- 作者: 陳巽璋; 林士能
- 作者服務機構: 中山大學電機工程學系
- 中文摘要:
估測及追?兩個分開的接收器間的時間延遲(time delay),已被廣泛的應用在各種工程問題上。例如在聲納系統中,
藉由時間延遲的估測,我們可以獲知聲源的位置。
在本論文中,我們提出以直接估測延遲公式(direct delay estimation formula)結合三階累積(third-order cumulant)適應
性參數趨近法來進一步的改善估測品質。因為直接估測公式是一種簡單且快速有效的時間延遲估測法,它不需要傳統的
方法所用的內插法公式(interpolation formula)或做查表法(look-up table)去估測非整數的時間延遲,因此所需的電腦計算
時間減少甚多。而且三階累積法又能夠抑制高斯(Gaussian)雜訊。所以面對於環境如非高斯(non-Gaussian)信號源,而附
加性的(additive)高斯雜訊在兩個接收器上不管是相關性的(correlated)或非相關性的(uncorrelated),所提的方法在信號雜
訊比(SNR)為5dB或0dB下都具有非常精確的估測品質比較於一階動差(first-order moment)適應性參數趨近法。
為了進一步研究直接估測延遲公式的優越性,我們也應用它到二階累積(second-order cumulant)適應性參數趨近
法做時間延遲估測。其結果除了在相關性雜訊下的信號雜訊比為0dB情況外,其餘情況皆和上述所提的方法一樣具有精
確的估測品質。
在論文裡,我們以靜止(stationary)和非靜止(nonstationary)的時間延遲環境來驗證所提方法的優越性及品質優於沒有
使用直接估測延遲公式的傳統方法。
. - 英文摘要: The problem of time delay estimation (TDE) between two spatially separated sensors is very attractive invarious fields. For example, in a sonar system, the information of time delay can be used to localize the radiatingsource. In this paper, the direct delay estimation formula along with the adaptive third-order cumulant (TOC) methodis presented. The advantage of using the direct delay estimation formula is that, for extracting the non-integertime delay, the conventional methods, such as the look-up table and interpolation formula, are not required, sothe computational requirement can be reduced dramatically. Moreover, the high-order cumulant methods can suppressGaussian noise, especially when the desired signals are non-Gaussian. To evaluate the performance of the presented method, a computer simulation has been carried out for stationaryand nonstationary time delay environments. To further investigate the merits of the direct delay estimation formula,we also apply it to the adaptive second-order cumulant (SOC) method for TDE. The cases where the additivenoises in both sensors are to be correlated or uncorrelated with each other are considered. From simulation results with the signal-to-noise ratio (SNR) set to be 5 dB and 0 dB, we found that theimprovement was significant compared to the results without using the direct delay estimation formula method.Moreover, the results of the TOC and SOC methods have more accurate estimation compared to the first momentmethod with the direct delay estimation formula. This is also true for the case where noises in both sensors arehighly correlated with each other when the SNR is 5dB or higher. However, for SNR of 0 dB, only the methodwith TOC showed improvement when the direct delay estimation formula was employed.
- 中文關鍵字: adaptive; nonstationary; time delay; cumulants; correlated noise
- 英文關鍵字: --