The M112 HIMAT (Hypervelocity Intelligent Missile, Anti-Tank) is a man-portable anti-tank weapon used by the USCMC.
The M112 HIMAT consists of a 11.3kg carbon-fiber composite tube, a single-round self-contained disposable launcher supported by a bipod stand and baseplate. The tube incorporates RTM ports allowing for different fire control systems to operate the weapon.
The APS-100 Fire Controller is an 800 Gb intelligent system which in 'Autonomous' mode can analysis data from multiple sources, includig lidar, motion sensors, infrared scanners and robot sentires, to identify and fire upon any targets within range. The APS-100 can also be set to 'Command' mode, where it is monitored by operator from a remote terminal to assist in target identification and authorize weapon launch.
The SR-90 is an infantry-operated target acquisition sight designed specifically for use with the M112 in direct-fire mode. Plugged directly into the RMT port, the SR-90 includes an optic cable 150m in length, allowing the operator to safely fire the M112 from a distance. The sight combines a passive infrared infrared imagining with an active ultrasonic motion detector to identify and lock-on to targets. A new infantry sight, the SR-105, replaces the motion tracker with a millimeter-wave radar, allowing the missile to be targeted at "soft" targets such as bunkers. A new general-purpose warhead is also being introduced to improve its ability against these new target types as well.
The HIMAT missile itself is a small, two-stage round with a range of 5,000m. The first stage launches the missile vertically into the air, while the second activates 1.5 seconds after launch to accelerate the missile almost instantly to speeds of Mach 4.5. Within the nose of the missile is a multi-sensor seeker: a Boekhoven-Bonn Infrared imager in the 8-12 µm range, a Thoreson millimeter-wave radar and superheterodyne receiver areal for homing in on active radar jamming. The seeker scans the vehicle upon arrival and identifies the target's type and configuration from its onboard memory, either to asset the optimum point of attack or veer away if its has been accidentally launched at a friendly target. The warhead itself, located behind the seeker assembly, is a 15cm tungsten kinetic penetrating rod surrounded by LX-28 explosive filling, which is detonated just before impact. The force of the explosion, combined with the hypervelocity of the missile, ensures penetration against all but the strongest tank armor.
During defensive operations, one or more launchers are connected to an APS-100 Fire Controller, which operate in either 'Autonomous' or 'Command' mode, although it can also be datalinked to surveillance drones or artillery FOs. In this set-up, the M112 is used for area-denial operations. During offensive operations, the M112 is deployed in direct-fire mode, with the operator using a SR-90 or SR-105 sight from a safe distance to target and fire the missile.
In addition to tanks, the HIMAT is also somewhat successful at targeting low-flying aircraft such as dropships and helicopters. However, while the intelligence system of the HIMAT is successful at targeting most vehicle's weakpoints, it has been fooled when facing previously-unknown machines. Marines fighting against bugboys using the new French-made CDC-80 tanks found the HIMAT missile couldn't make sense of the new tank, and repeatedly tried (and failed) to penetrate its glacis plate. The Marines were able to sort out the problem after two weeks by updating the system's operating software.
When operating as part of a Marine Assault Unit, each line company includes a number of M112 HIMAT systems as part of their organic support weapons, which may be attached to its component rifle platoons.