Examples with FieldAbsoluteDate org.orekit.time.FieldAbsoluteDate used on opensource projects

Example 11 with FieldAbsoluteDate

use of org.orekit.time.FieldAbsoluteDate in project Orekit by CS-SI.

the class FieldNumericalPropagatorTest method doTestEphemerisDatesBackward.

private <T extends RealFieldElement<T>> void doTestEphemerisDatesBackward(Field<T> field) throws OrekitException {
    T zero = field.getZero();
    // setup
    TimeScale tai = TimeScalesFactory.getTAI();
    FieldAbsoluteDate<T> initialDate = new FieldAbsoluteDate<>(field, "2015-07-05", tai);
    FieldAbsoluteDate<T> startDate = new FieldAbsoluteDate<>(field, "2015-07-03", tai).shiftedBy(-0.1);
    FieldAbsoluteDate<T> endDate = new FieldAbsoluteDate<>(field, "2015-07-04", tai);
    Frame eci = FramesFactory.getGCRF();
    FieldKeplerianOrbit<T> orbit = new FieldKeplerianOrbit<>(zero.add(600e3 + Constants.WGS84_EARTH_EQUATORIAL_RADIUS), zero, zero, zero, zero, zero, PositionAngle.TRUE, eci, initialDate, mu);
    OrbitType type = OrbitType.CARTESIAN;
    double[][] tol = NumericalPropagator.tolerances(1e-3, orbit.toOrbit(), type);
    FieldNumericalPropagator<T> prop = new FieldNumericalPropagator<>(field, new DormandPrince853FieldIntegrator<>(field, 0.1, 500, tol[0], tol[1]));
    prop.setOrbitType(type);
    prop.resetInitialState(new FieldSpacecraftState<>(new FieldCartesianOrbit<>(orbit)));
    // action
    prop.setEphemerisMode();
    prop.propagate(endDate, startDate);
    FieldBoundedPropagator<T> ephemeris = prop.getGeneratedEphemeris();
    // verify
    TimeStampedFieldPVCoordinates<T> actualPV = ephemeris.getPVCoordinates(startDate, eci);
    TimeStampedFieldPVCoordinates<T> expectedPV = orbit.getPVCoordinates(startDate, eci);
    MatcherAssert.assertThat(actualPV.getPosition().toVector3D(), OrekitMatchers.vectorCloseTo(expectedPV.getPosition().toVector3D(), 1.0));
    MatcherAssert.assertThat(actualPV.getVelocity().toVector3D(), OrekitMatchers.vectorCloseTo(expectedPV.getVelocity().toVector3D(), 1.0));
    MatcherAssert.assertThat(ephemeris.getMinDate().durationFrom(startDate).getReal(), OrekitMatchers.closeTo(0, 0));
    MatcherAssert.assertThat(ephemeris.getMaxDate().durationFrom(endDate).getReal(), OrekitMatchers.closeTo(0, 0));
    // test date
    FieldAbsoluteDate<T> date = endDate.shiftedBy(-0.11);
    Assert.assertEquals(ephemeris.propagate(date).getDate().durationFrom(date).getReal(), 0, 0);
}

Example 12 with FieldAbsoluteDate

use of org.orekit.time.FieldAbsoluteDate in project Orekit by CS-SI.

the class FieldNumericalPropagatorTest method doTestEphemerisDates.

