1   /* Copyright 2002-2021 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  
18  package org.orekit.utils;
19  
20  import org.hipparchus.CalculusFieldElement;
21  import org.orekit.frames.Frame;
22  import org.orekit.time.FieldAbsoluteDate;
23  
24  /**
25  ** Interface for PV coordinates providers.
26   * @param <T> the type of the field elements
27   * @author Veronique Pommier
28   * <p>The PV coordinates provider interface can be used by any class used for position/velocity
29   * computation, for example celestial bodies or spacecraft position/velocity propagators,
30   * and many others...
31   * </p>
32   */
33  public interface FieldPVCoordinatesProvider<T extends CalculusFieldElement<T>> {
34  
35      /** Get the {@link FieldPVCoordinates} of the body in the selected frame.
36       * @param date current date
37       * @param frame the frame where to define the position
38       * @return time-stamped position/velocity of the body (m and m/s)
39       */
40      TimeStampedFieldPVCoordinates<T> getPVCoordinates(FieldAbsoluteDate<T> date, Frame frame);
41  
42  }