LTE transmitter states estimation using a combined code and carrier phase observation model

This paper presents a localization framework that consists of a combined code and carrier phase observation model and can be used to estimate the unknown position and clock states of a Long Term Evolution (LTE) transmitter for navigation. The LTE signals are tracked within a Global Navigation Satellite System (GNSS) type receiver architecture, using Multi Sensor Navigation Analysis Tool (MuSNAT) software receiver, for four dynamic receiver trajectories around a target base station. The low noise carrier phase observation enables estimation of the base station position up to sub-meter level accuracy for signal measurements having a sufficiently long duration of stable carrier tracking. The paper presents the localization results of a research-oriented Amarisoft base station pertaining to two receiver platforms - a ground vehicle and an airborne Unmanned Aerial Vehicle (UAV). For each platform, the received LTE signal quality is first analyzed using Code-Minus-Carrier (CMC) time series and then for time durations where the code and phase tracking is stable, the observations are fed into a Kalman filter which estimates the transmitter 3-dimensional position, clock bias and drift over time as well as the LTE carrier phase float ambiguity. The estimated position states results are then compared against a ground-truth measurement of the transmit antenna coordinates, which is obtained using GNSS Real Time Kinematic (RTK) and triangulation with a surveying multi-station device.