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

Example 86 with NumericalPropagator

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

the class PropagatorsParallelizerTest method buildNumerical.

private NumericalPropagator buildNumerical() throws OrekitException {
    NumericalPropagator numericalPropagator = buildNotInitializedNumerical();
    numericalPropagator.setInitialState(new SpacecraftState(orbit, attitudeLaw.getAttitude(orbit, orbit.getDate(), orbit.getFrame()), mass));
    return numericalPropagator;
}

Example 87 with NumericalPropagator

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

the class AdapterPropagatorTest method getEphemeris.

private BoundedPropagator getEphemeris(final Orbit orbit, final double mass, final int nbOrbits, final AttitudeProvider law, final AbsoluteDate t0, final Vector3D dV, final double f, final double isp, final boolean sunAttraction, final boolean moonAttraction, final NormalizedSphericalHarmonicsProvider gravityField) throws OrekitException, ParseException, IOException {
    SpacecraftState initialState = new SpacecraftState(orbit, law.getAttitude(orbit, orbit.getDate(), orbit.getFrame()), mass);
    // add some dummy additional states
    initialState = initialState.addAdditionalState("dummy 1", 1.25, 2.5);
    initialState = initialState.addAdditionalState("dummy 2", 5.0);
    // set up numerical propagator
    final double dP = 1.0;
    double[][] tolerances = NumericalPropagator.tolerances(dP, orbit, orbit.getType());
    AdaptiveStepsizeIntegrator integrator = new DormandPrince853Integrator(0.001, 1000, tolerances[0], tolerances[1]);
    integrator.setInitialStepSize(orbit.getKeplerianPeriod() / 100.0);
    final NumericalPropagator propagator = new NumericalPropagator(integrator);
    propagator.addAdditionalStateProvider(new AdditionalStateProvider() {

        public String getName() {
            return "dummy 2";
        }

        public double[] getAdditionalState(SpacecraftState state) {
            return new double[] { 5.0 };
        }
    });
    propagator.setInitialState(initialState);
    propagator.setAttitudeProvider(law);
    if (dV.getNorm() > 1.0e-6) {
        // set up maneuver
        final double vExhaust = Constants.G0_STANDARD_GRAVITY * isp;
        final double dt = -(mass * vExhaust / f) * FastMath.expm1(-dV.getNorm() / vExhaust);
        final ConstantThrustManeuver maneuver = new ConstantThrustManeuver(t0.shiftedBy(-0.5 * dt), dt, f, isp, dV.normalize());
        propagator.addForceModel(maneuver);
    }
    if (sunAttraction) {
        propagator.addForceModel(new ThirdBodyAttraction(CelestialBodyFactory.getSun()));
    }
    if (moonAttraction) {
        propagator.addForceModel(new ThirdBodyAttraction(CelestialBodyFactory.getMoon()));
    }
    if (gravityField != null) {
        propagator.addForceModel(new HolmesFeatherstoneAttractionModel(FramesFactory.getGTOD(false), gravityField));
    }
    propagator.setEphemerisMode();
    propagator.propagate(t0.shiftedBy(nbOrbits * orbit.getKeplerianPeriod()));
    final BoundedPropagator ephemeris = propagator.getGeneratedEphemeris();
    // both the initial propagator and generated ephemeris manage one of the two
    // additional states, but they also contain unmanaged copies of the other one
    Assert.assertFalse(propagator.isAdditionalStateManaged("dummy 1"));
    Assert.assertTrue(propagator.isAdditionalStateManaged("dummy 2"));
    Assert.assertFalse(ephemeris.isAdditionalStateManaged("dummy 1"));
    Assert.assertTrue(ephemeris.isAdditionalStateManaged("dummy 2"));
    Assert.assertEquals(2, ephemeris.getInitialState().getAdditionalState("dummy 1").length);
    Assert.assertEquals(1, ephemeris.getInitialState().getAdditionalState("dummy 2").length);
    return ephemeris;
}

