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

Example 1 with KeplerianPropagator

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

the class ImpulseManeuverTest method testBackward.

@Test
public void testBackward() throws OrekitException {
    final AbsoluteDate iniDate = new AbsoluteDate(2003, 5, 1, 17, 30, 0.0, TimeScalesFactory.getUTC());
    final Orbit initialOrbit = new KeplerianOrbit(7e6, 1.0e-4, FastMath.toRadians(98.5), FastMath.toRadians(87.0), FastMath.toRadians(216.1807), FastMath.toRadians(319.779), PositionAngle.MEAN, FramesFactory.getEME2000(), iniDate, Constants.EIGEN5C_EARTH_MU);
    KeplerianPropagator propagator = new KeplerianPropagator(initialOrbit, new LofOffset(initialOrbit.getFrame(), LOFType.VNC));
    DateDetector dateDetector = new DateDetector(iniDate.shiftedBy(-300));
    Vector3D deltaV = new Vector3D(12.0, 1.0, -4.0);
    final double isp = 300;
    ImpulseManeuver<DateDetector> maneuver = new ImpulseManeuver<DateDetector>(dateDetector, deltaV, isp).withMaxCheck(3600.0).withThreshold(1.0e-6);
    propagator.addEventDetector(maneuver);
    SpacecraftState finalState = propagator.propagate(initialOrbit.getDate().shiftedBy(-900));
    Assert.assertTrue(finalState.getMass() > propagator.getInitialState().getMass());
    Assert.assertTrue(finalState.getDate().compareTo(propagator.getInitialState().getDate()) < 0);
}

Example 2 with KeplerianPropagator

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

the class TopocentricFrameTest method testDoppler.

@Test
public void testDoppler() throws OrekitException {
    // Surface point at latitude 45, longitude 5
    final GeodeticPoint point = new GeodeticPoint(FastMath.toRadians(45.), FastMath.toRadians(5.), 0.);
    final TopocentricFrame topoFrame = new TopocentricFrame(earthSpheric, point, "lon 5 lat 45");
    // Point at 30 deg longitude
    // ***************************
    final CircularOrbit orbit = new CircularOrbit(7178000.0, 0.5e-8, -0.5e-8, FastMath.toRadians(50.), FastMath.toRadians(120.), FastMath.toRadians(90.), PositionAngle.MEAN, FramesFactory.getEME2000(), date, mu);
    // Transform satellite position to position/velocity parameters in body frame
    final Transform eme2000ToItrf = FramesFactory.getEME2000().getTransformTo(earthSpheric.getBodyFrame(), date);
    final PVCoordinates pvSatItrf = eme2000ToItrf.transformPVCoordinates(orbit.getPVCoordinates());
    // Compute range rate directly
    // ********************************************
    final double dop = topoFrame.getRangeRate(pvSatItrf, earthSpheric.getBodyFrame(), date);
    // Compare to finite difference computation (2 points)
    // *****************************************************
    final double dt = 0.1;
    KeplerianPropagator extrapolator = new KeplerianPropagator(orbit);
    // Extrapolate satellite position a short while after reference date
    AbsoluteDate dateP = date.shiftedBy(dt);
    Transform j2000ToItrfP = FramesFactory.getEME2000().getTransformTo(earthSpheric.getBodyFrame(), dateP);
    SpacecraftState orbitP = extrapolator.propagate(dateP);
    Vector3D satPointGeoP = j2000ToItrfP.transformPVCoordinates(orbitP.getPVCoordinates()).getPosition();
    // Retropolate satellite position a short while before reference date
    AbsoluteDate dateM = date.shiftedBy(-dt);
    Transform j2000ToItrfM = FramesFactory.getEME2000().getTransformTo(earthSpheric.getBodyFrame(), dateM);
    SpacecraftState orbitM = extrapolator.propagate(dateM);
    Vector3D satPointGeoM = j2000ToItrfM.transformPVCoordinates(orbitM.getPVCoordinates()).getPosition();
    // Compute ranges at both instants
    double rangeP = topoFrame.getRange(satPointGeoP, earthSpheric.getBodyFrame(), dateP);
    double rangeM = topoFrame.getRange(satPointGeoM, earthSpheric.getBodyFrame(), dateM);
    final double dopRef2 = (rangeP - rangeM) / (2. * dt);
    Assert.assertEquals(dopRef2, dop, 1.e-3);
}

Example 3 with KeplerianPropagator

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

the class FiniteDifferencePropagatorConverterTest method testGetObjectiveFunctionParametersOnlyScaledOnce.

/**
 * Test case for bug #362. Check that scaling is only applied once.
 *
 * @throws OrekitException on error.
 */
@Test
public void testGetObjectiveFunctionParametersOnlyScaledOnce() throws OrekitException {
    // setup
    // create some arbitrary sample data to run with
    Frame eci = FramesFactory.getGCRF();
    double gm = Constants.EIGEN5C_EARTH_MU;
    AbsoluteDate date = AbsoluteDate.J2000_EPOCH;
    Propagator source = new KeplerianPropagator(new KeplerianOrbit(6878137, 0, 0, 0, 0, 0, PositionAngle.TRUE, eci, date, gm));
    // Create a mock builder that allows us to check the values passed to it
    PropagatorBuilder builder = Mockito.mock(PropagatorBuilder.class);
    ParameterDriversList list = new ParameterDriversList();
    list.add(new ParameterDriver("p1", 0, 1e-3, Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY));
    Mockito.when(builder.getOrbitalParametersDrivers()).thenReturn(list);
    Mockito.when(builder.getPropagationParametersDrivers()).thenReturn(new ParameterDriversList());
    Mockito.when(builder.getFrame()).thenReturn(eci);
    Mockito.when(builder.getSelectedNormalizedParameters()).thenReturn(new double[1]);
    Mockito.when(builder.buildPropagator(Mockito.any(double[].class))).thenReturn(source);
    // subject under test
    FiniteDifferencePropagatorConverter converter = new FiniteDifferencePropagatorConverter(builder, 1, 100);
    // set some internal variables in FDPC that are not settable using another
    // interface
    converter.convert(source, 1, 2);
    // Forget all the side effect of the call to convert()
    Mockito.clearInvocations(builder);
    // action
    converter.getModel().value(new ArrayRealVector(1));
    // verify
    Mockito.verify(builder).buildPropagator(new double[] { 0 });
    Mockito.verify(builder).buildPropagator(new double[] { 1 });
}

