Applications of Time and Frequency in Geodesy

Abstract

Many geodetic measurements, especially those using space techniques require very precise time and frequency devices. In this paper, some applications of time and frequency in Satellite-Geodesy are discussed with reference to several observational techniques. Precise laser range measurements to artificial satellites or to the moon using stationary or mobile systems in the centimetre domain need not only a very precise time interval counter or event timer but also the access to a stable and globally available time scale, especially if the data will be used with only short delays or even in real time. New techniques such as interferometry for the determination of short, medium and very long baselines require time and frequency devices with best characteristics in both the short-term and the long-term stability.