Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS
wsj.com
wsj.com
You could probably cause a lot more trouble by buying an aviation radio off the shelf and just chatting on the frequency or issuing fake clearances if you want to be a mass murderer.
Ultimately the system comes down to many systems working together, not one stream of commands between two computers.
Incidentally, I am happily surprised that that never seems to happen. One could so easily create so much chaos at an airport... There is no authentication whatsoever.
Or are we talking about the boogieman that is an excuse for all sorts of paranoid crackdowns, expenditures, and questionable legislature?
Who exactly are you afraid will sponsor radio jammers at airports, and why do you think they will do so?
Just send the voice data through a raspberry pi to a remote location and carry out the attack from there. You could send voice data through a TOR-like protocol or something to keep you anonymous, if that's important. You could maybe rig some explosives to go off if the FBI/FCC/FAA gain access to the attack point, to prevent them from recovering evidence.
Lot's of police/fire radio systems are similarly without authentication, so you could amplify the mayhem by doing the same thing to those frequencies.
Especially near major metro areas, unintentional interference is a daily issue. These systems immediately triangulate sources of interference in a wide band. Or you have simpler systems like UMS100 that just do alerting and you send out an engineer with a wand to walk around for a bit to triangulate it.
Add some fancy voice synthesis, and it gets interesting. The attacker could clone the voice and style of the air traffic controller. The attacker could provide enough power to quiet out any other transmissions. To keep the air traffic controller incompletely aware, the attacker could provide interference (just to the tower) whenever the victim aircraft begins to transmit.
It actually happened near me once when a local crazy guy got mad that planes were flying near his house (he bought a house right across the street from the municipal airport) so he found an airband radio and started yelling at them every time they came too close for his liking.
He probably got lucky and had a station within 5-10 miles of his bathtub...
The fact that no one has ever truly tried that sort of poisoning of radio calls is more due to the tower and aircraft having a very well defined set of calls, so that the likelihood of false transmissions being able to cause havoc is minimized already.
I agree with another commenter that aviation radio systems should be the simplest, most reliable systems possible, and have that layer of communication depend on proper radio call discipline and no more.
But what about cheap SBCs dropped somewhere with a battery and some custom periphery working as a relay? Of course the SUVs could find that. After the fact.
Problems happen when either (1) technology to do harm becomes commoditized and freely available so less capable people can acquire and use (eg. Easy conversion of semi automatic to automatics, commoditized hacks for script kiddies) or (2) capable people feel they're been sufficiently wronged that they don't care about the consequences of revenge (pretty much all the really big headline terrorist actions)
Most intelligence activity on prevention focuses on (2) since pulling off such actions generally requires the capable planners to coordinate with less capable "feet on the ground" who can give things away. However capable people acting alone which happens occasionally is pretty much impossible to stop (Timothy McVeigh, Ted Kazynski, Kaloyev)
It happens rarely, but pilots are also trained to not blindly follow clearances. They are still pilot in command.
I was flying once with a buddy of mine who was Pilot-In-Command and we lost (or thought we had lost) our radio on an IFR flight back into the Bay Area. What had happened was the Push-to-Talk button on the yoke had become stuck and we were transmitting the entire time while attempting to diagnose what was wrong. This happened for about five minutes. Thankfully he had a handheld radio in his flight bag, and when we turned it on we figured out really quickly what was going on.
In that scenario, if we didn't have the handheld radio, it would have caused a worse problem.
In the worst case, there are non-verbal methods of communication that pilots or ATC can employ (ATC can send light signals, pilots rock their wings to signal communication failures, etc.)
Every airplane between you and your destination, on the other hand, would find themselves being rerouted.
My point was that having the handheld radio allowed us to trouble shoot the situation. Without the radio there would have been a lot higher workload and less of a margin for safety.
https://en.wikipedia.org/wiki/Airband
One of the reasons why airband radio uses amplitude modulation is so that a much more powerful transmitter (ground based, operated by air traffic control or tower personnel, with access to very high Tx powers), can transmit on top of spurious transmissions coming from low powered aircraft or handheld transmitters. The big ground based Tx can step on an interloper and communicate its message to all aircraft on the same frequency.
Article is pay-walled so I didn't read, but the title explicitly says 'from Radar to GPS', ie away from Radar altogether. It doesn't say, GPS to supplement radar.
[0] https://aviation.stackexchange.com/questions/43283/do-todays...
No they don't.
Most secondary (surveillance) radar in the US has been shut down already.
