Search in sources :

Example 41 with BoundedPropagator

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

the class AdapterPropagatorTest method testLowEarthOrbit.

@Test
public void testLowEarthOrbit() throws OrekitException, ParseException, IOException {
    Orbit leo = new CircularOrbit(7200000.0, -1.0e-5, 2.0e-4, FastMath.toRadians(98.0), FastMath.toRadians(123.456), 0.0, PositionAngle.MEAN, FramesFactory.getEME2000(), new AbsoluteDate(new DateComponents(2004, 01, 01), new TimeComponents(23, 30, 00.000), TimeScalesFactory.getUTC()), Constants.EIGEN5C_EARTH_MU);
    double mass = 5600.0;
    AbsoluteDate t0 = leo.getDate().shiftedBy(1000.0);
    Vector3D dV = new Vector3D(-0.1, 0.2, 0.3);
    double f = 20.0;
    double isp = 315.0;
    double vExhaust = Constants.G0_STANDARD_GRAVITY * isp;
    double dt = -(mass * vExhaust / f) * FastMath.expm1(-dV.getNorm() / vExhaust);
    BoundedPropagator withoutManeuver = getEphemeris(leo, mass, 5, new LofOffset(leo.getFrame(), LOFType.LVLH), t0, Vector3D.ZERO, f, isp, false, false, null);
    BoundedPropagator withManeuver = getEphemeris(leo, mass, 5, new LofOffset(leo.getFrame(), LOFType.LVLH), t0, dV, f, isp, false, false, null);
    // we set up a model that reverts the maneuvers
    AdapterPropagator adapterPropagator = new AdapterPropagator(withManeuver);
    AdapterPropagator.DifferentialEffect effect = new SmallManeuverAnalyticalModel(adapterPropagator.propagate(t0), dV.negate(), isp);
    adapterPropagator.addEffect(effect);
    adapterPropagator.addAdditionalStateProvider(new AdditionalStateProvider() {

        public String getName() {
            return "dummy 3";
        }

        public double[] getAdditionalState(SpacecraftState state) {
            return new double[3];
        }
    });
    // the adapted propagators do not manage the additional states from the reference,
    // they simply forward them
    Assert.assertFalse(adapterPropagator.isAdditionalStateManaged("dummy 1"));
    Assert.assertFalse(adapterPropagator.isAdditionalStateManaged("dummy 2"));
    Assert.assertTrue(adapterPropagator.isAdditionalStateManaged("dummy 3"));
    for (AbsoluteDate t = t0.shiftedBy(0.5 * dt); t.compareTo(withoutManeuver.getMaxDate()) < 0; t = t.shiftedBy(60.0)) {
        PVCoordinates pvWithout = withoutManeuver.getPVCoordinates(t, leo.getFrame());
        PVCoordinates pvReverted = adapterPropagator.getPVCoordinates(t, leo.getFrame());
        double revertError = new PVCoordinates(pvWithout, pvReverted).getPosition().getNorm();
        Assert.assertEquals(0, revertError, 0.45);
        Assert.assertEquals(2, adapterPropagator.propagate(t).getAdditionalState("dummy 1").length);
        Assert.assertEquals(1, adapterPropagator.propagate(t).getAdditionalState("dummy 2").length);
        Assert.assertEquals(3, adapterPropagator.propagate(t).getAdditionalState("dummy 3").length);
    }
}
Also used : Orbit(org.orekit.orbits.Orbit) CircularOrbit(org.orekit.orbits.CircularOrbit) KeplerianOrbit(org.orekit.orbits.KeplerianOrbit) PVCoordinates(org.orekit.utils.PVCoordinates) DateComponents(org.orekit.time.DateComponents) TimeComponents(org.orekit.time.TimeComponents) AbsoluteDate(org.orekit.time.AbsoluteDate) SpacecraftState(org.orekit.propagation.SpacecraftState) SmallManeuverAnalyticalModel(org.orekit.forces.maneuvers.SmallManeuverAnalyticalModel) CircularOrbit(org.orekit.orbits.CircularOrbit) AdditionalStateProvider(org.orekit.propagation.AdditionalStateProvider) Vector3D(org.hipparchus.geometry.euclidean.threed.Vector3D) BoundedPropagator(org.orekit.propagation.BoundedPropagator) LofOffset(org.orekit.attitudes.LofOffset) Test(org.junit.Test)

Example 42 with BoundedPropagator

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

the class AdapterPropagatorTest method testNonKeplerian.

