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Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

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Re: Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

#101

Post by briandear »

FabHK wrote: post #76
jrockway wrote: post #67

A lot of comments seem to be about spoofing. Remember that there are multiple humans in the loop -- experienced pilots and experienced air traffic controllers -- and multiple levels of redundancy. Pilots have access to barometric altitude, radar altitude, traditional VHF navaids, TCAS-issued resolution advisories (based on directional antennas, not GPS)... in addition to GPS. Air traffic controllers have primary rada…

> 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 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.

https://www.telegraph.co.uk/travel/destinations/oceania/aust...

It happens rarely, but pilots are also trained to not blindly follow clearances. They are still pilot in command.

Re: Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

#102

Post by tialaramex »

jessriedel wrote: post #81
akiselev wrote: post #75

Earlier quoted context omitted.

GPS satellites are in geosynchronous orbit, far above any threat of Kessler syndrome and we won't have nearly enough material in orbit that occlusion of the satellites would become a problem for centuries, if ever.

GPS satellites are indeed at much higher altitudes and thus well protected from (highly speculative) worst-care Kessler syndrome scenarios, which occur in low-Earth orbit (<2,000 km altitude). However, GPS satellites are not in geosynchronous orbit (35,7000 km altitude) but rather operate in a medium Earth orbit of about 20,000 km.

Indeed. The GPS birds zip around, a GPS device has to learn (traditionally from GPS itself but downloading from the Internet is much faster if you have Internet and these days most devices can do that) where the birds are in order to turn its relative distance from each satellite into an absolute position on the Earth's surface.

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.

Re: Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

#103

Post by sokoloff »

mc32 wrote: post #37
simonswords82 wrote: post #31

Earlier quoted context omitted.

They simply won't turn their GPS on.

Won’t they have to before takeoff? Or will that not be a requirement?

The overwhelming majority of airspace under 10K feet in the US does not require ADS-B out.

https://www.faa.gov/nextgen/equipadsb/research/airspace/

Re: Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

#104

Post by ufmace »

jcrawfordor wrote: post #89
ufmace wrote: post #74

Regarding posts about spoofing and maintaining radar, it was my understanding that the radar sets that most ATCs used was not actually powerful enough to get direct returns from commercial aircraft, and relied on amplifying transponders to be able to see them. Supposedly only militaries operate radars powerful enough to see aircraft directly. Can anyone who knows more confirm or deny? If that's true, I guess we're al…

In the US, ATC radar and military radar are one and the same - the FAA and the Air Force share the Joint Surveillance System (JSS). So, while the JSS has plenty of limitations (including plenty of areas with no coverage even in the mainland US), it's designed to meet the military objectives of being able to locate even non-cooperating aircraft. The JSS is a descendant of the SAGE system developed during the Cold War…

Well that's interesting. How does that tie in to the story's reported change though? I suppose ATCs might be willing to rely solely on aircraft-reported location and speed, but I kind of doubt the USAF would. If they share the same systems, I suppose no equipment would actually change or be decommissioned.

Re: Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

#105

Post by UncleOxidant »

code4tee wrote: post #14

Radar isn’t going away. This article talks as if ADS-B is replacing radar, which it’s not. It’s enhancing radar where radar coverage exists and providing coverage on traffic where radar coverage currently does not exist (usually lower altitudes away from major airports and over the ocean).

Oh, good. I can't read the article (paywall) but was hoping they weren't actually replacing radar with GPS. Using GPS to enhance radar seems a lot better.

Re: Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

#106

Post by zentiggr »

LargoLasskhyfv wrote: post #98
korethr wrote: post #94

Earlier quoted context omitted.

I'm kind of wondering if there even needs to be. If you keyed up on frequency near a major airport as described in the GP, I'm pretty sure the FAA and FCC would be working together to track you down in short order. I could see the argument that it would be good to add authentication to the radios to complement the strict enforcement for a sort of belt-and-suspenders approach. However, I think a more pressing concern…

Could they? A moving target? Say the soundproofed back of some van.

I personally would volunteer to be on one of the teams in another van with directional antennas to triangulate your transmissions and shut down you ASAP.

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.

Re: Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

#107

Post by sokoloff »

o-__-o wrote: post #9
mattlutze wrote: post #3

If there's anyone in the air control technology industry here, I'm curious what parts of this change get you really excited, and which parts get you really nervous?

The cost. This affects general aviation as older planes will require avionics upgrades. Otherwise I’m excited for the sheer amount of data that will be made available to the public. Now you will be able to track all FAA registered planes

> track all FAA registered planes

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...

Re: Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

#108

Post by ryandrake »

sokoloff wrote: post #100
gryphonshafer wrote: post #52

A valuable part of the ADS-B out mandate is that planes even as small as mine (a.k.a. tiny) can cheaply (<200$US) pick up ADS-B in and display it on a consumer tablet. My private airplanes now have pseudo radar. Not every airplane in the air is broadcasting, but most are. This is a huge safety win. Almost without exception I'll see airplanes on my tablet long before I have visual on them.

Without ADS-B out on your airplane (which you don't have for 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.

Fortunately (unpopular opinion among pilots) the FAA is slowly phasing in ADS-B out as required equipment. Starting Jan 1 of this year, you need to tx ADS-B if you're anywhere you'd otherwise need a Mode-C transponder, including around many airports.

Re: Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

#109

Post by Patrick_Devine »

FabHK wrote: post #76
jrockway wrote: post #67

A lot of comments seem to be about spoofing. Remember that there are multiple humans in the loop -- experienced pilots and experienced air traffic controllers -- and multiple levels of redundancy. Pilots have access to barometric altitude, radar altitude, traditional VHF navaids, TCAS-issued resolution advisories (based on directional antennas, not GPS)... in addition to GPS. Air traffic controllers have primary rada…

> 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 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.

The problem with _requiring_ authentication is that it can create a safety issue when communications break down. As a pilot it's not a bad idea to carry a spare handheld radio, or even use a cel phone, when you lose communications.

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.

Re: Air-Traffic Control Is in the Midst of a Major Change from Radar to GPS

#110

Post by sokoloff »

ryandrake wrote: post #108
sokoloff wrote: post #100

Earlier quoted context omitted.

Without ADS-B out on your airplane (which you don't have for 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.

Fortunately (unpopular opinion among pilots) the FAA is slowly phasing in ADS-B out as required equipment. Starting Jan 1 of this year, you need to tx ADS-B if you're anywhere you'd otherwise need a Mode-C transponder, including around many airports.

Nit: Starting Jan 2
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