@Test
public void testCartesian() throws OrekitException {
// Propagation of the initial at t + dt
final double dt = 3200;
propagator.setOrbitType(OrbitType.CARTESIAN);
final PVCoordinates finalState =
propagator.propagate(initDate.shiftedBy(dt)).getPVCoordinates();
final Vector3D pFin = finalState.getPosition();
final Vector3D vFin = finalState.getVelocity();
// Check results
final PVCoordinates reference = initialState.shiftedBy(dt).getPVCoordinates();
final Vector3D pRef = reference.getPosition();
final Vector3D vRef = reference.getVelocity();
Assert.assertEquals(0, pRef.subtract(pFin).getNorm(), 2e-4);
Assert.assertEquals(0, vRef.subtract(vFin).getNorm(), 7e-8);
try {
propagator.getGeneratedEphemeris();
Assert.fail("an exception should have been thrown");
} catch (IllegalStateException ise) {
// expected
}
}
@Test
public void testZeroInclination() throws OrekitException {
TLE tle =
new TLE(
"1 26451U 00043A 10130.13784012 -.00000276 00000-0 10000-3 0 3866",
"2 26451 000.0000 266.1044 0001893 160.7642 152.5985 01.00271160 35865");
TLEPropagator propagator = TLEPropagator.selectExtrapolator(tle);
PVCoordinates pv = propagator.propagate(tle.getDate().shiftedBy(100)).getPVCoordinates();
Assert.assertEquals(42171546.979560345, pv.getPosition().getNorm(), 1.0e-3);
Assert.assertEquals(3074.1890089357994, pv.getVelocity().getNorm(), 1.0e-6);
}
@Test
public void testSatCodeCompliance() throws IOException, OrekitException, ParseException {
BufferedReader rEntry = null;
BufferedReader rResults = null;
InputStream inEntry =
TLETest.class.getResourceAsStream("/tle/extrapolationTest-data/SatCode-entry");
rEntry = new BufferedReader(new InputStreamReader(inEntry));
try {
InputStream inResults =
TLETest.class.getResourceAsStream("/tle/extrapolationTest-data/SatCode-results");
rResults = new BufferedReader(new InputStreamReader(inResults));
try {
double cumulated = 0; // sum of all differences between test cases and OREKIT results
boolean stop = false;
String rline = rResults.readLine();
while (!stop) {
if (rline == null) break;
String[] title = rline.split(" ");
if (title[0].matches("r")) {
String eline;
int count = 0;
String[] header = new String[4];
for (eline = rEntry.readLine();
(eline != null) && (eline.charAt(0) == '#');
eline = rEntry.readLine()) {
header[count++] = eline;
}
String line1 = eline;
String line2 = rEntry.readLine();
Assert.assertTrue(TLE.isFormatOK(line1, line2));
TLE tle = new TLE(line1, line2);
int satNum = Integer.parseInt(title[1]);
Assert.assertTrue(satNum == tle.getSatelliteNumber());
TLEPropagator ex = TLEPropagator.selectExtrapolator(tle);
for (rline = rResults.readLine();
(rline != null) && (rline.charAt(0) != 'r');
rline = rResults.readLine()) {
String[] data = rline.split(" ");
double minFromStart = Double.parseDouble(data[0]);
double pX = 1000 * Double.parseDouble(data[1]);
double pY = 1000 * Double.parseDouble(data[2]);
double pZ = 1000 * Double.parseDouble(data[3]);
double vX = 1000 * Double.parseDouble(data[4]);
double vY = 1000 * Double.parseDouble(data[5]);
double vZ = 1000 * Double.parseDouble(data[6]);
Vector3D testPos = new Vector3D(pX, pY, pZ);
Vector3D testVel = new Vector3D(vX, vY, vZ);
AbsoluteDate date = tle.getDate().shiftedBy(minFromStart * 60);
PVCoordinates results = ex.getPVCoordinates(date);
double normDifPos = testPos.subtract(results.getPosition()).getNorm();
double normDifVel = testVel.subtract(results.getVelocity()).getNorm();
cumulated += normDifPos;
Assert.assertEquals(0, normDifPos, 2e-3);
;
Assert.assertEquals(0, normDifVel, 1e-5);
}
}
}
Assert.assertEquals(0, cumulated, 0.026);
} finally {
if (rResults != null) {
rResults.close();
}
}
} finally {
if (rEntry != null) {
rEntry.close();
}
}
}
@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);
}
@Test
public void testPropagationTypesHyperbolic() throws OrekitException, ParseException, IOException {
SpacecraftState state =
new SpacecraftState(
new KeplerianOrbit(
-10000000.0,
2.5,
0.3,
0,
0,
0.0,
PositionAngle.TRUE,
FramesFactory.getEME2000(),
initDate,
mu));
ForceModel gravityField =
new HolmesFeatherstoneAttractionModel(
FramesFactory.getITRF(IERSConventions.IERS_2010, true),
GravityFieldFactory.getNormalizedProvider(5, 5));
propagator.addForceModel(gravityField);
// Propagation of the initial at t + dt
final PVCoordinates pv = state.getPVCoordinates();
final double dP = 0.001;
final double dV =
state.getMu() * dP / (pv.getPosition().getNormSq() * pv.getVelocity().getNorm());
final PVCoordinates pvcM = propagateInType(state, dP, OrbitType.CARTESIAN, PositionAngle.MEAN);
final PVCoordinates pvkM = propagateInType(state, dP, OrbitType.KEPLERIAN, PositionAngle.MEAN);
final PVCoordinates pvcE =
propagateInType(state, dP, OrbitType.CARTESIAN, PositionAngle.ECCENTRIC);
final PVCoordinates pvkE =
propagateInType(state, dP, OrbitType.KEPLERIAN, PositionAngle.ECCENTRIC);
