I have embarked on a journey to perform Orbit Determination outside of the Earth’s Sphere of Influence.
In such a regime, we would need to consider the gravity of Earth, Moon, Sun, Jupiter, and an N number of bodies based on the use-case. An orbit in such a regime is generally non-Keplerian, non-planar, and not centered about a fixed barycenter (hinting to the inadecuacy of CR3BP limited realism for such a task in cislunar space, for example, to which @luc has eluded to here!.
BLSEstimator I use requires a
PropagatorBuilder. The underlying propagator that is built needs to have (inspired from the CR3BP tutorials):
numericalPropagator.setOrbitType(null), to clarify that the orbit is non-Keplerian
numericalPropagator.setIgnoreCentralAttraction(true), to clarify that there is no single central attraction point
numericalPropagator.addForceModel(...)with my choice of n-body accelerations from selected planetary bodies, similarly to @sebastien.herbiniere suggestion!
However, I do not have access to the first two methods from the
NumericalPropagatorBuilder object. I noticed that the builder, inside the
buildPropagator method, attempts to conditionally add a Newtonian attraction by itself from the input
mu, if one such force is not present.
Adding the solar bodies as perturbation force models in an Earth-Centered initial orbit is probably not equivalent to what I would like to achieve, but yet again I am not sure now!
Question: What recommendations would you have to perform Orbit Determination within an n-body attraction environment, for a non-Keplerian orbit with known initial state guess in Cartesian coordinates (say in J2000?) ? I feel that if
BatchLSEstimator had a
NumericalPropagator argument instead of
NumericalPropagatorBuilder, my problem would be solved, is that right or no? Alternatively, if the
buildPropagator and keep a reference of the result in its instance as a member, I would also be able to reference it and use the setters on-the-fly (sounds too sketchy perhaps?).
P.S. Can I just say how happy I am for Orekit 12.0?