1 /* Copyright 2002-2024 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.utils;
18
19 import java.io.Serializable;
20
21 import org.hipparchus.analysis.differentiation.Derivative;
22 import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
23 import org.hipparchus.geometry.euclidean.threed.Vector3D;
24 import org.hipparchus.util.FastMath;
25 import org.orekit.annotation.DefaultDataContext;
26 import org.orekit.data.DataContext;
27 import org.orekit.frames.Frame;
28 import org.orekit.frames.StaticTransform;
29 import org.orekit.frames.Transform;
30 import org.orekit.time.AbsoluteDate;
31 import org.orekit.time.TimeOffset;
32 import org.orekit.time.TimeScale;
33 import org.orekit.time.TimeStamped;
34
35 /** {@link TimeStamped time-stamped} version of {@link PVCoordinates}.
36 * <p>Instances of this class are guaranteed to be immutable.</p>
37 * @author Luc Maisonobe
38 * @since 7.0
39 */
40 public class TimeStampedPVCoordinates extends PVCoordinates implements TimeStamped {
41
42 /** Serializable UID. */
43 private static final long serialVersionUID = 20140723L;
44
45 /** The date. */
46 private final AbsoluteDate date;
47
48 /** Builds a TimeStampedPVCoordinates pair.
49 * @param date coordinates date
50 * @param position the position vector (m)
51 * @param velocity the velocity vector (m/s)
52 * @param acceleration the acceleration vector (m/s²)
53 */
54 public TimeStampedPVCoordinates(final AbsoluteDate date,
55 final Vector3D position, final Vector3D velocity, final Vector3D acceleration) {
56 super(position, velocity, acceleration);
57 this.date = date;
58 }
59
60 /**
61 * Build from position and velocity. Acceleration is set to zero.
62 *
63 * @param date coordinates date
64 * @param position the position vector (m)
65 * @param velocity the velocity vector (m/s)
66 */
67 public TimeStampedPVCoordinates(final AbsoluteDate date,
68 final Vector3D position,
69 final Vector3D velocity) {
70 this(date, position, velocity, Vector3D.ZERO);
71 }
72
73 /**
74 * Build from position velocity acceleration coordinates.
75 *
76 * @param date coordinates date
77 * @param pv position velocity, and acceleration coordinates, in meters and seconds.
78 */
79 public TimeStampedPVCoordinates(final AbsoluteDate date, final PVCoordinates pv) {
80 this(date, pv.getPosition(), pv.getVelocity(), pv.getAcceleration());
81 }
82
83 /** Multiplicative constructor
84 * <p>Build a TimeStampedPVCoordinates from another one and a scale factor.</p>
85 * <p>The TimeStampedPVCoordinates built will be a * pv</p>
86 * @param date date of the built coordinates
87 * @param a scale factor
88 * @param pv base (unscaled) PVCoordinates
89 */
90 public TimeStampedPVCoordinates(final AbsoluteDate date,
91 final double a, final PVCoordinates pv) {
92 super(new Vector3D(a, pv.getPosition()),
93 new Vector3D(a, pv.getVelocity()),
94 new Vector3D(a, pv.getAcceleration()));
95 this.date = date;
96 }
97
98 /** Subtractive constructor
99 * <p>Build a relative TimeStampedPVCoordinates from a start and an end position.</p>
100 * <p>The TimeStampedPVCoordinates built will be end - start.</p>
101 * @param date date of the built coordinates
102 * @param start Starting PVCoordinates
103 * @param end ending PVCoordinates
104 */
105 public TimeStampedPVCoordinates(final AbsoluteDate date,
106 final PVCoordinates start, final PVCoordinates end) {
107 super(end.getPosition().subtract(start.getPosition()),
108 end.getVelocity().subtract(start.getVelocity()),
109 end.getAcceleration().subtract(start.getAcceleration()));
110 this.date = date;
111 }
112
113 /** Linear constructor
114 * <p>Build a TimeStampedPVCoordinates from two other ones and corresponding scale factors.</p>
115 * <p>The TimeStampedPVCoordinates built will be a1 * u1 + a2 * u2</p>
116 * @param date date of the built coordinates
117 * @param a1 first scale factor
118 * @param pv1 first base (unscaled) PVCoordinates
119 * @param a2 second scale factor
120 * @param pv2 second base (unscaled) PVCoordinates
121 */
122 public TimeStampedPVCoordinates(final AbsoluteDate date,
123 final double a1, final PVCoordinates pv1,
124 final double a2, final PVCoordinates pv2) {
125 super(new Vector3D(a1, pv1.getPosition(), a2, pv2.getPosition()),