@Test
public void testNonKeplerian() throws OrekitException, ParseException, IOException {
    Orbit leo = new CircularOrbit(7204319.233600575, 4.434564637450575E-4, 0.0011736728299091088, 1.7211611441767323, 5.5552084166959474, 24950.321259193086, PositionAngle.TRUE, FramesFactory.getEME2000(), new AbsoluteDate(new DateComponents(2003, 9, 16), new TimeComponents(23, 11, 20.264), TimeScalesFactory.getUTC()), Constants.EIGEN5C_EARTH_MU);
    double mass = 4093.0;
    AbsoluteDate t0 = new AbsoluteDate(new DateComponents(2003, 9, 16), new TimeComponents(23, 14, 40.264), TimeScalesFactory.getUTC());
    Vector3D dV = new Vector3D(0.0, 3.0, 0.0);
    double f = 40.0;
    double isp = 300.0;
    double vExhaust = Constants.G0_STANDARD_GRAVITY * isp;
    double dt = -(mass * vExhaust / f) * FastMath.expm1(-dV.getNorm() / vExhaust);
    // setup a specific coefficient file for gravity potential as it will also
    // try to read a corrupted one otherwise
    GravityFieldFactory.addPotentialCoefficientsReader(new ICGEMFormatReader("g007_eigen_05c_coef", false));
    NormalizedSphericalHarmonicsProvider gravityField = GravityFieldFactory.getNormalizedProvider(8, 8);
    BoundedPropagator withoutManeuver = getEphemeris(leo, mass, 10, new LofOffset(leo.getFrame(), LOFType.VNC), t0, Vector3D.ZERO, f, isp, true, true, gravityField);
    BoundedPropagator withManeuver = getEphemeris(leo, mass, 10, new LofOffset(leo.getFrame(), LOFType.VNC), t0, dV, f, isp, true, true, gravityField);
    // we set up a model that reverts the maneuvers
    AdapterPropagator adapterPropagator = new AdapterPropagator(withManeuver);
    SpacecraftState state0 = adapterPropagator.propagate(t0);
    AdapterPropagator.DifferentialEffect directEffect = new SmallManeuverAnalyticalModel(state0, dV.negate(), isp);
    AdapterPropagator.DifferentialEffect derivedEffect = new J2DifferentialEffect(state0, directEffect, false, GravityFieldFactory.getUnnormalizedProvider(gravityField));
    adapterPropagator.addEffect(directEffect);
    adapterPropagator.addEffect(derivedEffect);
    adapterPropagator.addAdditionalStateProvider(new AdditionalStateProvider() {

