Sounds like they used a tri-static Doppler radar technique. A conventional radar was used for the transmitter, and two separate dishes (GBT in WV, and Goldstone in CA) were used as receiving stations.
4 posted on 03/10/2017 6:47:11 AM PST by backwoods-engineer
(Trump won; I celebrated; I'm good. Let's get on with the civil war now.)