Catch up on stories from the past week (and beyond) at the Slashdot story archive

 


Forgot your password?
Close
typodupeerror
×
Technology

Guiding Air Traffic Sans Radar With GPS 197

Posted by timothy from the please-use-a-backup-system-ok? dept.
CamMac writes: "UPS Aviation Technologies, a subsidiary of UPS, helped in developing a new air traffic control system called ADS-B in which the aircraft broadcast their position, altitude, and airspeed to each other and the ground based on GPS data. This is all done without radar, so it is effective in remote areas or in mountainous terrain. It also displays all this information to pilots as well as ground control, so that aircraft are no longer dependant upon crypic orders from the gound to understand where everyone else in the sky is." Besides being a smart way to take advantage of all those GPS satellites, this also lends plotline cues for remakes of such classic cinema as Goldeneye, Diehard II and Airplane.
This discussion has been archived. No new comments can be posted.

Guiding Air Traffic Sans Radar With GPS More

Guiding Air Traffic Sans Radar With GPS

Comments Filter:
  • Hey,

    this also lends plotline cues for remakes of such classic cinema as Goldeneye, Diehard II and Airplane.

    Ah yes, but when I map all the planes in my locale onto my car's GPS system, it'll make 405 the movie [405themovie.com] and That Scene(TM) at the start of Terminal Verlocity [deseretnews.com] even less believable. (Note: If you havn't seen 405 the movie [405themovie.com] yet, follow that link!)

    Michael

    ...another comment from Michael Tandy.

  • Re:Removing Dither.. (Score:2)

    by Anonymous Coward
    You're confusing two separate issues: SA and encryption.

    SA (selective availability) is an intentional dither introduced into the commercial, non-encrypted GPS signal. SA has now been discontinued, allowing commercial receivers to provide much more accurate results.

    The GPS broadcast also includes a military sub-band, which is encrypted. The military portion of the GPS stream provides greater accuracy (for both position and time). Encryption has not been discontinued, for exactly the reason you point out (subversion), as well as to avoid providing military-level accuracy to our foes.

  • So, what's to stop me setting up my own transmitter to overload a given area (say, the 70,000 square miles around my house) with a million fake planes?

    Or what if I know the id code of a plane before it gets to me, and I start broadcasting that I'm that plane? What happens when it arrives?

    -
  • I thought that GPS could not be used by airplanes...

    That is, a (civilian) GPS would not work at a speed above 200 miles per hour, reportedly to prevent terrorists from using it to guide smart bombs to their targets.

  • What if someone jams GPS freqs in an area?
    A couple of years ago, someone at the Rome AFB in central NY accidently jammed GPS in that region for days. To quote the article,
    An errant Air Force transmitter in upstate New York jammed Global Positioning System satellite navigation signals for two weeks earlier this year, with at least one Continental Airlines flight reporting a total loss of GPS signals and a dozen other GPS-equipped aircraft filing interference reports, according to officials from the Federal Aviation Administration and the Defense and Transportation departments.

    You can read the entire article [208.201.97.5] for more details.
  • We need better technology for ATC; this summer's rash of delays and near misses has shown the strains of the current system nearing its breaking point. Giving the pilots and traffic controllers better information is always a plus. Also, this system (if properly designed) should only enhance the current centralized system with its additional decentralized data points. However, it should definitely undergo rigorous and thorough testing before being widely deployed and relied upon for passenger safety. The ideal system would have radar, GPS, weather and map data integrated in real time on an intuitive display (perhaps a HUD?). After viewing the ADS-B demos I am encouraged but I don't think it is all the way there yet.

    Disclaimer: I am extremely biased in this area, due to the fact that my father was killed in an airline crash in April 1977 (read all about it in Chapter One of Air Disaster (Vol. 2), [amazon.com] by Macarthur Job). The main problem there - the plane flew smack into the worst part of a severe thunderstorm, which onboard weather radar showed as a clear spot. Both engines died, and despite having three airfields relatively close by, they attempted to land on a two-lane country highway. Admittedly both ground and airborne radar systems have come a long way since then, but they are still not enough. GPS might have let them know where the closest airport was in time, if not warning them off from the storm in the first place. If a real-time ground-based color Doppler radar display could be piped into the cockpit, along with accurate GPS positioning, I would think quickly developing weather systems would be much less dangerous for all classes of aviation. However, the bandwidth problems for something like this might be insurmountable for quite a while, despite this company's claims.

    #include "disclaim.h"
    "All the best people in life seem to like LINUX." - Steve Wozniak

  • Please transfer the money to the usual bank account. Pleasure doing business with you, Mr. Hussein!
  • The next generation of air travel:

    OnStar:How may I help you Captain James?
    Pilot:Um, yea, I just locked my keys inside the cockpit, can you unlock it for me?
  • GPS was designed primarily for the US military and is comtrolled my them. It was true up until a few months ago that GPS signals were deliberately "scambled" so that commercial receivers lere limited in their accuracy (usually to about 100 meters). This was intended among other things to prevent the "terrorist" from making a "poor man's cruise missile" using a Cessna, a GPS, and an autopilot. However the scrambling was recently disabled on order from President Clinton (though he reserves the right to re-enable it in an emergency). Commercial GPS receivers today can have an accuracy of 1-5 meters.

    Using GPS for air traffic control would only be a good idea if the US military can guarantee that they will not tamper with the signals in any way.

  • If it cruised along at say 50 feet above the ground at 150 miles an hour, there is no way it could be tracked and intercepted automatically, much less by a hand-held missile.

    It might be possible to have barriers on windows deploy quickly based on a radar system, but I don't think it would be possible to lock-and-launch that fast.


    --

  • What if you spoof your location so that it appears that your phantom aircraft is on a collision course with a real aircraft? One could imagine causing potentially serious disruptions that way.
  • I stand by my comment in general.

    A PAR approach is certainly an exception, but it is largly irrelevant. You do not normally use PAR to calibrate your altimeter, and it does you no good anywhere except right on the approach.

  • The altitude reported is taken from the aircraft altimeter. The transponder is part of the IFF system and cannot be considered to be RADAR in any true sense.

    If I remember correctly, a one digit error on the altimeter setting can equal 50 feet in altitude.

  • Especially since: * The ILS glideslope CANNOT be moved like they did in the movie. * All the planes would just fly to their alternates anyway. * The first officer of the plane that crashed would be reading the radar altimeter, if the GPWS wasn't doing it already. Diehard II was so unrealistic it was unwatchable.

  • Okay... the altitude is relative to the datum but isn't the actual computed altitude relative to the earth center?