        public String getName() {
            return "dummy 3";
        }

        public double[] getAdditionalState(SpacecraftState state) {
            return new double[3];
        }
    });
    // the adapted propagators do not manage the additional states from the reference,
    // they simply forward them
    Assert.assertFalse(adapterPropagator.isAdditionalStateManaged("dummy 1"));
    Assert.assertFalse(adapterPropagator.isAdditionalStateManaged("dummy 2"));
    Assert.assertTrue(adapterPropagator.isAdditionalStateManaged("dummy 3"));
    double maxDelta = 0;
    double maxNominal = 0;
    for (AbsoluteDate t = t0.shiftedBy(0.5 * dt); t.compareTo(withoutManeuver.getMaxDate()) < 0; t = t.shiftedBy(600.0)) {
        PVCoordinates pvWithout = withoutManeuver.getPVCoordinates(t, leo.getFrame());
        PVCoordinates pvWith = withManeuver.getPVCoordinates(t, leo.getFrame());
        PVCoordinates pvReverted = adapterPropagator.getPVCoordinates(t, leo.getFrame());
        double nominal = new PVCoordinates(pvWithout, pvWith).getPosition().getNorm();
        double revertError = new PVCoordinates(pvWithout, pvReverted).getPosition().getNorm();
        maxDelta = FastMath.max(maxDelta, revertError);
        maxNominal = FastMath.max(maxNominal, nominal);
        Assert.assertEquals(2, adapterPropagator.propagate(t).getAdditionalState("dummy 1").length);
        Assert.assertEquals(1, adapterPropagator.propagate(t).getAdditionalState("dummy 2").length);
        Assert.assertEquals(3, adapterPropagator.propagate(t).getAdditionalState("dummy 3").length);
    }
    Assert.assertTrue(maxDelta < 120);
    Assert.assertTrue(maxNominal > 2800);
}
Also used : Orbit(org.orekit.orbits.Orbit) CircularOrbit(org.orekit.orbits.CircularOrbit) KeplerianOrbit(org.orekit.orbits.KeplerianOrbit) ICGEMFormatReader(org.orekit.forces.gravity.potential.ICGEMFormatReader) PVCoordinates(org.orekit.utils.PVCoordinates) DateComponents(org.orekit.time.DateComponents) TimeComponents(org.orekit.time.TimeComponents) AbsoluteDate(org.orekit.time.AbsoluteDate) SpacecraftState(org.orekit.propagation.SpacecraftState) SmallManeuverAnalyticalModel(org.orekit.forces.maneuvers.SmallManeuverAnalyticalModel) CircularOrbit(org.orekit.orbits.CircularOrbit) AdditionalStateProvider(org.orekit.propagation.AdditionalStateProvider) Vector3D(org.hipparchus.geometry.euclidean.threed.Vector3D) NormalizedSphericalHarmonicsProvider(org.orekit.forces.gravity.potential.NormalizedSphericalHarmonicsProvider) BoundedPropagator(org.orekit.propagation.BoundedPropagator) LofOffset(org.orekit.attitudes.LofOffset) Test(org.junit.Test)

Example 43 with BoundedPropagator

use of org.orekit.propagation.BoundedPropagator 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;
}
Also used : SpacecraftState(org.orekit.propagation.SpacecraftState) ThirdBodyAttraction(org.orekit.forces.gravity.ThirdBodyAttraction) AdditionalStateProvider(org.orekit.propagation.AdditionalStateProvider) NumericalPropagator(org.orekit.propagation.numerical.NumericalPropagator) AdaptiveStepsizeIntegrator(org.hipparchus.ode.nonstiff.AdaptiveStepsizeIntegrator) DormandPrince853Integrator(org.hipparchus.ode.nonstiff.DormandPrince853Integrator) HolmesFeatherstoneAttractionModel(org.orekit.forces.gravity.HolmesFeatherstoneAttractionModel) BoundedPropagator(org.orekit.propagation.BoundedPropagator) ConstantThrustManeuver(org.orekit.forces.maneuvers.ConstantThrustManeuver)

Example 44 with BoundedPropagator

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

the class AdapterPropagatorTest method testEccentricOrbit.

@Test
public void testEccentricOrbit() throws OrekitException, ParseException, IOException {
    Orbit heo = new KeplerianOrbit(90000000.0, 0.92, FastMath.toRadians(98.0), FastMath.toRadians(12.3456), FastMath.toRadians(123.456), FastMath.toRadians(1.23456), PositionAngle.MEAN, FramesFactory.getEME2000(), new AbsoluteDate(new DateComponents(2004, 01, 01), new TimeComponents(23, 30, 00.000), TimeScalesFactory.getUTC()), Constants.EIGEN5C_EARTH_MU);
    double mass = 5600.0;
    AbsoluteDate t0 = heo.getDate().shiftedBy(1000.0);
    Vector3D dV = new Vector3D(-0.01, 0.02, 0.03);
    double f = 20.0;
    double isp = 315.0;
    double vExhaust = Constants.G0_STANDARD_GRAVITY * isp;
    double dt = -(mass * vExhaust / f) * FastMath.expm1(-dV.getNorm() / vExhaust);
    BoundedPropagator withoutManeuver = getEphemeris(heo, mass, 5, new LofOffset(heo.getFrame(), LOFType.LVLH), t0, Vector3D.ZERO, f, isp, false, false, null);
    BoundedPropagator withManeuver = getEphemeris(heo, mass, 5, new LofOffset(heo.getFrame(), LOFType.LVLH), t0, dV, f, isp, false, false, null);
    // we set up a model that reverts the maneuvers
    AdapterPropagator adapterPropagator = new AdapterPropagator(withManeuver);
    AdapterPropagator.DifferentialEffect effect = new SmallManeuverAnalyticalModel(adapterPropagator.propagate(t0), dV.negate(), isp);
    adapterPropagator.addEffect(effect);
    adapterPropagator.addAdditionalStateProvider(new AdditionalStateProvider() {

