International Telemetering Conference Proceedings / October 22-25, 1984 / Riviera Hotel, Las Vegas, Nevada / For maritime applications of distress communications via geostationary satellites a special
method of signal processing was developed, called superposition technique. The data
frame containing the alert message is transmitted from a distress equipment repeatedly.
After being relayed by the satellite the signal is detected and improved by superimposing
the frames. Around 14 dB is the actual processing gain. Thus a distress buoy is able to
transfer a message from all over the world with high reliability by only transmitting a
power of 50 mW omnidirectionally over a slant range of about 40 000 km.
The described system, called the Distress Radio Call System (DRCS) was tested in a
Coordinated Trials Program (CTP) of 6 nations. Both in a simulation phase and in a field
test under exactly the same environmental conditions the DRCS with its superposition
technique was able to detect signals with lowest signal-to-noise-density ratio without error.
In laboratory tests using GAUSS channel conditions, a system threshold of 13 dB-Hz
could be demonstrated. In a real environment (North Cape) 15 dB-Hz was the lower limit
for error-free reception.
CCIR approved a recommendation in June, 1984 for a system operating through
geostationary satellites at 1.6 GHz being a DRCS-type with very little modifications.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/610932 |
| Date | 10 1900 |
| Creators | Goebel, Walter |
| Contributors | DFVLR - German Aerospace Research Establishment |
| 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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