The US Air Force’s new Stand-In Attack Missile is showing potential as a versatile weapon to hold time-sensitive targets at risk thanks to its employment of a millimetric radar seeker.
Northrop Grumman’s AGM-88G Advanced Anti-Radar Guided Missile-Extended Range (AARGM-ER) appears to be a gift that keeps on giving. The weapon is forming the basis of the Stand-In Attack Weapon (SIAW) air-to-surface missile. The company won the contract to develop the SIAW for the United States Air Force (USAF) in September 2023. Reports note that the SIAW is expected to enter service with the USAF in 2026. Defence Express revealed in late November 2024 that the weapon was being earmarked as a potential strike capability against Short-Range Ballistic Missiles (SRBMs). SRBMs typically have a maximum range not exceeding 540 nautical miles/nm (1,000 kilometres/km). One potential target mentioned in the Defence Express article is the 9K720 Iskander (North Atlantic Treaty Organisation reporting name SS-26 Stone) SRBM. The 9K720 has been used extensively in the Ukrainian theatre of operations and open sources state the missile has a range of up to 270nm (500km).
Millimetric Wave
A key capability of the AGM-88G is the Millimetric Wave (MMW) radar seeker accommodating the missile. MMW seekers also equip Northrop Grumman’s AGM-88E and Raytheon’s AGM-88F HARMs (High Speed Anti-Radiation Missiles). Alongside the AGM-88G, these latter designs are the latest variant of the venerable AGM-88B/C HARM. HARM has been a scourge of ground-based air surveillance and fire control/ground-controlled interception radars since its introduction into USAF service in 1985.
The MMW radars transmit at frequencies above 30 gigahertz/GHz. These frequencies can depict targets in impressive detail. Tactically, this helps ensure the missile strikes the correct target. For example, the Radar Cross Section (RCS) of a hostile radar can be cross-referenced with an internal library of targets. The radar’s processor will match the RCS of the target with the internal library and perform the attack. Likewise, the missile can abort its attack if the RCS differs greatly. Sources close to the AGM-88E/G programmes have shared with Armada in the past that the MMW radar also aids battle damage assessment. Radar imagery can be sent by datalink from the missile to its launch platform. This imagery can be examined after the attack to ascertain the quality and effectiveness of the strike.
HARM and Iskander
Armada spoke to a senior radar engineer who confirmed that the MMW capability of the AGM-88E/F/G could offer kinetic options beyond hitting only radars. They mentioned that RCSs for targets like 9K720 launch vehicles could be stored in the missile’s radar seeker. As before, the missile’s radar could match this RCS with the imagery it is collecting for target confirmation before performing the attack.
The engineer said that loading the SIAW with RCSs of threats like the 9K720 could have added benefits. The missile could be launched in a loitering mode. With its radar activated, the SIAW could continually search for a target like an 9K720 launcher across a specific area in the radar’s field-of-view. Once such a target is discovered, the missile will press home its attack. A variant of this tactic would be to launch the missile into a pre-defined area where an Iskander launcher is, but perhaps where exact coordinates are unknown. The missile will search for the target in this area and attack the threat once discovered. The engineer continued that the missile’s blast fragmentation warhead could do significant damage to a 9K720 launcher and its missiles. A single attack could possibly take both out of the fight altogether. In fact, the radar seeker could be programmed with a myriad of time-sensitive targets on the ground.
Despite being originally developed to hit hostile radars the AGM-88E/F/G design is showing itself to have impressive tactical utility. It may not only be radar operators who fear HARMs in the air, and the damage that they can do.
by Dr. thomas Withington
