Research And Improvement Of Acquisition And Tracking Algorithm For High Sensitivity TC-OFDM Indoor Location Receiver

With the rapid development of social economy,the location based service(LBS)is playing an increasingly important role in daily life.In the outdoor environment,GPS,Beidou,Galileo,GLONASS and other positioning systems have been able to meet most of the needs.However,in the indoor environment,there are still some technical challenges.TC-OFDM(Time&Division Orthogonal Frequency Division Multiplexing Code)in this thesis is a location based service system which can provide a wide area high precision indoor and outdoor positioning.In this thesis,some key techniques of TC-OFDM indoor positioning system are researched,and the acquisition and tracking algorithms of TC-OFDM positioning system are emphatically analyzed.At the same time,a series of experiments are carried out.The main contents are as follows:(1)The signal structure of TC-OFDM indoor positioning system is introduced,and the architecture of TC-OFDM indoor positioning and receiving terminal and the baseband algorithm flow are analyzed.And the acquisition and tracking algorithms used in the current system are introduced and analyzed.(2)The study and improvement of the weak signal acquisition algorithm,the advantages and disadvantages of the coherent integration algorithm and non-coherent integration algorithm are analyzed.In order to solve the square loss problem,a noncoherent and coherent joint acquisition algorithm based on noise power compensation and a noise power compensation algorithm based on auxiliary channel measurement are proposed.At the same time,a segmented FFT/IFFT acquisition algorithm is proposed for the contradiction between the long FFT acquisition algorithm and hardware resources.(3)The tracking algorithm of indoor environment is studied and the widely used tracking algorithm and frontier research are analyzed.And a dynamic threshold carrier loop based on the combination of frequency locked loop and phase locked loop is proposed for the indoor environment with severe signal attenuation and low dynamic performance.This loop is designed to adapt to different conditions of carrier tracking.(4)The noise power compensation algorithm based on the auxiliary channel measurement proposed in this thesis is simulated and tested respectively with the dynamic threshold carrier loop based on the combination of PLL and PLL.