Internal Calibration for Airborne X-Band DBF-SAR Imaging

Digital beamforming (DBF) synthetic aperture radar (DBSAR) is a promising candidate to overcome the constraint of minimum antenna area in the traditional single-channel synthetic aperture radar (SAR) system for achieving high-resolution and wide-swath (HRWS) image. On reception, DBF technology in elevation can significantly improve the system performance such as its sensitivity, ambiguity level, and the output signal-to-noise ratio (SNR) by Scan-On-Receive (SCORE). However, the inevitable channel mismatch will result in a beam-pointing error and further deteriorate the output SNR in the final SAR images. In this letter, the configuration of the 16-channel DBF-SAR system is described. A scheme of semi-physical simulation testbed for 1-D point target imaging is designed. Based on this, a detailed internal calibration technique combined with DBSAR mode is proposed to calibrate the channel mismatch and thus improve the SAR image quality. The real 1-D raw data experiment is performed to validate the proposed scheme. Finally, the imaging results from the practical flight experiment are shown and analyzed.

Automated summary

Digital beamforming synthetic aperture radar is a promising technology to improve the performance of radar systems for high-resolution and wide-swath imaging. This letter describes the configuration of a 16-channel DBF-SAR system and proposes an internal calibration technique to enhance SAR image quality.