final PVCoordinates pvcT = propagateInType(state, dP, OrbitType.CARTESIAN, PositionAngle.TRUE);
final PVCoordinates pvkT = propagateInType(state, dP, OrbitType.KEPLERIAN, PositionAngle.TRUE);
Assert.assertEquals(0, pvcM.getPosition().subtract(pvkT.getPosition()).getNorm() / dP, 0.3);
Assert.assertEquals(0, pvcM.getVelocity().subtract(pvkT.getVelocity()).getNorm() / dV, 0.4);
Assert.assertEquals(0, pvkM.getPosition().subtract(pvkT.getPosition()).getNorm() / dP, 0.2);
Assert.assertEquals(0, pvkM.getVelocity().subtract(pvkT.getVelocity()).getNorm() / dV, 0.3);
Assert.assertEquals(0, pvcE.getPosition().subtract(pvkT.getPosition()).getNorm() / dP, 0.3);
Assert.assertEquals(0, pvcE.getVelocity().subtract(pvkT.getVelocity()).getNorm() / dV, 0.4);
Assert.assertEquals(0, pvkE.getPosition().subtract(pvkT.getPosition()).getNorm() / dP, 0.009);
Assert.assertEquals(0, pvkE.getVelocity().subtract(pvkT.getVelocity()).getNorm() / dV, 0.006);
Assert.assertEquals(0, pvcT.getPosition().subtract(pvkT.getPosition()).getNorm() / dP, 0.3);
Assert.assertEquals(0, pvcT.getVelocity().subtract(pvkT.getVelocity()).getNorm() / dV, 0.4);
}
@Test
public void testPropagationTypesElliptical() throws OrekitException, ParseException, IOException {
ForceModel gravityField =
new HolmesFeatherstoneAttractionModel(
FramesFactory.getITRF(IERSConventions.IERS_2010, true),
GravityFieldFactory.getNormalizedProvider(5, 5));
propagator.addForceModel(gravityField);
// Propagation of the initial at t + dt
final PVCoordinates pv = initialState.getPVCoordinates();
final double dP = 0.001;
final double dV =
initialState.getMu() * dP / (pv.getPosition().getNormSq() * pv.getVelocity().getNorm());
final PVCoordinates pvcM =
propagateInType(initialState, dP, OrbitType.CARTESIAN, PositionAngle.MEAN);
final PVCoordinates pviM =
propagateInType(initialState, dP, OrbitType.CIRCULAR, PositionAngle.MEAN);
final PVCoordinates pveM =
propagateInType(initialState, dP, OrbitType.EQUINOCTIAL, PositionAngle.MEAN);
final PVCoordinates pvkM =
propagateInType(initialState, dP, OrbitType.KEPLERIAN, PositionAngle.MEAN);
final PVCoordinates pvcE =
propagateInType(initialState, dP, OrbitType.CARTESIAN, PositionAngle.ECCENTRIC);
final PVCoordinates pviE =
propagateInType(initialState, dP, OrbitType.CIRCULAR, PositionAngle.ECCENTRIC);
final PVCoordinates pveE =
propagateInType(initialState, dP, OrbitType.EQUINOCTIAL, PositionAngle.ECCENTRIC);
final PVCoordinates pvkE =
propagateInType(initialState, dP, OrbitType.KEPLERIAN, PositionAngle.ECCENTRIC);
final PVCoordinates pvcT =
propagateInType(initialState, dP, OrbitType.CARTESIAN, PositionAngle.TRUE);
final PVCoordinates pviT =
propagateInType(initialState, dP, OrbitType.CIRCULAR, PositionAngle.TRUE);
final PVCoordinates pveT =
propagateInType(initialState, dP, OrbitType.EQUINOCTIAL, PositionAngle.TRUE);
final PVCoordinates pvkT =
propagateInType(initialState, dP, OrbitType.KEPLERIAN, PositionAngle.TRUE);
Assert.assertEquals(0, pvcM.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 3.0);
Assert.assertEquals(0, pvcM.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 2.0);
Assert.assertEquals(0, pviM.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 0.6);
Assert.assertEquals(0, pviM.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 0.4);
Assert.assertEquals(0, pvkM.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 0.5);
Assert.assertEquals(0, pvkM.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 0.3);
Assert.assertEquals(0, pveM.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 0.2);
Assert.assertEquals(0, pveM.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 0.2);
Assert.assertEquals(0, pvcE.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 3.0);
Assert.assertEquals(0, pvcE.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 2.0);
Assert.assertEquals(0, pviE.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 0.03);
Assert.assertEquals(0, pviE.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 0.04);
Assert.assertEquals(0, pvkE.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 0.4);
Assert.assertEquals(0, pvkE.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 0.3);
Assert.assertEquals(0, pveE.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 0.2);
Assert.assertEquals(0, pveE.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 0.07);
Assert.assertEquals(0, pvcT.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 3.0);
Assert.assertEquals(0, pvcT.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 2.0);
Assert.assertEquals(0, pviT.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 0.3);
Assert.assertEquals(0, pviT.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 0.2);
Assert.assertEquals(0, pvkT.getPosition().subtract(pveT.getPosition()).getNorm() / dP, 0.4);
Assert.assertEquals(0, pvkT.getVelocity().subtract(pveT.getVelocity()).getNorm() / dV, 0.2);
}