中文摘要：

应用自适应滤波方法可以估计未知源信号的观察信号间的时延。但是只有知道观察信号的信噪比或者其中源信号分量的自相关函数或功率，才能确定时延估计的方差。本文根据被动检测时延估计的信号模型和自适应滤波原理分析指出，采用自适应滤波结果直接计算的相关分量的自相关函数及功率是一个有偏估计。应用自适用滤波器参数，可以得到一个常数修正因子，修正该有偏估计，得到自相关函数的近似无偏估计。不同条件下的估计实例表明，通过修正显著提高了信号功率估计的准确性。

英文摘要：

The time delay between the observed signals contained an unknown source can be estimated by adaptive filters. By analyzing the signal models for time delay estimation in passive detection and referring to the principle of adaptive filtering, it is pointed that the power or autocorrelation estimate of the components related to the source, if which straightly descends from output of the adaptive filter, is biased. A constant modification factor is derived to obtain the approximately unbiased estimate. The estimated results under various specifications demonstrate that the modification has significantly improved the accuracy of power estimates.