Global ionosphere maps (GIM) computed from dual-frequency GNSS measurements have been widely used for monitoring ionosphere as well as providing ionospheric corrections in Space Geodesy since 1998. This work focuses on a comprehensive study of the influence of time resolution on GIM performance. One and a half solar cycle of the IGS GIM with higher time resolution and accuracy (the UPC-IonSAT Quarter-of-an-hour time resolution Rapid GIM, AKA uqrg) has been taken as baseline to downsample them to all possible sub-daily temporal resolutions. The performance of the resulting GIMs has been assessed by directly comparing with external vertical total electron content (VTEC) measurements from Jason altimeters over oceanic regions. In order to perform a complete assessment and analysis of involved GIMs, the influence of geographical position and solar and geomagnetic activities was also taken into account during more than one solar cycle. In addition, to have a clear view at the smaller time resolutions, a more accurate assessment, the dSTEC test based on external GNSS measurements not used in the GIM generation was also done during two solstice and two equinox days in 2015 over continental regions. The assessment shows that discrepancy among GIMs with different time resolutions becomes more apparent at low latitudes and also at high solar-geomagnetic activity. The results also suggest that the accuracy for GIMs with time resolution smaller or equal to 60 min is consistent during the period from 2002 to 2019 and is more accurate than other GIMs with lower temporal resolution. Accordingly, high time resolution (including 15, 30, 45 and 60 min) is recommended for the application of GIMs with the highest accuracy.

自1998年以来，根据双频GNSS测量结果计算出的全球电离层图（GIM）已被广泛用于监测电离层以及在“大地测量学”中提供电离层校正。这项工作致力于全面研究时间分辨率对GIM性能的影响。已将具有较高时间分辨率和精度的IGS GIM的一个半太阳周期（UPC-IonSAT一小时一小时的时间分辨率Rapid GIM，又称为uqrg）作为基准，将其下采样到所有可能的子每日时间分辨率。通过直接与来自Jason高度表的大洋区域外部垂直总电子含量（VTEC）测量结果进行比较，评估了所得GIM的性能。为了对涉及的GIM进行完整的评估和分析，在一个以上的太阳周期中也考虑了地理位置，太阳和地磁活动的影响。此外，为了在更短的时间分辨率下具有清晰的视图，并进行了更准确的评估，2015年在大陆地区的两个冬至和两个春分日也进行了基于GIM代未使用的外部GNSS测量的dSTEC测试。评估表明，在低纬度和高太阳地磁活动下，具有不同时间分辨率的GIM之间的差异变得更加明显。结果还表明，时间分辨率小于或等于60分钟的GIM的准确性在2002年至2019年期间是一致的，并且比其他时间分辨率较低的GIM更为准确。因此，高分辨率（包括15、30，