pySAS: Autonomous Solar Tracking System for Surface Water Radiometric Measurements

Abstract

Data recorded by autonomous solar tracking systems onboard ships can be used to validate remote-sensing reflectance observations collected by satellite sensors. Important water quality parameters can also be derived from these data using inverse models. These systems require a mechanical setup that is interfaced with a computer to log radiometric data and to optimally adjust radiometer direction relative to the sun and the platform on which the system is installed to avoid glint. Although solutions are known, no autonomous module compatible with the Sea-Bird Scientific HyperSAS radiometric system is currently available. Here, we present an open-source system, pySAS, that can be constructed for less than $5,000 (excluding radiometers). The pySAS uses two GPS units for orienting the radiometers to avoid effects of the platform’s magnetic field. The system can be modified for use with other radiometers.