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

Example 26 with CircularOrbit

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

the class LofOffsetTest method testOffset.

/**
 * Test if the lof offset is the one expected
 */
@Test
public void testOffset() throws OrekitException {
    // Satellite position
    final CircularOrbit circ = new CircularOrbit(7178000.0, 0.5e-4, -0.5e-4, FastMath.toRadians(0.), FastMath.toRadians(270.), FastMath.toRadians(5.300), PositionAngle.MEAN, FramesFactory.getEME2000(), date, mu);
    // Create target pointing attitude provider
    // ************************************
    // Elliptic earth shape
    final OneAxisEllipsoid earthShape = new OneAxisEllipsoid(6378136.460, 1 / 298.257222101, itrf);
    final GeodeticPoint geoTargetITRF = new GeodeticPoint(FastMath.toRadians(43.36), FastMath.toRadians(1.26), 600.);
    // Attitude law definition from geodetic point target
    final TargetPointing targetLaw = new TargetPointing(circ.getFrame(), geoTargetITRF, earthShape);
    final Rotation targetRot = targetLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    // Create lof aligned attitude provider
    // *******************************
    final LofOffset lofAlignedLaw = new LofOffset(orbit.getFrame(), LOFType.VVLH);
    final Rotation lofAlignedRot = lofAlignedLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    // Get rotation from LOF to target pointing attitude
    Rotation rollPitchYaw = targetRot.compose(lofAlignedRot.revert(), RotationConvention.VECTOR_OPERATOR).revert();
    final double[] angles = rollPitchYaw.getAngles(RotationOrder.ZYX, RotationConvention.VECTOR_OPERATOR);
    final double yaw = angles[0];
    final double pitch = angles[1];
    final double roll = angles[2];
    // Create lof offset attitude provider with computed roll, pitch, yaw
    // **************************************************************
    final LofOffset lofOffsetLaw = new LofOffset(orbit.getFrame(), LOFType.VVLH, RotationOrder.ZYX, yaw, pitch, roll);
    final Rotation lofOffsetRot = lofOffsetLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    // Compose rotations : target pointing attitudes
    final double angleCompo = targetRot.composeInverse(lofOffsetRot, RotationConvention.VECTOR_OPERATOR).getAngle();
    Assert.assertEquals(0., angleCompo, Utils.epsilonAngle);
}

Example 27 with CircularOrbit

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

the class TargetPointingTest method testSlewedTarget.

/**
 * Test the difference between pointing over two longitudes separated by 5°
 */
@Test
public void testSlewedTarget() throws OrekitException {
    // Spheric earth shape
    OneAxisEllipsoid earthShape = new OneAxisEllipsoid(6378136.460, 0., itrf);
    // Satellite position
    // ********************
    // Create satellite position as circular parameters
    CircularOrbit circ = new CircularOrbit(42164000.0, 0.5e-8, -0.5e-8, 0., 0., FastMath.toRadians(5.300), PositionAngle.MEAN, FramesFactory.getEME2000(), date, mu);
    // Create nadir pointing attitude provider
    // **********************************
    NadirPointing nadirAttitudeLaw = new NadirPointing(circ.getFrame(), earthShape);
    // Get observed ground point from nadir pointing law
    Vector3D pNadirObservedEME2000 = nadirAttitudeLaw.getTargetPV(circ, date, FramesFactory.getEME2000()).getPosition();
    Vector3D pNadirObservedITRF = eme2000ToItrf.transformPosition(pNadirObservedEME2000);
    GeodeticPoint geoNadirObserved = earthShape.transform(pNadirObservedITRF, itrf, date);
    // Create target pointing attitude provider with target equal to nadir target
    // *********************************************************************
    TargetPointing targetLawRef = new TargetPointing(circ.getFrame(), itrf, pNadirObservedITRF);
    // Get attitude rotation in EME2000
    Rotation rotSatRefEME2000 = targetLawRef.getAttitude(circ, date, circ.getFrame()).getRotation();
    // Create target pointing attitude provider with target 5° from nadir target
    // ********************************************************************
    GeodeticPoint geoTarget = new GeodeticPoint(geoNadirObserved.getLatitude(), geoNadirObserved.getLongitude() - FastMath.toRadians(5), geoNadirObserved.getAltitude());
    Vector3D pTargetITRF = earthShape.transform(geoTarget);
    TargetPointing targetLaw = new TargetPointing(circ.getFrame(), itrf, pTargetITRF);
    // Get attitude rotation
    Rotation rotSatEME2000 = targetLaw.getAttitude(circ, date, circ.getFrame()).getRotation();
    checkField(Decimal64Field.getInstance(), targetLaw, circ, circ.getDate(), circ.getFrame());
    // Compute difference between both attitude providers
    // *********************************************
    // Difference between attitudes
    // expected
    double tanDeltaExpected = (6378136.460 / (42164000.0 - 6378136.460)) * FastMath.tan(FastMath.toRadians(5));
    double deltaExpected = FastMath.atan(tanDeltaExpected);
    // real
    double deltaReal = Rotation.distance(rotSatEME2000, rotSatRefEME2000);
    Assert.assertEquals(deltaReal, deltaExpected, 1.e-4);
}

