联合波形重构的数字调制信号直接定位方法

Direct Position Determination for Digital Modulation Signals Based on Waveform Reconstruction

直接定位(Direct Position Determination,DPD)算法相比于传统两步定位法,在低信噪比和复杂环境下具备更高定位精度和更强鲁棒性。研究表明加入信号波形信息能够有效提升DPD算法定位精度,但在实际无源定位场景中信号波形往往难以先验已知,未知信号波形的DPD算法精度受限。针对这一问题,本文围绕无源定位系统中普遍存在的调制方式已知,但符号信息未知的数字调制信号,提出一种联合波形重构的数字调制信号直接定位(Direct Position Determination for digital Modulation signals,MDPD)方法。该方法依据最大似然准则,基于调制信号成型、接收阵列与辐射源位置几何关系,构建阵列接收信号关于信源符号和位置参数联合估计的代价函数,利用交替迭代降低信号高维搜索给参数联合估计带来的计算复杂度。仿真实验结果验证了联合波形重构的MDPD方法可行性,同时通过与已有两类定位方法的对比实验,得到本文MDPD可以达到更高定位精度,并在信噪比增加时收敛到渐进最优定位精度。

Compared to the traditional two-step positioning method,the Direct Position Determination(DPD)algorithm has higher positioning accuracy and stronger robustness especially in low SNR and complex environment.It has been proven that the addition of signal waveform information can effectively improve the positioning accuracy of DPD algorithm.However,the signal waveform in the actual passive location scenario is often difficult to know a priori,which limits the DPD algorithm accuracy with unknown signal.Aiming at this limitation,this paper proposes a digital Modulation signals DPD method(MDPD)combined by waveform reconstruction,for the digital modulation signals with unknown symbol information existing commonly in passive location system.According to the digital modulation signal forming method,the geometric relationship of the receive array and the radiation source,the method constructs the array antenna likelihood function on the location parameters and the transmitted symbol,and then reduces the computational complexity of high dimensional search by alternating iteration to parameter combination estimation.The simulation results verify the feasibility of MDPD algorithm with waveform reconstruction.Meanwhile,compared with two existing localization algorithms,the proposed MDPD is proved to achieve higher positioning accuracy and converge to asymptotic optimality positioning accuracy.