基于EPC-MIMO编码设计的解距离模糊性能分析

中高脉冲重复频率雷达中, 目标的回波延迟时间大于发射脉冲的重复周期时会导致距离模糊。本文在多输入多输出(multiple-input multiple-output, MIMO)雷达中进行联合发射阵元与脉冲二维编码(element-pulse coding, EPC), 对阵元脉冲编码的设计方法进行了研究, 可实现距离解模糊。对基于Fourier正交基的编码设计进行推广, 提出了一般的EPC方法, 对于 M 个发射阵元, 可获得 M ! 种编码方式。引入期望距离区与模糊距离区的信号模糊比(signal-to-ambiguous-plus-noise ratio, SANR)作为解模糊性能的评估准则, 进行了性能分析。针对角度误差提出了稳健的权矢量优化方法, 进一步提高了解距离模糊的稳健性。仿真实验验证了所提方法的有效性, 不同编码方式在理想情况下均能有效分离不同距离区的目标, 且优化权矢量后 M ! 种编码方式对应的解距离模糊性能相近。

Analysis on the performance of resolving range ambiguity based on a coding scheme design for EPC-MIMO

In the medium and high pulse repetition frequency radar, the range ambiguity will occur if the time delay of the target's echo is larger than the transmitted pulse repetition time. To deal with this problem, the element-pulse coding (EPC) in joint transmit elements and pulses is performed in multiple-input multiple-output (MIMO) radar, where the scheme of EPC is studied. Firstly, the coding schemes based on the Fourier orthogonal basis are extended, and the general EPC scheme is proposed, where M ! kinds of coding schemes can be obtained with M transmit elements. Then, the range ambiguity resolvability of the EPC-MIMO radar is analyzed with the signal-to-ambiguous-plus-noise ratio (SANR). Finally, the weight vector optimization method corresponding to angle error is proposed, which further improves the robustness of range ambiguity resolution. Simulation examples are provided to confirm the effectiveness of the proposed method, showing that the targets can be effectively separated in different range regions with the proposed coding schemes under ideal conditions. Along the same line of reasoning, after optimizing the weight vector, the performances of range ambiguity resolution for M ! coding schemes are similar.