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Cyber Threats Prompt Return of Radio For Ship Navigation (reuters.com)
Jonathan Saul reports via Reuters: The risk of cyber attacks targeting ships' satellite navigation is pushing nations to delve back through history and develop back-up systems with roots in World War Two radio technology. Ships use GPS (Global Positioning System) and other similar devices that rely on sending and receiving satellite signals, which many experts say are vulnerable to jamming by hackers. About 90 percent of world trade is transported by sea and the stakes are high in increasingly crowded shipping lanes. Unlike aircraft, ships lack a back-up navigation system and if their GPS ceases to function, they risk running aground or colliding with other vessels. South Korea is developing an alternative system using an earth-based navigation technology known as eLoran, while the United States is planning to follow suit. Britain and Russia have also explored adopting versions of the technology, which works on radio signals.
Cyber specialists say the problem with GPS and other Global Navigation Satellite Systems (GNSS) is their weak signals, which are transmitted from 12,500 miles above the Earth and can be disrupted with cheap jamming devices that are widely available. Developers of eLoran - the descendant of the loran (long-range navigation) system created during World War II - say it is difficult to jam as the average signal is an estimated 1.3 million times stronger than a GPS signal. To do so would require a powerful transmitter, large antenna and lots of power, which would be easy to detect, they add.
Cyber specialists say the problem with GPS and other Global Navigation Satellite Systems (GNSS) is their weak signals, which are transmitted from 12,500 miles above the Earth and can be disrupted with cheap jamming devices that are widely available. Developers of eLoran - the descendant of the loran (long-range navigation) system created during World War II - say it is difficult to jam as the average signal is an estimated 1.3 million times stronger than a GPS signal. To do so would require a powerful transmitter, large antenna and lots of power, which would be easy to detect, they add.
> the descendant of the loran (long-range navigation) system created during World War II
Nope. That was LORAN, later known as Loran-A. eLORAN is a slightly upgraded Loran-C, which was entirely post-war. They are similar in name only and worked on entirely different techniques and frequencies.
LORAN-C depends on transmission stations, a lot of which are gone (although some aren't). The US and Canadian stations were shut down in 2010. Since they have to build new stations anyways, why not incorporate improvements? There's been a lot of advances since the 1970s.
> just pump enough energy into the air- and the closer you are to the target, the easier it is
But that's just it... in the case of GPS everyone is very far from the broadcasters and it is very easy for the jammer to be closer to its target than the transmitter, and very easy to generate more power than the weak signals from the satellite.
In the case of eLoran this arrangement is highly unlikely. For one thing, your target is likely to be closer to at least one of the transmitters than you are, and the power levels are so much higher that your jammer has to be equally massive.
It is MUCH more difficult to jam Loran, even in theory.
> Why is a new version needed?
The accuracy is not high enough to avoid collisions in busy areas. eLORAN adds:
1) QOS signals so you know if a station is bad
2) dLORAN (a-la dGPS) which greatly improves accuracy
3) globally synced signals (a-la Omega) so you can use any signal as the basis for measurements against any other
4) easy identification of ground vs. skywaves
All ships use the AIS collision avoidance system. The sending ship sends a radio signal that contains information about the ship, its position (derived from GPS), and its course and speed. The receiving ship has a receiver that displays the information from nearby vessels (and its own position and course) overlaid on a chart. Without the position derived from GPS the system collapses.
Dead reckoning can give a good approximation of where the ship is, if the navigation monuments (lighthouses, etc.) can be picked out from the buildings on the shore, especially at night with thousands of of other lights on the shoreline.
The problem isn't so much running aground as avoiding collision. Picking out running lights of a ship against the background of the shore lights can be daunting. Even then it's a guess as to the ship's course and there may be several ships that need to be watched perhaps with only the mate on watch to keep track of everything.
Read about the recent collision of the USS Fitzgerald and the MV ACX Crystal.
Nate
This article discusses the improvements that eLoran offers: http://gpsworld.com/innovation-enhanced-loran/ The article lists the following key differences between Loran-C and eLoran:
All transmissions are synchronized to UTC (like GPS)
Time-of-transmission control
The ability to use differential corrections (similar to DGPS)
Receivers use “all-in-view” signals
Includes one or more Loran data channels that provide: Low-rate data messaging, added integrity, differential corrections (dLoran and/or DGPS) and other communications including navigation messages.
All ships use the AIS collision avoidance system. The sending ship sends a radio signal that contains information about the ship, its position (derived from GPS), and its course and speed. The receiving ship has a receiver that displays the information from nearby vessels (and its own position and course) overlaid on a chart. Without the position derived from GPS the system collapses.
Actually, without GPS, AIS will collapse, but not due to the loss of position signal. AIS is based on Self-organizing TDMA to manage on-air resources. Each second is divided up into 2250 time slots, which are precisely aligned with UTC seconds. The accuracy is such that for Class A beacons, this can only be derived from timing signals from the beacon's internal GPS receiver.
That said, AIS is only one tool in the arsenal. Ships also have dual radars, and if that goes bad, there's always the MK1 eyeball and MK0 ear.
I was out sailing this past weekend, and the visibility was utter shite. We passed within 2 miles of the Crystal Serenity, the largest cruise ship doing the Alaska run, and the only reason why we knew she was there was due to our radar, the fact that we heard her fog signals, her crew's chatter on the radio, and lastly because we had her on AIS. It's all about redundancy and alternate means.
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