分析了在卫星双向时间频率传递中，由地面站间钟差和卫星运动引起的双向几何路径不对等导致的双向几何路径时延差对双向时间比对计算结果的影响。选取了3颗卫星（中卫1号、北斗3G、IGSO70）和3组地面站（北京-成都、北京-喀什、北京-三亚）组成的9条卫星双向时间频率传递链路作仿真计算。对于这9条链路，仿真结果显示：1）当两地面站间钟差在1μs～10 ms范围内时，通过GEO卫星比通过IGSO卫星的双向不对等几何路径时延之差对双向时间比对计算结果的影响（τ值）较小；2）假设地面站间钟差在1 ms内时，通过 GEO卫星的卫星双向时间比对链路所对应的τ值均在皮秒量级，一般可忽略；通过 IGSO 卫星的卫星双向时间比对链路所对应的τ值均在纳秒量级，一般不可忽略。%The effect of the difference of the time delay, which results from the two-way nonreciprocal geometric path due to the clock offset between the two stations and the satellite motion, on the results of TWSTFT (two-way satellite time frequency transfer) is analyzed. A simulation is conducted for 9 links of TWSTFT, which relate to 3 satellites(chsat-1, BD-3G, IGSO70) and 3 pairs of station(Beijing-Chengdu, Beijing-Kashi, Beijing-Sanya). The simulation shows:1)when the clock offset between the two stations is between 1 ms and 10 ms, the effect of two-way nonreciprocal geometric path via GEO satellite on the result of TWSTFT, i.e.τvalue, is less than that via IGSO satellite;2)when the clock offset between the two stations is less than 1 ms, the effect of two-way nonreciprocal geometric path via GEO satellite on the result of TWSTFT, i.e.τvalue, is in the order of picosecond and can be ignored, while that for the path via IGSO satellite is in the order of nanosecond and final to be ignored.
展开▼
