Examples with NumericalPropagator org.orekit.propagation.numerical.NumericalPropagator used on opensource projects

Example 36 with NumericalPropagator

use of org.orekit.propagation.numerical.NumericalPropagator in project Orekit by CS-SI.

the class SolarRadiationPressureTest 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);
    SolarRadiationPressure forceModel = new SolarRadiationPressure(CelestialBodyFactory.getSun(), Constants.WGS84_EARTH_EQUATORIAL_RADIUS, 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], 5.0e-4);
}

Example 37 with NumericalPropagator

use of org.orekit.propagation.numerical.NumericalPropagator in project Orekit by CS-SI.

the class Model method value.

/**
 * {@inheritDoc}
 */
@Override
public Pair<RealVector, RealMatrix> value(final RealVector point) throws OrekitExceptionWrapper {
    try {
        // Set up the propagators parallelizer
        final NumericalPropagator[] propagators = createPropagators(point);
        final Orbit[] orbits = new Orbit[propagators.length];
        for (int i = 0; i < propagators.length; ++i) {
            mappers[i] = configureDerivatives(propagators[i]);
            orbits[i] = propagators[i].getInitialState().getOrbit();
        }
        final PropagatorsParallelizer parallelizer = new PropagatorsParallelizer(Arrays.asList(propagators), configureMeasurements(point));
        // Reset value and Jacobian
        evaluations.clear();
        value.set(0.0);
        for (int i = 0; i < jacobian.getRowDimension(); ++i) {
            for (int j = 0; j < jacobian.getColumnDimension(); ++j) {
                jacobian.setEntry(i, j, 0.0);
            }
        }
        // Run the propagation, gathering residuals on the fly
        if (forwardPropagation) {
            // Propagate forward from firstDate
            parallelizer.propagate(firstDate.shiftedBy(-1.0), lastDate.shiftedBy(+1.0));
        } else {
            // Propagate backward from lastDate
            parallelizer.propagate(lastDate.shiftedBy(+1.0), firstDate.shiftedBy(-1.0));
        }
        observer.modelCalled(orbits, evaluations);
        return new Pair<RealVector, RealMatrix>(value, jacobian);
    } catch (OrekitException oe) {
        throw new OrekitExceptionWrapper(oe);
    }
}

Example 38 with NumericalPropagator

use of org.orekit.propagation.numerical.NumericalPropagator in project Orekit by CS-SI.

the class Model method createPropagators.

/**
 * Create the propagators and parameters corresponding to an evaluation point.
 * @param point evaluation point
 * @return an array of new propagators
 * @exception OrekitException if orbit cannot be created with the current point
 */
public NumericalPropagator[] createPropagators(final RealVector point) throws OrekitException {
    final NumericalPropagator[] propagators = new NumericalPropagator[builders.length];
    // Set up the propagators
    for (int i = 0; i < builders.length; ++i) {
        // Get the number of selected orbital drivers in the builder
        final int nbOrb = orbitsEndColumns[i] - orbitsStartColumns[i];
        // Get the list of selected propagation drivers in the builder and its size
        final ParameterDriversList selectedPropagationDrivers = getSelectedPropagationDriversForBuilder(i);
        final int nbParams = selectedPropagationDrivers.getNbParams();
        // Init the array of normalized parameters for the builder
        final double[] propagatorArray = new double[nbOrb + nbParams];
        // Add the orbital drivers normalized values
        for (int j = 0; j < nbOrb; ++j) {
            propagatorArray[j] = point.getEntry(orbitsStartColumns[i] + j);
        }
        // Add the propagation drivers normalized values
        for (int j = 0; j < nbParams; ++j) {
            propagatorArray[nbOrb + j] = point.getEntry(propagationParameterColumns.get(selectedPropagationDrivers.getDrivers().get(j).getName()));
        }
        // Build the propagator
        propagators[i] = builders[i].buildPropagator(propagatorArray);
    }
    return propagators;
}

Example 39 with NumericalPropagator

use of org.orekit.propagation.numerical.NumericalPropagator in project Orekit by CS-SI.

the class PropagatorsParallelizerTest method buildNotInitializedNumerical.

