Self-correction scheme by adjusting the navigation signal transmission time

Abstract

Pseudolite-based systems and airborne relay-based positioning system (ARPS) have a limitation wherein the position error increases as the distance between the user and the area where the segments of the system are configured increases, owing to the low altitude of the navigation signal transmitters. To enhance the accuracy of the user, we propose a self-correction scheme based on the ARPS. In the proposed correction scheme, each reference station adjusts the transmission time of the navigation signal. This adjustment time is determined by calculating the average pseudorange differences between the true/estimated positions of the reference station and the estimated position of each airborne relay. Regardless of this adjustment, the user estimates the positions of the airborne relays and its own based on the original transmission time. Owing to this characteristic, the pseudorange errors that are included during the signal propagation are corrected and the accuracies of the airborne relays and the user are improved. Simulation results show that the proposed correction scheme reduces the error of the user, and the user in an enemy area can be provided with a relatively high accuracy service without the aid of correction messages.