Examples with KeplerianOrbit org.orekit.orbits.KeplerianOrbit used on opensource projects

Example 6 with KeplerianOrbit

use of org.orekit.orbits.KeplerianOrbit in project Orekit by CS-SI.

the class MarshallSolarActivityFutureEstimationTest method testWithPropagator.

/**
 * Check integration error is small when integrating the same equations over the same
 * interval.
 *
 * @throws OrekitException on error.
 */
@Test
public void testWithPropagator() throws OrekitException {
    CelestialBody sun = CelestialBodyFactory.getSun();
    final Frame eci = FramesFactory.getGCRF();
    final Frame ecef = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
    AbsoluteDate date = new AbsoluteDate(2004, 1, 1, utc);
    OneAxisEllipsoid earth = new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, ecef);
    Orbit orbit = new KeplerianOrbit(6378137 + 400e3, 1e-3, FastMath.toRadians(50), 0, 0, 0, PositionAngle.TRUE, eci, date, Constants.EIGEN5C_EARTH_MU);
    final SpacecraftState ic = new SpacecraftState(orbit);
    final AbsoluteDate end = date.shiftedBy(5 * Constants.JULIAN_DAY);
    final AbsoluteDate resetDate = date.shiftedBy(0.8 * Constants.JULIAN_DAY + 0.1);
    final SpacecraftState[] lastState = new SpacecraftState[1];
    final OrekitStepHandler stepSaver = (interpolator, isLast) -> {
        final AbsoluteDate start = interpolator.getPreviousState().getDate();
        if (start.compareTo(resetDate) < 0) {
            lastState[0] = interpolator.getPreviousState();
        }
    };
    // propagate with state rest to take slightly different path
    NumericalPropagator propagator = getNumericalPropagator(sun, earth, ic);
    propagator.setMasterMode(stepSaver);
    propagator.propagate(resetDate);
    propagator.resetInitialState(lastState[0]);
    propagator.setSlaveMode();
    final SpacecraftState actual = propagator.propagate(end);
    // propagate straight through
    propagator = getNumericalPropagator(sun, earth, ic);
    propagator.resetInitialState(ic);
    propagator.setSlaveMode();
    final SpacecraftState expected = propagator.propagate(end);
    assertThat(actual.getPVCoordinates(), pvCloseTo(expected.getPVCoordinates(), 1.0));
}

Example 7 with KeplerianOrbit

use of org.orekit.orbits.KeplerianOrbit in project Orekit by CS-SI.

the class HolmesFeatherstoneAttractionModelTest method testStateJacobianVs80Implementation.

@Test
public void testStateJacobianVs80Implementation() throws OrekitException {
    Utils.setDataRoot("regular-data:potential/grgs-format");
    GravityFieldFactory.addPotentialCoefficientsReader(new GRGSFormatReader("grim4s4_gr", true));
    // initialization
    AbsoluteDate date = new AbsoluteDate(new DateComponents(2000, 07, 01), new TimeComponents(13, 59, 27.816), TimeScalesFactory.getUTC());
    double i = FastMath.toRadians(98.7);
    double omega = FastMath.toRadians(93.0);
    double OMEGA = FastMath.toRadians(15.0 * 22.5);
    Orbit orbit = new KeplerianOrbit(7201009.7124401, 1e-3, i, omega, OMEGA, 0, PositionAngle.MEAN, FramesFactory.getEME2000(), date, mu);
    HolmesFeatherstoneAttractionModel hfModel = new HolmesFeatherstoneAttractionModel(itrf, GravityFieldFactory.getNormalizedProvider(50, 50));
    Assert.assertEquals(TideSystem.UNKNOWN, hfModel.getTideSystem());
    SpacecraftState state = new SpacecraftState(orbit);
    checkStateJacobianVs80Implementation(state, hfModel, new LofOffset(state.getFrame(), LOFType.VVLH), 2.0e-15, false);
}

Example 8 with KeplerianOrbit

use of org.orekit.orbits.KeplerianOrbit in project Orekit by CS-SI.

the class HolmesFeatherstoneAttractionModelTest method testHelioSynchronous.

