DOT cautious about ultra-wideband

The Transportation Department supports ultra-wideband, an emerging technology

for communications and positioning, but last week cautioned that more testing

is needed to ensure that UWB poses no threat to existing transportation safety

technology.

DOT submitted its position Sept. 12 on proposed rule-making by the Federal

Communications Commission to allow UWB products to operate without individual

licenses. FCC already permits the operation of some UWB devices on an experimental

basis.

UWB devices can facilitate X-ray-like imaging, wireless communications

and positioning and location. But DOT is concerned that UWB emissions may

interfere with the government's Global Positioning System, which is used

to provide aviation, maritime and military users with precise location and

timing information via radio frequency signals from satellites.

The DOT filing to FCC said:

* UWB is a promising technology that may offer significant public and

private benefits.

* Existing technologies and their users must continue to be protected

from interference, particularly those involved with safety-of-life functions

such as GPS.

* Carefully structured testing programs should determine the nature

and extent of protection from UWB emissions, if any is necessary.

"Billions of dollars of public and private funds have been spent [on

GPS and other communications, navigation and surveillance systems], and

future applications indicate that more will follow. This has not been and

should not be jeopardized by interference from other sources," the DOT filing

by general counsel Rosalind Knapp said.

Preliminary results of testing by DOT and the National Telecommunications

and Information Administration, which manages spectrum for government systems,

found that UWB emissions can interfere with GPS receivers or may be benign,

depending on the UWB parameters and on the application.

DOT also acknowledged that UWB has the potential to improve transportation

safety. For instance, ground-penetrating UWB radar could be used to examine

the condition of roadways and bridge decks, the filing said.

UWB devices may also provide a way to communicate between vehicles and

help with collision avoidance.