Accession Number : ADP004606

Title :   Time Synchronization Experiments with Apple,

Corporate Author : NATIONAL PHYSICAL LAB NEW DELHI (INDIA)

Personal Author(s) : Jain,C. L. ; Kumar,K. ; Sivaraman,M. R. ; Mathur,B. S. ; Banerjee,P.

Report Date : 02 APR 1984

Pagination or Media Count : 9

Abstract : Several Time Transfer/Synchronization techniques viz transmissions of 1PPS, TV Passive, TV Active, transmission of INSAT Time Code etc. were tried out on the Indian Experimental Satellite APPLE. The availability of the APPLE Satellite for a long time gave us the opportunity to try out various new techniques which could not be tried out earlier on Symphonie and to firm up the specifications of the hardware required to be developed for various catagory of users when INSAT becomes available on an operational basis for the dissemination of Standard Time and Frequency. The drift of APPLE Satellite in its orbit was found to be about 150 meters/sec. Because of such large change in the range of the satellite it was not possible to achieve expected accuracies in the time transfer. Due to the availability of only one transponder on board, most of the experiments were conducted in quasi-simultaneous mode. The use of 2nd order range extrapolation technique to correct for the satellite range helped us to get better time transfer accuracies than was possible with linear extrapolation. Using the techniques of 1PPS, ranging to the APPLE was carried out and orbit computation was attempted and used in a TV passive technique. In this paper results of various experiment conducted on APPLE are presented. (Author)

Descriptors :   *SYNCHRONIZATION(ELECTRONICS), *ARTIFICIAL SATELLITES, TELEVISION TRANSMITTERS, DRIFT, COMPUTER APPLICATIONS, SPECIFICATIONS

Distribution Statement : APPROVED FOR PUBLIC RELEASE