Study of Fingerprint Location Algorithm Based on Wifi Technology
Aiming at the problem that the anti-disturbance poor ability of the wifi fingerprint location algorithm and the positioning accuracy to be improved. This paper takes the direction effect of the signal into consideration and establishes fingerprint database by using a new data acquisition and filtering techniques. At the same time, it uses dynamic joint WKNN algorithm and combines with two different ways of allocating weights to realize localization in the matching phase. Experimental results show that the proposed method can improve the stability and precision of positioning to a certain extent. Introduction With the rapid development of the mobile internet and the wide application of pervasive computing technology, the demand of mobile user's location information for lots of public and business services increasing gradually. However, the accuracy of GPS positioning declined even unable to locate because of the building and other disturbances leading to the satellite signal attenuation [1]. People not only need the precise positioning of the outdoor but the indoor positioning accuracy requests are increasingly high. In recent years, a large number of positioning technologies sprang up in the field of indoor positioning including Assistant-GPS technology, infrared positioning, bluetooth location, wifi indoor positioning [2], etc. Wifi technology has been widely used with the advantages of low hardware requirement, low cost, wide coverage, and fast transmission speed [3]. At present, the wifi localization method is mainly divided into two types: based on the model and the signal strength. Algorithm based on the model converts the received signal strength (RSS) value to the distance to determine the current position using the model with high accuracy, but the algorithm based on signal strength compares signal features and fingerprint information which position required to obtain the target location by establishing the wireless signal strength database and location information[4]. The ability of conventional wifi fingerprint location algorithm is poor as well as the positioning accuracy to be further improved. Aiming at the problem, this paper studies a location fingerprint algorithm based on wifi location technology. A new method of data collection and filtering is adopted to build the fingerprint database. And using a kind of dynamic joint WKNN algorithm to carry on the indoor localization to improve the position accuracy to some extent. Wifi Technology for Indoor Location Wifi indoor positioning is currently the main application of the algorithm is the location fingerprint matching algorithm, including two stages with off-line acquisition and online match: Off-line acquisition and construction of fingerprint database, after collecting and processing the fingerprint data from different reference positions in the areas to be located, storing it into the fingerprint database in the form of <site,fingerprint>. To get location information online through matching the signal from a position to the fingerprint in the database, and let the position corresponding a optimal matching fingerprint to be the positioning results [5]. For instance, the WKNN algorithm with determine the position which needs to be measured though calculating the distance between the RSS vector and the RSS vector in the