## 1 Introduction  
A star sensor is an instrument that determines the attitude of a vehicle in real time by means of an optical system, star point extraction, and star map recognition. It is one of the attitude sensors with the highest measurement accuracy [1]. Compared with solar and earth sensors, star sensors have a wider range of applications in the fields of navigation, aerospace, and aviation [2]. Therefore, star sensor technology has been at the forefront of international attention [3].  
With the development of the aerospace industry, the demand for high-precision and real-time star sensors is increasing day by day [4]. As the dynamic star simulator is the ground-test calibration equipment for star-sensitive instruments, the improvement of its star map display speed can improve the efficiency of star map identification by star sensors. In 2013, [PERSON], [PERSON] et al. [5] designed an electronic star simulator based on DSP (Digital Signal Processing) and FPGA (Field Programmable Gate Array) by utilizing a two-stage chain-list indexing approach to search for 9006 stars in the range of 0 Mv\(\sim\)6.5 Mv, and the average speed of a star map display was about 56 ms. In 2022, [PERSON], [PERSON] et al. [6] searched for 15,914 stars from \(-\)2.0 Mv to 7.0 Mv in a star map field of view of \(20^{\circ}\times 20^{\circ}\) using an externally tangent circular partition search algorithm, and a single star map showed an average velocity of about 9.43 ms. In 2021, [PERSON], [PERSON] et al. [7] used the navigational star leveling method to search for 5103 stars from 2.0 Mv to 6.0 Mv under a star chart field of view of \(10^{\circ}\times 10^{\circ}\). A star chart showed an average velocity of about 7.98 ms.  
Based on the current development of dynamic star simulators, it can be concluded that most of the dynamic star simulators are computers that transmit data directly to the star chart display module after performing three parts, namely, solving attitude data, searching for navigational stars, and coordinate transformation. On the one hand, the computer is large in size and high in power consumption, which is not convenient to test the star sensor at any time; on the other hand, if the computer adopts serial computing, then the instructions of the processor can only be executed sequentially, and only one instruction can be executed at most at a single moment. The DSP has the ability to perform high-speed computing [8], but it is not suitable for complex logic operations [9], and the code is cumbersome. The FPGA can be customized to meet the user's needs with the required modules [10] to reduce the cost and development difficulties [11].  
In recent years, in the context of the continuous development of dynamic star simulation technology, the refresh rate of the star chart has been a key indicator of the dynamic characteristics of dynamic star simulators. The higher the refresh rate of a star map, the less time it takes for the required star map to be calculated. As the ground calibration equipment of the star sensitizer, in the practical application of the star simulator, some experiments will need to be simulated outdoors. In outdoor environments, portability, miniaturization, and low-power systems are also among the current research trends. Aiming at the above problems of low real-time and slow calculation speed based on the serial structure of the dynamic star simulator chart display algorithm, this paper designs a dynamic star simulator star map display algorithm based on FPGA, which determines the position of the optical axis in the whole sky area by calculation on the FPGA platform and then displays the navigational stars within the field of view through coordinate transformation. The design of this paper improves the speed of the dynamic star chart display. It is significant for the development of miniaturization and the high real-time performance of dynamic star simulators.