Examples with TimeScale org.orekit.time.TimeScale used on opensource projects

Example 41 with TimeScale

use of org.orekit.time.TimeScale in project Orekit by CS-SI.

the class TideTest method doTestSort.

private void doTestSort(int tauMultiplier, Tide... tides) throws OrekitException {
    // this test checks that tides sort order is date-independent for a large time range
    // (almost 180000 years long)
    // tides sort-order is based on rate, but the rates varies slightly with dates
    // (because Delaunay nutation arguments are polynomials)
    // The variations are however small and we want to make sure
    // that if rate(tideA) < rate(tideB) at time t0, this order remains
    // the same for t1 a few millenia around t0
    TimeScale ut1 = TimeScalesFactory.getUT1(IERSConventions.IERS_2010, true);
    FundamentalNutationArguments fna = IERSConventions.IERS_2010.getNutationArguments(ut1);
    for (double dt = -122000; dt < 54000; dt += 100) {
        final AbsoluteDate date = AbsoluteDate.J2000_EPOCH.shiftedBy(dt * Constants.JULIAN_YEAR);
        final BodiesElements el = fna.evaluateAll(date);
        for (int i = 1; i < tides.length; ++i) {
            Assert.assertTrue(tides[i - 1].getRate(el) < tides[i].getRate(el));
        }
    }
    // check we are in the expected species
    for (final Tide tide : tides) {
        Assert.assertEquals(tauMultiplier, tide.getTauMultiplier());
    }
}

Example 42 with TimeScale

use of org.orekit.time.TimeScale in project Orekit by CS-SI.

the class EclipticProviderTest method testAgreementWith406Ephemerides.

/**
 * Check the Ecliptic frame defined from IERS mean obliquity equations against the
 * position of Sun and Earth from the JPL 406 ephemerides.
 *
 * @throws Exception on error
 */
@Test
public void testAgreementWith406Ephemerides() throws Exception {
    TimeScale utc = TimeScalesFactory.getUTC();
    // time spans we have test data sets for.
    checkAlignment(new AbsoluteDate(1969, 5, 27, utc), new AbsoluteDate(1969, 9, 20, utc));
    checkAlignment(new AbsoluteDate(1969, 12, 5, utc), new AbsoluteDate(1970, 4, 1, utc));
    checkAlignment(new AbsoluteDate(1970, 6, 15, utc), new AbsoluteDate(1970, 8, 1, utc));
    checkAlignment(new AbsoluteDate(2002, 12, 16, utc), new AbsoluteDate(2004, 2, 3, utc));
    checkAlignment(new AbsoluteDate(1999, 11, 22, utc), new AbsoluteDate(2000, 5, 21, utc));
}

Example 43 with TimeScale

use of org.orekit.time.TimeScale in project Orekit by CS-SI.

the class TidalDisplacementTest method doTestDehant.

private void doTestDehant(final IERSConventions conventions, final boolean removePermanentDeformation, final boolean replaceModels, final double expectedDx, final double expectedDy, final double expectedDz, final double tolerance) throws OrekitException {
    Frame itrf = FramesFactory.getITRF(conventions, false);
    TimeScale ut1 = TimeScalesFactory.getUT1(conventions, false);
    final double re;
    final double sunEarthSystemMassRatio;
    final double earthMoonMassRatio;
    if (replaceModels) {
        // constants consistent with DEHANTTIDEINEL.F reference program
        // available at <ftp://tai.bipm.org/iers/conv2010/chapter7/dehanttideinel/>
        // and Copyright (C) 2008 IERS Conventions Center
        re = 6378136.6;
        final double massRatioSun = 332946.0482;
        final double massRatioMoon = 0.0123000371;
        sunEarthSystemMassRatio = massRatioSun * (1.0 / (1.0 + massRatioMoon));
        earthMoonMassRatio = 1.0 / massRatioMoon;
    } else {
        // constants consistent with IERS and JPL
        re = Constants.EIGEN5C_EARTH_EQUATORIAL_RADIUS;
        sunEarthSystemMassRatio = Constants.JPL_SSD_SUN_EARTH_PLUS_MOON_MASS_RATIO;
        earthMoonMassRatio = Constants.JPL_SSD_EARTH_MOON_MASS_RATIO;
    }
    // fake providers generating only the positions from the reference program test
    PVCoordinatesProvider fakeSun = (date, frame) -> new TimeStampedPVCoordinates(date, new Vector3D(137859926952.015, 54228127881.435, 23509422341.6960), Vector3D.ZERO, Vector3D.ZERO);
    PVCoordinatesProvider fakeMoon = (date, frame) -> new TimeStampedPVCoordinates(date, new Vector3D(-179996231.920342, -312468450.131567, -169288918.592160), Vector3D.ZERO, Vector3D.ZERO);
    TidalDisplacement td = new TidalDisplacement(re, sunEarthSystemMassRatio, earthMoonMassRatio, fakeSun, fakeMoon, conventions, removePermanentDeformation);
    FundamentalNutationArguments arguments = null;
    if (replaceModels) {
        try {
            // we override the official IERS conventions 2010 arguments with fake arguments matching DEHANTTIDEINEL.F code
            String regularArguments = "/assets/org/orekit/IERS-conventions/2010/nutation-arguments.txt";
            arguments = new FundamentalNutationArguments(conventions, ut1, IERSConventions.class.getResourceAsStream(regularArguments), regularArguments) {

                private static final long serialVersionUID = 20170913L;

