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[Orekit Developers] From osculating parameters to mean parameters for LEO orbits



Hi to all,
 
Thanks for the use of the great Orekit tool !
My question is about the computation of mean parameters from a LEO osculating orbit.
In order to get some operational parameters, I need to compute the mean parameters at each steps of the global propagation.
One way is to use the OsculatingToMeanElementsConverter with a specific propagator.
I tried with a classical EcksteinHechlerPropagator, however the following exception has been raised :
 
Exception in thread "main" org.orekit.errors.PropagationException: impossible de calculer les paramètres moyens au sens de Eckstein-Hechler après 101 itérations
        at org.orekit.propagation.analytical.EcksteinHechlerPropagator.<init>(EcksteinHechlerPropagator.java:318)
        at org.orekit.propagation.analytical.EcksteinHechlerPropagator.<init>(EcksteinHechlerPropagator.java:200)
        at main.Init.main(Init.java:91)
Caused by: org.orekit.errors.PropagationException: impossible de calculer les paramètres moyens au sens de Eckstein-Hechler après 101 itérations
        at org.orekit.propagation.analytical.EcksteinHechlerPropagator.computeMeanParameters(EcksteinHechlerPropagator.java:394)
        at org.orekit.propagation.analytical.EcksteinHechlerPropagator.resetInitialState(EcksteinHechlerPropagator.java:327)
        at org.orekit.propagation.analytical.EcksteinHechlerPropagator.<init>(EcksteinHechlerPropagator.java:311)
        ... 2 more
 
Indeed, when calling the EcksteinHechlerPropagator constructor, it takes more than 100 iterations to compute mean parameters at the initial state, and therefore the exception is raised.
Here is a specific orbit among others, retrieved from the simulation, for which the computation in mean elements is not possible :
 
AbsoluteDate t = new AbsoluteDate(2016, 07, 22, 9, 35, 42.562, TimeScalesFactory.getUTC());
Frame frame = FramesFactory.getEME2000();
Orbit orbit = new EquinoctialOrbit(7075842.806163763, 0.0012957331188810572, -4.760791390305797E-4, 0.14011350699555794, -1.1457596828634813, 79339.41232985309, PositionAngle.TRUE, frame, t, Constants.WGS84_EARTH_MU);
Double mass = 436.5;
double c20 = Constants.EIGEN5C_EARTH_C20;
double c30 = Constants.EIGEN5C_EARTH_C30;
double c40 = Constants.EIGEN5C_EARTH_C40;
double c50 = Constants.EIGEN5C_EARTH_C50;
double c60 =  Constants.EIGEN5C_EARTH_C60;
EcksteinHechlerPropagator analyticalPropagatorWrong = new EcksteinHechlerPropagator(orbit, mass, Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_MU, c20, c30, c40, c50, c60);
 
 
Is there a better way to convert osculating parameters to mean parameters?
Best,
 
Lara Hué
 
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