// rough test to determine if J2 alone creates heliosynchronism
@Test
public void testHelioSynchronous() throws OrekitException {
    // initialization
    AbsoluteDate date = new AbsoluteDate(new DateComponents(1970, 07, 01), new TimeComponents(13, 59, 27.816), TimeScalesFactory.getUTC());
    Transform itrfToEME2000 = itrf.getTransformTo(FramesFactory.getEME2000(), date);
    Vector3D pole = itrfToEME2000.transformVector(Vector3D.PLUS_K);
    Frame poleAligned = new Frame(FramesFactory.getEME2000(), new Transform(date, new Rotation(pole, Vector3D.PLUS_K)), "pole aligned", true);
    double i = FastMath.toRadians(98.7);
    double omega = FastMath.toRadians(93.0);
    double OMEGA = FastMath.toRadians(15.0 * 22.5);
    Orbit orbit = new KeplerianOrbit(7201009.7124401, 1e-3, i, omega, OMEGA, 0, PositionAngle.MEAN, poleAligned, date, mu);
    double[][] c = new double[3][1];
    c[0][0] = 0.0;
    c[2][0] = normalizedC20;
    double[][] s = new double[3][1];
    propagator.addForceModel(new HolmesFeatherstoneAttractionModel(itrf, GravityFieldFactory.getNormalizedProvider(6378136.460, mu, TideSystem.UNKNOWN, c, s)));
    // let the step handler perform the test
    propagator.setMasterMode(Constants.JULIAN_DAY, new SpotStepHandler(date, mu));
    propagator.setInitialState(new SpacecraftState(orbit));
    propagator.propagate(date.shiftedBy(7 * Constants.JULIAN_DAY));
    Assert.assertTrue(propagator.getCalls() < 9200);
}

Example 9 with KeplerianOrbit

use of org.orekit.orbits.KeplerianOrbit in project Orekit by CS-SI.

the class HolmesFeatherstoneAttractionModelTest method RealFieldTest.

