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Guiding Air Traffic Sans Radar With GPS
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 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 and That Scene(TM) at the start of Terminal Verlocity even less believable. (Note: If you havn't seen 405 the movie yet, follow that link!)
Michael
...another comment from Michael Tandy.
"Goodness me, how unlike the FBI to abuse the trust of the American public." -- The Onion
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?
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Meep meep
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.
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,
You can read the entire article for more details.
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), 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
#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!
EagerEyes.org: Visualization and Visual Communication
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?
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.
I have a positive modifier on Troll. When I mod someone Troll their karma should go UP!
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.
--
Sometimes it's best to just let stupid people be stupid.
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 have a positive modifier on Troll. When I mod someone Troll their karma should go UP!
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 only good weather is bad weather.
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.
Defecation occurs.
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.
Oolite: Elite-like game. For Mac, Linux and Windows
Okay... the altitude is relative to the datum but isn't the actual computed altitude relative to the earth center?
Defecation occurs.
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.
The only good weather is bad weather.
Free Software: Like love, it grows best when given away.
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.
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brave little toaster
"Remember, don't try this at home until the statute of limitations has expired."
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...
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...
--
Disinfect the GNU General Public Virus!
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/
http://www.gpc.se/press/airnav1.htm
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.
--- only for the squeamish
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.
Defecation occurs.
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.
Defecation occurs.
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
mov ax, 13h
int 10h
[pedantic]
Mr. Powers was shot down by one of fourteen V-75 missiles fired at his U-2.
[/pedantic]
Defecation occurs.
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?
The only good weather is bad weather.
The idea of a '747 virus', IS intriguing. Fortunately, I doubt that aircraft will do software downloads in mid-flight.
Free Software: Like love, it grows best when given away.
You're right, I was inaccurate. I meant to say "sole navigation system."
Herbie J.
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?
Still not dead.
Does GPS report altitude?
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.
The IPCC has purposely engineered a massive scientific fraud.
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.
--
Care about electronic freedom? Consider donating to the EFF!
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 and here are some interesting facts about Mr Håkan Lans, 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!
Indeed. I hat things that are har to undersand.
Never meant half of the things I said to you. So you know, there's a half that might be true - G. Phillips
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!
"Ancillary does not mean you get to rule the world." --U.S. Circuit Judge Harry Edwards, speaking to the FCC's lawyer
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"
Oolite: Elite-like game. For Mac, Linux and Windows
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 only good weather is bad weather.
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 about 3 years ago.
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.
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.
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.
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
All I needed to know in life I learned from
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.
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.
"Well, good luck finding a judge that doesn't run a bestiality site."
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.
The Cure of the ills of Democracy is more Democracy.
Erlang Developer and podcaster
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.
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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.
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.
Oolite: Elite-like game. For Mac, Linux and Windows
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.
- Alan
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.
"Ancillary does not mean you get to rule the world." --U.S. Circuit Judge Harry Edwards, speaking to the FCC's lawyer
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.
One of the primary benefits of having position information available in radar-inacessable areas is that it allows shorter flight times between hemispheres. I believe the FAA has supported trans-artic flights via this method for several years.
Your monitor is staring at you.
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
well in that case he would have crashed into it without the system as well wouldn't he ?
just because an aircraft would have a new navigation system installed doesn't mean that it gets rid of the old one. You should see how many archaic shit is still in new aircraft these days to provide some backup in case the newer shit fails
Iraq has anti-aircraft missiles of the same type Cuba used to shoot down Gary Powers in his U-2. They have been given boosters and turned into ballistic missiles with a 140 mile range. They did this field conversion because they are out of scuds. Their potential warheads consist of Anthrax, Nerve Agent and Radioactive Medical Waste. I'm sure you will note that the apex of a 140 mile ballistic trajectory is much higher than a 26 mile geosync orbit. All they need to do is reverse engineer a GPS receiver to make a GPS transmitter. They are ten smart guys and 60 dollars (Mitac Metro Guide Car GPS Navigation System for Portable PC Car Navigation System for Portable PC, Incl.-GPS system, software, mapping software(10cds of entire US). $ 60 ~pricewatch) away from cleaning our clocks. Try not to ever underestimate your enemies...
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.
- 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. it allows you to track flights in real time. Not just scheduled airliner traffic, but your friend in his Piper Cub.
I see some potential danger here. Since the system relies on the aircraft to report its position and other data, someone with malicious intent could dummy up that data and make it appear that a nonexistent aircraft is present where it actually isn't. Having the data from other aircraft available, you could make it appear that another plane is on a collision course. You could potentially put dozens or hundreds of dummy planes in the area, making the system useless for air traffic control. Someone who wanted to disrupt our air traffic system would have a great tool at their disposal.
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.
[
I read it. The statement still stands. GPS doesn't guide the aircraft. Autopilots on most (if not all) GA aircraft do not follow terrain. If the pilot leaves a dark spot on some mountain top, it's his fault.
Defecation occurs.
>Or heck, make it a remote controlled jet!
It has already been done, a long time ago, by the former Soviet Union. The King Fisher missile was basically a MIG jet strapped to a bomber. I believe it was an over the horizon type of weapon and used terminal guidence supplied by low flying helicopters. (Hormone-A chopper?) The principle target at the time of development was U.S. carriers. It's speed was measured in Machs.
Also, GPS/Model Airplanes has been a military hobby for both the U.S. and the Isralis. I think both countries have some very innovative systems. The U.S. even has pocket versions that will allow a Company commander to deploy a disposable tiny plane so she can see beyond a hill or around other obstacles. Something similar was envisioned by Vernor Vinge in "A Fire Upon the Deep."
--Peter
Because inertial navigation systems are based on
;>
:>
technology like calibrated laser-ring gyros, and
cost a great deal of money to install and
configure. They rely on vastly more expensive
avionics, as well. They are internal, but must be
set before flight.
GPS works fine. Heck, VOR/ADF/DME works great.