Example 88 with NumericalPropagator

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

the class Phasing method run.

private void run(final File input) throws IOException, IllegalArgumentException, ParseException, OrekitException {
    // read input parameters
    KeyValueFileParser<ParameterKey> parser = new KeyValueFileParser<ParameterKey>(ParameterKey.class);
    try (final FileInputStream fis = new FileInputStream(input)) {
        parser.parseInput(input.getAbsolutePath(), fis);
    }
    TimeScale utc = TimeScalesFactory.getUTC();
    // simulation properties
    AbsoluteDate date = parser.getDate(ParameterKey.ORBIT_DATE, utc);
    int nbOrbits = parser.getInt(ParameterKey.PHASING_ORBITS_NUMBER);
    int nbDays = parser.getInt(ParameterKey.PHASING_DAYS_NUMBER);
    double latitude = parser.getAngle(ParameterKey.SUN_SYNCHRONOUS_REFERENCE_LATITUDE);
    boolean ascending = parser.getBoolean(ParameterKey.SUN_SYNCHRONOUS_REFERENCE_ASCENDING);
    double mst = parser.getTime(ParameterKey.SUN_SYNCHRONOUS_MEAN_SOLAR_TIME).getSecondsInUTCDay() / 3600;
    int degree = parser.getInt(ParameterKey.GRAVITY_FIELD_DEGREE);
    int order = parser.getInt(ParameterKey.GRAVITY_FIELD_ORDER);
    String gridOutput = parser.getString(ParameterKey.GRID_OUTPUT);
    double[] gridLatitudes = new double[] { parser.getAngle(ParameterKey.GRID_LATITUDE_1), parser.getAngle(ParameterKey.GRID_LATITUDE_2), parser.getAngle(ParameterKey.GRID_LATITUDE_3), parser.getAngle(ParameterKey.GRID_LATITUDE_4), parser.getAngle(ParameterKey.GRID_LATITUDE_5) };
    boolean[] gridAscending = new boolean[] { parser.getBoolean(ParameterKey.GRID_ASCENDING_1), parser.getBoolean(ParameterKey.GRID_ASCENDING_2), parser.getBoolean(ParameterKey.GRID_ASCENDING_3), parser.getBoolean(ParameterKey.GRID_ASCENDING_4), parser.getBoolean(ParameterKey.GRID_ASCENDING_5) };
    gravityField = GravityFieldFactory.getNormalizedProvider(degree, order);
    // initial guess for orbit
    CircularOrbit orbit = guessOrbit(date, FramesFactory.getEME2000(), nbOrbits, nbDays, latitude, ascending, mst);
    System.out.println("initial orbit: " + orbit);
    System.out.println("please wait while orbit is adjusted...");
    System.out.println();
    // numerical model for improving orbit
    double[][] tolerances = NumericalPropagator.tolerances(0.1, orbit, OrbitType.CIRCULAR);
    DormandPrince853Integrator integrator = new DormandPrince853Integrator(1.0e-4 * orbit.getKeplerianPeriod(), 1.0e-1 * orbit.getKeplerianPeriod(), tolerances[0], tolerances[1]);
    integrator.setInitialStepSize(1.0e-2 * orbit.getKeplerianPeriod());
    NumericalPropagator propagator = new NumericalPropagator(integrator);
    propagator.addForceModel(new HolmesFeatherstoneAttractionModel(FramesFactory.getGTOD(IERSConventions.IERS_2010, true), gravityField));
    propagator.addForceModel(new ThirdBodyAttraction(CelestialBodyFactory.getSun()));
    propagator.addForceModel(new ThirdBodyAttraction(CelestialBodyFactory.getMoon()));
    double deltaP = Double.POSITIVE_INFINITY;
    double deltaV = Double.POSITIVE_INFINITY;
    int counter = 0;
    DecimalFormat f = new DecimalFormat("0.000E00", new DecimalFormatSymbols(Locale.US));
    while (deltaP > 3.0e-1 || deltaV > 3.0e-4) {
        CircularOrbit previous = orbit;
        CircularOrbit tmp1 = improveEarthPhasing(previous, nbOrbits, nbDays, propagator);
        CircularOrbit tmp2 = improveSunSynchronization(tmp1, nbOrbits * tmp1.getKeplerianPeriod(), latitude, ascending, mst, propagator);
        orbit = improveFrozenEccentricity(tmp2, nbOrbits * tmp2.getKeplerianPeriod(), propagator);
        double da = orbit.getA() - previous.getA();
        double dex = orbit.getCircularEx() - previous.getCircularEx();
        double dey = orbit.getCircularEy() - previous.getCircularEy();
        double di = FastMath.toDegrees(orbit.getI() - previous.getI());
        double dr = FastMath.toDegrees(orbit.getRightAscensionOfAscendingNode() - previous.getRightAscensionOfAscendingNode());
        System.out.println(" iteration " + (++counter) + ": deltaA = " + f.format(da) + " m, deltaEx = " + f.format(dex) + ", deltaEy = " + f.format(dey) + ", deltaI = " + f.format(di) + " deg, deltaRAAN = " + f.format(dr) + " deg");
        PVCoordinates delta = new PVCoordinates(previous.getPVCoordinates(), orbit.getPVCoordinates());
        deltaP = delta.getPosition().getNorm();
        deltaV = delta.getVelocity().getNorm();
    }
    // final orbit
    System.out.println();
    System.out.println("final orbit (osculating): " + orbit);
    // generate the ground track grid file
    try (PrintStream output = new PrintStream(new File(input.getParent(), gridOutput), "UTF-8")) {
        for (int i = 0; i < gridLatitudes.length; ++i) {
            printGridPoints(output, gridLatitudes[i], gridAscending[i], orbit, propagator, nbOrbits);
        }
    }
}

