From heterogeneous marine sensors to sensor web: (near) real-time open data access adopting OGC sensor web enablement standards.

Sensor engineering is continuously evolving as devices become cheaper, smaller, more intelligent, and more efficient. Today, oceanographic sensors aim at monitoring marine processes by means of physical, chemical, and biological variables, and use different data formats, units, parameters, resolutions, data quality standards, and protocols. Therefore, integration and interoperability at European level represent a challenge.To cope with this challenge, the Sensor Web Enablement (SWE) standards, developed by the Open Geospatial Consortium (OGC), are a good solution, as they ensure interoperability and long-term archiving of data series with complete information for all devices.The interoperability allows integrating information from different sources or pre-existing architectures, such as those developed in the SANY project (http://www.opengeospatial.org/ogc/regions/SANY) or by the US Integrated Ocean Observing System (https://github.com/ioos).In this paper, we illustrate the real-time data management system, developed by the Italian National Oceanographic Data Centre (NODC) at the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, OGS in Trieste – Italy, designed to share data acquired by a large number of heterogeneous observing platforms. This system adopts Observations and Measurements (O&M) and Sensor Model Language (SensorML) as data and metadata formats, as well as the Sensor Observation Service (SOS) released by the 52°North as server and Web client for open data access.The work done shows that the choice to manage real-time data using OGC Sensor Web Enablement (SWE) standards can be considered a valid solution with pros and cons. Nevertheless, in the future, the SWE community will grow, and with it, the number of applications to manage SWE standards to simplify their adoption.