MIMO雷达三维成像自适应Off-grid校正方法

Adaptive Off-grid Calibration Method for MIMO Radar 3D Imaging

在压缩感知成像算法中,真实目标点一般不会恰好落在预先划定的网格点上,这种网格偏离(Off-grid)问题会带来真实回波与测量矩阵之间的失配,严重降低雷达成像的性能。针对多输入多输出(MIMO)雷达3维成像的网格失配问题,该文提出一种自适应的Off-grid校正方法,基于Off-grid目标的稀疏回波模型构造贝叶斯概率密度函数,采用最大后验概率(MAP)方法求解含有失配偏差的稀疏像。与传统方法相比,该方法可以充分利用失配参数的先验信息,自适应地更新参数,降低了失配误差的影响,并能实现对稀疏目标和噪声功率的高精度估计。仿真结果表明,该方法可以有效地实现对网格失配的优化,具有精确且稳定的成像性能。

In Compressive Sensing (CS) imaging algorithms, the true targets usually can not locate on the predefined grids exactly. Such Off-grid problems result in mismatch between true echo and measurement matrix, which seriously degrades the performance of radar imaging. An adaptive calibration method is proposed to solve the off-grid problems in MIMO radar Three-Dimensional (3D) imaging. Bayesian probability density functions can be constructed based on the sparse echo model of Off-grid targets, and the Maximum A Posteriori (MAP) method is used to obtain sparse imaging with mismatch errors. Compared with the traditional methods, the proposed method can make full use of mismatch parameters’ priori information and adaptively update the parameters, which can reduce the influence of mismatch errors, and achieve high-precision estimation for sparse targets and noise power. Finally, the simulation results confirm that the proposed method can effectively optimize mismatch errors with accurate and stable imaging performance.