基于贝叶斯压缩感知的FD-MIMO雷达Off-Grid目标稀疏成像  

Bayesian Compressive Sensing-Based Sparse Imaging for Off-Grid Target in Frequency Diverse MIMO Radar

作　　者：王天云[1,2] 陆新飞 丁丽[2] 尹治平[3] 陈卫东[2] 

机构地区：[1]中国卫星海上测控部,江苏江阴214431 [2]中国科学技术大学中科院电磁空间信息重点实验室,安徽合肥230027 [3]合肥工业大学光电技术研究院,安徽合肥230009

出　　处：《电子学报》2016年第6期1314-1321,共8页Acta Electronica Sinica

基　　金：国家自然科学基金(No.61172155;No.61401140;No.61403421);国家863计划项目资助课题(No.2013AA122903)

摘　　要：传统压缩感知(CS,Compressive Sensing)成像方法一般假定目标精确位于事先划定的成像网格上,实际中由于散射点空间位置是连续分布的,因此偏离网格(Off-grid)问题必然存在.这会引起真实回波测量值与默认系统观测矩阵之间失配,导致传统CS成像方法性能恶化.本文基于频率分集多输入多输出(FD-MIMO,Frequency Diverse Multiple-Input Multiple-Output)雷达,针对Off-grid目标提出了一种基于贝叶斯压缩感知的稀疏自聚焦(SAF-BCS,Sparse Autofocus Imaging Method Based on Bayesian Compressive Sensing)成像算法.该算法依据最大后验(MAP,Maximum A Posteriori)准则,利用变分贝叶斯学习技术求解含有Off-grid目标的稀疏像.与传统稀疏重构方法相比,所提方法充分利用了目标先验信息,可自适应调整参数,能够更好地反演稀疏目标,同时具有校正Off-grid目标的网格位置偏差以及估计噪声功率等优势.仿真结果表明SAF-BCS算法对网格划分不敏感,具有稳健的成像性能.Conventional compressive sensing （CS）imaging methods rely on the assumption that all scatterers in the ima-ging scene are located exactly on the pre-defined grids.However,since the scatterers are distributed in a continuous scene,the off-grid problem inevitably exists,which makes basis mismatch between echo measurement and the assumed sensing matrix,and leads to considerable performance degradation by CS-based methods.Therefore,this paper investigates the sparse imaging for off-grid target in frequency diverse multiple-input multiple-output （FD-MIMO）radar.A sparse autofocus imaging method based on Bayesian compressive sensing （SAF-BCS）is proposed.It employs the technique of variational Bayesian inference to achieve the imaging of off-grid scatterres in light of the criterion of maximum a posteriori （MAP）.Compared with the conventional sparse re-covery algorithms,the proposed method adequately utilizing the prior information of the target,is able to automatically tune pa-rameters,and thus can provide a better capability to correct the off-grid errors,and to estimate the noise power,etc.Simulation re-sults confirm that SAF-BCS is not sensitive to grid discretization,and has a robust imaging performance.

关 键 词：贝叶斯压缩感知 FD-MIMO雷达 Off-grid目标 变分贝叶斯学习 稀疏自聚焦成像 

分 类 号：TN958[电子电信—信号与信息处理]