added test for SpinStabilized

src/test/java/org/orekit/attitudes/SpinStabilizedTest.java

+/* Copyright 2002-2008 CS Communication & Systèmes
+ * Licensed to CS Communication & Systèmes (CS) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * CS licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.orekit.attitudes;
+
+import org.apache.commons.math.geometry.Vector3D;
+import org.orekit.errors.OrekitException;
+import org.orekit.forces.Sun;
+import org.orekit.frames.Frame;
+import org.orekit.time.AbsoluteDate;
+import org.orekit.utils.PVCoordinates;
+
+import junit.framework.Test;
+import junit.framework.TestCase;
+import junit.framework.TestSuite;
+
+public class SpinStabilizedTest extends TestCase {
+
+    public SpinStabilizedTest(String name) {
+        super(name);
+    }
+
+    public void testBBQMode() throws OrekitException {
+        Sun sun = new Sun();
+        AbsoluteDate date = new AbsoluteDate(AbsoluteDate.J2000_EPOCH, 12345.6789);
+        double rate = 2.0 * Math.PI / (12 * 60);
+        AttitudeLaw bbq =
+            new SpinStabilized(new CelestialBodyPointed(Frame.getJ2000(), sun, Vector3D.PLUS_K,
+                                     Vector3D.PLUS_I, Vector3D.PLUS_K),
+                               date, Vector3D.PLUS_K, rate);
+        PVCoordinates pv =
+            new PVCoordinates(new Vector3D(28823536.58654545, 5893400.545304828, 0),
+                              new Vector3D(0, 0, 3680.853673522056));
+        Attitude attitude = bbq.getState(date, pv, Frame.getJ2000());
+        Vector3D xDirection = attitude.getRotation().applyInverseTo(Vector3D.PLUS_I);
+        assertEquals(Math.atan(1.0 / 5000.0),
+                     Vector3D.angle(xDirection, sun.getPosition(date, Frame.getJ2000())),
+                     1.0e-15);
+        assertEquals(rate, attitude.getSpin().getNorm(), 1.0e-6);
+
+    }
+
+    public static Test suite() {
+        return new TestSuite(SpinStabilizedTest.class);
+    }
+
+}
+