Abstract: This article establishes the geometric model of an airborne bistatic synthetic aperture radar (SAR) for the parallel squint mode and presents the expression of the radar echoes, and then derives its two-dimensional spectrum with an analysis of its characteristics. In the two-dimensional frequency domain, the point targets in the center of the observed scene are precisely imaged by multiplying the focusing function, and then the Chirp-Z transforms (CZTs) are employed to correct the range cell migration of the target echoes in either side of the center points. Finally, radar images are generated by the inverse Fourier transform on the azimuth direction. Since the algorithm utilizes the property of the CZT to process the nonlinear modulation frequency signals, the processing procedure is simplified, and computational efficiency and imaging precision are greatly improved. The simulation tests validate this new algorithm based on the CZT to process the data of the airborne bistatic SAR for the parallel squint mode.

Key words: synthetic aperture radar, two-dimensional frequency spectrum, focusing function, Chirp-Z transform, imaging algorithm