Out in Front: Apply the Seat of the Pants

March 1, 2010  - By 0 Comments
Alan Cameron

Alan Cameron

Not “fly by,” but “apply.” As in W. Somerset Maugham’s advice to aspiring young writers: Apply the seat of the pants to the seat of the chair.

Get grounded. Confront the blank page, the typewriter, or the less preferable modern equipments (because instant electronics short-circuit orderly brain function) for a period of silence and contemplation. Above all, think. Then, and only then, communicate.

Some serious word-eating now ensues. In last month’s editorial, I faulted the Architecture Evolution Plan (AEP) GPS ground control software update 5.5C for wreaking havoc with fielded receivers, both military and civil. Website news stories that I subsequently posted bore headlines driving this misconception home.

I was wrong. Subsequent analysis by more knowledgeable and expert people has established that, yes, havoc was wreaked, but not by the software update. The deficiency resided in the factory-installed software of the respective receivers. See The System story on page 12 for details.

In my only defense, I state that I was groping in the dark. Very incomplete word, secondhand no less, arrived just as we were preparing the issue for press. No official announcement came from the Air Force during the days that followed. We understand that internal brouhaha was brewed, stern words were uttered and written, but ultimately it was determined that the fault lay in the user segment, not with ground control or vendors thereto.

We have it on good authority that the GPS Wing maintains, and will presumably continue to maintain, that the AEP update was absolutely perfect with no software glitches. But the Wing also realizes that none of the receiver manufacturers had any idea how the update was going to be implemented, as in what pages would be affected, and if there would be new data in places where it had not been loaded before.

A grudging admission emerges that there may be some ambiguity in the receiver interface control documents (ICDs), and that those may need some tightening up sometime soon.

We return to the theme of communications, in this case clear ones between the GPS Wing and the various user communities: civil, commercial, and military. For GPS to maintain its place as the world’s gold standard, there must be clear — and timely — communication between the Wing and its customers. All customers. Dual-use.

So far, there’s no No. 2 system trying harder in this regard. But why leave the door open?

A controversial suggestion: beta versions of future AEP updates could be released to a predefined subset of receiver maufacturers, who would test and report back concerning any glitches that occurred when their receivers saw the new software and simulated nav message for the first time.

Work with the customers.

I’m off to take my own medicine now.

This article is tagged with and posted in From the Editor
GPS World staff

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