Re: [Orekit Users] Technical problem to use the class CircularFieldOfView

[Luc Maisonobe <Luc.Maisonobe@c-s.fr>]

Le 04/08/2011 16:51, cedric.goulard@cassidian.com a écrit :
> Hello Luc, 
> First,	I would like to thank you about your answers. It was fast!!!

You're welcome.

> 
> I have understood correctly the relation between the elevation threshold and
> the half aperture of the fov. However, I would like to know how you have define
> your instance of the CircularFieldOfViewDetector in your tests. Did you use a
> nadir attitude and define a fov center vector as Vector3D.PLUS_K ?

Look at the attached file.

> Can you provide the demonstration?

Yes, but not immediately. I have only a paper copy of a demonstration I
set up for students a few years ago and seem to have lost the TeX
source. I'll have to recreate it :-(

> 
> More, you said that "a circular field of view detector does not consider Earth
> masking". In fact, I want to take account of this aspect. How can I do to
> consider the Earth masking into a circular field of view detector.

You would have to define a custom detector for Earth limb, as this there
are no such detectors available in the library yet (we may add it later
on). Once you have this additional detector, you should combine it with
the fieldofview detector to build a sort of "logical and" between them,
at g function level. This is possible for events that do represent zone
entries and exit (like fields of view, limb, eclipse, maneuvers ...) but
not with other events (like target dates).

If you want, we provide training for Orekit (and Apache Commons Math
too), and building custom detectors as well as combining them is part of
the training program. If you want to attend a training session, please
send me a private message.

best regards,
Luc

> 
> Best regard
> Cedric
>