CHEN Hong-qing1, WANG Zhen-wei2
(1. National Time Service Center, Chinese Academy of Sciences, Xi′an 710600, China;
2. Tsinghua University, Department of Electronic Engineering, Beijing 100039, China)
Abstract: It is revealed that there are quite a few different definitions and explanations for GPS system time among various time-service specifications in China. The clearer and more comprehensive interpretation on the GPS system time is given, which may be useful to standardization and application of the combined PNT(positioning, navigation, time-service) for BeiDou and GPS.
Key words: GPS system time; system time; time of week(TOW); week number(WN); coordinated universal time(UTC) 
