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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!
But does GPS show altitude? (or in the California, Altidude?) Because as they say, the hardest thing about flying is the ground.
And who should get credit for this amazing change in policy?
It never occurred to me to wonder how many planes there are. It seems amazing to me that a major carrier can serve the entire US with just 369 planes. Does that mean that all air travel in the US is served with just a couple thousand planes?
Where on the plane is a unique ID that I can write down? I'm curious how often I've flown on the same plane.
Cow Cube
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"?
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!
40 Billion buys a lot of new Phased Array Radar systems... If the FAA want to rely on aircraft based GPS i'm catching the train...
http://www.wimo.de/sbs-1-virtuelles-radar_d.html (which originally belongs in a Frame) is the site of a German radio enthusiasts' shop offering a hobbyist receiver for such a system here in Europe. So what, precisely, is new about that system?
With respect, you seem to be under the false impression that US Farm subsidies actually go to American farmers in the first place. I'm not an expert (and stand to be corrected), but after a few minutes of anecdotal looking around, it seems to me that they don't. eg. [1] [2]
So in other words, American farmers probably could shoulder a massive cut in American farm subsidies. Ironically, they might even benefit from it.
Radar is one part of the air traffic control system. It is especially important in 'controlled airspace'. Controlled airspace usually surrounds airports that have air traffic controllers. Most of the space between airports isn't controlled and most of the aircraft flying between airports can spend large amounts of time outside radar coverage. Within the controlled airspace around airports, the limiting factor doesn't seem to be the radar so much as the ability of the air traffic controllers (people)to keep track of the planes in their sector.
The route that an aircraft flies is determined by the plane's ability to navigate. There is nothing to keep a pilot from filing any random flight plan outside controlled airspace. The trouble is that most airways are straight lines between ground based navigational aids ie. VOR/DME, TACAN and NDB. A flight plan would consist of a series of bearings to and from the various aids along the route. If the plane has a computer based navigation system, any random route (ie. a straight line between two cities) can be chosen and the computer will take inputs from the nav receivers and calculate any path that doesn't have to follow the established air routes.
The GPS system has been on the books for years. In fact, for the last thirty years we have had a schedule of when the traditional aids to navigation will be removed from service. The good thing is that GPS is a lot cheaper than the traditional aids because it isn't necessary to maintain the ground based equipment. The expensive electronics go in the plane (paid for by the owner of the plane) and not on the ground. At this point the most expensive part of the traditional system (because it is already paid for) is the maintenance infrastructure. GPS will make it possible to lay off a bunch of electronics techs. The downside is complete reliance on one system. That's bad. If, for some reason, the GPS quits working everyone is in big trouble. The traditional system has quite a bit of redundancy because even if one aid goes down, there are many others. It would be very difficult to kill the whole system. GPS seems vulnerable to hacking by foreign governments in time of war. It seems reasonable to think that the next time 911 happens, the GPS system might be turned off and all the planes in the air would be flying blind.
We have had the technology to fly planes close together for many years. Consider, for instance, the Berlin airlift at the end of WW2. http://en.wikipedia.org/wiki/Berlin_Blockade
Anyway, the GPS thing has been on the books for a long time and saying that the existing 'radar based' nav system is close to the breaking point is just PR.
No way I'm going to board a plane that only relies on GPS. GPS does only work if the satellites work, you know. And satellites are far less reliable than radars. I don't want to trust my life on the optimistic hope that solar flars won't be at peak when I'm traveling, or that thw GPS will update itself for 20 seconds just when we're approaching an airport in fog at night you know. Additionally, which is harder: disrupting radar systems, or shooting down a few satellites ? Oh, one more: 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 ? Oh, wait, wait, there's more: how many satellites would we need to cover reliably the whole planet before they can switch totally to GPS, while the radar-based system just works ? Ok, I'll leave the rest to you fellas.
I am putting myself to the fullest possible use, which is all I can think that any conscious entity can ever hope to do.
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.
I'd like to put a GPS in my bag and see why the airport wizards can't get my luggage from point A to point B on a non-stop flight. Solve that mystery and maybe there could be some merit to this new system.
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]
Wouldn't this make it possible for an attacker to lock-on to the GPS location transmission and launch a fire-and-forget SAM? A truck full of rockets could be remotely controlled to takeout every plane in its local airspace with very little effort. The security of any data transmissions for civilian use cannot be that good because the information is made available to other planes and ATCs in the locale.
