But there are two greatest limitations of this method : the scale at which the continuum approximation is justified can be difficult to quantify and the process of spatial averaging restricts model predictions to scales greater than or equal to that of the representative elemental volume ( rev ) 前一種模型為連續(xù)體模型,已經(jīng)是一種相對成熟的方法,但對于不存在rev或rev很大的裂隙巖體,可能會帶來不合理或不正確的結(jié)果。
Broadband source location method is investigated by using signal-phase-matching principle, and simulations and experiments are carried out to show the validity of the method; two high resolution algorithms of broadband signals are proposed, which are the dft interpolation algorithm and the frequency invariant beam space algorithm . the proposed algorithms have no requirement for prior information of source locations, so the results of doa estimation can be unbiased; a method of temporal-spatial averaging, which can improve the performance of doa estimation for uniform linear arrays, is given . this method can be applied in the most narrowband or broadband eigen-structure based high resolution algorithms 提出了利用信號相位匹配法的寬帶信號方位估計方法并從仿真和實驗兩方面對其進行了驗證;提出了基于dft插值的和基于頻率不變響應波束域的兩種寬帶信號高分辨方位估計算法,這兩種方法在進行方位估計時均不需要進行方位預估,從而避免了因角度預估可能帶來的估計偏差;最后提出了一種提高均勻線列陣方位估計性能的時空平均法,該方法可適用于多數(shù)窄帶或?qū)拵У奶卣鹘Y(jié)構(gòu)類高分辨方位估計算法中。