Even dead reckoning works well, too. Radar is
good, Loran-C is functional, and you can certainly
never have enough navigational capacity.
It's amazing reading the reactions of the general
public to stories like this. If people knew how
things really worked, they'd pee their pants every
time they flew on a commercial airliner.
It's the pilots, not the equipment, that keeps you
alive. Remember that, and respect them.
-Kysh
--=:: Wings and tail and snout and scales of blackest night
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
Doesn't the military currently limit GPS implimentations to speeds below 900km/h?
Argh.. you're not a pilot, are you?
/.ers. :>
Be terrified: There are A LOT of airplanes out
there flying above you that are Not controlled by
ATC. Infact, they're being controlled by, horror
of horrors, the pilots. Didn't you see
Independance Day?? Do you know what can happen if
the PILOT is actually allowed to fly? Wow.
On a more serious note, there's a lot more to
flying than travel. Air traffic control isn't like
a traffic cop, air traffic control provides
traffic coordination, seperation, and above all,
assistance to pilots. They do not make the rules,
they follow the rules and assist pilots as those
rules require. They're a cool bunch, though.
But if air traffic control didn't exist, traffic
would still be manageable.
From the passenger's point of view, I guess I can
see where you're coming from.. but it's not an
educated point of view. If you want real answers,
ask a pilot, or even an air traffic controller.
Don't ask
-Kysh, a pilot.
--=:: Wings and tail and snout and scales of blackest night
With luck, though, they'll accidentally go to salshdot.
-Pete
At least I'm not the only person to see this kind of problem. Why DoS Yahoo, when with this kind of technology, a laptop, and a decent radio transmitter, you can DoS attack LAX, O'Hare, JFK, or Dulles. Think air traffic delays are bad now? One hit against something like this, and (courtesy of the delay effects that spill from hub to hub acros the country) you could effectively choke air traffic to ~20% of current capacity.
Is it just me, or does this sound like a REALLY STUPID IDEA?
Just as a note, I'd like to point out that even if they used the inaccurate version of GPS (+- 500 meters), it would still be very accurate for keeping planes from hitting each other, because all the inaccuracies in an area are the same... all the planes would be off by the same amount, because they are using the same (inaccurate) GPS satellite signals.
Of course, since the US is no longer encrypting the last digits of the signal, even ordinary cheapo handhelds are accurate to within a few meters now.
And my soul from out that shadow that lies floating on the floor
"I will trust Google to 'do no evil' until the founders no longer run it." Hello Alphabet.
Buh-dum-bum. Thank you ladies and germs.
-Pete
Unfortunately, everyone still uses ELT's. It doesn't look like anyone will be changing any time soon. I don't know of any ground teams that have the equipment for anything other than 121.5 and 243 MHz. (My personal equipment will, but the squadron equipment doesn't. =])
You might want to discuss that with a few of the helo pilots the Soviets lost in Afghanistan. The Afghanis got most of the their helo kills at altitudes under 1000 feet, usually in low-altitude attack paths.
That, btw, is the reason the Sov's wound up putting a "4000 ft AGL" hard floor on attack helos - they just lost too many down low.
Oh yeah - and remember, the technology has just gotten better since then.
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.
--
Sometimes it's best to just let stupid people be stupid.
What makes you think the inter-airplane communications protocol is going to be so easy for you to broadcast? What makes you think you're going to be able to trick the base station into thinking you're a million planes?
The only thing I can think of is a jamming procedure, and you can do that today with radar!
Obviously, the GPS signal will be acquired by the planes and/or base station from the real GPS satellites. Faking this signal isn't easy to do, or else it'd be done all the time today. And we all know that it's not.
After acquiring positional information from GPS, the units will obviously re-package the information onto an encrypted channel of communication, utilizing extra security and tecnologies such as DSSS (ooh, buzzwords!) and other shit that I have no idea exists.
And this "single point of failure" bullshit about GPS satellites going down. Well, what happens today if this giant radar tower stops working? Mass fucking chaos. At least there are multiple points of failure with the GPS system; the chances that you're not going to see at least three satellites above the horizon is much smaller than a radar system at an airport (which are horribly old and antiquated anyway) going down.
- Mike Hughes
The dangers of knowledge trigger emotional distress in human beings.
GPS is owned by the Department of Defense, and run by the US Air Force and US Navy. I don't remember exactly who runs it, but I think it is 2SOPS or 3SOPS.
I can strap 10 pounds of explosives to an airports radar tower and "make the system useless for air traffic control". You can have redundant base stations with the broadcast idea, so that if one of them is disabled, the rest can simply kick in. Backup power and extra security can help, too.
- Mike Hughes
The dangers of knowledge trigger emotional distress in human beings.
As far as I know, although this may have changed very recently, the US FAA still doesn't allow US airlines to use GPS as a primary navigation system, but instead only as supplementary system. All airliners are still (and will be for quite a long time) equipped with the inertial navigation systems that are completely independent of any external system. You know, the stuff they used before GPS.
Herbie J.
You overestimate the difficulty. You do not need a powerful radio or big antennae, because any aircraft that you care about will be trivially reachable with low power (due to line-of-sight). The amount of computing power is, by today's standards, also small. Since you mostly care about signals from aircraft close to you, radio interference is likewise not a big problem, especially with modern (but cheap) techniques.
If you look at the incredible sophistication of modern cellular phones, and the low costs, you realize that powerful, sophisticated and flexible radio systems can be made at very low cost.
The only good weather is bad weather.
www.caasd.org
Specifically, this is Safe Flight 21, which is a MITRE CAASD project.
to accept the praise of personal wisdom is an affront to the very ideal i hold dear.
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.
The only good weather is bad weather.
Do not equate the cheap civilian handheld GPS sets with the military grade equipment.
The transponder replies to interrogation by secondary radar. Not all transponders are capable
:>
of mode-C (Altitude encoding) operation.
Many aircraft don't even have transponders.
