An intelligent space location identification system based on passive RFID tags

The development of context-aware control for smart space applications becomes popular recently, in which radio frequency identification (RFID) plays an important role. For an indoor context-aware smart space system, RFID tags and readers are utilized to locate object coordinates, cf. GPS utilizes GNSS for capture outdoor location information. Previous researches proposed to deploy regularly spaced reference tags, based on which the space location of target object tag can be estimated. Due to tag signal collision and received signal errors, the estimation accuracy is limited. We propose to utilize more than one RFID readers and control the reading power to eliminate estimation error. Passive tags that are cost effective are deployed for dense tag grid, e.g., for high accuracy location estimation. Experiments show that the proposed method can significantly reduce the estimation error from 69 cm to be under 15 cm. This RFID-based object location system can be applied to help people to locate personal belongings. In addition, a video surveillance system can be integrated with the object location method to provide context-awareness service.