Infantry Weapons Get Accuracy On-the-Move.

• Author: Ezell, Virginia Hart
• Position: Brief Article

The most fundamental job of a soldier is to be able to shoot, move and communicate. To shoot on the move is even better.

Although advanced combat vehicles have improved technology that enables shooting on the move, much of that technology has yet to migrate to smaller, lightweight vehicles. Expensive stabilized gun sights in larger vehicles help crews hit the targets at which they aim. Although recent missions have increased the possibility of engagements with small-caliber weapons, from 5.56 mm to 40 mm, soldiers still aim and shoot those weapons the old fashioned way.

Shooting from a moving vehicle looks easy, or so it seems in films and television productions. But hitting a target while shooting from a moving vehicle is difficult in real life.

Stress and other human factors associated with shooting influence accuracy in the still prone position at a firing range. These impediments can be corrected through training. But shooting on the move adds other physical inhibitors that cannot be overcome by training. The muzzle of a small-caliber weapon moves when the vehicle moves. Vibrations from the wheels traveling over the terrain make the weapon move. Without some kind of stabilizing force to keep the weapon on target as the shooter pulls the trigger, the bumps, jerks and swerves of a vehicle on the move prevent the shooter from hitting the target.

As the bullet leaves the muzzle, it may or may not travel on the intended trajectory to the target. Recently, engineers at the U.S. Army Research Laboratory (ARL) have discovered a way to fix that.

By adapting technology normally found in the turrets of Bradley fighting vehicles and Abrams tanks, ARL engineers improved the accuracy of small-caliber weapons mounted on small, lightweight vehicles to an almostprone position level. They call their invention the inertial reticle technology (IRT), a replacement sight adapted to the 5.56 x 45 mm M16A2 assault rifle and the .50 caliber M2 heavy barrel machine gun. They mounted the modified Ml6A2 on a fast-attack vehicle most often used by Special Forces units, and mounted the M2 on a high-mobility multipurpose wheeled vehicle (Humvee).

Instead of the traditional scopes, weapon sights and mounts, the IRT uses a video camera with a display unit mounted inside the vehicle and a lightweight "weapon positioner". The positioner "drives" the weapon to change elevation and azimuth. Sensors attached to the elevation and azimuth axes of the weapon measure the...