The M712 Copperhead projectile was the first smart artillery round ever developed. Its accuracy is measured in centimeters, and its lethality is impressive. Copperhead is a cannon-launched, 155mm artillery projectile which guides itself to a laser-designated target. The munition is capable of defeating both armor and point targets at ranges of over six kilometers, and provides the battlefield commander with the unparalleled capability of utilizing artillery to the same effect as direct fire weapons and close air support. The system was employed during Operation Desert Storm, during which it met with great success. Copperhead projectiles were used to destroy observation and border guard posts and forward radar installations during the first week of artillery attacks.
The cannon-launched guided projectile (CLGP) M712 (Copperhead) is a 155-mm, separate-loading, laser-guided, HE projectile. It is heavier (137.6 pounds) and longer (54 inches) than the standard 155-mm projectile. The M712 projectile consists of three main sections: a guidance section (forward), warhead section (center), and control section (rear). The guidance section contains the seeker head assembly and the electronics assembly. The nose of the projectile houses a laser seeker in a plastic cone. The warhead section contains an HE antitank warhead consisting of 14.75 pounds of composition B. The control section includes the fins and wings that deploy in flight and allow the round limited maneuverability.
The trajectory of the Copperhead projectile is similar to that of a conventional round. Only when the projectile reaches a point on the descending branch of the trajectory does it differ. At that point, on the basis of the two-digit timer setting included in the fire commands, the guidance and control systems are activated. This enables the projectile to alter the remainder of its trajectory.
At 20 seconds from impact, the laser designator operator begins designating the target. The ground laser operator may use a G/VLLD, a laser target designator (LTD), or modular universal laser equipment (MULE). Airborne systems include the AH-64, OH-58D, and unmanned aerial vehicles. The Copperhead projectile acquires the reflected laser energy and initiates internal guidance and control, allowing it to maneuver to the target.
The ground surface area in which the round can maneuver is limited. The optimum limits of maneuverability of the Copperhead round is called a footprint. The size of the footprint is determined by the range and the shape of the trajectory, but it can also be affected by cloud height. The ballistic aimpoint is usually short of the target location sent by the laser designator operator. The distance that the ballistic aimpoint is short of the target location varies and is called the offset correction. This offset distance is used to ensure that the maximum probability of hit occurs at the original target location sent by the observer. The larger the target location error, the lower the probability of hitting the target.