Phase integration for two dimensional radar image formation

Abstract

Radar imaging is traditionally performed by wideband radar systems to achieve high range resolution of objects. Unfortunately due to cost, frequency allocation, or physical limitations, most radars are unable to operate over a broad range of frequencies. We propose a methodology to achieve high range resolution by phase integration in the frequency domain of a narrowband radar signal. This process compares with the radio camera interferometry approach in that it uses a phased array to achieve spatial resolution and a ground penetration image formation process that spatially samples a region in two dimensions. Our approach unifies the previous approaches, and integrate return signals in the frequency domain which simplifies the registration of the return signal. We begin by describing the basic methodology of collecting data with a two dimensional antenna array using a narrowband linear FM signal. We then describe how each phase bin is converted to the frequency domain and integrated in time. Next, we discuss the Fourier transform followed by the pulse decompression process. Finally we discuss the sampling approach for the two dimensional synthetic aperture and show simulated results.