence threshold ({@link #DEFAULT_THRESHOLD}).</p>
  134.      * @param occulted the body to be occulted
  135.      * @param occultedRadius the radius of the body to be occulted (m)
  136.      * @param occulting the occulting body
  137.      * @param occultingRadius the occulting body radius (m)
  138.      */
  139.     public EclipseDetector(final PVCoordinatesProvider occulted,  final double occultedRadius,
  140.                            final PVCoordinatesProvider occulting, final double occultingRadius) {
  141.         this(DEFAULT_MAXCHECK, DEFAULT_THRESHOLD,
  142.              occulted, occultedRadius, occulting, occultingRadius);
  143.     }

  145.     /** Build a new eclipse detector.
  146.      * <p>The new instance is a total eclipse (umbra) detector with default
  147.      * value for convergence threshold ({@link #DEFAULT_THRESHOLD}).</p>
  148.      * <p>The maximal interval between eclipse checks should be smaller than
  149.      * the half duration of the minimal pass to handle, otherwise some short
  150.      * passes could be missed.</p>
  151.      * @param maxCheck maximal checking interval (s)
  152.      * @param occulted the body to be occulted
  153.      * @param occultedRadius the radius of the body to be occulted in meters
  154.      * @param occulting the occulting body
  155.      * @param occultingRadius the occulting body radius in meters
  156.      */
  157.     public EclipseDetector(final double maxCheck,
  158.                            final PVCoordinatesProvider occulted,  final double occultedRadius,
  159.                            final PVCoordinatesProvider occulting, final double occultingRadius) {
  160.         this(maxCheck, DEFAULT_THRESHOLD,
  161.              occulted, occultedRadius, occulting, occultingRadius);
  162.     }

  164.     /** Build a new eclipse detector.
  165.      * <p>The new instance is a total eclipse (umbra) detector.</p>
  166.      * <p>The maximal interval between eclipse checks should be smaller than
  167.      * the half duration of the minimal pass to handle, otherwise some short
  168.      * passes could be missed.</p>
  169.      * @param maxCheck maximal checking interval (s)
  170.      * @param threshold convergence threshold (s)
  171.      * @param occulted the body to be occulted
  172.      * @param occultedRadius the radius of the body to be occulted in meters
  173.      * @param occulting the occulting body
  174.      * @param occultingRadius the occulting body radius in meters
  175.      */
  176.     public EclipseDetector(final double maxCheck, final double threshold,
  177.                            final PVCoordinatesProvider occulted,  final double occultedRadius,
  178.                            final PVCoordinatesProvider occulting, final double occultingRadius) {
  179.         this(maxCheck, threshold, DEFAULT_MAX_ITER, new StopOnIncreasing<EclipseDetector>(),
  180.              occulted, occultedRadius, occulting, occultingRadius, true);
  181.     }

  183.     /** Private constructor with full parameters.
  184.      * <p>
  185.      * This constructor is private as users are expected to use the builder
  186.      * API with the various {@code withXxx()} methods to set up the instance
  187.      * in a readable manner without using a huge amount of parameters.
  188.      * </p>
  189.      * @param maxCheck maximum checking interval (s)
  190.      * @param threshold convergence threshold (s)
  191.      * @param maxIter maximum number of iterations in the event time search
  192.      * @param handler event handler to call at event occurrences
  193.      * @param occulted the body to be occulted
  194.      * @param occultedRadius the radius of the body to be occulted in meters
  195.      * @param occulting the occulting body
  196.      * @param occultingRadius the occulting body radius in meters
  197.      * @param totalEclipse umbra (true) or penumbra (false) detection flag
  198.      * @since 6.1
  199.      */
  200.     private EclipseDetector(final double maxCheck, final double threshold,
  201.                             final int maxIter, final EventHandler<EclipseDetector> handler,
  202.                             final PVCoordinatesProvider occulted,  final double occultedRadius,
  203.                             final PVCoordinatesProvider occulting, final double occultingRadius,
  204.                             final boolean totalEclipse) {
  205.         super(maxCheck, threshold, maxIter, handler);
  206.         this.occulted        = occulted;
  207.         this.occultedRadius  = FastMath.abs(occultedRadius);
  208.         this.occulting       = occulting;
  209.         this.occultingRadius = FastMath.abs(occultingRadius);
  210.         this.totalEclipse    = totalEclipse;
  211.     }

