Line-of-sight (LOS) stabilization systems form part of modern surveillance and fire control systems (FCSs). Conventional controller designs are dependent on the accuracy of the mathematical model of the plant, which usually ignore high order dynamics. Further, plants are linearized around the operating point. Although robust controllers can be designed to overcome uncertainties in plant parameters as well as nonlinearities, the resultant controller becomes complex for implementation. Fuzzy-knowledge-based controller (FKBC) design presents a good methodology to overcome above difficulties. A fuzzy control system is implemented to control inertial rate of LOS. We present the design and implementation aspects of this particular FKBC and the performance achieved with respect to the performance achieved using a conventional controller.