                @Override
                public BodiesElements evaluateAll(final AbsoluteDate date) {
                    BodiesElements base = super.evaluateAll(date);
                    double fhr = date.getComponents(ut1).getTime().getSecondsInUTCDay() / 3600.0;
                    double t = base.getTC();
                    // Doodson fundamental arguments as per DEHANTTIDEINEL.F code
                    double s = 218.31664563 + (481267.88194 + (-0.0014663889 + (0.00000185139) * t) * t) * t;
                    double tau = fhr * 15 + 280.4606184 + (36000.7700536 + (0.00038793 + (-0.0000000258) * t) * t) * t - s;
                    double pr = (1.396971278 + (0.000308889 + (0.000000021 + (0.000000007) * t) * t) * t) * t;
                    double h = 280.46645 + (36000.7697489 + (0.00030322222 + (0.000000020 + (-0.00000000654) * t) * t) * t) * t;
                    double p = 83.35324312 + (4069.01363525 + (-0.01032172222 + (-0.0000124991 + (0.00000005263) * t) * t) * t) * t;
                    double zns = 234.95544499 + (1934.13626197 + (-0.00207561111 + (-0.00000213944 + (0.00000001650) * t) * t) * t) * t;
                    double ps = 282.93734098 + (1.71945766667 + (0.00045688889 + (-0.00000001778 + (-0.00000000334) * t) * t) * t) * t;
                    s += pr;
                    // rebuild Delaunay arguments from Doodson arguments, ignoring derivatives
                    return new BodiesElements(date, base.getTC(), FastMath.toRadians(s + tau), 0.0, FastMath.toRadians(s - p), 0.0, FastMath.toRadians(h - ps), 0.0, FastMath.toRadians(s + zns), 0.0, FastMath.toRadians(s - h), 0.0, FastMath.toRadians(-zns), 0.0, base.getLMe(), 0.0, base.getLVe(), 0.0, base.getLE(), 0.0, base.getLMa(), 0.0, base.getLJu(), 0.0, base.getLSa(), 0.0, base.getLUr(), 0.0, base.getLNe(), 0.0, base.getPa(), 0.0);
                }
            };
            // we override the official IERS conventions 2010 tides displacements with tides displacements matching DEHANTTIDEINEL.F code
            String table73a = "/tides/tab7.3a-Dehant.txt";
            Field diurnalCorrectionField = td.getClass().getDeclaredField("frequencyCorrectionDiurnal");
            diurnalCorrectionField.setAccessible(true);
            Method diurnalCorrectionGetter = IERSConventions.class.getDeclaredMethod("getTidalDisplacementFrequencyCorrectionDiurnal", String.class, Integer.TYPE, Integer.TYPE, Integer.TYPE, Integer.TYPE, Integer.TYPE);
            diurnalCorrectionGetter.setAccessible(true);
            diurnalCorrectionField.set(td, diurnalCorrectionGetter.invoke(null, table73a, 18, 15, 16, 17, 18));
        } catch (SecurityException | NoSuchMethodException | NoSuchFieldException | InvocationTargetException | IllegalArgumentException | IllegalAccessException e) {
            Assert.fail(e.getLocalizedMessage());
        }
    } else {
        arguments = conventions.getNutationArguments(ut1);
    }
    Vector3D fundamentalStationWettzell = new Vector3D(4075578.385, 931852.890, 4801570.154);
    AbsoluteDate date = new AbsoluteDate(2009, 4, 13, 0, 0, 0.0, ut1);
    Vector3D displacement = td.displacement(arguments.evaluateAll(date), itrf, fundamentalStationWettzell);
    Assert.assertEquals(expectedDx, displacement.getX(), tolerance);
    Assert.assertEquals(expectedDy, displacement.getY(), tolerance);
    Assert.assertEquals(expectedDz, displacement.getZ(), tolerance);
}

Example 44 with TimeScale

use of org.orekit.time.TimeScale in project Orekit by CS-SI.

the class OEMWriter method write.