Quite a few don't even have radios.
Without a transponder, capable of mode-C, unless
in PAR (Precision Approach Radar, available only
in some airspace environments, and only on the
approach environment (And almost always in
airspace you wouldn't be without mode-C anyway))
coverage, your altitude won't show up at all. And
altitude reported is not allowed to be relied on
by ATC. ATC must maintain lateral seperation. They
cannot stack returns. If returns touched, they
would be in some serious trouble. And piles of
paperwork.
-Kysh
--=:: Wings and tail and snout and scales of blackest night
I am a controller in Canada. I've read a lot of complete BS in the threads below. I'll correct a few statements in point form:
1)ATC can and does rely on the pilot's reported altitude. If the reported altitudes are far enough apart I can stack aircraft on top of each other without ANY lateral separation.
2) GPS does report altitude, but not in a form useful to ATC. At some point it may become possible to separate aircraft based on their GPS altitude, but only if both aircraft are using equipment certified to a common standard. Given the number of aircraft using the older technology, it is unlikely to expect serious use of GPS vertical separation anywhere other than on the ocean (where navigation and altimetry minimum standards are already strictly regulated).
3) Two radar sites could be used to establish altitude in theory however in practise the azimuth/range errors are still too large to make the resulting triangulation anything but a guess. The only reliable way to determine altitude is with a PAR (aka QUAD) radar in which one of the dishes scans up/down to determine elevation/range instead of the normal azimuth/range.
4) GPS position reporting is currently being tested in the North Atlantic oceanic airspace. The aircraft combine the GPS lateral information and altimeter vertical information and send it to ATC via satellite. The system is called ADSR-- "Active-Dependant Surveillance Reporting". The short-term goal is to reduce or eliminate the use of HF radio. The long term goal is to equip enough aircraft to make it possible to reduce the separation standards from 10 minutes (~100NM) in trail and 60NM lateral to only 15x15NM.
5) SSR transponders are a valid component of RADAR. The acronym "RAdio Detection And Ranging" does not neccessarily imply that "skin paint" reflections are required. Radio is radio. Meanings change.
6) There is a form of TCAS-based situation display being tested in Toronto and Calgary. It uses several ground-based TCAS interrogators to produce a 3-D model of the traffic. As with ISSR radar, "non-participating" aircraft would be invisible. "Multilateration" (as it is currently known) would allow us to see into places hidden from normal radar sites and would increase reliability through redundancy.
7) If the pilot sets the altimeter setting incorrectly, the error in reported altitude is 10 feet per 0.01 inches of mercury, or 1000 feet per inch of mercury.
8) Aircraft altimeters report altitude based on a 29.92"Hg setting regardless of what the pilot sets/sees on his display. A pilot cannot therefore "cheat" on his clearance by inputting a false altimeter setting.
I would be happy to answer any specific questions people have about ATC in Canada.
Err..reducing Selective Availability (SA) from GPS/NavStar's Standard Positioning Service (SPS), which is what us non-military types get, does not remove encryption from the system. The Military uses the Precise Positioning Service (PPS), which requires special crypto-enabled receivers and which has its own specs WRT accuracy, reliability, etc.
We-un's don't get to play with that.
Suggest taking a look at the USCG GPS home page (http://www.navcen.uscg.mil/gps/default.htm), or the GPS signal spec (http://www.navcen.uscg.mil/pubs/gps/sigspec/defau lt.htm) for more information (than you want!) Specifically, the annexes contain specs for reliability and accuracy.
Removal of SA simply removed the Control Segment errors deliberately introduced by the GPS NavStart control station in Colorado Springs, bringing the accuracy down to ~22m horizontally. Some yo-yo in Colorado Springs can still, either accidently or on purpose, inject a control segment error of any size in the system: that is by design.
Also, don't forget that GPS accuracy varies directly with latitude -- important for airplanes travelling over the pole or close to it on the way to Europe.
N. --
This is not a "new" idea. The Federal Aviation Administrationn (FAA) has been experimenting with various forms of GPS navigation in lieu of radar for years. However, Radar-based Air Traffic Control has advantages that no GPS can offer.
.05% if it means the cost to consumers equates to a Las Vegas to Los Angeles fare of $20,000.00?) but the potential for savings should be secondary to fundamental questions of safety and reliability.
Before proceeding it might help to explain the basic structure of the United State's Air Traffic Control (ATC) system. Afterwards, a bit of analysis/comments.
Air Traffic Control is divided into two seperate entities : Terminal and En-Route. Terminal facilities control traffic in the immediate vicinity of an airport. En-Route facilities control traffic across country and national borders. Both facilities interface with one another at the points which their "airspace" intersects. In other words, an aircraft departing Dulles International for Chicago-OHare initially communicates with the Terminal facility at Dulles. The Controllers at Dulles direct his takeoff and then "Hands Off" the aircraft to an En-Route facility. En-Route facilities then monitor that aircarft untill it approaches it's destination. The En-Route facility then "Hands Off" the aircraft to the Terminal facility at "Chicago-OHare", and the OHare Controllers guide the approach into the runway. (For the experts: I've ignored Super Tracon's for the sake of simplicity).
Each environment, Terminal and En-Route, uses different types of radar. Terminal environments use radar capable of detecting aircraft within a 60 nautical mile (NMI) radius from the radar site (usually the airport). En-Route radars detect aircraft within a 200 or 250 NMI radius (depending upon the site). Whatever the radar type, it's important (when considering GPS) to note that the cost of radar is tremendous: Initial cost is great, and the cost of replacement parts and staffing of qualified maintenance personel is substantial.
A detail of the FAA Terminal environment: Radar is only used to guide the aircraft to the approach path. Other equipment, known as Instrument Landing Systems (ILS) is then used by the pilot, independantly of the Air Traffic Controller, to land it.
