In Situ Depolarization, Attenuation, and Scattering Sensor

NASA is seeking a sensor that provides in situ measurements of ocean particulate backscatter, depolarization, beam attenuation, and diffuse attenuation coefficients relevant for combined ocean-atmosphere active remote sensing. To address this need, Intellisense Systems, Inc. (Intellisense) proposes to develop an In Situ Depolarization, Attenuation, and Scattering (IDEAS) sensor. IDEAS is submersible to gt;300 m and innovatively incorporates a beam attenuation and depolarization sensing subsystem and a backscattering sensing subsystem in a single unit, along with a depth sensor. The first subsystem innovatively measures the inherent losses and depolarization for linearly and circularly polarized beams as a function of depth and uses this data to calculate the diffuse attenuation coefficients based on a user-defined light field. The second subsystem determines the scattering for angles gt;170 deg with an angular resolution of lt;1 deg and innovatively calculates the full scattering matrix using polarization-sensitive detectors. IDEAS operates at wavelengths ranging from 355 nm to 1064 nm and is designed for unattended operation. In Phase I, Intellisense will develop a system that measures beam attenuation, depolarization, and backscattering by particulates at multiple wavelengths in a laboratory environment and calculates the diffuse attenuation coefficients, thus clearing the way for Phase II. In Phase II, Intellisense will develop a prototype that is ocean-submersible to 300 m or deeper and that will provide in situ measurements of ocean particulate backscatter, depolarization, beam attenuation, and diffuse attenuation coefficients relevant for combined ocean-atmosphere active remote sensing at 355, 473, 486, 532, and 1064 nm. The backscattering sensing subsystem will provide measurements from 170 deg to 180 deg scattering angles with an angular resolution of lt;1 deg. Intellisense will deliver the prototype to NASA, including all necessary hardware and software.