NBAA, AOPA Press Authorities On GPS Jamming


AOPA and NBAA say the FAA and the U.S. Air Force need to figure out how to minimize the effects on civilian aviation while they test the hardness of military GPS. There are almost always NOTAMs warning of potential GPS outages as the military intentionally jams signals for training and research. The groups say they understand the need for the testing, but it’s disruptive and potentially dangerous for others using the signals. “The NAS has become increasingly reliant on GPS as the primary source of navigation and aircraft system functionality while reducing the ground based navigational backup infrastructure,” the joint letter reads. It also notes the tests are on the increase and the government agencies have said they will continue to expand.

In 2017, the FAA asked the Radio Technical Commission for Aeronautics (RTCA) for suggestions on how to minimize the impact of the testing on the rest of the system. The RTCA submitted a dozen ideas in early 2018 but the FAA and USAF have been silent on what they think of them. “Therefore, NBAA and AOPA are seeking a detailed briefing and update on the status of that industry report, including the work done over the past several years to help provide operational relief,” the letter says.

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  1. Looks like we’re “evolving” toward fly-days and no-fly-days.
    Better dust off those Sectional charts.
    Can’t wait to see what the FAA proposes as “mitigation measures” against drones.
    Brave. New. World.

  2. It’s another example of the folly of depending on one basket.

    Dare I say ‘e Loran C’? 😉

    Well, there are IRS, for a price.

    And software to combine and compare sources of navigational information.

    • Good GPS-based navigation systems having detection of anomalous signals, needed even without jamming.

      OTOH, spoofing

      Decades ago, people trying to use USN VHF Comm signals for navigation learned that, when 747 command post airplanes tested transmitting to submarines via a long trailing wire antenna and lots of energy from onboard generators.

  3. First… GPS was never designed for civil aeronautical navigation. This is a military targeting system that people found very useful in other areas.
    When I first suggested using the GPS signals for aircraft tracking (instead of radar) in the late 80s it was immediately turned down by both the military and the FAA. The signal was far to easy to jam. They went through a lot of trouble putting in WAAS stations and other equipment to bolster the GPS signal so we could use it for navigation and ATC aircraft tracking. They are now attempting to learn how to jam the improved signal, so the GPS signal can not be used to target US.
    The entire purpose for jamming is to effect navigation. The location is selected for pilots to have other options like VORs to navigate with during these periods of testing.
    Mitigating jamming is kind of silly, but has been done to the best of the militaries ability. This jamming location causes the least problems to air navigation where GPS is really needed due to the lack of other available navigation aides.

    • Don’t you mean LAAS to improve GPS accuracy? Once SA was turned off, WAAS satelites replaced LAAS.

      The military is coming up with a new military only version of GPS. They don’t say it but I’d BET that IF a need arose (like on 9/11), they’d turn off GPS in a heart beat.

  4. Any pilot, private or commercial, who navigates solely by GPS to get from point A to point B, is asking for trouble. Regular cross referencing with charts/navaids as well as pilotage, should be practiced. With visual reference to the ground, looking outside to verify one’s position shouldn’t be that difficult.

  5. I finally pulled my LoranC after the signals were shut down. I did not equip for IFR GPS nav for many years until finally forced into it by the discontinuance of the localizer approach in favor of a RNAV/GPS with LPV. While it brought the DH down several hundred feet, it mandated IFR GPS/WAAS equipage. I am now in the process of putting a Dynon Skyview in the airplane. In discussions with the Dynon following, I told them I was laying out the panel to keep my ADF, Stormscope and at least one VOR/ILS radio in addition to the GPS. While the FAA is decommissioning NDBs as fast as it can, and I shot the last NDB approach into an airport before they pulled the beacon, they are not decommissioning broadcast radio which will still give me a path to VFR weather where i can see the ground and at least find an airport. I was based near ABQ when the LightSquared nonsense was underway.

    As has been mentioned, regular cross checks with charts/navaids and pilotage should be practiced, and are, in the clouds, or over the clouds, the loss of ground navigation stations is increasingly reducing this particular system redundancy, and this includes the FAAs concerted effort to further reduce all ground stations, including VOR, forcing us to be completely dependent on GPS, which is a central component of NEXGEN. We are hooked on GPS and there is no way back, unless they restart the Loran chains and I plug the old box back in the airplane.

