机翼可变阵列雷达的空时杂波建模与分析

Space-time Clutter Model Construction and Characteristic Analysis for Wing Flexible Array Radar

针对可变飞行器阵列雷达空时自适应处理应用场景,本文设计了三维机翼可变阵列雷达模型,通过阵列结构参数的变化实现阵列横向长度变化、阵列纵向宽度变化、阵列曲面高度变化三种变形方式,利用阵元空间位置矢量与阵列结构变化参数集的关系建立阵列的空时杂波信号模型,推导了机翼变形阵列的空域导向矢量和杂波协方差矩阵,通过矩阵块嵌套的理论证明了它的非Toeplitz结构特性。通过对多普勒域和空频域之间相关性的分析,揭示了需要在四维空间中表征机翼可变阵列雷达空时杂波分布的本质机理。仿真结果表明,机翼可变阵列雷达的空时杂波具有非平稳特性,阵列变形可以有效改变杂波自由度和杂波相关性,这为基于三维机翼阵列结构优化的杂波抑制方法研究提供了理论依据。

For aircraft flexible array radar space time adaptive processing application scenario,a three-dimensional(3-D)wing flexible array is designed in this paper.Three deformation modes of array transverse length change,array longitudinal width change and array surface height change are completed by the changing the array structure parameters.The spacetime clutter signal model is constructed based on the relationship between array elements space position vector and array structure deformation parameter set according to the deformable structure of circular arc.For three deformable modes of 3-D wing flexible array,the spatial steering vector and spatial temporal clutter covariance matrix are derived,and the non-Toeplitz structure of clutter covariance matrix is proved by the theory of matrix block nesting,which specifically analysis the elements in different matrix blocks by matrix block decomposition.Through the analysis of the correlation between the Doppler domain and the space frequency domain,the essential mechanism for manifesting the clutter distribution of the 3-D wing flexible array radar in the four-dimensional space is revealed.Different from the traditional airborne array radar,the space-time clutter property of the wing flexible array radar depends on the sampling range in the elevation dimension.The numerical simulation results demonstrate that the spatial temporal clutter of 3-D wing flexible array radar has nonstationary characteristics,for which the space time clutter power spectrum needs to be observed in four-dimensional space.It can be concluded that longitudinal width variation and surface height variation affect the eigenspectrum of spacetime clutter more seriously than transverse length variation.Range ambiguity has a more significant effect on deterioration of space-time clutter in the wing flexible array radar.The clutter degree of freedom(DOF)and clutter correlation can be effectively affected by array deformation,which provides a theoretical basis for clutter suppression method based on the optimization of flexible array structure and a theoretical support for airborne deformable array radar technology.