Facing the Realities of UWB

Your articles on ultra-wideband (February, page 20) captured both sides of the argument and painted a clear picture of key UWB issues. I thoroughly enjoyed the articles and look forward to reading more special sections in your magazine.

I strongly support any technology or system capable of improving quality of life. UWB is one such technology, and the list of future benefits is impressive. FCC and NTIA actions to expeditiously move approval through the government system appear to indicate that they, too, see enormous UWB benefit potentials.

However, in our collective zeal to promote technology and systems for the common good, we must not bypass reality. Dead bodies littering the ground as a result of UWB interference with GPS signals during a critical phase of flight is one such reality. Another civil reality is an emergency response vehicle unable to locate critically injured automobile passengers due to GPS signal loss caused by UWB transmissions.

And what about the Department of Defense? Where are they in all of the UWB discussions? I believe a good number of GPS receivers rely on first acquiring the L1 signal before being handed off to L2. It seems like military operations and national security should figure in the FCC/NTIA decision process.

Joe Dorfler
General Manager
DORS International

UWB Benefits Questioned

I read your articles in the February issue on ultra-wideband. The discussion is predominately about interference. It is always assumed that UWB has great merit, and therefore, all this effort to accommodate it is worthwhile.

Does the UWB communications king have clothes? Where has it ever been shown that UWB offers spectral efficiency?

I believe all of this activity by politicians and lawyers is due to the fact that either these people have been sold misinformation deliberately or bad information by bad engineers about the capabilities of UWB communications. Other communications approaches exist that can do anything UWB can do and also be spectrally efficient, as well as not affect GPS bands.

I refer to an article published in the January 2001 issue of Microwave Journal and hope that you consider that (1) UWB interferes with existing services and raises the noise floor, and (2) UWB communications offer neither efficient spectral overlay nor capabilities that other approaches can offer. Sophisticated lawyers and government officials can be fooled.

UWB communications is truly a rebel without much cause.

Terence Barrett

Australia’s GNSS Activity

The World Radiocommunication Conference (WRC) before last, where aviation lost out considerably, set the focus for our industry and government on frequency use. As a result of that, the following WRC, in 2000, was approached with a much more integrated policy. I think that focus will continue and that ultra-wideband will be taken seriously from the beginning.

We have had a number of meetings on the issue, and the Australian GNSS Coordinating Committee (AGCC) has set up a subgroup to follow the issues and recommend a position for Australia at the next WRC. The committee’s Website is www.agcc.gov.au. It should contain any outcomes of the subgroup.

On a separate topic, I am looking for an SBAS (satellite-based augmentation system) capable GPS receiver to do some research and development work on SBAS use in Australia. It seems that, up to now, most manufacturers have avoided going for a Technical Standard Order (TSO) for this type of equipment? Any suggestions on this would be appreciated.

Ian Mallett

Why the Omission?

We at BAE Systems Canada were surprised to note the exclusion of our company name from your listing of FMS manufacturers in the January issue (page 42). Considering the many features highlighting our products that have appeared in your publication, we don’t understand the omission–even more so, since we were the proud recipients of the Avionics Magazine Award for Systems Integrator of the Year in 1999.

In fact, we recently were successful in winning a contract from Saudi Arabian Airlines, calling for the installation of our GPS-based flight management system to upgrade 12 Boeing 747-200/300 and -SP aircraft. This system has been approved for operation on virtually all air-transport models.

Tina Verni
Manager, Marketing Services
BAE Systems Canada

Do What Parachute Riggers Do

My congratulations on a truly first rate article. I refer to your January 2001 Avionics System Design column titled, "What the Heck is XTK?" It should be required reading for every avionics display/panel designer and flight training supervisor.

Since the advent of the point-and-click age, we have become so enamored with pull down menus, etc., that we think everything should be obvious to the user. I agree 100% with your statement that "Absolutely nothing is obvious to the user."

I am a former naval aviator now working as a consultant in the avionics industry. As one who has struggled with poorly designed displays and panels in flight (try having to turn your head while tuning a radio and making an approach to a night carrier landing), I have always tried to make sure that any designs over which I have any influence are as "pilot friendly" as possible. Perhaps avionics designers should be forced to fly their designs, just as U.S. Navy parachute riggers are required to "jump" chutes they’ve packed.

John S. Barger
Universal Avionics Systems Corp.

Don’t Forget the Organizers

I read with interest the article "ATN and the Reluctance to Accept the Inevitable" in the February edition of Avionics Magazine (page 16). However, it would have been nice if there had been acknowledgement that FANS Information Services Ltd. organized the ATN2000 conference mentioned in the article.

We are now in the process of organizing ATN2001, which will take place at the Institution of Electrical Engineers (IEE) in London, Sept. 18-19, with a pre-conference tutorial on Sept. 17. We will be only too pleased to provide you with further good editorial material and a press invitation to the conference, but we also would appreciate it if you could inform your readers that FANS Information Services Ltd. organizes the conference. For more information, visit the conference Website: www.atnconference.com.

Susan Whyman
FANS Information Services Ltd.

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