U.S. Air Force Developing New Nav Technology As A GPS Backup


The U.S. Air Force announced this week its Life Cycle Management Center (AFLCMC) at Robins AFB in Georgia is developing “the next generation aircraft navigation system.” In response to concern over GPS jamming by adversaries, the USAF initiated study on the Resilient Embedded Global Positioning System/Inertial Navigation System program—shortened to “R-EGI” in military-speak.

Lt. Col. Robinson Hughes, AFLCMC material leader of the Position, Navigation, Timing [PNT] Office said, “Our mission is to make sure the United States military and those of our allies can navigate anywhere around the globe whenever they need to. We all are reliant on U.S. GPS, and adversaries are developing capabilities with the potential to disrupt our way of life. Plus, there are natural events that can disrupt satellites. What happens if we don’t have access to GPS?”

“By branching out to other sources of PNT,” Hughes added, “like using other global navigation systems and nontraditional sources like celestial navigation, we increase the probability that our aircraft can navigate anywhere they really need to be.” According to an Air Force statement, the R-EGI Navigation System prototype is currently under development and is expected to begin flight-testing in 2024.

Mark Phelps
Mark Phelps is a senior editor at AVweb. He is an instrument rated private pilot and former owner of a Grumman American AA1B and a V-tail Bonanza.

Other AVwebflash Articles


  1. Celestial navigation would be cool and pretty much immune to jamming. I wonder what kind of accuracy it could achieve with today’s technology.

      • Other shortcomings:
        – Equipment size: Putting a telescope on a weapon is a nonstarter. Putting large equipment on small aircraft like UAS is a nonstarter.
        – Positional Accuracy: Not that good compared to GPS.
        – Partial Solution: Only provides position information, not time, velocity or heading with sufficient accuracy.

  2. I can’t help but wonder if they are sorry they cancelled E-Loran which would have had the capability to be almost as accurate as GPS. We will now never know. Our achilles heel is our GPS Satellites. And the Chinese and Russians know it.

  3. An inertial system that is occasionally synched with GPS or ground stations has been proposed by many, for decades.

    • I remember when our USAF Aircraft Delivery Unit on Guam briefed the receivers (Usually Fighter Gaggles) for flights across the Pacific, and the tanker (KC-135) contingent would sorta hint that they would ‘affirm’ their navigation calculations with the IMUs installed on the fighters. They also had a Duck Butt C-130 orbiting at Bingo coordinates to aid their journeys, particularly when single-engine receivers were flown.

  4. US Gov`t killed our Loran navigation GPS backup

    Like many aircraft operators I removed the King Loran reciever from my plane to make room for the ADS-B installation. I am thinking the decision to shut down the Loran system was pretty lame. The auto pilot in my aircraft quit working in flight when the system was shut down .The autopilot was coupled to the Loran receiver. More than 200,000 US civilian and military aircraft and boats had Loran receivers.. Consider that a single F-22 costs $350 million including developmental and other costs and for the price of of one aircraft, we could have operated the entire LORAN-C system for more than four years. But the Department of Homeland Security ordered the Coast Guard to shut down and demo the LORAN stations back in February 8, 2010 .
    So what? Doesn’t the Global Positioning System (GPS) do the same thing and better? It guides unmanned aerial vehicles, tells troops and their supporting arms exactly where they are, synchronizes time and cell-phone antenna, navigates ships. Sure it does, until it fails, or an enemy disables it. Then what do we do? A good answer was to keep a backup LORAN system, and even upgrade it to the enhanced version, e LORAN, which was planned and other countries keep in operation..

    Many think that disabling the satellite system that powers the GPS is unlikely because terrorists won’t be blowing a satellite out of the sky.This maybe true, but it’s relatively easy to cripple the GPS without shooting down a satellite because a space system has two other vital segments — the low power up-and-down links and the ground station. The links can be neutralized by electronic assault. North Korea has done this. The ground station is vulnerable to a variety of stoppages, including mundane factors like power outages and even simple human error. The solution of course is to have a backup system in order to prevent the chaos of a disabled GPS — a chaos that could cause a crash of our financial system — a problem that would make the annual $36 million cost of operating LORAN look like peanuts.

