Time and Frequency Stability for the Crystal Dynamics Project

R. Coates, J. Ryan, T. Herring

Abstract:	The Crustal Dynamics Project utilizes very long baseline interferometry (VLBI) and laser ranging to artificial satellites and the moon to determine vector baselines between stations with precisions of about one part in 106. Both laser ranging and VLBI require initial relative epoch timing of about one microsecond for stations distributed over the globe. Very stable frequency standards are the key to VLBI because they are used to maintain frequency coherence between stations. In order to have less than one radian rms X-band phase perturbation accumulated in a 1000 second integration period, the frequency standard must have a stability of 1 x 10-14. In the VLBI data analysis to determine accurate baselines, the clock offsets and variations must be solved for in order to fit the data with less than 0.1 nsec (3 cm) is deviation over 24 hours.
Published in:	Proceedings of the 12th Annual Precise Time and Time Interval Systems and Applications Meeting December 2 - 4, 1980 Goddard Space Flight Center Greenbelt, Maryland
Pages:	649 - 662
Cite this article:	Coates, R., Ryan, J., Herring, T., "Time and Frequency Stability for the Crystal Dynamics Project," Proceedings of the 12th Annual Precise Time and Time Interval Systems and Applications Meeting, Greenbelt, Maryland, December 1980, pp. 649-662.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In