        public String getName() {
            return "dummy 3";
        }

        public double[] getAdditionalState(SpacecraftState state) {
            return new double[3];
        }
    });
    // the adapted propagators do not manage the additional states from the reference,
    // they simply forward them
    Assert.assertFalse(adapterPropagator.isAdditionalStateManaged("dummy 1"));
    Assert.assertFalse(adapterPropagator.isAdditionalStateManaged("dummy 2"));
    Assert.assertTrue(adapterPropagator.isAdditionalStateManaged("dummy 3"));
    for (AbsoluteDate t = t0.shiftedBy(0.5 * dt); t.compareTo(withoutManeuver.getMaxDate()) < 0; t = t.shiftedBy(300.0)) {
        PVCoordinates pvWithout = withoutManeuver.getPVCoordinates(t, heo.getFrame());
        PVCoordinates pvReverted = adapterPropagator.getPVCoordinates(t, heo.getFrame());
        double revertError = Vector3D.distance(pvWithout.getPosition(), pvReverted.getPosition());
        Assert.assertEquals(0, revertError, 2.5e-5 * heo.getA());
        Assert.assertEquals(2, adapterPropagator.propagate(t).getAdditionalState("dummy 1").length);
        Assert.assertEquals(1, adapterPropagator.propagate(t).getAdditionalState("dummy 2").length);
        Assert.assertEquals(3, adapterPropagator.propagate(t).getAdditionalState("dummy 3").length);
    }
}
Also used : Orbit(org.orekit.orbits.Orbit) CircularOrbit(org.orekit.orbits.CircularOrbit) KeplerianOrbit(org.orekit.orbits.KeplerianOrbit) PVCoordinates(org.orekit.utils.PVCoordinates) DateComponents(org.orekit.time.DateComponents) TimeComponents(org.orekit.time.TimeComponents) AbsoluteDate(org.orekit.time.AbsoluteDate) SpacecraftState(org.orekit.propagation.SpacecraftState) SmallManeuverAnalyticalModel(org.orekit.forces.maneuvers.SmallManeuverAnalyticalModel) AdditionalStateProvider(org.orekit.propagation.AdditionalStateProvider) Vector3D(org.hipparchus.geometry.euclidean.threed.Vector3D) KeplerianOrbit(org.orekit.orbits.KeplerianOrbit) BoundedPropagator(org.orekit.propagation.BoundedPropagator) LofOffset(org.orekit.attitudes.LofOffset) Test(org.junit.Test)

Example 45 with BoundedPropagator

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

the class EcksteinHechlerPropagatorTest method testIssue224Backward.

@Test
public void testIssue224Backward() throws OrekitException, IOException, ClassNotFoundException {
    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());
    EcksteinHechlerPropagator propagator = new EcksteinHechlerPropagator(initial, new LofOffset(poleAligned, LOFType.VVLH), 1000.0, provider);
    propagator.addAdditionalStateProvider(new SevenProvider());
    propagator.setEphemerisMode();
    // Impulsive burns
    final AbsoluteDate burn1Date = initial.getDate().shiftedBy(-200);
    ImpulseManeuver<DateDetector> impulsiveBurn1 = new ImpulseManeuver<DateDetector>(new DateDetector(burn1Date), new Vector3D(0.0, 500.0, 0.0), 320);
    propagator.addEventDetector(impulsiveBurn1);
    final AbsoluteDate burn2Date = initial.getDate().shiftedBy(-300);
    ImpulseManeuver<DateDetector> impulsiveBurn2 = new ImpulseManeuver<DateDetector>(new DateDetector(burn2Date), new Vector3D(0.0, 500.0, 0.0), 320);
    propagator.addEventDetector(impulsiveBurn2);
    propagator.propagate(initial.getDate().shiftedBy(-400));
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    ObjectOutputStream oos = new ObjectOutputStream(bos);
    oos.writeObject(propagator.getGeneratedEphemeris());
    Assert.assertTrue(bos.size() > 2950);
    Assert.assertTrue(bos.size() < 3050);
    ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
    ObjectInputStream ois = new ObjectInputStream(bis);
    BoundedPropagator ephemeris = (BoundedPropagator) ois.readObject();
    ephemeris.setMasterMode(10, new OrekitFixedStepHandler() {

