Every time you open Google Maps or activate your phone’s GPS, there’s math running underneath it. Someone had to calculate the exact shape of the Earth (not a perfect sphere, but an irregular geoid with gravitational variations, tides, and deformations) with enough precision for a satellite to know where you are within a few meters. That person was Gladys West. She worked at a naval base in Virginia for 42 years. Almost nobody knew for decades.
A Mathematician from the Tobacco Fields
Gladys Mae Brown was born in 1930 in Dinwiddie County, Virginia, into a family of African American farmers. She grew up during the era of racial segregation, in a community where most people spent their lives working tobacco and cotton fields. She decided early on that she wouldn’t.
She studied hard enough to become her high school valedictorian, earning a scholarship to study mathematics at Virginia State College (now Virginia State University), a historically Black institution. She graduated in 1952, completed a master’s degree, taught math for two years, and in 1956 joined the Naval Surface Warfare Center Dahlgren Division. She was the second Black woman ever hired there — one of only four Black employees in total.
Work Without a Famous Name Attached
At Dahlgren, West began as a human computer, solving by hand equations that machines couldn’t yet process. Over time she moved to programming the Navy’s early large-scale computers, and eventually led satellite data analysis projects.
Her most consequential work was developing an extraordinarily precise mathematical model of the shape of the Earth — what scientists call the “geoid.” That required algorithms accounting for gravitational variations, tidal forces, and other factors that distort the planet’s shape. Without that model, satellites can’t calculate positions accurately. GPS needs to know exactly what the Earth looks like in order to know where you are.
From the Naval Base to Your Pocket
Through the 1970s and 1980s, West refined that model using data from multiple satellites, including the Geosat. In 1986 she published a technical reference manual on satellite radar altimeter data processing that is still cited in scientific publications today. By then, the U.S. military was already building GPS on that mathematical foundation.
She retired in 1998, after 42 years, without public recognition. The work was classified, the context was the Cold War, and individual credit was rarely assigned — especially not to a Black woman. As NPR reported when she died, without her mathematical model, “the extraordinary positioning, navigation, and timing accuracy of GPS would be impossible to achieve.” That precision is also the foundation of everything we now depend on for digital security: geolocation, fraud detection, logistics, emergency response.
The Line That Changed Everything
West’s story resurfaced in the most unexpected way. In 2017, a member of her Alpha Kappa Alpha sorority found a short biography West had written for an alumni event. It included, almost in passing, a line about her role in developing GPS.
That line circulated, reached the Navy, and triggered a recognition that was late but clear. In 2018 she was inducted into the Air Force Space and Missile Pioneers Hall of Fame in a ceremony at the Pentagon. That same year the BBC named her one of its 100 Women. In 2021 she received the Prince Philip Medal from the UK’s Royal Academy of Engineering. That same year, she published her memoir, It Began with a Dream. And the gender gap in tech that kept her invisible for decades is the same gap that costs the field contributions it can’t even measure, because it never knew they were there.
She died on January 17, 2026, at 95. Her work is still running in every phone on the planet.
What She Said About Her Own Story
When asked why she had never talked about her role in GPS, West answered: “I thought it was my job. I never bragged about what I did.” A sentence that says a lot about her — but also about the system that made that silence possible.
This is the eighth installment of the Women Who Built Technology series. You can also read the entries on Radia Perlman, Ada Lovelace, Grace Hopper, Margaret Hamilton, Hedy Lamarr, Ida Holz, and Hu Qiheng.
