Lightweight SAR: A 1.5-Bit Strategy

Nowadays lightweight radar has become an important technique in autonomous driving systems for its all-weather sensing ability. Synthetic aperture radar (SAR) imaging based on one-bit sampling is able to considerably simplify system deployment and cut down manufacturing costs. However, a high oversampling rate is usually required to avoid the performance degradation resulting from aliasing of one-bit quantization noise. This will counteract the storage saving advantages brought by low quantization level. In this paper, to facilitate its applicability on vehicle platforms, a lightweight strategy of 1.5-bit SAR imaging is devised to inherit the merit of one-bit quantization in simplification but circumvent the requirement of high sampling rate. Compared with one-bit quantization, only additional 0.5 bit per sample is introduced to alleviate the awkward harmonic problem due to the non-linear effect of quantization. In this way, the quality of SAR imagery can be significantly improved. Besides, the enhanced performance of the proposed method does not rely on the sampling rate. This will benefit the whole procedure of imaging and lighten the system burden and cost consequently. Theoretical analysis and experimental results from a real vehicular SAR system showcase the superiority of our 1.5-bit quantization approach.