First - let me apologize for how little I understand on this subject. Please throw knowledge, not flames.
I know that you can get some rough location information from a wireless device by comparing the relative signal strengths of multiple access points (assuming you have set up a signal strength map for your facility). What I'm looking for is the inverse of that where all of the custom programming is on the server as opposed to having signal detection software running in the portable device.
I have a large facility. Can I set up multiple access points in my facility such that my portable device remains connected as I walk around (yes ... I'm not sure of the details but I am sure you can do this) AND have software running on my server that tracks what devices are connected to the access points and the relative signal strength of that portable device across multiple access points.
This would be a passive tracker based strictly on the server, rather than having signal reporting software on the portable devices.