I would have thought that tracking regular GPS transmission significantly simplifies steering rules for a rocket compared with IR/Active Radar/Radio triangulation tracking. The GPS information provides ground speed as well as position so it is possible to extrapolate the position between transmissions, it should be sufficient to get the device within a few hundred feet, after which terminal guidance can be achieved using heat-seeking.
(IANAAE - I Am Not An Avionics Engineer).
Read http://en.wikipedia.org/wiki/AeroPeru_Flight_603 to see how a blocked pitot-static port caused the crash of Airoperu 603 and how the air traffic controller had no idea of the true altitude of the plane because the altitude that was being shown on air traffic control radar screen was being broadcast from the aircrafts transponder which was incorrect due to the blocked pitot-static port.
These will have significant problems due to the lack of on-board power for the transponders. Many don't even have space for the batteries!
But presumably they aren't of interest to the politicians.
Meanwhile, in the UK and elsewhere, Mode-S transponders will soon be mandatory.
I wonder why the Australians (who first tried ADS) decided last year to implement primary and Mode-S radar all across their country...
- australian-radar-contract-mode-s-radar-implementat ion-for-australia/
http://www.skycontrol.net/industry/thales-awarded
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
Over the past 30 years the FAA has consistently demonstrated that it is not capable of deploying a single pan-USA system to improve air-traffic control in the United States. They've wasted tens of billions of dollars in badly thought out schemes to replace the current system and have consistently not learnt from the lessons of other major ATC areas such as Asia and most especially Europe.
Why on earth would anyone think that the FAA, who have delivered bugger all in 30 years, will be able to deliver now? Its time to take a new view on what Air Traffic Control in the US should look like and take delivery of the next ATC system out of the hands of the FAA.
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!
I happened to write software in about 1990 for one of the early GPS Navigation systems for boats. Cost about $4000 :-). During Gulf War I, the British forces were a bit short on GPS units, so they improvised, these units worked quite happily in aircraft like Tornados and also for land units i.e. well outside the velocities they expected to be travelling at. :-). I quite happily trusted this unit (hooked up to an autopilot) to drive me around the coast at 40kts, only inputting waypoints and checking that we reached the right destination. And we didn't have 100% coverage then :-)
Oh, one more: 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 ?
Umm, GPS is composed of 30 satellites in operation currently. From what I vaguely remember, you need between 18 and 21 for full coverage. A number of spares are already in orbit, and on top of that the European based Gallileo system is expected to be broadly compatible when/if it gets going. Also the Russion GLONASS system may be migrating its standards to be GPS compatible.
Additionally, which is harder: disrupting radar systems, or shooting down a few satellites ?
Radar has multiple single points of failure. It would be easier for teh mythical terrorists to kill a radar dish than to shoot down a satellite.
Its quite cheap to put 2/3 GPS units in a plane to cross check each other. In addition you can have multiple differential GPS transmitters for a low cost.
don't want to trust my life on the optimistic hope that solar flars won't be at peak when I'm traveling, or that thw GPS will update itself for 20 seconds just when we're approaching an airport in fog at night you know
GPS navigation units normally also have inputs to take readins from backup navigational equipment in the vent of failure. Even on boats, it'll accept inputs from boat autopilots/ dead reckoning systems and use that info if all else fails. GPS units normally update position several times a second too.
Donte Alistair Anderson Roberts - hi son!
Karma: Chameleon
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.
I didn't see it in the article but are there any checks on the data supplied by the transponders ? Could you feed in false GPS data and make your aircraft disappear from where it is and put it somewhere else ? Is there crypto in this system or is everything just trusted ?
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.
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.
Here is the correct URL: Håkan Lans
...the GPS, however, won't be in the bag when you get it back.
is that it doesn't work in tunnels ;)
Holy shit.
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
What the hell?
Am I the only one who thinks this is an outrageous amount of time to test a GPS system and install it in a bunch of planes? I know the FAA is slow at doing things, but this seems excessive.
Given the venom of your post, I suspect that I'm not the one with religion here. You don't claim to know anything about the air navigation system and I believe you.
I also suspect that you missed my point: Saying that the current 'radar based' air nav system is close to the breaking point is just PR. GPS won't fix the problems in the system ie. congestion around major airports and the inability of human air traffic controllers to keep track of what is going on. In fact, if they fly the planes closer together, the problem will get worse. Citing the current 'problems' of the system is only trying to justify a decision that was made more than thirty years ago.
