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Old 23-02-2010, 15:29   #1
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GPS Security Issues

Interesting article I just came by regarding GPS and how easy it is to disrupt it. Donít throw away your sextant just yet.

BBC News - Sat-nav systems under increasing threat from 'jammers'
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Old 23-02-2010, 17:08   #2
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No worries, darling - if they jam our main one, we still have the hand-held as a back-up ...

You may consider posting this link into the 'time to buy the sextant' thread, much as I think it will not help some sextant skeptics to see the point.

LOL
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Old 23-02-2010, 17:11   #3
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Your GPS is fine - waters you travel - another..
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Old 23-02-2010, 19:10   #4
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Quote:
Originally Posted by barnakiel View Post
No worries, darling - if they jam our main one, we still have the hand-held as a back-up ...

You may consider posting this link into the 'time to buy the sextant' thread, much as I think it will not help some sextant skeptics to see the point.

LOL
b.
Am I understanding you correctly, that you imply they will jam your specific GPS unit? If that is what implied by saying you can use the hand held one, then you need to understand how GPS works. They donít jam the specific unit they pollute an area with a more powerful signal on the same frequency the GPS signal is sent on, and you can have as many receivers as you want all of them will show the same junk.
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Old 23-02-2010, 19:15   #5
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For cruisers, the potential problem is very minimal.

Future GPS units could be built to detect a spoof. Future units could still be jammed, but not spoofed. Its not just a very stable frequency that is used to measure shift in frequency caused by the Doppler shift that comes from the satellites. There is other information in the satellite signals that I doubt some boy hackers could ever emulate...especially it was to be encrypted. They would then have to break the codes (which could be changed) and go into the GPS chip manufacturing business....which I doubt would ever happen.

It may become a problem in the short term but not in the long term.
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Old 23-02-2010, 19:20   #6
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I thought it was a blonde joke...
Don't even bother posting it on the sextant thread. People only hear what they want to. But, yes, relying on any one form of navigation is not a good idea!
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Old 23-02-2010, 19:21   #7
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The US military jams GPS signals during excecises on a regular basis. In the US this is announced in Notices to Mariners and Notices to Airmen well beforehand. Generally the area in question is fairly small. I would not be surprised that other military's do the same. In area of the mouth of the Neuse river in the Pamlico sound this happens on occasion as there are several military exercise facilities nearby. On one occasion my GPS position suddenly jumped 11 miles. Fortunately I was not underway as my autopilot would have been very confused.
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Old 23-02-2010, 19:23   #8
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I am ALWAYS telling Himself to keep the marmalade away from the GPS... maybe now he'll believe me!
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Old 23-02-2010, 19:30   #9
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Shouldn't someone call a moderator? Marmalade isn't jam!
Yes, when driving with gps in remote areas of montana for instance, you can pretty well tell where military instalations like missle silos are.
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Old 23-02-2010, 20:21   #10
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Quote:
Originally Posted by Captain Bill View Post
The US military jams GPS signals during excecises on a regular basis. In the US this is announced in Notices to Mariners and Notices to Airmen well beforehand. Generally the area in question is fairly small. I would not be surprised that other military's do the same. In area of the mouth of the Neuse river in the Pamlico sound this happens on occasion as there are several military exercise facilities nearby. On one occasion my GPS position suddenly jumped 11 miles. Fortunately I was not underway as my autopilot would have been very confused.
I thought Clinton put a stop to this selective availibity issue while he was Pres.
http://geography.about.com/library/weekly/aa050400a.htm

Criminal intent to disrupt, what the article was about, ia indeed a valid concern.

So many police, and emergency vehicles use GPS that I think it unlikely that the fault is with the GPS system.
In addition, GPS is an option in cars, the trucking industry uses it for routing trucks, airplanes use it for navigation.

The USGC has reported that some TV atennas create interferance. Perhaps this is the cause.

Please note that your handheld receives the same satellite signal as your main GPS unit. If there is a difference in the display it is the unit and not the signal.
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Old 23-02-2010, 20:41   #11
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Yes, turning off SA has made ordinary gps much more accurate and top of the line $20000 units able to give aircraft lower minimums than any other instruments, so long ast the signal is "good". As you will see in the article you referenced, the military first determined that they had the ability to jam small and local areas when desired before they gave the go ahead to turn off SA. SA was a worldwide inaccuracy built in for all but military units that is no longer because they can just mess up areas that they are concerned about when they are concerned about them. And they do.
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Old 23-02-2010, 20:45   #12
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As I understand it "Selective availability" is a large area phenomenon. What I experienced was probably pretty localized and lasted only about 10 minutes. Locals have noticed that they have similar problems when EA-6Bs (electronic warfare aircraft) are operating in the area. There are a couple of bombing ranges nearby. Other electronics does funny stuff when these things are flying as well. I didn't notice any planes at the time but I wasn't looking for them. The area we boat in is an aircraft restricted area and entry by aircraft is prohibited except by permission of the US Marine Corp so it is not an aircraft navigation problem. With respect to trucks and cars I hope that people are looking at the road, not the GPS navigation unit.
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Old 23-02-2010, 21:01   #13
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Actually, a US civilian CAN apply for military GPS authorization and use the military channels (and equipment that makes use of them) which are less likely to be jammable. Some folks in blue suits will be asking questions of your neighbors if you don't already have a security clearance, but you might just get one.

But as many spooks will point out, anyone who wants to run a jammer with any great power for any reasonably long time period, is going to find out what the business end of an "anti-radiation" missle looks like, pretty quickly. There are plenty of folks who can invoke a world of pain on GPS jammers.
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Old 23-02-2010, 21:06   #14
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It's when the military are doing it, which they do regularly around ops and instalations, that it can mess you up. But ussually small areas and for short durations and if you check these messup areas and times are published in the notice to mariners or notams for pilots.
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Old 24-02-2010, 09:55   #15
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Quote:
Originally Posted by Nikday View Post
Am I understanding you correctly, that you imply they will jam your specific GPS unit? If that is what implied by saying you can use the hand held one, then you need to understand how GPS works. They donít jam the specific unit they pollute an area with a more powerful signal on the same frequency the GPS signal is sent on, and you can have as many receivers as you want all of them will show the same junk.
I understand what you say and what the article claims. I know this is only one of multiple reasons why the GPS is the thing, but should not be the only thing.

My comment was to mean that if you post this (article link and info) in front of people who claim that the sextant is an artefact of the past and that the best back up for a GPS is ... to have two units onboard - they will laugh you off. Sad but true.

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