A complete framework for hyperbolic acoustic localization with application to northern bobwhite covey calls

Abstract

Passive monitoring of wildlife has proven to be a highly effective tool in management and conservation. This work describes an end-to-end system for acoustic localization within the context of a specific use case. The system is described in terms of its constituent modules and the functionality of each module, as it relates to the use case of Northern bobwhite (Colinus virginianus) localization, is detailed. First, we address the field deployment of acoustic recorders in terms of optimal configuration, spacing, and number in a manner that is at once utilitarian and mathematically rigorous. Then, we propose novel methods used to automatically detect the calls from recordings, match the detected calls across recordings, and calculate the time difference of arrivals (TDOAs). Finally, a new hyperbolic localization approach is presented that uses the TDOAs to estimate the position of the calls. Each module is formulated within a theoretical framework, implemented numerically in an efficient manner, and shown to compare favorably against existing methods. Moreover, the performance of the complete system is evaluated using field recorded data and the impact of environmental factors such as field relief, vegetation features, and wind speed are illustrated and discussed. We assert and demonstrate that the factor with the most immediate and profound impact on advancing the state of the art in acoustic monitoring of wildlife is open access to high-volume, diverse field data that is accompanied by high-quality ground truth.