分布式全相参雷达正交频分LFM信号设计及性能分析  

OFD-LFM signal design and performance analysis for distributed aperture fully coherent radar

作　　者：宋靖[1] 牛朝阳[1] 张剑云[1] 

机构地区：[1]合肥电子工程学院,合肥230037

出　　处：《中国科学：信息科学》2015年第8期968-984,共17页Scientia Sinica(Informationis)

摘　　要：高精度估计相干参数——时延差和相位差是实现分布式全相参(DAFC)雷达收发全相参的前提与核心,输出信噪比增益(o SNRg)是衡量DAFC雷达性能的重要指标.本文将正交频分LFM(OFD-LFM)信号设计与峰值法相结合,探讨了信号参数设置对相干参数估计精度和o SNRg的影响,分析了高精度相干参数估计和高o SNRg所需的信号设计要求.首先分别建立了DAFC雷达工作在多输入多输出(MIMO)和全相参(FC)模式下的信号模型;然后研究了相干参数估计误差来源,重点分析了载频距离对相位差估计精度的影响;另外,在载频距离选择合适的前提下,给出了最优载频大小设置以获得最佳相位差估计精度和o SNRg.理论和实验表明:设计的OFD-LFM信号作为发射波形时,峰值法获得的相干参数估计精度和o SNRg接近发射理想正交波形时的水平.The estimation of coherent parameters that comprise time delay differences and phase differences with high accuracy is essential to realize transmitting and receiving coherence for distributed aperture fully coherent（DAFC） radar, and the output signal-to-noise ratio gain（o SNRg） is an important attribute used to measure DAFC radar performance. By combining the design of orthogonal frequency division-linear frequency modulation（OFD-LFM） signals with the peak picking algorithm, the impact of signal parameter settings on the estimation accuracy of coherent parameters and o SNRg are studied, and the signal design requirements to obtain high-precision estimation for coherent parameters and high o SNRg are analyzed in this paper. First, the two signal models for DAFC radar are established in multiple-input multiple-output（MIMO） and fully coherent（FC）modes, respectively. The source of coherent parameter estimation error and the impacts of carrier frequency distance on the estimation accuracy of phase differences are then deeply analyzed. Finally, under a condition of reasonable carrier frequency distance, the optimal carrier frequency value is given to achieve the best estimation accuracy of phase differences and the highest o SNRg. The results of simulation and theoretical calculation show that the estimation accuracy of transmitted OFD-LFM signals designed with coherent parameters and o SNRg by peak picking is close to that accomplished by peak picking with the transmission of ideal orthogonal signals.

关 键 词：波形设计 峰值法 参数估计 分布式 全相参 输出信噪比增益(oSNRg) 

分 类 号：TN957.51[电子电信—信号与信息处理]