/**
 *Testing if the propagation between the FieldPropagation and the propagation
 * is equivalent.
 * Also testing if propagating X+dX with the propagation is equivalent to
 * propagation X with the FieldPropagation and then applying the taylor
 * expansion of dX to the result.
 */
@Test
public void RealFieldTest() throws OrekitException {
    DSFactory factory = new DSFactory(6, 4);
    DerivativeStructure a_0 = factory.variable(0, 7201009.7124401);
    DerivativeStructure e_0 = factory.variable(1, 1e-3);
    DerivativeStructure i_0 = factory.variable(2, 98.7 * FastMath.PI / 180);
    DerivativeStructure R_0 = factory.variable(3, 15.0 * 22.5 * FastMath.PI / 180);
    DerivativeStructure O_0 = factory.variable(4, 93.0 * FastMath.PI / 180);
    DerivativeStructure n_0 = factory.variable(5, 0.1);
    Field<DerivativeStructure> field = a_0.getField();
    DerivativeStructure zero = field.getZero();
    FieldAbsoluteDate<DerivativeStructure> J2000 = new FieldAbsoluteDate<>(field);
    Frame EME = FramesFactory.getEME2000();
    FieldKeplerianOrbit<DerivativeStructure> FKO = new FieldKeplerianOrbit<>(a_0, e_0, i_0, R_0, O_0, n_0, PositionAngle.MEAN, EME, J2000, Constants.EIGEN5C_EARTH_MU);
    FieldSpacecraftState<DerivativeStructure> initialState = new FieldSpacecraftState<>(FKO);
    SpacecraftState iSR = initialState.toSpacecraftState();
    OrbitType type = OrbitType.EQUINOCTIAL;
    double[][] tolerance = NumericalPropagator.tolerances(10.0, FKO.toOrbit(), type);
    AdaptiveStepsizeFieldIntegrator<DerivativeStructure> integrator = new DormandPrince853FieldIntegrator<>(field, 0.001, 200, tolerance[0], tolerance[1]);
    integrator.setInitialStepSize(zero.add(60));
    AdaptiveStepsizeIntegrator RIntegrator = new DormandPrince853Integrator(0.001, 200, tolerance[0], tolerance[1]);
    RIntegrator.setInitialStepSize(60);
    FieldNumericalPropagator<DerivativeStructure> FNP = new FieldNumericalPropagator<>(field, integrator);
    FNP.setOrbitType(type);
    FNP.setInitialState(initialState);
    NumericalPropagator NP = new NumericalPropagator(RIntegrator);
    NP.setOrbitType(type);
    NP.setInitialState(iSR);
    double[][] c = new double[3][1];
    c[0][0] = 0.0;
    c[2][0] = normalizedC20;
    double[][] s = new double[3][1];
    NormalizedSphericalHarmonicsProvider provider = GravityFieldFactory.getNormalizedProvider(6378136.460, mu, TideSystem.UNKNOWN, c, s);
    HolmesFeatherstoneAttractionModel forceModel = new HolmesFeatherstoneAttractionModel(itrf, provider);
    FNP.addForceModel(forceModel);
    NP.addForceModel(forceModel);
    FieldAbsoluteDate<DerivativeStructure> target = J2000.shiftedBy(1005.);
    FieldSpacecraftState<DerivativeStructure> finalState_DS = FNP.propagate(target);
    SpacecraftState finalState_R = NP.propagate(target.toAbsoluteDate());
    FieldPVCoordinates<DerivativeStructure> finPVC_DS = finalState_DS.getPVCoordinates();
    PVCoordinates finPVC_R = finalState_R.getPVCoordinates();
    Assert.assertEquals(finPVC_DS.toPVCoordinates().getPosition().getX(), finPVC_R.getPosition().getX(), FastMath.abs(finPVC_R.getPosition().getX()) * 1e-11);
    Assert.assertEquals(finPVC_DS.toPVCoordinates().getPosition().getY(), finPVC_R.getPosition().getY(), FastMath.abs(finPVC_R.getPosition().getY()) * 1e-11);
    Assert.assertEquals(finPVC_DS.toPVCoordinates().getPosition().getZ(), finPVC_R.getPosition().getZ(), FastMath.abs(finPVC_R.getPosition().getZ()) * 1e-11);
    long number = 23091991;
    RandomGenerator RG = new Well19937a(number);
    GaussianRandomGenerator NGG = new GaussianRandomGenerator(RG);
    UncorrelatedRandomVectorGenerator URVG = new UncorrelatedRandomVectorGenerator(new double[] { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 }, new double[] { 1e1, 0.001, 0.001, 0.001, 0.001, 0.001 }, NGG);
    double a_R = a_0.getReal();
    double e_R = e_0.getReal();
    double i_R = i_0.getReal();
    double R_R = R_0.getReal();
    double O_R = O_0.getReal();
    double n_R = n_0.getReal();
    for (int ii = 0; ii < 1; ii++) {
        double[] rand_next = URVG.nextVector();
        double a_shift = a_R + rand_next[0];
        double e_shift = e_R + rand_next[1];
        double i_shift = i_R + rand_next[2];
        double R_shift = R_R + rand_next[3];
        double O_shift = O_R + rand_next[4];
        double n_shift = n_R + rand_next[5];
        KeplerianOrbit shiftedOrb = new KeplerianOrbit(a_shift, e_shift, i_shift, R_shift, O_shift, n_shift, PositionAngle.MEAN, EME, J2000.toAbsoluteDate(), Constants.EIGEN5C_EARTH_MU);
        SpacecraftState shift_iSR = new SpacecraftState(shiftedOrb);
        NumericalPropagator shift_NP = new NumericalPropagator(RIntegrator);
        shift_NP.setOrbitType(type);
        shift_NP.setInitialState(shift_iSR);
        shift_NP.addForceModel(forceModel);
        SpacecraftState finalState_shift = shift_NP.propagate(target.toAbsoluteDate());
        PVCoordinates finPVC_shift = finalState_shift.getPVCoordinates();
        // position check
        FieldVector3D<DerivativeStructure> pos_DS = finPVC_DS.getPosition();
        double x_DS = pos_DS.getX().taylor(rand_next[0], rand_next[1], rand_next[2], rand_next[3], rand_next[4], rand_next[5]);
        double y_DS = pos_DS.getY().taylor(rand_next[0], rand_next[1], rand_next[2], rand_next[3], rand_next[4], rand_next[5]);
        double z_DS = pos_DS.getZ().taylor(rand_next[0], rand_next[1], rand_next[2], rand_next[3], rand_next[4], rand_next[5]);
        double x = finPVC_shift.getPosition().getX();
        double y = finPVC_shift.getPosition().getY();
        double z = finPVC_shift.getPosition().getZ();
        Assert.assertEquals(x_DS, x, FastMath.abs(x - pos_DS.getX().getReal()) * 1e-8);
        Assert.assertEquals(y_DS, y, FastMath.abs(y - pos_DS.getY().getReal()) * 1e-8);
        Assert.assertEquals(z_DS, z, FastMath.abs(z - pos_DS.getZ().getReal()) * 1e-8);
        // velocity check
        FieldVector3D<DerivativeStructure> vel_DS = finPVC_DS.getVelocity();
        double vx_DS = vel_DS.getX().taylor(rand_next[0], rand_next[1], rand_next[2], rand_next[3], rand_next[4], rand_next[5]);
        double vy_DS = vel_DS.getY().taylor(rand_next[0], rand_next[1], rand_next[2], rand_next[3], rand_next[4], rand_next[5]);
        double vz_DS = vel_DS.getZ().taylor(rand_next[0], rand_next[1], rand_next[2], rand_next[3], rand_next[4], rand_next[5]);
        double vx = finPVC_shift.getVelocity().getX();
        double vy = finPVC_shift.getVelocity().getY();
        double vz = finPVC_shift.getVelocity().getZ();
        Assert.assertEquals(vx_DS, vx, FastMath.abs(vx) * 1e-9);
        Assert.assertEquals(vy_DS, vy, FastMath.abs(vy) * 1e-9);
        Assert.assertEquals(vz_DS, vz, FastMath.abs(vz) * 1e-9);
        // acceleration check
        FieldVector3D<DerivativeStructure> acc_DS = finPVC_DS.getAcceleration();
        double ax_DS = acc_DS.getX().taylor(rand_next[0], rand_next[1], rand_next[2], rand_next[3], rand_next[4], rand_next[5]);
        double ay_DS = acc_DS.getY().taylor(rand_next[0], rand_next[1], rand_next[2], rand_next[3], rand_next[4], rand_next[5]);
        double az_DS = acc_DS.getZ().taylor(rand_next[0], rand_next[1], rand_next[2], rand_next[3], rand_next[4], rand_next[5]);
        double ax = finPVC_shift.getAcceleration().getX();
        double ay = finPVC_shift.getAcceleration().getY();
        double az = finPVC_shift.getAcceleration().getZ();
        Assert.assertEquals(ax_DS, ax, FastMath.abs(ax) * 1e-9);
        Assert.assertEquals(ay_DS, ay, FastMath.abs(ay) * 1e-9);
        Assert.assertEquals(az_DS, az, FastMath.abs(az) * 1e-9);
    }
}

