Precise calibration method of pseudolite positions in indoor navigation systems

Abstract

A pseudolite is a signal generator that transmits a CPS-like signal. Using pseudolites, we developed an indoor navigation system. An indoor navigation system has several positioning error sources, such as time-tag error, multipath error, near/far problem, and pseudolite position error. Among them, we can remove the pseudolite position error by precise calibration because pseudolites are fixed. Otherwise, there would be bias-type positioning errors in indoor navigation solutions. Therefore, how exactly the pseudolite positions are calibrated determines the limit of the indoor navigation system's performance. With this motivation, we made efforts to develop a precise calibration method of pseudolite positions in an indoor navigation system. This paper proposes a practical and accurate calibration method, which uses only pseudolite signals. Simulation results showed that we can calibrate all the pseudolite positions within two or three centimetres by this method.