    Another dollar comparison is in order. The estimated cost to upgrade LORAN-C to LORAN e , which could operate for at least 20 years,was $150 million. The projected cost of eight new GPS satellites is $1.8 billion, in addition to launch and operational costs.

    If this minor cost of continuing the LORAN system seems to be a no-brainier, then what happened? Lawrence Husick explains a senior fellow in the Foreign Policy Research Institute’s Center on Terrorism and Counter-Terrorism, wrote that the LORAN system “lacked powerful contractors and lobbyist who could profit from Lorans operation and congressional sponsors.These remote radio installations that bring few jobs, and dollars had no support.” In short, he says, “Loran is an orphan.” There is no money to be made by defense contractors. The Coast Guard maintained the system as part of its job description. He adds that February 8, 2010 marked the day the Department of Homeland Security put the entire nation at risk despite the protest from pilots to the FAA.

    Conclusion: “It is easy to see how a small system like Loran just got lost in the shuffle of bean-counters trying to cut corners.” The conclusion: We were penny wise and pound foolish. We could spend a few pennies to prevent a navigation melt down one day and it may be coming soon. George Gould pilot @ Galceston Scholes airport KGLS Galveston Texas

  5. Definitely need a backup, but as usual, simple answers won’t satisfactorily resolve the problem. As well as being inherently low rate, less accurate and requiring a fairly extensive worldwide network of easily targeted ground stations, LORAN has the same weakness to jamming as GPS, plus that jamming & spoofing can be done from a distance. Celestial and inertial both have their own weaknesses, so the real answer will be a complementary meld of multiple techniques.

  6. Celestial Nav… imagine that… Back in the days of the ASN-24 and ASN-35 computers on the C-141A, we sure got around the world just fine. The Nav did 3-star fixes and the -24 had a Star Tracker that we never really used. Then, the Delco Carousel 4 had Tacan and DME-DME updating and found those same places very accurately AND we didn’t have the Navigator stealing box lunches! (just kidding about the Nav). In the 747 Classic, the Delco then the Litton 92 were extremely accurate. Could update both from the VOR / DME. On the “tracks”, without updates, the -92 would be within a wingspread width of the aircraft that had GPS before we did.
    Loran, GPS, etc, all can be spoofed, flummoxed, or simply jammed. If it is electronic, it can be messed with, period. Thus, for this discussion, only inertial-type systems are relatively safe. They still have to be EMP hardened though.
    Long ago, and kind of far away, another pilot, myself, a Navigator, and a Crew Chief, took 3 C-131s (CV-340) across the Pacific (2 west, 1 east) with naught more than DR, Consolan, and a Sextant. Modern systems are wonderfully accurate and useful but the Mark I eyeball and planning will still work.

  7. That’s all well and good for the military, but what about the civilian world? It’s more likely that an adversary would try to disrupt civilian air traffic by jamming GPS.

    Any radio-based navigation system can be jammed, but if multiple navigations systems are spread over multiple frequency bands, it makes it more difficult to completely shut down air navigation. And I’m not convinced that the VOR MON will leave enough of a backup. Sure, VORs and LORAN aren’t perfect either, but VOR+LORAN would have left a fairly robust backup system to GPS. It also seems like it wouldn’t be too difficult to integrate LORAN and GPS into the same receiver so they can both cross-check each other.

    Inertial and celestial navigation are of course naturally resistant to jamming, but they also require every aircraft to be equipped with them. I hope this doesn’t turn into another mandate for GA aircraft.

    • That’s fine for VFR down low, but not particularly helpful when you’re in IMC or the flight levels.

  8. There’s a reasonably cheap and easy answer for most of us (i.e. the US civil aviation sector). I read a paper a few months back on the possibility of using the ADS-B ground stations as a backup RNAV source. If I recall correctly, the ground station signals included the necessary data to do an accurate time-of-flight calculation. You need have to have an accurate timing source onboard (not an atomic clock of your own, just a good digital clock), at least three towers in view, and a modest microcontroller to crunch the numbers.

    The team that did the study were able to triangulate a position +/- 20 meters. I’m a bit surprised it hasn’t simply become a standard feature on ADS-B receivers. Here’s a link to the paper: https://navi.ion.org/content/68/2/293