The FAA has been busy shutting down basically anything that requires maintenance, and LORAN is gone too.
I believe the whole point of ADS-B out was to shut down basically the rest.
Source: commercially-rated pilot.
https://en.wikipedia.org/wiki/VHF_omnidirectional_range
(Sorry, paywall is blocking me)
I suspect VORs will be kept for airport locations and en route instructions, but most others will be shut down in favor of GPS.
They've been reducing the number of redundant ground stations lately as part of a project called "Minimum Operational Network", or "MON". (Mostly on affecting the east coast.) But they're explicitly making sure there's enough coverage that you can get a VOR signal anywhere above 5,000 feet AGL.
More info: https://www.faa.gov/about/office_org/headquarters_offices/at...
Given that then ADS-B mandate was just a couple weeks ago, it seems logistically odd that secondary radar would already be turned off.
More generally, my understanding was that the FAA was keeping primary+secondary radar around to augment ADS-B via sensor fusion. I know the "reply" light on my plane's radar transponder still lights up regularly, so at least out here on the west coast the secondary radar is still active. :)
I've also heard there's a longer-term plan to consolidate ATC radar into the NOAA weather radar stations, once they upgrade weather radar to phased-arrays at some unknown point in the future. The marginal cost to keep secondary radar running in that environment is basically zero.
That said, they have certainly been turning down many of the redundant VOR stations as part of MON, and they just turned HIWAS off last week.
I don't think anyone really misses LORAN, though. ;)
I'd like to be wrong about this, but I'm not sure how I am. How am I potentially wrong about this?
It doesn't have to make sense.
From the FAA itself: "The Mode S SLEP Phase 2 program will implement modifications to the Mode S system to sustain secondary surveillance service through 2028."
0 - https://www.faa.gov/air_traffic/publications/cip/files/FY16-...
Maybe you're thinking of old-school SSR radars ?
Lots of issues I'm sure. It'll be interesting to see how this sorts out.
> he’s seen truckers trying to avoid paying highway tolls, employees blocking their bosses from tracking their cars, high school kids using them to fly drones in a restricted area, and even, he believes, undercover police officers using them to avoid tails
These guys were doing it because they were tasked with keeping LTE towers synchronized and they did it with GPS time so they were building in resilience to their time sources by measuring the signal level and rejecting anything that came in too strong. Spotting jammers was a side benefit.
What do you mean by this? You sound pretty knowledgeable, so you must know that it's simply not possible for the GPS signal to have latency or lag.
The signals have to be received from each satellite, then processed to yield a position valid at the time of transmission.
Every GPS fix you get is delayed by AT LEAST that processing time. Any filtering adds more lag.
Most navigation systems look at the T(fix) -> T(now) difference and project your now position from the prior fixes. Especially if you're following driving directions as opposed to free movement, then programs like Maps etc project how much further you've moved on the route, not just along your velocity vector.
After a few seconds, though, that projection will stop moving, too, when the gap between last fix and now gets too large.
ADS-B is not a guidance tool and will not lead to any more usage of GPS for guidance than is currently common - and certainly won't impact ILS. They're just totally different use-cases.
https://ipadpilotnews.com/2019/09/ads-b-traffic-when-does-it...
https://www.faa.gov/nextgen/programs/adsb/faq/#x8 You probably have a much large hole in your coverage than you thought.
Maybe if it's shown to be a great practical problem, they'll address it. If not, then no they won't. I'm guessing they won't.
* https://en.wikipedia.org/wiki/Multilateration
* https://www.radartutorial.eu/02.basics/rp52.en.html
* http://www.multilateration.com/surveillance/multilateration....
This can further be cross checking with space-based systems like Nav Canada's:
Even jamming near Nellis and Area 51 is done by NOTAM and not perpetual.
Maybe there is some permanent jamming somewhere but pilots would know about it as GPS availability knowledge is safety critical.
It was my job to "help" with the navigation, using a paper chart and VOR/NDB steam gauge instruments. Dad was able to teach 10yo me how to do this stuff, but it was easy to confuse from/to or think you are tuned to station x when actually you are on Y, etc. Particularly night VFR was hard to be sure you were exactly where you thought you were. We did not fly over open water at night.
Later we got a primitive GPS, no maps just waypoints and lat/lng. That thing was so much easier to use it was night and day. Just dial in a 3 letter code for your airfield, and you get range,bearing,eta.
GPS is a huge improvement to safety and convince, but if it goes out a night or in bad weather there are gonna be some problems.
