Bin Laden and his band of Islamic Terrorists may have one more thing to worry about now. NewScientist.com reports that Unattended Ground Sensors (UGSs) are being deployed in the mountains and valleys of Afghanistan. Networks of the tiny autonomous sensors measure acoustic and seismic vibrations with enough accuracy to distinguish troops from vehicles. Target information is relayed instantly to satellites allowing a rapid response. UGSs come in a variety of forms. Some can be dropped from UAVs. Others must be implanted in the ground. An overview of one type of seismic sensor can be found here. A paper is available that describes algorithms that may be used to classify and localize the targets using UGS networks.