Command guidance is a means for controlling a precision-guided munition that has no onboard guidance. It can be "man-in-the loop", as with the BGM-71 TOW antitank missile, which trails a wire or fiber over which a human operator directs its path. Alternatively, the commands can be sent by a radio data link, as with the Fritz-X World War II anti-shipping missile.
Command guidance is very much like beam riding guidance, where the missile stays centered in a radar beam that is tracking the target.
The most modern applications of command guidance involve missiles that can make no course changes on their own, but do have a forward-looking infrared, television, or other imaging sensor whose images are sent back to the operator.