I've had kids ask me what we did before we had GPS and Google Maps and I tell them that we got lost or turned around a lot more often.
https://en.m.wikipedia.org/wiki/Tethered_Aerostat_Radar_Syst...
As you'll see from the various documentaries, historically planes operating illegally and/or doing illegal things will fly "under the radar" and keep their transponder turned off to evade the authorities.
They'll do the same thing with GPS.
I feel like, for example, I'd be worried if fine-detail GPS data was being published live for example, or live enough to predict where the plane is "right" now...
Any time my dad takes his personal plane up for an hour's flight, I get a text message and can watch his track (and altitude/speed) in real-time.
The FAA in the US does publish a 'privacy list' of aircraft whose owners have requested that they not be included in services like this, and most commercial providers comply with that list, but enforcement is sparse and several hobbyist projects (e.g. ADS-B Exchange) do not and even emphasize aircraft that have put in such a request, since the tend to be a bit more interesting. A bit of a Streisand effect.
The same situation exists with the similar AIS system used by ships at sea, and has produced concerns over malicious use, but there continue to be plenty of websites that will show you maps of ship locations picked up by their contributing AIS receivers.
Almost all.
If you're flying VFR you can put your transponder into an anonymous / incognito mode (if it supports it):
* https://www.avweb.com/aviation-news/faa-acts-to-preserve-ads...
If you want IFR or flight following you'll have to de-anonymized, which is no worse than it was before ADS-B.
Does incognito mode in your browser stop you from being tracked if e.g Google or facebook can see every or almost all of your requests?
So people can see that someone is in a particular place, but not who that person/plane is.
I very much doubt that we'll get to even 80% of the fleet of FAA registered airplanes having ADS-B out by 2030. We're at about 50% right now.
https://www.faa.gov/nextgen/equipadsb/installation/current_e...
Radar can be jammed too, but I would guess the EM signature powerful enough to track. I don't know if GPS jammers would have that issue.
On a positive note, I think this would pave the way towards integrating commercial drone infrastructure into our airways a lot better!
We still have it, and our commercial planes have been required to have ADS-B transponders here for more than a decade. This is just for en-route tracking.
that's only a plus if you're not expecting malicious interference. how much harder is radar to spoof compared to GPS?
According to the crew on the USS Zumwalt they can make a 600' ship look as large as a cruise ship or as small as a fishing vessel. This ship is covered in radar absorbent materials and has a giant phased array to accomplish this.
EDIT: Apparently Loran C was discontinued in 2010.
[0]https://en.wikipedia.org/wiki/Loran-C [1] https://www.stripes.com/news/break-out-the-sextant-navy-teac...
What does "still maintain" mean in this context? My Loran-C receiver stopped working years ago when we turned off the signals.
https://en.wikipedia.org/wiki/Loran-C#Loran-C_in_the_21st_ce...
Most airplanes already rely heavily on GPS for their own navigation. If GPS is being jammed (or having any other clear issue) they'll fall back to their many other redundant navigation instruments.
If you want to be scared, be scared about spoofing of ILS signals, where a couple of dozen feet of error can be fatal.
https://arstechnica.com/information-technology/2019/05/the-r...
*all radar.
Certainly around airports radar will be kept, but there are a few (remote?) places where aging infrastructure will not be replaced.
On the plus side, there are areas that had no coverage (Gulf of Mexico) which now get traffic information from receivers that are easier to run than radar towers.
Based on my experience, ATC Radar have no difficulty seeing commercial aircraft with a high probability of detection and low probability of false alarm.
Source: completed a performance assessment of several such systems in the early 2000s against their legacy counterparts using aircraft beacon systems as a source of “truth”.
If I remember to come back to this later, I’ll write a little post showing the theoretical detection performance of such a system. If you’d like to try the exercise yourself, the relevant worksheet is a Blake Chart and you can look up surrogate parameters for the Radar via checking the ASR-XX pages on Wikipedia (e.g. ASR-9 or ASR-11). Finding Radar cross sections (RCS) for commercial aircraft models is similarly straightforward. The system is logarithmic so as long as you’re in the ballpark you’ll be close.
The JSS is a descendant of the SAGE system developed during the Cold War to detect soviet aircraft. It has a reduced equipment footprint, but this is generally due to improving radar technology, coverage is similar and the backend data processing systems are much more advanced. The majority of radar sites belong to and are maintained by FAA but report directly to the Air Force air combat system.
