Web services: Design choices for space ground system integration

The primary role of a ground system in the design of a space ground network is to exchange information between the space fleet and the end users. In order to maintain secure, reliable communications and provide situational awareness, a ground system needs to choreograph services between heterogeneous interfaces of various key elements in the ground system architecture. The choice of Service Oriented Architecture and Web Services provides a cost effective and scalable solution to integrate disparate software elements of the ground system. The two major concepts in web service technology are SOAP and REST. While SOAP is a protocol to transfer information between two end points, REST principles concentrate on representing resource state information using resource identifiers. The paper discusses merits and de-merits of each approach in the integration of a space ground system's heterogeneous interfaces. The paper starts with the large grain description of a typical space ground system, followed by a discussion of SOAP and REST principles. A comparison of SOAP and REST based approaches in the design and integration of a ground system is discussed. Finally the paper concludes with a discussion of recent trends in the techniques of web services.