Examples with LofOffset org.orekit.attitudes.LofOffset used on opensource projects

Example 41 with LofOffset

use of org.orekit.attitudes.LofOffset in project Orekit by CS-SI.

the class RelativityTest method testAccelerationCircular.

/**
 * Check a nearly circular orbit.
 *
 * @throws OrekitException on error
 */
@Test
public void testAccelerationCircular() throws OrekitException {
    double gm = Constants.EIGEN5C_EARTH_MU;
    double re = Constants.WGS84_EARTH_EQUATORIAL_RADIUS;
    Relativity relativity = new Relativity(gm);
    final CircularOrbit orbit = new CircularOrbit(re + 500e3, 0, 0, FastMath.toRadians(41.2), -1, 3, PositionAngle.TRUE, frame, date, gm);
    SpacecraftState state = new SpacecraftState(orbit);
    // action
    Vector3D acceleration = relativity.acceleration(state, relativity.getParameters());
    // verify
    // force is ~1e-8 so this give ~7 sig figs.
    double tol = 2e-10;
    PVCoordinates pv = state.getPVCoordinates();
    Vector3D p = pv.getPosition();
    Vector3D v = pv.getVelocity();
    Vector3D circularApproximation = p.normalize().scalarMultiply(gm / p.getNormSq() * 3 * v.getNormSq() / (c * c));
    Assert.assertEquals(0, acceleration.subtract(circularApproximation).getNorm(), tol);
    // check derivatives
    FieldSpacecraftState<DerivativeStructure> sDS = toDS(state, new LofOffset(state.getFrame(), LOFType.VVLH));
    FieldVector3D<DerivativeStructure> gradient = relativity.acceleration(sDS, relativity.getParameters(sDS.getDate().getField()));
    Assert.assertEquals(0, gradient.toVector3D().subtract(circularApproximation).getNorm(), tol);
    double r = p.getNorm();
    double s = v.getNorm();
    final double[] actualdx = gradient.getX().getAllDerivatives();
    final double x = p.getX();
    final double vx = v.getX();
    double expectedDxDx = gm / (c * c * r * r * r * r * r) * (-13 * x * x * s * s + 3 * r * r * s * s + 4 * r * r * vx * vx);
    Assert.assertEquals(expectedDxDx, actualdx[1], 2);
}

Example 42 with LofOffset

use of org.orekit.attitudes.LofOffset in project Orekit by CS-SI.

the class SolidTidesTest method testStateJacobianVs80ImplementationPoleTide.

@Test
public void testStateJacobianVs80ImplementationPoleTide() throws OrekitException {
    Frame eme2000 = FramesFactory.getEME2000();
    TimeScale utc = TimeScalesFactory.getUTC();
    AbsoluteDate date = new AbsoluteDate(2964, 8, 12, 11, 30, 00.000, utc);
    Orbit orbit = new KeplerianOrbit(7201009.7124401, 1e-3, FastMath.toRadians(98.7), FastMath.toRadians(93.0), FastMath.toRadians(15.0 * 22.5), 0, PositionAngle.MEAN, eme2000, date, Constants.EIGEN5C_EARTH_MU);
    Frame itrf = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
    UT1Scale ut1 = TimeScalesFactory.getUT1(IERSConventions.IERS_2010, true);
    NormalizedSphericalHarmonicsProvider gravityField = GravityFieldFactory.getConstantNormalizedProvider(5, 5);
    ForceModel forceModel = new SolidTides(itrf, gravityField.getAe(), gravityField.getMu(), gravityField.getTideSystem(), true, SolidTides.DEFAULT_STEP, SolidTides.DEFAULT_POINTS, IERSConventions.IERS_2010, ut1, CelestialBodyFactory.getSun(), CelestialBodyFactory.getMoon());
    checkStateJacobianVs80Implementation(new SpacecraftState(orbit), forceModel, new LofOffset(orbit.getFrame(), LOFType.VVLH), 2.0e-15, false);
}

Example 43 with LofOffset

use of org.orekit.attitudes.LofOffset in project Orekit by CS-SI.

the class ThirdBodyAttractionTest method testJacobianVs80Implementation.

@Test
public void testJacobianVs80Implementation() 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);
    final CelestialBody moon = CelestialBodyFactory.getMoon();
    final ThirdBodyAttraction forceModel = new ThirdBodyAttraction(moon);
    checkStateJacobianVs80Implementation(new SpacecraftState(orbit), forceModel, new LofOffset(orbit.getFrame(), LOFType.VVLH), 1.0e-50, false);
}

Example 44 with LofOffset

use of org.orekit.attitudes.LofOffset in project Orekit by CS-SI.

the class OnBoardAntennaInterSatellitesRangeModifierTest method testEffect.

