This paper is concerned with the control strategy implementation for antenna servo systems. A linear active disturbance rejection controller (LADRC), which can estimate and compensate unmodeled dynamics and bounded disturbances in real time, is proposed. The field programmable gate array (FPGA) is utilized to design a control integrated circuit (IC). The procedure of achieving control objectives by FPGA-based IC and the relevant control algorithm are described in detail. Simulations and experiments are conducted to verify the effectiveness of our control strategy. It is shown that ADRC is an appropriate tool for handling uncertainties and disturbances. With the linear extended state observer and the feedback control law, tracking performance and disturbance rejection capability are greatly improved compared to a well-tuned PI controller.