If you're curious, here's a link to the wiki article on air nav. http://en.wikipedia.org/wiki/Air_navigation
"...radar can take over half a minute to determine a plane's location."
This is semi-fact whittled down into a nice, scary summarizing sentence of sensationalist bullshit. I fly in the National Airspace System regularly. Unless the controller is busy talking to other aircraft, it never takes more than 5 seconds for me to hear "Radar contact, 3 miles east of (insert departure airport here)."
Of course, they could be talking about the time from takeoff until an aircraft reaches an altitude where local terrain allows line-of-sight between the aircraft and the ground-based radar antenna.
The current radar system is generally passive. That is, each aircraft allowed into class A or B airspace (above FL 180 or near one of the major airports, respectively) has to have a transponder. This transponder transmits a repsonse to the radar's ping. The range of the aircraft is determined based on the round trip time of that request / response. The altitude is reported by the aircraft itself, via an encoding altimeter. With GPS, you can get altitude (in the cockpit, and then presumably off aircraft with a new GPS transponder system in the future), but it is generally not as accurate as pressure altitude from an altimeter. With WAAS, however, it is extremely accurate. Basically, you are adding an extra "GPS," but at the airport, that gives you a differential signal on top of the satellites which allows even more accurate altitude calculations. I don't know the exact numbers, but it is enough to do ILS-type precision approaches. And while I love GPS, I'm also a little skeptical that it is going to solve congestion issues. Most people here probably are not aware, but something like 80-85% of *all* airline traffic goes through the major 25 airports in the country. Yet there are 10,000 airports in the US. The issue is not airspace - it is airspace and runway space around these major airports. Switching to a GPS navigation system will not get you more runways, better configured, at O'Hare airport. Nor will it take away fog in the Bay Area which prevents simultaneous ILS approaches from being run. I do think it will help, but it's not a panacea. Frankly, I think it's more useful for getting rid of costs associated with maintaining old VOR and NDB stations. I'd be interested to know how much the FAA spends on ground based VORs, as well, as there are hundreds of those in the US. They have to be secured and maintained. I suspect that $40 billion may be a bargain once all those VORs can go away. That's just a guess though. As far as comments regarding time and cost to upgrade - yes, that's a long time, but who gets to decide to force every airplane owner to buy $10k (for GA, probably much more for a commercial system) worth of equipment just so he can do what he did in the airspace the day before? Keep in mind, too, that a lot of the demands of the current system are created by the airlines, not GA, so it is not unfair that GA should have to upgrade immediately. Until last year, I was flying a plane that was close to 50 years old, so airplanes have a long life, and it's not just a matter of mandating new aircraft have the equipment, therefore the problem is solved in 5 years.
Current radar sends out a radio signal that reflects off an aircraft. That raw return or reflection to the radar antenna is interpolated and displayed on the controllers screen. In the case of national security, controllers are monitoring the radar 24-7, for suspicious radar tracks. ADS-b requires that each aircraft have equipment that receives a signal from the the ground radio, adds its unique id(to identify itself) and other info like altitude. Many things can go wrong. The aircraft must have the equipment. It must be working. It must be on. It must be calibrated. The altimeter in the aircraft must be set. What about international flights, will we require them to equip? In this case of national security, a pilot would only have to turn off or disable the ADS-b to evade detection. You also have to question the FAA's costs for this system. Is it just for their piece of the puzzle or will they pay for the equipment in each and every aircraft? That $40B could easily double. ADS-b does have value however. In portions of the country like Alaska were terrain blocks radar coverage, ADS-b is proven to provide aircraft and controllers with the information they need for safety.
I am sure that this is great technology, but it will only encourage the airlines to continue to switch from large aircraft to so-called regional jets. Since the total number of people flying is either stable or increasing, the net result is that there are more smaller aircraft in the air today that ever before. That's what's causing the delays.
Salon recently published a good description of the problem, written by an airline pilot.
someone please save us from the airline industry. it has turned into a giant pain in the ass that pretty much no one enjoys using. its pretty sad when a 1 hour flight takes over 4 hours from entering the airport to getting your luggage at your destination. security is the biggest joke, if anyone actually thinks we are safe you are deluding yourself, all of the checks are a waste of time and money, if hijackers really wanted to take down a whole fleet of planes they could on a whim. people need to stop living in fear and letting it rule their lives.
so what can replace the airline industry, i don't know, but i want it now more than ever.
What some posters fail to realise is that planes can be flown safely even when something like ADS fails or is not available. This sometimes occurs when ATC systems or communications networks fail, which like all man made engineering systems can and does happen. Controllers manually control the flights and increase their separation. They are trained to do this and the systems do support them.
