GPS-based timing system for LAMOST

Xinqi Xu; Gangping Jin

doi:10.1117/12.456726

4 February 2003 GPS-based timing system for LAMOST

Xinqi Xu, Gangping Jin

Author Affiliations +

Proceedings Volume 4837, Large Ground-based Telescopes; (2003) https://doi.org/10.1117/12.456726
Event: Astronomical Telescopes and Instrumentation, 2002, Waikoloa, Hawai'i, United States

Abstract

The control system of LAMOST telescope is highly distributed real time system, and the time base is crucial. During the motion tracking for 4000 celestial objects being simultaneously observed the alt-azimuth mount has to be driven on two axes in a servo loop to follow the motion of the objects in a timing system that has to be precise to the level of a few milliseconds. The GPS-based timing system has been developed in the lab of Nanjing Institute of Astronomical Optics & Technology (NIAOT). This paper describes a Net Time Server (NTS) that maintains the Coordinated Universal Time (UTC) derived from GPS, and distributes the time to precisely synchronize the client computer clocks across a network. The NTS is built on real time OS QNX4.25 platform. With help of a GPS receiver at hand, the NTS reaches the precision of 0.1 millisecond, and the time precision across LAN computers served by the NTS can meet the requirements for different time critical tasks in LAMOST control.

Citation Download Citation

Xinqi Xu and Gangping Jin "GPS-based timing system for LAMOST", Proc. SPIE 4837, Large Ground-based Telescopes, (4 February 2003); https://doi.org/10.1117/12.456726

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