基于非均匀时间调制的单通道比幅测向方法

Single-channel amplitude-comparison wideband direction finding method with nonuniform time modulation

[目的]为了解决传统时间调制测向中由载波频率变化引入的相位模糊而限制测向工作带宽的问题,提出一种基于非均匀时间调制的单通道比幅测向方法。[方法]通过对不同天线单元的接收信号进行非均匀周期调制,各天线接收信号的幅度信息无混叠地映射到对应调制频率的谐波中,进而提取出谐波幅度比,并结合查表法以实现单通道测向。基于数值仿真,验证所提方法的可行性,同时搭建一套宽带非均匀时间调制系统。[结果]实验结果显示,其测向绝对误差均值仅为0.21°(2.4 GHz)和0.18°(5.8 GHz)。[结论]所提方法可有效提高测向系统的工作带宽,具备结构简单、成本低、信号处理复杂度低以及宽带测向等优点。

[Objective]To overcome the problem of the limitation of working bandwidth due to the phase ambiguity caused by the carrier frequency's variation in conventional time-modulated direction finding,a single-channel direction finding method with nonuniform time modulation is proposed in this paper.[Methods]By modulating the signals received by different antenna elements at the same time with nonuniform periods,the amplitude information can be separately mapped to the corresponding modulated frequency without aliasing.With the amplitude ratio independently extracted from the harmonics,single-channel direction finding for the incident signal can be achieved using the lookup table method.[Results]The feasibility of the proposed method is verified on the basis of the numerical simulation results.Meanwhile,a wideband non-uniform time modulation system available for 2.4 GHz and 5.8 GHz is constructed and its effectiveness demonstrated,with the results showing that the mean of direction finding absolute error is 0.21°and 0.18°respectively.[Conclusions]The proposed method can effectively improve the working bandwidth and has such advantages as a simple structure,low cost,low signal processing complexity and wideband direction finding.