I think that's a differential GPS antenna. The metallic "upside down" mixing bowls are deflectors which absorb multi-path interference from surrounding buildings and structures. Just guessing though.
My guess, some sort of lightning detector. I doubt it is a GPS. I have a hand held GPS unit that I use for golf, made by SkyCaddie. It gets its signal from satellites. There are other GPS units made by other companies.
I simply turn mine on, go to the course listings, select my course and it does the rest. Tells me the yardages to the front, middle and back of the greens. Tells me the yardages to the hazards, bunkers etc and what the yardage is to carry them.
I have an older model, pretty basic. The new models show the fairways etc in a fly by mode. Pretty neat toys, very helpful. It is like having a caddie!
We have a lightning detector at my course. but I have never see the antenna. I don't think there is an outside antenna on that unit.
Hey maybe that thing is a high tech bug zapper!