基于同态滤波的MLS抗多径测角算法

针对微波着陆系统存在多径干扰引起测角误差的问题,研究了多径干扰的短时、相关、对称、卷积等特性,提出一种基于同态滤波的抗多径测角算法.建立了基于双对称性的信号模型,然后将卷积特征系统转换为线性系统,最后在混合信号中提取信息,实现了“往”“返”脉冲时差的精确测量.仿真表明,在“往”“返”脉冲接收信号存在多径干扰时,该算法能有效地降低多径干扰对测角精度的影响;当算法满足适用条件时,与常规测角算法相比精度提高了一个数量级.

MLS anti-multipath angle measuring algorithm based on homomorphic filter

In microwave landing system (MLS),multipath interference effect may lead to error in angle measurement. To solve this problem, the short-time, correlation, symmetry and convolution characteristics of multipath interference are addressed, and an anti-multipath angle measurement algorithm is presented based on homomorphic filtering. In detail a signal model based on bi-symmetric property is established, then its convolution eigensystem is converted to linear system, and finally the information can be extracted in the mixed signals, with precise measurement of pulse time delay in sending and receiving realized. The simulation reveals that the algorithm decreases the influence on angle measurement precision from multipath interference existed in receiving pulse signals to and from the target. When the algorithm meets the availability condition, its precision improves by an order of magnitude, compared with that of normal angle measurement methods.