Bioacoust. Res. Program, Cornell Univ., 159 Sapsucker Woods Rd., Ithaca, NY 14850
For over a decade the Cornell Bioacoustics Research Program has been using passive sparse acoustic arrays to locate calling marine mammals in the near field in shallow water, as well as birds and other animals in air. The techniques used have been cross correlation followed by all-pairs hyperbolic geometric positioning, using the simplest propagation model, and iterative nonlinear least-squares error minimization. This talk describes some of our experiences with this process, including the results of calibrated field tests. Applications to whale population censusing and research into the countersinging behavior of song sparrows will be discussed. Many bioacoustic passive array experiments depend on accurate locations at the extremes of the near field, where range is difficult to determine. Analysis techniques for passive near-field arrays have appeared in the literature over the past 50 years. Recently there has been much work devoted to using detailed propagation modeling to improve the accuracy of undersea localization of marine vessels. It is argued that, in the case of animal calls, there are also accuracy improvements to be had from improved signal modeling.