Example 89 with NumericalPropagator

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

the class PropagatorConversion method main.

/**
 * Program entry point.
 * @param args program arguments (unused here)
 */
public static void main(String[] args) {
    try {
        // configure Orekit
        File home = new File(System.getProperty("user.home"));
        File orekitData = new File(home, "orekit-data");
        if (!orekitData.exists()) {
            System.err.format(Locale.US, "Failed to find %s folder%n", orekitData.getAbsolutePath());
            System.err.format(Locale.US, "You need to download %s from the %s page and unzip it in %s for this tutorial to work%n", "orekit-data.zip", "https://www.orekit.org/forge/projects/orekit/files", home.getAbsolutePath());
            System.exit(1);
        }
        DataProvidersManager manager = DataProvidersManager.getInstance();
        manager.addProvider(new DirectoryCrawler(orekitData));
        // gravity field
        NormalizedSphericalHarmonicsProvider provider = GravityFieldFactory.getNormalizedProvider(2, 0);
        double mu = provider.getMu();
        // inertial frame
        Frame inertialFrame = FramesFactory.getEME2000();
        // Initial date
        AbsoluteDate initialDate = new AbsoluteDate(2004, 01, 01, 23, 30, 00.000, TimeScalesFactory.getUTC());
        // Initial orbit (GTO)
        // semi major axis in meters
        final double a = 24396159;
        // eccentricity
        final double e = 0.72831215;
        // inclination
        final double i = FastMath.toRadians(7);
        // perigee argument
        final double omega = FastMath.toRadians(180);
        // right ascention of ascending node
        final double raan = FastMath.toRadians(261);
        // mean anomaly
        final double lM = 0;
        Orbit initialOrbit = new KeplerianOrbit(a, e, i, omega, raan, lM, PositionAngle.MEAN, inertialFrame, initialDate, mu);
        final double period = initialOrbit.getKeplerianPeriod();
        // Initial state definition
        final SpacecraftState initialState = new SpacecraftState(initialOrbit);
        // Adaptive step integrator with a minimum step of 0.001 and a maximum step of 1000
        final double minStep = 0.001;
        final double maxStep = 1000.;
        final double dP = 1.e-2;
        final OrbitType orbType = OrbitType.CARTESIAN;
        final double[][] tol = NumericalPropagator.tolerances(dP, initialOrbit, orbType);
        final AbstractIntegrator integrator = new DormandPrince853Integrator(minStep, maxStep, tol[0], tol[1]);
        // Propagator
        NumericalPropagator numProp = new NumericalPropagator(integrator);
        numProp.setInitialState(initialState);
        numProp.setOrbitType(orbType);
        // Force Models:
        // 1 - Perturbing gravity field (only J2 is considered here)
        ForceModel gravity = new HolmesFeatherstoneAttractionModel(FramesFactory.getITRF(IERSConventions.IERS_2010, true), provider);
        // Add force models to the propagator
        numProp.addForceModel(gravity);
        // Propagator factory
        PropagatorBuilder builder = new KeplerianPropagatorBuilder(initialOrbit, PositionAngle.TRUE, dP);
        // Propagator converter
        PropagatorConverter fitter = new FiniteDifferencePropagatorConverter(builder, 1.e-6, 5000);
        // Resulting propagator
        KeplerianPropagator kepProp = (KeplerianPropagator) fitter.convert(numProp, 2 * period, 251);
        // Step handlers
        StatesHandler numStepHandler = new StatesHandler();
        StatesHandler kepStepHandler = new StatesHandler();
        // Set up operating mode for the propagator as master mode
