Evaluating an S-band ground-based synthetic aperture radar imaging system for LFMCW SAR processing

Ground-based synthetic aperture radar (GBSAR) imaging systems are used extensively in earth observation and remote sensing applications. They are lightweight, costefficient, and resolve the main limitations of airborne and spaceborne SAR systems, such as low data collection rate, complicated implantation, and inefficient viewing angle to the imaging scene. This paper evaluates the signal processing results of the developed and implemented GBSAR system at the microwave remote sensing laboratory (MRESL) of the University of Tehran. The radar sensor consists of linear frequency modulated continuous wave (LFMCW) operating in Sband with 330 MHz of bandwidth that is mounted on a 1.4 m linear rail with a stepper motor. The radar sensor moves every 1 cm and records the backscattered echoes. After the dechirping process and digitizing, the recorded signal is stored in a twodimensional array, known as SAR 2D raw matrix. Experiments were conducted by illuminating the SAR sensor toward a scene containing corner reflectors. SAR raw data were processed by implementing the backprojection algorithm, and results were evaluated and compared with numerical simulations. Furthermore, the Hann window was employed as a weighting function on the raw signal, and its effect was evaluated on the resulting SAR image. The obtained results are promising and show the effectiveness of the developed GBSAR in the discrimination of targets at two range and cross-range directions.