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Inside FAA's GPS-Based Air Traffic Control
longacre writes "With the growing number of planes in the air setting its archaic radar-based air traffic control on a course toward 'total system collapse,' the FAA has quietly begun testing a new GPS-based system on Alaska Airlines 737s. While radar can take over half a minute to determine a plane's location, GPS technology known as ADS-B broadcasts an aircraft's position to controllers and nearby pilots essentially in real time. If all goes as planned, travelers will see fewer delays as planes will be able to fly closer together and in reduced visibility conditions, and airlines will achieve significant fuel savings by flying more direct routes. The feds plan a gradual rollout over the next two decades that may cost up to $40 billion." There's still some contention about where the funding will come from.
to take 4 days off!
I can velcro a Garmin to the dash of every plane in the country, hook it up to a cellphone, and get the same data. And I'll only charge $39 billion.
Courtesy of Mr. John Q. Public, The Taxpayers. What? You thought the airlines would have to come up with the money to upgrade their equipment?
09F911029D74E35BD84156C5635688C0
+2 Troll is Slashdot's way of saying groupthink is confused
40 billion? Can anyone offer some financial perspective.. it sounds like that much money should completely replace all those airplanes!
LIke said above, using 3 sats. Calif altitude is identical to all others, x feet above sea level. Terrain avoidance is done by on board GPS units tied to maps, as well as radar altimeters. This is not so much about avoidance of terrain but avoidance of other aircraft.
"If the King's English was good enough for Jesus, it's good enough for me!" -- "Ma" Ferguson, Governor of Texas (circa
So we're talking $2 billion a year. Where to find it, where to find it . . .
Hey, I know! Let's cut U.S. farm subsidies to the levels farmers get in Australia and New Zealand. Surely American farmers aren't so incompetent that even with the advantage of cheap Mexican immigrant labor they can't compete on an even footing with Australians, right? So cut subsidies by 80%. That'll generate, oh, seventeen billion dollars. We can update the air control system in just three years, then, and then let the money saved reduce the deficit.
Mode-S a very nifty datalink system that uniquely identified aircraft and can beam all sorts of useful traffic and navigation information. It was designed *WAY BACK* in 1975, only to be ignored by the FAA (the airlines the FAA works for didn't want pay for it). So they ignored it until a mid-air collision in 1986 woke up Congress, who mandated it in 1993. ADS-B (the Popular Mechanics article seems to be describing) AFAIK uses Mode-S to broadcast your aircraft's position using Mode-S, but the FAA have started shutting down Mode S transmitters 'because the safety benefits are not worth the cost'. Nice idea, but I hope it doesn't take another costly "wake up call".
y .html http://www.aopa.org/whatsnew/air_traffic/tis.html http://www.aopa.org/whatsnew/newsitems/2005/051020 mode.html http://www.avionicswest.com/myviewpoint/modestrans ponder.htm
http://web.mit.edu/6.933/www/Fall2000/mode-s/toda
Lots of technogibberish here: Hey, Wiley! When are you writing "Air Traffic Control for Dummies"?
Technically, you'll need four or more satellites in view to calculate altitude. In general, you'll need (n+1) points of reference (satellites) to triangulate a point in an n-dimension space. (Assuming you want the position calculated in all n dimensions).
g ulation
In practice, three satellites are adequate for ground and altitude calculation (since most other spatial possibilities can be ruled out as being 'ridiculous').
For more info: http://www.beaglesoft.com/gpstechnology.htm#Trian
There's still some contention about where the funding will come from.
I hope there's also some contention about what will happen when those closer-together planes are left without GPS due to a war in the Gulf or some technical glitch, and the radar backup cannot keep up with the added traffic (if it could, what'd be the point?)
Rome taught me patience and assiduous application to detail. Virtues which temper the boldness of great, general views.
failures ?
A single plane that will have a broken device, and wont transmit its position properly will have the option of taking down a lot of stuff.
Whatever the shortcomings of the current radar system, radars tend to work regardless of the planes condition, and regardless of its position.
Heck, IIRC planes only need special equipment to identify themselves, not to tell if they are actually there, and where they are.
Sorry - but i prefer false positives (radar ghosts, or whatever their names) from false negatives (nah, its not a plane, it doesnt have GPS, it must me a bird. [15 minutes later] OH F*CK, EVERONE - RUN!!!....).
If its not going to replace radar systems for good - i see no point in spending 40b, and i dont see how it can replace them - given the requirements for such systems.
Which means that if there is a solar flare or something of the sort, the potential for disaster is enormous. Loads of planes flying around close together using a system that depends on vulnerable satellite links.
This is also assuming that air travel continues to expand. I know that /. is full of posts from global warming deniers, but now that even the politicians are starting to do things rather than talk, this could be a system that takes 20 years to implement and then is redundant.
Pining for the fjords
Doing away with paper based voting, radar positioning systems, and switching to bio-fuels is one heck of a tech addiction, but that's Americans for you. If you guys want high capacity aircraft to fly closer together and straighten flight paths to save fuel there is a way of doing it without the expense or danger. It's a called a frikkin train!
