Lightweight SAR: A Two-Bit Strategy

Abstract

By benefiting from one-bit sampling, the system deployment of synthetic aperture radar (SAR) can be greatly simplified. However, it usually requires a high oversampling rate to avoid the apparent degradation in imagery, which counteracts the storage-saving advantages. In this paper, a two-bit lightweight SAR imaging strategy is proposed to take the advantage of one-bit quantization in simplification but get rid of the requirement of sampling at a high rate. Specifically, based on one-bit quantization, an extra bit after an appropriate phase shifting is introduced to suppress the harmonics resulting from the nonlinear effect of quantization. In this way, the awkward nonlinearity in conventional one-bit schemes can be tackled by the nonlinearity generated with the newly introduced bit. Hence, this improves the imaging quality. In addition, the proposed method does not rely on fast sampling. The harmonic suppression effect is retained under low-sampling-rate conditions. Therefore, the amount of data acquired will decrease dramatically. This will benefit the whole process of imaging and, consequently, lighten the system burden and cost. The theoretical analysis and experimental results showcase the superiority of the proposed method.