  • Going to an autonomous system does not mean going to a lawless one.There would still need to be safety regulations and the need for enforcement.

    Today, however, you have the FAA in the role of both service provider to powerful monied interests (the airlines), and at the same time regulator of that service provision. They are already in a conflict of interest, and they already feel the pressures of the airlines, and pass that on to their controllers.

    Even if you keep a ground based control system (and there is still need for it in high traffic areas IMHO), there is no reason to keep it under the control of the same agency that does the regulation.
  • Add to this the complications of GPS giving height in meters and aircraft instruments giving height in feet,
    The last time I ran across a CPU that couldn't properly multiply metres by 3.2808399 to get feet, I returned it to Intel.
  • But first you'd have to stop talking out of your ass on slashdot. Need a long antenna on a plane? Run an insulated wire along a hundred-foot long section of the fuselage. You wouldn't have to install it in military planes, as they have better contact with ground installations and don't want to disclose their positions to the enemy.

    What you're truly forgetting is that while you're dealing with large expanses of land, you're dealing with fewer actual devices. The number of planes in a region would be easily dwarfed by the number of Bluetooth devices in a considerably smaller region. We don't have to worry about flying cars, yet.
  • UPS bought II Morrow, a fairly respected name in the avionics business about two years back I believe. That business was renamed "UPS Aviation Technologies"
  • Now as more and more dependance on this great GPS system starts to move in place, is it time for the United States to start beefing up the redundancy in the system. When peoples lives are riding on it every day, all day, what happens when a solar flare storm starts taking these things out? Hot spare's in the sky and on the ground maybe?
  • It's not just because of the intermittent inaccuracy of GPS that you'd want to keep radar as a backup- what if a solar flare comes along and knocks out several satellites over a busy flight route? Having a ground based backup system handy for such an event is a good idea. I would hope that someone would realize that before scrapping radar entirely.

    --
  • Each satellite has a unique "song" that is repeated every every 30 seconds--on the commericial side. The military "song" is on a different frequency and is much much longer, repeated on the order of days or weeks. There is a lot of encryption on the military side as well (naturally)

    A GPS unit knows the song for each of these satellites, and by this song, and knowing what time it is (and what timezone you are in), and knowing the general orbit of each satellite, it can figure out the distance between you and the satellite depending on what note each satellite is on.

    So I guess to fake out a gps, you'd have to know the 'song' of several of the satellites. I wonder if this would just jam the gps though...
  • I think 500m is many times closer that jumbo-jets fly to each other in mid-air

    Not in altitude. From 18000 feet to 30000 feet (IIRC), the minimum allowable vertical separation between two aircraft traveling in opposite directions is 1000 feet. I don't know what the minimum allowable horizontal separation between two aircraft flying at the same altitude is, but it's at least a mile.


    Since GPS is least accurate in measuring altitude, this might be an issue...
    --

  • Håkan Lans (Sweden) invented the "self-organising time-division multiple-access (STDMA) datalink" which ADS-B is based on.

    Scandinavian flag-carrier SAS has made a little bit of history with the first flight of a certifiable automatic dependent surveillance - broadcast (ADS-B) display in a commercial airliner. The move is a significant step along the long road to free flight. ANI was on board the 14 December [1996] flight from Stockholm Arlanda as the Swedish CAA performed certification tests on what is now called the MMI5000 (as in "man machine interface).

    For more info:

    http://www.gpc.se/founder/ [www.gpc.se]
    http://www.gpc.se/press/airnav1.htm [www.gpc.se]

  • DGPS uses an additional reciver which gathers data from ground based transmitters. The satalite system with the addition of a dgps recever is far more accurate. GPS w/ SA was 30 meters, GPS after SA was about 10 meters (from personal expierence) and DGPS after SA seemed to be about a meter accurate. Of course you need to be within range of a DGPS transmitter, but these could be installed near airports, where the accuracy really matters.
  • Using GPS for ATC purposes is a spectacularly bad idea. While the public may think that GPS signals are a natural resource, like cosmic rays, the fact is that GPS is first and foremost a military application and is still under control of the us armed forces. The armed forces occasionally do interesting things to the GPS signals, for field exercises and various tests, and these things would cause Really Bad Things to happen to ATC systems.

    For example, one test I heard about was a 5-mile displacement test, to see how well battlefield systems cope. The affect on ATC systems would be obvious.

  • Who is responsible? The pilot, that's who.

    GPS is just one more sensor, one more piece of the situational awareness puzzle. If a pilot bets his life on the performance of a single sensor and disregards the others, he deserves the result.

  • ...which was only emitting a couple of watts.

    The amount of radiation received from a GPS satellite is roughly equivalent to the amount of radiation a person in Los Angeles would receive from a night light in Chicago.

    A couple of watts is huge comparatively.

  • so what happens when the US decides to scrable the GPS signal like they did in the Gulf War?

    the delays board lights up like a christmas tree and stays that way for 2 months...?


    mov ah, 0
    mov al, 13h
    int 10h

  • [pedantic]

    Mr. Powers was shot down by one of fourteen V-75 missiles fired at his U-2.

    [/pedantic]

  • Cost is an issue, but should not be prohibitive for most. After all, since you fly out of Midway you already have a transponder and a radio and probably a bunch of other electronics. This system simply requires a GPS, a radio, and a display (and a computer, but embedded computers are cheap). Also, one could have some airspace where the system is not required, just like you have (or had, it's been a while since I was PIC) airspace with no required transponders.

    As far as distracting you from looking outside the cockpit... would it really be more distracting than all the fussing around you have to do today if you are flying IFR and dealing with ATC?
  • For example, if a pilot relies in this system and sees a plane on a collision course, or near collision course, he might turn, into the path of another aircraft that isn't showing up on the system.
    Easy enought to deal with. For aircraft that don't have the new system (and MOST won't for the first couple of years), the ground system coulD easily feed the heritage system date into the GPS datastream. Also, as someone else pointed out, Most aircraft that have advanced navigational systems also have older systems for backup (both in case of failure of the newer system and in case they are in an area where it isn't available).

    The idea of a '747 virus', IS intriguing. Fortunately, I doubt that aircraft will do software downloads in mid-flight.

    Captain, We're going to have to reboot.

    Simmons: How many times have I told you NOT TO UPGRADE WINDOWS WHILE WE'RE LANDING!?!?
  • This is inaccurate. First, GPS in common use as a primary nav system in the US. GPS is even legal for executing instrument approaches at hundreds of airports.

    You're right, I was inaccurate. I meant to say "sole navigation system."

    Herbie J.

