Roger Lee Easton Sr. (April 30, 1921 – May 8, 2014) was an American physicist and state representative[1] who was the principal inventor and designer of the Global Positioning System, along with Ivan A.

When Sputnik I was launched, Easton extended the system to actively follow unknown orbiting satellites.

[2] Later in his career at NRL, Easton conceived, patented, and led the development of essential enabling technologies for the United States Global Positioning System (GPS).

During the 1960s and early 1970s he developed a time-based navigational system with passive ranging, circular orbits, and space-borne high precision clocks placed in satellites.

[7] On March 31, 2010, Easton was inducted into the National Inventors Hall of Fame and presented the NIHF Medal of Honor for the development of TIMed navigATION (TIMATION – U.S. Patent 3,789,409) that provided both accurate position and precise time to terrestrial based observers, an important foundation for contemporary Global Positioning Systems.