Marine Link
Thursday, May 30, 2024

Hearer, Faster & Cheaper,,. Distress Alerting Via Inmarsat

By Ruth Ling, Inmarsat direct dial telephone to telex, data the most recent of these is tress alerting system than ar More than 40,000 Inmarsat ter- and e-mail. Inmarsat, the interna- Inmarsat E (the emergency posiminals, fitted to vessels of all types tional mobile satellite organiza- tion indicating radio beacon, or worldwide, provide communica- tion, is continuously developing EPIRB), designed to be a faster, tions via satellite ranging from and introducing new services, and more reliable and more precise dis-that had been available before. Another new product to have had great success is Inmarsat phone, the portable personal com munications system for business travelers. But this move into lane mobile services has not been at the expense of the maritime market in favor of land mobile services, as Andy Fuller, manager of the maritime department at Inmarsat, explains: "Inmarsat's continuing commitment to the GMDSS for high quality safety communications means that we are developing and introducing a number of new products and services such as Inmarsat E and others related to the GMDSS. These initiatives are a result of what our maritime customers tell us they need." The Inmarsat E system complies fully with the Global Maritime Distress and Safety System (GMDSS), covers virtually all the world's ocean areas, is highly reliable for both SOLAS and non-SOLAS vessels and is free of charge to users. It was developed jointly by the German government, the European Space Agency, manufacturers Nortel Dasa, Siemens and MBB and Inmarsat. Combined Technologies Inmarsat E combines the position determination of the Global Positioning System (GPS) or GLONASS satellite navigation technology with the geostationary satellite technology of thewhich have proved their reliability over many years of use by mariners and others. The use of geostationary satellites greatly increases the speed at which a distress alert can be delivered, as no time is lost waiting for a satellite to appear over the horizon.

The system features both float free buoy type EPIRBs (emergency position indicating radio beacons) for use onboard larger vessels as well as hand portable versions for yachts, lifeboats and similar applications.

Both types of terminal include a built in GPS receiver so that the position of the unit is constantly updated to an accuracy of better t h a n 61 ft. (200 m). This compares with an accuracy of about five kilometers for the best of the current emergency alerting systems. The terminals also include an Inmarsat satellite communications transmitter which automatically transnits the coded distress alert to all accessible "nmarsat satellites.

Inmarsat transmitters use the L band range if frequencies, specifically allocated for search ind rescue (SAR) maritime communications >ecause they are virtually unaffected by idverse meteorological conditions and interfernce from other L band spectrum users.

Improved power budget, made possible brough the three new Inmarsat E satellites lunched last year, leads to a much better ransfer of distress messages through the satelte. A distress signal can be triggered manully or automatically when a float free terminal i submerged. As a minimum the message will mtain the identity of the terminal and its posion at the time of the alert. This information will be transmitted via an Inmarsat satellite to an LES where it will trigger an alarm while being automatically relayed via a fixed landline connection, to a Rescue Coordination Center (RCC). Many vessels will carry an on bridge display showing the status and position reading from the EPIRB. In an emergency, crew members will have the option of triggering an alert transmission and including, via a short code keyboard, additional information on the nature of the emergency. Similar information can be input by the user of a portable terminal. Once triggered, terminals will continue transmitting for 48 hours unless de-activated manually.

Some models will also feature a search and rescue radar transponder (SART) beacon to enable rescuers to home-in using radar once they reach the area of the transmitted position. Land earth stations (LESs) operating with the Inmarsat E system are: Raisting (Germany), which covers the Atlantic Ocean East and Indian Ocean region satellites; Perth (Australia) which covers the Indian Ocean and Pacific Ocean satellites; and Niles Canyon (U.S.) serving the Pacific and Atlantic Ocean West regions. Inmarsat is currently negotiating for a fourth LES installation to provide duplicated cover in the Atlantic East and West regions. "This will give the system the added security of double coverage in every region," said Mr. Fuller. "But in fact, even now with three stations operating, there is only one small section of the Pacific without double coverage." Like Inmarsat, the LES operators Deutsche Telekom in Germany, Telstra in Australia and IDB in the U.S. — are all providing their Inmarsat E services free of charge.

Each LES is connected to its national rescue authority via a dedicated link. In Germany this Is the Bremen rescue coordination center; in Australia it is a similar RCC in Canberra and in the U.S. it is the U.S. Coast Gluard data network. These authorities will deal with an emergency themselves or pass ;he information on to an appro- Driate RCC, usually the one learest the source of the distress alert and therefore in the best position to coordinate rescue efforts. A range of Inmarsat E float free and personal portable EPIRBs is being marketed by four manufacturers: Nortel Dasa GmbH;, OHB System GmbH; Nokia; and Kreiger Gesellschaft GmbH. As an affirmation of Inmarsat's commitment to safety services, the Inmarsat E EPIRB has "real benefits over those that we've seen up till now," said Peter Goldsmith, Inmarsat's market manager for merchant shipping. "It's much faster than previous systems ... as soon as the button is pressed, there's a record of that in the RCC, rather than the ship in distress having to wait for a satellite pass, which could mean up to a couple of hours. So speed of response is dramatically enhanced." In tests carried out shortly before its introduction, Inmarsat E proved to be 100 per cent reliable in delivering a comprehensive distress message to LESs, typically within two minutes of an initial alert.

"This is a great improvement on current satellite and radio systems, which can take hours to deliver an alert," said Goldsmith. "As we have seen recently, if such alerts are not sufficiently comprehensive they often raise as many questions for rescuers as they provide answers." Goldsmith also stresses the accuracy of the position reporting. "It's much, much higher ," he said. "Earlier alerting systems were accurate only to within four or five kilometers; Inmarsat E is accurate to within 200 meters. If an aircraft is looking for a person in the water, it's like looking for a needle in a haystack. "After all, just three weeks before we launched Inmarsat E, the British yachtsman Tony Bullimore was lost in the Southern Ocean for five days during the Vendee Globe race. It's very difficult to find a hull 60 feet long in the sea, especially if it's upside down as his was ... an aircraft's pilot would be lucky to see it. When you're searching for someone lost in the sea and you have Inmarsat E, you can home right in on that person and check the accuracy of the position reporting.

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