Implementation of star centroid extraction based on FPGA

Abstract

Star tracker is a high-precision attitude sensor that obtains carrier attitude information by processing star images, and star centroid extraction is an important step in the work of star tracker. This paper proposes a star centroid extraction algorithm based on Field Programmable Gate Array (FPGA), which consists of six parts: threshold segmentation, 3X3 matrix generation, pixel weight calculation, connected component labeling, star centroid weight summation, and divider IP core. In order to verify the accuracy of FPGA centroid extraction algorithm, three sets of experiments were conducted. Firstly, generate a noise-free simulated star image, and compare the extraction result which was done on the ModelSim platform with the setting real values to analyze the FPGA centroid extraction accuracy under ideal situation. Secondly, Gaussian noise was added to the simulated star image, and analyzed the FPGA extraction accuracy under noisy situation. Finally, a real star image is extracted on Matlab and ModelSim, respectively, and take the Matlab extraction result as a reference value to evaluate the FPGA extraction accuracy. Simulation and experimental results show that the proposed algorithm has high extraction accuracy ,which can meet the working requirements of star tracker.