Bomb with a guidance system that directs its path toward a target.
It is steered by fins or wings on the bomb that move in response to guidance commands. Guidance systems may be electro-optical, laser, infrared, or inertial. Electro-optical systems send pictures of the area so that the bomb can be guided onto the target. Laser-guided bombs follow the reflections of a laser beam trained onto the target by an aircraft or a spotter on the ground. Infrared guidance responds to radiation generated by warm areas of the target. Inertial navigation is based on inputting coordinates derived from radar systems or from Global Positioning System satellites into the bomb's gyroscopes. Smart bombs, initially used in the Vietnam War, offer far greater accuracy than traditional gravity, or "dumb," bombs.