        // with fixed step and specialized step handler
        numProp.setMasterMode(60., numStepHandler);
        kepProp.setMasterMode(60., kepStepHandler);
        // Extrapolate from the initial to the final date
        numProp.propagate(initialDate.shiftedBy(10. * period));
        kepProp.propagate(initialDate.shiftedBy(10. * period));
        // retrieve the states
        List<SpacecraftState> numStates = numStepHandler.getStates();
        List<SpacecraftState> kepStates = kepStepHandler.getStates();
        // Print the results on the output file
        File output = new File(new File(System.getProperty("user.home")), "elements.dat");
        try (final PrintStream stream = new PrintStream(output, "UTF-8")) {
            stream.println("# date Anum Akep Enum Ekep Inum Ikep LMnum LMkep");
            for (SpacecraftState numState : numStates) {
                for (SpacecraftState kepState : kepStates) {
                    if (numState.getDate().compareTo(kepState.getDate()) == 0) {
                        stream.println(numState.getDate() + " " + numState.getA() + " " + kepState.getA() + " " + numState.getE() + " " + kepState.getE() + " " + FastMath.toDegrees(numState.getI()) + " " + FastMath.toDegrees(kepState.getI()) + " " + FastMath.toDegrees(MathUtils.normalizeAngle(numState.getLM(), FastMath.PI)) + " " + FastMath.toDegrees(MathUtils.normalizeAngle(kepState.getLM(), FastMath.PI)));
                        break;
                    }
                }
            }
        }
        System.out.println("Results saved as file " + output);
        File output1 = new File(new File(System.getProperty("user.home")), "elts_pv.dat");
        try (final PrintStream stream = new PrintStream(output1, "UTF-8")) {
            stream.println("# date pxn pyn pzn vxn vyn vzn pxk pyk pzk vxk vyk vzk");
            for (SpacecraftState numState : numStates) {
                for (SpacecraftState kepState : kepStates) {
                    if (numState.getDate().compareTo(kepState.getDate()) == 0) {
                        final double pxn = numState.getPVCoordinates().getPosition().getX();
                        final double pyn = numState.getPVCoordinates().getPosition().getY();
                        final double pzn = numState.getPVCoordinates().getPosition().getZ();
                        final double vxn = numState.getPVCoordinates().getVelocity().getX();
                        final double vyn = numState.getPVCoordinates().getVelocity().getY();
                        final double vzn = numState.getPVCoordinates().getVelocity().getZ();
                        final double pxk = kepState.getPVCoordinates().getPosition().getX();
                        final double pyk = kepState.getPVCoordinates().getPosition().getY();
                        final double pzk = kepState.getPVCoordinates().getPosition().getZ();
                        final double vxk = kepState.getPVCoordinates().getVelocity().getX();
                        final double vyk = kepState.getPVCoordinates().getVelocity().getY();
                        final double vzk = kepState.getPVCoordinates().getVelocity().getZ();
                        stream.println(numState.getDate() + " " + pxn + " " + pyn + " " + pzn + " " + vxn + " " + vyn + " " + vzn + " " + pxk + " " + pyk + " " + pzk + " " + vxk + " " + vyk + " " + vzk);
                        break;
                    }
                }
            }
        }
        System.out.println("Results saved as file " + output1);
    } catch (OrekitException oe) {
        System.err.println(oe.getLocalizedMessage());
        System.exit(1);
    } catch (IOException ioe) {
        System.err.println(ioe.getLocalizedMessage());
        System.exit(1);
    }
}

