Java tutorial
/* Copyright 2002-2015 CS Systmes d'Information * Licensed to CS Systmes d'Information (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.frames; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import org.apache.commons.math3.geometry.euclidean.threed.Rotation; import org.apache.commons.math3.geometry.euclidean.threed.Vector3D; import org.apache.commons.math3.util.FastMath; import org.junit.Assert; import org.junit.Before; import org.junit.Test; import org.orekit.Utils; import org.orekit.errors.OrekitException; import org.orekit.time.AbsoluteDate; import org.orekit.time.DateComponents; import org.orekit.time.TimeComponents; import org.orekit.time.TimeScalesFactory; import org.orekit.utils.IERSConventions; import org.orekit.utils.PVCoordinates; public class GTODProviderTest { @Test public void testAASReferenceLEO() throws OrekitException { // this reference test has been extracted from the following paper: // Implementation Issues Surrounding the New IAU Reference Systems for Astrodynamics // David A. Vallado, John H. Seago, P. Kenneth Seidelmann // http://www.centerforspace.com/downloads/files/pubs/AAS-06-134.pdf Utils.setLoaders(IERSConventions.IERS_1996, Utils.buildEOPList(IERSConventions.IERS_1996, new double[][] { { 53098, -0.4399619, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN }, { 53099, -0.4399619, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN }, { 53100, -0.4399619, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN }, { 53101, -0.4399619, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN }, { 53102, -0.4399619, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN }, { 53103, -0.4399619, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN }, { 53104, -0.4399619, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN }, { 53105, -0.4399619, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN } })); AbsoluteDate t0 = new AbsoluteDate(new DateComponents(2004, 04, 06), new TimeComponents(07, 51, 28.386009), TimeScalesFactory.getUTC()); // PEF iau76 PVCoordinates pvPEF = new PVCoordinates(new Vector3D(-1033475.0313, 7901305.5856, 6380344.5328), new Vector3D(-3225.632747, -2872.442511, 5531.931288)); // it seems the induced effect of pole nutation correction on the equation of the equinoxes // was not taken into account in the reference paper, so we fix it here for the test final double dDeltaPsi = FramesFactory.getEOPHistory(IERSConventions.IERS_1996, true) .getEquinoxNutationCorrection(t0)[0]; final double epsilonA = IERSConventions.IERS_1996.getMeanObliquityFunction().value(t0); final Transform fix = new Transform(t0, new Rotation(Vector3D.PLUS_K, -dDeltaPsi * FastMath.cos(epsilonA))); // TOD iau76 PVCoordinates pvTOD = new PVCoordinates(new Vector3D(5094514.7804, 6127366.4612, 6380344.5328), new Vector3D(-4746.088567, 786.077222, 5531.931288)); Transform t = FramesFactory.getTOD(IERSConventions.IERS_1996, true) .getTransformTo(FramesFactory.getGTOD(IERSConventions.IERS_1996, true), t0); checkPV(fix.transformPVCoordinates(pvPEF), t.transformPVCoordinates(pvTOD), 0.00942, 3.12e-5); // if we forget to apply nutation corrections, results are much worse, which is expected t = FramesFactory.getTOD(false).getTransformTo(FramesFactory.getGTOD(false), t0); checkPV(fix.transformPVCoordinates(pvPEF), t.transformPVCoordinates(pvTOD), 257.49, 0.13955); } @Test public void testAASReferenceGEO() throws OrekitException { // this reference test has been extracted from the following paper: // Implementation Issues Surrounding the New IAU Reference Systems for Astrodynamics // David A. Vallado, John H. Seago, P. Kenneth Seidelmann // http://www.centerforspace.com/downloads/files/pubs/AAS-06-134.pdf Utils.setLoaders(IERSConventions.IERS_1996, Utils.buildEOPList(IERSConventions.IERS_1996, new