Optimizing GPS for UAVs

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Assistant Prof. Grace Gao’s fundamental work in honing reliable and robust positioning, navigation, and timing for the Global Positioning System contributes significantly to the ever-growing technologies of unmanned aerial vehicles, power systems, and robotics.

Recognizing her groundbreaking research, the University of Illinois Center for Advanced Study (CAS) has chosen Gao, an Aerospace Engineering at Illinois faculty member, as a 2017-18 Beckman Fellow, an honor granting her a release from teaching to pursue research for a semester. 

The Fellowship will allow Gao time to work on her project, “Monitoring and Improving Positioning Integrity for Unmanned Aerial Vehicles.” The work addresses not only positioning accuracy of UAVs, but also the confidence in that accuracy, or its integrity. In urban settings, for example, tall buildings can undermine the accuracy of satellite rays to positioning systems for UAVS or self-driving cars. The signals can be blocked, or misdirected by reflective surfaces. 

Gao’s team plans to turn the misdirection into a useful navigation source. “Instead of trying to mitigate the multipath error, we turn the reflected multipath ray into a direct line-of-sight (LOS) ray transmitted from a virtual satellite mirrored from the building surface,” according to the project proposal. 

Gao and her students designed a unique, highly visible experiment in Spring 2016 to collect data for the project. The team set up a drone to fly within the confines of a cage carried on a flatbed truck as it was driven throughout Urbana-Champaign. The experiment was the researchers’ method of resolving their need to gather data without violating Federal Aviation Administration restrictions on flying UAVs in crowded urban settings.