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Research On Passive Tag Indoor Localization Algorithm Based On Convex Relaxation In Multipath Environment

Posted on:2019-05-08Degree:MasterType:Thesis
Country:ChinaCandidate:X L MiaoFull Text:PDF
GTID:2428330593451626Subject:Circuits and Systems
Abstract/Summary:PDF Full Text Request
With the development of radio frequency identification technology,passive UHF RFID location has been concerned because of its easy deployment and low cost.However,indoor positioning environment is complex,wireless signals propagation is seriously affected by the ground,ceiling and obstacles.The signal received by the reader is the result of multipath overlay,which greatly reduce the ranging error between the reader and the tag to further reduce the positioning accuracy.The research to mitigate the impact of multipath propagation on the positioning accuracy is of great significance.Based on the classic indoor channel model,the indoor passive UHF RFID multipath channel model is proposed.In order to mitigate the impact of multipath propagation on the positioning accuracy,the multiple frequency signals sent by the reader are utilized to range.The ranging error is equivalent to a Gaussian distribution with the analysis of ranging error.Then the distance estimation model between the reader and the tag is established.In order to gain the location of the tag,the localization problem is transformed into convex optimization problem by semi-definite programming and second-order cone programming respectively.Firstly,the localization problem is transformed into an optimization problem.Then,the non-convex objective function is equivalently transformed into convex function.It is assumed that the distance estimation error is within an integral multiple of the Gaussian distribution standard deviation,which is added as a constraint to the convex optimization problem.Finally,the positioning algorithm based on semi-definite programming and the positioning algorithm based on second-order cone programming are proposed respectively.When there is no feasible solution to the convex optimization problem,the constraint is relaxed to gain the coordinates of the tag.Simulation results demonstrate that the proposed methods outperform traditional localization algorithms in multipath environment.
Keywords/Search Tags:Passive UHF, RFID, Multipath Channel, Multi-Frequency Phase Difference, Semi-Definite Programming, Second-Order Cone Programming
PDF Full Text Request
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