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RAR: Real-Time Acoustic Ranging in Underwater Sensor Networks

As a core component of underwater localization, accurate acoustic ranging is quite challenging because of the harsh characteristics of underwater environments (e.g., refraction and reflection). To enhance ranging accuracy, ranging schemes employing a ray tracing model and a sound speed profile have been proposed; however, the existing schemes require numerous ray tracing iterations to perform ranging estimation within a certain range of accuracy. This renders the solutions that they generate impractical for real-time localization. In this letter, we propose a novel ranging scheme called real-time acoustic ranging (RAR). To reduce computational overhead while maintaining reliable accuracy, RAR exploits the property of ray pattern locality, whereby spatially proximate rays exhibit similar patterns. The results revealed that RAR can ensure a better tradeoff between accuracy and computational overhead than a state-of-the-art solution.