Short-Term Characterization of GPS-Disciplined Oscillators and Field Trial for Frequency of Italian Calibration Centers
Abstract
Quartz and rubidium oscillators disciplined by the signals of the Global Positioning System satellites (GPSDOs) are increasingly used as reference standards in calibration centers and in telecommunication networks, thanks to their cesium-like long-term instability, and several investigations are undergoing in the metrological laboratories of different countries concerning their use for the traceability to the national standard of time. Some of these devices were tested in the past at the Time and Frequency Laboratory of IEN, as regards to their use as frequency and time references in secondary laboratories and their traceability to the Italian standard of time. In further investigations performed, evidence was found of short-term frequency instabilities, not previously detected, mainly due to temperature effects and to the disciplining algorithms used, that must be taken into account especially in the frequency calibration field. The long and short-term instability results obtained at IEN on some GPSDOs, that show the real uncertainty limits in calibration, are reported in this paper. They are also checked by means of a field-trial on frequency, carried on among some Italian Calibration centers equipped with GPSDOs or other frequency references, using either a free rubidium or a quartz oscillator as travelling standards.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1998
- Accession Number
- ADA508566
Entities
People
- F. Cordara
- V. Pettiti