Research On The Establishment Of UTC(HUST) Local Time And Time Synchronization

Huazhong University of Science and Technology(HUST) is currently being carried out in the construction of precision gravity measurement infrastructure(PGMF). Precision gravity measurement is an indispensable means to obtain the basic data of the earth's mass variation. It is of great scientific significance to build the research facilities of precision gravity measurement for solid earth, global environment and so on. Because the distribution of the gravity field varies with space and time,in order to analyze the gravity field data of different instruments at different locations and different time, it is necessary to establish a unified time standard for all measuring instruments. The establishment of a unified time standard to a large extent depends on the time synchronization and other related technologies. Therefore, it is important to establish a unified time standard, and to carry out multi node time synchronization based on the time standard.In this paper, we introduce the preliminary work on local time establishment and time synchronization in the optical frequency standard laboratory of Huazhong University of Science and Technology(HUST). First, we use a SR620 and an AOG110 as well as the Lab VIEW to realize the frequency steering of an active hydrogen maser towards a cesium beam clock by measuring frequency difference and automatic feedback compensation technology, and Finally obtain a frequency standard with the long-term stability of 3.7 ×10-14@6day. Second, the GNSS time frequency receiving system was set up, and the local clock was traced to the Coordinated Universal Time(UTC) and other time scales in the method of GPS common view. According to the remote comparison, the local hydrogen maser and cesium beam clock are calibrated and their performances are basically in accordance with the nominal. In this way, a traceable local time scale UTC(HUST) based on the reference of cesium clock and the GPS common view was established.After the local time standard UTC(HUST) was established, it can be utilized as the time source to synchronize the computer time. The synchronization between computer time and UTC(HUST) was realized through serial communication, while the 1PPS of UTC(HUST) is utilized as the trigger signal. The time synchronization result in Windows operating system is about 1.3ms, but the multitask operation of the system has great influence on the time synchronization process. In order to avoiding the data jitter, time synchronization experiment was done in the Linux oprerating system, and the error of synchronization is about 116 us, which basically meets the requirements of time synchronization.The work reported in this paper lays a foundation for the establishment of time frequency standard of precision gravity measurement and the development of time synchronization.