GPS Spoofing... Watch your Assets.

BEEF SUPREME said:
Never took a course but I taught myself celestial navigation while working aboard the tall ship Alvei. At the time I was a super nerd disguised as a surfer. The working on different sailing ships was a neat way to see the world and I had always wanted to teach myself celestial nav. We were at sea so much on Alvei I had enough time to figure it out. I had a cheap sextant. Pretty sure it was plastic. A small handheld HF radio for a time hack. H0249 the air navigation tables and a how to book: Celestial Navigation for Yachtsmen, by Mary Blewitt. And the nautical almanac. By the end of my time on Alvei I could reliably shoot stars, the planets and the sun. I never could figure out how to shoot the moon. The math was too hard for me to sort out on my own. Maybe with some help I could have figured it out.

I could fix my position within about 3-5 miles. Not bad for an idiot.

Fun fact: HO229 was the tables for navigation at sea, HO249 for air. The sea tables were extra complex for a better position fix and was considered by everyone as overly complicated.

Yes. Mary Blewitt is a real name as far as I know.
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Through our kids (or more appropriately, the mom’s workout group my wife is in), we became friends up here with a couple that spent many years sailing tall boats together. He and I sort of talk past each other a little bit, since we speak a similar but not common language, but his stories of captaining tall boats are pretty interesting. The guy is as nerdy about nautical stuff as i am aviation. Side note, his wife does shipboard electrical stuff, mostly on yachts moored locally, but man, she is sharp. She and my wife are good friends, and I’m hoping that one day, she will teach her to do this stuff in our house :) I dont think i got better than a B in the undergrad electrical engineering courses i had to take. Electricity and me aren’t friends.
 
///AMG said:
Through our kids (or more appropriately, the mom’s workout group my wife is in), we became friends up here with a couple that spent many years sailing tall boats together. He and I sort of talk past each other a little bit, since we speak a similar but not common language, but his stories of captaining tall boats are pretty interesting. The guy is as nerdy about nautical stuff as i am aviation. Side note, his wife does shipboard electrical stuff, mostly on yachts moored locally, but man, she is sharp. She and my wife are good friends, and I’m hoping that one day, she will teach her to do this stuff in our house :) I dont think i got better than a B in the undergrad electrical engineering courses i had to take. Electricity and me aren’t friends.
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New callsign: Sparky


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///AMG said:
Haha i know a sparky. Loved spooling her up about the vaccine, or WA state taxes (she was a small business owner, owned a brewery with her front seater husband)
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Did you catch the name of former tall ship captain guy? It’s a super small world.

Response might be better via DM.


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Minuteman said:
Most of the jamming I've seen has been happening deepinnaheartuh of the Ankara FIR.

The only spoofing I've seen was in the US for near Quantico.
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It’s probably good that I brief that NOTAM during change over flying through Ankara.
 
Ops group in the last few days reported of an aircraft getting some jamming on the NAT tracks.

Airbus put out an informative tech notice about jamming.

GNSS Interference | Safety First

Signals from the Global Navigation Satellite System (GNSS) are one of the main inputs used for aircraft positioning or time reference for Communication, Navigation and Surveillance functions on-board most of the Airbus aircraft.Operators report an increasing number of events related to the loss...
safetyfirst.airbus.com
 
mattc206 said:
Ops group in the last few days reported of an aircraft getting some jamming on the NAT tracks.

Airbus put out an informative tech notice about jamming.

GNSS Interference | Safety First

Signals from the Global Navigation Satellite System (GNSS) are one of the main inputs used for aircraft positioning or time reference for Communication, Navigation and Surveillance functions on-board most of the Airbus aircraft.Operators report an increasing number of events related to the loss...
safetyfirst.airbus.com
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I saw that. There was also an update from Bombardier in their manual.
 
This is an issue I have been tracking closely due to upcoming flights to/through the affected areas.

There is a general mis-understanding that these GPS spoofing events are causing loss of, or inaccurate IRS position. That is not true in any large cabin Gulfstream. The micro-IRUs only receive GPS signal for initialization. They do not receive any further inputs after that. What crews are erroneously reporting as loss of IRS is the loss of the Hybrid function. For those who are not familiar, the modern Gs have a Hybrid IRS-GPS function. On the Position sensor page it shows in order: FMS position; Hybrid IRS 1; Hybrid IRS 2, Hybrid IRS 3, GPS 1, then on the second page GPS 2, IRS 1, IRS 2, and IRS 3.

