Is National Differential GPS Lost? 109
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."
Of Course! (Score:5, Funny)
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Differential GPS greatly improves your precision, from meters to centimeters, but you don't really need that to give directions. You'd want it if you were actually letting the thing steer your car, but we're not there yet.
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Welllllll...
Actually most consumer devices ALSO uses WAAS. Plain old satellite is "just fine" even without WAAS, but WAAS really helps refine the position.
Especially in the "urban canyons", normal GPS signals are pretty bad at times. Get in the city around tall buildings, and you'll see your accuracy get into the hundreds of feet if only three satellites are in view and lots of signal reflection
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Not true. In the middl of a cornfield in Knasas, where farm machinery is uften automated and steered via GPS, extreme precision is critical. Non only that, but your sample rate is often much higher than the .5 to 1 Hz seen in most consumer GPS units.
If your thresher (or whatever) is out in the fi
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By the way, do you know how the farmers still stay in business? I heard from a relative they only get about $10/acre at best. That just doesn't seem nearly enough to provide for the family, let alone buy GPS steering. Or do they also get the subsidies then?
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Doing a search on the Internet reveals crop guarantees at $167/acre when I did a search on Wheat. Now, I didn't very which year, etc. But I expect the document is 'current' (last five years or so).
$167/acre, with 1000 is $167,000 - costs = ?
While I don't know what farmers costs are, I saw numbers published a few years ago where the local farmers were complaining because they only made $45-55,000 Net Income.
I don't know about you, but where I live thats significantly above average net income.
You may not get
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So as long as everything goes smooth, a farm can keep the cash flow necessary to pay their loan payments, purchase their seed for the next season, and pay their salaries. But
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This is incorrect - DGPS improves the precision from somewhere around 15 metres to 3 - 5 metres - certainly nowhere near centimetres (which is pretty much impossible with GPS due to the wavelengths involved - I understand Gallileo will be providing a high precision service though).
But I'm unclear on why the loss of funding for DGPS is big news - is anyone still using DGPS? If so, why? If you've got a view of the equatorial horizon
You Know, This Kind of Is a Problem ... (Score:4, Interesting)
Now you're telling me that we can't afford to clip another $10 million off the Defense budget [wikipedia.org] and give it to this service (which may, arguably, help the coast guard in defending our shores)? Come on, we spend way more on military than any other country. It's good to maintain military superiority but do we really need it when you look at that chart? The next highest is China with maybe an 1/8th as much spending as we do. Give me a break!
There's no way anyone can justify cutting the spending on this program given what we've invested in it and how useful it is. When you look at where the rest of our spending goes, $10 million is nothing. No one can complain that the cost versus potential utility of this thing isn't high enough.
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Now you're telling me that we can't afford to clip another $10 million off the Defense budget and give it to this service (which may, arguably, help the coast guard in defending our shores)?
This kind of DGPS (type-1 or type-9 messages only) that the Coast Guard sends is of very limited utility. Now that "Selective Availability" (intentional noise added to the civilian GPS signals) is gone, there is very little positional improvement one gets from their DGPS. If they kill it, I doubt anyone but the folk
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SA wasn't a big deal to yachtmen as it was accurate enough. It was a much bigger deal for car navigation systems (think parallel roads 50 yards apart and chaos at junctions).
A few days after SA was turned off I went for a walk and the track
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They say that he's a VIP, (Score:2)
Honestly... (Score:2)
That was great man!
DGPS sites on internet (Score:3, Insightful)
Doom and gllom for punchcards! (Score:5, Informative)
I didn't mind punch cards being phased out either....
Re:Doom and gllom for punchcards! (Score:4, Informative)
LORAN is still up, you insensitive clod! (Score:2)
LORAN lives! (Well for a few more months anyway.)
http://www.gpsworld.com/gpsworld/article/articleD
And I think it is used more widely in the non-US, non-EU parts of the world.
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Really? Personally I couldn't care less about it - do you want to elaborate why you care?
