Subject: [NEXTEL-1] Super-Radar, Done Dirt Cheap

From: [email-masked]
Date: Wed, 15 Oct 2003 18:21:19 -0400

SCIENCE & TECHNOLOGY 

Super-Radar, Done Dirt Cheap

A radar system that uses
 ubiquitous cell-phone signals is on its way 

October 20, 2003 

Any technology can be a two-edged sword. Cell phones are a good example. They're
clearly a great convenience, even a life-saving tool during natural disasters and
medical emergencies. And they should save many more lives under the Federal
Communications Commission's enhanced 911 mandate, which requires that cell phones
relay their precise locations to 911 operators.

Yet some people are appalled that their cell phone will always give away where
they are. That makes it possible to compile a "road map" of a user's movements. So
imagine the outcry when privacy worriers learn that cell-phone systems can be used
to locate and track a car, boat, or plane -- even if no one inside is carrying a
wireless phone. But outcry or not, the technology seems certain to be deployed,
given its myriad civilian and military applications.

The technology is called Celldar, from "cellular" plus "radar." Under development
since 1997 at Roke Manor Research Ltd (SI ). in Romsey, England, it differs from
conventional radar in several key respects. When radar tracks planes for air
traffic controllers -- or maps the surface of Venus from a space probe -- the same
set of equipment both sends out radio signals and picks up the returning echoes.
So computers can easily calculate an object's distance and relative size based on
how long it takes the returning signals to bounce back and how strong they are.

In contrast, Celldar takes a so-called passive approach: It watches and interprets
how signals from cell-phone base stations interact with objects such as cars,
trucks or planes. The hardware required for this is much simpler than existing
radar systems. A Celldar prototype built in 1999 consisted of a PC and the insides
of two cell phones, and cost just $3,000, says Peter Lloyd, head of Roke Manor's
Celldar program. The flip side is, the signal-processing software is complex: It
must allow for the varying travel times for signals between two or more cellular
base stations and a Celldar receiver, as well as the times from the different base
stations to the target. Lloyd says Roke's clever program is based on "$10 million
worth of expertise in writing software" for cellular systems and military radars.
One big plus to the military: passive radar systems are invisible to anti-radar
weapons because they don't have their own transmitters.

Celldar's implications are exciting -- but also troubling to some. Even though the
technology can't be used to identify cell-phone users, since it "sees" only radio
waves echoing off hard surfaces, it and similar approaches are evolving quickly.
In addition to Celldar, which is sopping up $1.5 million a year for development, a
dozen other passive-radar projects are under way in the U.S., Europe, and Asia. As
the technology bears fruit, it should give the world's police and homeland
security agencies new tools for monitoring shipments of illegal weapons and drug
smuggling operations. Highway officials could gain a detailed window on traffic
flows, helping them to minimize congestion. But because passive-radar systems
could be cheap enough for hobbyists to buy -- or cobble together themselves -- the
technology could also become the next fad among people who own police-radio
scanners or who enjoy snooping on their neighbors' comings and goings.

This month marks something of a passive-radar milestone. In late October, Roke
will show off the latest Celldar system to officials of Britain's Defense Ministry
at an army exercise on the Salisbury Plain. During the field maneuvers, Celldar
will detect the movement of ground vehicles and determine whether cell-phone
signals are bouncing off a tank, truck, or armored personnel carrier.

Also in late October, radar researchers from around the world will gather in
Seattle to discuss recent advances, including passive systems that use FM radio or
TV broadcasts instead of cell-phone signals. The invitation-only meeting will be
hosted by John D. Sahr, a University of Washington electrical engineer. Since 1997
he has operated a passive-radar system unshrouded by military secrecy. It
harnesses an FM station's signals to study particles in the ionosphere -- the top
layer of the atmosphere, over 300 miles up. Sahr decided to go with passive radar,
he says, "because it's incredibly cheap" -- $20,000 vs. $25 million for a
comparable active system. "You could probably do an amateur system for under
$5,000," Sahr adds. A system for small airports might cost as little as $15,000.
That's important because of the 5,280 public airports in the U.S., only about 300
currently have radar.

