THE SENSOR BUS – EASILY INTEGRATE GEOSENSORS AND THE SENSOR WEB
In the past, a multitude of projects have demonstrated the applicability of OGC’s Sensor Web standards. The Sensor Web encapsulates heterogeneous geosensors for web-based discovery, access, tasking, and alerting. Thereby, the geosensors need to be integrated manually with each web service of the Sensor Web. This approach is cumbersome and leads to an extensive integration effort in large scale sensor network systems incorporating many different types of sensors. There is a gap in interoperability between geosensor layer and Sensor Web layer resulting from differing protocol and data structure paradigms. The Sensor Bus, an intermediary layer between geosensors and the Sensor Web, closes this gap and facilitates the integration of sensors and services by establishing a publish/subscribe architecture. A simple bus protocol defines messages to enable the subscription of sensors and services, the publication of sensor observations as well as the submission of sensor tasks. These messages are in a push-based manner transferred via the Sensor Bus. The translation between sensor protocol and bus protocol is performed by particular sensor adapters. Due to the simplicity of the Sensor Bus protocol, these adapters can be created with a low amount of work. This lowers the entry threshold and allows sensor vendors to quickly make their sensors available on the Sensor Web. The Sensor Bus is based on an external communication infrastructure. Different approaches are developed which utilize XMPP, IRC, JMS or Twitter as the underlying technology to realize the communication between sensors and services. The Sensor Bus is published as an open source project (http://www.52north.org/sensorBus) within the 52° North Sensor Web community.
Arne Broering - 52North Initiative for Geospatial Open Source Software