Examples with GroundFieldOfViewDetector org.orekit.propagation.events.GroundFieldOfViewDetector used on opensource projects

Example 1 with GroundFieldOfViewDetector

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

the class GroundFieldOfViewDetectorTest method testCaseSimilarToElevationDetector.

/**
 * Check FoV detector is similar to {@link ElevationDetector} when using
 * zenith pointing.
 *
 * @throws OrekitException on error.
 */
@Test
public void testCaseSimilarToElevationDetector() throws OrekitException {
    // setup
    double pi = FastMath.PI;
    // arbitrary date
    AbsoluteDate date = AbsoluteDate.J2000_EPOCH;
    AbsoluteDate endDate = date.shiftedBy(Constants.JULIAN_DAY);
    Frame eci = FramesFactory.getGCRF();
    Frame ecef = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
    BodyShape earth = new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, ecef);
    GeodeticPoint gp = new GeodeticPoint(FastMath.toRadians(39), FastMath.toRadians(77), 0);
    TopocentricFrame topo = new TopocentricFrame(earth, gp, "topo");
    // iss like orbit
    KeplerianOrbit orbit = new KeplerianOrbit(6378137 + 400e3, 0, FastMath.toRadians(51.65), 0, 0, 0, PositionAngle.TRUE, eci, date, Constants.EGM96_EARTH_MU);
    Propagator prop = new KeplerianPropagator(orbit);
    // compute expected result
    ElevationDetector elevationDetector = new ElevationDetector(topo).withConstantElevation(pi / 6).withMaxCheck(5.0);
    EventsLogger logger = new EventsLogger();
    prop.addEventDetector(logger.monitorDetector(elevationDetector));
    prop.propagate(endDate);
    List<LoggedEvent> expected = logger.getLoggedEvents();
    // action
    // construct similar FoV based detector
    // half width of 60 deg pointed along +Z in antenna frame
    // not a perfect small circle b/c FoV makes a polygon with great circles
    FieldOfView fov = new FieldOfView(Vector3D.PLUS_K, Vector3D.PLUS_I, pi / 3, 16, 0);
    // simple case for fixed pointing to be similar to elevation detector.
    // could define new frame with varying rotation for slewing antenna.
    GroundFieldOfViewDetector fovDetector = new GroundFieldOfViewDetector(topo, fov).withMaxCheck(5.0);
    Assert.assertSame(topo, fovDetector.getFrame());
    Assert.assertSame(fov, fovDetector.getFieldOfView());
    logger = new EventsLogger();
    prop = new KeplerianPropagator(orbit);
    prop.addEventDetector(logger.monitorDetector(fovDetector));
    prop.propagate(endDate);
    List<LoggedEvent> actual = logger.getLoggedEvents();
    // verify
    Assert.assertEquals(2, expected.size());
    Assert.assertEquals(2, actual.size());
    for (int i = 0; i < 2; i++) {
        AbsoluteDate expectedDate = expected.get(i).getState().getDate();
        AbsoluteDate actualDate = actual.get(i).getState().getDate();
        // same event times to within 1s.
        Assert.assertEquals(expectedDate.durationFrom(actualDate), 0.0, 1.0);
    }
}