The Gulfstream manuals are not helping the issue as they are not accurate in their terminology when they say the IRS receives updates inflight. It is not the actual Micro-IRU receiving that update, it is the Hybrid system. That actually makes sense if you stop and think about it. The IRS will drift after initial alignment. If you don't believe me then go to the IRS Status page and see the drift amount 10 hours into a flight. It has not been corrected by any outside signals.

So, when these events are happening there is a filter that compares the FMS, IRS, and GPS position. An initial big change in the GPS will not necessarily reflect in the hybrid position right away. The FMS could still be using that sensor for navigation because it has not drifted to a worse level than the pure IRS or any DME-DME or VOR-DME sensor. Once it does the system should choose the most accurate sensor, which is often DME-DME over land. The sensor in use can be seen on Progress Page 1.

Both Bombardier and Dassault have suggested deselecting the GPS sensors prior to operating into known areas of spoofing. I know Emirates, who transits the area all the time, is also doing that. Gulfstream/Honeywell are working on a bulletin, but it is slow in coming. Their initial bulletin left a little to be desired, but their idea is similar to the Airbus article. In the event of a jamming situation it is best to just leave the system alone. With loss of GPS signal the system will revert to the next best sensor. The spoofing issue is another matter. The only way to make sure you don't get a course deviation is to deselect both GPS and all 3 Hybrid positions so that you force the system to use the next best sensors, DME-DME, VOR-DME, or IRS. Not that I am recommending that, but that is what would make sure the FMS is using an unaffected sensor.
 
typhoonpilot said:
This is an issue I have been tracking closely due to upcoming flights to/through the affected areas.

There is a general mis-understanding that these GPS spoofing events are causing loss of, or inaccurate IRS position. That is not true in any large cabin Gulfstream. The micro-IRUs only receive GPS signal for initialization. They do not receive any further inputs after that. What crews are erroneously reporting as loss of IRS is the loss of the Hybrid function. For those who are not familiar, the modern Gs have a Hybrid IRS-GPS function. On the Position sensor page it shows in order: FMS position; Hybrid IRS 1; Hybrid IRS 2, Hybrid IRS 3, GPS 1, then on the second page GPS 2, IRS 1, IRS 2, and IRS 3.

The Gulfstream manuals are not helping the issue as they are not accurate in their terminology when they say the IRS receives updates inflight. It is not the actual Micro-IRU receiving that update, it is the Hybrid system. That actually makes sense if you stop and think about it. The IRS will drift after initial alignment. If you don't believe me then go to the IRS Status page and see the drift amount 10 hours into a flight. It has not been corrected by any outside signals.

So, when these events are happening there is a filter that compares the FMS, IRS, and GPS position. An initial big change in the GPS will not necessarily reflect in the hybrid position right away. The FMS could still be using that sensor for navigation because it has not drifted to a worse level than the pure IRS or any DME-DME or VOR-DME sensor. Once it does the system should choose the most accurate sensor, which is often DME-DME over land. The sensor in use can be seen on Progress Page 1.

Both Bombardier and Dassault have suggested deselecting the GPS sensors prior to operating into known areas of spoofing. I know Emirates, who transits the area all the time, is also doing that. Gulfstream/Honeywell are working on a bulletin, but it is slow in coming. Their initial bulletin left a little to be desired, but their idea is similar to the Airbus article. In the event of a jamming situation it is best to just leave the system alone. With loss of GPS signal the system will revert to the next best sensor. The spoofing issue is another matter. The only way to make sure you don't get a course deviation is to deselect both GPS and all 3 Hybrid positions so that you force the system to use the next best sensors, DME-DME, VOR-DME, or IRS. Not that I am recommending that, but that is what would make sure the FMS is using an unaffected sensor.
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If you're going to talk about Gulfstreams you should also mention the original IRUs that've worked on a G-IV for 40 years are unobtainium, not because they're faulty. Honeywell decided to stop supporting their product and won't allow anyone else to repair or overhaul them, but at the same time they offered an almost plug in upgrade (for $800.000). I've watched perfectly solid airplanes get parted out because Gulfstream and Honeywell refuse to support their product. The folks that own these airplanes have deep pockets but some have just thrown up their hands and said "I'm out.". Gulfstream, the pinnacle of private aviation hates their customers, if you have a new 650 under warranty you might get them to jump a little bit when you need help, if you have a G-IV you'll have to pay them for the right to ask them to even stand up. I say this as someone who's worked on these contraptions for a long time.
 
