Synthetic Aperture Radar Aboard an Unmanned Aerial System for Detecting Foreign Object Debris on Airport Runways

The detection of foreign object debris (FOD) is a critical safety issue in airport operations. Nowadays, the most advanced detection systems are high frequency radars installed along the runway. In this article, the authors propose a synthetic aperture radar (SAR) aboard a small unmanned aerial system (UAS), a quadcopter, flying sideways over the runway as FOD detection system. This solution can operate during the daily airport operations and does not require permanent installations near the runways. To focus SAR images, an accurate knowledge of the platform position is needed. So, the hardest challenge in SAR imaging with UAS is an effective mitigation and compensation of uncontrolled movements. For this reason, a specific back propagation algorithm was developed. The FOD detection technique was tested in a general aviation airfield (Serristori, Arezzo, Italy) and in two Italian commercial airports: Milan Linate Airport (LIN), Olbia Costa Smeralda Airport (OLB).