private <T extends RealFieldElement<T>> void doTestEphemerisDates(Field<T> field) throws OrekitException {
    T zero = field.getZero();
    // setup
    TimeScale tai = TimeScalesFactory.getTAI();
    FieldAbsoluteDate<T> initialDate = new FieldAbsoluteDate<>(field, "2015-07-01", tai);
    FieldAbsoluteDate<T> startDate = new FieldAbsoluteDate<>(field, "2015-07-03", tai).shiftedBy(-0.1);
    FieldAbsoluteDate<T> endDate = new FieldAbsoluteDate<>(field, "2015-07-04", tai);
    Frame eci = FramesFactory.getGCRF();
    FieldKeplerianOrbit<T> orbit = new FieldKeplerianOrbit<>(zero.add(600e3 + Constants.WGS84_EARTH_EQUATORIAL_RADIUS), zero, zero, zero, zero, zero, PositionAngle.TRUE, eci, initialDate, mu);
    OrbitType type = OrbitType.CARTESIAN;
    double[][] tol = NumericalPropagator.tolerances(1e-3, orbit.toOrbit(), type);
    FieldNumericalPropagator<T> prop = new FieldNumericalPropagator<>(field, new DormandPrince853FieldIntegrator<>(field, 0.1, 500, tol[0], tol[1]));
    prop.setOrbitType(type);
    prop.resetInitialState(new FieldSpacecraftState<>(new FieldCartesianOrbit<>(orbit)));
    // action
    prop.setEphemerisMode();
    prop.propagate(startDate, endDate);
    FieldBoundedPropagator<T> ephemeris = prop.getGeneratedEphemeris();
    // verify
    TimeStampedFieldPVCoordinates<T> actualPV = ephemeris.getPVCoordinates(startDate, eci);
    TimeStampedFieldPVCoordinates<T> expectedPV = orbit.getPVCoordinates(startDate, eci);
    MatcherAssert.assertThat(actualPV.getPosition().toVector3D(), OrekitMatchers.vectorCloseTo(expectedPV.getPosition().toVector3D(), 1.0));
    MatcherAssert.assertThat(actualPV.getVelocity().toVector3D(), OrekitMatchers.vectorCloseTo(expectedPV.getVelocity().toVector3D(), 1.0));
    MatcherAssert.assertThat(ephemeris.getMinDate().durationFrom(startDate).getReal(), OrekitMatchers.closeTo(0, 0));
    MatcherAssert.assertThat(ephemeris.getMaxDate().durationFrom(endDate).getReal(), OrekitMatchers.closeTo(0, 0));
    // test date
    FieldAbsoluteDate<T> date = endDate.shiftedBy(-0.11);
    Assert.assertEquals(ephemeris.propagate(date).getDate().durationFrom(date).getReal(), 0, 0);
}

Example 13 with FieldAbsoluteDate

use of org.orekit.time.FieldAbsoluteDate in project Orekit by CS-SI.

the class IERSConventionsTest method checkScalarFunctionConsistency.

private void checkScalarFunctionConsistency(final TimeScalarFunction function, final AbsoluteDate date, final double span, final double sampleStep, final double h, final double valueTolerance, final double derivativeTolerance) {
    UnivariateDifferentiableFunction differentiated = new FiniteDifferencesDifferentiator(4, h).differentiate(new UnivariateFunction() {

        @Override
        public double value(final double dt) {
            return function.value(date.shiftedBy(dt));
        }
    });
    DSFactory factory = new DSFactory(1, 1);
    FieldAbsoluteDate<DerivativeStructure> dsDate = new FieldAbsoluteDate<>(date, factory.constant(0.0));
    double maxValueError = 0;
    double maxDerivativeError = 0;
    for (double dt = 0; dt < span; dt += sampleStep) {
        DerivativeStructure dsdt = factory.variable(0, dt);
        DerivativeStructure yRef = differentiated.value(dsdt);
        DerivativeStructure y = function.value(dsDate.shiftedBy(dsdt));
        maxValueError = FastMath.max(maxValueError, FastMath.abs(yRef.getValue() - y.getValue()));
        maxDerivativeError = FastMath.max(maxDerivativeError, FastMath.abs(yRef.getPartialDerivative(1) - y.getPartialDerivative(1)));
    }
    Assert.assertEquals(0, maxValueError, valueTolerance);
    Assert.assertEquals(0, maxDerivativeError, derivativeTolerance);
}

Example 14 with FieldAbsoluteDate

use of org.orekit.time.FieldAbsoluteDate in project Orekit by CS-SI.

the class IERSConventionsTest method checkVectorFunctionConsistency.