126 new Vector3D(a1, pv1.getVelocity(), a2, pv2.getVelocity()),
127 new Vector3D(a1, pv1.getAcceleration(), a2, pv2.getAcceleration()));
128 this.date = date;
129 }
130
131 /** Linear constructor
132 * <p>Build a TimeStampedPVCoordinates from three other ones and corresponding scale factors.</p>
133 * <p>The TimeStampedPVCoordinates built will be a1 * u1 + a2 * u2 + a3 * u3</p>
134 * @param date date of the built coordinates
135 * @param a1 first scale factor
136 * @param pv1 first base (unscaled) PVCoordinates
137 * @param a2 second scale factor
138 * @param pv2 second base (unscaled) PVCoordinates
139 * @param a3 third scale factor
140 * @param pv3 third base (unscaled) PVCoordinates
141 */
142 public TimeStampedPVCoordinates(final AbsoluteDate date,
143 final double a1, final PVCoordinates pv1,
144 final double a2, final PVCoordinates pv2,
145 final double a3, final PVCoordinates pv3) {
146 super(new Vector3D(a1, pv1.getPosition(), a2, pv2.getPosition(), a3, pv3.getPosition()),
147 new Vector3D(a1, pv1.getVelocity(), a2, pv2.getVelocity(), a3, pv3.getVelocity()),
148 new Vector3D(a1, pv1.getAcceleration(), a2, pv2.getAcceleration(), a3, pv3.getAcceleration()));
149 this.date = date;
150 }
151
152 /** Linear constructor
153 * <p>Build a TimeStampedPVCoordinates from four other ones and corresponding scale factors.</p>
154 * <p>The TimeStampedPVCoordinates built will be a1 * u1 + a2 * u2 + a3 * u3 + a4 * u4</p>
155 * @param date date of the built coordinates
156 * @param a1 first scale factor
157 * @param pv1 first base (unscaled) PVCoordinates
158 * @param a2 second scale factor
159 * @param pv2 second base (unscaled) PVCoordinates
160 * @param a3 third scale factor
161 * @param pv3 third base (unscaled) PVCoordinates
162 * @param a4 fourth scale factor
163 * @param pv4 fourth base (unscaled) PVCoordinates
164 */
165 public TimeStampedPVCoordinates(final AbsoluteDate date,
166 final double a1, final PVCoordinates pv1,
167 final double a2, final PVCoordinates pv2,
168 final double a3, final PVCoordinates pv3,
169 final double a4, final PVCoordinates pv4) {
170 super(new Vector3D(a1, pv1.getPosition(), a2, pv2.getPosition(), a3, pv3.getPosition(), a4, pv4.getPosition()),
171 new Vector3D(a1, pv1.getVelocity(), a2, pv2.getVelocity(), a3, pv3.getVelocity(), a4, pv4.getVelocity()),
172 new Vector3D(a1, pv1.getAcceleration(), a2, pv2.getAcceleration(), a3, pv3.getAcceleration(), a4, pv4.getAcceleration()));
173 this.date = date;
174 }
175
176 /** Builds a TimeStampedPVCoordinates triplet from a {@link FieldVector3D}<{@link Derivative}>.
177 * <p>
178 * The vector components must have time as their only derivation parameter and
179 * have consistent derivation orders.
180 * </p>
181 * @param date date of the built coordinates
182 * @param p vector with time-derivatives embedded within the coordinates
183 * @param <U> type of the derivative
184 */
185 public <U extends Derivative<U>> TimeStampedPVCoordinates(final AbsoluteDate date, final FieldVector3D<U> p) {
186 super(p);
187 this.date = date;
188 }
189
190 /** {@inheritDoc} */
191 public AbsoluteDate getDate() {
192 return date;
193 }
194
195 /** Get a time-shifted state.
196 * <p>
197 * The state can be slightly shifted to close dates. This shift is based on
198 * a simple Taylor expansion. It is <em>not</em> intended as a replacement for
199 * proper orbit propagation (it is not even Keplerian!) but should be sufficient
200 * for either small time shifts or coarse accuracy.
201 * </p>
202 * @param dt time shift in seconds
203 * @return a new state, shifted with respect to the instance (which is immutable)
204 */
205 public TimeStampedPVCoordinates shiftedBy(final double dt) {
206 final PVCoordinates spv = super.shiftedBy(dt);
207 return new TimeStampedPVCoordinates(date.shiftedBy(dt),
208 spv.getPosition(), spv.getVelocity(), spv.getAcceleration());
209 }
210
211 /** Get a time-shifted state.
212 * <p>
213 * The state can be slightly shifted to close dates. This shift is based on
214 * a simple Taylor expansion. It is <em>not</em> intended as a replacement for
215 * proper orbit propagation (it is not even Keplerian!) but should be sufficient
216 * for either small time shifts or coarse accuracy.
