信号相关杂波下MIMO探通一体化信号设计方法

MIMO DFRC Signal Design in Signal-dependent Clutters

  • 摘要: 以探测功能为主的雷达通信一体化(Dual Function Radar and Communication, DFRC)系统发射一体化信号,能够在保证探测性能的条件下,尽可能高效地与合作目标通信,使其在设备集约化要求高的电磁对抗环境中占有一席之地。因此,探通一体化信号设计是以探测功能为主DFRC系统研究的关键科学问题之一。但电磁对抗环境复杂多变,可能存在非均匀、多变和强独立散射的散射体与雷达探测信号相互作用,使DFRC系统接收的回波中含有在空间上呈现非均匀特性的杂波分量,从而给雷达目标检测带来挑战。 针对杂波环境中DFRC系统探测性能下降的问题,本文采用认知系统架构,获取空间非均匀杂波先验知识,以信干噪比(Signal Interference to Noise Ratio, SINR)为准则,保障雷达的探测性能。引入发射方向图主瓣和旁瓣约束,使天线方向图具有低旁瓣特性同时集中探测能量在目标所在的方位,进一步保障探测性能。此外,考虑信号变模约束平衡雷达系统发射机功放的非线性失真和优化自由度。采用了一种空间合成信号频谱置零的方法实现信息传输,构建了通信调制约束。为求解上述多约束高维非凸优化问题,研究了一种联合序列块增强(Sequential Block Enhancement, SBE)、丁克尔巴赫(Dinkelbach’s Iterative Procedure, DIP)、凸序列逼近(Sequential Convex Approximation, SCA)和内点法(Interior Point Method, IPM)的迭代求解算法。理论分析了该算法的收敛性和计算复杂度。仿真结果表明,所设计的波形能够在信号相关旁瓣杂波下,同时实现探测和多用户通信。

     

    Abstract: ‍ ‍The radar-centric Dual Function Radar and Communication (DFRC) system with communication as the secondary function, is mainly used in the military field. This system capitalizes on the hardware and spectral resources of the radar to communicate with cooperative targets via transmitting dual-function signal. As a result, the integrated signal design is one of the key scientific issues. Due to the presence of non-uniform, changeable and strong independent clutters mixed with radar detection signals in the electromagnetic countermeasure environment, the echo received by DFRC system contains clutters which increases the difficulty of target detection. In this paper, based on the prior knowledge of sidelobe signal-dependent clutters and targets, we formulate the radar-centric DFRC signal design optimization problem through relying on the maximization of the Signal Interference to Noise Ratio (SINR) to enhance radar detectability. Meanwhile, the mainlobe width and sidelobe constraints to cohere the beampattern main energy on the spatial region of interest are forced, respectively. Besides, variable modulus restriction to comply with the current hardware technique. A Sequential Block Enhancement (SBE) framework that alternately updates each waveform in each emitting antenna is developed to monotonically increase SINR. Each block involves the Dinkelbach’s Iterative Procedure (DIP), Sequential Convex Approximation (SCA) and Interior Point Method (IPM) to obtain single waveform. The computational complexity and convergence of the algorithm are analyzed. The designed radar-centric DFRC signal can realize both detection and communication functions simultaneously in sidelobe signal-dependent clutters.

     

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