Ultra-wideband makes waves
- By Bryant Jordan
- Apr 17, 2000
Finding a needle in a haystack isn't child's play anymore, thanks to X-rays,
radar detectors and metal detectors. But how about finding a person behind
a wall of a burning, smoke-filled building? Or pinpointing the location
of a lost soldier in a foggy valley?
Those are some of the government uses of ultra-wideband technology that
its advocates envision. Assuming talks between industry and the Federal
Communications Commission ultimately end with the go-ahead to sell ultra-wideband
operating products, the public may find the technology arrives none too
soon.
The public airways are already jammed with thousands of signals from
commercial and government broadcasts via TV, radio and satellite, to shortwave
radios and cell phones. Ultra-wideband will add to the noise even while
it operates across the frequency spectrum but without, say its advocates,
further crowding or interfering with existing signals (see related story).
Most people agree that the technology, once unharnessed from federal
regulations designed to safeguard the integrity of broadcast frequencies,
will revolutionize communications.
Current bandwidth limitations will no longer restrict the amount of
signals that may be broadcast, making ultra-wideband an excellent technology
for supporting wireless local-area networks that can transmit data, voice
and video.
Time Domain Corp. will soon be demonstrating a wireless tactical operations
center for the Army's Space and Missile Defense Command. Such capability
would free a deploying unit from the wires and cables it must rely on,
said Kevin Davis, business development manager at Time Domain.
Ultra-wideband can also be used to build sensors that track people and
objects to within a few feet of their exact locations, according to Robert
Fontana, president of Multispectral Solutions Inc.
Fontana said his company produced an ultra-wideband "geolocator" about
two years ago for the military. With it, officials were able to track the
soldier's exact location from about a kilometer away. Though such tracking
can now be done using satellites, ultra-wideband technology has a major
advantage: Successful use is not dependent upon daylight and clear skies,
according to Fontana. To date, the technology has found application mostly
as radar.
The pulses, bounced back and interpreted by the transmitter, produce
images far more precise than traditional radar, which relies on high-frequency
radio waves. Engineers are using the technology to determine the soundness
of bridges by looking for structural weaknesses. Archeologists use it to
look into the ground before sticking in a shovel. The Army and Air Force
use ultra-wideband radar systems in setting up perimeters and detecting
land mines.
The FCC, which is charged with safeguarding the integrity of radio frequencies,
is studying ultra-wideband to determine its potential for disrupting other
communications.
John Reed, senior engineer with the FCC's Office of Engineering and
Technology, said the military already uses some ultra-wideband systems that
transmit over GPS frequencies, apparently without problems.
how it works
Cutting through the noise
Think of the airwaves as tens of thousands of multilane intersecting highways
with the traffic communications signals to match.
The government regulates the airwaves in much the same way it regulates
traffic, and for the same reason: to avoid chaos and disaster. Everyone
operates in specific frequencies their lanes, so to speak and if everybody
obeys the rules of the road, then traffic moves safely and smoothly.
Ultra-wideband lets you to drive in everyone's lane regardless of flow,
direction or density because instead of cruising along like the others in
a specific frequency, you're driving the equivalent of a bullet. Your signals
reach receivers in short, fast bursts or pulses. Each pulse carries a unique
signature that enables it to be picked up and interpreted by receivers.
Because data is transmitted in pulses, only microseconds apart, they can
cross other frequencies without disrupting them.
"The narrower the pulses, the more spreading you have [across the spectrum].
That reduces the potential [for] interference with other frequencies," said
John Reed, senior engineer at FCC's Office of Engineering and Technology.