Electronic Weapons: Homing In On The Jammers


July 2, 2024: In Ukraine, Russia took the lead in developing electronic jamming technology and Ukraine, the United States and its NATO allies are hustling to catch up. This wartime game of dueling improvements between electronic warfare (EW) and electronic countermeasures (ECM) to electronic warfare has been going on since at least 1940. At the level of small unmanned aerial vehicles, Ukrainian responses to new Russian UAV jamming techniques are currently only ten days behind new Russian advances.

Current Russian local and wide area jamming are making Ukrainian military radios inoperable and reducing the accuracy of GPS guided weapons supplied by NATO. The U.S. has come up with a partial solution to this, a missile that homes in sources of jamming. This capability won’t be available until 2025, and that puts pressure on the Ukrainians to improvise.

This is not a new problem. Two years ago the U.S. sent some AGM-88 HARMs (High-speed Anti-Radiation Missile) to Ukraine. Soon a photo appeared on the Internet showing the debris of a HARM missile used in Ukraine to destroy a Russian air defense radar. The U.S. admitted that some HARMS were being used by Ukrainian warplanes. This is possible via a HARM feature that uses the missile’s own radar detection and homing capability. This is a short-range option, good for detecting and locating a radar up to 50 kilometers distant. The Ukrainian have demonstrated a skill at adapting military and equipment for new uses. Rigging a MiG-29 fighter or SU-25 ground attack aircraft to carry and use a HARM missile in HARM as Sensor mode is feasible. This enabled Ukrainian warplanes to use HARM to shut down the many Russian SAM (Surface to Air Missile) batteries that make it difficult for Ukrainian aircraft to operate freely. The HARM-carrying aircraft come in low and under the radar and fire the HARM when close enough for the detection sensors in the missile to become aware of the SAM radar. At that point the pilot launches the HARM and turns away. Until receiving HARM the only anti-radar missile Ukraine had was a Russian design that lacked many of the HARM capabilities.

The U.S. has lots of HARM missiles and they are continuously improved. The latest upgrade is a major one. Since 2012 the U.S. has been upgrading older ABM-88B HARMs to the AGM-88E/F AARGMs (Advanced Anti-Radiation Guided Missiles) standard. Upgrading older HARMs costs about half as much as buying a new AGM-88E. In most cases AARGMS are created by using the case, rocket motor and warhead of an AGM-88 HARM missile with new components, mainly guidance and control items.

New 88Es cost $1.26 million each. Originally the plan was to produce 1,879 AARGMs but increased demand from U.S. forces and sixteen export customers, including Ukraine led to the current goal, set in 2016, for 2,435 AARGMs. The increased demand was prompted by the improved air defense systems of potential adversaries that rendered the 88B model less effective. Most customers believed potential enemy defenses were still vulnerable to the AARGM upgrade. In 2023 the new HARM model became available.

For over half a century most guided missiles were built with these upgrades and refurbishments in mind. The older missiles not only have more advanced components installed, but the entire missile is examined and any component needing replacement gets that done. Older spare parts for the 88B are also replaced, as needed, with those that work in the 88E. Most AGM-88s are being used on the U.S.-made EA-18G electronic warfare (EW) aircraft, which now takes care of certain EW missions, like SEAD (suppression of enemy air defenses) for the air force and marines as well. To do that they need the latest model HARM. But the U.S. Air Force and Marine Corps aviation also use some HARMs and AAARGMs.

The AGM-88 comes in various models, giving users lots of options. Some users only need the older 88B but most want the latest model. The AGM-88B HARM entered service in 1983 and used a passive radar seeker which homed on enemy fire-control radars emissions in order to destroy the radar and thus render surface-to-air missile (SAM) systems useless by destroying radars needed for target tracking. In 1999 (the Kosovo War against Serbia) the 88B HARM was found to be vulnerable. The Serbian forces limited their radar usage to a minimum and used quick radar shutdown techniques and pack and leave tactics for their SAM units. Because of these tactics, HARM had problems acquiring targets. That’s because the missile has precision guidance only when enemy radar is working all the time. Otherwise, the 88B reverts to offline mode that uses the less accurate INS (Inertial Guidance System) only.

NATO forces failed to silence most Serbian SAMs during the campaign. There were calls for upgrades to the 88B and some software upgrades seemed to deal with the problems encountered against Serbia. But the potential threats kept appearing and AGM-88 upgrades continued and resulted in some major changes and a new model HARM.

Not only is the E model an improved version of the 88B, but it also includes major modifications that enable it to hit moving ships. This makes the AGM-88E an effective anti-ship weapon as well. Meanwhile, another upgrade of the AGM-88 entered service. The AGM-88F is very similar to the 88E but comes from a different manufacturer and is aimed at export sales. The 88F completed testing in 2014 and entered production. This version also has the anti-ship capability.

All these upgrades seen in the 88E and 88F contributed to the missile getting a new name. It’s now an AARGM (Advanced Anti-Radiation Guided Missile) instead of a HARM. AARGM weighs 361 kg (794 pounds) and can detect and attack targets more than 150 kilometers away while traveling at a speed of 2,450 kilometers per hour. The AGM-88E can transmit a picture of the target, just before it is hit, so the user can be certain of what was taken out. The AARGM was developed jointly by U.S. and Italian firms.

The AGM-88F has GPS guidance added with less accurate but jam-proof INS as a backup. The older AGM-88D also used GPS so that the missile, which normally homes in on radar transmissions, could be used to attack targets by location alone. The F model expands on basic GPS capabilities and also includes other features that assist in defeating enemy electronic defenses. What the GPS/INS provides is a way for HARM to act on previous intelligence about where an enemy radar is while also using its radar signal homing capability and new anti-decoy features. Many countries now use a decoy emitter that sends out a fake radar signal to lure the HARM away from the real radar. The 88F model uses GPS and more sensors and new software to get around all known deceptions (and some that haven’t been invented yet).

There is also a longer-range AGM-88G. The AARGM-ER model has a different shape so that it will fit inside the internal bomb bay of the F-35A and C models. The G model also has improved performance including longer range, about 280 kilometers. This is twice the range of other AGM-88s. By carrying these missiles internally, the stealth of the F-35 is maximized. This is essential for the first aircraft encountering enemy air defenses. These aircraft will take out key radars so subsequent SEAD aircraft, like the non-stealthy EA-18G, can do their job with less risk of loss. The AARGM-ER will enter production after 2023 but it is not yet clear if it will replace or just supplement the existing AARGM. The development of the AARGM-ER began in 2016 and has remained on schedule with production starting in 2023.

The AGM-88 moves at high speed, as in 2,200 kilometers an hour or 36 kilometers a minute. The original 1960s anti-radiation missile (ARM) quickly evolved into the HARM. There were initial orders for over a thousand AGM-88E/Fs from the U.S. Navy and Marine Corps, Italy, Australia and Germany. Over 25,000 AGM-88s, of all types, have been produced since the 1980s. Most are never used in combat or for training and are built for a long shelf, or storage, life of about 15 years. Manufacturers have found ways to extend the shelf life of these expensive devices to a decade or more, but often before that limit is reached new models of the missile appear with new features that are often essential to get the job done against enemies that have better countermeasures. For that reason, the trend is for guided missiles to be built to make it easier and cheaper to upgrade key components, like the guidance system, which is quite elaborate for a HARM missile. As time goes by successful missile designs result in more of the older models available for refurbishment and upgrades and this has become a major source of income for manufacturers.




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