Re: [Orekit Users] Mimic TLEPropagator with Numerical?

Hello Evan,

Thank you for your time. I never tried PropagatorConverter yet, but I cam across it earlier. I would give a try now. But it would be more helpful if I have an example or more likely a "PropagatorConverterTest" to avoid programming errors also I could get a rough idea about timeSpan and nbpoints. Is it possible that you can provide me a sample code?

Thank you again for your help.

Regards,

Justin

On Tue, Mar 28, 2017 at 4:12 PM, Ward, Evan <Evan.Ward@nrl.navy.mil> wrote:

Hi Justin,

Welcome to Orekit.On Tue, 2017-03-28 at 21:01 +0200, justin4leb@gmail.com wrote:
> Hello All,
>
> I am new in using OREKIT. I was wondering if its possible to mimic
> TLEPropagator by incorporating similar force models into a Numerical
> propagator. Basically, I am trying to replicate the results of the
> "Satellite
> Orbital Conjunction Reports Assessing Threatening Encounters in
> Space" (SOCRATES) that are given in the celestrak
> website :http://celestrak.com/cgi-bin/searchSOCRATES.pl?IDENT=NAME&NA
> ME_TEXT1=&NAME_TEXT2=&ORDER=MINRANGE&MAX=10
>
> I am able to get exact (very closer : +/-0.1 seconds) closest
> approach
> results, but not with a Numerical Propagator (with J2 perturbations).
> I am
> aware TLEprop is based on SGP4/SDP4 model but I wonder if it is
> possible to
> bring that model into Numerical. Because I would like to experiment
> by
> applying small delta-Vs to the state to increase the closest approach
> distance
> which cannot be done within a TLEPropagator.

Try taking a look at the propagation.conversion package, specifically
the PropagatorConverter and PropagatorBuilder. While you won't be able
to recover the exact initial condition used to create the TLE (TLE's
are a form of lossy compression) it should match to the accuracy of the
TLE theory. You'll probably need to experiment with the timeSpan and
nbPoints parameters to fit your use case.

Best Regards,

Evan