A fast algorithm for computing doppler introduced by sea surface gravity waves.

Abstract

The technical advances in phase coherent underwater acoustic communications and the increasing availability of relatively inexpensive commercial modems have created a renewed interest in utilizing sound channel models for predicting modem performance. While accurate channel models already exist, their usefulness for modeling extensive “what‐if” scenarios is limited by the computational resources required. Acoustic field models based on raytracing methods are a fast and efficient approach to sound channel modeling. They readily lend themselves to estimating the impulse response or time arrival structure of a hypothetical sound channel. The computed impulse response can then be convolved with the waveform transmitted by the modem to obtain an estimate of the timeseries observed at a hypothetical receiver. The existing models for addressing the Doppler effects introduced by sea surface gravity waves into the receiver timeseries are accurate, but relatively resource hungry. A fast algorithm for modeling Doppler based on simple postprocessing of the eigenrays computed by the raytracing based field model will be presented.