A smart object centric indoor location model for future ubiquitous and grid services

One of the primary requirements for future ubiquitous environment is to exploit location information to provide contextual services. Typical indoor location systems are heavily infra-structured making it difficult to deploy practically in home settings. In this article we propose a lightweight location model utilizing existing physical objects in our environment. Our approach is to use sensor augmented daily life objects surrounding us for extracting location information. Some of these everyday objects are static in nature and have designated location, like a bed in the bedroom, a refrigerator in the kitchen, etc. Utilizing this characteristics, we present "Spreha", a light weight hierarchical location model where static physical objects are used as reference points for identifying mobile objects like a chair, a watch, a lamp, etc. The model is organized in a tree structure representing the containment relationship and is independent of underlying sensing infrastructure. A prototype implementation of the model has been constructed as a pluggable module of a generic middleware using Bluetooth technology. This paper discusses about the design, architecture and findings of the prototype implementation. The implication of such lightweight location model is very important in realizing future environments where ubiquitous services will merge with grid services.