Is National Differential GPS Lost?

Nealix writes, "This article at GPSWorld reports that National Differential GPS (NDGPS) is endangered in the 2007 budget. This has ramifications for a variety of government programs such as the Intelligent Transportation System and Positive Train Control by the Department of Transportation. Blind people and robots also benefit from highly accurate GPS navigational capability provided by NDGPS, which appears to work better in the urban canyons. If NDGPS loses, the winner would appear to be the FAA-backed Wide Area Augmentation Service (WAAS). Of course, what would be really cool is to see more GPS sites around the country make DGPS data (RTCM) available over the Internet."

Comments

Of Course!

[duerra]

Ah yes, of course GPS making use of DGPS data (RTCM) would be better than FAA-backed WAAS if NDGPS loses - everybody knows that. Now, BRB while I RTFA.

Doom and gllom for punchcards!

[EmbeddedJanitor]

Everything has its natural life, and WAAS is now a good replacement for beacon. So what if beacon differential goes away? WAAS is better: it is easier to add to a system (it uses L1 and typically needs no extra hardware vs beacon needs a special receiver etc), is cheaper, and is easier for customers to use.

I didn't mind punch cards being phased out either....

Article Unclear

[uab21]

Obviously I have missed something in TFA. It states that there are areas where NDGPD is available that WAAS is not, but that also WAAS is available where NDGPS is not. NDGPS requires additional hardware which is A) expensive, and B) bulky, whereas WAAS is available on pretty much all currently available receivers. Both systems (NDGPS and WAAS) have comparable accuracy (~1 meter).

Why, again, should we be sorry that NDGPS is going away? It sounds like market forces at work here. The only specific instance that TFA mentions where NDGPS has an advantage is *some* in-building penetration. Why should we build out a *national* network for only some in-building penetration? It sounds to me that WAAS is getting funding because it is technically and economically the better solution. Why is this a problem?

LOST

[EddieBurkett]

If NDGPS is indeed lost, can't we just use its GPS to find it?

used by hundreds!

[frovingslosh]

Right from the article: "used by hundreds if not thousands of users on a daily basis". This pretty much sums it up, there is an old technology that needs a special extra receiver that is used by hundreds of people (or maybe more) and costing millions of tax dollars, while there is now a widely deployed WAAS system that uses the same satellite receiver as GPS (no extra receiver required), is used by vastly more people, covers the country, and somehow the politicans have caught on that the old system is a waste. Although we may not be able to stop paying billions for bridges in Alaska that go to islands with 50 people and will admittedly help only realestate investors, at least they see the folly in supporting this old system. It should be shut down, in spite of any private agenda the original poster has.

On top of this, WAAS isn't the end of the line, there are more systems coming on-line that will improve GPS acuracy even more. The old system was OK for what it was, but the need for extra receivers by each user certainly limited it's adoption. It should be phased out.

And one thing I just have to comment on from the article and even the /. blurb: "Positive Train Control"! Are we really to believe we need taxpayer funded meter accuracy for GPS for train control? Do these trains really wander from from the tracks we know the location of? Isn't normal GPS accuracy just fine for choo-choo trains? And in the rare cases where higher accuracy might come in handy (although should hardly be needed), such as a switchyard, couldn't the location itself provide a small simple system for far less cost than asking the taxpayers to support it for this special use? You don't even need Internet data for this, you just have to agree on the location of the stationary differential receiver site and put a receiver without WASS there, it's error from it's known location is the same or better correction information than you could get from the Internet.