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

Example 1 with Orbit

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

the class HarmonicParametricAccelerationTest method testCoefficientsDetermination.

@Test
public void testCoefficientsDetermination() throws OrekitException {
    final double mass = 2500;
    final Orbit orbit = new CircularOrbit(7500000.0, 1.0e-4, 1.0e-3, 1.7, 0.3, 0.5, PositionAngle.TRUE, FramesFactory.getEME2000(), new AbsoluteDate(new DateComponents(2004, 2, 3), TimeComponents.H00, TimeScalesFactory.getUTC()), Constants.EIGEN5C_EARTH_MU);
    final double period = orbit.getKeplerianPeriod();
    AttitudeProvider maneuverLaw = new LofOffset(orbit.getFrame(), LOFType.VNC);
    SpacecraftState initialState = new SpacecraftState(orbit, maneuverLaw.getAttitude(orbit, orbit.getDate(), orbit.getFrame()), mass);
    double dP = 10.0;
    double minStep = 0.001;
    double maxStep = 100;
    double[][] tolerance = NumericalPropagator.tolerances(dP, orbit, orbit.getType());
    // generate PV measurements corresponding to a tangential maneuver
    AdaptiveStepsizeIntegrator integrator0 = new DormandPrince853Integrator(minStep, maxStep, tolerance[0], tolerance[1]);
    integrator0.setInitialStepSize(60);
    final NumericalPropagator propagator0 = new NumericalPropagator(integrator0);
    propagator0.setInitialState(initialState);
    propagator0.setAttitudeProvider(maneuverLaw);
    ForceModel hpaRefX1 = new HarmonicParametricAcceleration(Vector3D.PLUS_I, true, "refX1", null, period, 1);
    ForceModel hpaRefY1 = new HarmonicParametricAcceleration(Vector3D.PLUS_J, true, "refY1", null, period, 1);
    ForceModel hpaRefZ2 = new HarmonicParametricAcceleration(Vector3D.PLUS_K, true, "refZ2", null, period, 2);
    hpaRefX1.getParametersDrivers()[0].setValue(2.4e-2);
    hpaRefX1.getParametersDrivers()[1].setValue(3.1);
    hpaRefY1.getParametersDrivers()[0].setValue(4.0e-2);
    hpaRefY1.getParametersDrivers()[1].setValue(0.3);
    hpaRefZ2.getParametersDrivers()[0].setValue(1.0e-2);
    hpaRefZ2.getParametersDrivers()[1].setValue(1.8);
    propagator0.addForceModel(hpaRefX1);
    propagator0.addForceModel(hpaRefY1);
    propagator0.addForceModel(hpaRefZ2);
    final List<ObservedMeasurement<?>> measurements = new ArrayList<>();
    propagator0.setMasterMode(10.0, (state, isLast) -> measurements.add(new PV(state.getDate(), state.getPVCoordinates().getPosition(), state.getPVCoordinates().getVelocity(), 1.0e-3, 1.0e-6, 1.0)));
    propagator0.propagate(orbit.getDate().shiftedBy(900));
    // set up an estimator to retrieve the maneuver as several harmonic accelerations in inertial frame
    final NumericalPropagatorBuilder propagatorBuilder = new NumericalPropagatorBuilder(orbit, new DormandPrince853IntegratorBuilder(minStep, maxStep, dP), PositionAngle.TRUE, dP);
    propagatorBuilder.addForceModel(new HarmonicParametricAcceleration(Vector3D.PLUS_I, true, "X1", null, period, 1));
    propagatorBuilder.addForceModel(new HarmonicParametricAcceleration(Vector3D.PLUS_J, true, "Y1", null, period, 1));
    propagatorBuilder.addForceModel(new HarmonicParametricAcceleration(Vector3D.PLUS_K, true, "Z2", null, period, 2));
    final BatchLSEstimator estimator = new BatchLSEstimator(new LevenbergMarquardtOptimizer(), propagatorBuilder);
    estimator.setParametersConvergenceThreshold(1.0e-2);
    estimator.setMaxIterations(20);
    estimator.setMaxEvaluations(100);
    for (final ObservedMeasurement<?> measurement : measurements) {
        estimator.addMeasurement(measurement);
    }
    // we will estimate only the force model parameters, not the orbit
    for (final ParameterDriver d : estimator.getOrbitalParametersDrivers(false).getDrivers()) {
        d.setSelected(false);
    }
    setParameter(estimator, "X1 γ", 1.0e-2);
    setParameter(estimator, "X1 φ", 4.0);
    setParameter(estimator, "Y1 γ", 1.0e-2);
    setParameter(estimator, "Y1 φ", 0.0);
    setParameter(estimator, "Z2 γ", 1.0e-2);
    setParameter(estimator, "Z2 φ", 1.0);
    estimator.estimate();
    Assert.assertTrue(estimator.getIterationsCount() < 15);
    Assert.assertTrue(estimator.getEvaluationsCount() < 15);
    Assert.assertEquals(0.0, estimator.getOptimum().getRMS(), 1.0e-5);
    Assert.assertEquals(hpaRefX1.getParametersDrivers()[0].getValue(), getParameter(estimator, "X1 γ"), 1.e-12);
    Assert.assertEquals(hpaRefX1.getParametersDrivers()[1].getValue(), getParameter(estimator, "X1 φ"), 1.e-12);
    Assert.assertEquals(hpaRefY1.getParametersDrivers()[0].getValue(), getParameter(estimator, "Y1 γ"), 1.e-12);
    Assert.assertEquals(hpaRefY1.getParametersDrivers()[1].getValue(), getParameter(estimator, "Y1 φ"), 1.e-12);
    Assert.assertEquals(hpaRefZ2.getParametersDrivers()[0].getValue(), getParameter(estimator, "Z2 γ"), 1.e-12);
    Assert.assertEquals(hpaRefZ2.getParametersDrivers()[1].getValue(), getParameter(estimator, "Z2 φ"), 1.e-12);
}

