Slashdot Mirror
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.
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
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.
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
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.
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]
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
Its not easy, but I can't see the infrastructure component of the system being more than a billion USD. That leaves you 39 GUSD to equip you entire aircraft fleet with mode S transponders. It sounds like an excessive price to me.
The big challenge for the ATC system becomes scalability. Current methods of detecting aircraft are:
The primary radars might have a maximum range of 100 NM. The secondary radars about 250 NM. ADS-C works anywhere you have satellite communication but in practice only airliners in remote airspace will be using it.
ADS-B gives you almost 100% coverage in your airspace. Many more aircraft are detected.
Putting an ADSB transponder in every aircraft in the sky (ultimately) means that the ATC system has to start dealing with many times more aircraft. At the very least you need better filtering to enable the controller to see the aircraft he has to control and not be distracted by uncontrolled aircraft nearby.
IMHO the torrent of new information will eventually lead to ATC systems delegating their tactical control to automated systems. Any other approach ignores the potential of this technology.
http://michaelsmith.id.au
Did you know the current system is based on the concept that everything in the system can fail at once and planes won't run into each other? Thats one of the reasons that towers still move little bits of paper around using a very well defined procedure.
You describe the secondary radar fairly accurately, except that all sites also use a primary radar in conjunction with the secondary. Primary radar is the "active" radar that everyone visions, and is exactly how ATC handles airplanes with no transponder. They will identify a "blip" by having the airplane make a specific turn, or series of turns, and then they can tag the target on the screen to track it.
Additionally, secondary radar is not entirely passive, it transmits an interragation signal, which the transponders respond to. Transponders do not volunteer information, they also do not have any anti-tampering provisions in them. Upon initial contact with ATC, ATC gives the pilot a descrete code to enter into the transponder, allowing the ATC system to tag it. If the incorrect code is entered, or the correct code is changed, the ATC computer tags it as an unknown flight, not some random other flight. The pilot would have to randomly fall upon some other descrete code that was in use by another aircraft to be tagged as a known flight. In that case, some confusion would result, but it would hardley be havoc. In any case, an airplane can still be tracked even with the wrong transponder code, or a malfunctioning transponder.