Example 28 with CircularOrbit

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

the class OneAxisEllipsoidTest method testIntersectionFromPoints.

@Test
public void testIntersectionFromPoints() throws OrekitException {
    AbsoluteDate date = new AbsoluteDate(new DateComponents(2008, 03, 21), TimeComponents.H12, TimeScalesFactory.getUTC());
    Frame frame = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
    OneAxisEllipsoid earth = new OneAxisEllipsoid(6378136.460, 1 / 298.257222101, frame);
    // Satellite on polar position
    // ***************************
    final double mu = 3.9860047e14;
    CircularOrbit circ = new CircularOrbit(7178000.0, 0.5e-4, 0., FastMath.toRadians(90.), FastMath.toRadians(60.), FastMath.toRadians(90.), PositionAngle.MEAN, FramesFactory.getEME2000(), date, mu);
    // Transform satellite position to position/velocity parameters in EME2000 and ITRF200B
    PVCoordinates pvSatEME2000 = circ.getPVCoordinates();
    PVCoordinates pvSatItrf = frame.getTransformTo(FramesFactory.getEME2000(), date).transformPVCoordinates(pvSatEME2000);
    Vector3D pSatItrf = pvSatItrf.getPosition();
    // Test first visible surface points
    GeodeticPoint geoPoint = new GeodeticPoint(FastMath.toRadians(70.), FastMath.toRadians(60.), 0.);
    Vector3D pointItrf = earth.transform(geoPoint);
    Line line = new Line(pSatItrf, pointItrf, 1.0e-10);
    GeodeticPoint geoInter = earth.getIntersectionPoint(line, pSatItrf, frame, date);
    Assert.assertEquals(geoPoint.getLongitude(), geoInter.getLongitude(), Utils.epsilonAngle);
    Assert.assertEquals(geoPoint.getLatitude(), geoInter.getLatitude(), Utils.epsilonAngle);
    // Test second visible surface points
    geoPoint = new GeodeticPoint(FastMath.toRadians(65.), FastMath.toRadians(-120.), 0.);
    pointItrf = earth.transform(geoPoint);
    line = new Line(pSatItrf, pointItrf, 1.0e-10);
    geoInter = earth.getIntersectionPoint(line, pSatItrf, frame, date);
    Assert.assertEquals(geoPoint.getLongitude(), geoInter.getLongitude(), Utils.epsilonAngle);
    Assert.assertEquals(geoPoint.getLatitude(), geoInter.getLatitude(), Utils.epsilonAngle);
    // Test non visible surface points
    geoPoint = new GeodeticPoint(FastMath.toRadians(30.), FastMath.toRadians(60.), 0.);
    pointItrf = earth.transform(geoPoint);
    line = new Line(pSatItrf, pointItrf, 1.0e-10);
    geoInter = earth.getIntersectionPoint(line, pSatItrf, frame, date);
    // For polar satellite position, intersection point is at the same longitude but different latitude
    Assert.assertEquals(1.04437199, geoInter.getLongitude(), Utils.epsilonAngle);
    Assert.assertEquals(1.36198012, geoInter.getLatitude(), Utils.epsilonAngle);
    // Satellite on equatorial position
    // ********************************
    circ = new CircularOrbit(7178000.0, 0.5e-4, 0., FastMath.toRadians(1.e-4), FastMath.toRadians(0.), FastMath.toRadians(0.), PositionAngle.MEAN, FramesFactory.getEME2000(), date, mu);
    // Transform satellite position to position/velocity parameters in EME2000 and ITRF200B
    pvSatEME2000 = circ.getPVCoordinates();
    pvSatItrf = frame.getTransformTo(FramesFactory.getEME2000(), date).transformPVCoordinates(pvSatEME2000);
    pSatItrf = pvSatItrf.getPosition();
    // Test first visible surface points
    geoPoint = new GeodeticPoint(FastMath.toRadians(5.), FastMath.toRadians(0.), 0.);
    pointItrf = earth.transform(geoPoint);
    line = new Line(pSatItrf, pointItrf, 1.0e-10);
    Assert.assertTrue(line.toSubSpace(pSatItrf).getX() < 0);
    geoInter = earth.getIntersectionPoint(line, pSatItrf, frame, date);