  • And while the differences between Håkan's system and "DGPS" has already been pointed out, the main point about GP&C is really the self organising data link, that enables communication between aircraft, without any centralised control.

    And the US govt (not only FAA, since large corporate interests are at stake) attempts at hindering the adoption of this technology are well documented. The head pilot of FedEx aviation has even gone on record saying as much, after FedEx independently evaluated the competing technologies.

    -- I'm not a signature virus!

  • Ever heard of ATIS? ASOS? AWOS?

    They're all weather reporting systems. They play a recording, usually updated on the hour, that tells you all kinds of good stuff, like wind speed/direction, visibility, cloud layer height, and other good stuff. They also tell you what the current altimeter setting is at that airport. You usually plug in the nearest one and go. Or, you communicate with someone in Flight Service and they can tell you a setting to use.


    What do I do, when it seems I relate to Judas more than You?
  • Does GPS report altitude?
  • I don't know much about GPS in aviation, but I am a little surprised that this type of system does not already exisit.
    As a commercial/instrument rated pilot, I know exactly why this type of system doesn't exist: the horrendous bureaucracy of the FAA.

    Ever wonder why general aviation airplanes (which are inherently simpler machines than current automobiles) cost 6X-10X as much as an automobile? It's the FAA "standards" and "certification" that airplanes have to meet that causes this. To replace the little rubber grommet that holds the shoulder belt in place on a Cessna seatbelt is prohibitively expensive because of the PMA (Parts Manufacturing Authority) required. That's why the shoulder belt continuously falls off in many of the rental Cessnas I've piloted.

    In a Libertarian country, like America before the influx of European socialism in the 1910's, there wouldn't be an FAA. Instead, there would be certain interoperability standards (something like TCP/IP in the computer world) that everyone would adhere to, and airplane quality would be ensured by market forces and insurance companies.

    In a Libertarian America, ADS-B would have been adopted five years ago and would have become an international standard by now.

    If you'd like aviation to have the same affordability, accesibility and interoperability as the Internet, vote Libertarian. [lp.org]

  • Ha! 1-5 meters my ass.

    Somehow people assume that every clock is 100% accurate and that radio waves travel straight through that large layer of charged particles called the ionosphere.. Try 20 meters.

    If you want better than that, go differential.

    But, back to the story of the GPS guiding airplanes, I feel inclined to bring out the fact that the airplanes still must use the existing altimeter as GPS is absolutely horrible at altitude. Considering that GPS assumes that the planet is one perfect ellipsoid, one can understand the range of error.

    As for europe not wanting to base its airplanes on GPS, that makes perfect sense to me. The reason SA was turned off was because the DoD was able to demonstrate the ability of turning GPS on & off in specific regions. I would rather not like another country having control of whether or not my airplanes can tell where they are.

    --

  • Okay, so with this new system we're going to have pacman appearing on the screen? Jets telling other jets where they are? You're right, this is a James Bond flick waiting to happen! I can't wait to see what the evil guy with the nice hat will do when he finds out he just needs to "suggest" to the air traffic control system that none of the planes are where they're supposed to be anymore.
  • Read more about the history and articles about this at GP&C Systems International AB [www.gpc.se] and here are some interesting facts about Mr Håkan Lans [www.gpc.se], the inventor. He also holds one of three patents for the computer mouse and has a patent for color monitors for computers. Read more here! [www.si.se]
  • By communicating with the Air Traffic Controller, who gives him that information. Also, the ATC receives altitude information for an airplane trough the airplane transponder, wich calculate the altitude from the uncalibrated air pressure, the calibration being done in the ATC computer, ensuring the same calibration for every aircraft within is scope...

  • Hmmm (Score:4)

    by jaa ( 22623 ) on Sunday September 24, 2000 @07:51AM (#757852)
    crypic orders from the gound

    Indeed. I hat things that are har to undersand.

  • Remember, GPS can be off by as much as 500 meters (at least the handheld type; I hope what they're using is more accurate). If I were in charge of this, I'd keep the radar going, as a failsafe. I wouldn't want to see a midair plane crash over an airport involving 2 jumbo jets; that'd be absolutely tragic (I think it's happened once before, but maybe it was a jumbo jet and a smaller plane). I don't want to re-enact Airport '76 over my head!
  • However, the US military still has the ability to disrupt GPS reception locally.

    http://www.cnn.com/2000/TECH/computing/05/02/civ il.gps.idg/
    "... has demonstrated our capability to
    selectively deny GPS signals on a regional basis
    when our national security is threatened."

    It can be expected that the US will do this
    whenever they plan a military action. This
    effectively imposes a no-fly zone (for
    non-US-military planes) whenever the US plans
    action.

    Furthermore, if such a system is much cheaper
    and generally quite effective we may see flight
    organizations across the world transition to it
    with most of their training and capacity. They'll
    probably keep radar capabilities, but it may not
    stay up-to-date or with enough capacity to handle
    the air traffic volume of the future.

    So we are left with a situation where the world's
    air traffic may be dependent on the intentions and
    the ability of US organizations, and where US
    military needs take precedence over international
    air traffic control.

    There are other domains in which the US controls
    international efforts (in fact or in effect), and
    US military needs do tend to dominate local needs.
    So this isn't necessarily a change, but it's worth
    considering.
  • Firstly, it's going to be years before a move to a system like this really happens. Already, the lifespan of LORAN has been extended because the FAA admitted it needed to keep a backup in place. Also, LAAS/WAAS has been delayed quite a bit.

    To start with, GPS isn't accurate enough for precision approaches (mainly altitude), so LAAS (local area augmentation system) is needed. It's differential GPS. This gets the accuracy very high indeed - but it's implementation is delayed. So the ILS approach is going to be in use for some time. (ILS was designed many years ago. It works very well. It consists of two parts - a glideslope transmitter abeam the touchdown point, and a localizer, set at the far end of the runway, giving horizontal navigation. A receiver on the plane displays the aircraft's position on the loc/gs.) And if the ILS fails at the airport you're going to, you can fly to your alternate. I don't know what the probability of GPS failing is, but you lose it, and it's all gone. Something I wouldn't like to happen if the cloudbases are at 200 feet if I'm relying on it.

    GPS also has a bit of a single point of failure - it can be jammed quite easily. I know GPS jamming trials have occured in the US and UK. The beauty of the current VOR/DME system (which has been around since the 1950s) is that it's distributed. There are thousands of VOR (VHF Omnidirectional Ranges) around the country. If one fails, it's not such a big deal).

