This is what we've been trying to tell people in the U.S. for years with regard to LORAN as a back-up for GPS. It looked like we finally turned the corner in 2009, only to have the new administration kill LORAN and eLORAN. At least the UK has the good sense to deploy eLORAN

Ok, I got the frequency wrong but my point which is being missed stands. You may get a transmitter but how do you aim it reliably at a moving target for any length of time? You could put the transmitter in the car but most comments on jamming seem to be impractical. It would soon be seen that the signal was lost, a quick check to see why and then that would be it over. Still much ado about nothing.

No, GPS doesn't run on the 2.4GHz band. That would be plain insane, given the amount of unregulated traffic that lives there - everything from WiFi to baby monitors. Nothing would ever be able to get a satellite lock. GPS runs on 1575.42 MHz with a secondary signal on 1227.60 MHz, nowhere near 2.4GHz. A badly designed 2.4GHz device MAY radiate harmonics that interfere with the secondary signal though.

is that there's are two commercial services - Public Regulated Service (PRS) and Safety of Life Service (SoL) - that provide robustness against jamming and can detect attempts to misdirect.

50 dollars for the software simulator and 40 dollars for the jammer. this is pretty major news. it totally destroys those ankle bracelets judges love to force on people in place of jail time.

As SatNav uses 2.4Ghz, its easy to jam temporarily but a moving vehical would be out of the jam signal in a few minutes. Even using a 24db dish or Yagi pointed at a moving target, its a bit much to hope you could achieve jam status for long enough to trouble any single user. Much ado about nothing.

Prisoner tracking, I like that. I was about to order a 40 dollar jammer but methinks I'll look for a better one that allows the fake coordinates. I'm certain it would pay for itself in a week.

I've been saying the same thing for years - I used to work in the sat-nav industry and it's all too easy for far less than £50 to completely jam a GPS signal - in fact it can be done for about 10p if you're only interested in blocking the signal on your own device - so all those using this technology for prisoner tracking, vehicle mileage tracking etc. better wise up... Far better to track by mobile phone cell area - less accurate but also harder to attack....