As the Navy continues to pursue development of advanced underwater imaging and optical communications systems, the need for state-of-the-art underwater optical imaging and light transmission models, and the optical oceanographic data to support them, is dramatically increasing. Today the Navy must use non-government activities to obtain key oceanographic data, such as optical volume scattering, needed to calculate the point spread function and backscattered light levels in underwater optical system design. Global Associates, Ltd., (Global) proposes in this Phase II effort to design, prototype, and demonstrate a compact polar (i.e., angular) nephelometer (beta-c meter) capable of providing both high resolution optical volume scattering data between 0.1o and 179.9o, and the beam attenuation coefficient for several wavelengths. The only marginally similar instrument, the General Angle Scattering Meter (GASM), can be used only at night under low ambient light levels. Global's design provides a noise rejection capability which will allow use day or night, thus reducing the cost and complexity of obtaining these measurements, and which utilizes acquisition. No existing instrument can determine the optical volume scattering function in both the large angle scattering region, 10o-170o, and the small forward and backscatter directions (0.1o-1.5o and 178.5o-179.9o in 0.1o degree increments) as will Global's. In addition, the proposed instrument will be controlled by a personal computer, which not only provides an efficient user interface, but also allows user flexibility in data storage, manipulation,and display capabilities.
