Examples with CircularOrbit org.orekit.orbits.CircularOrbit used on opensource projects

Example 21 with CircularOrbit

use of org.orekit.orbits.CircularOrbit in project Orekit by CS-SI.

the class NadirPointingTest method testSphericEarth.

/**
 * Test in the case of a spheric earth : nadir pointing shall be
 * the same as earth center pointing
 */
@Test
public void testSphericEarth() throws OrekitException {
    // Spheric earth shape
    OneAxisEllipsoid earthShape = new OneAxisEllipsoid(6378136.460, 0., itrf);
    // Create nadir pointing attitude provider
    NadirPointing nadirAttitudeLaw = new NadirPointing(FramesFactory.getEME2000(), earthShape);
    // Create earth center pointing attitude provider
    BodyCenterPointing earthCenterAttitudeLaw = new BodyCenterPointing(FramesFactory.getEME2000(), earthShape);
    // Create satellite position as circular parameters
    CircularOrbit circ = new CircularOrbit(7178000.0, 0.5e-4, -0.5e-4, FastMath.toRadians(50.), FastMath.toRadians(270.), FastMath.toRadians(5.300), PositionAngle.MEAN, FramesFactory.getEME2000(), date, mu);
    // Get nadir attitude
    Rotation rotNadir = nadirAttitudeLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    // Get earth center attitude
    Rotation rotCenter = earthCenterAttitudeLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    // For a spheric earth, earth center pointing attitude and nadir pointing attitude
    // shall be the same, i.e the composition of inverse earth pointing rotation
    // with nadir pointing rotation shall be identity.
    Rotation rotCompo = rotCenter.composeInverse(rotNadir, RotationConvention.VECTOR_OPERATOR);
    double angle = rotCompo.getAngle();
    Assert.assertEquals(angle, 0.0, Utils.epsilonAngle);
}

Example 22 with CircularOrbit

use of org.orekit.orbits.CircularOrbit in project Orekit by CS-SI.

the class NadirPointingTest method testNonSphericEarth.

/**
 * Test in the case of an elliptic earth : nadir pointing shall be :
 *   - the same as earth center pointing in case of equatorial or polar position
 *   - different from earth center pointing in any other case
 */
@Test
public void testNonSphericEarth() throws OrekitException {
    // Elliptic earth shape
    OneAxisEllipsoid earthShape = new OneAxisEllipsoid(6378136.460, 1 / 298.257222101, itrf);
    // Create nadir pointing attitude provider
    NadirPointing nadirAttitudeLaw = new NadirPointing(FramesFactory.getEME2000(), earthShape);
    // Create earth center pointing attitude provider
    BodyCenterPointing earthCenterAttitudeLaw = new BodyCenterPointing(FramesFactory.getEME2000(), earthShape);
    // Satellite on equatorial position
    // **********************************
    KeplerianOrbit kep = new KeplerianOrbit(7178000.0, 1.e-8, FastMath.toRadians(50.), 0., 0., 0., PositionAngle.TRUE, FramesFactory.getEME2000(), date, mu);
    // Get nadir attitude
    Rotation rotNadir = nadirAttitudeLaw.getAttitude(kep, date, kep.getFrame()).getRotation();
    checkField(Decimal64Field.getInstance(), nadirAttitudeLaw, kep, kep.getDate(), kep.getFrame());
    // Get earth center attitude
    Rotation rotCenter = earthCenterAttitudeLaw.getAttitude(kep, date, kep.getFrame()).getRotation();
    // For a satellite at equatorial position, earth center pointing attitude and nadir pointing
    // attitude shall be the same, i.e the composition of inverse earth pointing rotation
    // with nadir pointing rotation shall be identity.
    Rotation rotCompo = rotCenter.composeInverse(rotNadir, RotationConvention.VECTOR_OPERATOR);
    double angle = rotCompo.getAngle();
    Assert.assertEquals(0.0, angle, 5.e-6);
    // Satellite on polar position
    // *****************************
    CircularOrbit circ = new CircularOrbit(7178000.0, 1.e-5, 0., FastMath.toRadians(90.), 0., FastMath.toRadians(90.), PositionAngle.TRUE, FramesFactory.getEME2000(), date, mu);
    // Get nadir attitude
    rotNadir = nadirAttitudeLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    // Get earth center attitude
    rotCenter = earthCenterAttitudeLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    // For a satellite at polar position, earth center pointing attitude and nadir pointing
    // attitude shall be the same, i.e the composition of inverse earth pointing rotation
    // with nadir pointing rotation shall be identity.
    rotCompo = rotCenter.composeInverse(rotNadir, RotationConvention.VECTOR_OPERATOR);
    angle = rotCompo.getAngle();
    Assert.assertEquals(angle, 0.0, 5.e-6);
    // Satellite on any position
    // ***************************
    circ = new CircularOrbit(7178000.0, 1.e-5, 0., FastMath.toRadians(50.), 0., FastMath.toRadians(90.), PositionAngle.TRUE, FramesFactory.getEME2000(), date, mu);
    // Get nadir attitude
    rotNadir = nadirAttitudeLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    // Get earth center attitude
    rotCenter = earthCenterAttitudeLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    // For a satellite at any position, earth center pointing attitude and nadir pointing
    // and nadir pointing attitude shall not be the same, i.e the composition of inverse earth
    // pointing rotation with nadir pointing rotation shall be different from identity.
    rotCompo = rotCenter.composeInverse(rotNadir, RotationConvention.VECTOR_OPERATOR);
    angle = rotCompo.getAngle();
    Assert.assertEquals(angle, FastMath.toRadians(0.16797386586252272), Utils.epsilonAngle);
}

Example 23 with CircularOrbit

use of org.orekit.orbits.CircularOrbit in project Orekit by CS-SI.

the class NadirPointingTest method testVertical.