/**
 * {@inheritDoc}
 */
@Override
public void write(final Appendable writer, final EphemerisFile ephemerisFile) throws OrekitException, IOException {
    if (writer == null) {
        throw new OrekitIllegalArgumentException(OrekitMessages.NULL_ARGUMENT, "writer");
    }
    if (ephemerisFile == null) {
        return;
    }
    final String idToProcess;
    if (spaceObjectId != null) {
        if (ephemerisFile.getSatellites().containsKey(spaceObjectId)) {
            idToProcess = spaceObjectId;
        } else {
            throw new OrekitIllegalArgumentException(OrekitMessages.VALUE_NOT_FOUND, spaceObjectId, "ephemerisFile");
        }
    } else if (ephemerisFile.getSatellites().keySet().size() == 1) {
        idToProcess = ephemerisFile.getSatellites().keySet().iterator().next();
    } else {
        throw new OrekitIllegalArgumentException(OrekitMessages.EPHEMERIS_FILE_NO_MULTI_SUPPORT);
    }
    // Get satellite and ephemeris segments to output.
    final EphemerisFile.SatelliteEphemeris satEphem = ephemerisFile.getSatellites().get(idToProcess);
    final List<? extends EphemerisSegment> segments = satEphem.getSegments();
    if (segments.isEmpty()) {
        // no data -> no output
        return;
    }
    final EphemerisSegment firstSegment = segments.get(0);
    final String objectName = this.spaceObjectName == null ? idToProcess : this.spaceObjectName;
    // Only one time scale per OEM file, see Section 5.2.4.5
    final TimeScale timeScale = firstSegment.getTimeScale();
    // metadata that is constant for the whole OEM file
    final Map<Keyword, String> metadata = new LinkedHashMap<>();
    metadata.put(Keyword.TIME_SYSTEM, firstSegment.getTimeScaleString());
    metadata.put(Keyword.ORIGINATOR, this.originator);
    // Only one object in an OEM file, see Section 2.1
    metadata.put(Keyword.OBJECT_ID, idToProcess);
    metadata.put(Keyword.OBJECT_NAME, objectName);
    metadata.put(Keyword.INTERPOLATION, this.interpolationMethod.toString());
    final StreamingOemWriter oemWriter = new StreamingOemWriter(writer, timeScale, metadata);
    oemWriter.writeHeader();
    for (final EphemerisSegment segment : segments) {
        // segment specific metadata
        metadata.clear();
        metadata.put(Keyword.CENTER_NAME, segment.getFrameCenterString());
        metadata.put(Keyword.REF_FRAME, segment.getFrameString());
        metadata.put(Keyword.START_TIME, segment.getStart().toString(timeScale));
        metadata.put(Keyword.STOP_TIME, segment.getStop().toString(timeScale));
        metadata.put(Keyword.INTERPOLATION_DEGREE, String.valueOf(segment.getInterpolationSamples() - 1));
        final Segment segmentWriter = oemWriter.newSegment(null, metadata);
        segmentWriter.writeMetadata();
        for (final TimeStampedPVCoordinates coordinates : segment.getCoordinates()) {
            segmentWriter.writeEphemerisLine(coordinates);
        }
    }
}

Example 45 with TimeScale

use of org.orekit.time.TimeScale in project Orekit by CS-SI.

the class FieldKeplerianPropagatorTest method doTestIssue107.

private <T extends RealFieldElement<T>> void doTestIssue107(Field<T> field) throws OrekitException {
    T zero = field.getZero();
    final TimeScale utc = TimeScalesFactory.getUTC();
    final FieldVector3D<T> position = new FieldVector3D<>(zero.add(-6142438.668), zero.add(3492467.56), zero.add(-25767.257));
    final FieldVector3D<T> velocity = new FieldVector3D<>(zero.add(505.848), zero.add(942.781), zero.add(7435.922));
    final FieldAbsoluteDate<T> date = new FieldAbsoluteDate<>(field, 2003, 9, 16, utc);
    final FieldOrbit<T> orbit = new FieldCircularOrbit<>(new FieldPVCoordinates<>(position, velocity), FramesFactory.getEME2000(), date, mu);
    FieldPropagator<T> propagator = new FieldKeplerianPropagator<T>(orbit) {

        FieldAbsoluteDate<T> lastDate = FieldAbsoluteDate.getPastInfinity(field);

        protected FieldSpacecraftState<T> basicPropagate(final FieldAbsoluteDate<T> date) throws OrekitException {
            if (date.compareTo(lastDate) < 0) {
                throw new OrekitException(LocalizedCoreFormats.SIMPLE_MESSAGE, "no backward propagation allowed");
            }
            lastDate = date;
            return super.basicPropagate(date);
        }
    };
    FieldSpacecraftState<T> finalState = propagator.propagate(date.shiftedBy(3600.0));
    Assert.assertEquals(3600.0, finalState.getDate().durationFrom(date).getReal(), 1.0e-15);
}