Robert Fontana disappears into a hallway. Seconds later, a small reddish blob of pixels appears and moves around a field of blue and green on a computer monitor hooked up to a shoebox-sized device. The splotch tracks Fontana's position in the building, even through the two walls between him and the technology he's showing off: a tracking and collision avoidance system that can "see" through barriers like walls (or trees) and measure a target's position, bearing and speed. Fontana, president of Germantown, MD-based Multispectral Solutions, says what's inside his shoebox can one day help keep helicopters, cars and other vehicles from ramming into obstacles like power lines or people.

Behind the device is a radio technology called ultrawideband that for decades was the province of military labs. But in the last few years, startups, information technology companies and consumer electronics giants have begun pushing ultrawideband beyond the radarlike systems the military pioneered and into applications that could transform the home. Sony and newcomer XtremeSpectrum in Vienna, VA, for instance, are both pursuing the possibility of using ultrawideband transmission to wirelessly link DVD players, stereos and TVs in home entertainment systems. In the future, ultrawideband links could distribute extremely information-rich content, endowing a home or office with high-resolution 3-D virtual-reality simulation. Ultrawideband can also zap data between computing devices up to 10 times faster than today's rat's nests of wired links.

Other potential applications include tracking objects and people to centimeter accuracy (even through walls) and ultrasensitive detectors for everything from home security systems to virtual pet enclosures. Ultrawideband tags could let robotic lawn mowers or vacuum cleaners go about their tasks without ever hitting a tree or a sofa. "We've got the most feasible technology for the George Jetson-like homes of the future," says Bruce Watkins, president of Pulse-Link, an ultrawideband startup in San Diego.

Ultrawideband, proponents say, will deliver all of this via cheap, low-power radios. And, they contend-albeit over vigorous disagreement from skeptics-it won't suffer from the interference problems that plague many existing wireless devices. "It's a tremendous new technology," says Geoffrey Anderson, vice president of Sony Electronics' Advanced Wireless Technology Group. "Ultrawideband could really be a huge benefit to the consumer market."