I read about an air traffic control system changing from radar to GPS. But wouldn’t you need both ? Wouldn’t ?
you first need to build a system that used radar and GPS ? Only then could you be confident about omitting the radar bit.
no way. GPS cannot replace radar for ATC.
GPS can be disabled, satellites that the GPS system rely on can be knocked out by natural occurrences, weapons, EMP shockwaves created by nukes, etc etc.
GPS in the ARTCC or Center can only tell ATC where they are. The planes need their own GPS and that data needs to be transmitted to the ATC on the ground. There are way too many ways that the GPS system on the plane or the data link/transfer could fail. It’s just not safe nor responsible to replace ground based radar with GPS data from the planes.
Terrorists would have an easier time too.
by replacing ground ATC radar with GPS, you’re essentially taking an institution that controls thousands of planes and turning it completely passive. It will no longer be able to actively detect anything. Present day radar use transponder but when these are turned off on the planes, the radar can still detect, albeit faintly, the radar wave reflection off the aircraft.
GPS may supplement radar for the ATC, that for sure. But never replace it completely.
It may work one day if a transponder style GPS link activated by radar or some other sort of thing constantly sends data on demand from the airplane whenever the activating signal is sent. It better be hidden really deep inside the plane. Then again, there’s a chance that terrorists could remove some other vital piece of the GPS receiver. Mechanical failure would still remain catastrophic too. Radar will stay in the ATC’s arsenal as a primary means of detecting aircraft. I’d rather invest in research and development of a more reliable and sensitive system similar to radar like Ladar rather than try to improve GPS up to a point when it’ll be "fail-safe"
no way. GPS cannot replace radar for ATC.
GPS can be disabled, satellites that the GPS system rely on can be knocked out by natural occurrences, weapons, EMP shockwaves created by nukes, etc etc.
GPS in the ARTCC or Center can only tell ATC where they are. The planes need their own GPS and that data needs to be transmitted to the ATC on the ground. There are way too many ways that the GPS system on the plane or the data link/transfer could fail. It’s just not safe nor responsible to replace ground based radar with GPS data from the planes.
Terrorists would have an easier time too.
by replacing ground ATC radar with GPS, you’re essentially taking an institution that controls thousands of planes and turning it completely passive. It will no longer be able to actively detect anything. Present day radar use transponder but when these are turned off on the planes, the radar can still detect, albeit faintly, the radar wave reflection off the aircraft.
GPS may supplement radar for the ATC, that for sure. But never replace it completely.
It may work one day if a transponder style GPS link activated by radar or some other sort of thing constantly sends data on demand from the airplane whenever the activating signal is sent. It better be hidden really deep inside the plane. Then again, there’s a chance that terrorists could remove some other vital piece of the GPS receiver. Mechanical failure would still remain catastrophic too. Radar will stay in the ATC’s arsenal as a primary means of detecting aircraft. I’d rather invest in research and development of a more reliable and sensitive system similar to radar like Ladar rather than try to improve GPS up to a point when it’ll be "fail-safe"
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Contrary to what David has written, the FAA and DOT are working on a system as we type this that will utilize GPS to replace RADAR. RADAR is old technology that has long outlived it’s intended job. The GPS technology is much more reliable and accurate. Albeit in the distant future, RADAR will be replaced.
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Active Air Traffic Controller
You are probably referring to ADS-B. The aircraft’s equipment will electronically and constantly provide its position and identity to ground and satellite receivers to air traffic control. Ground based radar returns and transponder codes will no longer be needed to identify aircraft since the signal encodes the aircraft’s identity and position. Currently primary targets or "skin paint" are seen by radar. If the aircraft is squawking a discrete code the target changes to a digitized beacon symbol. The aircraft must then be paired with its flight plan for the flight in question by starting a computer track. The only flaw is if a flight is assigned a discrete beacon code and the aircraft is not squawking the correct code, the aircraft must be identified utilizing non-radar means. ADS-B eliminates this since the aircraft is always associated with its flight ID for example N123AB is always seen as N123AB, not just beacon code 1234 that is probably N123AB. Many more advantages are possible if the system works.
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en route air traffic controller
additional info here http://www.ads-b.com/home.htm
ADS-B will not ever completely replace the surveillance role of radar. If the system relied completely on a computer compilation of coordinates from GPS equipment on aircraft to build up an image of the aircraft in an area of airspace, all that would be necessary for an aircraft to pass undetected would be for the crew to switch off the GPS. That does not make for very good security, does it? It would even be possible for someone who is up to no good to alter the position marks so that the subject aircraft would appear to be in a different location from its actual location.
Also, it would leave no provision for managing aircraft without electrical systems or with malfunctioning or inoperative equipment.
So there will have to be a continuing RADAR infrastructure. With ADS-B fully implemented, the RADAR does not have to operate at all times, but can just turn on for a few seconds, say, out of each minute. This so-called "winking RADAR" will not only reduce the radio signature of a radar station, making it harder to locate the position of the RADAR, but will save lots of energy and equipment life. It will add data to the image mix, so that aircraft that are not reporting by ADS-B will be noticed and the appropriate action taken.
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retired airline captain
I’ve heard that they are going to update the LORAN systems as a back up to the GPS system.
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RADAR won’t be replace anytime soon. I think you might be referring to the VOR system. There is talk of the VOR system being replaced eventually with GPS systems.
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Radar and GPS serve two different purposes, and neither can replace the other.
Radar is used for surveillance of airspace. It allows aircraft to be located even if the aircraft have no special equipment on board. There will always be a need to watch airspace in this way, so radar isn’t going away.
Hybrid systems of radar and active equipment on board aircraft are in use and will be enhanced. Mode C transponders are a classic example. These systems are extremely useful and help to improve safety, but they allow spoofing with malicious intent, so they cannot be used alone.
GPS is similar. The GPS system uses passive receivers to provide positioning information to a vehicle; it does not provide surveillance. Equipment incorporating GPS can be designed to report positioning information to a third party (just as transponders report altitude), but this again is vulnerable to spoofing, so it works if everyone is honest, but may cause problems if some people are not. Since GPS is passive, there is no way around this problem through GPS alone. GPS also lacks the precision provided by more traditional radio landing aids, such as ILS, and while there are workarounds that involve GPS in combination with other techniques, ILS is likely to remain the gold standard for some time to come.
The current fad of trying to rely more and more on GPS reflects a misguided belief by aviation authorities that GPS is a panacea that can replace everything else at low cost. This isn’t actually true, so other methods of navigation and airspace monitoring will have to stay with us for the foreseeable future, if safety is to be maintained. This means things like surveillance radar, VORs, and even Loran or NDBs, all of which are much more resistant to spoofing.
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