BEEF SUPREME
Well-Known Member
Do you live near the coast? Do you have access to an unobstructed view of the ocean (horizon) to the south?
Hackers are taking over planes’ GPS — experts are lost on how to fix it
- Thread starter Oxman
- Start date
Do you live near the coast? Do you have access to an unobstructed view of the ocean (horizon) to the south?
SurferLucas
Southern Gentleman
It’s funny because air gapping the INS units from each other and then flagging a disagreement is basically how the old Delco Carousel INS system worked - the ones you’d see on the Concorde, 747 classic, etc:
View attachment 75053
Carousel Control Display Unit, Commercial Airline
Rectangular display unit, with key pad and a dummy display, to be used to enter waypoints and other navigational information for a long-range commercial airliner.This is the display and keyboard, manufactured by the Delco Division of General Motors, for an Inertial Navigation Sysairandspace.si.edu
I’ve never used them but I’ve watched enough old aviation videos to know that the Orange remote button would link them together for INIT POS, then you’d deselect it and the three INSes would float separately for the duration of the flight (which included long international flights with ocean crossings, etc). I believe there was a comparative logic built it that was smart enough where if one unit drifted enough relative to the other two it would alert and then the remaining two would vote that one off the island.
Any retired JC members get to use these things early in their career?
It’s kind of hilarious that Concordes were crossing the Atlantic at twice the speed of sound with these things in the 70s and now here we are in 2023 lamenting how we’ll ever be able to figure out how an INS/GPS disagree in our subsonic airliners.
The answer is simple - it was arrogant for avionics engineers to consider GPS as an infallible truth source. It’s not. Spoofing works by the gradual introduction of error and allowing the systems to update the INS position multiple times… it shouldn’t work that way. Original calculated INS position should continue to be tracked in memory for the duration of the flight and air gapped from each other, just as it was with the old Delco units. Rather than a truth source, GPS becomes a 4th “potential” position source weighted against the others. And since laser ring gyros are pretty darn accurate one can predict how much their maximum allowable drift should be over the duration of your flight - then your computer could cross-check that against GPS. Has the GPS position drifted more than the allowable INS drift? Then you are being spoofed, and your GPS data is bogus - vote kick it and revert to averaged INS position using the pre-corrected values stored in memory.
We definitely have the tech to do this, the current systems are just unequally weighing the inputs. Add in a 5th ground based nav input with DME/DME and we really have no excuse.
During the Falkland’s Conflict, they took those INS’s out of BA VC-10’s to use in the Avro Vulcan’s for the Blackbuck raids.
BEEF SUPREME
Well-Known Member
It’s funny because air gapping the INS units from each other and then flagging a disagreement is basically how the old Delco Carousel INS system worked - the ones you’d see on the Concorde, 747 classic, etc:
View attachment 75053
Carousel Control Display Unit, Commercial Airline
Rectangular display unit, with key pad and a dummy display, to be used to enter waypoints and other navigational information for a long-range commercial airliner.This is the display and keyboard, manufactured by the Delco Division of General Motors, for an Inertial Navigation Sys
I’ve never used them but I’ve watched enough old aviation videos to know that the Orange remote button would link them together for INIT POS, then you’d deselect it and the three INSes would float separately for the duration of the flight (which included long international flights with ocean crossings, etc). I believe there was a comparative logic built it that was smart enough where if one unit drifted enough relative to the other two it would alert and then the remaining two would vote that one off the island.
Any retired JC members get to use these things early in their career?
It’s kind of hilarious that Concordes were crossing the Atlantic at twice the speed of sound with these things in the 70s and now here we are in 2023 lamenting how we’ll ever be able to figure out how an INS/GPS disagree in our subsonic airliners.
The answer is simple - it was arrogant for avionics engineers to consider GPS as an infallible truth source. It’s not. Spoofing works by the gradual introduction of error and allowing the systems to update the INS position multiple times… it shouldn’t work that way. Original calculated INS position should continue to be tracked in memory for the duration of the flight and air gapped from each other, just as it was with the old Delco units. Rather than a truth source, GPS becomes a 4th “potential” position source weighted against the others. And since laser ring gyros are pretty darn accurate one can predict how much their maximum allowable drift should be over the duration of your flight - then your computer could cross-check that against GPS. Has the GPS position drifted more than the allowable INS drift? Then you are being spoofed, and your GPS data is bogus - vote kick it and revert to averaged INS position using the pre-corrected values stored in memory.
We definitely have the tech to do this, the current systems are just unequally weighing the inputs. Add in a 5th ground based nav input with DME/DME and we really have no excuse.
During my first Pacific crossing to Hawaii I was shown "how far off" the IRS was. I was mostly kind of in stunned disbelief because the error was less than a mile. At least for latitude there is a constant: one degree is 60 miles and all the decimal points are tenths hundreds and thousands of a mile.