Example 2 with Orbit

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

the class DragForceTest method testStateJacobianSphere.

@Test
public void testStateJacobianSphere() throws OrekitException {
    // initialization
    AbsoluteDate date = new AbsoluteDate(new DateComponents(2003, 03, 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, Constants.EIGEN5C_EARTH_MU);
    OrbitType integrationType = OrbitType.CARTESIAN;
    double[][] tolerances = NumericalPropagator.tolerances(0.01, orbit, integrationType);
    NumericalPropagator propagator = new NumericalPropagator(new DormandPrince853Integrator(1.0e-3, 120, tolerances[0], tolerances[1]));
    propagator.setOrbitType(integrationType);
    final DragForce forceModel = new DragForce(new HarrisPriester(CelestialBodyFactory.getSun(), new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, FramesFactory.getITRF(IERSConventions.IERS_2010, true))), new IsotropicDrag(2.5, 1.2));
    propagator.addForceModel(forceModel);
    SpacecraftState state0 = new SpacecraftState(orbit);
    checkStateJacobian(propagator, state0, date.shiftedBy(3.5 * 3600.0), 1e3, tolerances[0], 2.0e-8);
}

Example 3 with Orbit

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

the class DragForceTest method testJacobianBoxVsFiniteDifferences.

@Test
public void testJacobianBoxVsFiniteDifferences() throws OrekitException {
    // initialization
    AbsoluteDate date = new AbsoluteDate(new DateComponents(2003, 03, 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, Constants.EIGEN5C_EARTH_MU);
    final DragForce forceModel = new DragForce(new HarrisPriester(CelestialBodyFactory.getSun(), new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, FramesFactory.getITRF(IERSConventions.IERS_2010, true))), new BoxAndSolarArraySpacecraft(1.5, 2.0, 1.8, CelestialBodyFactory.getSun(), 20.0, Vector3D.PLUS_J, 1.2, 0.7, 0.2));
    SpacecraftState state = new SpacecraftState(orbit, Propagator.DEFAULT_LAW.getAttitude(orbit, orbit.getDate(), orbit.getFrame()));
    checkStateJacobianVsFiniteDifferences(state, forceModel, Propagator.DEFAULT_LAW, 1.0, 5.0e-6, false);
}

Example 4 with Orbit

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

the class DragForceTest method testGlobalStateJacobianBox.

@Test
public void testGlobalStateJacobianBox() throws OrekitException {
    // initialization
    AbsoluteDate date = new AbsoluteDate(new DateComponents(2003, 03, 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, Constants.EIGEN5C_EARTH_MU);
    OrbitType integrationType = OrbitType.CARTESIAN;
    double[][] tolerances = NumericalPropagator.tolerances(0.01, orbit, integrationType);
    NumericalPropagator propagator = new NumericalPropagator(new DormandPrince853Integrator(1.0e-3, 120, tolerances[0], tolerances[1]));
    propagator.setOrbitType(integrationType);
    final DragForce forceModel = new DragForce(new HarrisPriester(CelestialBodyFactory.getSun(), new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, FramesFactory.getITRF(IERSConventions.IERS_2010, true))), new BoxAndSolarArraySpacecraft(1.5, 2.0, 1.8, CelestialBodyFactory.getSun(), 20.0, Vector3D.PLUS_J, 1.2, 0.7, 0.2));
    propagator.addForceModel(forceModel);
    SpacecraftState state0 = new SpacecraftState(orbit);
    checkStateJacobian(propagator, state0, date.shiftedBy(3.5 * 3600.0), 1e3, tolerances[0], 3.0e-8);
}

Example 5 with Orbit

use of org.orekit.orbits.Orbit 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));
}