    The DieHard II Scenario: With IFR (Instrument Flight Rules) approved GPS receivers, malicious modification of the signals will not have pilots flying their planes into the ground. All IFR approved GPS receivers have something called RAIM: Receiver Autonomous Integrity Monitoring. The receiver can tell if it's getting bad data, and flag it. (Handheld GPS units do not have RAIM and will merrily display bad data - this is just one reason why they are not approved as a primary IFR navigator. You can use them as a backup to good old VOR/DME though).

    The other thing phoney about the DieHard II scenario is that instrument-rated pilots have been taught to cross-check. Basically - never trust a single source whether it's a NAV radio or a gyro. For example, when flying straight and level, you don't just stare at the attitude indicator (artificial horizon), you check it against other instruments. If the attitude indicator is showing straight and level, but the altimeter is unwinding, the turn co-ordinator is showing a turn, the DG and compass are turning, and the airspeed is increasing...you know you have a bad AI. If you're just staring at the AI and it quits, you'll wrap up in a spiral dive and do a JFK Junior. This is why sole-reliance on GPS is so abhorrent to virtually every pilot out there - relying on a single source goes against everything they have been taught about instrument flying.

    Expense: The cost of one GPS satellite is greater than the cost of keeping all the ground-based NAVAIDs (VOR/DME, ILS, NDB, LORAN) working for several years.

    Finally, I don't see ADS-B getting rid of at least secondary (Mode-C transponder based) radar. ADS-B is likely to be something that at least in the near term, only airlines can afford. There are approximately 10 times more light aircraft than airliners, and generally, the owners of the light aircraft fleet can't afford things like this until they have come down in price. At the moment, a decent panel-mount IFR-approved GPS costs $10,000 installed (Garmin GNS-430). Even the cheapest IFR-approved GPS receivers cost at least $4,000, and that money buys a hell of a lot of Avgas.

    Also, it is not trivial at all to make the National Airspace System work without the intelligence of a human (the air traffic controller) keeping it all together. Just start thinking of the issues of all those aircraft - and you'll see why they are trialling this sort of thing in Alaska where virtually no-one lives.

    And air traffic control instructions are hardly cryptic! It's pretty much in plain language ;-)

    "Bonanza four five Uniform, cleared to Angleton via radar vectors, climb maintain 3,000, departure frequency 134.45, squawk 4135, you're released"

  • Airplanes can figure out their own altitude and include it with the positional data they obtain from GPS.
  • You've got it backwards! The US turned OFF the dithering during the gulf war, because they did not have enough military GPS units, and had to equip military units with civilian units.

    GPS, even dithered, is accurate enough for air traffic work other than altitude. GPS, not dithered, is not accurate enough for landings, unless supplemented with differential GPS. Differential GPS works even with the dithered signal.

    Translation: NOT AN ISSUE.
  • The general rule of thumb for accuracy is that your lat/long will be about twice as accurate as your altitude. GPS receivers compute a figure of merit as to the expected accuracy of the solution- It is the residual of an over-determined set of linear equations. In general, the better the geometry of the SV (GPS satellite) constellation, the smaller your residual will be. The calculation of the altitude sucks because of the poor geometry of the calculation- you're trying to triangulate to a bunch of things essentially in the same plane, high above you (all in the +Z direction). You want to get some SVs in your calculation that are near the horizon, but the accuracy there will be off due to ionospheric differences, which is why the GPS system is a dual frequency system, the two frequencies give you ionospheric corrections. Unfortunately, no (commercial) handheld and only a few surverying receivers are dual frequency because only the Y code (encrypted P, or precise code) is on the second GPS frequency, and only the military has access to the crypto-keys for GPS. Some surveying receivers correlate between the two frequencies to determine the ionospheric correction factor, but this is not a trivial task: real time correlation between two 10 Mbit data streams.

    But what I was trying to lead to- differential or or not, you're still working with the same basic constellation (no subterranean SVs yet), and your altitude will always be half as accurate as your lat/long.

    What I'm unsure about is how much differential GPS helps out CA code receivers now that SA is turned off. With SA on, the effect was dramatic. For real precision, I don't know of any receivers that work well on a moving platform, since a large part of precision with a high quality CA code receiver is essentially just averaging. You have an inherent limit with a CA receiver since the raw code is a 1Mbit code.

    Most of this is recollection from a seminar I took from Navetech [navtechgps.com] about 3 years ago.
  • yes, but the handheld ones don't do it too accurately. I'd fire up my father's GPS, but I don't know where it is. I've seen the altitude reading off by 100 feet (I was out on the ocean, and it said -100 feet! I thought I was at sea level by definition!)
  • I don't *think* the dither was an encryption. It was just a way of misrepresenting the location of the satellite.

    Each satellite broadcasts a repeating signal (30second period for commerical) and based on what the current 'note' is in the signal, the current time, and the general knowledge of the satellite orbit, your gps figures out where the satellite must be.

    I *think* that the dither was just a random lenthening or shortening of a couple notes each time the song looped.

    no real encryption there. If you listen for an hour or so, you should be able to just average out the random errors.

    The military side is obviously encrypted, broadcast on two different frequencies (I think it is two songs), and the periodicity is something much longer than the comercial version. I believe it is on the order of days or weeks.
  • Hot spare's in the sky and on the ground maybe?

    There are spares already up there, ready to be moved into the proper orbit when needed. GPS is a vital technology for the US military- they have lives depending on it already. What bothers me is the dependence on just one technology. Yeah use GPS, but have a backup (VFR?) ready for when something gets screwed up.
  • Well the earth isn't exactly round. Also the sea has variations in height just like land has, they're just not as pronounced as on land. Your father's handheld gps is probably a lot different from the differential gps the planes would use. normal gps is accurate to about 100 m (300ft), differential gps to about 10m.

  • Does anyone know what the chances of the GPS system shutting down or suffering some other massive failure are? I haven't heard of any major loss of GPS service (outside of intentional shutdowns by the US military), but I also haven't heard much news about the overall fault tolerance of the system. Seems to me like the chances of losing a satellite or two are reasonably high, what with micrometeoroids, space junk, solar flares, and an extremly difficult maintenance process. With everything being fitted with a GPS receiver these days, the ability of the system to withstand a catastrophic failure seems pretty important.

  • Is this Håkan Lans' system? (Score:3)

    by Anonymous Coward on Sunday September 24, 2000 @08:25AM (#757864)
    The Swedish inventor Håkan Lans [orebro.se] (famed for among other things some nifty colour graphics patents that Hitachi bought a while back and a claim of inventing the mouse in the late sixties) has designed, constructed and tried to market a similar system (GP&C [www.gpc.se])for years, but the US aerospace lobby has been actively hindering him because they wanted to sell more of their old radar-based ATC systems to countries like India.