A few details about the arrangement and usage of En-Route airspace. Jetliners don't fly randomly, as the crow flies, across country. Commercial airspace is arranged into corridors of travel and levels of altitude. Using the example above, an pilot doesn't depart Dulles, point the nose to OHare, and head on untill he spots Sear's Tower. Instead, that aircraft has to navigate air highways to reach OHare, just as a car would if travelling from DC to Chicago. And, just as cars travelling in opposite directions use different lanes of a highway, aircraft travelling across country in a particular corridor, going in opposite directions, use different altitudes. The corridors and altitudes have been mapped out by the FAA and a commercial aircrafts flight plan, created before departure, specifies the route which the flight will take.
En-Route radars aren't, of course, placed randomly. There are many En-Route radars spread throughout the United States, and the matrix is arranged such that each bit of national airspace is covered by at least one radar, and many corridors are covered by two, or even three radars. That's particularly true of the most widely travelled air-lanes.
En-Route radar data is sent to En-Route control centers. Computers analyze each radar's data in three square mile segments and, where coverage overlaps, the highest quality data is used. In other words, the En-Route Controller uses the best data available to control traffic.
It's important to note that the safety record of the Air Traffic Control systems, Radar, ILS, or any of the other system maintained by the FAA, is superlative. NO loss of life (and, I'm almost certain, no aviatiion accident at all) has ever been caused by a failure of an FAA mechanical or electronic system. That's not to say that no FAA system has ever failed. However, the system is designed such that any single failure is virtually incapable of bringing ATC capability to it's knees.
I've attempted, in the description above, to give the reader some small idea of the vastness and complexity of the United State's ATC system. I've merely explained the 'bare-bones' of a few aspects of the systems. It would require volumes to explain all of it's nuances.
To wrap-up, there are essentially 2 different environments (Terminal and En-Route), and within one environment, Terminal, there are two functions (approach control and landing) whose current equipment can/might/will be replaced/augmented by GPS. Apparently, from what I read at the ADS-B site, their product is designed to replace both Terminal and En-Route radars as well as ASDE, and ATCBIs (won't get into them due to time limitations) and, possibly, ILS.
Some form of GPS has been experimented with in the Terminal environment: Several years ago GPS landings were tried at Seattle-Tacoma but, as I recall, for various reasons were found to be inadequate, at least not advantageous enough to warrant use of GPS over current technologies.
At about the same time it was widely rumored that GPS-based systems were poised to replace En-Route environment radars. This, of course, didn't materialize. However, at that point I was convinced that, eventually, GPS capabilities would be refined and expanded suffciently to replace some, if not all, Radars in the Air Traffic Control system.
Advantages of Radar:
1. Radar based ATC has a proven, decades long track record of reliability and safety.
When considering FAA GPS implementation It's important to understand that the current system is dependant upon information provided by hundreds of radars. Furthermore, the system as it's configured now has proven extremley reliable and safe. As such, fundamental changes, such as the replacement of radar by ADS-B are, IMHO, viewed with caution by ATC planners. Of course, ATC planners are aware of the potential benefits of new technologies such as ADS-B, but they must weigh the advantages of those technologies against the potential for decreased Air Traffic safety and, therefore, the increased likelihood of loss of human life.
A response to this might be "But that's the point of ADS-B: to increase the margin of safety!" However, the current system is KNOWN to be safe and, while the proposed system claims to provide more safety, it's an UNKNOWN and, as such, is worrisome. I've been a SlashDotter long enough to know that this crowd relishes many forms of change and is certainly prone to welcome new technologies, so this arguement may be anathema to many in the audience. Keep in mind that those making the decisions aren't always Techie types. Those folks making the decisions have to weigh the safety of consumers with the demands of the airline industry and the flying public, amid the often politically motivated pressures of the politicians that appoint and monitor them and the enticing promises of companies like those promoting ADS-B. Despite all of that, I'm confident that the right decisions willl be made and the FAA will eventually implement some form of GPS replacement of most, if not all ATC radar. But I don't expect to see it in the first half of this decade, and possibly not untill the next decade.
2. Radar independantly detects aircraft .
In other words, using radar the Air Traffic Control system can locate and control aircraft independant of ANY piece of equipment (other than radios) on board the aircraft. This is not the case with GPS. Radar certainly has an advantage for purposes of drug traffic interdiction and strategic issues, as trafficers and potential unfreindlies will disable any equipped GPS.
Of course, the likelihood of enemy incursion into our airspace at normal detection altitudes, in aircraft capable of being detected by ATC radar, is extremely minimal. However, the FAA ATC En-Route radar system is the ONLY radar system that monitors every inch of airspace in the country. The military has none (at least none they admit to) However, the coastal and border En-Route radars provide a data feed to military command centers, and that data is used to monitor potential threats.
3. Radar detects weather.
ATC radars, both Terminal and En-Route, not only detect aircraft. They are also used to detect inclement weather, and the data is used by Controllers to route aircraft around potentially hazardous areas. GPS doesn't meet this need.
A counter argument might mention the existence of the National Weather Service's NEXRAD weather radars across the country, systems that might be used more effectively for the same purposes, as well as Terminal Doppler Weather Radars located at many high volume airports.. Unfortunately, I'm not an expert on the range of coverage of NEXRADs, but I doubt that it's as extensive as En-Route radar's
Advantages of GPS:
1. Cost.
Inital implementation might be expensive, but compared to radar, I would guess that ongoing expenses would be greatly reduced.
My first thought is that, of course, it's nice to save money but let's not allow the holy grail of reduced cost to drive the debate. Ultimately, when considering risk the cost of a human life must enter the equation (do we really want to increase the safety factor by
2. Improved accuracy.
While improved accuracy is an admirable goal, I'm not sure of it's value. If accuracy currently provided by radar is adequate, and as far as I know it is, then why is improved resolution an advantage? Ultimately, the question of resolution must be based upon the issue of aircraft velocity and congestion.
Old En-Route radars have, at worst, 1/2 mile range resolution and the seperation between the commercial aircraft within traffic corridors is much, much greater than that.