I'm trying to find out when GPS was first introduced in the skies, but some posters seem to think this is a new technology and will bring disaster when the Gulf War escalates or a sun flare occurs. I'm pretty sure GPS has been used in the skies for quite some time and I don't remember hearing of any disasters during wars or sun flares.
If ADS does fail, position reports can still be sent by the pilot via voice communications.
The discussion so far makes it sound like GPS is the only way to navigate. Modern airliners navigate just fine, to any point in the airspace, based on the existing ground-based navaids (scanning DME is the prevalent method). GPS does, with augmentation systems (WAAS, LAAS) enable precision approaches to any airport, which is a real capacity benefit.
There is also confusion about the difference between navigation and surveillance (telling the ground systems where the airplanes are). This need not be connected directly to navigation. As mentioned above, Mode-S, or other methods of Automatic Dependent Surveillance - Broadcast (ADS-B) would accomplish this. In Alaska, there's a lot of non-radar airspace, so ADS-B is being used to fill the gaps. ADS-B can also enable new procedures, including tighter separation standards, that would improve airspace and airport capacity. GPS is not required, however, to have effective ADS-B.
The biggest potential benefit of GPS and ADS-B is that you could decommission those ground navaids and radars and save lots o' money. But no one has come up with a plan that has the appropriate fail-safe characteristics (GPS jamming?) and would satisfy the DoD (if you aren't reporting your position, only radar can find you).
The article, by the way, is full of crap. Of the NextGen technologies, GPS is one small element. ADS-B is much more important. But most important, we need more runways and airports. It's a simple fact: if people are unwilling to let airports expand, they are going to be flying at 4AM, or be willing to put up with lots of delays.
Improved en-route traffic control is a fine idea, and should help save fuel and shorten flight times, but I seriously doubt if it will have a significant impact on delays.
Over at Salon (ad-view required for non-registered users), Patrick Smith has had a convincing couple of articles making the case that delays are a side-effect of airlines using more smaller airplanes to move passengers around with more flexibility. More operations (take-offs and landings) with fewer passengers per operation means airports operate near or at capacity, which makes the whole system react to what might otherwise be localized disruptions, like weather delays or mechanical problems.
The other driver is economics -- airlines aren't stupid, they've noticed that even if they make passengers uncomfortable, lock them in airplanes in the tarmac for hours, never tell them what's going on, and take away their snacks and pillows, the passengers will nevertheless keep coming back. The only thing that makes them go away is raising fares. As long as this is true, service will get worse, and fares will go down.
2*3*3*3*3*11*251
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.
This whole article is FAA propaganda.
1. In the example they use, a 400 foot overcast is plenty above minimums for a cat 1 ILS approach. Most modern airliners flying into the large airports use cat 3 ILS, which is much more accurate. GPS approaches at the airports operated by air carriers would be redundant and provide less accuracy. GPS approaches at small general aviation airports, on the other hand, would be a welcome improvement.
2. In a recent Dept of Transportation study, it was concluded that 80% of all air traffic delays is due to other weather (e.g. thunderstorms that they have to deviate around and snowstorms that require planes to queue for deicing and clearing of runways -- stuff not going to be fixed by GPS and ADS-B) and the airlines' stupid hub and spoke architecture (which causes delays by ground congestion at the largest airports).
3. The jet routes are currently pretty optimal. The most you could gain by going direct instead of flying a jet route is about 5%. The savings are going to be so minute, it's ridiculous.
The real reason? GPS is cheap compared to maintaining the existing expensive ILS and VOR ground-based navigation system. The FAA wants to switch to a more modern system to save costs over the long run. Nothing wrong with that, but you get higher priority by scaring people into thinking the current system isn't safe.
It doesn't seem likely that we can protect our orbiting assets too far into the future. At least with ground-based systems we might have some countermeasures in place. Won't satellites be sitting ducks for the foreseeable future? If air traffic controllers spend years becoming acclimated to a GPS system, how quickly (if at all) will they be able to switch to a backup system?
You, the Taxpayer, will one, pay for the government side upgrades with your taxes. Two, will pay for the higher ticket prices for the airline side. The government will seek proposals from the usual suspects, Lockheed Martin, Boeing, IBM Consulting, SAIC, Northrup-Grumman, and maybe Raytheon, with a host of sub-contractors.
