Patent ID: 7321849

Claim:
A computer-implemented process for providing a geometric model database for use in a ubiquitous computing environment to respond to queries about the environment's geometric state, comprising: an accepting step for accepting information about the geometric state of the environment; a building step for building a geometric model database of the environment based on an initial input of said information, said building step comprising, an establishing step for establishing a set of entities that are of interest in the environment, each entity of which is represented by at least a coordinate frame unique to that entity and an extent, wherein said extent defines one of (i) the physical size of the entity, or (ii) the service region of the entity, a characterizing step for characterizing the location of each entity in the environment in terms of the coordinate frame of at least one other entity, rather than in terms of a coordinate frame common to all entities, using a measurement defining the entity's relationship to at least one of said other entities, wherein said measurement comprises the position and orientation of each other entity's coordinate frame origin in terms of the coordinate frame of the entity under consideration and a spatial uncertainty estimate which is indicative of the accuracy of the method used to obtain the measurement, and wherein each measurement is provided to the geometric model database by an external source and more than one measurement defining an entity's relationship to another entity may be provided by separate external sources, and a combining step for combining said measurements using their relative uncertainties as weights whenever more than one measurement defining an entity's relationship to another entity is received; a maintaining step for maintaining the geometric model database by modifying it based on the input of updated information about the geometric state of the environment; and a responding step for responding to queries concerning the geometric relationships between entities in the environment using the geometric model database.