Re: [Orekit Developers] ESA SoCiS project: Create a web application for orbit propagation with operational forecasts

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

Ricardo Aguirre <el.mastin@gmail.com> a écrit :

> Hi
Hi Ricardo,

> my name is Ricardo Aguirre
> I study in Italy and I'm interested in your ESA SoCiS project "Create a web
> application for orbit propagation with operational forecasts".
> I have some questions for you:
>
> 1.- When you refer Apache Software license, do you mean  Apache License,
> Version 2.0?
Yes.

> 2.- If you say that entire development should be done in Java, then it will
> have problems to run over a tiny devices (mobile phone). Doesn't matters?
Many mobile phones now have Java available, and in fact previous  
projects have already proven a complete Orekit propagation runs quite  
well on a mobile phone. So this case should be even less demanding on  
the device.
Another point is that the mobile phone use case was only one example  
use case among others, we can also think of a desktop computer  
connecting to the service. If you look at the proposed splitting into  
work packages, we propose to do the project mainly on a desktop  
computer first.

> 3.- Maybe this question have no space here (because maybe SoCiS student
> should do this, during the program) but. Can you enlist all the direct
> method calls (used in the standalone application) that want to be
> distributed by the mentioned Messaging patterns?
You can find some example code for the three propagation modes here:  
<https://www.orekit.org/static/tutorial/propagation.html>.
The most important calls are:

 slave mode:
   the call to propagate(extrapDate) inside the time loop,
   which is a call from the client to the server

 master mode:
   the call to handleStep which is a callback from the server
   to the client, and during the processing the client calls
   methods getDate and getOrbit in this case, using the
   object provided by the server

 ephemeris mode:
   the call to propagate followed by the call to getGeneratedEphemeris

Of course, there are also all the initial setup calls which are less  
demanding.
The main differences to be expected in the three modes are the  
following. In slave mode, the client doest a lot of requests to the  
server, sending only a date and receiving only a spacecraft state. In  
master mode, it is mainly the server that has to somehow call the  
client back each time a new spacecraft state has been generated. In  
ephemeris mode, there are only a handful of calls, but huge amounts of  
data are transmitted when the ephemeris is transfered.

best regards,
Luc

> Regards
>
> --Panzón


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