Custom Acoustics Instruments

Since 1983, we have continuously participated in the development and application of active and passive acoustic technology to oceanographic and flow measurement problems. Acoustic technologies, as applied to oceanography, can be thought of as a form of underwater radar. Like radar in the atmosphere, underwater acoustic techniques can measure the properties of large volumes of water far more efficiently than traditional point-measuring instruments. Moreover, underwater acoustics can reach into areas inaccessible to older technologies. Active acoustic instruments generate acoustic signals as a means of exploring the aquatic environment, collecting information non-intrusively. Instruments such as ASL's Ice Profiler™, Wave Profiler ™, Multifrequency Acoustic Water Column Profiler ™, Acoustic Scintillation Flow Meter™. are examples of active acoustic instruments, each providing acoustic monitoring of variations in their transmitted sound beams. Passive acoustic instruments use ambient sound to characterize important aspects of the underwater environment. Noise generated by natural phenomena can be used to measure key environmental behaviors. In open water, our company has been among those pioneering the use of the sub-surface noise recorders of WOTAN (Wind Observation Through Acoustic Noise) in monitoring marine wind-speeds. Passive signal recording in ice-covered waters has been used by ASL to study sea-ice dynamics for potential application to ice forecasting.   Feasibility studies We conduct feasibility studies in the applicability of acoustic techniques, often incorporating these into conceptual models for the custom development and testing of instrumentation, including the modification of existing instruments. We provide data collection and analysis services, from direct transcription to sophisticated analyses directed at scientific research issues. We maintain a library of signal processing and computing procedures, and have a set of propagation models to simulate acoustic propagation in a variety of underwater environments. We are frequently called upon to determine the applicability of acoustic techniques to a given oceanographic or flow measurement problem. Such feasibility studies often use existing or estimated data in conjunction with computer-based simulation techniques. Results from such studies are incorporated into conceptual models for detailed custom instrument development and testing. New Instrumentation We provide customized design and building services for new instrumentation and software. We will also, where feasible, modify existing instruments or software to meet client needs in an economical manner. A set of propagation models which employ standard ray tracing and parabolic equation solution techniques are used to simulate acoustic propagation in a variety of underwater environments.