Magnetic Navigation

Magentic Navigation

Short version, using the earths magnetic field and variations to navigate in case we lose GPS in future conflict.

This brought to mind a question about civil aviation. Let’s say the balloon goes up and suddenly satnav of whatever sort is down (destroyed, jammed, etc). How workable is the American/Western civil aviation sector? I know there has been a move away from radio nav aides the past decade relying much more heavily on satnav solutions. Would we see the aviation sector grind to a halt, or would it be capable of function largely business as usual excepting more weather diversions and a lot less GA IFR flying?

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That sounds like Kevin Miller’s Fight Fight.

I’ve kind of been out of the RL aviation scene for a while, but are traditional NAVAIDs going offline?

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Flying within line of sight with Russia often cause our GPS signal to be jammed. It doesn’t effect approaches, as the earths curvature shields us at approach altitudes. But we’re pretty dependent on satellite based or augmented navigation.
A few years ago, we actually encountered a sort of Y2K phenomenon as our Flight Managment Systems database reset the calendar. Turns out that when they designed the hardware, nobody thought the units would be used for more than 1024 weekly update cycles, or roughly 20 years…
Suddenly the system calculated the RAIM for a totally different date and flagged every GPS based approach.
While the producer scrambled to find a solution to the issue, we had to resort to old school navigation like NDB approaches, that our new hires only had read about or had been shown in a sim once. That was fun! :laughing:
And as satellite based nav systems are much cheaper to maintain, ground based nav systems will slowly disappear into history.


Interesting, having to resort to techniques and instruments that pilots haven’t really practiced is what I was thinking might happen. How well did that go for everyone?

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I used to work for a startup, technology of which used magnetic field for indoor navigation. I think they are now doing all kinds of sensor fusion for creating indoor maps and navigation.

Basically the required tech is built in every smart phone.

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Well, the NDB approaches still available are more or less cloud break procedures, meaning the minimum altitude is quite high above the terrain, so there were no real problems.
But the issue with jamming has brought up discussions about the need for inertia NAV systems. These are much smaller and much more precise, these days, compared to pre GPS era models.

Should we lose satellite nav capability, we would see interruptions in air traffic. At least in the beginning, until alternate procedures has been eatablished and trained for.

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This reminds me of a time many moons ago when I was tasked with taking a group of junior soldiers who were about to attend the promotion course for Corporal on a nav revision exercise.

It was when we were revising resections (determining position by triangulation) one of the young soldiers pulled a ‘brick’ out of his pack (very early civvy GPS receiver) and said “what do I need to know this for Corp, I’ve got a GPS”

“Hand it over Digger, let me have a look at that” said I and proceeded to remove the batteries.

Giving it back I said “What are you going to do now smartarse”… OK class the first thing you need to know when doing a resection is…

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I think that air traffic flow would be restricted, but not necessarily thrown back into the ‘30s.

There is I believe an effort to retain some level of Navaid coverage by most nations for obvious reasons. That is at least until an entirely self contained Nav system can be designed.

In the short term though, I think that most transport category aircraft are capable of reverting to some version of lower grade navigation, like DME/DME/IRU, which looks a lot like GPS nav to the pilot(i.e. waypoint nav)…at least enroute.

In the terminal area ILS is still the gold standard for larger airports. For smaller fields, I think they’re far more likely to retain VOR over NDB just for the ease of maintaining newer gen technologies. Radar is still, to a large extent, used to maintain separation. So, while efficiency will be severely affected, it’s not to say that the skies will revert to reporting points and tracking maps.

In this case though, I think you will see GA traffic grounded. Throughput will be too limited and ATC too saturated to allow for what might be considered optional operations.

Of course in that kind of war, $100 hamburgers will probably be the least of people’s concerns! :wink:

I think domestic commercial travel could handle loss of GPS without missing a beat. In the US, ground based navaids are kept serviceable for just this sort of hit. Oceanic travel would be slower because the current RNP requirements would be impossible.

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I don’t know about the US and the primary radar coverage, but over here ATC mostly use SSR or get aircraft position from the ADS-B, which in turn gets its position from the GPS…

We have a mix of both. But radar is still available in all places it has been prior to satellite surveillance so the loss of ADS information wouldn’t be much of a setback. I can count on one hand, make that NO hands, the number of times I’ve shot an instrument RNAV approach in the last couple of years. The US is a bit behind western Europe, I think intentionally.

Not sure that’s a bad thing though…
They seem all too eager to remove ground based stations over here.

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Interesting, I still get RNAVs not infrequently assigned and some places seem like they are ramping up on them. LAX seems like they are going whole hog.

Of course, ILSes are a hundred times easier (at least the way we do it) and you get better mins.

The FAA has been trying to fob off the cost of maintaining the NAS (through elimination of NAVAIDs and pushing GPS) for quite awhile. Most airlines are having none of it.

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A U2 guy told me years back that this is why we keep the fleet. They still work with just a man and a map. Maybe not well but they work.


Pre- GPS, at least in the USA, up through mid-90’s, for long-range Nav, controllers had simple tools to vector you from point A to point B; we’d routinely do it from S. California to, oh, nearly the East coast (as far as we could get away with - never too close the final destination for reason you all know)

Just had to update their heading (sometimes it was not always done in a timely manner) periodically. In my memory GPS-equipped aircraft were the exception until, roughly, the mid-90’s in the US.

We’d use, for lack of a better term (we had no official term), “Kentucky Windage”, ie; we’d get the initial number from, say PKE VOR to CVG VOR and you 'd add a little ‘lead’ knowing that mag. var. was an issue.

GPS sorta took some of the fun out of it.

So assuming the RADAR’s and radios still work (and the afore mentioned NAVAID’s) it’s not a big deal. That’s a big assumption, right?: RADAR’s I assume would be prime targets? “Big Sky Theory” is a thing but RADAR, really (out side the obvious SA and separation thing), was to keep everyone from showing up over the numbers all at the same time.

And up until 911 there were more planes in the air (and more airlines) even. Things would get a little crazy, multiple times per day. No idea the numbers after about 2011.