基于相关比幅测向的圆阵干涉仪解模糊算法

An Ambiguity Resoling Algorithm by Amplitude-comparison Direction-finding for Uniform Circular Array Interferometer

针对比幅测向精度较低而干涉仪测向相位易模糊这一问题,提出了一种基于多波束比幅测向的圆阵相关干涉仪解模糊改进算法,实现对小型无人机方位的快速估计。首先,根据目标无人机的图传信号特征值建立离线数据库,利用改进的多波束相关比幅法对无人机来波方向进行粗略测量,通过二次插值法对“栅栏效应”造成的估计偏差进行一定修正;然后,将修正后的角度测量值对干涉仪实测相位差进行解模糊;最后,利用无模糊的相位差通过相关运算实现来波方向的精确估计。该算法将相关运算运用在比幅测向中,有效提高了干涉仪解模糊概率。与传统的比幅测向法和干涉仪测向法相比,该算法只需3组天线就能完成测向功能,其测向精度提高至2°以内,并且该算法对天线一致性要求低,实时性高,可实际应用于圆形阵列测向体制,实现对无人机的快速测向。

Focusing on the issue that the amplitude-comparison direction-finding(DF)algorithm has lower accuracy and the interferometer DF algorithm causes phase difference ambiguity easily in direction finding,this paper proposes an improved DF algorithm based on ambiguity resoling by multi-beam amplitude-comparison DF for uniform circular array(UCA)interferometer,which can realize a fast estimation of the direction of the unmanned aerial vehicle(UAV).Firstly,the offline data feature library is established by using the characteristics of the UAV image transmission signal.Then,the improved multi-beam amplitude-comparison DF method is used to roughly measure the direction of the UAV's incoming wave,and the quadratic interpolation method is used to correct the estimation error caused by the“fence effect”.Then the corrected angle is used to eliminate the phase difference ambiguity of the measurements of interferometer.Finally,the corrected measurements is used to calculate the direction of the incoming wave.Application correlation operation in the amplitude-comparison DF method,effectively improves the probability of ambiguity resolving of interferometer.Compared with the traditional amplitude-comparison DF method and the interferometer DF method,the proposed algorithm only needs three sets of antennas to complete the DF,and its accuracy is improved to within 2°,the requirement to antenna consistency is lower and the real-time processing is high.It can be applied to the UCA DF system to realize the all-round rapid DF of the UAV.