A GPS-synchronized oscillator ( English GPS disciplined oscillator , GPSDO ) is a crystal oscillator whose frequency with the signals from GNSS is controlled systems, resulting in a higher order of magnitude stability and accuracy is obtained.
ID Kitching, DW Allan, TK Peppler: Frequency and time stability of GPS and GLONASS clocks. In: P. Daly (Ed.): Proceedings of the 44th Annual Symposium on Frequency Control. 1990, pp. 127-139. ( online (PDF file; 1.05 MB)).
B. Shera: A GPS-based frequency standard. In: QST . July 1998, pp. 37-44.