基于单频时变阈值的1-bit SAR成像方法研究

1-bit SAR Imaging Method Based on Single-frequency Time-varying Threshold

该文提出一种基于单频时变阈值的1-bit合成孔径雷达(SAR)成像方法,通过将回波数据与时变阈值比较,将其量化为1-bit采样数据,从而降低SAR回波数据的位宽,达到简化系统、提升效率的目的。传统的1-bit采样将信号与0阈值比较,这将造成信号相对幅度的非线性失真,影响成像质量。而随机时变阈值虽然能够保留幅度信息,却会引入额外的类噪声干扰。单频时变阈值将能够有效地保留1-bit采样量化中丢失的相对幅度信息,同时避免引入类噪声干扰,有效地提高了1-bit采样量化下的SAR成像质量。通过仿真实验定量分析了算法的成像聚焦质量、幅度信息保持能力,并通过对场景目标的成像验证了算法的有效性。

This paper proposes a 1-bit Synthetic Aperture Radar （SAR） imaging method based on a single- frequency time-varying threshold. Synthetic aperture radar echoes are quantized to 1-bit sampling data by comparing the data with the threshold; this reduces the data-width of the SAR echoes, consequently simplifying the system and improving efficiency. The conventional 1-bit sampling compares the signal to a zero threshold, bringing nonlinear distortion to the relative amplitude and degrading the imaging quality. The random threshold can keep the amplitude information, but it introduces additional noise-like interferences. In contrary, the single-frequency time-varying threshold can maintain the amplitude information lost during the i-bit sampling and quantization, and at the same time, eliminate noise-like interferences; thus, the imaging quality of SAR using 1-bit sampling and quantization can be improved. The focusing quality and the amplitude- maintaining ability of the proposed approach is quantitatively analyzed, and the effectiveness of the approach is verified by an imaging experiment on a scene.