International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / The necessity of supplying precise time information in large telemetry ground stations
and astronomical observatories is very similar. Therefore the way of solving this
problem as it is done in the Very Large Telescope of the European Southern
Observatory can be easily adopted to telemetry stations and ranges, especially when
fiber optics are used.
The European Southern Observatory (ESO) is building a new observatory in Chile for
the Very Large Telescope (VLT). This VLT consists of 4 telescopes, each of them has
a primary mirror diameter of 8 meters. the control architecture is based on
workstations and VMEbus computers. The VMEbus computers are distributed over
the whole building and are using real time operating system.
Since the availability of the Global Positioning System (GPS) the generation of highly
accurate timing signals on remote locations without the use of expensive Cesium
standards does not create problems any more. However, distribution of a timing signal
to many computer with high accuracy is an issue. The accuracy of the commonly used
IRIG B-code is not adequate if the requirements are in the 10 microseconds range.
This paper presents the design of a timing system that is adopted to the VLT. An
overview of the requirements of the Time Reference System (TRS) is given. These
requirements have been defined on the basis of experiences with the timing system of
the ESO NTT telescope.
The hardware units are described. These are a Central Time Standard, a Time
Distribution System and a VME Time Interface Module. The distribution is based on
fiber optic transmission, using a simple digital modulation that outperforms the analog
IRIG B modulation. The Time Interface Module in the computer does not only
perform the timing signal decoding but contains also user-programmable timers that
are synchronously clocked from the time source.
Presently all units of the TRS have been tested and the series production of the
distribution and the Time Interface Modules are in progress.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/608540 |
| Date | 11 1900 |
| Creators | Lange, Werner R., Ravensbergen, Martin |
| Contributors | LANGE-ELECTRONIC GMBH, EUROPEAN SOUTHERN OBSERVATORY |
| Publisher | International Foundation for Telemetering |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Proceedings |
| Rights | Copyright © International Foundation for Telemetering |
| Relation | http://www.telemetry.org/ |
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