There's also the question of the ASDE but, as in the case of the other radars, it's accuracy out of the box is designed to meet the requiremnts of it's task.
3. Simplification.
This appears to be one the greatest potential benefits of ADS-B. Many different types of systems could be replaced with a single system, Terminal and En-Route radars, ASDE, ATCBIs (another one I don't have time to describe), and possibly ILS's other NavAids equipment. Sounds like some On-Board systems could be simplified as well. For instance, the On-Board ILS and the collision detection equipment are now seperate systems. However, it appears that, with ADS-B, these two systems would, essentially, be the same, or at least use the same source of information.
There are other advantages, but time doesn't permit me to continue. Hopefully this will provide those interested with a bit of information.
A few comments regarding the claims of the manufacturer of ADS, found at the link provided in the article:
"And, since the equipment is so small and light, it can be made a standard part of the equipment on board an aircraft, allowing pilots to see an accurate depiction of real-time air traffic, along with controllers."
The current Air Traffic Control system is based on Air Traffic Control system analyzing air traffic and, based upon that analysis, communicating directions to the pilot of an aircraft. The advantage of that arrangement: the pilot is completly free to focus on controlling and monitoring his plane. He doesn't have to divide his time between caculating the best approach into, or monitoring the airspace of, say, a large airport during peak usage times all the while navigating his aircraft into position. I want the aircrew on my flight to pay attention to NOTHING but the aircraft while landing, and I want an Air Traffic System that will allow them to do that. ATC completly removes the burden of approach control and airspace monitoring out of the cockpit and allows the crew to worry about nothing other than the aircraft during a very critical time.
Obviously, ADS-B would be very useful as an on-board tool for monitoring nearby traffic and alerting pilots to potential collisions. There are, of course, devices in use today that perform this funcion, but I'm not qualified to judge their capabilities as compared to ADS-B.
"And it is effective in remote areas or in mountainous terrain where there is no radar coverage, or where radar coverage is limited."
Marketing hype, misleading at best.
Next time you fly into Salt Lake City keep an eye out for a large dome on top of the mountains just to the north of the City. That's an En-Route radar. That radar's not perched up there so the guys at the site can have a nice view. It's located there to optimize the radar's coverage of mountainous terrain. There are many such radars in the mountains of the western United States. As I've said there is NO portion of the CoNUS that is not covered by radar and many, if not most are covered by two and even three radars. Of course, these radars aren't desinged or located to detect A10s cruising at 100' above the floor of a mountain canyon. Obviously, there aren't many Jetliners down at that altitude. They stick to the airlanes I've described above.
And, from the article:
"aircraft are no longer dependant upon crypic orders from the gound to understand where everyone else in the sky is"
Cryptic orders from the ground providing the positional information of other aircraft? One of the purposes of the ATC system is to remove the burden of airspace monitoring from the pilots. Controllers monitors airspace, and route aircraft accordingly. Controllers don't communicate the location of every aircraft in the immediate vicintiy to every pilot in the vicintiy and let them take their chances. They provide, among other things, heading and altitude commands to the pilot and he directs the aircraft accordingly.
As for "cryptic orders", I suppose the ATC lingo might be considered cryptic to some, but certainly no more so than a lot of the discussions that take place on Slashdot regarding network protocols, UNIX, or any number of topics. ATC language is merely a strict language designed to communicate required informatiion in a standardized manner. Perhaps the biggest "ATC Lingo" issue is the fact that it's based soley on english. I believe there was a deadly aviation accident in India some years ago that was rooted to the fact that english wan't the first language of the pilots or controllers. Technologies are being developed to remove the potential for misunderstanding: In future, Pilots might hear, or read on a display screen, in their native language, the Controllers instructions, regardless of the Controllers native language.
Two final footnotes.
1. SlashDotters may be pleased (and, if you're a frequent flier, relieved) to hear that Unix-based workstations are at the core of several new FAA systems, including, most prominently, the ASR-11, a Terminal environment radar. The ASR-11 as at it's core two Ultra Sparc 5s. Furthermore, communication between primary components within the radar and between the radar and the Tracon (the building/s that houses the Controllers and all of the equipment they use to control aircarft) is via Ethernet. I've just bought Spurgeon's "Ehternet: The Definitive Guide" in order to study up on the subect (I'll be maintaining an ASR-11 beginning sometime next year.
Other Sparc Station-based systems: Terminal Doppler Weather Radar and the ASR-9's WSP.
The use of networks and Unix is becoming so prevalent that both a Unix and a Networking course are taught by the FAA at it's Oklahoma City training center and are requirements for some (many, all?) of it's radar courses.
2. Now, for a pet peeve: the absolute ignorance, if not sheer stupidity, of mass media when reporting FAA issues. I'm a PBS NewsHour afficianado, and anyone familar with the NewsHour knows that excellent panel debates are one of the best features of the program. However, I've seen some so-called media aviation experts on the NewsHour that couldn't tell sh$^ from shinola, but acted as though they were the burning bush. Furthermore, another media source that I usually have great respect for, the New York Times has, in recent years, featured some FAA ATC articles that completely missed the mark.
