A simplified detector for atomic clock anomalies detection

Environmental monitoring systems makes large use of satellite-based systems for the daily earth surface scanning. The accuracy of the final-user application that employs data acquired by using the satellite-based instrument strictly depends on the stability of the on-board atomic clock. It follows that a real-time monitoring of the frequency stability of the atomic clock is crucial for guaranteeing the reliability of the whole system. The Generalized Likelihood Ratio Test (GLRT) is a fault detection technique recently proposed also for revealing atomic clock anomalous behavior from acquired frequency data. To date, the GLRT detector to be applied to this specific application field has been evaluated by assuming no knowledge about the starting parameters values of the properly working clock. In this paper, a simplified GLRT detector, called GLRT SIMPLE, is presented and compared to the already published GLRT detector for faulty frequency data. It is shown that GLRT SIMPLE allows a faster algorithmic implementation and presents a larger sensitivity to common clock anomalies.