Title :
A study of delay instabilities within a two-way satellite time and frequency transfer Earth station
Author :
Shemar, Setnam L. ; Davis, John A.
Author_Institution :
Centre for Time Metrol., Nat. Phys. Lab., Teddington, UK
Abstract :
The accuracy of the Two-Way Time and Frequency Transfer (TWSTFT) technique has been shown to be limited by propagation delay instabilities present in the Earth station hardware. In this paper the National Physical Laboratory (NPL) has investigated a scheme for reducing delay instabilities in order to improve the accuracy of its time and frequency transfer. Tests show that cables propagating signals at 70 MHz or L-band have much lower temperature coefficients than cables propagating at Ku-band when measured with TWSTFT modem. A scheme for improving Earth station stability by propagating signals through cables at 70 MHz or L-band wherever possible has been investigated. It is found that lower temperature coefficients are possible by adopting this scheme. Comparisons are also presented with tests carried out using a higher chip rate
Keywords :
delays; frequency standards; microwave links; satellite ground stations; stability; time measurement; transfer standards; 70 MHz; Earth station; Earth station stability; Ku-band; L-band; NPL; National Physical Laboratory; TWSTFT; accuracy; chip rate; delay instabilities; frequency transfer; propagation delay instabilities; temperature coefficients; time transfer; two-way satellite communication; Cables; Delay effects; Frequency; Hardware; L-band; Laboratories; Propagation delay; Satellite ground stations; Temperature; Testing;
Conference_Titel :
Frequency and Time Forum, 1999 and the IEEE International Frequency Control Symposium, 1999., Proceedings of the 1999 Joint Meeting of the European
Conference_Location :
Besancon
Print_ISBN :
0-7803-5400-1
DOI :
10.1109/FREQ.1999.840744
