Measurement Analysis of an Indoor Positioning System Based on LTE

Location information is playing an increasing important role in people's life. Specially, indoor positioning systems have been sufficiently researched to provide location information for persons and devices. This paper focuses on the research and development of the indoor positioning system based on LTE uplink signal, which consists of transmitter, Location Measurement Unit (LMU) and server. The Sounding Reference Signal (SRS) is employed as the excitation signal for the estimation of TDOA because of its good autocorrelation. The LMU is used for signal processing and Time-Difference of Arrival (TDOA) calculation, which is connected with four segregate received antennas. Synchronization is not necessary between any two LMUs. Therefore, they can be flexibly deployed on Base Stations (BSs). Additionally, a spatial filtering algorithm without the prior information is proposed to optimize the route tracking. The test results demonstrate that the fixed point positioning error is less than 3 m, and the estimated trajectory is basically accordant with the real path in the dynamic test.