1 /* Copyright 2002-2025 CS GROUP
2 * Licensed to CS GROUP (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;
18
19 import java.util.Collection;
20 import java.util.List;
21
22 import org.hipparchus.CalculusFieldElement;
23 import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
24 import org.orekit.attitudes.AttitudeProvider;
25 import org.orekit.frames.Frame;
26 import org.orekit.propagation.events.FieldEventDetector;
27 import org.orekit.propagation.sampling.FieldOrekitFixedStepHandler;
28 import org.orekit.propagation.sampling.FieldOrekitStepHandler;
29 import org.orekit.propagation.sampling.FieldStepHandlerMultiplexer;
30 import org.orekit.time.FieldAbsoluteDate;
31 import org.orekit.utils.FieldPVCoordinatesProvider;
32 import org.orekit.utils.TimeStampedFieldPVCoordinates;
33
34 /** This interface provides a way to propagate an orbit at any time.
35 *
36 * <p>This interface is the top-level abstraction for orbit propagation.
37 * It only allows propagation to a predefined date.
38 * It is implemented by analytical models which have no time limit,
39 * by orbit readers based on external data files, by numerical integrators
40 * using rich force models and by continuous models built after numerical
41 * integration has been completed and dense output data as been
42 * gathered.</p>
43 * @param <T> the type of the field elements
44
45 * @author Luc Maisonobe
46 * @author Véronique Pommier-Maurussane
47 *
48 */
49
50 public interface FieldPropagator<T extends CalculusFieldElement<T>> extends FieldPVCoordinatesProvider<T> {
51
52 /** Default mass. */
53 double DEFAULT_MASS = 1000.0;
54
55 /** Get the multiplexer holding all step handlers.
56 * @return multiplexer holding all step handlers
57 * @since 11.0
58 */
59 FieldStepHandlerMultiplexer<T> getMultiplexer();
60
61 /** Remove all step handlers.
62 * <p>This convenience method is equivalent to call {@code getMultiplexer().clear()}</p>
63 * @see #getMultiplexer()
64 * @see FieldStepHandlerMultiplexer#clear()
65 * @since 11.0
66 */
67 default void clearStepHandlers() {
68 getMultiplexer().clear();
69 }
70
71 /** Set a single handler for fixed stepsizes.
72 * <p>This convenience method is equivalent to call {@code getMultiplexer().clear()}
73 * followed by {@code getMultiplexer().add(h, handler)}</p>
74 * @param h fixed stepsize (s)
75 * @param handler handler called at the end of each finalized step
76 * @see #getMultiplexer()
77 * @see FieldStepHandlerMultiplexer#add(CalculusFieldElement, FieldOrekitFixedStepHandler)
78 * @since 11.0
79 */
80 default void setStepHandler(final T h, final FieldOrekitFixedStepHandler<T> handler) {
81 getMultiplexer().clear();
82 getMultiplexer().add(h, handler);
83 }
84
85 /** Set a single handler for variable stepsizes.
86 * <p>This convenience method is equivalent to call {@code getMultiplexer().clear()}
87 * followed by {@code getMultiplexer().add(handler)}</p>
88 * @param handler handler called at the end of each finalized step
89 * @see #getMultiplexer()
90 * @see FieldStepHandlerMultiplexer#add(FieldOrekitStepHandler)
91 * @since 11.0
92 */
93 default void setStepHandler(final FieldOrekitStepHandler<T> handler) {
94 getMultiplexer().clear();
95 getMultiplexer().add(handler);
96 }
97
98 /**
99 * Set up an ephemeris generator that will monitor the propagation for building
100 * an ephemeris from it once completed.
101 *
102 * <p>
103 * This generator can be used when the user needs fast random access to the orbit
104 * state at any time between the initial and target times. A typical example is the
105 * implementation of search and iterative algorithms that may navigate forward and
106 * backward inside the propagation range before finding their result even if the
107 * propagator used is integration-based and only goes from one initial time to one
108 * target time.
109 * </p>
110 * <p>
111 * Beware that when used with integration-based propagators, the generator will
112 * store <strong>all</strong> intermediate results. It is therefore memory intensive
113 * for long integration-based ranges and high precision/short time steps. When
114 * used with analytical propagators, the generator only stores start/stop time
115 * and a reference to the analytical propagator itself to call it back as needed,
116 * so it is less memory intensive.
117 * </p>
118 * <p>
119 * The returned ephemeris generator will be initially empty, it will be filled
120 * with propagation data when a subsequent call to either {@link #propagate(FieldAbsoluteDate)
121 * propagate(target)} or {@link #propagate(FieldAbsoluteDate, FieldAbsoluteDate)
122 * propagate(start, target)} is called. The proper way to use this method is
123 * therefore to do:
124 * </p>
125 * <pre>
126 * FieldEphemerisGenerator<T> generator = propagator.getEphemerisGenerator();
127 * propagator.propagate(target);
128 * FieldBoundedPropagator<T> ephemeris = generator.getGeneratedEphemeris();
129 * </pre>
130 * @return ephemeris generator
131 */
132 FieldEphemerisGenerator<T> getEphemerisGenerator();
133
134 /** Get the propagator initial state.
135 * @return initial state
136 */
137 FieldSpacecraftState<T> getInitialState();
138
139 /** Reset the propagator initial state.