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In theory yes, but you won't get the needed information from a normal GPS receiver. To calculate DGPS correction, you must calculate error for each satellite and feed that to other GPS receiver. If you just take difference between the right location and the location you got from NMEA output and use that to correct postition indicated by other, you will get greater error than without.
This is because each receiver picks a different set of satellites.
Budget Cuts (Score:4, Insightful)
Remember when GPS itself was thought to be in danger back in 2000 [pobonline.com]? Remember when there was talk of balancing the budget? Read this article [afa.org] all the way from 1996 about the military importance of GPS technology. It's worth the read.
About the NDGPS vs. WAAS debate: I work for a group that relies heavily on GPS for aviation purposes. As the number of uses for GPS expand, as they inevitably will, new technologies will spring up. NDGPS vs. WAAS is like 802.11g vs 802.11a. I think they both have a place. If the government won't support NDGPS, perhaps there is a commercial application? What are the FCC regulations on the 300KHz spectrum? If no one will pay for it, let it die, I think.
Okay, <rant>
I laughed when I read, "Therefore, when it comes to cutting the budget during tight times, programs like NDGPS are prime targets." How are we cutting costs when we just ran up a record high deficit in the last two years [zfacts.com]? I like it that we're cutting costs. Let's cut some of the really big ones, like military spending!
</rant> Couldn't resist.
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Except remember, GPS came from a black budget military spending project that made the military budget look bloated. Look before you bite the hand that feed, and make sure it's not going to slap you after you bite it.
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But, as someone else said, WAAS is much simpler to implement so I don't really have much of a problem with this - altough one could arguee that the two systems complement each other, which I'm not sure is the case, but
Um, why should it be saved? (Score:1, Insightful)
And this is a reason to spend a couple hundred million plus $10 mil/year in operating expenses?
I know it's not a large amount of money compared to the national budget, but it's still a lot of money.
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Check here [slashdot.org].
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The use of "GPS" and "WAAS" does make it clear. The FP did not say "GLONASS", or "EGNOS", or "GAGAN", or "MSAS", or even the generic term "SBAS".
The whole world can use GPS, but the US outright owns it and controls every aspect of its operation, whether the rest of the world likes it or not. Dubbya could order SA turned back on tomorrow, and all the foreign users that have come to critically require reasonably a
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Yes, and endanger every aircraft, cruise ship, and clueless-SUV-driving-mommy that uses GPS. And for proof, you need look no further than the occasional "test" that SA still works conducted every now and then. Have no doubt whatsoever that the moment a "terrorist" uses (or comes close to using) a GPS-enabled attack, SA will go back on.
GPS recievers have been able to correct for SA *before* it was turned off.
Key phrase missing - "over time". Yes, SA a
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And this is why the EU is constructing Gallileo (and also why the US has been so adamantly opposed to it).
if Bush decided to turn SA on tomorrow, he could also turn WAAS off.
And doing so would be proof that the US government is criminally insane - turning SA on and SBAS off at the same time would certainly endanger a lot more lives than most terrorist attacks. It would also be inte
Why don't they just publish the P(Y) keys? (Score:2)
Re:Why don't they just publish the P(Y) keys? (Score:4, Informative)
DGPS can be far more precise than military precise setting. A resolution of one meter is more than good enough for any weapon system that would use GPS.
I remember hearing about a form of DGPS that has a lot higher resolution than one meter. It is often used for surveying.
Re:Why don't they just publish the P(Y) keys? (Score:4, Informative)
That being said P code recievers make differential and carrier differential easier.
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This does depend on having sufficient satellites in view - this is a problem under trees and close to buildings and steep slopes.
Article Unclear (Score:5, Insightful)
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?
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Obviously it was written by a NDGPS hardware provider who is watching their future go awry. Won't anyone think of the corporations?!
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Both longitude and latitude (Score:2)
Look at it this way: whether you go up/down or right/left, you're still moving away from the point where the satellite is overhead.
