Improved Time-of-Arrival Estimation Algorithm for Cellular Signals in Multipath Fading Channels

Abstract

Positioning using the time-of-arrival (TOA) of cellular signals has emerged as a promising solution in global navigation satellite system (GNSS) challenged environments, such as in urban canyons and indoors. However, harsh multipath fading propagation condition remains as one of the key factors causing the detriment of the TOA estimation accuracy. This paper presents an improved TOA estimation algorithm for cellular signals in multipath fading channels. The proposed algorithm takes advantage of the super-resolution algorithm and multipath estimating delay lock loop for estimating the multipath parameter vector. The estimation results are constantly monitored to handle the multipath fading conditions. At the beginning of each update epoch, the proposed method performs a consistency check using the previous estimated parameter vector to determine whether to activate a reinitialization process or not. While at the end of each update epoch, the method examines the validity of the detected first arriving path to remove the estimation outliers. Simulation results considering a five-path fading channel are provided to demonstrate the effectiveness of the proposed algorithm and compare its performance to those of other existing approaches.