LTE Transmitter Location and Clock State Estimation: Simulated and Real Measurements Using the SSS and CRS Signals

Abstract

The use of Long Term Evolution (LTE) communication signals has been extensively studied in literature as a complementary positioning system for GNSS in GNSS denied scenarios, such as urban canyons or indoor environments. However, in order to achieve accurate positioning with LTE signals, the transmitter location and clock state information is required, which is not provided by the system. This paper presents the estimation of the LTE transmitter position and clock states by using the LTE Secondary Synchronization Signals (SSS) and Cell-specific Reference Signal (CRS). Herewith, an analysis of the LTE SSS and CRS signals is done at a theoretical level to identify performance limitations when employed as 10 ms-long local replica in a GNSS-like processing and a comparison of transmitter localization results, obtained using these signals, is presented. Receiver optimizations for LTE signal compatibility are discussed within the context of extending the Multi-Sensor Analysis Tool (MuSNAT) software receiver for LTE SSS and CRS acquisition and tracking. The complete processing chain, which is based on MuSNAT and a MATLAB based LTE transmitter localization filter, has been validated based on simulation and is then employed for two commercial base stations and research purposed Amarisoft LTE/5G base station.