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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."
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.
A community-oriented lyrics site
Would not actually be hard. Technically you could do it yourself. Really at it takes is a fixed location GPS (calibrated) hooked up to a server which processes the NMEA data and uploads the correction dynamically.
the more they over-think the plumbing the easier it is to stop up the pipe
As an outsider, I see two technologies that do more or less the same thing. One is better in every way. Its only downside that it's not usable in certain situations where the other might possibly be used.
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.
Please, when using terms like "national", make it clear which nation you're talking about.
The internet is GLOBAL!
Wouldn't the "Precise" code give better resolution than either DGPS or WAAS?
I didn't mind punch cards being phased out either....
Engineering is the art of compromise.
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?
I personally *hate* using the NDGPS (beacon) real-time corrections. We only have two reference stations in my state and neither are worth a damn in my city. I work as for a major GPS company, and though we do sell beacon receivers quite briskly, I hate using them.
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.
"Equal bytes for women!"
If NDGPS is indeed lost, can't we just use its GPS to find it?
The only thing I hate more than hypocrites are people who hate hypocrites.
WAAS is the next step in this technology. Let the dinosaur die and let's move on.
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)? 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.
My work here is dung.
DGPS does the correction on a satellite-by-satellite basis. The GPS receiver must support DGPS corrections, which are uploaded to the receiver to include in its internal calculations before the separate satellites are combined to form the final result.
Remember when GPS itself was thought to be in danger back in 2000? Remember when there was talk of balancing the budget? Read this article 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? I like it that we're cutting costs. Let's cut some of the really big ones, like military spending!
</rant> Couldn't resist.
Think about the implications if WAAS (and soon-to-arrive LAAS) is decommissioned -- the FAA has already issued WAAS-based LPV approach plates for IFR ops. Switching to another system would cause a huge momentum change in a critical sector of the safe operation of our airways.
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 (Automatic Dependent Surveillance - Broadcast) provides more data and is more scalable. Essentially instead of using radars and transponder return codes to figure out who's who, let the aircraft broadcast their position s constantly without having to wait for a radara sweep. But I digress.
Same with these conflicting solutions -- one my be "better" in terms of feature set but the other has momentum. MP3 vs OGG anyone? Beta vs VHS?
I'd rather have a standard augmented data-channel and ground based "satellites" to allow my portable GPS to function in the skyscraper canyons and provide local traffic and business lookups so that I don't need to subscribe to CD/DVD updates when the data could just be real-time.
Blind people and robots also benefit from highly accurate GPS navigational capability provided by NDGPS
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?
I lost my concept of community when my community lost all concept of me.
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.
-Rob
Biblical fiscal responsibility
A: A state of international affairs involving the risk of lots of hostile things flying really fast and accurately towards various precious destinations best hampered by withdrawing NDGPS?
Wont someone please think of the robots!
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.
I'm an American. I love this country and the freedoms that we used to have.
FTA:
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'?
Aah, change is good. -- Rafiki
Yeah, but it ain't easy. -- Simba
There is no need for NDGPS. How WAAS works
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.
"Fix it"
Oh, please. I think Libertarians are completely goofy, but this is just too easy. As long as you're a Libertarian who believes in initiation of force to protect intellectual property laws. Of which there are tons. Personally, I don't see how they wrap their heads around that without them exploding, but it works for them.
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 the encryption. It all boils down to giving a government enforced monopoly on using the broadcasts to the people who put the satellites up. Otherwise, the people putting up the satellites could never recoup their initial investments, as anyone could make a receiver and not have to pay the people putting them up.
But as I mentioned, plenty of Libertarians can quite easily wrap their heads around the paradox of enforced ownership of intellectual property. It all comes from a very flexible definition of "initiation of force." Basically, any use of force a libertarian doesn't like is "initiation of force," while anything else is "retaliatory force" which is, of course, justified as YOUR NATURAL RIGHT!
See, in order to troll successfully, you have to have an understanding, nay, even a love for that which you troll. You have to care enough about your subject to actually get inside and find out what makes 'em tick, what are their foibles, paradoxes and hot buttons.
So, any Libertarians out there want to respond to a self proclaimed troll and tell me how you would do it without intellectual property protections? I mean, if you thought protection of real property took a lot of state sponsored violence, imagine how much state sponsored violence is necessary for the protection of imaginary property? Come on, you guys are smart, I mean, it's not like you just memorize your party dogma and can't answer simple questions that fall outside the bounds of official, party sponsored reasoning, is it?
Happy Troll Tuesday!
P.S. As much as I think the vast majority of Libertarians are goofy, I've had conversations with some here who are probably smart enough to figure out how to do this, so even if no one responds, that doesn't mean all libertarians are dogma spouting mouth breathers who couldn't reason their way out of a paper bag. Some would manage to deduce that ripping open the bag was not in fact initiation of force, as the bag was depriving them of their natural right not to be in a paper bag.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
Because thats what my Garmin GPS uses. It (and I) have never heard of NDGPS so I hope WAAS doesn't get phased out. given that it also makes sennse to have a single standard, it makes sense to me for NDGPS to go away.