/**
 * Vertical test : check that Z satellite axis is collinear to local vertical axis,
 *        which direction is : (cos(lon)*cos(lat), sin(lon)*cos(lat), sin(lat)),
 *        where lon et lat stand for observed point coordinates
 *        (i.e satellite ones, since they are the same by construction,
 *        but that's what is to test.
 */
@Test
public void testVertical() throws OrekitException {
    // Elliptic earth shape
    OneAxisEllipsoid earthShape = new OneAxisEllipsoid(6378136.460, 1 / 298.257222101, itrf);
    // Create earth center pointing attitude provider
    NadirPointing nadirAttitudeLaw = new NadirPointing(FramesFactory.getEME2000(), earthShape);
    // Satellite on any position
    CircularOrbit circ = new CircularOrbit(7178000.0, 1.e-5, 0., FastMath.toRadians(50.), 0., FastMath.toRadians(90.), PositionAngle.TRUE, FramesFactory.getEME2000(), date, mu);
    // Vertical test
    // ***************
    // Get observed ground point position/velocity
    TimeStampedPVCoordinates pvTargetItrf = nadirAttitudeLaw.getTargetPV(circ, date, itrf);
    // Convert to geodetic coordinates
    GeodeticPoint geoTarget = earthShape.transform(pvTargetItrf.getPosition(), itrf, date);
    // Compute local vertical axis
    double xVert = FastMath.cos(geoTarget.getLongitude()) * FastMath.cos(geoTarget.getLatitude());
    double yVert = FastMath.sin(geoTarget.getLongitude()) * FastMath.cos(geoTarget.getLatitude());
    double zVert = FastMath.sin(geoTarget.getLatitude());
    Vector3D targetVertical = new Vector3D(xVert, yVert, zVert);
    // Get attitude rotation state
    Rotation rotSatEME2000 = nadirAttitudeLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    // Get satellite Z axis in EME2000 frame
    Vector3D zSatEME2000 = rotSatEME2000.applyInverseTo(Vector3D.PLUS_K);
    Vector3D zSatItrf = FramesFactory.getEME2000().getTransformTo(itrf, date).transformVector(zSatEME2000);
    // Check that satellite Z axis is collinear to local vertical axis
    double angle = Vector3D.angle(zSatItrf, targetVertical);
    Assert.assertEquals(0.0, FastMath.sin(angle), Utils.epsilonTest);
}

Example 24 with CircularOrbit

use of org.orekit.orbits.CircularOrbit in project Orekit by CS-SI.

the class NadirPointingTest method testSlidingDerivatives.

/**
 * Test the derivatives of the sliding target
 */
@Test
public void testSlidingDerivatives() throws OrekitException {
    // Elliptic earth shape
    OneAxisEllipsoid earthShape = new OneAxisEllipsoid(6378136.460, 1 / 298.257222101, itrf);
    // Create earth center pointing attitude provider
    NadirPointing nadirAttitudeLaw = new NadirPointing(FramesFactory.getEME2000(), earthShape);
    // Satellite on any position
    CircularOrbit circ = new CircularOrbit(7178000.0, 1.e-5, 0., FastMath.toRadians(50.), 0., FastMath.toRadians(90.), PositionAngle.TRUE, FramesFactory.getEME2000(), date, mu);
    List<TimeStampedPVCoordinates> sample = new ArrayList<TimeStampedPVCoordinates>();
    for (double dt = -0.1; dt < 0.1; dt += 0.05) {
        Orbit o = circ.shiftedBy(dt);
        sample.add(nadirAttitudeLaw.getTargetPV(o, o.getDate(), o.getFrame()));
    }
    TimeStampedPVCoordinates reference = TimeStampedPVCoordinates.interpolate(circ.getDate(), CartesianDerivativesFilter.USE_P, sample);
    TimeStampedPVCoordinates target = nadirAttitudeLaw.getTargetPV(circ, circ.getDate(), circ.getFrame());
    Assert.assertEquals(0.0, Vector3D.distance(reference.getPosition(), target.getPosition()), 1.0e-15 * reference.getPosition().getNorm());
    Assert.assertEquals(0.0, Vector3D.distance(reference.getVelocity(), target.getVelocity()), 3.0e-11 * reference.getVelocity().getNorm());
    Assert.assertEquals(0.0, Vector3D.distance(reference.getAcceleration(), target.getAcceleration()), 1.3e-5 * reference.getAcceleration().getNorm());
}

Example 25 with CircularOrbit

use of org.orekit.orbits.CircularOrbit in project Orekit by CS-SI.

the class BodyCenterPointingTest method setUp.

@Before
public void setUp() {
    try {
        Utils.setDataRoot("regular-data");
        // Computation date
        date = new AbsoluteDate(new DateComponents(2008, 04, 07), TimeComponents.H00, TimeScalesFactory.getUTC());
        // Satellite position as circular parameters
        final double mu = 3.9860047e14;
        final double raan = 270.;
        circ = new CircularOrbit(7178000.0, 0.5e-4, -0.5e-4, FastMath.toRadians(50.), FastMath.toRadians(raan), FastMath.toRadians(5.300 - raan), PositionAngle.MEAN, FramesFactory.getEME2000(), date, mu);
        // WGS84 Earth model
        earth = new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, FramesFactory.getITRF(IERSConventions.IERS_2010, true));
        // Transform from EME2000 to ITRF2008
        eme2000ToItrf = FramesFactory.getEME2000().getTransformTo(earth.getBodyFrame(), date);
        // Create earth center pointing attitude provider
        earthCenterAttitudeLaw = new BodyCenterPointing(circ.getFrame(), earth);
    } catch (OrekitException oe) {
        Assert.fail(oe.getMessage());
    }
}