Examples with UnnormalizedSphericalHarmonicsProvider org.orekit.forces.gravity.potential.UnnormalizedSphericalHarmonicsProvider used on opensource projects

Example 11 with UnnormalizedSphericalHarmonicsProvider

use of org.orekit.forces.gravity.potential.UnnormalizedSphericalHarmonicsProvider in project Orekit by CS-SI.

the class DSSTPropagatorTest method testMeanToOsculatingState.

@Test
public void testMeanToOsculatingState() throws IllegalArgumentException, OrekitException {
    final SpacecraftState meanState = getGEOState();
    final UnnormalizedSphericalHarmonicsProvider provider = GravityFieldFactory.getUnnormalizedProvider(2, 0);
    final Frame earthFrame = CelestialBodyFactory.getEarth().getBodyOrientedFrame();
    final DSSTForceModel zonal = new DSSTZonal(provider, 2, 1, 5);
    final DSSTForceModel tesseral = new DSSTTesseral(earthFrame, Constants.WGS84_EARTH_ANGULAR_VELOCITY, provider, 2, 0, 0, 2, 2, 0, 0);
    final Collection<DSSTForceModel> forces = new ArrayList<DSSTForceModel>();
    forces.add(zonal);
    forces.add(tesseral);
    final SpacecraftState osculatingState = DSSTPropagator.computeOsculatingState(meanState, null, forces);
    Assert.assertEquals(1559.1, Vector3D.distance(meanState.getPVCoordinates().getPosition(), osculatingState.getPVCoordinates().getPosition()), 1.0);
}

Example 12 with UnnormalizedSphericalHarmonicsProvider

use of org.orekit.forces.gravity.potential.UnnormalizedSphericalHarmonicsProvider in project Orekit by CS-SI.

the class DSSTPropagatorTest method testHighDegreesSetting.

@Test
public void testHighDegreesSetting() throws OrekitException {
    Utils.setDataRoot("regular-data:potential/grgs-format");
    GravityFieldFactory.addPotentialCoefficientsReader(new GRGSFormatReader("grim4s4_gr", true));
    int earthDegree = 36;
    int earthOrder = 36;
    int eccPower = 4;
    final UnnormalizedSphericalHarmonicsProvider provider = GravityFieldFactory.getUnnormalizedProvider(earthDegree, earthOrder);
    final org.orekit.frames.Frame earthFrame = // terrestrial frame
    FramesFactory.getITRF(IERSConventions.IERS_2010, true);
    final DSSTForceModel force = new DSSTTesseral(earthFrame, Constants.WGS84_EARTH_ANGULAR_VELOCITY, provider, earthDegree, earthOrder, eccPower, earthDegree + eccPower, earthDegree, earthOrder, eccPower);
    final Collection<DSSTForceModel> forces = new ArrayList<DSSTForceModel>();
    forces.add(force);
    TimeScale tai = TimeScalesFactory.getTAI();
    AbsoluteDate initialDate = new AbsoluteDate("2015-07-01", tai);
    Frame eci = FramesFactory.getGCRF();
    KeplerianOrbit orbit = new KeplerianOrbit(7120000.0, 1.0e-3, FastMath.toRadians(60.0), FastMath.toRadians(120.0), FastMath.toRadians(47.0), FastMath.toRadians(12.0), PositionAngle.TRUE, eci, initialDate, Constants.EIGEN5C_EARTH_MU);
    SpacecraftState oscuState = DSSTPropagator.computeOsculatingState(new SpacecraftState(orbit), null, forces);
    Assert.assertEquals(7119927.097122, oscuState.getA(), 0.001);
}

Example 13 with UnnormalizedSphericalHarmonicsProvider

use of org.orekit.forces.gravity.potential.UnnormalizedSphericalHarmonicsProvider in project Orekit by CS-SI.

the class DSSTPropagatorTest method testGetInitialOsculatingState.

