GPS-based timing system for LAMOST | |
Xinqi Xu; Gangping Jin | |
2003-02-01 | |
Source Publication | Large Ground-based Telescopes |
Volume | 4837 |
Issue | 4837 |
Pages | Vol.4837 63-70 |
Conference Date | 2002-8-22 |
Conference Place | Hawaii USA |
Funding Organization | The International Society for Optical Engineering |
Publisher | SPIE |
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. |
Keyword | Gps Real Time Time System Utc Nts |
Subject Area | 郭守敬望远镜(lamost) ; 自动控制 |
Document Type | 会议论文 |
Identifier | http://ir.niaot.ac.cn/handle/114a32/358 |
Collection | 会议论文 |
Recommended Citation GB/T 7714 | Xinqi Xu,Gangping Jin. GPS-based timing system for LAMOST[C]:SPIE,2003:Vol.4837 63-70. |
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