Enge, a professor of aeronautics and astronautics, was best known for his work on GPS. He led deployment of two navigation systems in use today. The first began operation in 1995 and had over 1.5 million marine and land users as of 2014. The second system launched in 2003 and was, at last count, in use in over 100,000 aircraft and by more than 1 million land users. In another notable example, Enge led the team that designed a system that allowed planes to land themselves entirely unaided by human hands, even on the pitching decks of aircraft carriers at sea – in the dark.
Leader of GPS advances
In 2004, Enge wrote an article in the popular magazine Scientific American about a “retooling” of the GPS system then underway that would make GPS accurate to a metre, a five- to tenfold improvement over existing capabilities. The article predicted that GPS was about to take off, quite literally, and presaged the ubiquity of GPS in everyday life.
“Geolocation coverage will extend from hiking trails and sea-lanes all the way downtown, indoors and into areas that are currently plagued with weak reception, such as under tree limbs,” he wrote.
Enge led the Stanford GPS Lab following Parkinson’s retirement. Enge’s research focused on improving the capabilities of aeronautical navigation, but he also extended that reach into train, maritime and other areas of transportation that benefit from GPS tracking. He later co-founded the Stanford Center for Position, Navigation and Time in 2005. Sensing the increasing reliance the world would have on GPS, in later years Enge took an acute interest in the cybersecurity of positioning systems.
Enge held 30 US patents and several international patents, and was also a noted writer and editor. He co-authored or co-edited two textbooks on positioning systems and over 400 peer-reviewed academic papers. In 2011, he won a Summerfield Book Award for the best book published by the American Institute of Aeronautics and Astronautics.
Professionally, Enge was the recipient of numerous awards and honors, including election to the National Academy of Engineers, being named to the Air Force GPS Hall of Fame and receiving the GNSS Signals Award from GPS World magazine. He was president of the Institute of Navigation (ION), an ION Fellow and recipient of the ION Thurlow and Kepler awards. Likewise, he was a Fellow of the IEEE and a recipient of the IEEE’s Kershner Award.
And yet, with all those demands on his time, Enge was known as a teacher and mentor. He designed a freshman course in electric cars and aircraft and helped launch a popular massive open online course (MOOC) for the GPS community outside Stanford.
“Even more important than his technical contributions were Per’s contributions to our community through education, advising and mentorship,” said Todd Walter, a friend and senior research engineer at Stanford. “He leaves behind a strong legacy of students, co-workers and colleagues who have been inspired by his genuine joy in being able to work in such an exciting field.”
A middling student until he discovered libraries
Per Kristian Enge was born Oct. 29, 1953, in Bergen, Norway. He immigrated at the age of 2 to the United States with his father, Harald, a professor of nuclear physics at MIT, and mother, Grete, a woman of wide-ranging interests, including a Master of Fine Arts degree.
Enge earned his BS in electrical engineering at the University of Massachusetts at Amherst in 1975 and his MS and PhD at the University of Illinois Urbana-Champaign in 1979 and 1983, respectively. He met his wife of 38 years, Elaine, while at UMass. His son, Nick, a Stanford graduate and now a lecturer at the University of Texas at Austin, said that despite his academic upbringing his dad was a middling student until Elaine introduced him to the library at UMass, where she was most often found.
While pursuing his advanced degrees, Enge worked in industry, where he contributed to the first solid-state Loran transmitters. He then took a position as assistant professor at Worcester Polytechnic Institute, where he designed a positioning system for maritime and land users that is still in use. That work drew the attention of the Stanford GPS Lab. Soon, Enge was recruited for a one-year visiting professorship that was quickly extended another year and then to a research professorship. Enge joined Stanford full time in 1993.
“We pulled every string we could to keep him here. We did a regular faculty search for the best person in the GPS field,” friend and fellow Stanford professor David Powell says, “and he came out on top of all applicants.”
In his personal time, Enge enjoyed traveling with his family, riding his electric bike and grilling fish, and he was known for a quick wit and sense of humor.
“Per had a very distinctive and utterly unreserved laugh,” Walter said. “In a crowded room, it was his own unique brand of a guidance system.”
“Per prided himself on being Norwegian, who tend to look at things in dark ways, but he was anything but dark. He was extremely optimistic and positive. Always,” Parkinson said.
Enge is survived by his wife, Elaine, of Mountain View, and a son, Nick, of Austin.