Protecting signal integrity against atomic clock anomalies on board GNSS satellites

This paper introduces a method of detecting atomic clock anomalies of GNSS satellites and presents some results obtained from processing real GNSS data. The method employs a Kalman filter formulation which facilitates real-time processing of GNSS carrier-phase measurements. Decision on the onset of clock anomalies is made using the prediction interval approach, where actual distribution of relative phase difference data between satellite and ground clocks is replaced by a Gaussian overbounding distribution. Results obtained from processing real GNSS data shows that the method appears as a suitable tool for real-time detection and identification of GNSS clock anomalies.