Re: [Orekit Developers] Status of the Android application -- 2

[Alexis ROBERT <alexis.robert@gmail.com>]

On Fri, Aug 12, 2011 at 4:21 PM, pascal parraud <pascal.parraud@c-s.fr> wrote:
>  - start date/end date are confusing to me. What this app does is to
> propagate one input orbit from an initial date(practically the input
> orbitdate)to some final date, where we want to retrieve the computed orbit
> parameters. As we consider an impulse maneuver, with no duration, start date
> and end date don't mean maneuver duration, the end date is really the final
> date for the propagation, but start date stands here for the maneuver time.
> In fact it would be much more suitable to be able to chose the kind of event
> which triggers the maneuver (among a predefined TBD list of meaningful ones
> such as apside, date...). Luc, what do you think of this ?

Yes exactly, that's what did the little J2SE app I made for testing.

About entering the different kind of events, I'm currently thinking on
how to do the "event detection" part of the program which should input
all kind of event types (if I understood correctly).

>  - by the way, the TLE format contains the orbit date (line 1 fields 7 & 8),
> so we must provide a way to optionnaly input or not some date(this holds
> also for the orbit conversion). In the first case, the propagate method must
> be called, as it is already done in your code.

Ah ok I didn't know, thanks :)

>  - the final orbit is shown in cartesian form ... and I guesssometimesit
> won't be the good one, so it will be fine to ask as an input for the choice
> of the output orbit format.

Currently all the output part is temporary and would be better
(without just using toString() methods everywhere). About conversion,
I was more thinking of a button which would send it to the orbit
conversion part, but your choice seems to be better.

> * about the code :
>  - in the ManeuverComputeActivity, even for the TLE you can get :
> orbit_frame = propagator.getFrame (line 167) as the TLE propagator is a full
> Propagator.

I did that before, and it resulted in a NullPointerException so I forced TEME.

> Thank you for this good job (and sorry for these little spec changes...)

No problem for the spec changes, it's normal :)

> Have a nice WE

Thanks, you too !

Alexis