DILSA: distributed in-door location system architecture

One of the major issues in the in-door location system is the exact transfer of location data to a mobile node that pursues its current location. The GPS, which is a popular location finding tool in out-door environment, can not be used in in-door environment. Besides, lots of environmental restrictions exists in the indoor other than in the out-door. In this paper, DILSA (distributed in-door location system architecture) is presented to provide accurate location finding in the in-door environment. DILSA uses a sequential routing algorithm. The algorithm is proposed to prevent a mobile node from receiving unnecessary location data from beacon nodes. A mobile node finds out the nearest beacon node by calculating the TDoA (time difference of arrival) between RF and ultrasonic wave to improve the location accuracy. The experimental results show that DILSA has a high accuracy of location estimation