        public void handleStep(SpacecraftState currentState, boolean isLast) {
            if (currentState.getDate().durationFrom(burn1Date) > 0.001) {
                Assert.assertEquals(97.402, FastMath.toDegrees(currentState.getI()), 1.0e-3);
            } else if (currentState.getDate().durationFrom(burn1Date) < -0.001 && currentState.getDate().durationFrom(burn2Date) > 0.001) {
                Assert.assertEquals(98.164, FastMath.toDegrees(currentState.getI()), 1.0e-3);
            } else if (currentState.getDate().durationFrom(burn2Date) < -0.001) {
                Assert.assertEquals(99.273, FastMath.toDegrees(currentState.getI()), 1.0e-3);
            }
        }
    });
    ephemeris.propagate(ephemeris.getMinDate());
}
Also used : DateDetector(org.orekit.propagation.events.DateDetector) ImpulseManeuver(org.orekit.forces.maneuvers.ImpulseManeuver) Frame(org.orekit.frames.Frame) TopocentricFrame(org.orekit.frames.TopocentricFrame) ByteArrayOutputStream(java.io.ByteArrayOutputStream) ObjectOutputStream(java.io.ObjectOutputStream) Rotation(org.hipparchus.geometry.euclidean.threed.Rotation) FieldAbsoluteDate(org.orekit.time.FieldAbsoluteDate) AbsoluteDate(org.orekit.time.AbsoluteDate) SpacecraftState(org.orekit.propagation.SpacecraftState) CircularOrbit(org.orekit.orbits.CircularOrbit) Vector3D(org.hipparchus.geometry.euclidean.threed.Vector3D) ByteArrayInputStream(java.io.ByteArrayInputStream) Transform(org.orekit.frames.Transform) LofOffset(org.orekit.attitudes.LofOffset) BoundedPropagator(org.orekit.propagation.BoundedPropagator) OrekitFixedStepHandler(org.orekit.propagation.sampling.OrekitFixedStepHandler) ObjectInputStream(java.io.ObjectInputStream) Test(org.junit.Test)

Aggregations

BoundedPropagator (org.orekit.propagation.BoundedPropagator)50 Test (org.junit.Test)44 AbsoluteDate (org.orekit.time.AbsoluteDate)41 SpacecraftState (org.orekit.propagation.SpacecraftState)32 Vector3D (org.hipparchus.geometry.euclidean.threed.Vector3D)20 KeplerianOrbit (org.orekit.orbits.KeplerianOrbit)20 Orbit (org.orekit.orbits.Orbit)19 Frame (org.orekit.frames.Frame)16 CartesianOrbit (org.orekit.orbits.CartesianOrbit)15 CircularOrbit (org.orekit.orbits.CircularOrbit)15 TimeStampedPVCoordinates (org.orekit.utils.TimeStampedPVCoordinates)14 OrekitException (org.orekit.errors.OrekitException)12 PVCoordinates (org.orekit.utils.PVCoordinates)10 Propagator (org.orekit.propagation.Propagator)9 TimeScale (org.orekit.time.TimeScale)9 LofOffset (org.orekit.attitudes.LofOffset)8 FieldAbsoluteDate (org.orekit.time.FieldAbsoluteDate)8 ByteArrayInputStream (java.io.ByteArrayInputStream)7 FieldSpacecraftState (org.orekit.propagation.FieldSpacecraftState)7 ByteArrayOutputStream (java.io.ByteArrayOutputStream)6