Examples with FieldEcksteinHechlerPropagator org.orekit.propagation.analytical.FieldEcksteinHechlerPropagator used on opensource projects

Example 6 with FieldEcksteinHechlerPropagator

use of org.orekit.propagation.analytical.FieldEcksteinHechlerPropagator in project Orekit by CS-SI.

the class AttitudesSequenceTest method doTestDayNightSwitchField.

private <T extends RealFieldElement<T>> void doTestDayNightSwitchField(final Field<T> field) throws OrekitException {
    // Initial state definition : date, orbit
    final FieldAbsoluteDate<T> initialDate = new FieldAbsoluteDate<>(field, 2004, 01, 01, 23, 30, 00.000, TimeScalesFactory.getUTC());
    final FieldVector3D<T> position = new FieldVector3D<>(field, new Vector3D(-6142438.668, 3492467.560, -25767.25680));
    final FieldVector3D<T> velocity = new FieldVector3D<>(field, new Vector3D(505.8479685, 942.7809215, 7435.922231));
    final FieldOrbit<T> initialOrbit = new FieldKeplerianOrbit<>(new FieldPVCoordinates<>(position, velocity), FramesFactory.getEME2000(), initialDate, Constants.EIGEN5C_EARTH_MU);
    // Attitudes sequence definition
    EventsLogger logger = new EventsLogger();
    final AttitudesSequence attitudesSequence = new AttitudesSequence();
    final AttitudeProvider dayObservationLaw = new LofOffset(initialOrbit.getFrame(), LOFType.VVLH, RotationOrder.XYZ, FastMath.toRadians(20), FastMath.toRadians(40), 0);
    final AttitudeProvider nightRestingLaw = new LofOffset(initialOrbit.getFrame(), LOFType.VVLH);
    final PVCoordinatesProvider sun = CelestialBodyFactory.getSun();
    final PVCoordinatesProvider earth = CelestialBodyFactory.getEarth();
    final EclipseDetector ed = new EclipseDetector(sun, 696000000., earth, Constants.WGS84_EARTH_EQUATORIAL_RADIUS).withHandler(new ContinueOnEvent<EclipseDetector>() {

        private static final long serialVersionUID = 1L;

        int count = 0;

        public EventHandler.Action eventOccurred(final SpacecraftState s, final EclipseDetector d, final boolean increasing) {
            setInEclipse(s.getDate(), !increasing);
            if (count++ == 7) {
                return Action.STOP;
            } else {
                switch(count % 3) {
                    case 0:
                        return Action.CONTINUE;
                    case 1:
                        return Action.RESET_DERIVATIVES;
                    default:
                        return Action.RESET_STATE;
                }
            }
        }
    });
    final EventDetector monitored = logger.monitorDetector(ed);
    final Handler dayToNightHandler = new Handler(dayObservationLaw, nightRestingLaw);
    final Handler nightToDayHandler = new Handler(nightRestingLaw, dayObservationLaw);
    attitudesSequence.addSwitchingCondition(dayObservationLaw, nightRestingLaw, monitored, false, true, 300.0, AngularDerivativesFilter.USE_RRA, dayToNightHandler);
    attitudesSequence.addSwitchingCondition(nightRestingLaw, dayObservationLaw, monitored, true, false, 300.0, AngularDerivativesFilter.USE_RRA, nightToDayHandler);
    FieldSpacecraftState<T> initialState = new FieldSpacecraftState<>(initialOrbit);
    initialState = initialState.addAdditionalState("fortyTwo", field.getZero().add(42.0));
    if (ed.g(initialState.toSpacecraftState()) >= 0) {
        // initial position is in daytime
        setInEclipse(initialDate.toAbsoluteDate(), false);
        attitudesSequence.resetActiveProvider(dayObservationLaw);
    } else {
        // initial position is in nighttime
        setInEclipse(initialDate.toAbsoluteDate(), true);
        attitudesSequence.resetActiveProvider(nightRestingLaw);
    }
    // Propagator : consider the analytical Eckstein-Hechler model
    final FieldPropagator<T> propagator = new FieldEcksteinHechlerPropagator<T>(initialOrbit, attitudesSequence, Constants.EIGEN5C_EARTH_EQUATORIAL_RADIUS, Constants.EIGEN5C_EARTH_MU, Constants.EIGEN5C_EARTH_C20, Constants.EIGEN5C_EARTH_C30, Constants.EIGEN5C_EARTH_C40, Constants.EIGEN5C_EARTH_C50, Constants.EIGEN5C_EARTH_C60);
    // Register the switching events to the propagator
    attitudesSequence.registerSwitchEvents(field, propagator);
    propagator.setMasterMode(field.getZero().add(60.0), new FieldOrekitFixedStepHandler<T>() {

        public void handleStep(FieldSpacecraftState<T> currentState, boolean isLast) throws OrekitException {
            // the Earth position in spacecraft frame should be along spacecraft Z axis
            // during night time and away from it during day time due to roll and pitch offsets
            final FieldVector3D<T> earth = currentState.toTransform().transformPosition(Vector3D.ZERO);
            final T pointingOffset = FieldVector3D.angle(earth, Vector3D.PLUS_K);
            // the g function is the eclipse indicator, its an angle between Sun and Earth limb,
            // positive when Sun is outside of Earth limb, negative when Sun is hidden by Earth limb
            final double eclipseAngle = ed.g(currentState.toSpacecraftState());
            if (currentState.getDate().durationFrom(lastChange).getReal() > 300) {
                if (inEclipse) {
                    Assert.assertTrue(eclipseAngle <= 0);
                    Assert.assertEquals(0.0, pointingOffset.getReal(), 1.0e-6);
                } else {
                    Assert.assertTrue(eclipseAngle >= 0);
                    Assert.assertEquals(0.767215, pointingOffset.getReal(), 1.0e-6);
                }
            } else {
                // we are in transition
                Assert.assertTrue(pointingOffset.getReal() + " " + (0.767215 - pointingOffset.getReal()), pointingOffset.getReal() <= 0.7672155);
            }
        }
    });
    // Propagate from the initial date for the fixed duration
    propagator.propagate(initialDate.shiftedBy(12600.));
    // as we have 2 switch events (even if they share the same underlying event detector),
    // and these events are triggered at both eclipse entry and exit, we get 8
    // raw events on 2 orbits
    Assert.assertEquals(8, logger.getLoggedEvents().size());
    // we have 4 attitudes switch on 2 orbits, 2 of each type
    Assert.assertEquals(2, dayToNightHandler.dates.size());
    Assert.assertEquals(2, nightToDayHandler.dates.size());
}