Words of Advice:

"If Something Seems To Be Too Good To Be True, It's Best To Shoot It, Just In Case." -- Fiona Glenanne

"Flying the Airplane is More Important than Radioing Your Plight to a Person on the Ground
Who is Incapable of Understanding or Doing Anything About It." -- Unknown

“Never argue with stupid people, they will drag you down to their level
and then beat you with experience.” -- Mark Twain

"Stay Strapped or Get Clapped." -- probably not Mr. Rogers

"Eck!" -- George the Cat

Sunday, April 29, 2018

Knife Fighting in the Dark; the Civil Side

(The military side)

One of the side-effects of a war between adversaries with first-world comparable EW gear will be a loss of the GPS network. Whether it will be world-wide or localized to the combat area(s), whether the GPS constellation itself will be disrupted is a matter of speculation.

But what will also likely happen is a disruption of the global air traffic system. The short-sighted beancounters in the FAA have been pushing the decommissioning of a large chunk of the VOR network and shutting down VOR/DME -based approaches. In the event of such a war, less than two hundred "safe" airports will retain the capability to conduct VOR-based instrument approaches. All of the rest of the airport that had VOR-based or NDB-based approaches will be shit out of luck.

Besides that, putting all of the airspace control eggs into satellite-based systems is betting on that there won't be any significant solar flares.

In some ways, it doesn't matter very much. Some airliners can't track a VOR. Their navigation systems use GPS and overlay the VOR approach on their GPS displays. So while it may look as though they're flying a VOR approach, they really aren't. Losing GPS would transform those airplanes into VFR-only which would effectively ground them all, as they'd be fuel-sucking pigs at VFR altitudes.

Time was, we had redundant systems of navigation. When IFR airplanes had ADFs, the location of the higher-power AM radio stations were on the navigation charts. It wasn't fun drawing lines-of-position on charts in a cockpit, but it could be done. (See, chapter five of Fate is the Hunter ) High-end airplanes several decades ago had OMEGA and LORAN. Microprocessors made LORAN usable in small aircraft and boats.

It's more than airliners and boats. The trucking industry is dependent on GPS. GPS units ensure that truckers avoid parkways and low bridges. It's far more accurate than the old road atlases. Crop-dusters use GPS to precisely apply their chemicals. Farms use GPS to micro-customize the management of their fields. EMS uses GPS to navigate to the site of the emergency. If you call 9-1-1 on your cell phone or hit the emergency button on your car's nav system (or OnStar), the car sends your GPS location. The clown who stalked you and is wearing an ankle bracelet so he stays away from you while he's out on bail-- want to guess how that thing works?

If the GPS constellation is degraded or disabled in a war, the effects will be far-reaching beyond what most people can fathom.


GolFoxtrot Yankee said...

In addition to your accurate observations, the reliance of commercial and recreational shipping and boating on GPS is likely worse. If you want to see ports and marinas grind to a halt, disrupt the GPS network.

And I suspect gravity being what it is the alternate GPS systems (GLONASS, Beidou, GALILEO, etc) are in the same orbit so fragmentary damage to one impacts them all. Please don't go out of business, map and chart manufacturers.

CenterPuke88 said...

During the last Texarkana radar outage, one of fifteen or so aircraft responded correctly to the announcement “Radar Contact Lost, resume non-radar reporting”. The correct answer, of course, is “N123AB estimating TXK at 1900Z, PRX at 1924Z, BYP next.”, the usual answer was silence and me asking for their estimates. ADS-B is showing up more, which is great, but won’t matter for shit when the GPS goes down.

Comrade Misfit said...

I'll bet that the number of ships that have sextants and the tables to make use of them are few and far between. Let alone the mariners who know how to take morning stars, evening stars and what to do with sun lines.

dinthebeast said...

Even the construction industry uses GPS: Kiewit has GPS units on the Cat blades to ensure the correct elevation of each layer of roller compacted concrete in the Oroville dam spillway.

-Doug in Oakland

DTWND said...

Budget cuts by the bean counters at the FAA began around 1985ish. Instead of routine maintenance, it became 'fix-on-fail'. Next, it was 'do we have another way to identify the outer marker?' It eventually evolved into eliminating the VORs.

