Locate RFID tag using iPhone

I am looking into building an app (on my laptop to start) that would be able to locate the signal emitted by an RFID tag (non passive). Say I attach this to my key ring, what would be required of the application to triangulate the location of the开发者_运维知识库 RFID tag in a 10m range. Would this even be possible using this technology? I see some older posts here so wondering if there have been any tech breakthroughs in this area since then?

Dan

---

As jasoncrawford commented, to do this with iPhone you need to make your own hardware accessory first.

As for triangulating RFID tags, this might help: http://portal.acm.org/citation.cfm?doid=1198555.1198717