適應性寬頻干擾消除波束合成法之實驗研究

Abstract

在本報告中，吾人針對海底水聽器陣列訊號之頻域及空域特性，嘗試利用 高解析力之空間頻譜估計法，如分頻結構的CSDM-MVDR 法及聚焦寬頻結構 STMV法等，進行寬頻帶水底聲源之定位。在定出聲源之方位後，吾人利用 適應性寬頻波束合成法，如聚焦寬頻結搆的CSM-MVDR及吾人所提出的 IDCSM-MVDR波束合成法，進行目標訊號之擷取與干擾消除。經由電腦模擬 及真實聲納陣列資料之分析，吾人驗證：結合STMV及IDCSM-MVDR為一可行 之處理方法。與傳統之delay-and-sum 定位及波束合成比較，此IDCSM- MVDR提供了較佳之解析度及干擾消除能力。 In this thesis, we propose the use of high-resolution spatial spectrum estimators, such as cross-spectral density matrix (CSDM) MVDR and steered covariance matrix MVDR (STMV), for localizing wideband underwater acoustical sources with a hydrophone array. These methods are employed in accordance with the frequency and spatial domain properties of the array signals. We also propose the use of wideband adaptive beamformers, such as coherent signal-subspace method based MVDR (CSM-MVDR) and the interpolated Duvall CSM-MVDR (IDCSM-MVDR) beamformers, for desired signal acquisition and interference cancellation. We confirm, via computer simulations and real data analyses, that the IDCSM-MVDR method working in conjunction with STMV is an appropriate way of implementation. Compared with the conventional delay-and-sum method, the proposed one exhibits better resolution and interference rejection capability.