private NumericalPropagator buildNotInitializedNumerical() throws OrekitException {
    OrbitType type = OrbitType.CARTESIAN;
    double minStep = 0.001;
    double maxStep = 300;
    double[][] tolerances = NumericalPropagator.tolerances(10.0, orbit, type);
    ODEIntegrator integrator = new DormandPrince853Integrator(minStep, maxStep, tolerances[0], tolerances[1]);
    NumericalPropagator numericalPropagator = new NumericalPropagator(integrator);
    ForceModel gravity = new HolmesFeatherstoneAttractionModel(FramesFactory.getITRF(IERSConventions.IERS_2010, true), normalizedGravityField);
    numericalPropagator.addForceModel(gravity);
    return numericalPropagator;
}

Example 40 with NumericalPropagator

use of org.orekit.propagation.numerical.NumericalPropagator in project Orekit by CS-SI.

the class EcksteinHechlerPropagatorTest method testInitializationCorrectness.

@Test
public void testInitializationCorrectness() throws OrekitException, IOException {
    // Definition of initial conditions
    AbsoluteDate date = AbsoluteDate.J2000_EPOCH.shiftedBy(154.);
    Frame itrf = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
    Frame eme2000 = FramesFactory.getEME2000();
    Vector3D pole = itrf.getTransformTo(eme2000, date).transformVector(Vector3D.PLUS_K);
    Frame poleAligned = new Frame(FramesFactory.getEME2000(), new Transform(date, new Rotation(pole, Vector3D.PLUS_K)), "pole aligned", true);
    CircularOrbit initial = new CircularOrbit(7208669.8179538045, 1.3740461966386876E-4, -3.2364250248363356E-5, FastMath.toRadians(97.40236024565775), FastMath.toRadians(166.15873160992115), FastMath.toRadians(90.1282370098961), PositionAngle.MEAN, poleAligned, date, provider.getMu());
    // find the default Eckstein-Hechler propagator initialized from the initial orbit
    EcksteinHechlerPropagator defaultEH = new EcksteinHechlerPropagator(initial, provider);
    // the osculating parameters recomputed by the default Eckstein-Hechler propagator are quite different
    // from initial orbit
    CircularOrbit defaultOrbit = (CircularOrbit) OrbitType.CIRCULAR.convertType(defaultEH.propagateOrbit(initial.getDate()));
    Assert.assertEquals(267.4, defaultOrbit.getA() - initial.getA(), 0.1);
    // the position on the other hand match perfectly
    Assert.assertEquals(0.0, Vector3D.distance(defaultOrbit.getPVCoordinates().getPosition(), initial.getPVCoordinates().getPosition()), 1.0e-8);
    // set up a reference numerical propagator starting for the specified start orbit
    // using the same force models (i.e. the first few zonal terms)
    double[][] tol = NumericalPropagator.tolerances(0.1, initial, OrbitType.CIRCULAR);
    AdaptiveStepsizeIntegrator integrator = new DormandPrince853Integrator(0.001, 1000, tol[0], tol[1]);
    integrator.setInitialStepSize(60);
    NumericalPropagator num = new NumericalPropagator(integrator);
    num.addForceModel(new HolmesFeatherstoneAttractionModel(itrf, GravityFieldFactory.getNormalizedProvider(provider)));
    num.setInitialState(new SpacecraftState(initial));
    num.setOrbitType(OrbitType.CIRCULAR);
    // find the best Eckstein-Hechler propagator that match the orbit evolution
    PropagatorConverter converter = new FiniteDifferencePropagatorConverter(new EcksteinHechlerPropagatorBuilder(initial, provider, PositionAngle.TRUE, 1.0), 1.0e-6, 100);
    EcksteinHechlerPropagator fittedEH = (EcksteinHechlerPropagator) converter.convert(num, 3 * initial.getKeplerianPeriod(), 300);
    // the default Eckstein-Hechler propagator did however quite a good job, as it found
    // an orbit close to the best fitting
    CircularOrbit fittedOrbit = (CircularOrbit) OrbitType.CIRCULAR.convertType(fittedEH.propagateOrbit(initial.getDate()));
    Assert.assertEquals(0.623, defaultOrbit.getA() - fittedOrbit.getA(), 0.1);
    // the position on the other hand are slightly different
    // because the fitted orbit minimizes the residuals over a complete time span,
    // not on a single point
    Assert.assertEquals(58.0, Vector3D.distance(defaultOrbit.getPVCoordinates().getPosition(), fittedOrbit.getPVCoordinates().getPosition()), 0.1);
}