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

The IEEE Life Fellow’s contributions opened the door for more advanced navigation systems

3 min read
James J. Spilker, Jr. at the 2015 IEEE Honors Ceremony, where he received the IEEE Edison Medal.
James J. Spilker, Jr. at the 2015 IEEE Honors Ceremony, where he received the IEEE Edison Medal.
Photo: IEEE

THE INSTITUTEIEEE 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 Professor Spilker’s passion and dedication to his work.

“I easily could have been homeless.” 

Professor 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 two-year community college, in Kentfield, Calif. 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. 

“It was a magical time.” 

Spilker’s career began at Lockheed Research Labs, in Palo Alto, Calif., 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, Calif., 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, Calif., 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 world-wide accuracy.

In 1982, Spilker was elevated to IEEE Fellow “for contributions to the development of digital satellite communications and navigation systems.”

“If you are going to finish, finish fast.”

Over the next 25 years, Spilker grew Stanford Telecommunications into a company of 1,300 employees that operated in five states.

After he sold the company in 1999 to a consortium of buyers, including Dii Group, now Alcatel; Intel; and ITT Industries, Spilker helped develop the L5 civilian signal. This technology, which was launched in 2011, provides higher accuracy and more resistance to the effects of interference on navigation, such as from space weather. 

Spilker also co-invented the split spectrum mode, now called binary offset carrier, for modern GPS ranging. This technology allows civilian and military signals to use separate areas of the spectrum. He also developed adaptive vector tracking for simultaneously tracking ranging signals from multiple satellites. This will be critical to handling GPS satellite navigation expansion as new satellites and signals are introduced by space agencies around the world.

Spilker joined Stanford in 2001 as a consulting professor of electrical engineering and aeronautical and astronautical engineering.

His highly cited book “Global Positioning System: Theory and Applications” is considered the standard reference for GPS and it won the 1996 American Institute of Aeronautics and Astronautics Sommerfield Book Award. His popular textbook, “Digital Communications by Satellite,” went through 10 reprints.

 “I didn’t have to work, this was my hobby.” 

Professor Spilker received an impressive number of awards throughout his life for his pioneering work and innovations.

He was the recipient of the 2015 IEEE Edison Medal “for contributions to the development and implementation of the GPS civilian navigation system and a career of meritorious achievement.”

Professor Spilker was also awarded the 1987 Arthur Young Entrepreneur of the Year Award, the 1999 Institute of Navigation Kepler Award, the 2000 U.S. Air Force Space Command Recognition Award, and the 2002 Institute of Navigation Burka Award.

Earlier this year, he, along with Hugo Freuhauf, Brad Parkinson and Richard Schwartz, were honored with the 2019 Queen Elizabeth Prize for Engineering for their collective work on GPS.

Professor Spilker’s key contributions to the development—and subsequent enhancement—of GPS, have a profound impact on more than 4 billion people using the technology around the world. Today, each of us benefits from his efforts and the myriad applications stemming from his work are intricately woven into the fabric of everyone’s daily lives. From mobile phones and commercial and private aviation to agriculture and disaster warning and recovery systems—all rely on GPS.

IEEE and its philanthropic partner, the IEEE Foundation, relished their relationship with Professor Spilker and his wife Anna Marie.

“We will continue to honor his legacy through promoting his entrepreneurial spirit, facilitating the education of future engineers, and preserving his unparalleled contributions to technology, which betters lives daily,” IEEE Foundation President John Treichler says. 

Spilker is survived by his wife, Anna Marie Spilker; two sisters; four children; 12 grandchildren; three great-grandchildren; as well as Merry, his German Shepherd, and two rescue cats, Siam and Tiger.

Natalie Krauser is the development officer for the IEEE Foundation.

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