Research Of Hybrid TOA/INS Indoor Localization Algorithm

With the increasing demands of high accuracy positioning, indoor positioning is drawing more and more people’s attention. Comparing to outdoor conditions, indoor environment is more complex and easier to reduce the accuracy of the carrier, however,using only one method of indoor positioning may not achieve the required positioning accuracy. With the development of computer and telecommunications, joint positioning can make up for this disadvantage and can improve positioning accuracy. Experts and researchers around the world has focused on this area. Among them, as one of the basic wireless location technology, Time of Arrival(TOA) positioning technology is practical;what is more, with the development of inertial components, more and more attention has been focused on Inertial Navigation System(INS). Both of them have advantages and limitations. The joint positioning program of TOA/INS is proposed and researched in the following three aspects.First, some researches about TOA have been done. The main algorithm of TOA includes linear estimation method and the approximate maximum likelihood estimation.A Cramer-Rao Low Bound of TOA has been deduced in order to provide a standard for the distance measurement error of the target node. In one scenario, the ranging error of the target node is analyzed from numbers and arrangement of the reference node and noise intensity, the positioning accuracy is achieved and the good layout between nodes is given, meanwhile, some advantages and disadvantages of TOA are analyzed at last.After that, the two-dimensional algorithm of INS is researched. INS algorithm could realize continuous positioning and keep high accuracy at a period of time; INS couldn’t provide initial positioning information for the carrier. The accumulative error will increase with time increase and the main error of INS comes from gyroscope.The joint positioning program of TOA/INS is given in this thesis, and the program is based on interior environment. In the thesis, the indoor environment is divided into line of sight scenario and non-line of sight scenario. In the line of sight scenario, TOA positioning system-based and INS positioning system supplemented; in non-line of sight or from the line of sight to non-line of sight, INS positioning system-based and TOA positioning system supplemented. Each positioning mode is analyzed and achieved the purpose of the joint positioning.According to some results of this thesis, using TOA/INS position could improve the location accuracy and realize continuous positioning of the carrier.