    Lans' system had an accuracy in the decimeter range (tenth of a yard) BEFORE the US DOD stopped fuzzying the GPS signal. This was achieved by a STDMA datalink (Self organising Time Division Multiple Access) and adding a few (there are currently around 30 of them covering Sweden, a country roughly the size of California) land-based transponder stations to the satellite coverage. The system basically use the land-based stations to enhance the satellite data. It is mature, operational and is an ITU and IMO world standard for large ships.

    On the terrorist/security aspect, I'd just like to point out that all civilian and military aircraft are required to carry and operate radar transponders at all times while in 'civilian' airspace so this system doesn't change anything in that respect.

    In short - it's a great system and everyone should use it; but it's hardly news.

  • A radar centered system has one point of failure, the radar (of course there is redundancy). 500 aircraft actively transmitting these signals means 500 points of failure. OTOH a failure of one GPS unit means one untracked aircraft. When the power on an aircraft is lost radar would still be required to see where it crashed, private pilots may not be able to afford the transmitters. Seems like a great idea but I doubt we will se radar completely replaced. Personaly I am of the belife that if you have 2 completely different systems that you depend upon your chances of survival are that much better.

  • Great! Trusted client problems in the sky. (Score:3)

    by dgris ( 454 ) <danie.grisinger@gmail.com> on Sunday September 24, 2000 @08:34AM (#757866)

    This seems like a really bad idea to me. It's practically an engraved invitation to someone to modify or create a version of the GPS system that spews bad data into the network.

    When will these guys figure out that you absolutely cannot, under any circumstances, trust externally supplied data. You cannot safely use any data from an outside source in your computations--and these guys are going to go and make our entire air infrastructure run on a trust model?

    The mind boggles.

    daniel

  • DGPS is unnecessary especially in flight- It will get you to sub meter level accuracy, and that is far more accurate than I hope air traffic control will ever need. Airplanes (esp. the big ones) already have very good radar based altimiters/ground speed indicators that will get them better altitude and speed than GPS really has a hope for. There may be some use for DGPS for control on the taxiways, but realistically, they should be keeping much further apart than 10M, so it wouldn't make a significant difference.

    These planes still have pilots, and they still and should have the final say over these technologies, especially when lives are at stake.

    The article this refers to mentions nothing I can find about DGPS. DGPS would just make it more complex and vulernable to failure, both incidental and intentional.
  • I got the impression that they were going to have some sort of master/slave system for moving the data around. The system gets a request from a ground station for position, plane transmits, ground station updates the rest of the planes in the area. I think that would explain the 150 mile range.

    However, you make a good point... If this is going to be a real time system, it will need to receive, process, and transmit the data very, very quickly. In a busy flight center like NYC or Atlanta, things could get overloaded in a hurry. Also, I'd like to see how they handle a new plane arriving in the airspace. They'd have to have some sort of announcement window that would allow new planes to enter the system and a good way to deal with planes that drop off (when to stop tracking).

    Of course, if this is just a peer-peer system, the chances for saturation are very, very high.

    Also, as far a powerful transmitters, remember that airplanes have a major advantage over ground based transmitters: height. Generally, you can communicate over very long distances with very low power, only because you are 10,000 feet above the earth.

  • after all the 'toasters running linux' stories on /. you would expect there to be some mentioning of linux in some way whether relevant (offtopic) or not....

  • Or heck, make it a remote controlled jet! Imagine a 6-8 foot long jet travelling at 120-150 miles per hour aimed at the white house. It would be unstoppable.

    No, it wouldn't be unstoppable. It could be easily shot down. Germany tried precisely this tactic when bombing London back in WWII, and large numbers of these planes were destroyed by ground-based artillery before they could detonate upon impact. Why do you think Germany started switching to its V-2 rocket campaign? Those suckers always reached their targets (though other defenses exist today).

    If you're going to do something as rash and stupid as try to blow up the whitehouse, do it with a ground-based tactical nuke (suicide, but effective). 120mph is chickenfeed.
  • There is a major problem with the TCAD systems, not all aircraft have one. The Airliners do, but us GA Folks don't becaus the TCAD systems cost far to much, 50K+. Considering that many GA aircraft aren't worth that much it does not make much sense to do that. And in general the ATC system does a very good job of keeping people apart in the clouds. Must midairs happen in Visual weather around an airport.

    The Cure of the ills of Democracy is more Democracy.

  • So, what's to stop me setting up my own transmitter to overload a given area (say, the 70,000 square miles around my house) with a million fake planes?

    Nothing. Hack away. They will ignore it and use the old system of identifying an aircraft based on transponder code, instead of GPS code. It'd be an inpressive hack to be able to spoof millions of fake aircraft to the radar system. And contrary to the extremely miselading title, radar ain't going away.

    Or what if I know the id code of a plane before it gets to me, and I start broadcasting that I'm that plane?

    Well, since the other plane would be in communication with ATC still, it'd be kinda obvious that something fishy is going on. Then, the controller would proabably request that the pilot squawks his transponder with the assigned code that they were given upon their IFR release. It would be cleared up which one the real aircraft was, and they would track that aircraft.

    What happens when it arrives?

    They set it up for an approach, since the aircraft in question has been working in the system and is being tracked. If you were early, they would proabably request that you go into a hold until a specified time, or if they cleared you to land, someone is going to eventually notice that there isn't a plane on the ground, and Cessna 23FOO is still communicating with the air route traffic control center...


    What do I do, when it seems I relate to Judas more than You?
  • This was intended among other things to prevent the "terrorist" from making a "poor man's cruise missile" using a Cessna, a GPS, and an autopilot.

    Only works so long as the "terrorist organisation" has no kamakazi pilots.
  • As best I can tell, we already do. One ATC operator could send a plane onto a collision course with another, and then there would be nothing to tell the planes not to. We implicitly trust the towers. If we do this, we just shift to a system that has DIFFERENT, but probably neither inherently more nor less, problems. The problems change from many potentially dishonest operators to very few operators, but many potential crackers. Navigation has had trusted client problems forever (lighthouses, whatever the land-based radio location system was, could all be messed with). I don't know of any recorded case of a problem. Admitedly, we have many more people who would want to mess things up, but I don't think that this is a new problem.

    ---
  • ADS-B isn't intended to replace controllers or radar. It is primarly used where there is no radar coverage, to supplement radar. As an example, trials were carried out over part of the North Sea oilfields. You don't need a powerful computer to handle huge numbers of flights. I worked on the software for the North-America to Europe corridor, which is the busiest area in the world. The computers aren't as powerful as you think; they don't need to be.
  • This system simply requires a GPS, a radio, and a display (and a computer, but embedded computers are cheap).

