GPS signals help drivers to navigate to their destinations. (Credit: NASA)
PASADENA, Calif. (NASA PR) — Navigating to within three inches of your destination is made possible by algorithms and software developed by NASA. These power a NASA system that augments the raw navigation signals provided by the U.S. Air Force’s GPS satellites to support airplane navigation around the world, direct emergency responders and, soon, guide self-driving cars.
The Air Force began launching global positioning satellites in 1978, and it continues to operate and maintain the satellite network to this day. But over the decades, NASA has played a critical role in improving the system we rely on in our daily lives.
GPS satellites orbit thousands of miles above Earth, which means there are delays and distortions as the signals they send pass through the atmosphere. The signals are also subject to errors in satellite positions and noise and drift in the satellites’ atomic clocks.
As a result, positions based on raw data from GPS can be off by up to 30 feet. In contrast, corrected results from NASA’s Global Differential GPS (GDGPS) can be accurate to within three inches.
At the time the first GPS satellites were launching, NASA’s ...