I was thinking of component cost when I said a few dollars; of course a commercial product is going to sell for thousands. In the 60GHz band (IEEE 802.11ad), y

I was thinking of component cost when I said a few dollars; of course a commercial product is going to sell for thousands. In the 60GHz band (IEEE 802.11ad), you can plausibly get down to ~.5cm resolution with cheap, COTS network gear.