    FAA Approved (which it would HAVE to be) computers are NOT cheap. Do not get any illusions of this technology making avionics stacks cheaper.

    For example, the Garmin GNS 430 costs around $8000. It's an IFR-approved navigator. By the time you add installation, you're talking $10,000. On the other hand, the non-certified Garmin GPS 295 ( a handheld with the same display, and most of the features of the -430) costs $1400. And even that's expensive for what it is.

    Cheap and airplanes don't go together. That's why the avionics stacks of most light planes are full of old radios without even simple 7-segment digital displays: the owners can't afford to buy the latest whizzbang radio and the old ones still work very well. There are a lot of old mechanical tuned King KX-170Bs out there. And it's not surprising when you consider the cost to upgrade your stack to what new Cessna 172s coming out the factory is around $40,000. And $40,000 is greater than the value of a lot of light planes out on the ramp today!

    If it's FAA-certified, it's expensive - often prohibitively so.

  • My airplane is about 30 feet long. How do I run that wire???
  • There are certainly recorded cases of problems in the lighthouse era. Certain charming people would set up fake lighthouses to lure ships onto rocks, then steal the cargo & murder survivors, if any.

    It just goes to show that there have always been unscrupulous people willing to subvert security systems. Bringing fancy electronics into it doesn't change the fundamental problems.

  • Germany tried precisely this tactic when bombing London ...

    That's not comparable. First of all, an full-blown airplane is a lot larger than a little 6-foot model. Second of all, this is not war we're talking about, but just a single target in the middle of city. The white house (or pick any other target) does is not going to have anti-aircraft guns at the ready.

    120mph is chickenfeed.

    That's 176 feet per second, or 2 miles/min. I guarantee you that if a little 6-8 foot model zoomed by 30 feet off the ground at that speed, you would not think it was chicken feed. Imagine me launching it from two miles away. 1 minute later it would hit the target.

    do it with a ground-based tactical nuke (suicide, but effective).

    Well, the point is the low-cost. The hard part would be to get lightweight explosives that would pack enough explosive power but would fit inside a model.


    --

  • Obviously, you didn't read his comment close enough. He wasn't talking about human error. Right now, you have about as much logic as HAL-9000 did when he "reported" the error with the dish's PCB.
  • As best I can tell, we already do. One ATC operator could send a plane onto a collision course with another, and then there would be nothing to tell the planes not to.

    Not exactly. The Traffic Collision Avoidance System (TCAS) is an aircraft-to-aircraft system that works from a multitude of input data (as practically every on-board system does) to determine with the largest precision & accuracy the location of the airplane which is then broadcast out to other TCAS receivers in an attempt to avoid collisions.

    Each TCAS receiver classifies incoming data in various levels: No Threat, Proximity, Traffic Alert, Response (?) Alert - which in aviation lingo translates to TAs (Traffic Alert) and RAs (Response Alert). The TAs and RAs are the only things of significance to the pilot since they are potential collisions (especially the RAs) - hence their color on the navigational and primary flight displays: yellow for TAs and red for RAs.

    Based on his current flight (ascending, descending, level) the pilot keys in the TCAS system to show him only tracks of interest - if he's ascending, it makes no difference what's below him, etc.

    This system is based on ground location data (from a multitude of sources, all based on radio towers located on the ground, with known positions) GPS data and differential GPS (where available - the only flight system I'm aware of that uses this in the US is the Boeing 777 with Honeywell's flight management computer (FMC) and Honeywell's large format display systems (LFDS) - similar to what was posted about the new shuttle display systems here on /. not too long ago.

    Differential GPS is primarily only used for approaches, I believe - since that's the only time more precision than GPS is necessary (and even after the military scrambling of GPS ended, more precision is necessary to land the plane than military GPS provides) - 10 meter accuracy (or whatever it is exactly) puts you on the runway or off of it - not nearly enough for the autoland systems to feel comfortable with!

    My reference: ex-avionics engineer for Rockwell Collins. That said, none of the statements made (express or implied) reflect the position, past or present, or presume to be 'expert advice' in any matters avionic, of Rockwell International Corp.

  • GPS is accurate to within 10-15meters with a hand held Garmin or Magellan, to get much better than 7m (autonomous) you need data from a ground based base station. (5mm is possible with a survey grade system, and a base station within 10km)

    Europe is building their own system called Gallileo (deployment for 2005), Russia still has it's Glonass system flying. A major contractor for the European system is Novatel out of Calgary Canada (go figure)

    In 2005 three more channels will be available from the next generation of American SV's so accuracies should improve.

    GPS signals are difficult to but not impossible to fake. Most high grade receivers include anti-spoofing technologies to minimize this threat. it could be blocked but not easily faked

    ADS-B is supplemental to exisiting radar systems, so it should improve exisitng navigation, as long as governments dont get lazy and give up on radar stations.

    I don't know much about GPS in aviation, but I am a little surprised that this type of system does not already exisit.
  • Comment removed based on user account deletion

  • Not in altitude. From 18000 feet to 30000 feet (IIRC), the minimum allowable vertical separation between two aircraft traveling in opposite directions is 1000 feet. I don't know what the minimum allowable horizontal separation between two aircraft flying at the same altitude is, but it's at least a mile.

    Since GPS is least accurate in measuring altitude, this might be an issue...

    OK, let's think about this. The issue in question is supplanting radar with GPS. Apparently, you think that planes now get their altitude from the control tower. In fact, each plane has a device known as an altimeter. Miraculously, this device will continue to work even if GPS is installed in the plane.

  • Anyone read _Flare_ by Roger Zelazny and Thomas T. Thomas? One of the sub-stories describes how a jet nearly wipes out because it's GPS nav system is disrupted by a solar flare.

  • Cool, but not that cool (Score:3)

    by groundclutter ( 227351 ) on Sunday September 24, 2000 @08:49AM (#757890)
    There are a few things that one should keep in mind.
    • This particular implementation is curently being tested in parts of Alaska where there is little to no radar coverage. While the system might not offer all the features of radar coverage, its a lot better than what's there now.
    • All GPS's certified by the FAA for use in aircraft report altitude. In addition to use the GPS data to compute the altitude, many GPS units can also connect to the altimiter for altitude data just as MODE C transponders do now. Since selective availibility has been turned off, gps computed altitude is very accurate.
    • Having the GPS report the aircraft's position for purposes of aircraft seperation is just one small part of this. The UPS technology allows for two way data tranmition between the aircraft and the ground. This is useful for uploding weather data to aircraft, something that is only currently available as an option on very high end corporate and commercial jets. The GPS simply says, "I'm here" and the bandwidth usage is minimized by only sending the data for the local area (as well as any pireps, sigmets, or other timely information). For what its worth, you can also check your email.
    This system was never intended to replace ground based radar as a means for directing air traffic. While a single failed transponder can cause problems in the current system, a failed gps unit on a single aircraft in a GPS only system could be catostrophic.

