@Test
public void testExceedHistoryBackward() throws OrekitException, IOException {
final double period = 900.0;
// the raw detector should trigger one event at each 900s period
final DateDetector raw =
new DateDetector(orbit.getDate().shiftedBy(+0.5 * period))
.withMaxCheck(period / 3)
.withHandler(new ContinueOnEvent<DateDetector>());
for (int i = 0; i < 300; ++i) {
raw.addEventDate(orbit.getDate().shiftedBy(-(i + 0.5) * period));
}
// in fact, we will filter out half of these events, so we get only one event every 2 periods
final EventEnablingPredicateFilter<DateDetector> filtered =
new EventEnablingPredicateFilter<DateDetector>(
raw,
new EnablingPredicate<DateDetector>() {
public boolean eventIsEnabled(
SpacecraftState state, DateDetector eventDetector, double g) {
double nbPeriod = orbit.getDate().durationFrom(state.getDate()) / period;
return ((int) FastMath.floor(nbPeriod)) % 2 == 1;
}
});
Propagator propagator = new KeplerianPropagator(orbit);
EventsLogger logger = new EventsLogger();
propagator.addEventDetector(logger.monitorDetector(filtered));
propagator.propagate(orbit.getDate().shiftedBy(-301 * period));
List<LoggedEvent> events = logger.getLoggedEvents();
// 300 periods, 150 events as half of them are filtered out
Assert.assertEquals(150, events.size());
// as we have encountered a lot of enabling status changes, we exceeded the internal history
// if we try to display again the filtered g function for dates far in the future,
// we will not see the zero crossings anymore, they have been lost
propagator.clearEventsDetectors();
for (double dt = -5000.0; dt > -10000.0; dt -= 3.0) {
double filteredG = filtered.g(propagator.propagate(orbit.getDate().shiftedBy(dt)));
Assert.assertTrue(filteredG < 0.0);
}
// on the other hand, if we try to display again the filtered g function for future dates
// that are still inside the history, we still see the zero crossings
for (double dt = -195400.0; dt > -196200.0; dt -= 3.0) {
double filteredG = filtered.g(propagator.propagate(orbit.getDate().shiftedBy(dt)));
if (dt < -195750) {
Assert.assertTrue(filteredG < 0.0);
} else {
Assert.assertTrue(filteredG > 0.0);
}
}
}
private void doElevationTest(
final double minElevation,
final AbsoluteDate start,
final AbsoluteDate end,
final int expectedEvents,
final boolean sameSign)
throws OrekitException {
final ElevationExtremumDetector raw =
new ElevationExtremumDetector(0.001, 1.e-6, new TopocentricFrame(earth, gp, "test"))
.withHandler(new ContinueOnEvent<ElevationExtremumDetector>());
final EventEnablingPredicateFilter<ElevationExtremumDetector> aboveGroundElevationDetector =
new EventEnablingPredicateFilter<ElevationExtremumDetector>(
raw,
new EnablingPredicate<ElevationExtremumDetector>() {
public boolean eventIsEnabled(
final SpacecraftState state,
final ElevationExtremumDetector eventDetector,
final double g)
throws OrekitException {
return eventDetector.getElevation(state) > minElevation;
}
})
.withMaxCheck(60.0);
Assert.assertEquals(0.001, raw.getMaxCheckInterval(), 1.0e-15);
Assert.assertEquals(60.0, aboveGroundElevationDetector.getMaxCheckInterval(), 1.0e-15);
Assert.assertEquals(1.0e-6, aboveGroundElevationDetector.getThreshold(), 1.0e-15);
Assert.assertEquals(
AbstractDetector.DEFAULT_MAX_ITER, aboveGroundElevationDetector.getMaxIterationCount());
Propagator propagator =
new EcksteinHechlerPropagator(
orbit,
Constants.EIGEN5C_EARTH_EQUATORIAL_RADIUS,
Constants.EIGEN5C_EARTH_MU,
Constants.EIGEN5C_EARTH_C20,
Constants.EIGEN5C_EARTH_C30,
Constants.EIGEN5C_EARTH_C40,
Constants.EIGEN5C_EARTH_C50,
Constants.EIGEN5C_EARTH_C60);
EventsLogger logger = new EventsLogger();
propagator.addEventDetector(logger.monitorDetector(aboveGroundElevationDetector));
propagator.propagate(start, end);
for (LoggedEvent e : logger.getLoggedEvents()) {
final double eMinus = raw.getElevation(e.getState().shiftedBy(-10.0));
final double e0 = raw.getElevation(e.getState());
final double ePlus = raw.getElevation(e.getState().shiftedBy(+10.0));
Assert.assertTrue(e0 > eMinus);
Assert.assertTrue(e0 > ePlus);
Assert.assertTrue(e0 > minElevation);
}
Assert.assertEquals(expectedEvents, logger.getLoggedEvents().size());
propagator.clearEventsDetectors();
double g1Raw = raw.g(propagator.propagate(orbit.getDate().shiftedBy(18540.0)));
double g2Raw = raw.g(propagator.propagate(orbit.getDate().shiftedBy(18624.0)));
double g1 =
aboveGroundElevationDetector.g(propagator.propagate(orbit.getDate().shiftedBy(18540.0)));
double g2 =
aboveGroundElevationDetector.g(propagator.propagate(orbit.getDate().shiftedBy(18624.0)));
Assert.assertTrue(g1Raw > 0);
Assert.assertTrue(g2Raw < 0);
if (sameSign) {
Assert.assertTrue(g1 > 0);
Assert.assertTrue(g2 < 0);
} else {
Assert.assertTrue(g1 < 0);
Assert.assertTrue(g2 > 0);
}
}
