Interesting article...
http://www.economist.com/news/international/21582288-satellite-positioning-data-are-vitalbut-signal-surprisingly-easy-disrupt-out?fsrc ="scn/tw/te/pe/outofsight"
And before anyone else makes the reference...:-P
The reason we even have GPS is because it was developed and put into place as a military tool, as such it has been provided with the necessary funding to expand and maintain the system. If jamming and other interference causes the military to switch to a system less subject to interference by others, GPS funding will dry up. I have been expecting that to happen after other country's started to place their own systems into orbit. Those country's probably know all about jamming and other risks of depending on a single system and may have their birds in orbit with frequencies in place that could jam our system, activated with a single command. Don't know if there will be any civilian access to any new systems that might replace GPS but do know that civilian use of the current GPS system would be unable to provide enough money to maintain our current system. With the current control we now have, it would not be far fetched for surveyors to be using a local navigation system that uses two bases occupying known points and those bases transmitting directly to a rover without corrections, Loran?.
jud
fattiretom,
I heard an interesting session on a talk radio station I was listening to while traveling the other day. I should have wrote down the specifics but I think the professor was from the Univ. of Texas. The experiment was to see if someone could actually take control of a GPS guide boat without the crew noticing. The story about the experiment said that they were successful in not just jamming the GPS but actually making the navigation system think that the boat was till on the correct heading. The professor was station that false signals can be sent in a local area and that the "tricked the boat into being guided on a false position and heading. Scary stuff.
I will try to look it up and see if I can find a link to an article.
I found the links to the story for the experiments for GPS Spoofing by the University of Texas...
Yacht Experiment...
Drone Experiment...
Sounds like the James Bond movie.
Dave,
It does sound like something out of a spy movie. I am not sure where all of the jamming and spoofing for GPS or even other constellations will go. It has been a topic that is getting hotter of the last 3 or 4 years. Another part in the news show talked about UT (I believe it was UT or some other group maybe)that had filed request for responses to several of our government agencies towards plans to take action towards this issue. The talking head for the news show talked like there should be some "magic" solution that could be done by throwing a secret switch somewhere. He had no ideal about how GPS works and how easy the signal can be disrupted or even how weak the signal rally is when it is being received.
No response has been received from the agencies as far as the interview I was listening to on Friday. I guess no one would really cares to hear that there is nothing that can be done.
Either way it will be interesting to hear what develops in the near future.
The James Bond movie was "Tomorrow Never Dies". That was the plot - a GPS jammer that sent a British ship off course.
This has been around for several years. Old stuff. When the Korean Airliner crashed in San Diego a few weeks ago, I posted a message on Beerleg.com to the effect that maybe some nutjob was using a GPS jammer to give false heights during landing.
Nobody seemed to notice at the time.
Some years ago, there was a United States reconnaisance drone that crashed in Iran. The Iranians claimed that they had jammed the drone's GPS guidance system and had caused it to crash by using a GPS jammer to give false heights.
Nobody seemed to notice at the time.
An RF engineer I know through the local amateur radio club is trying to straighten out the police digital voice radio for a fairly large California city. Passing the digital signals to various parts of the city requires precise time, which is provided by GPS, which in turn is jammed by truckers who wish to visit the city's ...ahem... attractions without their bosses knowing.