private void checkVectorFunctionConsistency(final TimeVectorFunction function, final int dimension, final AbsoluteDate date, final double span, final double sampleStep, final double h, final double valueTolerance, final double derivativeTolerance) {
    UnivariateDifferentiableVectorFunction differentiated = new FiniteDifferencesDifferentiator(4, h).differentiate(new UnivariateVectorFunction() {

        @Override
        public double[] value(final double dt) {
            return function.value(date.shiftedBy(dt));
        }
    });
    DSFactory factory = new DSFactory(1, 1);
    FieldAbsoluteDate<DerivativeStructure> dsDate = new FieldAbsoluteDate<>(date, factory.constant(0.0));
    double maxValueError = 0;
    double maxDerivativeError = 0;
    for (double dt = 0; dt < span; dt += sampleStep) {
        DerivativeStructure dsdt = factory.variable(0, dt);
        DerivativeStructure[] yRef = differentiated.value(dsdt);
        DerivativeStructure[] y = function.value(dsDate.shiftedBy(dsdt));
        Assert.assertEquals(dimension, yRef.length);
        Assert.assertEquals(dimension, y.length);
        for (int i = 0; i < dimension; ++i) {
            maxValueError = FastMath.max(maxValueError, FastMath.abs(yRef[i].getValue() - y[i].getValue()));
            maxDerivativeError = FastMath.max(maxDerivativeError, FastMath.abs(yRef[i].getPartialDerivative(1) - y[i].getPartialDerivative(1)));
        }
    }
    Assert.assertEquals(0, maxValueError, valueTolerance);
    Assert.assertEquals(0, maxDerivativeError, derivativeTolerance);
}

Example 15 with FieldAbsoluteDate

use of org.orekit.time.FieldAbsoluteDate in project Orekit by CS-SI.

the class FieldPropagation method main.