Example 90 with NumericalPropagator

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

the class DSSTPropagation method run.

private void run(final File input, final File output) throws IOException, IllegalArgumentException, OrekitException, ParseException {
    // read input parameters
    KeyValueFileParser<ParameterKey> parser = new KeyValueFileParser<ParameterKey>(ParameterKey.class);
    try (final FileInputStream fis = new FileInputStream(input)) {
        parser.parseInput(input.getAbsolutePath(), fis);
    }
    // check mandatory input parameters
    if (!parser.containsKey(ParameterKey.ORBIT_DATE)) {
        throw new IOException("Orbit date is not defined.");
    }
    if (!parser.containsKey(ParameterKey.DURATION) && !parser.containsKey(ParameterKey.DURATION_IN_DAYS)) {
        throw new IOException("Propagation duration is not defined.");
    }
    // All dates in UTC
    final TimeScale utc = TimeScalesFactory.getUTC();
    final double rotationRate;
    if (!parser.containsKey(ParameterKey.CENTRAL_BODY_ROTATION_RATE)) {
        rotationRate = Constants.WGS84_EARTH_ANGULAR_VELOCITY;
    } else {
        rotationRate = parser.getDouble(ParameterKey.CENTRAL_BODY_ROTATION_RATE);
    }
    final int degree = parser.getInt(ParameterKey.CENTRAL_BODY_DEGREE);
    final int order = FastMath.min(degree, parser.getInt(ParameterKey.CENTRAL_BODY_ORDER));
    // Potential coefficients providers
    final UnnormalizedSphericalHarmonicsProvider unnormalized = GravityFieldFactory.getConstantUnnormalizedProvider(degree, order);
    final NormalizedSphericalHarmonicsProvider normalized = GravityFieldFactory.getConstantNormalizedProvider(degree, order);
    // Central body attraction coefficient (m³/s²)
    final double mu = unnormalized.getMu();
    // Earth frame definition
    final Frame earthFrame;
    if (!parser.containsKey(ParameterKey.BODY_FRAME)) {
        earthFrame = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
    } else {
        earthFrame = parser.getEarthFrame(ParameterKey.BODY_FRAME);
    }
    // Orbit definition
    final Orbit orbit = createOrbit(parser, utc, mu);
    // DSST propagator definition
    double mass = 1000.0;
    if (parser.containsKey(ParameterKey.MASS)) {
        mass = parser.getDouble(ParameterKey.MASS);
    }
    boolean initialIsOsculating = false;
    if (parser.containsKey(ParameterKey.INITIAL_ORBIT_IS_OSCULATING)) {
        initialIsOsculating = parser.getBoolean(ParameterKey.INITIAL_ORBIT_IS_OSCULATING);
    }
    boolean outputIsOsculating = initialIsOsculating;
    if (parser.containsKey(ParameterKey.OUTPUT_ORBIT_IS_OSCULATING)) {
        outputIsOsculating = parser.getBoolean(ParameterKey.OUTPUT_ORBIT_IS_OSCULATING);
    }
    List<String> shortPeriodCoefficients = null;
    if (parser.containsKey(ParameterKey.OUTPUT_SHORT_PERIOD_COEFFICIENTS)) {
        shortPeriodCoefficients = parser.getStringsList(ParameterKey.OUTPUT_SHORT_PERIOD_COEFFICIENTS, ',');
        if (shortPeriodCoefficients.size() == 1 && shortPeriodCoefficients.get(0).equalsIgnoreCase("all")) {
            // special case, we use the empty list to represent all possible (unknown) keys
