Circular gratings are susceptible to factors such as engraving errors and installation eccentricity, preventing them from directly meeting the positioning accuracy requirements of high-precision angle measurement systems. Averaging data from multiple read heads can effectively self-calibrate the accuracy of circular gratings, thereby enhancing the precision of angle measurement systems. However, commercial servo control systems typically do not support real-time access to multi-read head signals on the same servo axis, making the online application of the equal division averaging method challenging. This paper explores the sampling, error compensation, real-time subdivision, and equal division averaging of multi-channel grating moire signals. A real-time processing system for multiple read heads was developed using an FPGA platform and applied to an angle measurement turntable. Experiments were designed to evaluate the stability of subdivision values, control resolution, angular positioning accuracy, and subdivision error, verifying the performance of the real-time multi-read head processing system. The system successfully enabled the online application of the equal division averaging method for multiple read heads, meeting the control resolution requirement of 0.005″ on a rotating test bench for angle measurement, achieving a positioning accuracy of 0.58″, and obtaining a repeatability of 0.06″ in positioning accuracy.