中文摘要：

为了更好地计算GPS CV（共视）时间传递中的电离层时延值（它是影响CPS CV比对结果精度的主要因素之一），介绍了当前3种电离层时延的计算方法，并以NICT（National Institute of Information and Communications Technology）单站GPS比对数据及NICT与NTSC（National Time Service Center）的GPS共视比对数据为例，分析比较了不同的电离层时延计算方法对GPS时间比对结果精度的影响。计算结果表明：利用双频实测电离层时延和利用ICS（International GPS Service）提供的TEC（total electton content）map计算的电离层时延对GPS CV比对结果修正后的精度，比利用电离层改正模型的时延对比对结果修正后的精度分别提高30％～40％和20％～30％。

英文摘要：

For more accurately calculating the ionospheric delay in GPS CV （common view） time transfer, which is one of the main factors to affect GPS CV time comparison precision, three different methods of calculating the ionospheric delay are introduced and the different effects of the different calculating methods on the precision of GPS CV comparison are compared and analyzed with the GPS comparison data of NICT（National Institute of Information and Communications Technology） and GPS CV comparison data of NICT-NTSC（National Time Service Center） as some examples. The results show that the precision of GPS CV time transfer in which the ionospheric delay is corrected by using the double-frequency measure and the precision of GPS CV time transfer in which the ionospheric delay is corrected by using the TEC map issued by IGS （International GPS Service） are raised by 30%-40% and 20% -30% respectively compared with the precision of GPS CV time transfer in which the ionospheric delay is corrected by using the ionospheric correction model.