Dangling from a weather balloon 80,000 feet above New Mexico, a pair of antennas sticks out from a Styrofoam cooler. From that height, the blackness of space presses against Earth’s blue skies. But the antennas are not captivated by the breathtaking view. Instead, they listen for signals that could make air travel safer.
Researchers from Sandia and Ohio State University are taking experimental navigation technology to the skies, pioneering a backup system to keep an airplane on course when it cannot rely on global positioning system satellites.
More than 15 miles below the floating cooler, cell phone towers emit a steady hum of radio frequency waves. Hundreds of miles above, non-GPS communications satellites do the same.
The idea is to use these alternative signals to calculate a vehicle’s position and velocity.