摘要
讲述了同步广播卫星电视时间信号的测量方法和测量结果，获得了CCTV1、CCTV2通过同一颗卫星（亚太－1A）转播的时延差值为16333μs，测量精度在10ns以内；CCTV2、CCTV4分别经两颗卫星（亚太－1A、亚洲－Ⅱ）转播，在陕西天文台卫星地面接收站时延差值为1644．20μs，精度为50μs，并分析了影响时延差值和精度的原因。同时测量了地方电视台转播亚太－1A的CCTV信号与直接接收亚太－1A的CCTV信号的时延差值，其测量精度为0．1μs。这些结果为利用同步广播卫星的电视信号进行高精度的时间服务提供了参考依据。
It is necessary for the users, who need time signals of high precision, to understandthe time delay of the received CCTV time signals. The methods for measuring the time delay of CCTV time signals re1ayed by synchronous satellite position and the measured results are described here. By these methods, the time delay difference between CCTV1 andCCTV2, which are relayed via the same satellite APATAR- 1A, is determined to be163. 33μs with the precision of 10ns. The time delay difference between CCTV2 andCCTV4, which are relayed via two satellites APSTAR-1A and ASIASAT-Ⅱ respectively, is determined to be 1 644. 20μs with the precision of 50μs. The analysis shows thatthe difference between CCTVl and CCTV2 is caused by the different locations of theirground stations and the tiifferent devices, while that between CCTV2 and CCTV4 ismainly caused by the different orbits of the two satellites and the variation of the differencewithin 50μs comes from their orbit related drifts. In addition, the precision for determining the time delay difference of CCTV time signals between the direct reception and the indirect reception (the signals re-relayed by a local TV station) is 0. 1μs. The results statedhere provides a reference basis for the high precision time service based on TV time signalsvia synchronous satellite broadcast system.
出处
《陕西天文台台刊》
CSCD
1997年第6期19-23,共5页
Publications of The Shaanxi Astronomical Observatiory
