1   /* Copyright 2002-2022 CS GROUP
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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
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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,
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14   * See the License for the specific language governing permissions and
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16   */
17  package org.orekit.propagation.semianalytical.dsst;
18  
19  import java.io.IOException;
20  import java.text.ParseException;
21  import java.util.Arrays;
22  
23  import org.hipparchus.util.FastMath;
24  import org.junit.Assert;
25  import org.junit.Before;
26  import org.junit.Test;
27  import org.orekit.Utils;
28  import org.orekit.frames.Frame;
29  import org.orekit.frames.FramesFactory;
30  import org.orekit.orbits.EquinoctialOrbit;
31  import org.orekit.orbits.PositionAngle;
32  import org.orekit.propagation.SpacecraftState;
33  import org.orekit.propagation.semianalytical.dsst.forces.DSSTForceModel;
34  import org.orekit.propagation.semianalytical.dsst.forces.DSSTNewtonianAttraction;
35  import org.orekit.propagation.semianalytical.dsst.utilities.AuxiliaryElements;
36  import org.orekit.time.AbsoluteDate;
37  import org.orekit.time.TimeScalesFactory;
38  
39  public class DSSTNewtonianAttractionTest {
40  
41      private static final double eps  = 1.0e-19;
42  
43      @Test
44      public void testGetMeanElementRate() throws IllegalArgumentException {
45          
46          final Frame earthFrame = FramesFactory.getEME2000();
47          
48          final AbsoluteDate date = new AbsoluteDate(2007, 04, 16, 0, 46, 42.400, TimeScalesFactory.getUTC());
49          
50          final double mu = 3.986004415E14;
51          final EquinoctialOrbit orbit = new EquinoctialOrbit(2.655989E7,
52                                                              2.719455286199036E-4,
53                                                              0.0041543085910249414,
54                                                              -0.3412974060023717,
55                                                              0.3960084733107685,
56                                                              FastMath.toRadians(44.2377),
57                                                              PositionAngle.MEAN,
58                                                              earthFrame,
59                                                              date,
60                                                              mu);
61          
62          final SpacecraftState state = new SpacecraftState(orbit);
63          
64          final AuxiliaryElements auxiliaryElements = new AuxiliaryElements(state.getOrbit(), 1);
65          
66          final DSSTForceModel newton = new DSSTNewtonianAttraction(mu);
67  
68          final double[] elements = new double[7];
69          Arrays.fill(elements, 0.0);
70          
71          final double[] daidt = newton.getMeanElementRate(state, auxiliaryElements, newton.getParameters());
72          for (int i = 0; i < daidt.length; i++) {
73              elements[i] = daidt[i];
74          }
75          
76          Assert.assertEquals(0.0,                   elements[0], eps);
77          Assert.assertEquals(0.0,                   elements[1], eps);
78          Assert.assertEquals(0.0,                   elements[2], eps);
79          Assert.assertEquals(0.0,                   elements[3], eps);
80          Assert.assertEquals(0.0,                   elements[4], eps);
81          Assert.assertEquals(1.4585773985530907E-4, elements[5], eps);
82  
83      }
84  
85      @Before
86      public void setUp() throws IOException, ParseException {
87          Utils.setDataRoot("regular-data");
88      }
89  
90  }