Robust Adaptive Broadband Beaforming
Date Issued
2004
Date
2004
Author(s)
Chang, Chao-Yuan
DOI
zh-TW
Abstract
A broadband multiple beamformer can receive signals over a wide frequency band and simultaneously suppress the interference signals and background noise to achieve high signal to interference plus noise ratio (SINR). However, the broadband multiple beamformer’s output SINR deteriorates severely so that it can’t receive the desired broadband signals when there is a mismatch between the steering matrix and the direction matrix of the desired signals. Therefore, this thesis presents a robust algorithm for the broadband multiple beamforming technique based on the fact that the projection magnitude of a steering vector onto noise subspace basis is zero when the steering vector is equal to the direction vector of the desired narrowband signal in narrowband array beamforming. Our aim is to obtain a modified steering matrix of the desired broadband signals through an optimization procedure to improve the broadband multiple beamformer’s output SINR. We propose a method that minimizes the sum of the projection magnitude of each column of the steering matrix onto noise subspace basis and a constraint related to the negative log-likelihood function of the steering matrix error. The modified steering matrix can be calculated using an iterative procedure by the gradient method. Finally, the robustness in performance of our proposed method is demonstrated by computer simulations under pointing error and positional error situations. We demonstrate that our proposed method is highly robust in pointing error and positional error. The modified broadband beamformer’s output SINR can approach that one under ideal situation by our proposed method
Subjects
寬頻
波束成型技術
陣列信號處理
array signal processing
robust
beamforming
Type
thesis
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