Re: [Orekit Users] gpstk vs OreKit

[MAISONOBE Luc <luc.maisonobe@c-s.fr>]

w.grossman@ieee.org a écrit :

Hi,


> The GPS Toolkit (gpstk) predates OreKit. gpstk is C/C++ and OreKit is java.
>
> Certainly the developers of OreKit are familiar with gps toolkit (gpstk).  I
> assume that the OreKit developers saw certain gpstk deficiencies upon which
> OreKit improves.  What are those deficiencies or, more generally, why would
> one use OreKit over gpstk.

Orekit started in 2002 and targeted operational space flight dynamics, i.e.
it was at that time more related to mission analysis, maneuvers preparation,
operational predictions than to navigation. The fact the scope was extended
and now includes navigation and science dates only from the last one or two
years, so most of what we used to build thes capabilities relies more on
what was already available in Orekit than on comparison with other tools.

We did not look specifically at gpstk and do not know about its deficiencies.

Also from a legal point of view, we cannot reuse or translate gpstk code.
This would be considered a modification or this initial code and as such
would need to be published under the LGPL licence and all code published
by Orekit project is under the Apache 2 License. To be clear, translating
code is *not* the same as calling pristine LGPL code in an application.
What we often do is go back to the algorithms from reference papers, thus
avoiding licensing issues.

GPSTK is specialized on navigation since years, whereas Orekit started
only recently. We are improving very fast, and adding up to date
models with a steady pace but are not yet at the same level. GPSTK
activity seems low (last commits 8 months ago) and community limited.
So if your needs are immediate and focused on navigation only, GPSTK is
probably a better choice. If you can wait for a few months for accurate
navigation or need a broader scope, you can rely on Orekit.

best regards,
Luc

> Thanks.