            // we don't use Collections.emptyList() because we want the list to be populated later on
            shortPeriodCoefficients = new ArrayList<String>();
        } else if (shortPeriodCoefficients.size() == 1 && shortPeriodCoefficients.get(0).equalsIgnoreCase("none")) {
            // special case, we use null to select no coefficients at all
            shortPeriodCoefficients = null;
        } else {
            // general case, we have an explicit list of coefficients names
            Collections.sort(shortPeriodCoefficients);
        }
        if (shortPeriodCoefficients != null && !outputIsOsculating) {
            System.out.println("\nWARNING:");
            System.out.println("Short periodic coefficients can be output only if output orbit is osculating.");
            System.out.println("No coefficients will be computed here.\n");
        }
    }
    double fixedStepSize = -1.;
    double minStep = 6000.0;
    double maxStep = 86400.0;
    double dP = 1.0;
    if (parser.containsKey(ParameterKey.FIXED_INTEGRATION_STEP)) {
        fixedStepSize = parser.getDouble(ParameterKey.FIXED_INTEGRATION_STEP);
    } else {
        if (parser.containsKey(ParameterKey.MIN_VARIABLE_INTEGRATION_STEP)) {
            minStep = parser.getDouble(ParameterKey.MIN_VARIABLE_INTEGRATION_STEP);
        }
        if (parser.containsKey(ParameterKey.MAX_VARIABLE_INTEGRATION_STEP)) {
            maxStep = parser.getDouble(ParameterKey.MAX_VARIABLE_INTEGRATION_STEP);
        }
        if (parser.containsKey(ParameterKey.POSITION_TOLERANCE_VARIABLE_INTEGRATION_STEP)) {
            dP = parser.getDouble(ParameterKey.POSITION_TOLERANCE_VARIABLE_INTEGRATION_STEP);
        }
    }
    final DSSTPropagator dsstProp = createDSSTProp(orbit, mass, initialIsOsculating, outputIsOsculating, fixedStepSize, minStep, maxStep, dP, shortPeriodCoefficients);
    if (parser.containsKey(ParameterKey.FIXED_NUMBER_OF_INTERPOLATION_POINTS)) {
        if (parser.containsKey(ParameterKey.MAX_TIME_GAP_BETWEEN_INTERPOLATION_POINTS)) {
            throw new OrekitException(LocalizedCoreFormats.SIMPLE_MESSAGE, "cannot specify both fixed.number.of.interpolation.points" + " and max.time.gap.between.interpolation.points");
        }
        dsstProp.setInterpolationGridToFixedNumberOfPoints(parser.getInt(ParameterKey.FIXED_NUMBER_OF_INTERPOLATION_POINTS));
    } else if (parser.containsKey(ParameterKey.MAX_TIME_GAP_BETWEEN_INTERPOLATION_POINTS)) {
        dsstProp.setInterpolationGridToMaxTimeGap(parser.getDouble(ParameterKey.MAX_TIME_GAP_BETWEEN_INTERPOLATION_POINTS));
    } else {
        dsstProp.setInterpolationGridToFixedNumberOfPoints(3);
    }
    // Set Force models
    setForceModel(parser, unnormalized, earthFrame, rotationRate, dsstProp);
    // Simulation properties
    AbsoluteDate start;
    if (parser.containsKey(ParameterKey.START_DATE)) {
        start = parser.getDate(ParameterKey.START_DATE, utc);
    } else {
        start = parser.getDate(ParameterKey.ORBIT_DATE, utc);
    }
    double duration = 0.;
    if (parser.containsKey(ParameterKey.DURATION)) {