@Test
public void testGetInitialOsculatingState() throws IllegalArgumentException, OrekitException {
    final SpacecraftState initialState = getGEOState();
    // build integrator
    final double minStep = initialState.getKeplerianPeriod() * 0.1;
    final double maxStep = initialState.getKeplerianPeriod() * 10.0;
    final double[][] tol = DSSTPropagator.tolerances(0.1, initialState.getOrbit());
    AdaptiveStepsizeIntegrator integrator = new DormandPrince853Integrator(minStep, maxStep, tol[0], tol[1]);
    // build the propagator for the propagation of the mean elements
    DSSTPropagator prop = new DSSTPropagator(integrator, true);
    final UnnormalizedSphericalHarmonicsProvider provider = GravityFieldFactory.getUnnormalizedProvider(4, 0);
    final Frame earthFrame = CelestialBodyFactory.getEarth().getBodyOrientedFrame();
    DSSTForceModel zonal = new DSSTZonal(provider, 4, 3, 9);
    DSSTForceModel tesseral = new DSSTTesseral(earthFrame, Constants.WGS84_EARTH_ANGULAR_VELOCITY, provider, 4, 0, 4, 8, 4, 0, 2);
    prop.addForceModel(zonal);
    prop.addForceModel(tesseral);
    // Set the initial state as osculating
    prop.setInitialState(initialState, false);
    // Check the stored initial state is the osculating one
    Assert.assertEquals(initialState, prop.getInitialState());
    // Check that no propagation, i.e. propagation to the initial date, provides the initial
    // osculating state although the propagator is configured to propagate mean elements !!!
    Assert.assertEquals(initialState, prop.propagate(initialState.getDate()));
}

Example 14 with UnnormalizedSphericalHarmonicsProvider

use of org.orekit.forces.gravity.potential.UnnormalizedSphericalHarmonicsProvider in project Orekit by CS-SI.

the class IntegratedEphemerisTest method doTestSerializationDSST.

private void doTestSerializationDSST(boolean meanOnly, int expectedSize) throws OrekitException, IOException, ClassNotFoundException {
    AbsoluteDate finalDate = initialOrbit.getDate().shiftedBy(Constants.JULIAN_DAY);
    final double[][] tol = DSSTPropagator.tolerances(1.0, initialOrbit);
    AdaptiveStepsizeIntegrator integrator = new DormandPrince853Integrator(10, Constants.JULIAN_DAY, tol[0], tol[1]);
    DSSTPropagator dsstProp = new DSSTPropagator(integrator, meanOnly);
    dsstProp.setInitialState(new SpacecraftState(initialOrbit), false);
    dsstProp.setEphemerisMode();
    final Frame itrf = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
    final UnnormalizedSphericalHarmonicsProvider gravity = GravityFieldFactory.getUnnormalizedProvider(8, 8);
    final CelestialBody sun = CelestialBodyFactory.getSun();
    final CelestialBody moon = CelestialBodyFactory.getMoon();
    final RadiationSensitive spacecraft = new IsotropicRadiationSingleCoefficient(20.0, 2.0);
    dsstProp.addForceModel(new DSSTZonal(gravity, 8, 7, 17));
    dsstProp.addForceModel(new DSSTTesseral(itrf, Constants.WGS84_EARTH_ANGULAR_VELOCITY, gravity, 8, 8, 4, 12, 8, 8, 4));
    dsstProp.addForceModel(new DSSTThirdBody(sun));
    dsstProp.addForceModel(new DSSTThirdBody(moon));
    dsstProp.addForceModel(new DSSTSolarRadiationPressure(sun, Constants.WGS84_EARTH_EQUATORIAL_RADIUS, spacecraft));
    dsstProp.propagate(finalDate);
    IntegratedEphemeris ephemeris = (IntegratedEphemeris) dsstProp.getGeneratedEphemeris();
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    ObjectOutputStream oos = new ObjectOutputStream(bos);
    oos.writeObject(ephemeris);
    Assert.assertTrue("size = " + bos.size(), bos.size() > 9 * expectedSize / 10);
    Assert.assertTrue("size = " + bos.size(), bos.size() < 11 * expectedSize / 10);
    Assert.assertNotNull(ephemeris.getFrame());
    Assert.assertSame(ephemeris.getFrame(), dsstProp.getFrame());
    ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
    ObjectInputStream ois = new ObjectInputStream(bis);
    IntegratedEphemeris deserialized = (IntegratedEphemeris) ois.readObject();
    Assert.assertEquals(deserialized.getMinDate(), deserialized.getMinDate());
    Assert.assertEquals(deserialized.getMaxDate(), deserialized.getMaxDate());
}

Example 15 with UnnormalizedSphericalHarmonicsProvider

use of org.orekit.forces.gravity.potential.UnnormalizedSphericalHarmonicsProvider in project Orekit by CS-SI.

the class FieldEcksteinHechlerPropagatorTest method doAlmostSphericalBody.