knot4u said:
If you're going to talk about Gulfstreams you should also mention the original IRUs that've worked on a G-IV for 40 years are unobtainium, not because they're faulty. Honeywell decided to stop supporting their product and won't allow anyone else to repair or overhaul them, but at the same time they offered an almost plug in upgrade (for $800.000). I've watched perfectly solid airplanes get parted out because Gulfstream and Honeywell refuse to support their product. The folks that own these airplanes have deep pockets but some have just thrown up their hands and said "I'm out.". Gulfstream, the pinnacle of private aviation hates their customers, if you have a new 650 under warranty you might get them to jump a little bit when you need help, if you have a G-IV you'll have to pay them for the right to ask them to even stand up. I say this as someone who's worked on these contraptions for a long time.
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I’d hate to find out what it would take if you had a G-1 or G-II? :)
 
knot4u said:
If you're going to talk about Gulfstreams you should also mention the original IRUs that've worked on a G-IV for 40 years are unobtainium, not because they're faulty. Honeywell decided to stop supporting their product and won't allow anyone else to repair or overhaul them, but at the same time they offered an almost plug in upgrade (for $800.000). I've watched perfectly solid airplanes get parted out because Gulfstream and Honeywell refuse to support their product. The folks that own these airplanes have deep pockets but some have just thrown up their hands and said "I'm out.". Gulfstream, the pinnacle of private aviation hates their customers, if you have a new 650 under warranty you might get them to jump a little bit when you need help, if you have a G-IV you'll have to pay them for the right to ask them to even stand up. I say this as someone who's worked on these contraptions for a long time.
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Why do you hate capitalism so much? They’re just doing what’s best for the shareholders.
 
Did no one else regularly lose GPS signal when flying between the MOAs SE of TRM? Used to happen to us regularly enough Corning back to CRQ that center would just say "oh they're jamming again? Fly present heading and direct TRM when able."
 
MikeD said:
I’d hate to find out what it would take if you had a G-1 or G-II? :)
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I've fueled G-I's, but I never worked on one. I basically cut my teeth on 20 series Lears and G-II's. Thankfully for those of us that maintained them our government finally decided they'd had enough, not because they were bad airplanes but because they're too loud. There were some airplanes that were grandfathered in if they had hush-kits installed. Magic Johnson still had a G-III in 2020, a member here was his captain, I don't know if that's still true. There are two old Gulfstreams I never minded working on because they were well maintained and not abused, Merle Normans G-II and Magics G-III. Somehow both of those airplanes managed to somehow avoid the pitfalls that seem normal with most older jets. I knew Normans DOM/mechanic and eventually they were flying with half an autopilot that repairing was impossible because no one supported the mysterious boxes that make the magic happen, it also leaked fuel like sieve and he'd built a cart with a huge tray on top and a 55 gallon drum underneath that he'd wheel up under the the keel beam after it was towed into the hangar. Having a dirty hangar floor is a bad look but it gets weird when you have airplane up on jacks for a couple of days to work on the gear. Eventually it was replaced by a solid G-IV, probably 2018?, it was supposed to go to the family museum but it either got scrapped or went south. Both airplanes had immaculate interiors that had been updated over the years and unless you were very discerning looking at a photo you might think it was a G-IV. I understand capitalism, but orphaning these things seems like a bad way of retaining your base customers. If you own a G-IV and need brakes, an IRU or a windshield good luck ( the 550 uses the same windshield as a 4 ).
 
Boris Badenov said:
They got us good coming over the Black Sea tod...er yester...I dunno, recently. We were on INS for maybe 20 minutes. Through our Herculian efforts of sitting there and monitoring the situation mightily, we still got where we were going.
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As always, love the sarcasm. But, you know, what actually happened?
 
form810 said:
As always, love the sarcasm. But, you know, what actually happened?
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Oh, I was quite serious (or as serious as I ever am). We checked the Nav page, put the little snowflakes on the MFD, and went on our merry way. It was a non-event. The damned thing has a lot of tech in it, and generally speaking, it works pretty well.
 
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