Gladys Mae West was an American mathematician whose calculations of the shape of the Earth became part of the foundation of the Global Positioning System. Born Gladys Mae Brown on October 27, 1930, in Sutherland, in rural Dinwiddie County, Virginia, she grew up on a small farm owned by her parents in a community of sharecroppers during the Jim Crow era. Her mother also worked in a tobacco factory, and her father worked for the railroad. From a young age she helped harvest corn, cotton, and tobacco, and she decided early that education would be her way out of farm labor. She and her siblings walked several miles to a poorly equipped segregated school. Teachers encouraged her aptitude for mathematics. At her high school the top two graduates each year received full scholarships to Virginia State College, a historically Black institution in Petersburg. She graduated as valedictorian in 1948 and became the first in her family to attend college.
At Virginia State she studied mathematics, a field then dominated by men, and joined the Alpha Kappa Alpha sorority. She earned a bachelor of science in mathematics in 1952 and taught mathematics and science for about two years in segregated schools in Waverly, Virginia. She returned to Virginia State and completed a master’s degree in mathematics in 1955, then briefly taught again in Martinsville. Applications for state government jobs in segregated Virginia were unsuccessful; positions she sought were given to white men. In 1956, the year after President Eisenhower’s order barring racial discrimination in federal hiring, she was hired as a mathematician at the U.S. Naval Proving Ground in Dahlgren, Virginia, later the Naval Surface Warfare Center Dahlgren Division. She was only the second Black woman hired there and one of only four Black employees at the time. The work involved classified military research, and she performed large volumes of calculation by hand and later by computer programming.
At Dahlgren she met Ira V. West, another Black mathematician. They married in 1957 and had three children. Both continued long careers at the base. Early in her tenure she worked with large computers such as the Naval Ordnance Research Calculator. In 1962 she contributed to Project 29V, programming a computer to calculate the orbit of Pluto relative to Neptune. The effort required more than five billion arithmetic operations and nearly one hundred hours of machine time, and the team received recognition for demonstrating the regularity of that motion. Much of the laboratory’s work remained secret. Over the following decades the Department of Defense sought an accurate satellite navigation system, and the Navy developed elements of what became GPS.
West’s most consequential work concerned satellite geodesy: the mathematical modeling of Earth’s precise shape and gravitational field. Earth is not a perfect sphere. It is flattened at the poles, bulges at the equator, and is further distorted by variations in density, tides, and other forces. A practical model of that irregular surface is the geoid, a surface of constant gravitational potential that coincides approximately with mean sea level and its imagined continuation under the continents. Satellite ranging and radar altimetry can measure distances to the ocean surface, but converting those measurements into positions on land requires an accurate geoid and an accurate reference ellipsoid, together with reliable models of satellite orbits. West described one of her duties as calculating the geoid. She worked largely with data collected over water, so the calculations had to account for tides and related effects. She later wrote that the geoid model, the reference ellipsoid, and satellite orbit models were three elements without which satellites could not determine a position on Earth, and that continual refinement of those elements improved the resulting accuracy.
From the mid-1970s into the 1980s she used complex algorithms to account for gravitational, tidal, and other forces that distort Earth’s shape. She programmed the IBM 7030 Stretch computer to produce increasingly refined calculations. She served as project manager for the Seasat radar altimetry project. Seasat, launched in 1978, was the first satellite designed to monitor the oceans with radar. She oversaw a small team that processed altimeter data into a detailed geodetic Earth model. That model, and later updates, became a building block for the orbits used by GPS satellites. She also led data-analysis work connected with other satellite missions, including GEOSAT, and published technical reports on the processing of satellite altimeter data. Captain Godfrey Weekes, a commanding officer at Dahlgren, later summarized her role by noting that she rose through the ranks, worked on satellite geodesy, and contributed to the accuracy of GPS and the measurement of satellite data. Without an effective Earth model, positioning errors would have been too large for reliable navigation.
While employed she earned a second master’s degree, in public administration, from the University of Oklahoma in 1973. She retired from Dahlgren in 1998 after forty-two years. In 2000 she completed a PhD in public administration from Virginia Tech through distance learning. For many years her contribution remained little known outside technical circles. Public recognition arrived late. In 2018 the Virginia General Assembly formally recognized her work on GPS. That same year she was inducted into the Air Force Space and Missile Pioneers Hall of Fame and named one of the BBC’s 100 Women. She received the Webby Lifetime Achievement Award for the development of satellite geodesy models, and in 2024 the IEEE President’s Award for mathematical modeling and development of satellite geodesy models that played a pivotal role in GPS. Profiles in the press often described her as a hidden figure of the system that now guides phones, ships, aircraft, and surveying equipment.
West herself used GPS sparingly and preferred paper maps. She lived for many years in Virginia and died on January 17, 2026, at the age of 95. Her career illustrates how precise, incremental mathematical labor, performed under segregation and later under classification rules, can become infrastructure used by billions of people. The satellites of GPS measure time and range with atomic clocks, but the conversion of those ranges into coordinates on the ground depends on knowing the shape and gravity field of the planet. West’s programming and analysis helped supply that knowledge.