Consider that controllers currently rely primarily on secondary radar, which while more difficult to spoof than ADS-B is still quite subject to malicious manipulation. They are well aware that a primary radar return with no corresponding secondary radar information is something to sort out, and this won't change with a switch to ADS-B.
I'm not sure exactly what equipment is installed there, I found an older report listing an ASR-8 at that location but that system is obsolete and inconsistent with a newer list showing it as a secondary (SECRA) site only.
There is also flow control that is from the FAA — under IFR the acceptance rates are reduced.
The short answer isn’t that SFO isn’t “upgraded” but the rate of aircraft acceptance is reduced under low visibility conditions per the FAA — and for good reason, separation of aircraft.
Here is more explanation: https://media.flysfo.com/media/sfo/media/weather-operations-...
>GPS reception may be unavailable or unreliable over a large portion of the southeastern states and the Caribbean during offshore military exercises scheduled between January 16 and 24.
https://www.aopa.org/news-and-media/all-news/2020/january/14...
Considering that, I suspect the aviation industry will keep both systems working for a surprisingly long time.
If GPS were to become the sole way to do the latter, every airplane would effectively get an invisibility cloak that those who want to do evil can activate (and even worse. Switching off the on-board transmitter is less scary than spoofing signals)
Because of that, I would expect they keep using some way to detect planes that don’t tell them where they are, or radios broadcasting “plane P is at X,Y,Z” without a plane being there.
This is already the case. Much of the civilian radar system already relies on transponders to get a good fix on aircraft, via secondary radar. Primary radar coverage (no transponder required) is much more limited. Turn off the transponder and you'll largely disappear from ATC's screens.
ADS-B isn't new in this regard.
Yes, thank you for clarifying. I just explained that I am a pilot, so I did know that.
It was an analogy. Just like the way that pilots have multiple redundant "where are you tools", so too do I think traffic controllers will have multiple redundant "where is everyone" tools.
Because the industry, as a whole, is in favor of multiple redundant tools when it comes to safety.
Existing non-ADS-B based traffic management requires accurate altimeters and working transponders; we have always been at the mercy of systems that can fail. One of the many reasons for the substantial training of pilots.
On the plus side, lots of opportunity to create cockpit displays, warning devices etc to increase pilot safety!
So that's a good thing? interesting.
Not everything in life is free.
The Kessler syndrome is when collisions between objects cause a cascade in which each collision generates space debris that increases the likelihood of further collisions.
There's a legitimate concern that over-reliance on GPS will cause massive financial and loss of life damage in the civilian sector if it's ever denied through jamming or kinetic attacks or solar storm etc.
https://www.reuters.com/article/us-china-space-report/analys...
Global navigation constellations are certainly going to be one of the first targets in any major hot conflict between world powers.
Realistically, a solar storm is a more likely and less predictable threat. The end result is the same, any critical functionality that relies on GPS will be denied for a prolonged period of time.
Do you have a cite for this?
Other thing I completely forgot to mention is that all existing global navigation constellations orbit at MEO, not GEO. Which puts them within speculative range of demonstrated ASAT weapons and allows for even longer reach from a launch vehicle like LGM-30.
This doesn't make sense to me. Could you explain further? LGM-30 is a land-based ICBM designed to strike targets on the surface of the Earth, and hence to take a (just barely) sub-orbital trajectory <13,000 km from point-to-point, with maximum altitude a few hundred km. Wouldn't its thrust capability have to be drastically upgraded to reach 20,000km in altitude, where MEO satellites like GPS are?
A derivative of the LGM-30, Minotaur, is used to launch satellites (or ordnance) directly to GTO @ ~30,000km.
(though i agree that kessler concerns are overblown.)
If you have an actual GPS app there's typically a diagnostic screen where can see where the satellites are and see them arrive and disappear from your perspective as they orbit.
But if SA was enabled:
Before it was turned off on May 2, 2000, typical SA errors were about 50 m (164 ft) horizontally and about 100 m (328 ft) vertically
https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_...
[1] https://www.skybrary.aero/index.php/Ground_Based_Augmentatio...
ADS-B doesn't change anything about how a plane navigates. That's still done with a plethora of redundant instruments, all working together.
[1] https://www.gps.gov/systems/gps/modernization/sa/faq/#on [2] https://archive.defense.gov/releases/release.aspx?releaseid=...
GPS satellites will not have the hardware to do selective availability in GPS III, which are currently being launched:
* https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_...