Autonomous Aircraft
Stanford demonstrated the first non-military GPS guided autonomous aircraft (or UAV) circa 1996. Commercial, non-military GPS-guided UAVs (or drones) have become commonplace for use by commercial companies and/or hobbyists.
In this research, the objective was to prove that GPS alone was sufficient to control an unmanned vehicle from takeoff to precision landing. To achieve control, the ability to sense position and orientation accurately and robustly was necessary.
The gasoline powered model aircraft shown below has a twelve foot wingspan and was instrumented with 4 L1-only GPS antennas. One antenna was installed on each wing tip and one at the nose and tail.
After resolving cycle ambiguities, L1 carrier phase difference measurements between a base station antenna (fixed on the ground) and the aircraft nose antenna were used to determine aircraft position relative to the ground antenna at 10 Hz update rate. Carrier phase differences among the aircraft mounted antennas were used to determine the aircraft attitude at 10 Hz update rate.
Based on the GPS measurements, the aircraft demonstrated the ability to repetitively take off, fly a predetermined trajectory and perform a precision landing.
This research showed that GPS could be used to determine 6 degrees of freedom on a dynamic platform and could perform with sufficient robustness and update rate to control an air vehicle.
Today, GNSS is ubiquitous for providing guidance to UAV’s, but is not typically used in inner loop control.
Stanford originally received funding for these projects from the U.S. Department of Transportation (DOT) and the Federal Aviation Administration (FAA).
View the Wikipedia article on Unmanned Aerial Verhicles for more details.
See also: GPS for Airplane Navigation
SCPNT Historical Video Clips circa 1994 - 1998
The Development & Testing of the Stanford Integrity Beacon Landing System
An 11-minute narrated video chronicling the evolution of Stanford's Integrity Beacon automated airplane landing system from GPS-based spacecraft attitude and control guidance technology developed for the Stanford/NASA landmark Gravity Probe B mission testing Albert Einstein's general theory of relativity and its extension and augmentation by a team of Stanford graduate students into a combination satellite and ground-based pseudo-satellite (integrity beacon) system that could land a Boeing 737 aircraft autonomously in inclement (restricted visibility) weather.
This video courtesy of Stanford University Archives
GPS/Integrity Beacon B-Roll Video Segments:
Video segments showing all aspects of the GPS-related technologies used in automated airplane navigation, takeoffs and landings in 1994. This video features the team of graduate students from the Stanford University GPS Lab who pioneered and developed these technologies.
This video courtesy of Stanford University Archives
CNN and San Francisco Bay Area Television Stories:
Stanford GPS Lab auto-landing tests of a United Airlines Boeing 737 aircraft by Clark Cohen and fellow graduate students.