  6. Bravo for Keith S–“don’t put all of your eggs in one navigational basket!”

    I was scheduled for a flight in our King Air to Denver area today–during the height of the near-record snowstorm. The flight WOULD be flyable–barely–IF the runways could be kept open (NOTAMS mentioned the snow deep enough to bury the lights!). I also found that four VORs on the arrival/departure routes were out of service. OK, GPS will still work–EXCEPT for the NOTAM that today was the day that the military would be “conducting an exercise” that would degrade GPS–no arrivals/no departures–no approaches. The ILSs still worked–IF you could get to them (radar vectors) and IF the runways could be plowed.

    What ELSE could go wrong? The TSA announced a TFR for “VIP” in the Denver area. Scrubbed the trip.

    It got me to thinking how ELSE I could have navigated the trip. Loran? Gone (but the Loran station tower) is till stacked on site at Baudette, MN.–wouldn’t take much to recommission it). We used to use the old VLF system–(gone). Inertial (haven’t used one in years). There are SOME VORs still available enroute to Denver–if only I had an old KNS-80 radial-distance offset system!

  7. Years ago, when GPS navigation was first coming out, I attended an FAA Press briefing at Oshkosh. Somebody asked about GPS jamming–the FAA speaker was candid–“There is nothing we can do about the military jamming GPS.” Have you ever wondered why your GPS sometimes doesn’t work in the SW states? It’s because of military jamming exercises–does anyone recall the outage along the Pacific Coast a few weeks ago? It seems a Navy Destroyer participated in an exercise, didn’t turn off the jamming, sailed from San Francisco to San Diego–and diddled every GPS approach along the way!”

    The assembled aviation press people were dumbfounded, “The government giveth, and the government taketh away.”

  8. Probably the only way someone at the FAA will come up with a solution is when a Representative or Senator can’t get home or into DC because the airline he/she is riding on can’t navigate due to a GPS outage. It’s amazing what can get done when a politician gets inconvenienced.

  9. “It’s amazing what can get done when a politician gets inconvenienced.”

    Absolutely brilliant and correct Matt! Can you imagine the heads that would fly (no pun intended) if a politician was aboard a commercial airplane when an announcement comes over the PA stating they have lost their primary navigational equipment due to military jamming…and they will proceed with caution using 75 year old technology to get them there. I can see this as a basis for a sequel for Airplane!

    Since so many drivers and pilots have become “children of the magenta line”, I would assume a bunch of truck drivers, automobile drivers, bass fishermen, and boat owners also get the features/benefits and consequences of the military jamming of GPS. Can you imagine the confusion of Biff and Muffy when the nav system of their Beemer goes belly up sending them over the tracks to the other side of town?

    • Commercial airliners use a combination of IRS Inertial Reference System (laser ring gyros) and GPS. Combined, the accuracy is close enough to get you lined up with the runway and over its threshold. ILS is still required for full autoland capability. IRS/GPS/WAAS provide VNAV to lower minimums. IRS only (GPS jammed) is still more accurate than VOR navigation and allows for point to point nav. Airlines can continue to operate into any airport with an operating ILS/LOC without GPS. It’s pretty unlikely that any politician will be inconvenienced by GPS outages.

      • The only airliners that have that kind of nav equipment on board are those used for oceanic flights, not domestic. Most domestic especially regional don’t have more that the usual dual VOR/ILS and some GPS. Keep in mind the FAA gave the airlines a 5 year grace period before they are required to have WAAS enabled GPS receivers for Ads-B, something GA did not get. Several airline companies did not want to spend the money needed to install WAAS enabled GPS for older planes that were going to be retired.

  10. I’ve often wished for a FM based NDB.

    As a student pilot, I loved keeping a NDB dialed in for SA. Simple, straight to the “point”, and no brain capacity lost thinking about to/from inbound/outbound from a VOR. It was a real treat to pretend I was “lost” and able to get my SA back with a couple of NDBs, sometimes only 1.

    So then, got me thinking. VORs are much more complicated (maitence/money) to upkeep than a simple NDB. Yet, they are quickly decommissioning NDB sites…yet still, it’s often that I see, at least a radial or 2, “out of scv” on a VOR- if not the entire VOR…and they are talking about decommissioning more and more VORs..

    So, a simple ground, FM based NDB, I think would be neat. Not at widespread as AM, but not as much atmospherics to deal with. AC equipment would likely be smaller with a smaller antenna. You could even incorporate DME.

    So, where could we find such a transmitter? How about all the ADSB ground sites? I believe the ground site sends out an ID. I know the lat/long of that ID, take two and I’ve got a fix. Add a DME signal to the ADSB ground site, maybe need only one then.

    • I love how one part of government forces us to use GPS and decommissions the back up systems, then another branch of government decides to randomly turns off what the other required us to use. The internet wasn’t designed for your personal use either, yet I suspect you’d complain (via letter to the editor?) if they randomly turned it off.