GPS Outages around DFW

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Lindberg

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Lindberg
It's apparently been going on for a couple of days. Anyone have any info?

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Military claims it’s not them. Probably someone at a truck stop taking a nap and using a GPS jammer so dispatch can’t track them. :)
 
RyanShort1 said:
Still happening today. I can definitely confirm.

The system is way more fragile than most of us would like to think...
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What worries me the most is that they haven't yet figured out what's wrong and fixed it.
 
5g system bleeding over?
 
There was a law enforcement conference in Dallas last Friday through Tuesday... I wonder if a GPS jamming vendor was demoing a product?
 
FPK1 said:
There was a law enforcement conference in Dallas last Friday through Tuesday... I wonder if a GPS jamming vendor was demoing a product?
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If so, someone will be giving them a talking to, or worse. I would think unexpectedly knocking out GPS without a NOTAM is a big no no.
 
I thought that modern airliners had two antennae on top, and compared the signals. The GPS signal comes from several sources, the blocking from one, so the common signal is subtracted out. The remaining signal is then useful.

I may have the nature of the process a little off, but the research claimed that with the multiple system, blocking or spoofing would not be effective.
 
geezer said:
I thought that modern airliners had two antennae on top, and compared the signals. The GPS signal comes from several sources, the blocking from one, so the common signal is subtracted out. The remaining signal is then useful.

I may have the nature of the process a little off, but the research claimed that with the multiple system, blocking or spoofing would not be effective.
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Two GPS antenna = two GPS receivers. This is common. The units are not comparing the signals. WAAS is the system that corrects errors, but that is from natural processes, not actively signal blocking. GPS signals are very low power, it doesn't take a lot of power on the ground to interfere with them.
 
Yes, two separate receivers, but I thought they made the additional device for filtering out the blocking signal for 121 aircraft after a certain date mandatory. We may not be at that date yet. of course.

Very large noise signals can be removed with modern electronic processes.
 
geezer said:
Yes, two separate receivers, but I thought they made the additional device for filtering out the blocking signal for 121 aircraft after a certain date mandatory. We may not be at that date yet. of course.

Very large noise signals can be removed with modern electronic processes.
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If two antennas and two receivers was all it took to prevent jamming, the DoD wouldn't spend hundreds of millions of dollars on antijam every year
 
Jeff Oslick said:
Two GPS antenna = two GPS receivers. This is common. The units are not comparing the signals. WAAS is the system that corrects errors, but that is from natural processes, not actively signal blocking. GPS signals are very low power, it doesn't take a lot of power on the ground to interfere with them.
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Airliners do have access to LAAS (GBAS). But I think it still depends on receiving something coherent from the satellite.
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in addition to Anti-Jamming properties we are working on with GPS, there is also a self contained NAV system in the works that relies on cameras to recognize the ground and all the associated terrain and structures.

That latter system is no longer classified and has been test flown so satisfactory levels of precision. No kidding!
 
asicer said:
"GBAS capability is standard on Boeing 747-8 and on Boeing 787 aircraft and is an option on Boeing 737NG and Airbus A320, A330 Family/340 and A380 aircraft."
https://skybrary.aero/articles/gbas-landing-system-gls
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There are zero passenger airlines with 747-8s... And I would venture to guess that most US airlines have not bothered to pay for that capability on their narrow-body aircraft, and maybe not the widebodies either. Any airline pilots out there fly something with GBAS?

asicer said:
Which came first, SBAS (WAAS) or GBAS (LAAS)?
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WAAS. That was first switched on in 2003, and the UPSAT CNX 480 navigator, the first certified unit for GA, came out that year. Garmin later bought UPSAT because they were having trouble with it themselves, but the GNS 4xxW/5xxW series units came out in late 2004/early 2005.

LAAS was first enabled at Newark in 2012.
 
IK04 said:
in addition to Anti-Jamming properties we are working on with GPS, there is also a self contained NAV system in the works that relies on cameras to recognize the ground and all the associated terrain and structures.

That latter system is no longer classified and has been test flown so satisfactory levels of precision. No kidding!
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That's pretty cool. Machine learning image detection has really come a long way. Would be nice as a backup system during VFR, but can't imagine it would work well in IFR conditions.
 
IK04 said:
in addition to Anti-Jamming properties we are working on with GPS, there is also a self contained NAV system in the works that relies on cameras to recognize the ground and all the associated terrain and structures.

That latter system is no longer classified and has been test flown so satisfactory levels of precision. No kidding!
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So, sounds good, but it also sounds like a VFR system pretty much by definition. I mean, the description is the same description as pilotage, except with a computer doing it.

Substitute radar for camera, and it sounds like the system my neighbor worked on at Boeing, which they put in the first cruise missiles.
 
flyingcheesehead said:
There are zero passenger airlines with 747-8s... And I would venture to guess that most US airlines have not bothered to pay for that capability on their narrow-body aircraft, and maybe not the widebodies either. Any airline pilots out there fly something with GBAS?
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OK, so there's still the 787...
 
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