I'd estimate about 4000 planes from the 20 largest domestic carriers service over 90% of the flights within the continental US. as far as identification is concerned, look for a string of letters/numbers starting with an "N" painted on the fuselage, usually just in front of the tail.
i ry.asp
you can then use this page to look up basic info about the plane in question:
http://registry.faa.gov/aircraftinquiry/NNum_inqu
No you're not missing anything. The altimeter provides the altitude readout and it's just sent as a "sentence" along with the other information. Altitude data is already encoded from the altimeter and sent to the ground based radar as part of a coded signal from a transponder in the aircraft. This has been the way for decades. There is no need to get altitude from GPS. Position data from GPS is another thing. It is theoretically more accurate than a radar position, but there a bunch of innaccuracies that have to be built into a 'tolerance" that has to be applied to the aircraft position as reported.
TCAS is a traffic collision avoidance device also in use today that transmits altitude data between aircraft. Again the data comes from the altimeter.
Automatic Dependant Surveillance (ADS) data provides position (from INS or GPS) and altitude from the altimeter. The data can be sent via radio link or satellite. The amount of times per minute (or hour) that this data is updated to the ground station provides the basis for seperation of aircraft. If you update quite often you can run planes just a few miles apart. If you update every thirty minutes or so by expensive satellite links (trans-ocean) you might have to run the aircraft 100 miles apart. Some of the cost is in the aircraft but much of the cost is in ground station receivers, computers to interpret the data, displays to show the aircraft positions and then training for everybody along the line to use it.
The benefit is in better routing and less time in the "stack" when you arrive. Less fuel burnt is a cost saving but also think in total cost per minute of crewing and running a 747. It costs a bundle to switch to this but the longer term savings are far greater.
On the fuselage near the tail. There is an entire forum over at http://www.airliners.net/discussions/trip_reports/ filled with geeks that record these numbers in little log books for the purpose of wanting to fly every plane in the air.
They carry around cameras and binoculars viewing planes, taking pictures, and writing down little things on paper, all the while arousing suspicion amongst their cabin mates. Once they get bored with all that, they ask the stewardess if they can visit the cockpit. A fun hobby it sounds like.
That's what they own. They lease a bunch more, for a total of 600 planes. In terms of fleet size, they're behind American, Northwest and Southwest (and FedEx - those packages don't fly themselves, you know...). They're just ahead of United. If you regularly fly with one of the majors, it's not unlikely you'll meet the same planes repeatedly. Counting just major domestic carriers, you come out at ~3500 planes. But this excludes the foreign carriers you'll see at US airports (most of whom will be tending toward the 747/767/777 end of things and away from the CRJs), excludes freight and perhaps most importantly, excludes the code-share partners you see flying regional jets from small airports to major hubs. These latter are usually flying with the livery of the associated major, but don't have much more to do with them. They're external and just flying those routes under contract.
A plane's registration number is unique. You can generally see it somewhere around the rearmost door of the plane. You might find airliners.net interesting.
PenguiNet: the (shareware) Windows SSH client
Responding to some of the (typically) under-informed criticisms...
(Why bother to understand a topic when you can quickly post an opinion?)
This isnt intended to replace all traffic management, for instance at airports, just to lessen the overhead of overseeing the more predictable long stretches in-between.
Aircraft spacing would be lessened under the proposed system but still be considerable. Therefore even if GPS accuracy were degraded by the US Military it wouldnt have much practical effect. Besides accuracy to a few hundred feet is already problematic when youre traveling that far every second.
The new systems arent any more susceptible to interference from solar flares or other natural phenomena then current systems; indeed theyre predicted to be more robust.
Finally, 40 billion dollars US does seem like a lot of money. But considering the FAAs historic phenomenal mind-bogglingly beyond-grossly-incompetent record at managing system deployments its probably a low-ball on a cost-plus contract...
I don't read ACs: If a post isn't worth so much as a nom de plume to its author then I wont bother either.
And in the case the aviunics is failing, then the airplane will be invisible to everyone but radars!
The best way would be a (distributed) radar system + GPS.
You need both system failing in order to get an airplane lost.
Maybe Computers will never be as intelligent as Humans.
For sure they won't ever become so stupid. [VR-1988]
Let me fix that for you:
The altitude calculated by the GPS is way more imprecise than the value measured by the altimeter.
The FAA in technology terms are the dunce of the class in global Air Traffic Control terms, sure people can point to the "ooh its a big country" but Europe has a single upper airways control centre in Maastrict (Netherlands) and has continued to churn out new approaches and solutions from its single policy, R&D and Simulation organisation Eurocontrol. Europe is also embarking on a single pan-european system which will be deployed in around 15 years time (this is the HARD end of technology).
Part of the issue is the FAAs view that it knows best (despite the evidence to the contary) so when new approaches to ATC are created elsewhere (mainly Japan and Europe) they push back against them and try and create their own solution. They are continually trying to take the short cut (expensive short cut) with some new technology gizmo rather than doing the hard way of actually planning a pan-USA federated ATC system with a single upper airway controller and decent federation around the major hubs and then delivering that incrementally focusing on the key cruch points in the existing systems. They just look for the silver bullet.
