Pair-wise Spectrogram Processing Used to Track a Sperm Whale

We developed a model-based localization method called pair-wise spectrogram (PWS) processing to track marine mammals using widely spaced hydrophone arrays [Nosal & Frazer, IEEE J. Ocean. Eng., in press]. Here we use PWS to track the sperm whale from the dataset provided for the 2005 Workshop on detection and localization of marine mammals using passive acoustics (Monaco). This dataset provides a good opportunity to validate and explore the properties of the PWS processor. We demonstrate the relationship between pair-wise processing and a time-of-arrival method for a simple case. We also show how varying the size of windows used to create spectrograms optimizes the tradeoff between processor resolution and robustness, and how these parameters can be adjusted according to grid spacing. PWS position estimates are within tens of meters of those obtained using a careful time-of-arrival method applied to individual clicks.