The reason? In my opinion it has to do with the vast complexity of the FAA ATC system that I've described in very limited detail above. No one not intimately familar with the system, over a period of years, could possibly comment on it intelligently. Keep that in mind the next time you hear some talking head lambasting the FAA ATC system. For that matter, keep it in mind the next time you see some idiot politician hold up an old vacuum tube and use it as proof that the FAA ATC system is outdated and unreliable (for those of you that don't recall, that was Al Gore)
One thing all aircraft have in common is that they must land at some point. If this point allows only 60 airplanes to land during a 1 hour period and 100 show up, what happens to the extra 40? To think that GPS can reduce this type of congestion is simplistic thinking. The only solution is increasing the aiport landing rate. How do we do this? You build more runways and airports. So lets put a new runway at LGA. Not so easy when you get down to it. Politics, bulidings, taking land, filling in wetlands, noise abatement concerns, money, and on and on we go. To put this example into terms that a Linux geek can understand is this: how can you improve your internet connection speed when you are using 14.4 relic modem? A new 1.33 ghz won't help much, a larger hardrive might help a little (increased caching space), more RAM--naah, even swithing to Red Hat 7.0 won't solve the problem. You need to eliminate the bottleneck at the 14.4 connection. A T1 would do the trick. We simply can't build new runways and airports as we can get a T1 connection. So the current airspace problems will go unsolved with any new hardware/software solution. The airlines want all their flights to land at the same time so their clients will make connections onto "their" airplanes, not a competitor. It is called the "hub and spoke concept". Go to CLT and notice how many US Air airplanes you see, and how few United Airline airplanes there are, "hub and spoke" in action. You must put a carbon monoxide detector in your house if you really think that "with an autonomous system, without human controllers, such fixed points ... would be unnecessary". You forgot the Mang Bang mesobrain, the one fixed point that all aircraft must come to, the landing airport. Refer back to my first sentence. It is really not that complex of a concept to grasp.
As a current military trained commercial pilot, and a current Air Traffic Controller who has been "pushing tin" for over 19 years (it pays for my Linux habit), the thing that I find that sucks about the current system are small brained former pilots who think they have the big picture. Worse, small brain former pilots who make ignorant statements to non-aviation specilists just to satisfy their egos. Issuing a Private pilot liscense to some people is sort of like throwing a pack of matches into a monkey's cage, the results become, well umm, rather heated.
ps. hey mesobrain, what happened to those 40 aircraft that couldn't land?
mbyrne
This strikes me as a really bad idea. The problem is that, in any system as complex as an airplane, it is diificult enough to keep track of local airspace, much less the "big picture". What happens when an air traffic controller tells a pilot to do something, and the pilot disagrees based on what he believes to be "superior information". Perhaps keeping the pilots a little in the dark makes it a lot easier to make sure they are where they need to be. for some things, centralized control works better.
Actually, the aircraft I work on do us inertial navigation systems. And while they are expensive as all hell; I've only had to replace 2, right as the warranty expired.
I would assume that in the future you will see most aircraft with Inertial Navigation systems, making the ADS-B system even more percise. Untill then, a GPS system with an error of 5 meters, or possibly even 50 meters (How big is that plane anyways?) would work just fine.
--Cam
All jocks think about is sports. All nerds think about is sex.
I saw a crappy movie once where they had anti-satellite-missiles mounted on aircrafts. And I guess shooting down satellites can't be all that hard, since you know their trajectories quite well. Especially with the GPS satellites ... and you can also home in on their signal. And since they can't run away, you have plenty of time to do it.
...), even though I guess that would be pretty well known.
So I guess that would really be a possible strike that Iraq could (at least in theory) do against the US. And the US would have a hard time guiding their weapons against the source of the attack (if successful, that is
EagerEyes.org: Visualization and Visual Communication
Consider that there are *many* places on the planet that do not have radar coverage, the Pacific Ocean being a good example, many parts of Africa another. As a pilot, I can tell you that controllers make mistakes, usually because their 30 year old computers don't give them enough help. Nothing beats looking out the window but if it prevents just one mid-air, it's worth it!
Yes indeedy, folks. THE UPS has 245 aircraft, literally an airline unto itself. As for the tracking (which I work on, BTW), I challenge you to a) compare it with Fedex or USPS; b) tell us how to make it better.
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.
I beg to differ. The current ILS systems need sub-meter accuracy so that the planes can properly measure how well they are holding to the glide slope. (You know the rule: your tools should be ten times better than your real need.) By using the DGPS there, and using regular GPS away from airports, you get the best of both worlds.
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!
The only good weather is bad weather.
O'hare is trying to use a similar system (or the same?) to pack in more landings. with the improved accuracy they can "safely" route them closer together.
Why, in Diehard II, didn't someone walk out to any of the hundred or so planes on the ground and get on one of their radios? Or use one of their aircraft-band hand-helds or mobile radios in the offical airport SUVs? Incredibly weak plot-point, especially since the first two Die Hard movies made use of magical radios that can talk to anyone else with a radio.
Everyone seems to be under the misconception that the current radar system does not rely on airplanes to report any status. In fact, each airplane in the "system" must have a transponder, which responds to the querying groundstation (providing response-time derived range and bearing) with a 4-digit octal code (providing identification, also used to communicate emergency info) and altitude. Without this properly responding transponder, the airplane is most likely invisible. Also, examine current TCAS collision avoidance systems.
Ecce potestas casei!
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.
Regular GPS, even now that the selective availability has been turned off, is far less accurate in altitude than in lat/long - it is a simple matter of geometry. My consumer GPS is rarely more than 15 feet off in location now that SA is off, but altitude varies by a lot more than 100 feet. So DGPS (which was not, contrary to what one poster seems to imagine, invented by some Swedish guy who is being locked out of US markets) is still important if you care about your altitude - i.e. when anywhere other than en-route.
For those who keep mentioning altimeters, they should realize that altimeters depend on ground supplied correction factors ("altimeter settings") for their accuracy, and aren't all that accurate anyway. An altimeter is just a barometer with a different readout - which should tell you that weather changes cause apparent altitude changes. This has been responsible for many crashes over the years. Here in Arizona, where ground reporting stations are far apart and tall mountains are frequent, knowing altitude more accurately would save lives among those who, through follishness or occasional bad luck, tempt the aviation gods in bad weather or visiblity and fly too low.
The only good weather is bad weather.
----
what if a GPS sat. was to go out of service? couldn't this have nasty effects? also with everything lately relying on GPS navigation what if say some group of terrorists, rogue country, or whatnot were to take out key satellites, leaving us fucked
Two wrongs don't make a right, three lefts do!
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..
Ahhhh! Gnutella for Gnavigation!
