考慮實際環境的波束成型技術用於傳統陣列天線及多輸出多輸入雷達系統

Robust Beamforming under Actual Environments for Conventional Antenna Arrays and Multi-input Multi-output Radar Systems

李坤哲(Kun-Che Lee)

指導教授 ： 李枝宏

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201803411

摘要

本篇論文中，我們將討論如何設計一個波束型成器，能在實際環境中運作。
在傳統的均勻線性天線陣列(Uniform Linear Array, ULA)中，有別於MVDR (Minimum Variance Distortionless Respponse)，我們實驗室所設計的MGSC(Modified Generalized Sidelobe Canceller)，能夠有效處理欲接受訊號的角度誤差，以此為出發點，發展出能夠同時對抗天線交互耦合(Mutual Coupling)現象的MCCE-MGSC(Mutual Coupling Coefficient Estimation MGSC)，接著改善有限資料點的問題，而發展出ESB-MCCE-MGSC(Eigenspace-Based MCCE-MGSC)。
在均勻圓形天線陣列(Uniform Circular Array, UCA)，為了能夠有效處理欲接受訊號的角度誤差，我們同樣採用MGSC的做法，將其到用至UCA的架構，再仿造原發明者提出的兩種延伸的MGSC-分別為ESB-MGSC與RCMV-MGSC，也將這兩種想法導入均勻圓形陣列。
針對MIMO Radar(Multi-input Multi-output Radar)架構的波束型成技術，我們將MGSC套用於此架構，並參考現有文獻中的PRMVB(Proposed Robust Minimum Variance Beamformer)與ADL(Automatic Diagonal Loading)。另外也將FDDL(Fully Data-Dependent Loading)與ESB(Eigenspace-Based)套用在MIMO Radar系統中。嘗試將上述的各種技術搭配組合，比較在各種實際環境下的優劣好壞。
考慮到多重路徑問題所造成的同調干擾，我們參考空間平均法(Spatial Smoothing)，並提出VWS(Virtual Windowing Smoothing)專門用於MIMO Radar系統中，並以EstFAWS(Estimation Full Array Windowing Smoothing)恢復因VWS失去的天線效能。受VWS啟發，我們可以將訊號針對發射端與接收端重複處理，稱為分離式結構(Separate Structure) ，搭配MGSC與ESB將效能大幅提高，並且能在實際環境下正常工作。

關鍵字

強健性波束型成 ； 指引向量誤差 ； 交互耦合現象 ； 多輸入多輸出雷達波束型成 ； 同調干擾

並列摘要

In this thesis, we will introduce how to design a beamformer that can work under an actual environment.
For traditional uniform linear array (ULA), MGSC (Modified Generalized Sidelobe Canceller), unlike MVDR (Minimum Variance Distortionless Respponse), can effectively handle the angular error of the desired signal. Based on this beamformer, we design the MCCE-MGSC (Mutual Coupling Coefficient Estimation MGSC) which can simultaneously resist the mutual coupling phenomenon. Considering the problem of finite samples, we combine ESB (Eigenspace- Based) beamformer with MCCE-MGSC to suppress the problem.
For uniform circular array (UCA), we still use MGSC and apply it to the UCA structure in order to effectively handle the angular error of the desired signal. Then we imitate two better methods (ESB-MGSC and RCMV-MGSC) proposed by the original inventors and also apply them to UCA structure.
For the beamforming technology of MIMO Radar (Multi-input Multi-output Radar) system, we refer to PRMVB (Proposed Robust Minimum Variance Beamformer) and ADL (Automatic Diagonal Loading) and apply them and MGSC to this system. In addition, FDDL (Fully Data-Dependent Loading) and ESB (Eigenspace-Based) are also applied in the MIMO Radar system. Try to combine the above various technologies to compare the advantages and disadvantages under various actual environments.
Considering the coherent interference caused by the multipath problem, we propose a method called VWS (Virtual Windowing Smoothing) to against it, specifically for the MIMO Radar system.Furthermore, we will use EstFAWS (Estimation Full Array Windowing Smoothing) to recover the antenna performance lost due to VWS. Inspired by VWS, we will process the signal vectors based on transmitter and receiver respectively, called separate structure. Based on this structure with MGSC and ESB, the performance is greatly improved and can work well under the actual environments.

並列關鍵字

robust beamforming ； steering vector error ； mutual coupling ； MIMO radar beamforming ； coherent interference

參考文獻

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[5]Bin Liao, “Adaptive beamforming for uniform linear arrays with unknown mutual coupling,” IEEE Antennas and Wireless Propagation Letters, vol.11, no.2, pp.464-467, Jan.2012.