The USMC’s F/A-18 Hornets Are Getting New Jamming-Resistant GPS Gear

The updated antennas and electronics will help keep the jets combat capable in the face of increasingly common electronic warfare attacks.

byJoseph Trevithick|
F/A-18 photo


The U.S. Navy, on behalf of the Marine Corps, is looking to add jam-resistant GPS antennas to more than a hundred of the latter service’s F/A-18 Hornet fighter jets. Given the increasingly real threat of a potential opponent, such as Russia or China, cutting off American forces from the navigation system, this could be an especially important upgrade for the aging jets, which the Marines expect to fly for at least another decade.

On June 27, 2018, Naval Air Systems Command (NAVAIR) announced it was looking for defense contractors who could install the equipment on 120 F/A-18C/D aircraft in a notice on the U.S. government’s main contracting website, FedBizOpps. If the project moves ahead as scheduled, the Navy hopes all of the modifications will be complete by September 2022. This is the same timeframe in which NAVAIR expects to upgrade the radars on some of the Marine jets, as well.

NAVAIR is interested in an upgrade that would consist of antennas that are “equivalent or similar” to BAE Systems' AS-4654/A Conformal Controlled Reception Pattern Antenna (C-CRPA) and the Raytheon AS-4616/A Advanced Digital Antenna Production (ADAP) Antenna Electronics (AE). The Navy began installing the C-CRPA on top of the existing ADAP system on its F/A-18E/F Super Hornets and EA-18G Growlers in 2017.

The C-CRPA is actually a unit containing seven distinct elements, which sits flush in the fuselage to reduce drag. Combined with the ADAP equipment, the system improves the ability of the aircraft to receive GPS signals despite any jamming and other electromagnetic interference. The plane’s GPS receiver itself remains unmodified.

A US Marine Corps F/A-18C Hornet., USMC

Though the NAVAIR notice refers the Marine F/A-18C/D aircraft, it appears the plan is to add the anti-jam capability to all 120 aircraft in the service’s active duty squadrons. This includes a number of even older A++ models, which first entered service in the 1980s, according to the Marine Corps’ official 2018 Aviation Plan.

The service has another approximately 60 F/A-18A-D aircraft assigned to reserve and training units. There is no indication from the NAVAIR notice that these planes would be part of this particular upgrade plan.

There is also a possibility that the Navy might intend to add some or all of these new antennas into the F/A-18A-D aircraft it is planning to retire and send to the Marine Corps in the coming years. The Navy announced that plan in March 2018 and hopes to have completed the transfers by the end of 2020, which would be almost two years ahead of when NAVAIR expects to have all the anti-jam equipment installed in the Marine jets.

The updates will be important for whichever specific jets end up receiving them since the Marines expect to be flying so-called “Legacy Hornets” through at least 2030. The hope is by then there will be enough stealthy F-35 Joint Strike Fighters to take their place.

A US Marine Corps F-35B Joint Strike Fighter flies in formation with a pair of the service's F/A-18D Hornets., DOD

Developmental and production issues with the F-35 have forced the Marines to push back the date for finally retiring the F/A-18A-Ds more than once. This is in many ways a self-manufactured situation since the service decided it transition straight from Hornets to Joint Strike Fighters without purchasing any other fighter jets, such as the Super Hornet, in the interim.

So, in the meantime, the Marines’ Legacy Hornets will have to soldier on in the face of steadily increasing threats, including GPS jamming. And just in the last year, the need to operate in a potentially GPS-degraded environment has gone from a future concern to a very real issue.

In August 2017, there were reports that Russian GPS spoofing was impeding naval traffic in the Black Sea. Two months later, there it appeared that Russian GPS jamming as part of the massive Zapad military maneuvers had caused disruptions in navigation services across Scandinavia.   