Could someone explain why the pilot is even necessary anymore? Just pay a sky jockey to sit and babysit a computer and let that fly the aircraft. Hell, we do it with prostate surgery now, why not a jet aircraft.
The only caveat is that the system for flying the aircraft not use Windows in any way, shape or form.
THE reason they still move little bits of paper around is because its a job staffed by a trained Air Traffic Controller pulling down a nice salary for moving around those bits of paper instead of letting the computer put the information on a display.
Well considering the obvious applications of the upgrades its actually a deal, we could use these newly upgraded plans to fly troops out of iraq netting 360bil in the first year alone... its a lack of GPS driven planes thats keeping them there, right? I certainly can't think of any _other_ logical reasons...
I mean, I don't even get fricken peanuts any more. They must be saving up for this! That, and they've shrunk down the pillows. Gotta be savings there...
There exists no way of exchanging information without making judgments. --Bene Gesserit Axiom
If all the NIMBYs were banned from flying, their minds would change after a year or two and more runways would be built.
One runway can only support 60 landings per hour, period. JFK, Newark, and Laguardia have 5 landing runways at any given time (the rest used for takeoff or taxiing). So DFW has a total of 7 runways, with 4 landing runways. So the problem isn't airspace, the controllers are putting them in as fast as they can, but when you have a limited number of runways, there forms a line, and the line leads to delays.
Get the best GPS position and all the technology, but you will be only a ½ mile closer in the long line to land on the runway.
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
Everyone here seems to focus on the commercial airlines and the ~4000 (give or take a few) airplanes. What people are missing are all of the business / corp jets that fill the sky and use the same system as the commercial airlines do. They don't share the same chunk of the fees that will pay for this system that everyone does (note: all the fees attached to a typical ticket). They typically land at smaller airports that don't charge the same large fees, but they do use the same air traffic control system that the commercial airlines use. I don't know how many of these planes there are, but a safe guess would place it at greater than or equal to the number of planes in use by the large airlines.
Now, there's no money in Brazil to fund "real" air-traffic control. Is anyone expecting a new expensive GPS based system to "fly" there? I don't think so.
BTW, Air traffic control in Brazil is currently considered unsafe(PDF).
I'm currently tasked with buying primary and mode-S radars in Europe. So, let's add some points to the discussion. - ADS-B is not Mode-S. For ads-B, you use the mode-S transponder on board of the aircraft to transmit the signals. Having a mode-S transponder with the broadcast capability is however not sufficient. You also need to connect the avionics to the mode-S transponder. This is not a simple task in older aircraft. - Tests have shown that many ads-B transponders (at least in Europe) transmit incorrect or inaccurate information. (you might find the correct numbers on the airborne monitoring program website of Eurocontrol). - Many readers present a list of surveillance systems (radar, Mode-S radar, ads-B) They however forget a very important one: multilateration. MLAT uses triangulation on signals transmitted by aircraft. The ADS-B signals are excellent for multilateration. However, MLAT determines the position of aircraft independently from the message content. So, if you place an incorrect GPS position into an ADS-B message, MLAT will not be tricked and still report the correct position. MLAT is used at many airports for local systems and is also deployed for larger areas all over the world. The disadvantage is that you need four times as many receivers as for ADS-B only. - There are a lot of mechanisms to minimize the number of faulty transponders. In Australia for instance, the quality of the transponder is checked while the aircraft is flying in an area with radar coverage. If the quality is ok, it is allowed to fly ADS-B only routes. - There is indeed a threat of people disabling on purpose the transponder. However, this is an attack on your country, so a military issue (they have primary radar) Furthermore, currently the controllers cannot see any aircraft, so it is currently also possible for someone to remain invisible. - Failure of GPS is possible. However, in ADS-B only environments, separation between aircraft will probably remain larger than in areas with multiple radar coverage. This means that in case of global GPS failure (or more likely, failure of the FAA equipment), controllers switch back to the type of control (and separation) they now apply. Controllers are trained in these procedures.
There is MORE than a little contention on the costs. The FAA is asking for a 400% increase in the tax on aviation fuel and The FAA is asking to charge ME a fee everytime I call them on the radio and tell them where -I- am. That last part also known as 'user fees' is disasterously dangerous, and could get a few people killed and alot of people scared as pilots stop calling in when they are flying in the lower and unregulated spaces around buildings in big cities. Also, the new system should cost so much less to install and run, that the savings on NOT using the old system could more than pay for the new system. But the FAA is trying to scare congress into a lot of new taxes.
