对流层散射双向时间比对中对流层斜延迟估计

Tropospheric slant delay estimation in two-way troposphere time transfer

为精确估计对流层散射双向时间比对系统中对流层斜延迟,分析了估计卫星信号对流层斜延迟的Hopfield天顶延迟模型及CFA2.2映射函数模型并对其进行修正,从而适用于对流层散射斜延迟的精确估计。根据北纬35°~37°范围内的三个测站2010—2012三年的气象数据,验证Hopfield模型精度范围小于35 mm,并将三个测站按相互之间基线距离的不同分为三组比对站,利用2012年的气象数据,计算在不同入射角下一年的对流层散射斜延迟,并得出最大斜延迟对应的年积日和入射角。结果表明,三组比对站的最大单向散射斜延迟为21.82~35.45 m。在双向比对抵消90%的情况下,时间延迟为7.3 ns^11.7 ns;相互抵消95%时,时间延迟为3.6 ns^5.9 ns。

In order to accurately estimate the tropospheric slant delay of the two-way troposphere time transfer system, the Hopfield zenith delay model and the CFA2.2 mapping function model which can estimate the tropospheric slant delay of satellite signals were analyzed and modified, and was accepted by the accurate estimation of slant delay caused by tropospheric scatter. The meteorologic data of three observation stations from 35°N to 37°N in 2010--2012 were selected to verify that the precision range of Hopfield model was less than 35 mm. Then, in order to calculate the tropospheric delay under different angle of incidence through modified model, three observation stations were distinguished by different baseline distance and the meteorologic data of those stations in 2012 were used. The day of year and the incident angle under maximum slant delay were also obtained. Results suggest that the max delay is 21.82 m to 35.45 m in a single way time transfer. In two-way time transfer, when the delay is counteracted by 90% or 95%, the time delay is 7.3 ns - 11.7 ns or 3.6 ns -5.9 ns.