Examples with KeplerianPropagator org.orekit.propagation.analytical.KeplerianPropagator used on opensource projects

Example 31 with KeplerianPropagator

use of org.orekit.propagation.analytical.KeplerianPropagator in project Orekit by CS-SI.

the class OrekitEphemerisFileTest method testWritingToOEM.

@Test
public void testWritingToOEM() throws OrekitException, IOException {
    final double muTolerance = 1e-12;
    final double positionTolerance = 1e-8;
    final double velocityTolerance = 1e-8;
    final String satId = "SATELLITE1";
    final double sma = 10000000;
    final double inc = Math.toRadians(45.0);
    final double ecc = 0.001;
    final double raan = 0.0;
    final double pa = 0.0;
    final double ta = 0.0;
    final AbsoluteDate date = new AbsoluteDate();
    final Frame frame = FramesFactory.getGCRF();
    final CelestialBody body = CelestialBodyFactory.getEarth();
    final double mu = body.getGM();
    KeplerianOrbit initialOrbit = new KeplerianOrbit(sma, ecc, inc, pa, raan, ta, PositionAngle.TRUE, frame, date, mu);
    KeplerianPropagator propagator = new KeplerianPropagator(initialOrbit);
    final double propagationDurationSeconds = 86400.0;
    final double stepSizeSeconds = 60.0;
    List<SpacecraftState> states = new ArrayList<SpacecraftState>();
    for (double dt = 0.0; dt < propagationDurationSeconds; dt += stepSizeSeconds) {
        states.add(propagator.propagate(date.shiftedBy(dt)));
    }
    OrekitEphemerisFile ephemerisFile = new OrekitEphemerisFile();
    OrekitSatelliteEphemeris satellite = ephemerisFile.addSatellite(satId);
    satellite.addNewSegment(states);
    String tempOemFile = Files.createTempFile("OrekitEphemerisFileTest", ".oem").toString();
    new OEMWriter().write(tempOemFile, ephemerisFile);
    EphemerisFile ephemerisFromFile = new OEMParser().parse(tempOemFile);
    Files.delete(Paths.get(tempOemFile));
    EphemerisSegment segment = ephemerisFromFile.getSatellites().get(satId).getSegments().get(0);
    assertEquals(states.get(0).getDate(), segment.getStart());
    assertEquals(states.get(states.size() - 1).getDate(), segment.getStop());
    assertEquals(states.size(), segment.getCoordinates().size());
    assertEquals(frame, segment.getFrame());
    assertEquals(body.getName().toUpperCase(), segment.getFrameCenterString());
    assertEquals(body.getGM(), segment.getMu(), muTolerance);
    for (int i = 0; i < states.size(); i++) {
        TimeStampedPVCoordinates expected = states.get(i).getPVCoordinates();
        TimeStampedPVCoordinates actual = segment.getCoordinates().get(i);
        assertEquals(expected.getDate(), actual.getDate());
        assertEquals(0.0, Vector3D.distance(expected.getPosition(), actual.getPosition()), positionTolerance);
        assertEquals(0.0, Vector3D.distance(expected.getVelocity(), actual.getVelocity()), velocityTolerance);
    }
    // test ingested ephemeris generates access intervals
    final OneAxisEllipsoid parentShape = new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, FramesFactory.getITRF(IERSConventions.IERS_2010, true));
    final double latitude = 0.0;
    final double longitude = 0.0;
    final double altitude = 0.0;
    final GeodeticPoint point = new GeodeticPoint(latitude, longitude, altitude);
    final TopocentricFrame topo = new TopocentricFrame(parentShape, point, "testPoint1");
    final ElevationDetector elevationDetector = new ElevationDetector(topo);
    final EphemerisSegmentPropagator ephemerisSegmentPropagator = new EphemerisSegmentPropagator(segment);
    final EventsLogger lookupLogger = new EventsLogger();
    ephemerisSegmentPropagator.addEventDetector(lookupLogger.monitorDetector(elevationDetector));
    final EventsLogger referenceLogger = new EventsLogger();
    propagator.clearEventsDetectors();
    propagator.addEventDetector(referenceLogger.monitorDetector(elevationDetector));
    propagator.propagate(segment.getStart(), segment.getStop());
    ephemerisSegmentPropagator.propagate(segment.getStart(), segment.getStop());
    final double dateEpsilon = 1.0e-9;
    assertTrue(referenceLogger.getLoggedEvents().size() > 0);
    assertEquals(referenceLogger.getLoggedEvents().size(), lookupLogger.getLoggedEvents().size());
    for (int i = 0; i < referenceLogger.getLoggedEvents().size(); i++) {
        LoggedEvent reference = referenceLogger.getLoggedEvents().get(i);
        LoggedEvent actual = lookupLogger.getLoggedEvents().get(i);
        assertEquals(0.0, FastMath.abs(reference.getState().getDate().durationFrom(actual.getState().getDate())), dateEpsilon);
    }
    final Propagator embeddedPropagator = segment.getPropagator();
    final EventsLogger embeddedPropLogger = new EventsLogger();
    embeddedPropagator.addEventDetector(embeddedPropLogger.monitorDetector(elevationDetector));
    embeddedPropagator.propagate(segment.getStart(), segment.getStop());
    assertEquals(referenceLogger.getLoggedEvents().size(), embeddedPropLogger.getLoggedEvents().size());
    for (int i = 0; i < referenceLogger.getLoggedEvents().size(); i++) {
        LoggedEvent reference = referenceLogger.getLoggedEvents().get(i);
        LoggedEvent actual = embeddedPropLogger.getLoggedEvents().get(i);
        assertEquals(0.0, FastMath.abs(reference.getState().getDate().durationFrom(actual.getState().getDate())), dateEpsilon);
    }
    final List<SpacecraftState> readInStates = new ArrayList<SpacecraftState>();
    segment.getCoordinates().forEach(c -> {
        try {
            readInStates.add(new SpacecraftState(new CartesianOrbit(c, frame, mu)));
        } catch (IllegalArgumentException | OrekitException e) {
            fail(e.getLocalizedMessage());
        }
    });
    final int interpolationPoints = 5;
    Ephemeris directEphemProp = new Ephemeris(readInStates, interpolationPoints);
    final EventsLogger directEphemPropLogger = new EventsLogger();
    directEphemProp.addEventDetector(directEphemPropLogger.monitorDetector(elevationDetector));
    directEphemProp.propagate(segment.getStart(), segment.getStop());
    assertEquals(referenceLogger.getLoggedEvents().size(), directEphemPropLogger.getLoggedEvents().size());
    for (int i = 0; i < referenceLogger.getLoggedEvents().size(); i++) {
        LoggedEvent reference = referenceLogger.getLoggedEvents().get(i);
        LoggedEvent actual = directEphemPropLogger.getLoggedEvents().get(i);
        assertEquals(0.0, FastMath.abs(reference.getState().getDate().durationFrom(actual.getState().getDate())), dateEpsilon);
    }
}

