在二維天線陣列雙基地台多輸入多輸出架構下使用 ESPRIT 與共變異數矩陣重建進行目標物角度估計

Abstract

本篇碩士論文主要探討如何在2-D URA天線陣列下進行雷達天線陣列的角度估計，會將問題延伸到雙基地台多重輸入多重輸出(Bisatic MIMO)上，並解決多重誤差對角度估計造成的影響。多重誤差包括未知天線耦合誤差、同調訊號環境、天線耦合誤差+同調訊號環境。

相較於使用一維均勻天線陣列，因為二維天線陣列能夠偵測物體的仰角與方位角，能更精確估測出物體在空間中的位置，因此決定將二維天線陣列當作本論文的架構之一。

本論文前段將會討論EPSRIT角度估計演算法(Estimation of Signal Parameters via Rotational Invariant Techniques)。最後，多重非理想環境將會加入討論，並解決這些非理想環境對角度估計在2-D URA下的影響。

為了解決上述的多重非理想環境，首先使用依據未知天線耦合距離與天線陣列大小所產生的選取矩陣，解決未知天線耦合對2-D URA角度估計所帶來的影響。再者，利用空間平滑(Spatial Smoothing)與共變異數矩陣重建(Covariance Matrix Reconstruction)解決同調訊號環境(Coherent Signals)對2-D URA角度估計所帶來的影響。最後，將會探討如何在誤差環境為天線耦合與同調訊號雙重誤差環境下，解決誤差環境對2-D URA角度估計帶來的誤差。

The goal of this thesis is to explore the angle estimation problems of arrivals for Bistatic MIMO radar with two-dimensional (2-D) uniform rectangular array (URA) deployed at its transmitter and receiver. The proposed method deals with multiple mismatches, including mutual coupling between array sensors, coherent signals, and mutual coupling plus coherent signals. Compared to one-dimensional uniform linear arrays (1-D ULAs), 2-D URAs have the advantages of estimating the azimuth and elevation of targets simultaneously and producing a more precise estimation. Due to the higher complexity required by employing the conventional MUSIC, we utilize the ESPRIT algorithm for finding the angles of the targets in the presence of Coherent signals, mutual coupling, and coherent signals plus mutual coupling. To deal with the multiple mismatches mentioned above, we present several specific selection operations working on the signal subspace of the received array data in conjunction with spatial smoothing scheme and covariance matrix reconstruction. Computer simulation results are provided for confirmation and comparison.