Research On Indoor Localization Based On Pseudolites

With the development of society and economy,the application of LBS(Location Based Service)is more and more widely.LBS is a value-added services being provide to the users by getting the users' location information.The way to get location is by radio communication network or GPS.The same urgent demand as indoor environment.All of these can be achieved based on the positioning.GNSS(Global Navigation Satellite System)has been widely used outside.However,GNSS can't finish positioning due to the obstruction of wall.This paper will introduce a pseudolite indoor positioning system and resolve the problems as below,(1)Pseudolite system composition and the antenna optimization layout.This paper builds a interior pseudolites' system structure as well as outdoor navigation satellite system by high-performance navigation signal simulator.What's more,near-far effect as constraint condition,eventually it's reasonable that forming a regular hexagon structure to optimize the layout of pseudolite.(2)Fixed satellite position message broadcast technology and calculation method.Compared with the high speed movement of the outdoor navigation satellites,the characteristics of the indoor pseudolites is stationary.We can amend the related to the speed of quantity to zero and the scaling factor so that make use of traditional six orbital elements to calculate the stationary pseudolites.This paper deals with the process in detail and example is given.(3)Pseudolite time synchronization technology and transmitting antenna design.In this paper,the centralized and distributed pseudolite indoor positioning system comes up.And experiments have been carried out to the centralized structure.The distributed pseudolite structure uses pseudorange two-way time synchronization method and the transmitting antenna design and simulation experiments.Beyond that,this paper for the initial value selection,two-dimensional localization algorithm and multipath detection etc are also discussed.Conclusion,the content of this paper mainly moves around the four difficulties of pseudolite applications: Near-far effect,pseudolite signals encoding,time synchronization and the multipath effect.And tests prove the feasibility of the system.The location accuracy can achieve decimeter level.Compared with Wi-Fi and Bluetooth technology,the functions of launch power,positional accuracy and indoor-outdoor positioning compatibility have obvious enhancement.