A Synthetic Aperture Radar Imaging Mode Utilizing Frequency Scan for Time-of-Echo Compression

The synthetic aperture radar (SAR) imaging mode described in this article utilizes the available signal bandwidth to form a narrow frequency-scanning transmit antenna beam illuminating the swath of interest from far to near range. The imaging technique is named frequency scan for time-of-echo compression (f-STEC), because, for a proper choice of mode parameters, the radar echo duration is reduced, i.e., compressed. This article provides a detailed analysis of the f-STEC imaging technique and derives the operational and performance parameters as well as—to the authors’ knowledge—for the first time, analytic expressions for the f-STEC timing constraints. Furthermore, the performance and trade space are reported and compared to both conventional and modern, i.e., digital beamforming imaging modes. The f-STEC imaging technique is shown to be specifically advantageous for SAR systems operating at higher carrier frequencies or an attractive add-on for state-of-the-art SAR instruments.