The FAA is a case study on how not to do large scale IT, and a case study on how not to learn from others.
An Eye for an Eye will make the whole world blind - Gandhi
There's already a tested, approved and standardised system; follow links in this page for info.
But the inventor has for a long time been harassed by various US instances, in order to facilitate US interests, and that's why you won't see it in the USA.
Adventure, Romance, MAD SCIENCE!
There's still some contention about where the funding will come from.
Actually, there's absolutely no doubt where the money will come from - we the people. The contention is whose hands it will go thru first before the system is complete. The "who pays for it" question is a distraction in many, many public projects, such as "who pays for a cleaner environment?" "Who pays for (existing | preventing) illegal immigration?", etc.
In a way, it can be said that governments and companies have no money at all, except that which they receive from individuals. For example, car makers objected massively to adding airbags, and one excuse they pulled up was cost. But who pays for every part of the car when it's bought? Car makers? uh, no. Every added cost to everything is always passed on to the people who buy products and use services. It must be, or the companies providing products and services would eventually go out of business.
The "who pays for it" debate is always part of the push and shove of hogs eating out of the gov't trough. Sadly, most people don't get this at all.
Pavlov wouldn't be so famous if he'd used a can opener instead of a bell.
So.. instead of using radar to measure where aircraft are, you trust the aircraft to tell you where it is? Real reassuring.
Why can't we extend this system to cars? Scrap all the cops' speed measuring equipment and just wait for phone calls from speeding gps equipment wanting to fess up?
No, i didn't rtfa
They whose government reduces their essential liberties for temporary security, receive neither liberty nor security.
Yay for uninformed scare-mongering posts...
And satellites are far less reliable than radars.
Care to qualify that statement? Satellites are pretty reliable (I'd be inclined to say a single satellite is probably more reliable than radar, although I have no figures to back this up). Afterall, satellites are designed to run without maintenance whereas radars are not, so it makes sense that radars would be less reliable.
In addition, you would need to lose several satellites at the same time to render the GPS inoperable.
I don't want to trust my life on the optimistic hope that solar flars won't be at peak when I'm traveling
As mentioned above, you would need to lose several satellites at the same time to cause a problem.
Additionally, which is harder: disrupting radar systems, or shooting down a few satellites ?
Disrupting radar is probably a lot easier to do than shooting down several satellites.
which is harder: sending a few people to fix a broken radar in a few hours, or sending people up to fix a satellite in six months ?
NAVSTAR has been running for a long time without much trouble. There are more than enough satellites to cope with a few breaking at any one time and the satellites are fairly routinely replaced and deorbitted with no disruption to the service.
how many satellites would we need to cover reliably the whole planet before they can switch totally to GPS
24 satellites are required to cover the whole planet - there are currently 30 in operation.
http://blog.nexusuk.org
GPS Aided Geo Augmented Navigation aka GAGAN is what India calls it. This system is supposed to be operational in 2008.
wiki page
Details in google's cached copy of the announcement.
Google search would also get more details on this.
...the GPS, however, won't be in the bag when you get it back.
The FAA has been trying to upgrade the ATC for nearly two decades and is roughly seven years behind schedule from the original plan's timetable not the one they just changed to make themselves not look like total asses. The FAA has FAILED miserably and it is all of us who suffering. From longer ground delays at our nation's largest airports to few flights in smaller communities due to unnecessarily constricted airspace - the FAA's making it more difficult for all of us to fly.
I would suggest everyone read Michael Boyd of Boyd Aviation, an aviation consulting firm, that has been highly critical of the FAA and over a decade ago brought the idea of "Free Flight" to Congress but since that time has been ignored. Boyd has his pulse on the aviation world better then anyone I know and writes a column each Monday.
http://www.aviationplanning.com/asrc1.htm
Most planes have a dedicated instrument for just that purpose: the altimeter. IMHO GPS altitude is at best a backup.
For higher altitudes, the altimeter usually measures the air pressure. This isn't a problem-free method. You have to set the altimeter before each flight (to compensate for the height above sea level of the airport you're at). It's also not very accurate, as the indicated height varies with the barometric pressure. Incorrectly-set altimeters have been known to cause crashes.
A GPS altimeter would solve all this. Connect the GPS unit with a terrain map, and you're even better off: you'll know both your altitude above sea level, and above the local terrain.
before U.S. air traffic gets completely grounded? Nope, sorry, but I think I prefer the current system "warts and all."
This space intentionally left (almost) blank.
Actually, the engine was fine. It just no longer had a connection to the prop. Same result.
Oh, you can test the auto gear extension system in a Piper Arrow by leaving the cockpit vent window open on takeoff. Added another item to the pre-takeoff checklist after that one.
Without the 2nd Amendment, the others are just suggestions.
Has anyone considered the security repercussions of this idea?
If you trust the planes to tell you where they are, there is a potential that the planes could lie to you. I really hope they take that into account when designing the system.
Coding Blog
GPS has always had lousy altitude resolution compared to position over the ground. I've always thought it was both satellite geometry and earth model problems, but I can't really say for sure.
In any case, grandparent is currently correct: baro altitude is more precise than GPS.