Identifying and Compensating for Phase Center Errors in Wing-Mounted Phased Arrays for Ice Sheet Sounding

Highly crevassed ice surfaces at ice-sheet margins and fast-flowing glaciers significantly scatter radar signals. The scattered signals, often known as surface clutter, mask weak echoes from the ice-bed interface. Large wing-mounted antenna arrays are essential to synthesizing low-sidelobe patterns to reduce surface clutter. However, wing-mounted arrays are susceptible to structural flexure, which causes amplitude and phase errors that result in shifting and filling of desired array pattern nulls. In this communication, we characterize the effects of wing flexure on array beamformation using a scaled array model, and we present a compensation method to mitigate phase center errors caused by wing flexure. The compensation greatly improves clutter suppression through improved null formation. Experimental results show that we obtain an average of 7.5 dB improvement in the signal-to-interference noise ratio.