Remembering James Spilker, Jr., Stanford Professor and Pioneer of GPS Technology

IEEE Life Fellow James J. Spilker, Jr., Global Positioning Systems (GPS) pioneer, philanthropist, and entrepreneur died on 24 September at the age of 86. Lives around the world are better every day thanks to Prof. Spilker’s passion and dedication to his work. Prof. Spilker’s early childhood was marked by difficulties. He was raised solely by his mother, battled illnesses, and, as he noted in the IEEE Oral History recorded, became legally blind in one eye when he was young. But, adversity did not hinder Spilker’s passion for learning, which continued throughout his life. Concerned that his mother could not afford tuition at a four-year college, he enrolled in the College of Marin, a twoyear community college, in Kentfield, California. His excellent performance, coupled with support from his teachers, led him to apply for a scholarship to Stanford. He passed the required entrance exam and had a perfect score in mathematics. In just five years, Spilker earned a bachelor’s degree, a master’s degree, and a Ph.D. in electrical engineering from the university.

 

Spilker’s career began at Lockheed Research Labs, in Palo Alto, California, where he invented a variant of the well-known phase-locked loop called the delay-locked loop (DLL), as described in a 1961 paper in the Proceedings of the IEEE. Variants of the DLL are still widely used in GPS receivers. He then joined Ford Aerospace, in Newport Beach, California, where he was the payload team leader for the first U.S. military communication satellites. He later led the Ford Aerospace Air Force 621B satellite navigation program, the predecessor to GPS. In 1973, Spilker cofounded Stanford Telecommunications in Santa Clara County, California, with two colleagues from Ford Aerospace. When the company received the contract to design the signals for GPS, Spilker and GPS became intricately linked. He was the key architect of the unique GPS signal structure, and his company developed the global monitoring equipment that has enabled unprecedented worldwide accuracy.