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.forces.drag;
18  
19  import java.io.Serializable;
20  
21  import org.apache.commons.math3.geometry.euclidean.threed.Vector3D;
22  import org.orekit.errors.OrekitException;
23  import org.orekit.frames.Frame;
24  import org.orekit.time.AbsoluteDate;
25  
26  
27  /** Interface for atmospheric models.
28   * @author Luc Maisonobe
29   */
30  public interface Atmosphere extends Serializable {
31  
32      /** Get the frame of the central body.
33       * @return frame of the central body.
34       * @since 6.0
35       */
36      Frame getFrame();
37  
38      /** Get the local density.
39       * @param date current date
40       * @param position current position in frame
41       * @param frame the frame in which is defined the position
42       * @return local density (kg/m<sup>3</sup>)
43       * @exception OrekitException if date is out of range of solar activity model
44       * or if some frame conversion cannot be performed
45       */
46      double getDensity(AbsoluteDate date, Vector3D position, Frame frame)
47          throws OrekitException;
48  
49      /** Get the inertial velocity of atmosphere molecules.
50       * @param date current date
51       * @param position current position in frame
52       * @param frame the frame in which is defined the position
53       * @return velocity (m/s) (defined in the same frame as the position)
54       * @exception OrekitException if some conversion cannot be performed
55       */
56      Vector3D getVelocity(AbsoluteDate date, Vector3D position, Frame frame)
57          throws OrekitException;
58  
59  }