Research On Indoor Positioning Method Based On Carrier Phase

With the evolution of communication standards,indoor positioning application scenarios become more diverse and positioning requirements become more stringent.In outdoor scenes,the positioning technology based on GNSS has been widely used commercially.However,in indoor scenes with complex signal propagation environment,the positioning accuracy of GNSS is not high,and it is difficult to support related positioning applications.However,there are more positioning application requirements in various indoor application scenarios.Therefore,how to realize high-precision and fast-response positioning in indoor environment has become a research hotspot in the field of positioning.In this thesis,after fully studying the mainstream indoor positioning technology,three indoor positioning schemes based on carrier phase are proposed in the indoor cellular wireless network environment,and the proposed positioning schemes are simulated and analyzed.The main work of this thesis is as follows:Firstly,the carrier phase technology is introduced into the existing cellular network deployment,and the problems that need to be solved in the application of carrier phase technology in indoor cellular networks are analyzed.Then,aiming at two key problems,namely,the negative impact of system asynchronization on positioning and integer ambiguity resolution,an indoor carrier phase positioning scheme based on clock offset elimination and a high-precision and fast positioning scheme based on carrier phase are proposed.In the former,a reference terminal is introduced into the positioning scene,and a clock offset elimination scheme is designed to completely eliminate the influence of time-varying clock offset.Then,an integer ambiguity resolution algorithm is designed based on the three-difference carrier phase equation to eliminate time-varying clock offset,and the positioning accuracy of centimeter level is obtained.Aiming at the limitation of the former,the latter designs a fast integer ambiguity resolution algorithm,which shortens the positioning time on the premise of ensuring the positioning accuracy.Secondly,in order to solve the problem that some nodes to be located in the network can’t locate themselves or have low positioning accuracy due to the lack of visible reference points,a cooperative positioning scheme based on carrier phase is proposed.This scheme can make full use of the mutual measurement information between nodes,decompose the objective function of cooperative positioning based on Bayesian principle,and realize fast calculation of posterior probability distribution of nodes to be located by sum-product algorithm based on factor graph.The simulation results show that the scheme can accurately solve the integer ambiguity on the link and improve the positioning accuracy of the node to be located.