Open-source technology offers expansion of satellite validation capability

Observing water colour (reflectance) allows researchers to assess the presence of phytoplankton, suspended solids and dissolved organic matter in inland, coastal and ocean waters. The automated, open-source So-Rad (solar-tracking radiometry) platform significantly lowers the cost of collecting ground truth to validate these observations made by satellites.

One of the best ways to increase the volume of useful water-leaving reflectance observations is to mount radiometers on a turning platform. Thus far only experimental and closed-source commercial solutions existed, neither of which were sufficient to achieve the ambition of delivering continuous, quality-controlled satellite validation data around the world.

With the So-Rad, PML provides owners of commercially available radiometers the possibility to upgrade fixed-angle systems. A step-by-step build guide is now available through the So-Rad page on the MONOCLE website. The build guide includes hardware and software components including CAD diagrams for both electronics and machining. All materials are published under a Creative Commons Attribution-Non-Commercial license.

Some key features of the So-Rad include:

• Low power consumption (15W)
• Viewing angle adjustment for solar position and platform heading, suitable for ships and (large) buoys
• Tilt/pitch/roll monitoring
• Local data buffering for fully autonomous operation
• Configurable operating range for viewing angle, solar elevation, and measurement intervals: no need to collect data under suboptimal conditions
• Control software written in Python 3, modular design to extend e.g. additional sensor support
• Local (WiFi) and remote (LTE) monitoring