Bradford Parkinson is chief architect of the now-ubiquitous Global Positioning System (GPS), which he led as a U.S. Air Force colonel in 1973. As a professor at Stanford, he pioneered GPS for aviation and other applications, including the Wide Area Augmentation System (WAAS) used by the FAA. More recently, he led the NASA/Stanford Gravity Probe B program that validated Einstein's General Theory of Relativity to an unprecedented accuracy. Parkinson is co-editor and an author of the best-selling textbook, Global Positioning System: Theory and Applications. He received his PhD from Stanford in 1966 and is a Stanford Engineering Professor Emeritus of Aeronautics and Astronomics.