Example 10 with KeplerianOrbit

use of org.orekit.orbits.KeplerianOrbit in project Orekit by CS-SI.

the class HolmesFeatherstoneAttractionModelTest method testStateJacobian.

@Test
public void testStateJacobian() throws OrekitException {
    Utils.setDataRoot("regular-data:potential/grgs-format");
    GravityFieldFactory.addPotentialCoefficientsReader(new GRGSFormatReader("grim4s4_gr", true));
    // initialization
    AbsoluteDate date = new AbsoluteDate(new DateComponents(2000, 07, 01), new TimeComponents(13, 59, 27.816), TimeScalesFactory.getUTC());
    double i = FastMath.toRadians(98.7);
    double omega = FastMath.toRadians(93.0);
    double OMEGA = FastMath.toRadians(15.0 * 22.5);
    Orbit orbit = new KeplerianOrbit(7201009.7124401, 1e-3, i, omega, OMEGA, 0, PositionAngle.MEAN, FramesFactory.getEME2000(), date, mu);
    OrbitType integrationType = OrbitType.CARTESIAN;
    double[][] tolerances = NumericalPropagator.tolerances(0.01, orbit, integrationType);
    propagator = new NumericalPropagator(new DormandPrince853Integrator(1.0e-3, 120, tolerances[0], tolerances[1]));
    propagator.setOrbitType(integrationType);
    HolmesFeatherstoneAttractionModel hfModel = new HolmesFeatherstoneAttractionModel(itrf, GravityFieldFactory.getNormalizedProvider(50, 50));
    Assert.assertEquals(TideSystem.UNKNOWN, hfModel.getTideSystem());
    propagator.addForceModel(hfModel);
    SpacecraftState state0 = new SpacecraftState(orbit);
    propagator.setInitialState(state0);
    checkStateJacobian(propagator, state0, date.shiftedBy(3.5 * 3600.0), 50000, tolerances[0], 7.8e-6);
}