Implementation of distributed sensor network for intelligent space

In this paper, we introduce a basic framework of Intelligent Space (iSpace) and automated calibration of the distributed sensors using mobile robots. iSpace is a room or area where many intelligent sensors and actuators are distributed and networked. In iSpace, the embedded sensors can monitor the whole environment by communicating with each other through the network. Based on the observed information, the actuators provide informative and physical services to users. In order to implement such a system, a basic framework which realizes a close cooperation among distributed devices has to be considered. We propose a layered structure which consists of four layers - the sensor node layer, the basic information sever layer, the application layer and the actuator layer. The structure makes it possible to fuse information extracted by each sensor node effectively and provides flexibility and scalability to the system. Moreover, one of the major problems when setting up the devices is calibration of the sensors. In order to solve this, we utilize mobile robots in iSpace. The mobility of mobile robots allows us to cover wide areas of the environment without placing many landmarks in exactly known positions beforehand. Automated calibration of distributed laser range finders is performed based on the positions of the mobile robot in world coordinate system and their corresponding points in local coordinate system.