radarman, it surely would not be sensible for a ground facility to employ different callsigns on the same frequency, according to the service being provided ...
In the circumstances you describe, I would have thought you should call yourself
"XXX Radar", as that would indicate capabilities for the other two services (i.e. procedural approach & flight information) that you may be called upon to provide.
If you announce yourself as
"XXX Approach", that would normally suggest to me that you were an Approach facility, and probably not equipped to provide a radar-based service.
"XXX Information" would clearly not be able to provide either of the other two services.
JD
