U.S. Air Force Airmen assigned to the 633rd Security Forces Squadron train with Sgt. Pelham Felder, Hampton Police Division Homeland Security unit supervisor, on basic radar operation at Langley Air Force Base, Va., Oct. 15, 2015. During training, Airmen learned about the Doppler Theory and principles, how to set up and test radars and how to visually estimate the speed of a vehicle. (U.S. Air Force photo by Senior Airman Kayla Newman/Released)