  213.     /** {@inheritDoc} */
  214.     @Override
  215.     protected EclipseDetector create(final double newMaxCheck, final double newThreshold,
  216.                                      final int nawMaxIter, final EventHandler<EclipseDetector> newHandler) {
  217.         return new EclipseDetector(newMaxCheck, newThreshold, nawMaxIter, newHandler,
  218.                                    occulted, occultedRadius, occulting, occultingRadius, totalEclipse);
  219.     }

  221.     /**
  222.      * Setup the detector to full umbra detection.
  223.      * <p>
  224.      * This will override a penumbra/umbra flag if it has been configured previously.
  225.      * </p>
  226.      * @return a new detector with updated configuration (the instance is not changed)
  227.      * @see #withPenumbra()
  228.      * @since 6.1
  229.      */
  230.     public EclipseDetector withUmbra() {
  231.         return new EclipseDetector(getMaxCheckInterval(), getThreshold(), getMaxIterationCount(), getHandler(),
  232.                                    occulted, occultedRadius, occulting, occultingRadius,
  233.                                    true);
  234.     }

  236.     /**
  237.      * Setup the detector to penumbra detection.
  238.      * <p>
  239.      * This will override a penumbra/umbra flag if it has been configured previously.
  240.      * </p>
  241.      * @return a new detector with updated configuration (the instance is not changed)
  242.      * @see #withUmbra()
  243.      * @since 6.1
  244.      */
  245.     public EclipseDetector withPenumbra() {
  246.         return new EclipseDetector(getMaxCheckInterval(), getThreshold(), getMaxIterationCount(), getHandler(),
  247.                                    occulted, occultedRadius, occulting, occultingRadius,
  248.                                    false);
  249.     }

  251.     /** Get the occulting body.
  252.      * @return the occulting body
  253.      */
  254.     public PVCoordinatesProvider getOcculting() {
  255.         return occulting;
  256.     }

  258.     /** Get the occulting body radius (m).
  259.      * @return the occulting body radius
  260.      */
  261.     public double getOccultingRadius() {
  262.         return occultingRadius;
  263.     }

  265.     /** Get the occulted body.
  266.      * @return the occulted body
  267.      */
  268.     public PVCoordinatesProvider getOcculted() {
  269.         return occulted;
  270.     }

  272.     /** Get the occulted body radius (m).
  273.      * @return the occulted body radius
  274.      */
  275.     public double getOccultedRadius() {
  276.         return occultedRadius;
  277.     }

  279.     /** Get the total eclipse detection flag.
  280.      * @return the total eclipse detection flag (true for umbra events detection,
  281.      * false for penumbra events detection)
  282.      */
  283.     public boolean getTotalEclipse() {
  284.         return totalEclipse;
  285.     }

  287.     /** Compute the value of the switching function.
  288.      * This function becomes negative when entering the region of shadow
  289.      * and positive when exiting.
  290.      * @param s the current state information: date, kinematics, attitude
  291.      * @return value of the switching function
  292.      * @exception OrekitException if some specific error occurs
  293.      */
  294.     public double g(final SpacecraftState s) throws OrekitException {
  295.         final Vector3D pted = occulted.getPVCoordinates(s.getDate(), s.getFrame()).getPosition();
  296.         final Vector3D ping = occulting.getPVCoordinates(s.getDate(), s.getFrame()).getPosition();
  297.         final Vector3D psat = s.getPVCoordinates().getPosition();
  298.         final Vector3D ps   = pted.subtract(psat);
  299.         final Vector3D po   = ping.subtract(psat);
  300.         final double angle  = Vector3D.angle(ps, po);
  301.         final double rs     = FastMath.asin(occultedRadius / ps.getNorm());
  302.         final double ro     = FastMath.asin(occultingRadius / po.getNorm());
  303.         return totalEclipse ? (angle - ro + rs) : (angle - ro - rs);
  304.     }

  306. }
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