High-res, low-latency RTLS / Realtime GPS Positioning

[FingerFlinger]

Anybody have experience with this? Under certain conditions, I know that it's possible to achieve real-time accuracy of a few centimeters using GPS, but I imagine that the lag would be unacceptable for VR purposes.

Radio signal strength triangulation seems out; we explored this a little when I did my senior design project in school, and it's just too difficult right now.

And then there's optical, which I think brantlew has started playing with, and I will begin exploring as well.

I want to start experimenting with area-constrained level design; using tricks and layouts that make the player experience a large virtual world while actually constraining them to say, a tennis court. I think it has huge potential for VR accessibility, but we need to develop a vocabulary of techniques and tricks to actually make it work. So, when the weather gets nice this summer, I'd like to make some simple demos in Unity and perform some experiments.