Finding the right cross-correlation peak for locating sounds in multipath environments with a fourth-moment function

To locate calling animals in reverberant environments from recordings on wi dely separated receivers, a fourth-moment "Augmented-Template Correlation F unction" (ATCF) helps identify which of many peaks in each cross-correlatio n function is that corresponding to the difference in travel times for the first arrivals (reference-lag). This peak may not be the largest. The ATCF, by providing an approximate correlation between auto- and cross-correlatio n functions, can be orders of magnitude more efficient in selecting the ref erence-lag than the alternative of randomly selecting peaks. The ATCF's eff icacy increases with the number of paths and their signal-to-noise ratios. (C) 2000 Acoustical Society of America. [S0001-4966(00)00909-7].