Millimeter-wave Ground-based Synthetic Aperture Radar Imaging for Foreign Object Debris Detection: Experimental Studies at Short Ranges

In this paper, millimeter-wave imaging of foreign object debris (FOD)-type objects on the ground is studied with the help of ground-based synthetic aperture radar (GB-SAR) technique. To test the feasibility of detecting runway FODs with this technique, some preliminary experiments are conducted within short antenna-to-target ranges of small imaging patches. An automated stripmap GB-SAR system with stepped-frequency transmission is constructed together with a quasi-monostatic data collection operation. The imaging experiments for various braces and screws are then carried out by using 32-36 GHz and 90-95 GHz frequency bands of the millimeter-wave. Images reconstructed by a matched-filter based algorithm are analyzed to determine the proper system parameters for an efficient imaging and to comprehend the factors against a successful detection. Results demonstrate the capability of GB-SAR imaging in accurately locating these FOD-like targets under near-range operating conditions.