It is actually possible with the current ROS, We got our own solution based on Mikrotik APs.
However it requires extra development and servers to aggregate data and compute the position of devices, it's not a one-day task..
WiFi Positioning System is good idea for position detection of wireless stations in airport, hospital and etc. In that cases, Detection of accumulation of people in different locations can be effect for service management and place safety.
Hi! I'm interested. Do you have info? We are unable of having a true stream of all the data needed outside the APs...without stopping the wifi service or start/stop sniffer, for example.