微波着陆系统波束指向误差仿真分析

Emulation and Analysis of Beam Pointing Error in Microwave Landing System

为了提高微波着陆系统地面设备的角度引导精度,基于微波线性相控阵天线理论,分析了地面角度引导设备产生相控阵天线波束指向误差的主要原因——数字移相器的量化误差,并进行了不同量化阶数下的舍尾法馈相误差分析及仿真。为了寻求系统精度与设备成本的折衷,在采用四位移相器的条件下比较了随机馈相法与传统的舍尾馈相法的波束指向误差,仿真分析了相位误差均值为零法与适当随机相位量化法对波束指向误差的影响;这两种方法消除了周期性误差峰值,提高了相控阵天线的波束指向精度,其中适当随机相位量化法效果更佳;说明了采用随机馈相法能够有效减小因数字式移相器相位量化误差导致的波束指向误差,使系统精度明显提高。

In order to improve the accuracy of ground angle guiding equipment in Microwave Landing System, based on microwave linear phased array antenna theory, the main factors of causing phased array antenna beam to point error and the errors produced by floor phase feeding in different Quantization steps are analyzed. Beam pointing errors obtained from floor phase feeding and from randomizing phase feeding by using 4 - bit Phase Shifter are compared. Through simulation, two randomizing phase feeding methods are particularly discussed and analyzed. The periodic error is eliminated by using these two methods and consequently the phased array antenna beam pointing accuracy is improved especially by Appropriate Random Phase Quantization. The simulation results indicate that beam pointing error is significantly decreased and the location accuracy is greatly improved.