217 * </p>
218 * @param dt time shift
219 * @return a new state, shifted with respect to the instance (which is immutable)
220 * @since 13.0
221 */
222 public TimeStampedPVCoordinates shiftedBy(final TimeOffset dt) {
223 final PVCoordinates spv = super.shiftedBy(dt);
224 return new TimeStampedPVCoordinates(date.shiftedBy(dt),
225 spv.getPosition(), spv.getVelocity(), spv.getAcceleration());
226 }
227
228 /** Create a local provider using simply Taylor expansion through {@link #shiftedBy(double)}.
229 * <p>
230 * The time evolution is based on a simple Taylor expansion. It is <em>not</em> intended as a
231 * replacement for proper orbit propagation (it is not even Keplerian!) but should be sufficient
232 * for either small time shifts or coarse accuracy.
233 * </p>
234 * @param instanceFrame frame in which the instance is defined
235 * @return provider based on Taylor expansion, for small time shifts around instance date
236 */
237 public PVCoordinatesProvider toTaylorProvider(final Frame instanceFrame) {
238 return new PVCoordinatesProvider() {
239 /** {@inheritDoc} */
240 public Vector3D getPosition(final AbsoluteDate d, final Frame f) {
241 final TimeStampedPVCoordinates shifted = shiftedBy(d.durationFrom(getDate()));
242 final StaticTransform transform = instanceFrame.getStaticTransformTo(f, d);
243 return transform.transformPosition(shifted.getPosition());
244 }
245 /** {@inheritDoc} */
246 public TimeStampedPVCoordinates getPVCoordinates(final AbsoluteDate d, final Frame f) {
247 final TimeStampedPVCoordinates shifted = shiftedBy(d.durationFrom(date));
248 final Transform transform = instanceFrame.getTransformTo(f, d);
249 return transform.transformPVCoordinates(shifted);
250 }
251 };
252 }
253
254 /** Return a string representation of this date, position, velocity, and acceleration.
255 *
256 * <p>This method uses the {@link DataContext#getDefault() default data context}.
257 *
258 * @return string representation of this.
259 */
260 @Override
261 @DefaultDataContext
262 public String toString() {
263 return toString(DataContext.getDefault().getTimeScales().getUTC());
264 }
265
266 /**
267 * Return a string representation of this date, position, velocity, and acceleration.
268 *
269 * @param utc time scale used to print the date.
270 * @return string representation of this.
271 */
272 public String toString(final TimeScale utc) {
273 final String comma = ", ";
274 return new StringBuilder().append('{').
275 append(date.toString(utc)).append(", P(").
276 append(getPosition().getX()).append(comma).
277 append(getPosition().getY()).append(comma).
278 append(getPosition().getZ()).append("), V(").
279 append(getVelocity().getX()).append(comma).
280 append(getVelocity().getY()).append(comma).
281 append(getVelocity().getZ()).append("), A(").
282 append(getAcceleration().getX()).append(comma).
283 append(getAcceleration().getY()).append(comma).
284 append(getAcceleration().getZ()).append(")}").toString();
285 }
286
287 /** Replace the instance with a data transfer object for serialization.
288 * @return data transfer object that will be serialized
289 */
290 @DefaultDataContext
291 private Object writeReplace() {
292 return new DTO(this);
293 }
294
295 /** Internal class used only for serialization. */
296 @DefaultDataContext
297 private static class DTO implements Serializable {
298
299 /** Serializable UID. */
300 private static final long serialVersionUID = 20140723L;
301
302 /** Double values. */
303 private final double[] d;
304
305 /** Simple constructor.
306 * @param pv instance to serialize
307 */
308 private DTO(final TimeStampedPVCoordinates pv) {
309
310 // decompose date
311 final AbsoluteDate j2000Epoch =
312 DataContext.getDefault().getTimeScales().getJ2000Epoch();
313 final double epoch = FastMath.floor(pv.getDate().durationFrom(j2000Epoch));
314 final double offset = pv.getDate().durationFrom(j2000Epoch.shiftedBy(epoch));
315
316 this.d = new double[] {
317 epoch, offset,
318 pv.getPosition().getX(), pv.getPosition().getY(), pv.getPosition().getZ(),
319 pv.getVelocity().getX(), pv.getVelocity().getY(), pv.getVelocity().getZ(),
320 pv.getAcceleration().getX(), pv.getAcceleration().getY(), pv.getAcceleration().getZ()
321 };
322
323 }
324
325 /** Replace the deserialized data transfer object with a {@link TimeStampedPVCoordinates}.
326 * @return replacement {@link TimeStampedPVCoordinates}
327 */
328 private Object readResolve() {
329 final AbsoluteDate j2000Epoch =
330 DataContext.getDefault().getTimeScales().getJ2000Epoch();
331 return new TimeStampedPVCoordinates(j2000Epoch.shiftedBy(d[0]).shiftedBy(d[1]),
332 new Vector3D(d[2], d[3], d[ 4]),
333 new Vector3D(d[5], d[6], d[ 7]),
334 new Vector3D(d[8], d[9], d[10]));
335 }
336
337 }
338
339 }