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SECURITY TECHNOLOGIES OVERVIEW 5 microchips (ânanoblocksâ) that can carry many bits of product identification data unique to a particular item in a way that is similar to a car's license plate. Advantages of chipless tags are their small size and low cost (1â5 cents per tag). Disadvantages are the short read range and low data capacity. Chip tags, on the other hand, have high data capacity with read, write, and erase capability and a high reading range but are expensive (50 cents to $5 per tag). The tags themselves are generally small, but the associated antennas are large. Finally, Jotcham offered some thoughts on the problem of finding, in an urban setting, an individual who doesn't want to be found. He proposed three steps for finding such an individual: the elimination of cover; use of unique characteristics of the individual; and looking for an environmental fingerprintâthe effects of the individual on his environment. NETWORKED SENSORS FOR THE BATTLEFIELD Michael Kolodny noted that the Army is moving toward fast, lightweight, smart forces that will trade armor for information. The Army is attempting to develop a family of high-fidelity, affordable, multimission, integrated sensors that will provide near-real-time, high-resolution, âin-the-mudâ close-up information and a common operational picture to forces at all levels. The sensors will be deployed in clusters or networks that will require sensor fusion at the node and network levels, robust communication links, self-configuring and self-healing ad- hoc networks, and decision support tools. Five technology areas are key: ⢠Acoustic/seismic sensors that could detect and identify vehicles, helicopters, and the like and provide cueing for imagers (there are serious issues with triggering by spurious noises); ⢠Magnetic sensors that could detect vehicles and small arms (tanks can be detected at 50 to 500 meters, rifles at 2 to 17 meters); ⢠Infrared imagers for target identification; ⢠Radars as moving target indicators; and ⢠Radio frequency (RF) energy sensors to detect unintentional RF emissions (e.g., engine noise) as well as intentional emissions (e.g., detection and classification of radio signals). Fusion of all of the signals from these sensors will create a network that is more than the sum of its parts. The sensor network should degrade gracefully when individual units fail. Current programs are aimed at higher-cost (>$100 each), more capable sensor nodes but there is a desperate need for disposable sensors that could provide human detection capabilities in confined urban settings such as buildings, tunnels, and alleys. Urban warfare is the most difficult problem; most people in the world live in cities. The Army's vision is for acoustic, magnetic, or seismic nodes (or very low-cost imagers) costing approximately $5 to $10 each that will require minimum communication bandwidth and power, because the more traditional form of RF devices probably will not be effective in these confined terrains. There are pacing issues regarding the timing of the sensor network communications, and the system must be resistant to jamming. Kolodny believes nanotechnology can contribute here by reducing size, thereby improving covertness. So far, the Army is focuing on commercial, off-the-shelf technology, because the design must be mass-producible. Low- power algorithms will have to be packaged into a modest-performance processor. The Army is evaluating a form of smart dust funded by the Defense Advanced Research Projects Agency (DARPA) that consists of a solar- powered chip (4.8 mm3 displaced volume) combined with acceleration and ambient light sensors and bidirectional communications. GPS-based systems are probably not viable. Major challenges include cost/size reduction of integrated microelectronics (wireless networks and filters for communications; large number of sensor arrays; high-frequency components; and