    Assert.assertEquals(geoPoint.getLongitude(), geoInter.getLongitude(), Utils.epsilonAngle);
    Assert.assertEquals(geoPoint.getLatitude(), geoInter.getLatitude(), Utils.epsilonAngle);
    // With the point opposite to satellite point along the line
    GeodeticPoint geoInter2 = earth.getIntersectionPoint(line, line.toSpace(new Vector1D(-line.toSubSpace(pSatItrf).getX())), frame, date);
    Assert.assertTrue(FastMath.abs(geoInter.getLongitude() - geoInter2.getLongitude()) > FastMath.toRadians(0.1));
    Assert.assertTrue(FastMath.abs(geoInter.getLatitude() - geoInter2.getLatitude()) > FastMath.toRadians(0.1));
    // Test second visible surface points
    geoPoint = new GeodeticPoint(FastMath.toRadians(-5.), FastMath.toRadians(0.), 0.);
    pointItrf = earth.transform(geoPoint);
    line = new Line(pSatItrf, pointItrf, 1.0e-10);
    geoInter = earth.getIntersectionPoint(line, pSatItrf, frame, date);
    Assert.assertEquals(geoPoint.getLongitude(), geoInter.getLongitude(), Utils.epsilonAngle);
    Assert.assertEquals(geoPoint.getLatitude(), geoInter.getLatitude(), Utils.epsilonAngle);
    // Test non visible surface points
    geoPoint = new GeodeticPoint(FastMath.toRadians(40.), FastMath.toRadians(0.), 0.);
    pointItrf = earth.transform(geoPoint);
    line = new Line(pSatItrf, pointItrf, 1.0e-10);
    geoInter = earth.getIntersectionPoint(line, pSatItrf, frame, date);
    Assert.assertEquals(-0.00768481, geoInter.getLongitude(), Utils.epsilonAngle);
    Assert.assertEquals(0.32180410, geoInter.getLatitude(), Utils.epsilonAngle);
    // Satellite on any position
    // *************************
    circ = new CircularOrbit(7178000.0, 0.5e-4, 0., FastMath.toRadians(50.), FastMath.toRadians(0.), FastMath.toRadians(90.), PositionAngle.MEAN, FramesFactory.getEME2000(), date, mu);
    // Transform satellite position to position/velocity parameters in EME2000 and ITRF200B
    pvSatEME2000 = circ.getPVCoordinates();
    pvSatItrf = frame.getTransformTo(FramesFactory.getEME2000(), date).transformPVCoordinates(pvSatEME2000);
    pSatItrf = pvSatItrf.getPosition();
    // Test first visible surface points
    geoPoint = new GeodeticPoint(FastMath.toRadians(40.), FastMath.toRadians(90.), 0.);
    pointItrf = earth.transform(geoPoint);
    line = new Line(pSatItrf, pointItrf, 1.0e-10);
    geoInter = earth.getIntersectionPoint(line, pSatItrf, frame, date);
    Assert.assertEquals(geoPoint.getLongitude(), geoInter.getLongitude(), Utils.epsilonAngle);
    Assert.assertEquals(geoPoint.getLatitude(), geoInter.getLatitude(), Utils.epsilonAngle);
    // Test second visible surface points
    geoPoint = new GeodeticPoint(FastMath.toRadians(60.), FastMath.toRadians(90.), 0.);
    pointItrf = earth.transform(geoPoint);
    line = new Line(pSatItrf, pointItrf, 1.0e-10);
    geoInter = earth.getIntersectionPoint(line, pSatItrf, frame, date);
    Assert.assertEquals(geoPoint.getLongitude(), geoInter.getLongitude(), Utils.epsilonAngle);
    Assert.assertEquals(geoPoint.getLatitude(), geoInter.getLatitude(), Utils.epsilonAngle);
    // Test non visible surface points
    geoPoint = new GeodeticPoint(FastMath.toRadians(0.), FastMath.toRadians(90.), 0.);
    pointItrf = earth.transform(geoPoint);
    line = new Line(pSatItrf, pointItrf, 1.0e-10);
    geoInter = earth.getIntersectionPoint(line, pSatItrf, frame, date);
    Assert.assertEquals(FastMath.toRadians(89.5364061088196), geoInter.getLongitude(), Utils.epsilonAngle);
    Assert.assertEquals(FastMath.toRadians(35.555543683351125), geoInter.getLatitude(), Utils.epsilonAngle);
}

