A control system (102) operates within a dynamic range, and a follow-up
system (104) is commanded to reduce a positional error between the follow-up
system and the control system when the dynamic range is exceeded. A linear follow-up
command may be initially provided once a dead band value (208) is exceeded.
The follow-up system (104) is driven relative to its base mount (103)
in a direction to reduce the positional error to within a null value range (214).
The follow-up command may also implement a decay function to control the follow-up
system (104). A control variable transfer function may also be utilized
to gradually subtract the dead band value from the follow-up system position error
command as a function of time. The decaying function may include linear as well
as non-linear decaying functions. In one embodiment, a figure eight-type hysteresis
control function may be implemented to control the inertial position of an inertial
element. The various embodiments of the present invention may be suitable for space-based
laser designating and targeting systems, space-based camera-positioning systems,
space-based telescopes, and radar antenna positioning systems.