private <T extends RealFieldElement<T>> void doAlmostSphericalBody(Field<T> field) throws OrekitException {
    T zero = field.getZero();
    FieldAbsoluteDate<T> date = new FieldAbsoluteDate<>(field);
    // Definition of initial conditions
    // ---------------------------------
    // with e around e = 1.4e-4 and i = 1.7 rad
    FieldVector3D<T> position = new FieldVector3D<>(zero.add(3220103.), zero.add(69623.), zero.add(6449822.));
    FieldVector3D<T> velocity = new FieldVector3D<>(zero.add(6414.7), zero.add(-2006.), zero.add(-3180.));
    FieldAbsoluteDate<T> initDate = date.shiftedBy(584.);
    FieldOrbit<T> initialOrbit = new FieldEquinoctialOrbit<>(new FieldPVCoordinates<>(position, velocity), FramesFactory.getEME2000(), initDate, provider.getMu());
    // Initialisation to simulate a Keplerian extrapolation
    // To be noticed: in order to simulate a Keplerian extrapolation with the
    // analytical
    // extrapolator, one should put the zonal coefficients to 0. But due to
    // numerical pbs
    // one must put a non 0 value.
    UnnormalizedSphericalHarmonicsProvider kepProvider = GravityFieldFactory.getUnnormalizedProvider(6.378137e6, 3.9860047e14, TideSystem.UNKNOWN, new double[][] { { 0 }, { 0 }, { 0.1e-10 }, { 0.1e-13 }, { 0.1e-13 }, { 0.1e-14 }, { 0.1e-14 } }, new double[][] { { 0 }, { 0 }, { 0 }, { 0 }, { 0 }, { 0 }, { 0 } });
    // Extrapolators definitions
    // -------------------------
    FieldEcksteinHechlerPropagator<T> extrapolatorAna = new FieldEcksteinHechlerPropagator<>(initialOrbit, kepProvider);
    FieldKeplerianPropagator<T> extrapolatorKep = new FieldKeplerianPropagator<>(initialOrbit);
    // Extrapolation at a final date different from initial date
    // ---------------------------------------------------------
    // extrapolation duration in seconds
    double delta_t = 100.0;
    FieldAbsoluteDate<T> extrapDate = initDate.shiftedBy(delta_t);
    FieldSpacecraftState<T> finalOrbitAna = extrapolatorAna.propagate(extrapDate);
    FieldSpacecraftState<T> finalOrbitKep = extrapolatorKep.propagate(extrapDate);
    Assert.assertEquals(finalOrbitAna.getDate().durationFrom(extrapDate).getReal(), 0.0, Utils.epsilonTest);
    // comparison of each orbital parameters
    Assert.assertEquals(finalOrbitAna.getA().getReal(), finalOrbitKep.getA().getReal(), 10 * Utils.epsilonTest * finalOrbitKep.getA().getReal());
    Assert.assertEquals(finalOrbitAna.getEquinoctialEx().getReal(), finalOrbitKep.getEquinoctialEx().getReal(), Utils.epsilonE * finalOrbitKep.getE().getReal());
    Assert.assertEquals(finalOrbitAna.getEquinoctialEy().getReal(), finalOrbitKep.getEquinoctialEy().getReal(), Utils.epsilonE * finalOrbitKep.getE().getReal());
    Assert.assertEquals(MathUtils.normalizeAngle(finalOrbitAna.getHx().getReal(), finalOrbitKep.getHx().getReal()), finalOrbitKep.getHx().getReal(), Utils.epsilonAngle * FastMath.abs(finalOrbitKep.getI().getReal()));
    Assert.assertEquals(MathUtils.normalizeAngle(finalOrbitAna.getHy().getReal(), finalOrbitKep.getHy().getReal()), finalOrbitKep.getHy().getReal(), Utils.epsilonAngle * FastMath.abs(finalOrbitKep.getI().getReal()));
    Assert.assertEquals(MathUtils.normalizeAngle(finalOrbitAna.getLv().getReal(), finalOrbitKep.getLv().getReal()), finalOrbitKep.getLv().getReal(), Utils.epsilonAngle * FastMath.abs(finalOrbitKep.getLv().getReal()));
    Assert.assertEquals(MathUtils.normalizeAngle(finalOrbitAna.getLE().getReal(), finalOrbitKep.getLE().getReal()), finalOrbitKep.getLE().getReal(), Utils.epsilonAngle * FastMath.abs(finalOrbitKep.getLE().getReal()));
    Assert.assertEquals(MathUtils.normalizeAngle(finalOrbitAna.getLM().getReal(), finalOrbitKep.getLM().getReal()), finalOrbitKep.getLM().getReal(), Utils.epsilonAngle * FastMath.abs(finalOrbitKep.getLM().getReal()));
}