STRONG SIGNALS

Lockheed-Martin Corp. (LMT ) is perhaps the best-known passive-radar champion, but
others include Avtec Systems, Dynetics, and ONERA, the French counterpart of NASA.
Lockheed-Martin's system is dubbed Silent Sentry. Last fall, in a demo for the
U.S. Air Force, a third-generation Silent Sentry radar tracked all the air traffic
over Washington, D.C., by picking up FM and TV echoes. Because FM and TV
transmissions are more powerful than their cell-phone cousins, Silent Sentry can
detect planes as far away as 135 miles, roughly 10 times the reach of an
individual cell-phone tower.

However, because cell-phone towers are scattered far and wide in many countries,
an airborn Celldar system "could covertly monitor a whole country" by flying along
its borders, says Lloyd. At the Seattle meeting, Roke Manor and British aerospace
giant BAE Systems (BAESY ), which signed on as a Celldar partner in July, 2002,
will reveal details on their progress toward systems for small robot spy planes as
well as Airborne Warning & Control Systems (AWACS). With BAE on board, Lloyd
declares, "we could field an AWACS model in two years."

That claim prompts some skeptical head-scratching by Benjamin J. Slocumb, a senior
research engineer at Numerica Corp., a small Fort Collins (Colo.) defense
contractor that develops advanced target-tracking algorithms. A receiving antenna
that's moving, he says, "injects a whole bunch of difficult problems" in
collecting and processing cell-phone echos. But Roke's Lloyd stands firm: "We'll
show results in Seattle that are seven times better than [past studies] have said
is possible."

Despite Celldar's military potential, Lloyd predicts the first applications will
come in the civilian sector. He says transportation officials are eager to use
Celldar to monitor road traffic because it would avoid the expense of installing
either sensors in roads or TV cameras overhead. And police cars equipped with
Celldar could follow a car driven by a suspected crook or terrorist from a safe
distance, without danger of being seen.

TRACKING MADE CHEAP

Celldar might also provide an alternative to the global positioning satellite
(GPS) systems now being explored by insurance companies and governments for
monitoring vehicles. Their goal is to set premiums individually, based on how much
and how fast each car or truck is driven -- or to levy a road-use toll determined
by the distance a vehicle travels, over which types of roads, and at what times of
day. In Ireland, AXA Insurance is testing a GPS gadget called Traksure. It
continuously checks a car's speed and location, then compares that data with the
local speed limit, obtained from digital maps. But Celldar might do the job more
cheaply.

And it might support schemes by Oregon and other states regarding "pay-for-use"
road taxes. Many transportation experts assert that taxing actual driving
distances would be a more equitable way of funding highway upkeep than today's tax
on gasoline and diesel fuels. That's why the European Commission wants every
vehicle in Europe to be fitted by 2010 with a black-box device that can be tracked
by satellite. Germany is now testing such a system on trucks, and Britain plans to
require it on trucks by 2006.

Once the passive-radar cat is out of the bag, there's even a chance it could
evolve into a means of tracking people on the street. "But there'd be a lot of
technical challenges," because the human body is a poor reflector of radio
signals, says Shawn M. Herman, a researcher at Numerica whose 2001 PhD thesis was
on passive radar. Still, classified research is under way in Europe to create a
hybrid surveillance system, using both passive radar and images from the TV
cameras that now monitor many urban intersections and streets, airports, and other
public places. Suspected terrorists and other bad guys could then be watched more
closely.

The Big Brother implications of all this might unleash a massive public backlash.
But just as plausibly, people may decide to put up with technology's double-edged
sword to regain a measure of the security they have lost. 

By Otis Port in New York

http://www.businessweek.com/magazine/content/03_42/b3854113.htm

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