    If you think this is cool, take a look at http://www.flightexplorer.com [flightexplorer.com]. it allows you to track flights in real time. Not just scheduled airliner traffic, but your friend in his Piper Cub.

  • I have a Garmin GPS III (not sure if the III+ acts identically), and I have held it to the window of an airliner. It nicely registers 525mph landspeed, along with a realtime map showing ground landmarks. Software copyright is 1997.

    Civilian GPS units are not shielded from producing antenna echo, so turn it off when the nice crewmembers tell you to turn it off. In brief, receiving-only units like GPS need to amplify the weak incoming signals, and in non-aircraft units, some of the amplified signal leaks back out the antenna, which can interfere with other nearby sensitive devices like the airplane avionics.

  • Re:Is this Håkan Lans' system?(no, it's common) (Score:3)

    by GoRK ( 10018 ) on Sunday September 24, 2000 @12:31PM (#757896) Homepage Journal
    Or should we say it is *a* differential GPS. DGPS is a standard system that does not come close to the 8" or so accuracy of the Lans system. (The best i've ever seen with DGPS even since SA was turned off has been 3ft.)

    Basically the lans system used DGPS data (diference in actual vs reported position from each bird) plus clock error data plus a higher density of differential stations. Of course this required expensive atomic clocks at each differential station and a very complicated (though not terribly expensive) reciever, but it certainly wasnt DGPS. And YES the US did try to supress installations of that system in this country as it took gps out of government control (e.g. if you lost satellite reception entirely, you could still possibly deduce your position from land-based recievers alone) where with DGPS you still had to have satellite communications.

    ~GoRK

  • I've often wondered how long it will be until someone puts a computer and a GPS into a remote controlled airplane, loads it up with explosives and sends it on its way. In the past, the accuracy of the GPS was probably too low, but I believe the current system is now 3 meter accuracy, which would probably be enough (along with some attitude sensors so it could stay level).

    Or heck, make it a remote controlled jet! Imagine a 6-8 foot long jet travelling at 120-150 miles per hour aimed at the white house. It would be unstoppable.


    --

  • Today, you can trivially override or jam the broadcasts from the air traffic controllers. This has happened and is considered a serious threat.

    So setting up your own transmitter is just repeating an existing threat. The same techniques that are used to catch the folks jamming ATC will catch you.

    Furthermore, since aircraft are most interested in signals from other aircraft close to them (which are the ones that represent a collision threat), your jamming would only be significant to aircraft very close to you.

    So, overall, I think that the GPS autoreporting system can be significantly more jam-resistant than the current ATC system.
  • Sorry, but that answer doesn't cut it for me. Sure you can interfere with the existing air traffic control system with a cheap radio. Do you want to perpetuate this sort of vulnerability into perpetuity? If we're going to spend gazillions putting in a new system, how about we make it more secure than "it happens"?
  • There is no hole at the artic. The sats only go up to about 60 degrees but thats far enough to see at least 7 of them most of the time at the poles. Right now there are at least 12 visable at the north pole, 10 at the south.

  • Re:GPS reports altitude? (Score:3)

    by kugano ( 84704 ) on Sunday September 24, 2000 @09:20AM (#757936) Homepage
    For several reasons. First of all, on smaller aircraft, standard altimeters require constant attention from the pilot. The altimeter gets its data from comparing the pressure of the air outside the plane to the pressure of the air on the ground, and then doing some math to figure out the altitude. The problem is that the altimeter has to know what the pressure on the ground is. This is achieved through a small dial on the side of the altimeter that the pilot has to adjust every 15 minutes or so to keep it accurate. As you can imagine, this is prone to error, and added workload for the pilot.

    Secondly, standard altimeters have a tendency to break. I've only been flying for a few years and have already run across several dead or dying altimeters that have required me to change my flight plans.

    So I think GPS-based altitude (and this GPS system in general) is a long-needed treat for the aviation community. There are a few hurdles that need to be crossed, such as avoiding abuse of the system (I believe someone else already posted about this) and redundancy. But if they can get the flaws worked out of the system on the ground, I for one will be happy to fly with it in the air.
  • This is stupid. I'm sorry, but if one plane's GPS goes offline, you instantly have no idea where it is, except a very rough estimate, unless you still have radars and air traffic controllers active.

    Also, as for getting rid of ATC's... They're like traffic cops. Without them, you'd have no way of resolving who gets to go where, when, in the cramped airspaces around a given airport.

    Putting GPS on every airplane is a great idea for a bunch of reasons. For example, the black box could not just emit a pulse, but it could emit a pulse with its exact location. It will, in fact, make air travel somewhat safer. But it won't replace the need for towers, radar and controllers, and it's stupid to bill it as such. Just once, I'd like to see an article without hyperbole.

  • Uhhh. It's a little more difficult to get away with blowing up a fixed piece of equipment than it is to buy some inexpensive gear and set up shop somewhere within thousands of square miles. You wouldn't even need to stay with it - activate it with a timer and be well away by the time the authorities track it down. Then you start up the next one ...

    Having redundant base stations does you no good if somebody has set up some equipment to lie to them about what's really out there.

  • One thing most of those criticizing the GPS based system miss is that the current system greatly increases aircraft density, which itself leads to collisions. The Air Traffic System has fixed locations in the sky which aircraft must go to as part of standar approaches and departures. Furthermore there are fixed, narrow corridors. Thus many aircraft (especially small aircraft) are focussed into small parts of the airspace, and they do collide there!

    With an autonomous system, without human controllers, such fixed points and routes would be unnecessary. Aircraft could go point-to-point, reducing density and collision probabilities. Furthermore it would increase traffic capabilities.

    As a former pilot who had to spend way too much cockpit time dealing with air traffic control regulations and navigation, rather than watching for traffic and flying to a destination, I think that the current system sucks!
  • Actually, for a system like this the FM capture effect may be useful. An FM receiver can lock onto the stronger signal, ignoring weaker ones. This is why AM is used in aircraft voice radio -- so weak signals are not hidden.

    In this case, the stronger/closer signals are more important, and will reduce accidental jamming problems. The power at the antenna has to be similar, of course.

