Praxis Foundation asked this question several days ago:
Is anybody concerned that the GPS system can be rendered unusable by a 42dBw transmitter in an adjacent spectrum? Is it prudent to build a no-backup, global system that can be rendered unusable by a miscreant hobbyist that might not be a law-abiding American?
Praxis is talking about one of the core components of the FAA’s version of NextGen. I wrote about my concerns on the same subject at least once, here.
Yesterday, Praxis kindly posted the Aviation Week article re: USAF Decisions On GPS IIIB Could Affect FAA, which had these tidbits (Note: According to the article, Mr. Frye is the GPS III capability insertion manager at Lockheed Martin):
“We are beginning to think maybe if we go to two crosslinks, we can reduce the cost of that crosslink network, still provide most of the function, but not do some of the wonderful things we were expecting in IIIC such as supporting the integrity operations, which was an FAA certification issue,” Frye said. “It is becoming clear that the FAA is probably not going to certify the GPS constellation for FAA-certified flight safety operations … We have done some homework, and while we can’t meet the desired performance for autonomous navigation, we can do very well on two crosslinks.”
“Given the experience [the FAA] was having with the WAAS system, no one believes there is a practical way for the FAA to certify the GPS constellation,” he says. “It would probably make sense to have a two-tier solution. Have GPS be what it is, maintain WAAS for those that need it and not drive that cost into every one of those GPS satellites.”
For those readers who aren’t familiar, WAAS is the Wide Area Augmentation System. If you check the FAA’s website, it doesn’t mention that it’s a ground-based system that augments GPS. It’s got a pretty, little graphic that, if you’re paying attention, shows ground-based units, but given all their pie-in-the-sky proclamations [pun intended] about how NextGen is going to get rid of ground-based systems, I guess it’s understandable why they wouldn’t be more honest. Can’t have that, can we?
But, wait, those of us who have been around awhile know that WAAS was never intended to be precision-like, but LAAS (Local Area Augmentation System) was. It’s been renamed to GBAS, Ground Based Augmentation System.
Frye said, “we can’t meet the desired performance for autonomous navigation.” Yet one of the major selling points of NextGen is self-separation of aircraft. Lockheed Martin is concerned about “driving cost into every one of those GPS satellites”, which correlates directly into their profits and may ultimately adversely affect aviation safety if NextGen, as the FAA and JPDO currently envision it, gets implemented. Reread the article and you might pick up that they want to reduce the functionality to reduce costs…a recurring theme.
Sounds to me like Lockheed Martin is starting to bail supporting NextGen if it’s going to hurt their bottom line. That’s a problem when you contract out safety services…no guarantees that your contractors will renew the contract.