Towards an open geospatial service architecture supporting heterogeneous earth observation missions

Heterogeneous Earth Observation missions pose the problem that each of them offers its own way and technology of how to search for and access to mission results such as Earth observation datasets. Typically, these tasks are provided by ground segment software services which may be called through corresponding interfaces by client geospatial software applications. This paper presents the design and the architecture of the Heterogeneous Mission Accessibility (HMA) which is an interoperability initiative of the European/Canadian Ground Segment Coordination Body. The final objective of HMA is to leverage the idea of a service-oriented architectural style. This means, that the individual ground segment systems shall be loosely-coupled by means of an HMA Service Network. The paper is an excerpt of the comprehensive "HMA cookbook" to be published soon by the European Space Agency (ESA). It describes the HMA approach for user authentication and authorization based upon standard Web services and the discovery of, the access to and the presentation of datasets by means of Open Geospatial Consortium (OGC) standards. It is outlined how the feasibility analysis of sensor observation tasks and the ordering of products may be expressed by the service and information models of the OGC Sensor Web Enablement initiative. The paper concludes with a discussion about the follow-on research topic of service-oriented design of Earth observation applications.