double[][] { { 53153, -0.4709050, 0.0000000, -0.083853, 0.467217, -0.053614, -0.004494, Double.NaN, Double.NaN }, { 53154, -0.4709050, 0.0000000, -0.083853, 0.467217, -0.053614, -0.004494, Double.NaN, Double.NaN }, { 53155, -0.4709050, 0.0000000, -0.083853, 0.467217, -0.053614, -0.004494, Double.NaN, Double.NaN }, { 53156, -0.4709050, 0.0000000, -0.083853, 0.467217, -0.053614, -0.004494, Double.NaN, Double.NaN }, { 53157, -0.4709050, 0.0000000, -0.083853, 0.467217, -0.053614, -0.004494, Double.NaN, Double.NaN }, { 53158, -0.4709050, 0.0000000, -0.083853, 0.467217, -0.053614, -0.004494, Double.NaN, Double.NaN }, { 53159, -0.4709050, 0.0000000, -0.083853, 0.467217, -0.053614, -0.004494, Double.NaN, Double.NaN }, { 53160, -0.4709050, 0.0000000, -0.083853, 0.467217, -0.053614, -0.004494, Double.NaN, Double.NaN } })); AbsoluteDate t0 = new AbsoluteDate(new DateComponents(2004, 06, 01), TimeComponents.H00, TimeScalesFactory.getUTC()); Transform t = FramesFactory.getTOD(IERSConventions.IERS_1996, true) .getTransformTo(FramesFactory.getGTOD(IERSConventions.IERS_1996, true), t0); // TOD iau76 PVCoordinates pvTOD = new PVCoordinates(new Vector3D(-40577427.7501, -11500096.1306, 10293.2583), new Vector3D(837.552338, -2957.524176, -0.928772)); // PEF iau76 PVCoordinates pvPEF = new PVCoordinates(new Vector3D(24796919.2956, -34115870.9001, 10293.2583), new Vector3D(-0.979178, -1.476540, -0.928772)); // it seems the induced effect of pole nutation correction on the equation of the equinoxes // was not taken into account in the reference paper, so we fix it here for the test final double dDeltaPsi = FramesFactory.getEOPHistory(IERSConventions.IERS_1996, true) .getEquinoxNutationCorrection(t0)[0]; final double epsilonA = IERSConventions.IERS_1996.getMeanObliquityFunction().value(t0); final Transform fix = new Transform(t0, new Rotation(Vector3D.PLUS_K, -dDeltaPsi * FastMath.cos(epsilonA))); checkPV(fix.transformPVCoordinates(pvPEF), t.transformPVCoordinates(pvTOD), 0.0503, 3.59e-4); // if we forget to apply nutation corrections, results are much worse, which is expected t = FramesFactory.getTOD(false).getTransformTo(FramesFactory.getGTOD(false), t0); checkPV(fix.transformPVCoordinates(pvPEF), t.transformPVCoordinates(pvTOD), 1458.27, 3.847e-4); } @Test public void testSerialization() throws OrekitException, IOException, ClassNotFoundException { GTODProvider provider = new GTODProvider(IERSConventions.IERS_2010, FramesFactory.getEOPHistory(IERSConventions.IERS_2010, true)); ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(provider); Assert.assertTrue(bos.size() > 280000); Assert.assertTrue(bos.size() < 285000); ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray()); ObjectInputStream ois = new ObjectInputStream(bis); GTODProvider deserialized = (GTODProvider) ois.readObject(); for (int i = 0; i < FastMath.min(100, provider.getEOPHistory().getEntries().size()); ++i) { AbsoluteDate date = provider.getEOPHistory().getEntries().get(i).getDate(); Transform expectedIdentity = new Transform(date, provider.getTransform(date).getInverse(), deserialized.getTransform(date)); Assert.assertEquals(0.0, expectedIdentity.getTranslation().getNorm(), 1.0e-15); Assert.assertEquals(0.0, expectedIdentity.getRotation().getAngle(), 1.0e-15); } } @Before public void setUp() { Utils.setDataRoot("compressed-data"); } private void checkPV(PVCoordinates reference, PVCoordinates result, double expectedPositionError, double expectedVelocityError) { Vector3D dP = result.getPosition().subtract(reference.getPosition()); Vector3D dV = result.getVelocity().subtract(reference.getVelocity()); Assert.assertEquals(expectedPositionError, dP.getNorm(), 0.01 * expectedPositionError); Assert.assertEquals(expectedVelocityError, dV.getNorm(), 0.01 * expectedVelocityError); } }