Example 32 with KeplerianPropagator

use of org.orekit.propagation.analytical.KeplerianPropagator in project Orekit by CS-SI.

the class IntegratedEphemerisTest method testNormalKeplerIntegration.

@Test
public void testNormalKeplerIntegration() throws OrekitException {
    // Keplerian propagator definition
    KeplerianPropagator keplerEx = new KeplerianPropagator(initialOrbit);
    // Integrated ephemeris
    // Propagation
    AbsoluteDate finalDate = initialOrbit.getDate().shiftedBy(Constants.JULIAN_DAY);
    numericalPropagator.setEphemerisMode();
    numericalPropagator.setInitialState(new SpacecraftState(initialOrbit));
    numericalPropagator.propagate(finalDate);
    Assert.assertTrue(numericalPropagator.getCalls() < 3200);
    BoundedPropagator ephemeris = numericalPropagator.getGeneratedEphemeris();
    // tests
    for (int i = 1; i <= Constants.JULIAN_DAY; i++) {
        AbsoluteDate intermediateDate = initialOrbit.getDate().shiftedBy(i);
        SpacecraftState keplerIntermediateOrbit = keplerEx.propagate(intermediateDate);
        SpacecraftState numericIntermediateOrbit = ephemeris.propagate(intermediateDate);
        Vector3D kepPosition = keplerIntermediateOrbit.getPVCoordinates().getPosition();
        Vector3D numPosition = numericIntermediateOrbit.getPVCoordinates().getPosition();
        Assert.assertEquals(0, kepPosition.subtract(numPosition).getNorm(), 0.06);
    }
    // test inv
    AbsoluteDate intermediateDate = initialOrbit.getDate().shiftedBy(41589);
    SpacecraftState keplerIntermediateOrbit = keplerEx.propagate(intermediateDate);
    SpacecraftState state = keplerEx.propagate(finalDate);
    numericalPropagator.setInitialState(state);
    numericalPropagator.setEphemerisMode();
    numericalPropagator.propagate(initialOrbit.getDate());
    BoundedPropagator invEphemeris = numericalPropagator.getGeneratedEphemeris();
    SpacecraftState numericIntermediateOrbit = invEphemeris.propagate(intermediateDate);
    Vector3D kepPosition = keplerIntermediateOrbit.getPVCoordinates().getPosition();
    Vector3D numPosition = numericIntermediateOrbit.getPVCoordinates().getPosition();
    Assert.assertEquals(0, kepPosition.subtract(numPosition).getNorm(), 10e-2);
}

Example 33 with KeplerianPropagator

use of org.orekit.propagation.analytical.KeplerianPropagator in project Orekit by CS-SI.

the class EventDetectorTest method testIssue108Analytical.

