Research On Indoor Wireless Location

With the maturity and development of the communication technology, people's demand for wireless location is increasing grows day by day. Provide user with wireless location service has been widely used in the outdoor and car navigation, for example: GPS and GSM location. But in the indoor environment, these service performances are insufficient to meet special need. As a hot research topic, indoor location technology receives more and more attention.As the indoor wireless environment is complex, the decline is serious, multi-path effects are obvious, and the signal is weak. These traits make indoor wireless location has distinct characteristics which is different form general location system. Therefore, the difficult of indoor location is relatively higher than others. At present, common method is structure small-scale location network under indoor environmentThis article analysis the indoor wireless location technology, and focus on how to improve indoor wireless location accuracy.Indoor wireless transceiver equipments are varied, the corresponding measurement methods are different. This article analysis the advantages and disadvantages of four different methods: RSS, TOA, TDOA, AOA.This article research the different algorithms such as circle method, least squares, centroid, based on RSSI. To these commonly used methods, do simulations, analysis the location accuracy of these methods, compare the advantages and disadvantages.For the shortcomings of circle methods, use the maximum likelihood function do the indoor wireless location estimation. We analysis maximum likelihood methods in positioning precision, ease of implementation, characteristics of the areas of commonality, compared with the previous algorithm. Then we collected data with MSP430 in our real environment, verify the maximum likelihood function algorithms appearance.Indoor wireless devices are usually low-power equipped, in order to cover the entire indoor environment, use several transceivers to format a network is very necessary. This leads to the research on the distribution of transceiver, proposed structure of the cellular layout based on the hexagonal grid. We analysis the accuracy of indoor wireless location based on cellular layout, and find out the factors increase the location accuracy. Based on how to choice the nod, we put forward a new method to obtain higher location accuracy.