Example 29 with CircularOrbit

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

the class TabulatedProviderTest 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());
        // Body mu
        final double mu = 3.9860047e14;
        // Reference frame = ITRF
        itrf = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
        // Satellite position
        circOrbit = 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);
        // Elliptic earth shape
        earthShape = new OneAxisEllipsoid(6378136.460, 1 / 298.257222101, itrf);
    } catch (OrekitException oe) {
        Assert.fail(oe.getMessage());
    }
}

Example 30 with CircularOrbit

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

the class SmallManeuverAnalyticalModelTest method testLowEarthOrbit2.

@Test
public void testLowEarthOrbit2() throws OrekitException {
    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(-0.01, 0.02, 0.03);
    double f = 20.0;
    double isp = 315.0;
    BoundedPropagator withoutManeuver = getEphemeris(leo, mass, t0, Vector3D.ZERO, f, isp);
    BoundedPropagator withManeuver = getEphemeris(leo, mass, t0, dV, f, isp);
    SmallManeuverAnalyticalModel model = new SmallManeuverAnalyticalModel(withoutManeuver.propagate(t0), dV, isp);
    Assert.assertEquals(t0, model.getDate());
    for (AbsoluteDate t = withoutManeuver.getMinDate(); t.compareTo(withoutManeuver.getMaxDate()) < 0; t = t.shiftedBy(60.0)) {
        PVCoordinates pvWithout = withoutManeuver.getPVCoordinates(t, leo.getFrame());
        PVCoordinates pvWith = withManeuver.getPVCoordinates(t, leo.getFrame());
        PVCoordinates pvModel = model.apply(withoutManeuver.propagate(t).getOrbit()).getPVCoordinates(leo.getFrame());
        double nominalDeltaP = new PVCoordinates(pvWith, pvWithout).getPosition().getNorm();
        double modelError = new PVCoordinates(pvWith, pvModel).getPosition().getNorm();
        if (t.compareTo(t0) < 0) {
            // before maneuver, all positions should be equal
            Assert.assertEquals(0, nominalDeltaP, 1.0e-10);
            Assert.assertEquals(0, modelError, 1.0e-10);
        } else {
            // despite nominal deltaP exceeds 1 kilometer after less than 3 orbits
            if (t.durationFrom(t0) > 0.1 * leo.getKeplerianPeriod()) {
                Assert.assertTrue(modelError < 0.009 * nominalDeltaP);
            }
            Assert.assertTrue(modelError < 0.8);
        }
    }
}