140 * @param state new initial state to consider
141 */
142 void resetInitialState(FieldSpacecraftState<T> state);
143
144 /** Add a set of user-specified data to be computed along with the orbit propagation.
145 * @param additionalDataProvider provider for additional data
146 */
147 void addAdditionalDataProvider(FieldAdditionalDataProvider<?, T> additionalDataProvider);
148
149 /** Get an unmodifiable list of providers for additional data.
150 * @return providers for the additional states
151 */
152 List<FieldAdditionalDataProvider<?, T>> getAdditionalDataProviders();
153
154 /** Check if an additional data is managed.
155 * <p>
156 * Managed data are the ones for which the propagators know how to compute
157 * its evolution. They correspond to additional data for which an
158 * {@link FieldAdditionalDataProvider additional data provider} has been registered
159 * by calling the {@link #addAdditionalDataProvider(FieldAdditionalDataProvider)
160 * addAdditionalDataProvider} method. If the propagator is an {@link
161 * org.orekit.propagation.integration.FieldAbstractIntegratedPropagator integrator-based
162 * propagator}, the states for which a set of {@link
163 * org.orekit.propagation.integration.FieldAdditionalDerivativesProvider additional derivatives
164 * provider} has been registered by calling the {@link
165 * org.orekit.propagation.integration.FieldAbstractIntegratedPropagator#addAdditionalDerivativesProvider(
166 * org.orekit.propagation.integration.FieldAdditionalDerivativesProvider) addAdditionalDerivativesProvider}
167 * method are also counted as managed additional states.
168 * </p>
169 * <p>
170 * Additional data that are present in the {@link #getInitialState() initial state}
171 * but have no evolution method registered are <em>not</em> considered as managed data.
172 * These unmanaged additional data are not lost during propagation, though. Their
173 * value are piecewise constant between state resets that may change them if some
174 * event handler {@link
175 * org.orekit.propagation.events.handlers.FieldEventHandler#resetState(FieldEventDetector,
176 * FieldSpacecraftState) resetState} method is called at an event occurrence and happens
177 * to change the unmanaged additional data.
178 * </p>
179 * @param name name of the additional data
180 * @return true if the additional data is managed
181 */
182 boolean isAdditionalDataManaged(String name);
183
184 /** Get all the names of all managed data.
185 * @return names of all managed data
186 */
187 String[] getManagedAdditionalData();
188
189 /** Add an event detector.
190 * @param detector event detector to add
191 * @see #clearEventsDetectors()
192 * @see #getEventDetectors()
193 * @param <D> class type for the generic version
194 */
195 <D extends FieldEventDetector<T>> void addEventDetector(D detector);
196
197 /** Get all the events detectors that have been added.
198 * @return an unmodifiable collection of the added detectors
199 * @see #addEventDetector(FieldEventDetector)
200 * @see #clearEventsDetectors()
201 */
202 Collection<FieldEventDetector<T>> getEventDetectors();
203
204 /** Remove all events detectors.
205 * @see #addEventDetector(FieldEventDetector)
206 * @see #getEventDetectors()
207 */
208 void clearEventsDetectors();
209
210 /** Get attitude provider.
211 * @return attitude provider
212 */
213 AttitudeProvider getAttitudeProvider();
214
215 /** Set attitude provider.
216 * @param attitudeProvider attitude provider
217 */
218 void setAttitudeProvider(AttitudeProvider attitudeProvider);
219
220 /** Get the frame in which the orbit is propagated.
221 * <p>
222 * The propagation frame is the definition frame of the initial
223 * state, so this method should be called after this state has
224 * been set, otherwise it may return null.
225 * </p>
226 * @return frame in which the orbit is propagated
227 * @see #resetInitialState(FieldSpacecraftState)
228 */
229 Frame getFrame();
230
231 /** Propagate towards a target date.
232 * <p>Simple propagators use only the target date as the specification for
233 * computing the propagated state. More feature rich propagators can consider
234 * other information and provide different operating modes or G-stop
235 * facilities to stop at pinpointed events occurrences. In these cases, the
236 * target date is only a hint, not a mandatory objective.</p>
237 * @param target target date towards which orbit state should be propagated
238 * @return propagated state
239 */
240 FieldSpacecraftState<T> propagate(FieldAbsoluteDate<T> target);
241
242 /** Propagate from a start date towards a target date.
243 * <p>Those propagators use a start date and a target date to
244 * compute the propagated state. For propagators using event detection mechanism,
245 * if the provided start date is different from the initial state date, a first,
246 * simple propagation is performed, without processing any event computation.
247 * Then complete propagation is performed from start date to target date.</p>
248 * @param start start date from which orbit state should be propagated
249 * @param target target date to which orbit state should be propagated
250 * @return propagated state
251 */
252 FieldSpacecraftState<T> propagate(FieldAbsoluteDate<T> start, FieldAbsoluteDate<T> target);
253
254 /** {@inheritDoc} */
255 @Override
256 default TimeStampedFieldPVCoordinates<T> getPVCoordinates(FieldAbsoluteDate<T> date, Frame frame) {
257 return propagate(date).getPVCoordinates(frame);
258 }
259
260 /** {@inheritDoc} */
261 @Override
262 default FieldVector3D<T> getPosition(final FieldAbsoluteDate<T> date, final Frame frame) {
263 return propagate(date).getPosition(frame);
264 }
265
266 }