Multiple antenna beam formation techniques for synthetic aperture radar

Abstract

A novel system concept for a multiple antenna beam synthetic aperture radar (SAR) is explored and developed for earth observation applications from an orbital spacecraft platform. The multiple beam concept is shown to offer improved performance characteristics over conventional side-looking SAR systems. Advantages of the multiple beam SAR include conserving transmitter peak power, relaxing system design constraints for avoiding ambiguous radar return signals, reducing the dynamic range requirement for the radar receiver and signal processor, and providing wide swath coverage at a nearly constant incident angle. The report provides a detailed analysis of the modulation and resolution characteristics of the radar return signal and relates the synthetic aperture signal requirements to the design of a multiple beam antenna array. Methods for multiple beam formation are discussed and a design example is presented to illustrate and identify important design implementation considerations. A critical evaluation of the multiple beam concept provides insight into the engineering development tasks required for successful implementation of an orbital multiple beam SAR.