European Galileo officially provided global users with the initial high accuracy service (HAS) through Galileo satellites for free on January 24, 2023. The emergence of the Galileo HAS provides the possibility of a globally stable real-time precise point positioning (PPP) time transfer that does not depend on a network. The coverage and service availability (the proportion of epochs that can support PPP solution) of the HAS, accuracy of the satellite orbit and clock offset, and accuracy of HAS time transfer were comprehensively analyzed using real-time and satellite-broadcast HAS data. Twenty-three global time links, including time-keeping laboratories, were established to assess the accuracy of time comparison using the HAS product. The results showed that the average numbers of GPS and Galileo satellites with valid HAS corrections worldwide were 9.44 and 7.95, respectively, and the average service availability of GPS-only and Galileo-only PPP using the HAS product reached 99.9% and 99.6%, respectively, in most areas. Taking post-processing satellite products from GeoForschungZentrum as a reference, the radial errors of the HAS orbit product are concentrated within 5 cm, and the accuracy of the corrected Galileo satellite clock offset was twice that of ephemeris. Further, in the 7200–12295 km-long baselines, the mean standard deviation values of HAS GPS-only, Galileo-only, and GPS/Galileo time comparison result errors were 0.19–0.29 ns, 0.13–0.24 ns, and 0.11–0.21 ns, respectively. In general, HAS time transfer is available globally.

欧洲伽利略于2023年1月24日正式通过伽利略卫星免费向全球用户提供初始高精度服务（HAS）。伽利略HAS的出现为全球稳定的实时精密单点定位（PPP）时间传递提供了可能不依赖于网络。利用实时和卫星广播的HAS数据，综合分析HAS的覆盖范围和服务可用性（可以支持PPP解决方案的历元比例）、卫星轨道和时钟偏移的精度以及HAS时间传递的精度。建立了 23 个全球时间链接，包括计时实验室，以评估使用 HAS 产品进行时间比较的准确性。结果显示，全球拥有有效HAS改正的GPS和伽利略卫星平均数量分别为9.44颗和7.95颗，使用HAS产品的纯GPS和纯伽利略PPP的平均服务可用性分别达到99.9%和99.6% ，在大部分地区。以GeoForschungZentrum的卫星后处理产品为参考，HAS轨道产品的径向误差集中在5厘米以内，修正后的伽利略卫星钟差精度是星历的两倍。此外，在7200-12295公里长的基线中，HAS仅GPS、仅Galileo和GPS/Galileo时间比较结果误差的平均标准偏差值为0.19-0.29 ns、0.13-0.24 ns和0.11-0.21分别是ns。一般来说，HAS 时间传输在全球范围内都可用。