/**
 * Program entry point.
 * @param args program arguments (unused here)
 * @throws IOException
 * @throws OrekitException
 */
public static void main(String[] args) throws IOException, OrekitException {
    // the goal of this example is to make a Montecarlo simulation giving an error on the semiaxis,
    // the inclination and the RAAN. The interest of doing it with Orekit based on the
    // DerivativeStructure is that instead of doing a large number of propagation around the initial
    // point we will do a single propagation of the initial state, and thanks to the Taylor expansion
    // we will see the evolution of the std deviation of the position, which is divided in the
    // CrossTrack, the LongTrack and the Radial error.
    // 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));
    // output file in user's home directory
    File workingDir = new File(System.getProperty("user.home"));
    File errorFile = new File(workingDir, "error.txt");
    System.out.println("Output file is in : " + errorFile.getAbsolutePath());
    PrintWriter PW = new PrintWriter(errorFile, "UTF-8");
    PW.printf("time \t\tCrossTrackErr \tLongTrackErr  \tRadialErr \tTotalErr%n");
    // setting the parameters of the simulation
    // Order of derivation of the DerivativeStructures
    int params = 3;
    int order = 3;
    DSFactory factory = new DSFactory(params, order);
    // number of samples of the montecarlo simulation
    int montecarlo_size = 100;
    // nominal values of the Orbital parameters
    double a_nominal = 7.278E6;
    double e_nominal = 1e-3;
    double i_nominal = FastMath.toRadians(98.3);
    double pa_nominal = FastMath.PI / 2;
    double raan_nominal = 0.0;
    double ni_nominal = 0.0;
    // mean of the gaussian curve for each of the errors around the nominal values
    // {a, i, RAAN}
    double[] mean = { 0, 0, 0 };
    // standard deviation of the gaussian curve for each of the errors around the nominal values
    // {dA, dI, dRaan}
    double[] dAdIdRaan = { 5, FastMath.toRadians(1e-3), FastMath.toRadians(1e-3) };
    // time of integration
    double final_Dt = 1 * 60 * 60;
    // number of steps per orbit
    double num_step_orbit = 10;
    DerivativeStructure a_0 = factory.variable(0, a_nominal);
    DerivativeStructure e_0 = factory.constant(e_nominal);
    DerivativeStructure i_0 = factory.variable(1, i_nominal);
    DerivativeStructure pa_0 = factory.constant(pa_nominal);
    DerivativeStructure raan_0 = factory.variable(2, raan_nominal);
    DerivativeStructure ni_0 = factory.constant(ni_nominal);
    // sometimes we will need the field of the DerivativeStructure to build new instances
    Field<DerivativeStructure> field = a_0.getField();
    // sometimes we will need the zero of the DerivativeStructure to build new instances
    DerivativeStructure zero = field.getZero();
    // initializing the FieldAbsoluteDate with only the field it will generate the day J2000
    FieldAbsoluteDate<DerivativeStructure> date_0 = new FieldAbsoluteDate<>(field);
    // initialize a basic frame
    Frame frame = FramesFactory.getEME2000();
    // initialize the orbit
    double mu = 3.9860047e14;
    FieldKeplerianOrbit<DerivativeStructure> KO = new FieldKeplerianOrbit<>(a_0, e_0, i_0, pa_0, raan_0, ni_0, PositionAngle.ECCENTRIC, frame, date_0, mu);
    // step of integration (how many times per orbit we take the mesures)
    double int_step = KO.getKeplerianPeriod().getReal() / num_step_orbit;
    // random generator to conduct an
    long number = 23091991;
    RandomGenerator RG = new Well19937a(number);
    GaussianRandomGenerator NGG = new GaussianRandomGenerator(RG);
    UncorrelatedRandomVectorGenerator URVG = new UncorrelatedRandomVectorGenerator(mean, dAdIdRaan, NGG);
    double[][] rand_gen = new double[montecarlo_size][3];
    for (int jj = 0; jj < montecarlo_size; jj++) {
        rand_gen[jj] = URVG.nextVector();
    }
    // 
    FieldSpacecraftState<DerivativeStructure> SS_0 = new FieldSpacecraftState<>(KO);
    // adding force models
    ForceModel fModel_Sun = new ThirdBodyAttraction(CelestialBodyFactory.getSun());
    ForceModel fModel_Moon = new ThirdBodyAttraction(CelestialBodyFactory.getMoon());
    ForceModel fModel_HFAM = new HolmesFeatherstoneAttractionModel(FramesFactory.getITRF(IERSConventions.IERS_2010, true), GravityFieldFactory.getNormalizedProvider(18, 18));
    // setting an hipparchus field integrator
    OrbitType type = OrbitType.CARTESIAN;
    double[][] tolerance = NumericalPropagator.tolerances(0.001, KO.toOrbit(), type);
    AdaptiveStepsizeFieldIntegrator<DerivativeStructure> integrator = new DormandPrince853FieldIntegrator<>(field, 0.001, 200, tolerance[0], tolerance[1]);
    integrator.setInitialStepSize(zero.add(60));
    // setting of the field propagator, we used the numerical one in order to add the third body attraction
    // and the holmes featherstone force models
    FieldNumericalPropagator<DerivativeStructure> numProp = new FieldNumericalPropagator<>(field, integrator);
    numProp.setOrbitType(type);
    numProp.setInitialState(SS_0);
    numProp.addForceModel(fModel_Sun);
    numProp.addForceModel(fModel_Moon);
    numProp.addForceModel(fModel_HFAM);
    // with the master mode we will calulcate and print the error on every fixed step on the file error.txt
    // we defined the StepHandler to do that giving him the random number generator,
    // the size of the montecarlo simulation and the initial date
    numProp.setMasterMode(zero.add(int_step), new MyStepHandler<DerivativeStructure>(rand_gen, montecarlo_size, date_0, PW));
    // 
    long START = System.nanoTime();
    FieldSpacecraftState<DerivativeStructure> finalState = numProp.propagate(date_0.shiftedBy(final_Dt));
    long STOP = System.nanoTime();
    System.out.println((STOP - START) / 1E6 + " ms");
    System.out.println(finalState.getDate());
    PW.close();
}