前マイケルから聞いていたけど、GPSは簡単にジャミング出来るらしい。かなり軍はGPSに頼っている部分もあって、結構問題になっているみたい。 From David Farber's IP
Wall Street JournalU.S. Military's GPS Reliance Makes A Cheap, Easy Target In recent months, the Pentagon has stepped up orders for precision-guided bombs that use GPS technology. The Pentagon could use such bombs in an invasion of Iraq to target Iraqi military installations with pinpoint accuracy. However, these precision-guided bombs may be vulnerable to GPS jammers. At the Paris Air Show in 1999, a Russian company called Aviaconversia demonstrated a 4-watt GPS jammer. The jammer weighed about 19 pounds and was capable of denying GPS reception for more than 100 miles. Many such jammers are available through the Internet for as little as $39.9. That has caught the attention of military officials and politicians alike. "We believe Saddam Hussein has GPS-jamming capability and that he will use it," said Rep. Joseph Pitts, the co-chairman of the Electronic Warfare Working Group. The members of this group include 25 congressmen who have been studying GPS vulnerability, among other issues. "While we do not know the extent of our vulnerability, there is evidence to suggest that GPS jamming can significantly inhibit precision targeting," Mr. Pitts added. While jammers can interrupt the commercial signal, the military signal is configured in such a way so as to make it difficult to interrupt. But the problem is that the military uses the commercial signal to track the military signal. Some research is on to come up with a technology that allows direct access of the military signal by aircrafts. Currently, increasing the signal power is the only solution. Such efforts are under way and the Air Force is planning three stages of upgraded satellites over the next 10 to 15 years.