Steel Rattler is a multi-phased project to determine the feasibility of using commercial off-the-shelf components in an advanced acoustic/seismic unattended ground sensor. This project is supported by the Defense Intelligence Agency through Sandia National Laboratories as the lead development agency. Steel Rattler uses advanced acoustic and seismic detection algorithms to categorize and identify various heavy vehicles down to the number of cylinders in the engine. This detection is accomplished with the capabilities of new, high-speed digital signal processors which analyze both acoustic and seismic data. The resulting analysis is compared against an onboard library of known vehicles and a statistical match is determined. An integrated thermal imager is also employed to capture digital thermal images for subsequent compression and transmission. Information acquired by Steel Rattler in the field is transmitted in small packets by a built-in low-power satellite communication system. The ground station receivers distribute the coded information to multiple analysis sites where the information is reassembled into coherent messages and images.