It works like this: Every federal acquisition contract has to go through a competitive bidding process. The outcome of each will result in winner(s) and even more losers. The losers immediately take the result to court, or to their local congresspersons. The modernization programs are halted, pending court and/or congressional proceedings. The project eventually dies as funds are expended defending the original decision making processes and contract awards.
I know a guy who works for Boeing on such contracts. Their legal staffs are often much larger than their engineering staffs just to handle the contingency of losing a contract. I'm sure its pretty much the same for every other supplier.
Have gnu, will travel.
An interesting application of ADS-B is the ACSS SafeRoute program, currently used by UPS in their Class 3 Flight Bag based CDTI (Cockpit Display of Traffic Information) application (produced by Astronautics Corp of America).
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It allows for efficient merging and spacing of incoming aircraft to reduce airtime- and subsequently costs.
A summary of the technology and the players: http://www.aviationtoday.com/av/categories/commer
Certification flight on June 19th, 2007: http://www.aviationtoday.com/categories/bga/13101
First - altimeters measure air pressure at ALL altitudes, that's their function in life. The altitude they display is just a mechanical relationship between the outside static air pressure and an internal reference, calibrated to account for changes in barometric pressure. The only difference is that above 18,000 feet MSL (above sea level), aircraft all set their altimeters to the same reference (29.92inHg) regardless of location, and ATC handles separation by radar.
Second, the altimeter gets set before flight, this is true. It also gets continually checked and reset in flight as you pass weather reporting stations or when ATC reports a pressure reading to you; when I do a local flight even less than an hour I will probably check and reset mine a half dozen times. This is how aircraft keep themselves accurate in terms of relationship to the ground and each other. Regarding accuracy, before a pilot leaves the ground they cross check the reading on their altimeter to the elevation of the runway they are departing from; you can adjust slightly if necessary, however if a large discrepancy exists then the airplane is legally not airworthy, as all instrumentation must show accurately prior to flight.
Lastly - while a wrongly-set altimeter can induce the pilot into CFIT (Controlled Flight Into Terrain), the altimeter is reading wrong because of complacency (either set wrong, or broken and not noticed); complacent attitude is arguably the #1 killer of pilots and their passengers no matter what got them into that situation. GPS is a great tool in the cockpit, but it isn't the panacea some people seem to think it is. It can provide a wealth of information and help facilitate better decision making, but if the interpreter of that information (i.e. the pilot) treats it wrong or doesn't pay attention, no GPS will save them. I have even read many accounts of the enhanced information letting pilots believe they suddenly could fly into worse conditions than before simply because of the glowing screen in front of their face, and many airplanes (and lives) have been ended as a result.
A pilot's attitude and knowledge (through training and experience) are far greater tools than technology. Technology only complements those assets when they exist already, it does not replace them. A good pilot will recognize the difference. I embrace technology in the cockpit, but over-reliance on it (particularly when it's based on a misunderstanding of the systems already in place) is a fatal mistake.
I guess the FAA has completely disregarded the APRS (Automatic Position Reporting System) by Bob Bruninga, WB4APR, which has been developed by amateur radio operators for EOC and Search and Rescue Operations. There has been a system in place for the military as well for decades.
Actually, GPS altitude data is in reality not so hot.
The triangulation calc that's carried out to work out positions doesn't extend well to produce altitude info, due to the likely positions of the satellites. To use GPS terminology, VDOP >> HDOP. Then you have the fact that GPS altitudes are actually altitudes relative to a datum Geoid, rather than the actual Sea Level height... so they themselves are an approximation.
For barometric altitudes, the big problem is the drift in the underlying barometric pressure due to weather systems as a plane flies along it's flightplan, but these are generally cancelled out by resetting the altimeter regularly to relayed ground readings when moving from one flight information region to another.
Barometric altitudes are generally more accurate by perhaps a factor of 10 than GPS altitudes (error of 30ft vs 300ft) but the drift in barometric readings due to underlying pressure changes is in itself a problem which if uncorrected can easily result in errors as large as 1000ft (30ft per mb).
So both systems have their own difficulties.
Regards,
Mike
Think today's great? Should've been here *yesterday*.
You have a very good point. GPS is very easy to jam. By the time the signals reach the GPS locator, they're very weak. A moderately powered jammer close to the receiver would blot them out. You *NEED* redundancy in such a critical system: GPS *AND* ground radar.
The FAA (US) and CASA (Aust) Motto is supected to be "were not happy until your not happy!
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