Harmonization of position providers

Hybrid positioning systems have been proposed in order to overcome the limitations of individual location sensing technologies. However, the large differences between the various technologies make integration into a larger system a challenge. This paper proposes a harmonization model which provides different location information sources with a uniform interface. The model creates an abstract representation based on performance criteria and our aim is to provide a basis for the design of location based services. The benefit of our approach is an extensible system that allows for seamless incorporation of new technologies. In addition, it offers a standard format for geographical positions, facilitating higher level treatment of information. To illustrate the usability of the model we implemented a prototype, the Global Positioning Module, which combines several commonly used technologies.