These developments have since morphed into more serious reports of unknown actors in Syria, likely Russia or Syrian government forces it supports, engaging in overtly hostile activity. In April 2018, there was a flurry of news regarding attempts to knock out the GPS links on some American drones flying over Syrian territory and threats to those or other electronic systems onboard AC-130 gunships operating in the region.

Russia's 1RL257E Krasukha-4 mobile electronic warfare system, one of many different such systems the Russian military has at its disposal., Vitaly Kuzmin

“Right now in Syria, we’re in the most aggressive EW [electronic warfare] environment on the planet from our adversaries,” U.S. Army General Raymond Thomas, head of U.S. Special Operations Command, said at the U.S. Geospatial Intelligence Foundation’s 2018 GEOINT Symposium. “They’re testing us every day, knocking our communications down, disabling our AC-130s, etcetera.”

Also in April 2018, there were reports that Chinese forces were actively engaged in similar tactics to dissuade or otherwise limit the ability of American forces to fly over the South China Sea. There has been evidence dating back to 2013 that China been interested in doing this as part of a broader anti-access strategy to prevent foreign militaries, especially the United States, from operating in the hotly contested region.

This is the reality Marine aviators will increasingly find themselves in. The service’s Hornets already contribute, from bases on land and as part of U.S. Navy Carrier Air Wings, to operations in Iraq and Syria and in the Pacific. They could be called upon to deploy elsewhere, including in and around Europe, in a crisis, too.

Without the added resistance to hostile GPS jamming, those aircraft could find themselves unable to adequately perform their assigned missions. For Carrier Air Wings especially, this could present a significant interoperability problem given that the Navy’s F/A-18E/Fs and EA-18Gs already have the upgraded antennas. That service stopped flying its own Legacy Hornets off carrier decks in April 2018.

A US Navy F/A-18C Hornet from the "Blue Blasters" of Strike Fighter Squadron Three Four (VFA-34), which became the last of the service's units to fly Legacy Hornets from carriers operationally in April 2018., USN

It’s very possible that other countries might be interested in adding the upgrades to their own Legacy Hornets, too. In particular, Finland, which has grown closer to Western Europe and NATO to the ire of Russia, and Australia, which faces the same potential threats from China in the Pacific, could see the anti-jamming equipment as equally essential for their jets. Australia might have retired its Legacy Hornets by the time these upgrades become widely available, though. Canada, Spain, Malaysia, and Switzerland also operate older F/A-18s and the former two countries are NATO members, as well.

Any of those other Legacy Hornet operators could decide to add the improved antennas to a larger upgrade package. This could include a broader service life extension update, as well as a new “glass” cockpit and other improved missions systems, such as a new active electronically scanned array (AESA) radar and an improved electronic warfare suite. An AESA radar by itself would significantly improve the aircraft’s ability to detect and engage hostile aircraft more precisely and at longer ranges, something the Marines have already realized when it comes to their jets. This would also allow them to take advantage of increasingly longer-ranged air-to-air missiles.

Of course, for the Marines, the lack of anti-jamming equipment, or any other updated mission system, might not be the biggest problem. The availability rate of the service’s F/A-18A-Ds continues to be exceptionally poor.

Marines work on a Hornet onboard the carrier USS Theodore Roosevelt in 2015., USN

In February 2017, it emerged that nearly three-quarters of all Marine Legacy Hornets weren’t even airworthy at any one time on average. Just to get there, the service had raided the Bone Yard at Davis Monthan Air Force Base in Arizona and a museum for critical parts and even entire replacement aircraft. As of Jan. 1, 2018, the Marines had 100 out of approximately 270 aircraft “out of reporting” for heavy maintenance alone, according to their own annual Aviation Plan.

Hopefully, the new anti-jam antennas, along with the other upgrades the Marine Corps is looking to add to its Legacy Hornets already and its plans to get entire newer jets from the Navy, reflect a larger push to revitalize the service's increasingly neglected F/A-18 community. By the end of 2022, the Marines may be flying a 'Super' Legacy Hornet that is the most capable of its type to date.

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