具多重限制之最小平方法空間濾波器設計

Abstract

本論文提出一種Multiple Constraint Adaptive Frost Beamformer演算法，本演算法乃是藉由整合傳統Frost Beamformer演算法以及Fractional Delay Filter設計技術而形成之新型空間濾波器。本篇論文可分為三大部分，第一部分略述基本之陣列訊號處理特性以及相關之發展。第二部分則介紹如何利用Adaptive Frost Beamformer以及Fractional Delay Filter相關技術設計出本篇論文所提出之Multiple Constraint Adaptive Frost Beamformer演算法。而第三部分則為結果分析，首先針對本演算法之相關限制加以探討，接著利用模擬結果說明此演算法之效能，並與傳統Adaptive Frost Beamformer作比較。本演算法之優點為能夠防止Coherent Source對Frost Beamformer所造成之Source Signal Cancellation效應。除此之外，此演算法亦可應用於Multiple Beam、Multiple Null之設計，使得Adaptive Frost Beamformer之相關應用能夠更有彈性。

In this thesis, a multiple constraint LMS beamformer algorithm is proposed for wideband beam steering. The algorithm combines the traditional Frost beamformer algorithm and optimal fractional delay filter design technique so that multiple beams or nulls can be formed in arbitrarily assigned directions. Because of the null constraint, the proposed algorithm can avoid the desired signal cancellation effect caused by coherent sources in the Frost beamformer algorithm. This thesis is divided into three parts. In the first part, a brief introduction to array signal processing is presented. In the second part, the proposed algorithm is analyzed and the limitation is discussed. Simulations are conducted and the performance is compared with Frost beamformer in the third part. It is shown that the spatial filtering result is much better than Frost Beamformer when coherent sources appear in received signals.