"I will gladly pay you today, sir, and eat up
Sacred cows make the best burgers.
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
Anything I post is strictly my own thoughts and doesn't necessarily have anything to do with the opinions of IBM.
there is a honking big solar flare occurring now. see BBC article for details.
"..don't you eat that yellow snow."
When the US govt turned off the "fuzzification" on GPS, increasing its accuracy, there was an interesting thread of discussion on usenet sci.crypt about the plausibility of someone faking the GPS signal, and misdirecting aircraft. (look on deja or something) IIRC there is no real secure verification of the signal, which could cause problems...
Ploughing through yachts on SF harbour due to GPS errors.
Who needs pilots eh? I have spoken to people at Aus's CAA who prefer that planes be controlled from the ground rather than by those pilot thingies.
Slashdot: Where nerds gather to pool their ignorance
What I haven't heard anybody say yet is this isn't just a question of competing technologies; it's a question of who's in control. The airlines and their pilots look at the mess the FAA has made of ATC in this country and imagine NOT that they could do better (which is possible, but it's not as easy a thing to do as it might appear), but that they can find a way to get by without 'interference' from ground-based control operations entirely. I've already heard it said that UPS's system could be expanded to 'reduce reliance' on ATC--it's the whole reason the display is intended for pilots, and not controllers. Pilots and airline managers see a big, open sky, arbitrarily made small and congested by the imposition of 'airways' and 'Standard Terminal Arrival Routes' and 'Standard Instrument Departures', and conclude that without these FAA-created artifacts, modern technology would allow aircraft to depart, fly directly to their destination, and land with no hassles from Big Brother. What a laugh. Ever been in a parking lot when everybody decided to ignore the white lines on the pavement and drive straight toward the exits? This is not an oversimplification. Hartsfield Int'l in Atlanta has never done better than land 120 aircraft in an hour, and that was years ago, before they had so many heavy jets and before B757's started getting extra spacing for wake turbulence. On a cloudy day, landing 80 in an hour is something to cheer about. Despite this, the airlines routinely schedule 110+ arrivals in an hour. Sometimes over 35 in a quarter-hour. Without controllers to decide who lands and in what order, it's a parking-lot-funnel, at jetspeed, and with no brakes. From 360 degrees of the compass. Giving pilots a picture of the airspace around them and the aircraft in it is an excellent idea, both as a back-up against ATC failure (it happens), and as a way to keep controllers (who do after all work for the government) honest. But it won't be getting the FAA out of anybody's hair anytime soon.
Actually by my experience FedEx so far was faster with tracking. Though the last time I shipped (or got shipped) anything with either of them is over a year ago.
If you want to e-mail me, use my PGP Key.
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.
The only good weather is bad weather.
Civilian aircraft in the US are NOT required to carry transponders, except when in controlled airspace.
The only good weather is bad weather.
I don't see anything new in this. It is basically just a modified APRS setup designed to fit in airplanes, and to be approved by the FAA. Technically, it would be very easy to implement. It could just use standard packet radio operating on aircraft frequencies.
The only realistic way that someone could try to crack the system would be to report an additional plane, or to be actually on a plane and crack the hardware to make it report the wrong position. The system probably wouldn't be used to replace the current system, but to make it more accurate. GPS data at altitude should be very accurate. Most of the inaccuracy of the GPS system is caused by the atmosphere. A mile or two up there is a whole lot less atmosphere to worry about.
Now, what we really need is for the standard ELT's (Emergency Locator Transmitter, one of the black boxes, it is a beacon that goes of when a plane crashes) to include a GPS receiver with a transmitter to report the location of the accident.
GPS is not only difficult to spoof, but is hard to block. It is a spread-spectrum technology, and that means blocking it either requires inordinately high power, or transmitting a correlated signal. The latter is just as difficult as transmitting a spoofing (intentionally erroneous) signal.
The only good weather is bad weather.
Iraq has anti-aircraft missiles of the same type Cuba used to shoot down Gary Powers in his U-2.
g atorServlet.pl?docNumber=12389&partNumbe r=1&method=generateFrameSet&totalNumber=1 )
[pedantic mode=ON]
Mr. Powers was flying over Russia when he was shot down by a Russian V-75 missle. No Cubans were involved. ( http://www.foia.ucia.gov/scripts/cgiservlets/Navi
[pedantic mode=OFF]
err... Russia shot down Gary Powers, not Cuba!
The only good weather is bad weather.
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
Sounds like a very large scale implementation of APRS that hams have been using for a while! pretty damned cool!
The replacement for ELT's, called EPIRBs, operate on a higher frequency (406 vs 121.5/243) MHz with higher accuracy. They can be located much more accurately, so they don't really need the GPS (although some of them have it).
I have done many ELT hunts for the Civil Air Patrol. The problem with them is not the lack of GPS, but the lack of quality. According to NASA statistics, 97% of ELT activations are false alarms, and in 50% of real crashes, the ELT's fail to operate.
This great (%$%$%$@@) system was brought to you by the FAA - the same people who operate the air traffic control system that the GPS system could replace!
The only good weather is bad weather.
ATC does not have altitude determining (height-finding) radars. It relies solely on the on-board altimeters of the aircraft.
The only good weather is bad weather.
Removing the Dither from GPS has certainly increased its accuracy without encryption but has opened the door to subversion of the system. Since the signal is not encrypted anyone could produce a false signal. Either they could make an aircraft think they were somewhere they were not or spam the airport with false aircraft transmissions. Who needs a stinger when you can drop aircraft just by cracking the system?
But isn't this a bit of a security problem? It should take the bad guys (and the "good guys", for that matter) about ten seconds to put together a missle that uses your broadcast info to figure out where you're going and do a perfect intercept, every time.
