共形FDA-MIMO波束图综合
Beampattern Synthesis for Conformal FDA-MIMO
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摘要: 共形频控多输入多输出(Frequency diverse array multiple input and multiple output,FDA-MIMO)系统的波束图由俯仰角、方位角、距离三维信息控制,能够进一步提高系统的自由度。随着人们对高分辨目标探测性能以及高空气动力学性能的需求增加,研究共形FDA-MIMO阵列波束图综合方法很有意义。本文详细推导了共形FDA-MIMO系统的信号建模和波束图分析的数学过程,并提出一种基于参数迭代的发射接收联合权向量优化算法以得到高分辨率的波束图。该算法首先建立一个二阶锥规划(Second-order cone programming,SOCP)模型,并利用交替方向乘子法(Alternating direction method of multipliers,ADMM)实现参数分离,原问题分为两个子问题。最后分别对各个子问题进行优化。数值仿真表明所提算法相比于传统算法性能更有优势,同时其收敛性得到验证。此外,为进一步分析系统特性,本文讨论了不同系统参数,如发射阵列阵元数、接收阵列阵元数、频控阵频偏大小以及不同频偏方式对本文所提算法下的波束图影响。Abstract: The beampattern of conformal frequency diverse array multiple input and multiple output (FDA-MIMO) system has three-dimensional information of elevation, azimuth and range, further improving the degree of freedom of the system. With the increasing demand for high-resolution target detection performance and high aerodynamic performance, it is meaningful to study the beampattern synthesis method of conformal FDA-MIMO arrays. In this paper, the mathematical derivation process of signal modeling was provided, and the process of joint transmitting and receiving beampattern analysis was derived in detail. For the sake of the high resolution beampattern, a joint transmitting and receiving weight vector optimization algorithm based on parameter iteration was proposed. In the proposed algorithm, a second-order cone programming (SOCP) model was firstly established, and the idea of alternating direction method of multipliers (ADMM) method was used to achieve separation of parameters, and then the original problem is split into two subproblems. Finally, the above-mentioned two subproblems were optimized, respectively. Numerical simulation results show that the proposed algorithm has better performance than the traditional algorithm, meanwhile its convergence is verified. In addition, in order to further analyze the characteristics of the system, the influence of different system parameters, such as the number of transmitting array elements, the number of receiving array elements, the size of frequency increment of FDA and different frequency increment coding methods, on the beampattern based on the proposed algorithm is also discussed in different simulation scenarios.