Interesting (?) Applications for Acomms

Underwater acoustic communications (acomms) technology and capability have reached somewhat of an equivalence with the mobile cell phones of a decade ago. Commercial modems are available from more than a few vendors, but they mainly provide purely an acomms function. At the academic level technology development focuses on increased throughput (or data rate), and/or on the development of undersea networks. While we at Teledyne Benthos actively pursue both of these enhancements, our emphasis is to design for many auxiliary capabilities that, while not explicitly communications functions, rely on the communications capabilities and computing infrastructure of the modem. We are pursuing the “smart” phone approach wherein communications is but one capability of the device. The internal structure of the Telesonar modem is based on a file-sharing system which supports all aspects of the modem: acoustic and/or sensor (digital) data storage, stored wavefiles (for experimental transmissions), and algorithm implementations. In particular, it supports an SD-card data storage system, currently providing 64 Gbyte of storage. As an example, we can stream full bandwidth acoustic data, or serial data from an attached sensor in real-time to the SD card. Our form of storage is known to any remote modem such that any file or files can be uploaded and acoustically transmitted. The remote modem may also query any aspect of the stored data – the amount of storage used, the number of files stored, etc., without impact of any kind on the “modem” operations. The combination of arbitrary waveform transmission (from stored files) and acoustic data recording was recently used to demonstrate the ability of a specialized waveform for use in highly reverberant and physically constricted environments. This combination of capabilities enabled the complete design, testing, and data analysis to be completed in under one week without the necessity of embedded programming within the modem DSP.