FieldEclipseDetector.java
- /* Copyright 2002-2024 CS GROUP
- * Licensed to CS GROUP (CS) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * CS licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package org.orekit.propagation.events;
- import org.hipparchus.CalculusFieldElement;
- import org.hipparchus.Field;
- import org.hipparchus.ode.events.Action;
- import org.orekit.bodies.OneAxisEllipsoid;
- import org.orekit.propagation.FieldSpacecraftState;
- import org.orekit.propagation.events.handlers.FieldEventHandler;
- import org.orekit.propagation.events.handlers.FieldStopOnIncreasing;
- import org.orekit.utils.ExtendedPVCoordinatesProvider;
- import org.orekit.utils.OccultationEngine;
- /** Finder for satellite eclipse related events.
- * <p>This class finds eclipse events, i.e. satellite within umbra (total
- * eclipse) or penumbra (partial eclipse).</p>
- * <p>The default implementation behavior is to {@link Action#CONTINUE continue}
- * propagation when entering the eclipse and to {@link Action#STOP stop} propagation
- * when exiting the eclipse. This can be changed by calling {@link
- * #withHandler(FieldEventHandler)} after construction.</p>
- * @param <T> the type of the field elements
- * @see org.orekit.propagation.FieldPropagator#addEventDetector(FieldEventDetector)
- * @author Pascal Parraud
- */
- public class FieldEclipseDetector<T extends CalculusFieldElement<T>> extends FieldAbstractDetector<FieldEclipseDetector<T>, T> {
- /** Occultation engine.
- * @since 12.0
- */
- private final OccultationEngine occultationEngine;
- /** Umbra, if true, or penumbra, if false, detection flag. */
- private boolean totalEclipse;
- /** Margin to apply to eclipse angle. */
- private final T margin;
- /** Build a new eclipse detector.
- * <p>The new instance is a total eclipse (umbra) detector with default
- * values for maximal checking interval ({@link #DEFAULT_MAXCHECK})
- * and convergence threshold ({@link #DEFAULT_THRESHOLD}).</p>
- * @param field field used by default
- * @param occulted the body to be occulted
- * @param occultedRadius the radius of the body to be occulted (m)
- * @param occulting the occulting body
- * @since 12.0
- */
- public FieldEclipseDetector(final Field<T> field,
- final ExtendedPVCoordinatesProvider occulted, final double occultedRadius,
- final OneAxisEllipsoid occulting) {
- this(field, new OccultationEngine(occulted, occultedRadius, occulting));
- }
- /** Build a new eclipse detector.
- * <p>The new instance is a total eclipse (umbra) detector with default
- * values for maximal checking interval ({@link #DEFAULT_MAXCHECK})
- * and convergence threshold ({@link #DEFAULT_THRESHOLD}).</p>
- * @param field field used by default
- * @param occultationEngine occultation engine
- * @since 12.0
- */
- public FieldEclipseDetector(final Field<T> field, final OccultationEngine occultationEngine) {
- this(FieldAdaptableInterval.of(DEFAULT_MAXCHECK), field.getZero().newInstance(DEFAULT_THRESHOLD),
- DEFAULT_MAX_ITER, new FieldStopOnIncreasing<>(),
- occultationEngine, field.getZero(), true);
- }
- /** Protected constructor with full parameters.
- * <p>
- * This constructor is not public as users are expected to use the builder
- * API with the various {@code withXxx()} methods to set up the instance
- * in a readable manner without using a huge amount of parameters.
- * </p>
- * @param maxCheck maximum checking interval
- * @param threshold convergence threshold (s)
- * @param maxIter maximum number of iterations in the event time search
- * @param handler event handler to call at event occurrences
- * @param occultationEngine occultation engine
- * @param margin to apply to eclipse angle (rad)
- * @param totalEclipse umbra (true) or penumbra (false) detection flag
- * @since 12.0
- */
- protected FieldEclipseDetector(final FieldAdaptableInterval<T> maxCheck, final T threshold,
- final int maxIter, final FieldEventHandler<T> handler,
- final OccultationEngine occultationEngine, final T margin, final boolean totalEclipse) {
- super(maxCheck, threshold, maxIter, handler);
- this.occultationEngine = occultationEngine;
- this.margin = margin;
- this.totalEclipse = totalEclipse;
- }
- /** {@inheritDoc} */
- @Override
- protected FieldEclipseDetector<T> create(final FieldAdaptableInterval<T> newMaxCheck, final T newThreshold, final int nawMaxIter,
- final FieldEventHandler<T> newHandler) {
- return new FieldEclipseDetector<>(newMaxCheck, newThreshold, nawMaxIter, newHandler,
- occultationEngine, margin, totalEclipse);
- }
- /**
- * Setup the detector to full umbra detection.
- * <p>
- * This will override a penumbra/umbra flag if it has been configured previously.
- * </p>
- * @return a new detector with updated configuration (the instance is not changed)
- * @see #withPenumbra()
- * @since 6.1
- */
- public FieldEclipseDetector<T> withUmbra() {
- return new FieldEclipseDetector<>(getMaxCheckInterval(), getThreshold(), getMaxIterationCount(), getHandler(),
- occultationEngine, margin, true);
- }
- /**
- * Setup the detector to penumbra detection.
- * <p>
- * This will override a penumbra/umbra flag if it has been configured previously.
- * </p>
- * @return a new detector with updated configuration (the instance is not changed)
- * @see #withUmbra()
- * @since 6.1
- */
- public FieldEclipseDetector<T> withPenumbra() {
- return new FieldEclipseDetector<>(getMaxCheckInterval(), getThreshold(), getMaxIterationCount(), getHandler(),
- occultationEngine, margin, false);
- }
- /**
- * Setup a margin to angle detection.
- * <p>
- * A positive margin implies eclipses are "larger" hence entry occurs earlier and exit occurs later
- * than a detector with 0 margin.
- * </p>
- * @param newMargin angular margin to apply to eclipse detection (rad)
- * @return a new detector with updated configuration (the instance is not changed)
- * @since 12.0
- */
- public FieldEclipseDetector<T> withMargin(final T newMargin) {
- return new FieldEclipseDetector<>(getMaxCheckInterval(), getThreshold(), getMaxIterationCount(), getHandler(),
- occultationEngine, newMargin, totalEclipse);
- }
- /** Get the angular margin used for eclipse detection.
- * @return angular margin used for eclipse detection (rad)
- * @since 12.0
- */
- public T getMargin() {
- return margin;
- }
- /** Get the occultation engine.
- * @return occultation engine
- * @since 12.0
- */
- public OccultationEngine getOccultationEngine() {
- return occultationEngine;
- }
- /** Get the total eclipse detection flag.
- * @return the total eclipse detection flag (true for umbra events detection,
- * false for penumbra events detection)
- */
- public boolean getTotalEclipse() {
- return totalEclipse;
- }
- /** Compute the value of the switching function.
- * This function becomes negative when entering the region of shadow
- * and positive when exiting.
- * @param s the current state information: date, kinematics, attitude
- * @return value of the switching function
- */
- public T g(final FieldSpacecraftState<T> s) {
- final OccultationEngine.FieldOccultationAngles<T> angles = occultationEngine.angles(s);
- return totalEclipse ?
- angles.getSeparation().subtract(angles.getLimbRadius()).add(angles.getOccultedApparentRadius().add(margin)) :
- angles.getSeparation().subtract(angles.getLimbRadius()).subtract(angles.getOccultedApparentRadius().add(margin));
- }
- }