Additionally, unless the name of the approach is "VOR/GPS ***", one cannot use the GPS to fly a VOR approach. The pilot has to navigate using the VOR signal from the FAF in. For a LOC or ILS the signal must be used prior to intercepting the final approach course.

ATCS (ret)

bmq215 said...

Positioning system outage during wartime would seem to be very much a MAD style scenario. Even without shared orbital planes, the communication frequencies are all very close (in the case of BeiDou and Galileo, overlapping). This means that the jamming potential for all is relatively similar. So it comes down to which nation relies on it the most. We're certainly in the running for that, but in a situation with relative parity I can see anti-positioning moves being a no-go (at least anti-satellite ones, regional jamming would still seem worthwhile, especially if one combatant had EW superiority).

I'll note that everything from the F-35 to the Abrams to the Apache to the JDAM has an inertial navigation system. Often this is integrated with GPS but it would be crazy not to provide some provision for independent operation. How well does that work? I expect that's classified. But it seems likely that GPS outage isn't the silver bullet that it might appear to be.

Anonymous said...

In 2012 there were almost 800 VORs in operation in the continental U.S., an awful lot more than was originally planned. The notion that the whole national airspace will go belly up if the GPS goes away is bogus. The minimum operational network (MON) of VORs is plenty to provide the coverage to get from wherever you are to either VMC or a place with an ILS.

Most modern airliners (and medium to high end GA) use RNAV anyway, derived from TACAN or DME traditionally and nowdays from GPS and called PBN. Modern airliners also use inertial systems too to provide RNAV. First I saw these in civilian aircraft was 1976 or so on a UAL 747 that had 2 of them. Sorry if you don't want to spring for a new panel for your old 172, agree it doesn't make economic sense to spend more than the a/c is worth on new radios, that's why there is a MON, for now.

So Satnav is jammed every day someplace, and twice on Sundays, and no it is not a global war thing. I have a lot of respect for the old school who can do NDB approaches accurately, or L/MF range approaches, or GCAs or whatever. But the fact is time marches on and things change and you either keep up, get run over, or pick another race.

GPS and WAAS has already been jammed to a fair the well with personal privacy jammers bought online and delivered from places overseas..check the history of SATNAV based approaches at Newark NJ. These are illegal but that doesn't seem to bother anyone that uses them. Radar detectors, generally built with grade Z components with no QC also emit like anything on one of the GPS frequencies and make dandy jammers. Like the intentional jammers they are also easy to find, track, and arrest the bozos using them.

Jamming GPS is easy given the well known frequencies and low power on the signals, the brute force jamming can be done by monkeys. But to do that you must be line of sight with whatever receiver you are trying to jam. And if you are line of sight and transmitting I can see you with your RF beacon and neutralize the jammer. It is much more difficult to detect and defend from attacks that walk off the clock little by little to progressively give an erroneous position solution or launch one's own airborne spoofer that impersonates a GPS satellite (the equipment is easy to find, it is a GPS signal generator used in test sets) and you only need a weather balloon. GPS and Galileo are very similar in similar parts of spectrum and design. GLONAS is not, uses different time difference of arrival approach. Biedou is similar to Galileo and GPS but uses different modulation technique. Just knowing the frequency for brute force jamming is one thing, but the modulation techniques using phase shift keying and burying the useful signal data inside a pseudorandom number string so big it would take all of NSA's computers a long time to break it, if ever is another. And you haven't talked about MTSat (Japan, with another name a few years ago) and India has their own constellation too.

CenterPuke88 said...

MON is a joke. MON will work for the airlines because they fly high enough to get the signals, the little guys in the weeds are hosed. Amusingly enough, for a planned decommissioning process, the people in charge of planning departure and arrival procedures apparently were never given a list of the MON VORs, because most procedures seem to use the ones that are to be decommissioned. The expense of redesigning, flight checking and publishing them isn’t minor, and thanks to the terms of the contract for publishing new fixes, etc, will take almost a decade...unless we freeze all other airspace changes till that’s done.

Burr Deming said...

Same general philosophy goes to much of private industry. Banks were unenthusiastic about disaster recovery efforts until Dodd-Frank mandated it. When I fly, I try not to think about the possibility that some executive might have decided that a final safety check was less economical than the more remote possibility of catastrophe.

Comrade Misfit said...

Burr, as long as you stay off Allegiant, you might be OK.