By Here is some more details about the jamming of GPS devices by the North Koreans:
A U.S. military reconnaissance aircraft made an emergency landing during annual South Korea-U.S. military exercises in March when North Korea jammed its GPS device, it emerged Thursday.
According to a report the Defense Ministry submitted to Democratic Party lawmaker Ahn Kyu-baek of the National Assembly’s Defense Committee, the RC-7B took off from its base at 8:30 p.m. on March 4 but had to make an emergency landing about 45 minutes later due to disruption of its GPS functions by jamming signals transmitted from Haeju and Kaesong in North Korea at intervals of five to 10 minutes that afternoon.
The jamming signals also disrupted the GPS devices of coastal patrol boats and speed boats of the South Korean Navy. Several civilian aircraft in the Gimpo area were also affected.
The North deploys vehicle-mounted jammers that can disrupt signals within 50-100 km and is reportedly developing a jamming device capable of disrupting signals more than 100 km away. [Chosun Ilbo]
So how long does anyone think these GPS jammers would last during a conflict? It seems like these devices are more or less there to annoy US forces as well as probably be a test platform for the Russians who gave them these devices in the first place.
1:00 am on September 10th, 2011 1
Why aren’t we trumpeting the fact that jamming is an act of war? The nKs are clearly committing an act of war and we should be shouting that from the rooftops so we can get more international pressure against them.
1:02 am on September 10th, 2011 2
Maybe we don’t want to draw attention to the vulnerability of our GPS devices, which can be disabled by jamming from the ground.
5:18 am on September 10th, 2011 3
Two words: Frequency hopping. The only way to disrupt such a signal, whose sequence would be determined by an algorythm or key which will be changed every few hours or as needed, would be to create spectrum-wide interference, thus disrupting their own coms. The technology is there. It’s just a matter of implementing it.
5:28 am on September 10th, 2011 4
That makes no sense to me.
I don’t know how fully GPS is integrated into aircraft’s basic flight systems today, but when I worked on aircraft in the pre-GPS days, they all had several redundant navigation systems and wouldn’t have to declare an emergency due to the loss of any one of them.
They probably misreported a general mission abort and return to base as an emergency landing.
8:45 am on September 10th, 2011 5
#4
Yes, I thought so too. But wouldn’t be in their advantage to make the North think they should invest more in this technology instead of another? It’s not a new trick.
9:03 am on September 10th, 2011 6
JoeC and Teadrinker, my thoughts exactly.
12:01 pm on September 10th, 2011 7
Buy all the GPS jammers you want.
http://www.jammer-store.com/gps-blockers-jammers.html
The one at the bottom for $119 that plugs into a cigarette lighter to disable tracking systems on your vehicle is only $20 in Hong Kong.
One can build/buy a suitable RF amp for a few tens of dollars. Run some 52 ohm cable and a piece of tuned wire over a ground plain on the end for an antenna and you can shut down local (or farther) navigation.
Put it all on a Styrofoam RC airplane that flies in a big circle up in the sky and take out the whole grid square… and maybe the surrounding ones as well. Shell out a couple thousand dollars and have 10 backups.
Keep in mind, the GPS satellite only transmits at 50 watts… and it is 20,000km away.
I think I could build a Styrofoam plane covered in enough solar cells that it could stay up indefinitely AND power a transmitter with a downward pointing jamming signal (so it could maintain position using its upward-facing antenna).
Do it on a budget with a hydrogen-filled balloon.
Etc.
I can dream this stuff up faster than anyone will give me a lab full of graduate students and a modest expense account.
Anyway, as a bonus, you can shut down everything which lazily… and, perhaps foolishly… relies on the GPS timing signal.
Nothing important, mind you… just little things like cellphone tower handoffs, medical equipment timing, timestamps on stock trades, power station wave synchronization, etc.
Sleep tight.
On a good note, I think I could make a jam-resistant (proof?) GPS using a sphere containing highly-directional GPS antennas with synchronized receivers (or a multiplexed receiver?) which fed the signals into a high-speed computer which could easily identify the jamming signal and its direction. Much like noise-cancelling algorithms for audio, one should be able to remove the jamming signal from the final data stream.
…at least in theory.
4:36 am on September 11th, 2011 8
Reuters in Canada says an anonymous US defense official denied that any plane was forced down by GPS jamming.
2:31 pm on September 11th, 2011 9
Ha Ha #1 I like your comment for two reasons.
1. Isn’t there is only a cease fire signed by both sides?
2. What is it called when one nation collects signals intelligence on another nation?