@Test
public void testLineIntersection() throws OrekitException {
AbsoluteDate date = AbsoluteDate.J2000_EPOCH;
Frame frame = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
OneAxisEllipsoid model = new OneAxisEllipsoid(100.0, 0.9, frame);
Vector3D point = new Vector3D(0.0, 93.7139699, 3.5930796);
Vector3D direction = new Vector3D(0.0, 1.0, 1.0);
Line line = new Line(point, point.add(direction), 1.0e-10);
GeodeticPoint gp = model.getIntersectionPoint(line, point, frame, date);
Assert.assertEquals(gp.getAltitude(), 0.0, 1.0e-12);
Assert.assertTrue(line.contains(model.transform(gp)));
model = new OneAxisEllipsoid(100.0, 0.9, frame);
point = new Vector3D(0.0, -93.7139699, -3.5930796);
direction = new Vector3D(0.0, -1.0, -1.0);
line = new Line(point, point.add(direction), 1.0e-10).revert();
gp = model.getIntersectionPoint(line, point, frame, date);
Assert.assertTrue(line.contains(model.transform(gp)));
model = new OneAxisEllipsoid(100.0, 0.9, frame);
point = new Vector3D(0.0, -93.7139699, 3.5930796);
direction = new Vector3D(0.0, -1.0, 1.0);
line = new Line(point, point.add(direction), 1.0e-10);
gp = model.getIntersectionPoint(line, point, frame, date);
Assert.assertTrue(line.contains(model.transform(gp)));
model = new OneAxisEllipsoid(100.0, 0.9, frame);
point = new Vector3D(-93.7139699, 0.0, 3.5930796);
direction = new Vector3D(-1.0, 0.0, 1.0);
line = new Line(point, point.add(direction), 1.0e-10);
gp = model.getIntersectionPoint(line, point, frame, date);
Assert.assertTrue(line.contains(model.transform(gp)));
Assert.assertFalse(line.contains(new Vector3D(0, 0, 7000000)));
point = new Vector3D(0.0, 0.0, 110);
direction = new Vector3D(0.0, 0.0, 1.0);
line = new Line(point, point.add(direction), 1.0e-10);
gp = model.getIntersectionPoint(line, point, frame, date);
Assert.assertEquals(gp.getLatitude(), FastMath.PI / 2, 1.0e-12);
point = new Vector3D(0.0, 110, 0);
direction = new Vector3D(0.0, 1.0, 0.0);
line = new Line(point, point.add(direction), 1.0e-10);
gp = model.getIntersectionPoint(line, point, frame, date);
Assert.assertEquals(gp.getLatitude(), 0, 1.0e-12);
}
@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);
}
