[Orekit Users] TLEPropagator Question

[Thomas Neidhart <thomas.neidhart@spaceapplications.com>]

Dear all,

I am using this very nice library (many kudos also for making it
available as open-source!) to calculate visibility events for a
satellite based on TLEs.

For this purpose I have used the already available example using a
KeplerianPropagator and a custom ElevationDetector to collect the events.

This works so far, but I was a bit concerned about the accuracy of the
resulting events, especially when comparing it with some available
tracking sites on the internet (e.g. http://www.heavens-above.com/), as
results were diverging in the range of minutes after some hours.

If I understand it correctly, the provided KeplerianPropagator is a very
simplistic propagator based on a keplerian orbit, while the
TLEPropagator is way more sophisticated and should yield much more
accurate results. Sadly the TLEPropagator does not implement the
Propagator interface, but I created mysself a simple wrapper for testing
purposes (updating the SpacecraftState orbit with propagated P/V
coordinates from the TLEPropagator instead of propagating the orbit itself).

The results are very promising and are almost the same compared to other
sites (~ 1-2s delta). Can someone confirm that my assumptions so far are
correct wrt orbit propagation?

Best regards,

Thomas
-- 
Thomas Neidhart, Software Engineer
Space Applications Services, www.spaceapplications.com
Leuvensesteenweg 325, B-1932 Zaventem, Belgium
Phone: +32-(0)2-721.54.84, Fax: +32-(0)2-721.54.44