A GPS L1 and Cellular 4G LTE Vector Tracking Software-Defined Receiver

Abstract

In this thesis, a traditional GPS L1 vector tracking receiver is augmented with cellular 4G LTE channels. The hybrid receiver can acquire and track GPS L1 and LTE signals simultaneously in an extended Kalman filter-based vector tracking loop. The receiver uses either the secondary synchronization signal or the cell-specific reference signal to track the LTE signals. First, the open-loop pseudorange and pseudorange rate errors are provided as a function of the carrier-to-noise ratio. A method to calculate the carrier-to-noise ratio of the LTE signal using correlator outputs is also provided. The code phase and carrier frequency tracking accuracy of the receiver is derived in theory using the Discrete Algebraic Riccati Equation (DARE) and validated by Monte Carlo simulations. The effects of errors, such as eNodeB localization error and multipath, are evaluated in Monte Carlo simulations as well. The robustness of the combined vector tracking loop to GPS outages is also evaluated in Monte Carlo simulations. Finally, the positioning accuracy of a prototype of the hybrid receiver is shown experimentally.