RT Journal Article SR Electronic T1 Improved Automatic Detection of GPS Satellite Oscillator Anomaly using a Machine Learning Algorithm JF NAVIGATION: Journal of the Institute of Navigation JO NAVIGATION FD Institute of Navigation SP navi.500 DO 10.33012/navi.500 VO 69 IS 1 A1 Yunxiang Liu, A1 Y. Jade Morton YR 2022 UL https://navi.ion.org/content/69/1/navi.500.abstract AB This paper presents a random forest-based machine learning algorithm to automatically detect satellite oscillator anomalies using dual- or triple-frequency GPS carrier phase measurements. The algorithm can distinguish satellite oscillator anomalies from other GPS carrier phase disturbances including ionospheric scintillation and receiver oscillator anomalies. Carrier phase power spectral density and carrier phase ratios between carriers are extracted from measurements and applied as input features to the random forest algorithm. The method is trained using data collected at seven GNSS monitoring stations located in Alaska, Ascension Island, Greenland, Hong Kong, Peru, Puerto Rico, and Singapore. The overall detection accuracies of 98.4% and 99.0% are achieved for dual- and triple-frequency signals, respectively. The method outperforms other machine learning algorithms. The preliminary detection results demonstrate that the method presented can be employed on a global satellite oscillator anomaly monitoring system.