We use a decent system for tracking planes for "planning purposes". The data stream is not sent back to pilots but its used for calculating arrival times for support planning on the ground and for noise abatement. Its a passive system that works with the FAA's radar located at airports. A dimensional array antenna reads the planes IFF responses triggered from the airports radar. The plane responds back with its actual altitude and tail number, the array knows the relative angle of the airports radar to calculate the angle and uses the return pulse time to calculate distance. This is all processed with a RedHat box with some realtime kernel patches. The output is sent to a central unit (probably a mainframe but could be anything I guess) and merged with data from other airports and operational schedules. In our case the overall output is sent to nice looking display on HPU boxs. I actually got to see the systems replay of flight 808 going down of the coast of Long Island. A system at ISP (Islip?) airport was tracking that area at the time.
Bad boys rape our young girls but Violet gives willingly.
This is an aviation system. Any mode c transponder sends altitude info air traffic control. It is no problem to add this info to gps data to other A/C.
railroad maps, or any thing wich cannot be interrupted by a third party or the Government in cace of war. Such as INS which has been better than a meter quarter way round the world since '67.
TACAN air to air has existed since at least the Viet Nam war. This is basically giving position of one airplane in relation to another,using radar. encoding the echo. altidude no problem. GPS just provides reference of lat and long and all AC provide the altitude untill they crash and burn.
As others say, GPS can do X, Y and Z when there are enough sats visible. However, this isn't really accurate enough.
Alternatives are DGPS with a ground-base correction or to have an altimeter based correction.
As someone who uses GPS on a daily basis, I can tell you the system is far from perfect, and IMO, the biggest problem with GPS today is inaccurate positioning data generated by corruption of the GPS signals, this in part being due to the crazy atmospheric conditions we are currently experiencing from this rather active solar cycle. Until things settle down, we've mandated all of our critical GPS control work be performed at night; while not a sure guarantee of a quiet atmosphere, the quality of the data gathered during nighttime hours seems to be much "cleaner".
Land surveyors around the world have been making good use of GPS for about the past 10 years, in areas of open terrain and for large topographic surveys that have good "sky", it's unthinkable to not use it. I depend on it daily to "get the job done".
Here's a link to some interesting GPS information for those of you who might not realize how important GPS has become to the world of civil engineering/land surveying:
http://www.ngs.noaa.gov/CORS/cors-data.html
I hope that this would be used as an auxillary or backup system to the standard radars and air traffic controllers.
This is not strictly true. GPS will report the receiver's *spheroidal* altitude (ie, height above the theoretical figure of the earth it used to calculate your latitude and longitude), while the aircraft's altimeter will report *geoidal* altitude (ie, height above sea level) and these are usually significantly different. Add to this the complications of GPS giving height in meters and aircraft instruments giving height in feet, and the possibility that some people will be using a spheroid other than WGS84 (thereby being somewhere other than where they think they are), and you have the makings of a mars lander sized disaster, only involving real live people.
What a long, strange trip it's been.
First off. RADAR WILL NOT BE RETIRED. If theres one thing extremely important in aviation, its redundancy. I'm talking multiple, anal retentive type redundancy. For an aircraft to even be able to fly into the clouds, you have to have two VORs (a type of vector-based radio navigation, flying radials off of VOR stations). You cannot go out of radar coverage in the United States for more than 65 miles- not per regulation, but thats how good the coverage is. Plus, theres the ADF, which works off of radio towers and just kinda points towards the towers. And LORAN. And plain old pilotage. If you are truly have good situational awareness, something can fail and you can keep flying without going into a mountain.
The entire aviation industry seems kind of backwards in ways, for one reason- safety. They are among the last to adopt new technologies. Take, for instance, the E6-B. It's basically a slide rule for pilots. They've been using it for years and years. They still require you to know how to use it, even if you have a digital flight computer.
In addition, GPS approaches have been used for some time now. Its a non-precision instrument approach, since it doesn't give you information based on your glideslope. It's pretty damn reliable, but most airports have more approaches than just the GPS approach, so if you are in instrument weather and can't see to the ground, you can request another type. If you are so lost that you don't know where you are at all, something is very wrong.
So, onward to the point. This may be a great technology, but it will be introduced slowly, if it is found to be unreliable, it will be scrapped. It sounds like a great navaid. The pilot will still be in communication with the air traffic controller, though, and still has the other instruments (including the compass- pretty hard to spoof that one) that they have flew on for so many years.
What do I do, when it seems I relate to Judas more than You?
Still not dead.
All of the posts I've seen in this article seem to express concern for the possibility that Someone Evil (tm) will spoof, jam, crack, overload, or otherwise muck with the system, in order to (presumably) cause a collision.
I submit that the real danger is not necessarily from these sorts of attacks, but from the aggressive financial goals of the airlines themselves.
The article says that each aircraft will (theoretically) have a view of the airspace, and will no longer be reliant upon the cryptic instructions of ATC. However, with no (relatively) impartial authority in control of the situation, *pilots* will become the ones who decide what routes they will take, and, further, whether they have a safe margin for error between their aircraft and another. And commercial pilots work for....big companies. And big companies want....increased profit margins.
How many of you out there have recommended a particular piece of kit, or a particular bit of software, or a particular process to be followed, to minimize risk, and have the corporate beancounters, who know nothing of the practical considerations other than that your proposal has a higher short-term cost than *their* proposed solution, the one that comes from BillyBob's Bait Shack and IT Services Company.
Air Traffic Controllers have the advantage of not having a corporate bottom line to meet, and their decisions will therefore not be coloured by short-term financial gains...
I *invented* pants!
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.
Software Engineer & Writer of Military Science Fiction and Fantasy Blog: petermwright.com Twitter: WrightPeterM
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.
"Ancillary does not mean you get to rule the world." --U.S. Circuit Judge Harry Edwards, speaking to the FCC's lawyer
Wow, rely on the airplanes to report their positions. Wouldn't it be fun for a trouble maker (or another country) to broadcast phony positions? Geeze, there weren't 500 planes in my airspace a minute ago. Maybe they'll have to sign the data (shouldn't be too hard to keep everyone's public key :).