@Test
public void testIssue108Analytical() throws OrekitException {
    final TimeScale utc = TimeScalesFactory.getUTC();
    final Vector3D position = new Vector3D(-6142438.668, 3492467.56, -25767.257);
    final Vector3D velocity = new Vector3D(505.848, 942.781, 7435.922);
    final AbsoluteDate date = new AbsoluteDate(2003, 9, 16, utc);
    final Orbit orbit = new CircularOrbit(new PVCoordinates(position, velocity), FramesFactory.getEME2000(), date, mu);
    final double step = 60.0;
    final int n = 100;
    KeplerianPropagator propagator = new KeplerianPropagator(orbit);
    GCallsCounter counter = new GCallsCounter(100000.0, 1.0e-6, 20, new StopOnEvent<GCallsCounter>());
    propagator.addEventDetector(counter);
    propagator.setMasterMode(step, new OrekitFixedStepHandler() {

        public void handleStep(SpacecraftState currentState, boolean isLast) {
        }
    });
    propagator.propagate(date.shiftedBy(n * step));
    Assert.assertEquals(n + 1, counter.getCount());
}

Example 34 with KeplerianPropagator

use of org.orekit.propagation.analytical.KeplerianPropagator in project Orekit by CS-SI.

the class EventDetectorTest method testNoisyGFunction.

@Test
public void testNoisyGFunction() throws OrekitException {
    // initial conditions
    Frame eme2000 = FramesFactory.getEME2000();
    TimeScale utc = TimeScalesFactory.getUTC();
    AbsoluteDate initialDate = new AbsoluteDate(2011, 5, 11, utc);
    AbsoluteDate startDate = new AbsoluteDate(2032, 10, 17, utc);
    AbsoluteDate interruptDate = new AbsoluteDate(2032, 10, 18, utc);
    AbsoluteDate targetDate = new AbsoluteDate(2211, 5, 11, utc);
    KeplerianPropagator k1 = new KeplerianPropagator(new EquinoctialOrbit(new PVCoordinates(new Vector3D(4008462.4706055815, -3155502.5373837613, -5044275.9880020910), new Vector3D(-5012.9298276860990, 1920.3567095973078, -5172.7403501801580)), eme2000, initialDate, Constants.WGS84_EARTH_MU));
    KeplerianPropagator k2 = new KeplerianPropagator(new EquinoctialOrbit(new PVCoordinates(new Vector3D(4008912.4039522274, -3155453.3125615157, -5044297.6484738905), new Vector3D(-5012.5883854112530, 1920.6332221785074, -5172.2177085540500)), eme2000, initialDate, Constants.WGS84_EARTH_MU));
    k2.addEventDetector(new CloseApproachDetector(2015.243454166727, 0.0001, 100, new ContinueOnEvent<CloseApproachDetector>(), k1));
    k2.addEventDetector(new DateDetector(Constants.JULIAN_DAY, 1.0e-6, interruptDate));
    SpacecraftState s = k2.propagate(startDate, targetDate);
    Assert.assertEquals(0.0, interruptDate.durationFrom(s.getDate()), 1.1e-6);
}

Example 35 with KeplerianPropagator

use of org.orekit.propagation.analytical.KeplerianPropagator in project Orekit by CS-SI.

the class FieldOfViewDetectorTest method testStopOnExit.

/**
 * check the default behavior to stop propagation on FoV exit.
 */
@Test
public void testStopOnExit() throws OrekitException {
    // setup
    double pi = FastMath.PI;
    // arbitrary date
    AbsoluteDate date = AbsoluteDate.J2000_EPOCH;
    AbsoluteDate endDate = date.shiftedBy(Constants.JULIAN_DAY);
    Frame eci = FramesFactory.getGCRF();
    Frame ecef = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
    BodyShape earth = new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, ecef);
    GeodeticPoint gp = new GeodeticPoint(FastMath.toRadians(39), FastMath.toRadians(77), 0);
    TopocentricFrame topo = new TopocentricFrame(earth, gp, "topo");
    // iss like orbit
    KeplerianOrbit orbit = new KeplerianOrbit(6378137 + 400e3, 0, FastMath.toRadians(51.65), 0, 0, 0, PositionAngle.TRUE, eci, date, Constants.EGM96_EARTH_MU);
    AttitudeProvider attitude = new NadirPointing(eci, earth);
    // action
    FieldOfView fov = new FieldOfView(Vector3D.PLUS_K, Vector3D.PLUS_I, pi / 3, 16, 0);
    FieldOfViewDetector fovDetector = new FieldOfViewDetector(topo, fov).withMaxCheck(5.0);
    EventsLogger logger = new EventsLogger();
    Propagator prop = new KeplerianPropagator(orbit, attitude);
    prop.addEventDetector(logger.monitorDetector(fovDetector));
    prop.propagate(endDate);
    List<LoggedEvent> actual = logger.getLoggedEvents();
    // verify
    // check we have an entry and an exit event.
    Assert.assertEquals(2, actual.size());
}