It's shocking to me how few pilots realize that after a decimal point the first digit is a tenth of a unit and the second digit is a hundredth of a unit. 737 pilots will actually set the trim to 5.72 units. That in itself is ludicrous and it's made even worse that the indicator on the FOs side is often an entire unit out of sync with the the CA side.
I don't understand why the IRS units can't just let it ride until landing. So what if its 10 miles off? That's why the PYE VOR can be detected from 180 miles away and I've personally got my bearing from it over 250 miles away. Two VORs and you have a position fix you can plot. It's so easy.
BobDDuck
Island Bus Driver
Because we've crammed so many airplanes into so little airspace, 10 miles off in mid track could be a huge deal if the other guy is also 10 miles off. It worked fine "back then" because the separation requirements were much, much larger. The Concord could make the crossing at Mach 2 using three basic INS systems because between coasting out and in there was only a few other planes out there. Good luck trying that now on the NATOTS or PACOTS.
Boris Badenov
Fortis Leader
The Legacy vs. 737 crash in Brazil made me a confirmed Luddite w/r/t GPS accuracy. Like maybe it's just fine if we're 500ft off the airway, man! Loosen up, dude, listen to some Steely Dan! *peace sign*
Roger Roger
Bottom of the list
Instead of SLOP need ROP-random offset program. Just scrambles your ANP enough to make sure nobody is in the same spot
CFI A&P
Exploring the world one toilet at a time.
While not ANP, but choose your own offset. It was always fun to do flight reviews with those that fly cross country at 3,700' or 4,200'... "Uh why?" "Because everyone else is at 3,000 3,500 4,000 4,500. This gives me a little buffer." "Except your buffer is encroaching on someone else's. You're halfway between two pilots doing to correct thing."
Roger Roger
Bottom of the list
It’s a big sky
scooter2525
Very well Member
That’s only a theory.
You're giving me Piarco flashbacks. "We're really gaining on traffic ahead of us. Wait, he's headed opposite dirrrr, turn turn! Turn TURN TURN!!!!" ****WHOOOOSH****
I kind of wanted to be an astronaut and aviation was just my 'in'.
Glad that didn't work out because I'd be that drunk at a bar in Houston checking my cellphone waiting to finally get that call as I age-out.
Bob Ridpath
Pit Bull love
I’m not anxious to die, for sure, but I’m certainly glad I won’t have to brave the future which is coming.
I am absolutely positive that AI and technology won’t be the savior of mankind, without the human perspective to guide it.
We gave up much to gain a little.
roundout
VNAV monitor
The army Air Force has entered the chat
Bob Ridpath
Pit Bull love
And yet, to this day, people take “the next left” onto railroad tracks because the GPS told them to do so.
Thinking people need to manage the resource, not blindly depend upon it.
ppragman
FLIPY FLAPS!
Onobstructive not really, I'm in ANC. I could go down to the coastal trail and maybe get a decent view? I've done that before to go start gazing, but not really, unfortunately.
ppragman
FLIPY FLAPS!
Culturally I am convinced there needs to be a better math and statistics component to American education for this exact reason. Like, I get "I set it to 5.72 because that's what is on the checklist and I am fastidious" but also.... "5.73 and 5.71 won't kill you, get it close, correct if need be, flying is a series of errors and corrections."
BEEF SUPREME
Well-Known Member
I’d gladly give you my sextant and books. You’d still need to buy a current nautical almanac and the air navigation tables: H.O. 249
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ppragman
FLIPY FLAPS!
That's very generous but I don't know that I have the vision to actually make that work anymore and I've got a cheap plastic one I bought to learn. I will try with the cheap plastic sextant I got, and if my vision keeps getting better, I'll take you up on that! Lemme get back to you, thanks!
If you're in Anchorage I'll buy ya beer regardless. Do you end up in this part of the world often?
Last I checked it was possible to download the nautical almanac as a PDF? Man, I've got some reading to do.
BEEF SUPREME
Well-Known Member
My example is related to Inigo88’s post. So the context is: why the INS should be completely independent from GPS and therefore unable to be spoofed by bad data. We have exposed ourselves to a threat to navigation by being dependent on GPS.
Also I know it stands as madness to some here but I could fix my position at 3 to 5 miles using stars sun and the planets. AKA, calm down it’s not that bad. Add in ADSB to the mix and the GPS spoofing is a non issue.
With ground based navigation I could narrow that down to about 1/2 mile or less.
And by ground based Nav I mean the lighthouse at the Bay Of Islands, New Zealand on our offshore passage from Suva, Fiji.
You could discern your distance from the lighthouse by shooting the height of the lighthouse through the sextant. So I had a to/from bearing and a DME effectively.
10 miles off to a gate would be pretty awful if the crew was able to plot worth a damn. And they had two or more VORs working.
I imagine that LORAN would make it down to a few hundred feet and one could corse correct from there.
Yet I’ll never know because I was born to late explore the world, born to soon to explore the stars but just in time for these dank memes.
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