Satellite Frame in the OnBoardAntennaRangeModifier class

Orekit usage
1

Hello Orekit Team,

I have a really simple question. How is the Satellite frame defined in the OnBoardAntennaRangeModifier class? I have an offset that is purely radial and I want to know how the handle it. I could’nt find informtion on the frame used…

Thank you very much,

Luca

2

Hi,

For the OnBoardAntennaRangeModifier class it depends on the attitude mode. Therefore, the offset must be consistent with the axis definition of the attitude mode.

For ground pointing laws, the definition is given in the code:

// attitude definition:
// line of sight    -> +z satellite axis,
// orbital velocity -> (z, +x) half plane

Therefore, for NadirPointing the satellite z axis is pointing to the vertical of the ground point under satellite.

Best regards,
Bryan

3

Ok Thank you, and is there a default attitude mode if no one is defined ?

4

Yes, it is an attitude provider aligned with the orbit frame: InertialProvider.java.

Bryan