US airlines and the General Aviation Manufacturers Association (GAMA) have reacted with concern to the approval by the US Federal Communications Commission (FCC) of the use of ultra-wideband (UWB) devices.

The US Air Transport Association (ATA) and GAMA believe UWB can cause interference with the global positioning system (GPS), which operates in the same frequency spectrum as UWB devices.

The FCC has authorised UWB devices above 3.1GHz and imposed technical limits below 3.1GHz. It believes that UWB holds "great promise" in applications ranging from radar imaging to short-range, high-speed data transmissions.

UWB uses very narrow or short duration pulses that result in very large or wide transmission bandwidths. The FCC says that, with "appropriate technical standards", UWB devices can operate in the spectrum occupied by current radio services without causing interference. Given the demands on the spectrum, UWB is seen as an efficient use of it. The FCC's full report and proposals are expected to be released next month, with UWB approval expected to result in limited use of the frequency bands by other users.

Aeronautical users of GPS have long pressed for UWB not to be approved due to its potential to cause interference. GAMA and the ATA were particularly concerned that proponents of UWB had not been required to prove its safety. ATA says testing has shown that UWB devices can create a risk to public safety by disrupting aircraft navigation systems. Aviation associations have recommended that UWB devices should not be permitted to operate in restricted spectrum bands or below 6GHz.

The US Department of Defense, however, which controls GPS, says the FCC's limited approval of the devices "continues to protect critical, spectrum-dependent military systems, including GPS".

Source: Flight International