中国综合时号改正数系统世界时中短周期项的检测

为了检测中国综合时号改正数系统世界时中的潮汐短周期项,本文应用中国《授时年报》和《BIH年报》的有关资料,归算得到一个1967—1978年期间中国时号改正数系统中世界时的连续序列。然后用自相关功率谱分析检测这个序列中的短周期项,没有发现这些项的存在。进一步用互相关功率谱分析检验这个序列,也证实了同一结论。作为对照,用自相关功率谱分析检测短周期项的理论值序列和BIH的世界时序列,都得到了显著的短周期项功率谱。看来测时处理中的过度平滑是导致这一结果的原因。因此,建议在平滑测时结果时,选取合适的平滑因子,减弱平滑强度,以保留短周期项。

A DETECTION OF SHORT-PERIOD TERMS IN UNIVERSAL TIME OF CHINESE JOINT SYSTEM

The purpose of this paper is to detect the tidal short-period terms in universal time (UT) of Chinese Joint System (CJS). A reduction of the relevant data in "Annual Report of Chinese Time Service" and "Annual Report of BIH" gives a consecutive series of UT of CJS at the interval from 1967 to 1978. Then an auto-correlation analysis detects the short-period terms in this series and shows an absence of the expected terms. Furthermore, an analysis of cross-correlation power spectrum tests this series and confirms the conclusion obtained above. In contrast with this result, the same analyses of both the theoretical series of tidal terms and the, BIH series of UT demonstrafe the notable power spectrum of the short-period terms. It seems that the excess in smoothing of time measurements led to this consequence. Our proposal, therefore, is the appropriate choice for the smoothing factor to weaken the smoothing intensity and to retain the short-period terms.