Research On Wireless Positioning Technology Based On WLAN In LBS System

With the rapid development of 3G and the technology of the Internet of things,LBS (Location Based Service) system, have become a new important growth point in the mobile services. In the LBS system, wireless location,as the basis for the other value-added services, accounts for the most important position. Existing GPS positioning technology and the base-station-based location technology are with low indoor positioning accuracy, high cost and also need to add special positioning module.Because of these, they are not suitable for the applications of precise positioning in indoor regions,and also difficult to be widely used in various types of terminals,which prohabit the value-added services in the LBS system. So it is difficult to widely use these technologies in the LBS system.In recent years WLAN technology is in the ascendant.With the rapid adoption of WLAN technology, WLAN is now widely used in crowded places, with the advantages of widely located throughout the region's key places, low cost and high transmission rate WLAN positioning technology can be effectively used in the indoor environment. The existing WLAN positioning technology has achieved some results yet still with the disadvantages like low precision and heavy loads of signal acquisition. Therefore, with the analysis of needs of the LBS system,which has a wide range of business and involves all kinds of terminals with complex indoor environment,we mainly designed a WLAN-based wireless location method which can be widely used in the LBS system using the received signal strength difference and the processes of .We mainly discussed the following.First,we introduced the main points of WLAN technology and the procession of WLAN positioning, and the existing WLAN wireless location technology is analyzed and compared, particularly the fingerprint method and signal propagation modeling, and the existing WLAN positioning system are briefly introduced, then we compared the advantages and disadvantages of these technologies.Then, the special needs for location of the LBS system are introduced and analyzed, ,and then we designed two processes of the signal strength collection,and also a signal loss model based on above,then we pointed out that the existing fingerprinting and signal propagation models and the other methods are not suitable for the LBS system. Then with the basis of the above, a new WLAN-based wireless location method was presented. The method used the received signal strength difference between differnt receive points to calculate the locating device position, thus effectively reducing impact on the location becausethe complexity of the indoor environment, all kinds of terminal performance parameters and other factors.The method was carried out in the real environment test, and we compared its performance in the indoor corridor environment and the office environment, and we analysed the experimental results with the existing WLAN positioning technology.