This paper describes a real-time correlation tracker realized with field programmable gate array (FPGA). Primarily a method for correlation tracking target has been developed. The main point of this method is to present the reference pattern updating methods we implemented. Then, information on system hardware is given. The correlation tracking circuit is realized by FPGA so autotracker is small, low cost, and it could be used for real time application. Subsequently, system software can be found. System operation is controlled by high speed digital signal processor TMS320C30. In the end, the result of field-tests with our real-time correlation autotracker show that under complex background and foreground, such as clouds, trees, grasses, our approach can track a flying plane or a moving vehicle steadily.