SACLOS

SACLOS, or Semi-Automatic Command to Line of Sight, is a missile guidance method used in some anti-tank guided missiles and other remotely guided weapons. In SACLOS guidance, the operator keeps the target within the aiming sight, and the weapon’s onboard guidance system automatically generates steering commands to the missile to maintain the line of sight to the target. The result is that the operator only has to track the target, not steer the missile.

Guidance signals are typically transmitted via a two-axis command link, encoding the angular error between the line of sight and the actual missile trajectory. The launcher or a remote firing unit processes the target position and sends azimuth and elevation corrections to the missile’s autopilot, which adjusts the flight path accordingly. The command link can use radio frequency or, in some systems, fiber-optic connections; several designs incorporate video or optical feedback for accuracy.

Advantages of SACLOS include reduced operator workload and improved hit probability at longer ranges compared with manual MCLOS guidance. It also allows a missile to be guided against more maneuverable targets, as the autopilot handles most steering.

Limitations include dependency on continuous line of sight to the target, vulnerability to smoke, dust, or countermeasures that obscure the target, and potential susceptibility to jamming of the command link. It is not fire-and-forget, and engagement after launch depends on maintaining tracking until impact.

Notable SACLOS-guided systems include the BGM-71 TOW and the MILAN family of anti-tank missiles.