Evaluating Sensor Observation Service implementations

The Open Geospatial Consortium (OGC) Sensor Web Enablement initiative and is showing signs of maturity. One such sign is the development of software implementations of given OGC standards. We are aware of four implementations of the Sensor Observation Service (SOS) specification in various stages of development. We consider this quartet of implementations in the context of three observation scenarios and assess for each implementation the software architecture, perceived ease and flexibility of deployment, completeness of implementation against the standard, and some preliminary discussions of performance. Since they are integral to a SOS, we also comment on O & M (Observations and Measurements) and SensorML implementation. We discuss the relative advantages and disadvantages of each implementation and point to challenges we experienced in working with these various Sensor Observation Services.