Professor Enge designs navigation systems that are safe and secure. These navigation systems must detect feared events that threaten to introduce hazardous position errors. These days, such navigation systems are usually based on the Global Positioning System (GPS) with substantive toughening and augmentation. He has worked on such systems for maritime and air applications, and two of these navigation systems have been deployed worldwide. Applications of current interest include the landing of airplanes and un-piloted air systems (UAS). He received his B.S.E.E. from the University of Massachusetts, and his M.S.E.E. and PhD from the University of Illinois. Today, he is the Vance and Arlene Coffman Professor of Engineering at Stanford University, where he directs the Stanford Center for Position Navigation and Time.