    The system by itself does work best when all aircraft use the same system. It does not rule out other systems being used; an aircraft can also be monitoring existing systems or even optical monitoring.

  • I dunno... i mean sure if we had something scalable like GPS with as many backup systems as ATC, we'd all be flying... but how reliable is it?

    ----

  • Re:GPS reports altitude? (Score:3)

    by SuperBigGulp ( 177180 ) on Sunday September 24, 2000 @07:55AM (#757950)
    It can, since all you are really doing is just triangilating on another axis. Most of the low-end consumer devices can report alt., although the accuracy seems to vary from bad to not-so-bad. High end devices should be more likely to provide accurate alt. info, although it really depends on how many satellites are in "view" (the more the better).

    I could see how GPS would be good enough to navigate by, but probably isn't good enough land by (yet).
  • Is the EU (European Union) still refusing to grant permissions to European airlines to use the GPS sytem?

    Of course you sort of have to understand them since GPS is partly controlled by the American Ministary of Defense (or is that just a myth)?

    But still superior technology should well be used.. Me thinks..

  • Peer to Peer Air Traffic Control (Score:3)

    by quonsar ( 61695 ) on Sunday September 24, 2000 @02:21PM (#757955) Homepage

    ...developing a new air traffic control system called ADS-B in which the aircraft broadcast their position, altitude, and airspeed to each other...

    Ahhhh! Gnutella for Gnavigation!

    "I will gladly pay you today, sir, and eat up

  • Re:This is one step forward and two steps back. (Score:4)

    by SeattleDave ( 236077 ) on Sunday September 24, 2000 @07:59AM (#757957)
    The fuzzy factor imposed by the US government to thwart military uses of their GPS system was lifted on May 1 of this year (see http://abcnews.go.com /sections/tech/dailynews/gps_000501.html [go.com]) - making the use of GPS 10 times more accurate. So, GPS, even for folks like us, is now accurate to within 20 yards. Plus, airplance don't have too many things in their way to block signals from those satellites.

  • Funny you should mention Goldeneye ... (Score:3)

    by tjwhaynes ( 114792 ) on Sunday September 24, 2000 @07:59AM (#757959)

    I think you picked the wrong James Bond movie - especially given that "Tomorrow Never Dies" plotline involved changing the syncing of the GPS satellites in order to send a ship into Chinese waters to start a war. Obviously some sixth sense working but only on half power :-)

    Cheers,

    Toby Haynes

  • This is hardly a novel concept. It is known as differential GPS and is widely used in marine navigation, and has been for years. The idea is that a fixed location station broadcasts what it is receiving from GPS, allowing other stations to correct for errors. One broadcasts both the digital data and the signal phase, allowing very high accuracy. It has been proposed for aviation, and I believe is in use for some landing systems.


    Rather than imagining a conspiracy by the U.S. aerospace lobby to prevent a foreign technology from coming in (when, after all, consumers all over the US are already using an equivalent technology), realize that the vested interest against such a system is the air traffic control system, in the U.S the FAA. The FAA has, over the decades, significantly increased its air traffic control responsibilities, to the detriment of general aviation. They have a large bureaucratic fiefdom at stake here that they do not want to lose.

  • Even with radar, altitude has always been self-reported (Mode C). GPS civil mode will now have 20M accuracy, which is much better than ATC radar resolution in any dimension. But backups of some sort are always needed. For example, an Air Force ground test inadvertently took out all civil GPS for at least a few days, over upstate New York, as reported at the time by Aviation_Leak mag. It was rather diffcult to find the jammer, which was only emitting a couple of watts. Then again, as it now stands, the backup for ATC radar outages (whatever the cause) is verbal position reporting by radio.

  • Off-the-shelf commercial GPS does elevations too. Now that they've taken the dithering off the satellite signal, you can get high-accuracy elevations, not just to the degree needed to keep airplanes off the sides of mountains, but to land surveyor's accuracies, nice and fast.

    My big fear is that this airplane guidance system seems to be distributed, so if the GPS system in one plane goes on the fritz, then all the other planes will think that one plane isn't where it is; you can see the danger in that.

    Yours WDK - WKiernan@concentric.net

  • When one aircraft stops transmitting, it still will be avoiding all the other aircraft which are still transmitting. When one aircraft loses both transmit and reception, it's out of the system and back to how it is right now.

    And if you're going to argue poverty of small aircraft, remember that right now most of those are invisible anyway. Those that don't have radar transponders aren't on most radar screens. They're bopping around on visual...of course, they're also down in the lower altitudes and away from the commercial aircraft.

  • i beleive what youre thinking of is that the government didnt allow the gps people to make it more accurate than a certain amount, but it can actually be accurate to like 3 meters, or something like that. the government also lowered the limit sometime in the past year i think.
  • A few things in the article leaves me with a few concerns over how expensive it'll be.

    The first thing that concerns me is the ranges, 150 mile radius. That's roughly, 70 thousand square miles, how many planes can you get flying in that area? I'm not even going to consider how many you can get if you take into three dimensional space.

    With this amount of space to monitor, and all those aircraft, you're going to need two things. The first you need is a fast computer to keep track of all these aircraft. Second you're going to need a damn good radio, and modulation techniques to have broadcasts between all those aircraft without having all the data garbled with collisions.

    For the system to be effect you'd have to install it on all aircraft, how long is that going to take? Because if one aircraft, or even a handful of aircraft are flying through the area and only they and the air traffic controllers know about them, the main selling point behind this system isn't really worth while. You still need to rely on ground controllers to tell you who's out there.

    For example, if a pilot relies in this system and sees a plane on a collision course, or near collision course, he might turn, into the path of another aircraft that isn't showing up on the system.

    For the system to handle 150 mile radius, you need a powerful radio, or large antennas, (both of which you probably won't find in private planes). You'll also need to install it in military aircraft, remember the F-117 that buzzed the airliner a few weeks ago? This of course costs more money and more tax dollars.

    I don't see how this system will be as effective as they're promising without it being installed in all aircraft that will be flying through an area. It will help, I'm not denying that, but it will not remove the need of ground controlers and their radars. It won't even lessen their need at all.
  • ""UPS Aviation Technologies, a subsidiary of UPS..."

    Waaaaait a minute, you mean that UPS is doing this? THE UPS? The "We run the tightest [l]ip in the s[l]ipping business" UPS? This is too funny. And they can't even track the location of a simple package!

    Personally, I used USPS Priority Mail with the $0.35 tracking tag and insurance to ship my Western Digital drive for RMA.

Slashdot Top Deals

"May your future be limited only by your dreams." -- Christa McAuliffe

Close