>>356458808
Go read the patents. It's going to be Lighthouse 3.0 with no moving parts. The IR sensors will have polarizers on them to make them direction sensitive, be able to reject scattered (ie: reflected off your shiny dragon dildo) light, and most likely every device will have both sensors and emitters to enable them to all track each other. Lighthouses will probably be nothing more than an omnidirectional IR light, if you choose to use them. They might be able to retain some backwards compatibility with Lighthouse 2.0 tracking if they implement things right.
Why do inside out with IR lights and sensors instead of cameras? Much less processing overhead, much less power use, possibly backwards compatibility with older SteamVR gear.