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Not really - there are several SBAS satellites at different longitudes with overlapping footprints. If you can't see one then you are likely too far from the equator or so far out to east/west that you wouldn't get any useful DGPS data anyway.
WAAS & CORS = better? (Score:4, Interesting)
I much prefer using WAAS for real-time, especially after the two new satellites are up and fully functional. I do post-process most of my data, however, so the CORS stations work just fine for my needs.
LOST (Score:5, Funny)
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It's called progress (Score:2, Insightful)
Redundant programs being cut (Score:2, Interesting)
The FAA upset thousands of pilots when they pulled the plug on TIS (Traffic Information Service) when approach radars (ASR 9 to ASR11) were upgraded and their investment in TIS equipment was obviated -- the one they chose, ADS-B (Autom
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Rick.
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Poor guys... (Score:2)
Of course, nobody cares about poor blind robots, running around, bumping into walls. And what about blind human/robot hybrids? Are they stuck with their bionic seeing eye dogs?
GPS and ITS? (Score:2)
I understand the Positive Train Control part; you need to be able to tell where a train is in order to tell it what to do. I'm having a little more trouble with the Intelligent Transportation Systems part.
You don't necessarily need GPS to tell automobile drivers what's going on ahead of them; there are other, infrared or magnetic loop current-based ways to do that already.
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Beneficial for Robots? (Score:1, Flamebait)
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used by hundreds! (Score:5, Informative)
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.
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well, duh: Amtrak. helloooo! Anybody home, McFly??
employee tracking (Score:2)
The e-card provided information about the owner's current context and activities.
In other words, "managers could track employee's activities without having to look over their shoulders."
Ummm...could I skip this 'upgrade'?
Just do the job you're paid to do (Score:2)
There is no need for NDGPS. How WAAS works (Score:3, Informative)
Just to explain to the submitter if this is not already crystal clear: There is no need for NDGPS. WAAS has fortunaltely replaced it.
NDGPS required a seperate receiver to get the error signal from a ground based transmitter. You also had to be near a ground based error transmitter for this to work.
The ground based error transmitters are still there, and more are beeing added. Instead of transmitting locally, a database of errors over a wide area is constructed, and a geostationary sattelite transmits the error database on the same wavelenght as the other GPS sattelites to all GPS devices. All that is needed for this is typically a firmware update in the GPS unit.
Simple, effective, cheap.
Actually... I support WAAS (Score:3, Interesting)
WAAS is better (Score:2)
Go WAAS (Score:2)
for WAAS and it sounded disturbing. On a slightly closer
reading I see that WAAS is not in danger. It never was
and won't be. Hundreds if not Thousands of 'connected'
yacht owners would never find their moorings if WAAS was
shut down. Some of these are the source of government, er,
oil. I'm sure no one in government would want to loose
these users of WAAS.
NDGPS just better for some applications (Score:2, Informative)
1. Sky visibility can significantly degrade your accuracy via WAAS. Personally, working in a lot of areas with random overhead cover (trees) I prefer NDGPS to WAAS even if I have to download the corrections and post correct. In a test I ran in a suburban forested park NDGPS was able to meet the 1 Meter accuracy claims even with heavy overhead (40+ foot trees)in a comparison vs 6inch pixel aerial photography. WAAS consistantly got a ~2-5 meter error on the same locations.
2. NDGPS station
How about letting the GPS in my phone serve me? (Score:2)
Instead the phone company makes it impossible to do anything with it. In my case they don't even offer services for it.
somedays I'd like the technology to serve me; instead of big brother...
Business Issues (Score:2)
Of course, when you're talking sub-meter accuracy... well, here's hoping I have better employment by then since they're unwilling to listen...
Personal DGPS (Score:2)
How common are DGPS receivers?
Still would have CDGPS! (Score:1)
Reed
That's not trolling libertarians, THIS is... (Score:3, Interesting)
The problem, of course, is that the GPS broadcasts are a public good, so how do protect that, in order to charge for it? Encryption? If people get their hands on your device, they can break