I was messing around on a friend's boat last May and turned on the LORAN receiver. Lo and behold it displayed a set of valid coordinates.
e tail.jsp?id=314650
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.
Give a man a fish and you have fed him for today. Teach a man to fish, and he'll say "WHERE'S MY FISH, YOU IDIOT?"
WAAS is better. All you need is one GPS reciever and it costs noting and is available everywhere GPS is. Differential was a great idea but they used a second back channel radio to broadcast the data. WAAS is almost the same thing but uses the GPS system itself to broadcast the data. Smarter really.
Won't somebody, anybody, think of the robots?
Before deciding that DGPS should go the way of the dodo, you should consider the international issues and penetration for DGPS and WAAS.
DGPS provides 1-3 meter accuracy with proper beacon reception equipment. The service delivers its coverage in circles around transmitter sites. The DGPS standard is an international standard, allowing precision approaches within 200-500 miles of a transmitter site. DGPS coverage is already quite good.
WAAS provides 1-3 meter accuracy with no additional equipment. WAAS itself provides this service in a service volume using two existing geostationary satellites.
Receiving WAAS service in the continental U.S. is sometimes difficult on the ground. Those of you who use GPS in mountainous terrain may have experience with this. Solving this reception issue inside the U.S. might be as simple as adding a third or even fourth satellite to transmit the corrections. Once receivers on the ground are better able to receive the correction signal, WAAS is clearly a more convenient solution.
NDGPS had a good footing and was a fantastic solution in its day. Discontinuing the sites within the U.S. is certainly a feasible budget solution. However in coastal regions, DGPS stations should be continued at least until the current generation of marine receivers is replaced.
At first glance I thought NDGPS was some synonymic acronym
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.
Three items of note:
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 stations are already failing in our area. Of the Three stations that are barely within the range at which they are useful, none consistantly provide base station data via the internet, and 1 has failed completely. If the current funding level is approved ($0) I don't see any improvement in the near future. Thus my company has invested in our own DGPS base station to guartee 1 meter accuracy in the event of NDGPS unavailability, despite the downsides (maintenance, requires a survey accurate point to permenantly mount the basestation, basestation must run at least one hour before and after field collection of data to insure coverage).
3. In our current contract with a US government agency that specified 1 meter accuracy GPS, WAAS was not an acceptable correction option. So it was either rely on unreliable Government funded base stations, or buy our own. (BTW, I'm glad we did buy our own).
My cell phone supports AGPS, while I don't know the specifics about the implementation (Motorola RAZR v3c) I wish I could take advantage of the fact it can do it.
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...
Cool maybe, but not particularly useful. Wireless internet access is expensive. Wireless one-way broadcast of RTCM is many orders of magnitude cheaper (both from a cost-to-consumer standpoint and from a cost-of supplier standpoint). And if you're not using a wireless connection, what's the point of DGPS?
Ya know, when I found this out I had to forward it onto our business group. Funny thing is, they had no CLUE it was happening.... and they aren't worried because the next product won't need it.
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...
and there's nothing to worry about.
Being northerly makes it harder to see a geosync satellite. What's less obvious is that being too far east or west creates the same problem.
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.
This could be, only in the USA.
The difference between 1m accuracy and 10m accuracy is being able to tell when "...train hundred-and-two / is on the wrong track / and headed for you!
To be completely honest... I laughed until I cried after reading your post.
That was great man!
Libertas in infinitum
... it pin-points the place and time where Congressional
and Executive Office Staff and Officials make cocaine
and prostitution deals on the streets of Washington
DC.
Oooopppp!!!!!
Having said that in a public place, I am ordered to have a
priviate execution by a seninor membor of the
US Executive Office [read GWB der Furer].
Ach Bin! Sig Heil! Toodles ze!
When the Galileo positioning system will be available by 2010 it will provide accuracy of 4 meters on the public service and better than 1 meter on the commercial service. Granted it some sort of enhanced GPS is needed in the interim but making investments in DGSP infrastructure at this time would be a waste of taxpayers money.
WAAS is emitted from geostationary birds. I'm sure the parent is aware that GPS is comprised of LEO's
I always wondered if an individual could setup their own DGPS and use it for navigating home robots. For example, my Roomba would be more efficient if it had a layout of my home and knew where it was. But GPS is too broad. But could I place a DGPS receiver in my house and make a GPS accurate to 10 cm (As I've heard people claim is possible)? If I understand the principle correctly, DGPS is just about knowing your position precisely and sending out correction information.
How common are DGPS receivers?
Well, there would still be Canada's national DGPS service, which covers most of the northern US (plus Alaska)! Plus the expensive commercial services if you really needed it.
Reed