I agree although presumably when you add more devices and types of signal you can build a much richer picture without 3 access points.
For example, in my living room I have a cordless landline, Bluetooth soundbar speaker, WiFi access point, a fixed media box that uses WiFi. Presumably you could build a picture from the interference patterns of these different types of device, which are all on similar frequencies (2.4GHz ish).
I agree although presumably when you add more devices and types of signal you can build a much richer picture without 3 access points.
For example, in my living room I have a cordless landline, Bluetooth soundbar speaker, WiFi access point, a fixed media box that uses WiFi. Presumably you could build a picture from the interference patterns of these different types of device, which are all on similar frequencies (2.4GHz ish).
Research from a few years ago was able to measure gait (so a person’s height and build etc) from the wifi shadow of a single router.
I assume 3 is to get the super accurate placement.