Charles C. Counselman III '64, SM '65, PhD '69
MIT professor emeritus advanced GPS technology
In 1979, Chuck Counselman gave an after-dinner speech at the International Union of Geodesy and Geophysics meeting in Canberra, Australia. The MIT professor used the opportunity to describe a little something he’d come up with: a way to measure, with millimeter-level accuracy, the position of one point on Earth with respect to another point hundreds of kilometers away. The audience reacted with stunned disbelief. “It was as if I’d told them that in my spare time, in the basement, I’d cured cancer,” Counselman says.
A chief NASA scientist stood up and labeled Counselman’s invention “snake oil.” Far from snake oil, however, it was a fresh way to harness the United States’ new Global Positioning System (GPS) satellites. Counselman had done it by combining his expertise in radio and astronomy.
Each GPS satellite broadcasts a signal that, like other radio signals, is generated by modulating, or varying, a “carrier” wave to convey information. Counselman was the first person to compare the carrier waves of these signals instead of the coded modulation of the waves. The carrier wavelength was so short—about 190 millimeters—that the resulting position uncertainty was smaller by a factor of 1,000 than what the Department of Defense and NASA were getting with the modulated waves. He also configured the receivers differently, winnowing multiple antennas and channels down to a single omnidirectional antenna and one channel so as to tune in to and read a composite signal from all the satellites in the sky. With fewer components, Counselman’s receivers were simpler, more compact, and cheaper to make. He called them MITES, for “miniature interferometer terminals for Earth surveying”—or “MIT engineering success,” he says. He proved his technology in a series of demonstrations in the early 1980s and was subsequently granted 36 patents.
Counselman earned his first two MIT degrees in electrical engineering and lived at Chi Phi as an undergraduate. “We did everything—hired the cook, bought the food, cleaned the house, upgraded the heating system,” he says. “It was good training for adult life.” He met his wife, Eleanor, at a Wellesley mixer; they have a son and a daughter.
Now a professor emeritus, he completed his aero/astro PhD and taught planetary science, astronomy, and electrical engineering at MIT until 2002. His economics minor has come in handy in chats at the tennis club, where he plays with Nobel laureates in economics.
Recently, he was exploring the Deutches Museum in Munich and saw one of his receivers in a huge glass display. “I just about fell over,” he says. “I didn’t even have my camera with me.” In 2008, the American Geophysical Union gave Counselman its Charles A. Whitten Medal for “outstanding achievements in research on the form and dynamics of the Earth and planets.” The organization noted that GPS receivers based on Counselman’s technology are ubiquitous, portable, and inexpensive.