GPS jammers send out a radio signal that’s the same frequency as the satellite signal. Since GPS satellite signals are weak, a GPS jamming device that puts out approximately 2 watts is sufficient to disrupt a GPS signal in a vehicle that’s approximately within 10 feet of the device. This leaves the in-vehicle system unable to establish its position and report back to a GPS tracking center, where the vehicle is registered.
There are also fears that terrorists can use these devices to disrupt air traffic and cause severe safety and economic damage to the US. More powerful jammers could disrupt GPS signals in close proximity of airports, causing safety concerns.
Our military overseas use GPS extensively to record their position as well as the position of the enemy. With GPS jamming devices in the hands of our enemy, U.S. and allied forces can be severely impacted when launching ground and air-strikes.
Walid Damouny on 20 Feb 10"The water content of leaves, their thickness, their density and other properties can now be determined without even having to touch them. A team of researchers from the CSIC Institute of Acoustics and the Agri-Food Research and Technology Centre (CITA) of Aragón has just presented an innovative technique that enables plant leaves to be studied using ultrasound in a quick, simple and non-invasive fashion."