@Test
public void testEffect() throws OrekitException {
    Context context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
    final NumericalPropagatorBuilder propagatorBuilder = context.createBuilder(OrbitType.KEPLERIAN, PositionAngle.TRUE, true, 1.0e-6, 60.0, 0.001);
    propagatorBuilder.setAttitudeProvider(new LofOffset(propagatorBuilder.getFrame(), LOFType.LVLH));
    // create perfect inter-satellites range measurements without antenna offset
    final TimeStampedPVCoordinates original = context.initialOrbit.getPVCoordinates();
    final Orbit closeOrbit = new CartesianOrbit(new TimeStampedPVCoordinates(context.initialOrbit.getDate(), original.getPosition().add(new Vector3D(1000, 2000, 3000)), original.getVelocity().add(new Vector3D(-0.03, 0.01, 0.02))), context.initialOrbit.getFrame(), context.initialOrbit.getMu());
    final Propagator closePropagator = EstimationTestUtils.createPropagator(closeOrbit, propagatorBuilder);
    closePropagator.setEphemerisMode();
    closePropagator.propagate(context.initialOrbit.getDate().shiftedBy(3.5 * closeOrbit.getKeplerianPeriod()));
    final BoundedPropagator ephemeris = closePropagator.getGeneratedEphemeris();
    final Propagator p1 = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    final List<ObservedMeasurement<?>> spacecraftCenteredMeasurements = EstimationTestUtils.createMeasurements(p1, new InterSatellitesRangeMeasurementCreator(ephemeris, Vector3D.ZERO, Vector3D.ZERO), 1.0, 3.0, 300.0);
    // create perfect inter-satellites range measurements with antenna offset
    final Vector3D apc1 = new Vector3D(-2.5, 0.0, 0);
    final Vector3D apc2 = new Vector3D(0.0, 0.8, 0);
    final Propagator p2 = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    final List<ObservedMeasurement<?>> antennaCenteredMeasurements = EstimationTestUtils.createMeasurements(p2, new InterSatellitesRangeMeasurementCreator(ephemeris, apc1, apc2), 1.0, 3.0, 300.0);
    final Propagator p3 = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    OnBoardAntennaInterSatellitesRangeModifier modifier = new OnBoardAntennaInterSatellitesRangeModifier(apc1, apc2);
    for (int i = 0; i < spacecraftCenteredMeasurements.size(); ++i) {
        InterSatellitesRange sr = (InterSatellitesRange) spacecraftCenteredMeasurements.get(i);
        sr.addModifier(modifier);
        EstimatedMeasurement<InterSatellitesRange> estimated = sr.estimate(0, 0, new SpacecraftState[] { p3.propagate(sr.getDate()), ephemeris.propagate(sr.getDate()) });
        InterSatellitesRange ar = (InterSatellitesRange) antennaCenteredMeasurements.get(i);
        Assert.assertEquals(0.0, sr.getDate().durationFrom(ar.getDate()), 2.0e-8);
        Assert.assertEquals(ar.getObservedValue()[0], estimated.getEstimatedValue()[0], 2.0e-5);
    }
}

Example 45 with LofOffset

use of org.orekit.attitudes.LofOffset in project Orekit by CS-SI.

the class OnBoardAntennaRangeModifierTest method testEffect.

@Test
public void testEffect() throws OrekitException {
    Context context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
    final NumericalPropagatorBuilder propagatorBuilder = context.createBuilder(OrbitType.KEPLERIAN, PositionAngle.TRUE, true, 1.0e-6, 60.0, 0.001);
    propagatorBuilder.setAttitudeProvider(new LofOffset(propagatorBuilder.getFrame(), LOFType.LVLH));
    // create perfect range measurements without antenna offset
    final Propagator p1 = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    final List<ObservedMeasurement<?>> spacecraftCenteredMeasurements = EstimationTestUtils.createMeasurements(p1, new RangeMeasurementCreator(context, Vector3D.ZERO), 1.0, 3.0, 300.0);
    // create perfect range measurements with antenna offset
    final Vector3D apc = new Vector3D(-2.5, 0, 0);
    final Propagator p2 = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    final List<ObservedMeasurement<?>> antennaCenteredMeasurements = EstimationTestUtils.createMeasurements(p2, new RangeMeasurementCreator(context, apc), 1.0, 3.0, 300.0);
    final Propagator p3 = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    OnBoardAntennaRangeModifier modifier = new OnBoardAntennaRangeModifier(apc);
    for (int i = 0; i < spacecraftCenteredMeasurements.size(); ++i) {
        Range sr = (Range) spacecraftCenteredMeasurements.get(i);
        sr.addModifier(modifier);
        EstimatedMeasurement<Range> estimated = sr.estimate(0, 0, new SpacecraftState[] { p3.propagate(sr.getDate()) });
        Range ar = (Range) antennaCenteredMeasurements.get(i);
        Assert.assertEquals(0.0, sr.getDate().durationFrom(ar.getDate()), 1.0e-8);
        Assert.assertEquals(ar.getObservedValue()[0], estimated.getEstimatedValue()[0], 2.6e-7);
    }
}