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Old 05 February 2008, 09:22   #11
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In that case why do the tests at sea? If the effect wanted is to send a different signal there's no need for it to be done at sea. The results can established on land.
There are a whole load of possible reasons: (1) that is where the test range is (2) this is an unpopulated area where it is not going to upset the publics' tom-tom (3) the research may well be being sponsorred by the Navy [each MoD research project that DSTL/QinetiQ undertake has a "customer" within one or more armed forces] (4) they can ignore the effects of land on the results - a flat surface is easier to interpret the results from (5) they may be doing tests on land too - but the RYA publicised it for the interest of marine users (6) there are actually some big radio antannae in the viscinity so it may be they need/want to use those existing mast [not sure if they are owned by MoD or not - but it is certainly feasible]. (7) if they want to test the range of the effects they can just keep travelling out to sea - if it is on land and they get to the edge of their field they can't go any further (8) they may (?) be testing the effects on missile guidance systems. Not sure if the sea is an official firing range or not in that area.

I am sure there are others.
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Old 05 February 2008, 09:47   #12
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That's a pretty good answer
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Old 14 February 2008, 19:16   #13
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From the RYA website...

http://www.rya.org.uk/NewsAndEvents/...gpsjam4feb.htm

"Similar trials carried out for the Government, by the MOD have already taken place in a number of areas including Lincolnshire, Wales, Scotland and Cornwall have had an effect over a range of approximately 11km. Details of the trials are "restricted", but the government has said that the trials are intended to research "vulnerabilities in a range of military applications" of satellite navigation, although is has also been noted that the Defence Science and Technology Laboratory PR team have denied that such trial are taking place! For previous trials the Coastguard have locally broadcast details of the trial with timings and a Notice to Airmen was also published at least for the trial in Portreath, Cornwall.

GPS satellites transmit two low power radio signals, designated L1 and L2. Civilian GPS uses the L1 frequency of 1575.42 MHz in the UHF band. All radio navigation systems are susceptible to interference and environmental effects, which can adversely affect their availability. Because of the low power and Ultra High Frequency GPS is particularly susceptible to interference and even hostile jamming which is why the General Lighthouse Authorities are establishing a new Enhanced Loran (eLoran) station in Cumbria, UK (coordinates: Latitude 54 54' 40.35'' N. Longitude 3 17' 14.21'' W). It is hoped that this will be fully operational by the end January 2008.

The RYA strongly advises that no single aids to navigation system should be used in isolation and that users should use all alternative means available to cross check the information received."

So keep those paper charts and sextants handy!
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Old 14 February 2008, 23:14   #14
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They should go back to Decca!!!
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Old 15 February 2008, 04:26   #15
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Why?
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Old 15 February 2008, 06:26   #16
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So keep those paper charts and sextants handy!
I always assumed thats what they were doing.. getting the crew on exercise to navigate in conditions as if there were a gps system failure.

When GB TB and the other G8 attendees were at Gleneagles, a whole zone was shut off around the area. Presumably a satellite out put can be turned off too, preventing triangulation, rather than having to jam a signal.
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Old 15 February 2008, 07:54   #17
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I always assumed thats what they were doing.. getting the crew on exercise to navigate in conditions as if there were a gps system failure.

When GB TB and the other G8 attendees were at Gleneagles, a whole zone was shut off around the area. Presumably a satellite out put can be turned off too, preventing triangulation, rather than having to jam a signal.
Not sure they will be..switching or blanking off the GPS set for training purposes happens all the time, dont need to go to such extreme lengths to simulate failure
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