Design and implementation of hybrid indoor locating system

Indoor locating system usage has begun to increase last decades. Locating system usage in general and indoor locating system usage in specific applications are expected to find wide range of application areas in coming years. Patient and geriatric tracking in hospitals and rehabilitation centres, customer tracking for determining the shopping habit in malls and security based applications are foremost. GPS and GSM based locating systems used in outdoor have not capability to be operated in indoor. RF based locating systems are used in indoor applications, and WiFi based technologies are foremost because of their common usage. RFID technologies have limited applications due to their close distance reading capabilities. Ultrasonic technologies are additional technologies for locating, but they also are operating in very close distance. An important measure of locating system performance is its locating accuracy, and most of scientific studies have focused on minimizing locating error (vertical error, horizontal error and vector sum of them). With this purpose, an algorithm and system design are proposed for decreasing location error based on WiFi system. The most important reason of this mistake is due to the close distance Wi-Fi RF reading, and ultrasonic distance information is used for improving proposed system performance. An initial locating error is observed as 3.34(m) by using traditional WiFİ based system, this error decreased to 3.25(m) by improvement of Close Distance Error Elimination Algorithm(CDEEA). Proposed Hybrid Indoor Locating System (HILoS) indicates 3.13(m) at most. For 90% precision level, CDEEA accuracy is below 2.96(m) and HILoS accuracy is below 2.78(m). As a result , 6.28% improvement is observed between traditional system and proposed HILoS.