        duration = parser.getDouble(ParameterKey.DURATION);
    }
    if (parser.containsKey(ParameterKey.DURATION_IN_DAYS)) {
        duration = parser.getDouble(ParameterKey.DURATION_IN_DAYS) * Constants.JULIAN_DAY;
    }
    double outStep = parser.getDouble(ParameterKey.OUTPUT_STEP);
    boolean displayKeplerian = true;
    if (parser.containsKey(ParameterKey.OUTPUT_KEPLERIAN)) {
        displayKeplerian = parser.getBoolean(ParameterKey.OUTPUT_KEPLERIAN);
    }
    boolean displayEquinoctial = true;
    if (parser.containsKey(ParameterKey.OUTPUT_EQUINOCTIAL)) {
        displayEquinoctial = parser.getBoolean(ParameterKey.OUTPUT_EQUINOCTIAL);
    }
    boolean displayCartesian = true;
    if (parser.containsKey(ParameterKey.OUTPUT_CARTESIAN)) {
        displayCartesian = parser.getBoolean(ParameterKey.OUTPUT_CARTESIAN);
    }
    // DSST Propagation
    dsstProp.setEphemerisMode();
    final double dsstOn = System.currentTimeMillis();
    dsstProp.propagate(start, start.shiftedBy(duration));
    final double dsstOff = System.currentTimeMillis();
    System.out.println("DSST execution time (without large file write) : " + (dsstOff - dsstOn) / 1000.);
    System.out.println("writing file...");
    final BoundedPropagator dsstEphem = dsstProp.getGeneratedEphemeris();
    dsstEphem.setMasterMode(outStep, new OutputHandler(output, displayKeplerian, displayEquinoctial, displayCartesian, shortPeriodCoefficients));
    dsstEphem.propagate(start, start.shiftedBy(duration));
    System.out.println("DSST results saved as file " + output);
    // Check if we want to compare numerical to DSST propagator (default is false)
    if (parser.containsKey(ParameterKey.NUMERICAL_COMPARISON) && parser.getBoolean(ParameterKey.NUMERICAL_COMPARISON)) {
        if (!outputIsOsculating) {
            System.out.println("\nWARNING:");
            System.out.println("The DSST propagator considers a mean orbit while the numerical will consider an osculating one.");
            System.out.println("The comparison will be meaningless.\n");
        }
        // Numerical propagator definition
        final NumericalPropagator numProp = createNumProp(orbit, mass);
        // Set Force models
        setForceModel(parser, normalized, earthFrame, numProp);
        // Numerical Propagation without output
        numProp.setEphemerisMode();
        final double numOn = System.currentTimeMillis();
        numProp.propagate(start, start.shiftedBy(duration));
        final double numOff = System.currentTimeMillis();
        System.out.println("Numerical execution time (including output): " + (numOff - numOn) / 1000.);
        // Add output
        final BoundedPropagator numEphemeris = numProp.getGeneratedEphemeris();
        File numOutput = new File(input.getParentFile(), "numerical-propagation.out");
        numEphemeris.setMasterMode(outStep, new OutputHandler(numOutput, displayKeplerian, displayEquinoctial, displayCartesian, null));
        System.out.println("Writing file, this may take some time ...");
        numEphemeris.propagate(numEphemeris.getMaxDate());
        System.out.println("Numerical results saved as file " + numOutput);
    }
}