Consumer-grade jammers have a hard time disrupting military signals

　　Pseudo-satellite and standby inertial navigation systems mean that smart bombs and cruise missiles may reach their intended targets. The US military controls the airspace over the battlefield. But in a conflict in which pseudolites cannot be safely deployed, ground forces could go astray or misdirect their fire if they encounter a minefield of expendable, hockey-puck-size GPS jammers, each of which could disrupt the GPS signal within a one-kilometer radius. Iraq reportedly also purchased as many as 400 small GPS jammers from Aviaconversiya prior to the outbreak of hostilities in the region, although it is not known whether any of these were used.

　　"This is a serious threat," said Jim Hendershot, president of Radio Design Group. Headquartered in ore. Grants Pass, a manufacturer of GPS jamming equipment used in training.Because these small jammers can interfere with people on the ground. Soldiers' GPS receivers have no backup navigation system. They will be deprived of navigation.“

　　In August 2000, the Greek authorities unwittingly revealed the extent to which ground forces rely on GPS. The United States, Britain, and France compete for a $1.4 billion tank contract. As every country's tanks enter to show their strength, it is obvious that the United States. South British tanks can't get GPS navigation signals. Sometime later and to the amusement of Greek defense officials, reports the journal Military Review, it was revealed that French agents were remotely activating small, one-foot-high GPS jammers to disrupt the GPS signal when British and U.American tanks are on the battlefield. Such a GPS jamming strategy should not come as a surprise, given the reality of the US. As early as March 2000, the United States and Australian military carried out a joint GPS jammer locator research in remote Woomera.

　　In fact, small GPS jammers can be built by any hobbyist with a spare $400 to invest in electronic components, using plans supplied by the online hacker magazine Phrack, for example. Such devices can easily disrupt a commercial GPS signal and possibly a military GPS signal, even though the latter is encrypted with a code that changes on a regular basis. Hendershot said: "Military signals are hard to destroy, but they are still easy.“

　　That's why the military is lobbying to launch 20 new GPS satellites next year. These new satellites would transmit a GPS signal eight times stronger than the current signal, which means that any potential jammers would have to increase in size and complexity. Experts like Hendershot point out that before that, GPS was very fragile.