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Deutsche Beschreibung des Inmarsat-E+ SystemsEnglische Version der Inmarsat-E+ Seite

The Inmarsat E+ System
(Since the Inmarsat-E/E+ system has been shut down on 1.12.06 the description is for historical reference only.)

Inmarsat-E+ is an enhancement to the Inmarsat-E system. Inmarsat-E+ raises the high redundancy of Inmarsat-E even further and enables the installation of remote RCCs at low cost. Inmarsat-E+ may also be used to deliver acknowledgement information to Inmarsat-E+ EPIRBS in the future. The navtec Ltd. did the design, development and implementation of the world-wide infrastructure for Inmarsat-E+ (so called acknowledgement channel). The system consists of the follwing components.
(Run the mouse over the picture)
Geostationary Inmarsat satellites relay the distress call GPS (GALILEO in the future) deliveres position information
Land Earth Station (LES) relaying distress calls X.25 forwardes the information to (M)RCCs RCC finally rescues the people in distress Inmarsat Headquater monitors the traffic EPIRB transmits distress call and receives acknowlegment
  1. The EPIRB receives position information via GPS and transmits the distress call via Inmarsat satellites.
  2. Inmarsat satellites relay the distress call to the land earth station (LES).
  3. The land earth station forwardes the distress call not only via X.25 but also via satellite to the nearest rescue co-ordination centre (RCC). This increases the reliability and raises the redundancy.
  4. The Inmarsat satellite relay the call to several receivers :
  • The Maritime Rescue Co-Ordination Centre (M)RCC receives the call on a dedicated channel.
  • The Inmarsat Headquater (NOC) receives the call.
  • The beacon receives the call and may switch on a green light to indicate to the person in distress that the call has been received.
All this takes place in seconds - fully automaticly without any time delay. In real life there is more than one LES receiving the beacons transmission as well as there are more than one RCCs receiving the forwarded distress call.


E+ RCC Installation

The (M)RCC installation consists of a 19" rack with fully redundant antennas, redundant receivers, redundant demodulators, storage devices, printers and an alarming device for the watch officer.


E+ LES Installation

The LES installation consists of a 19" rack with fully redundant antennas, redundant GPS receivers for world-wide time synchronisation, redundant modulators/transmitters, upconversion, ocean region (OR) multiplex, storage devices, and documentation printers.