基于Capon谱估计的星载SAR自适应DBF研究  

Study on Adaptive Digital Beamforming for Spaceborne SAR Based on Capon Spatial Spectrum Estimation

作　　者：冯帆[1] 党红杏[1] 谭小敏[1] 

机构地区：[1]中国空间技术研究院西安分院,西安710100

出　　处：《雷达学报（中英文）》2014年第1期53-60,共8页Journal of Radars

摘　　要：在地形起伏较大的山地区域,星载SAR利用传统俯仰向数字波束形成(DBF)方法接收场景回波时,都会出现波束指向偏差的问题,这一偏差使得回波接收增益与信噪比降低。针对这一问题,该文提出一种基于Capon空间谱估计的星载SAR自适应DBF方法。该方法首先通过有限的回波数据来准确地估计出各距离门内信源的波达角(AOA),而后利用这些信息来更新接收波束的加权矢量,从而能够在任何时刻都使接收波束准确地指向信源位置,以此来改善回波增益与信噪比。仿真实验结果表明,该方法较传统的俯仰向波束扫描(SCORE)法有较大的性能改善,同时它还对系统及信源参数的变化有很强的鲁棒性。In rough mountainous areas, beam-pointing mismatch problems always arise when a spaceborne Synthetic Aperture Radar （SAR） uses the traditional Digital BeamForming （DBF） approach in elevation to receive echoes, leading to the degradation of the receiver’s gain and system Signal-to-Noise Ratio （SNR）. To solve this problem, an Adaptive Digital BeamForming （ADBF） approach based on the Capon spatial spectrum estimation is proposed. This approach first estimates the Angle Of Arrival （AOA） of the source signal in each range bin using the limited echo data. Then, it updates the weighting vector in the beamforming process, thereby enabling the receiving beams to precisely point to the signal source, and enhance the receiver’s gain and SNR. Simulation results suggest that the ADBF approach significantly improves the performance compared to the SCan-On-REceive （SCORE） approach, exhibiting robustness to system and source parameters variations.

关 键 词：星载合成孔径雷达(SAR) 空间谱估计 Capon法 自适应数字波束形成(ADBF) 接收增益 

分 类 号：TN958[电子电信—信号与信息处理]