to jam GPS signals. I'm not an expert on GPS operations but there are a lot of them here in Colorado Springs. I've discussed this issue with some of them.

I've read of some really small prototype jammers but they reportedly have a limited range in practice. If you want to jam over a substancial area, then you need quite a bit of power, and radiating that amount of power makes for a dandy target for a anti-radiation missile like the HARM.

In addition, JDAMS has an inertial navigational capability built in as a backup to GPS. It's not quite as accurate as GPS guidance (30 meters CEP verses about 13 meters with GPS), but still pretty good.

There's also another alternative that I don't think approprate to discuss here that may negate the effects of GPS jamming. The technique, as it was explained to me, is cheap, simple, and effective.