Some of the Cisco Meraki technologies look really interesting. I am especially interested in what they refer to as anayltics, but I would class as tracking.

Essentially the wifi hotspots listen for probe requests directed to themselves, or other access points, calculate the RSSI of the client and use this to I assume trilaterate there location with other access points. This allows the network admin to see physically where devices are as they roam around the premises.

I was wondering if there was any open source alternative to this. For example can airbase-ng be configured to do this? Or are there any competing commercial options for this? I know some retail outlets do similar things with Bluetooth devices.

See this video for example: https://www.youtube.com/watch?v=DRXqNnit8bU