Microprocessor Acoustic Data Buoy

A unique microprocessor controlled digital instrument has been developed for the remote acquisition of underwater acoustic data. The buoy is designed to receive and process long range, low frequency transmissions. Currently it processes complement phase maximal-length shift-register sequences with a carrier frequency of 220 Hz, receives and processes transmissions from nearby moored beacons for phase tracking of buoy motion, and continuously records ambient temperature and time. Matched or inverse filtering of the pseudorandom sequences allows separation of acoustic multipaths for individual study of amplitude and travel time fluctuations. Software control results in a flexible system that is readily reprogrammed to accomodate different transmission parameters and types. The primary advantage of the microprocessor controller is that it enables sophisticated in situ processing and significant power and space economy.