Example 4 with KeplerianPropagator

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

the class KeplerianConverterTest method checkFit.

protected void checkFit(final Orbit orbit, final double duration, final double stepSize, final double threshold, final boolean positionOnly, final double expectedRMS, final String... freeParameters) throws OrekitException {
    Propagator p = new KeplerianPropagator(orbit);
    List<SpacecraftState> sample = new ArrayList<SpacecraftState>();
    for (double dt = 0; dt < duration; dt += stepSize) {
        sample.add(p.propagate(orbit.getDate().shiftedBy(dt)));
    }
    PropagatorBuilder builder = new KeplerianPropagatorBuilder(OrbitType.KEPLERIAN.convertType(orbit), PositionAngle.MEAN, 1.0);
    FiniteDifferencePropagatorConverter fitter = new FiniteDifferencePropagatorConverter(builder, threshold, 1000);
    fitter.convert(sample, positionOnly, freeParameters);
    Assert.assertEquals(expectedRMS, fitter.getRMS(), 0.01 * expectedRMS);
    KeplerianPropagator prop = (KeplerianPropagator) fitter.getAdaptedPropagator();
    Orbit fitted = prop.getInitialState().getOrbit();
    final double eps = 1.0e-12;
    Assert.assertEquals(orbit.getPVCoordinates().getPosition().getX(), fitted.getPVCoordinates().getPosition().getX(), eps * orbit.getPVCoordinates().getPosition().getX());
    Assert.assertEquals(orbit.getPVCoordinates().getPosition().getY(), fitted.getPVCoordinates().getPosition().getY(), eps * orbit.getPVCoordinates().getPosition().getY());
    Assert.assertEquals(orbit.getPVCoordinates().getPosition().getZ(), fitted.getPVCoordinates().getPosition().getZ(), eps * orbit.getPVCoordinates().getPosition().getZ());
    Assert.assertEquals(orbit.getPVCoordinates().getVelocity().getX(), fitted.getPVCoordinates().getVelocity().getX(), -eps * orbit.getPVCoordinates().getVelocity().getX());
    Assert.assertEquals(orbit.getPVCoordinates().getVelocity().getY(), fitted.getPVCoordinates().getVelocity().getY(), eps * orbit.getPVCoordinates().getVelocity().getY());
    Assert.assertEquals(orbit.getPVCoordinates().getVelocity().getZ(), fitted.getPVCoordinates().getVelocity().getZ(), eps * orbit.getPVCoordinates().getVelocity().getZ());
}

Example 5 with KeplerianPropagator

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

the class ElevationDetectorTest method testIssue110.

@Test
public void testIssue110() throws OrekitException {
    // KEPLERIAN PROPAGATOR
    final Frame eme2000Frame = FramesFactory.getEME2000();
    final AbsoluteDate initDate = AbsoluteDate.J2000_EPOCH;
    final double a = 7000000.0;
    final Orbit initialOrbit = new KeplerianOrbit(a, 0.0, FastMath.PI / 2.2, 0.0, FastMath.PI / 2., 0.0, PositionAngle.TRUE, eme2000Frame, initDate, Constants.EGM96_EARTH_MU);
    final KeplerianPropagator kProp = new KeplerianPropagator(initialOrbit);
    // earth shape
    final OneAxisEllipsoid earthShape = new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, FramesFactory.getITRF(IERSConventions.IERS_2010, true));
    // Ground station
    final GeodeticPoint stat = new GeodeticPoint(FastMath.toRadians(35.), FastMath.toRadians(149.8), 0.);
    final TopocentricFrame station = new TopocentricFrame(earthShape, stat, "GSTATION");
    // detector creation
    // =================
    final double maxCheck = 600.;
    final double threshold = 1.0e-3;
    final EventDetector rawEvent = new ElevationDetector(maxCheck, threshold, station).withConstantElevation(FastMath.toRadians(5.0)).withHandler(new ContinueOnEvent<ElevationDetector>());
    final EventsLogger logger = new EventsLogger();
    kProp.addEventDetector(logger.monitorDetector(rawEvent));
    // PROPAGATION with DETECTION
    final AbsoluteDate finalDate = initDate.shiftedBy(30 * 60.);
    kProp.propagate(finalDate);
    Assert.assertEquals(2, logger.getLoggedEvents().size());
    Assert.assertTrue(logger.getLoggedEvents().get(0).isIncreasing());
    Assert.assertEquals(478.945, logger.getLoggedEvents().get(0).getState().getDate().durationFrom(initDate), 1.0e-3);
    Assert.assertFalse(logger.getLoggedEvents().get(1).isIncreasing());
    Assert.assertEquals(665.721, logger.getLoggedEvents().get(1).getState().getDate().durationFrom(initDate), 1.0e-3);
}