Research On 12mag FGS Catalog Construction And Algorithms

Image stabilization process of advanced space telescopes for future always contains fine guidance star suite to ensure the expected detection accuracy and stability of field of view.Fine guidance star suite is the key basis to determine the spatial absolute directivity of the telescope.The process of high-resolution,high-quality and high stability of the astronomical observation for future large-aperture space telescope,will need fine guidance star module which has high precision detection,high observation magnitude matching the field of view and the corresponding fine guidance star catalog.This paper focuses on the construction of fine guidance star catalog for fine guidance star suite which in the image stabilization process of space telescope.Firstly,this paper investigates the development and current situation of precision image stabilization system and fine guidance star suite of space telescope abroad,as well as the construction method of guide star catalog in our country.Secondly,research is done on a variety of commonly used star catalog characteristics,such as precision,band range and magnitude range,etc.UCAC4 star catalog is chosen as the basic star catalog for analysis and processing in this paper.Then,the overall design scheme is put forward,focusing on the 12 mag fine guidance star catalog construction.This paper mainly focuses on three parts: research on all-sky partition design and guide star storage for the goal of fast search of star in the field of view;research on guide star selection algorithms in order to achieve a good catalog uniformity and improve identification efficiency;research on star map recognition algorithms and design algorithm which is suitable for the hardware platform.The constructed fine guidance star catalog is well distributed,and the guide star search is fast.It can be used as a benchmark for star map recognition.In this paper,the construction process of fine guidance star catalog is designed according to the requirements of our project.Early exploratory research and feasibility verification of 12 mag fine-guidance-star catalog are made for fine guidance star suite on future large-aperture space telescope in orbit.The constructed 12 mag fine guidance star catalog lays a solid foundation to achieve large-aperture,high-resolution,high-quality and high-stability space telescope for engineering applications in the future.This topic contains three main innovations:Mixed partition and a data struction called k-d two-dimensional region tree are designed for the quick search of the guide star in the field of view.The speed of star search in the field of view reaches 5.32 ms.The whole guide star selection process is designed,including mixed partition magnitude filtering algorithm,star selection based on coefficient of variation and the blank field supplementation process.Star number in the catalog is selected from 1.14×108 to 3.53×106,the global uniformity of the guide star library reaches 0.43,and the local uniformity reaches 1.70,which is better than other guide star selection method studied before.Simulation results show that 98.33% in the field of view can be identified.Aiming at the high frequency requirement of fine guidance star,the SOM network algorithm is selected to be improved and applied to FPGA hardware platform.The star pattern recognition speed reaches millisecond order,laying the foundation for the future high speed attitude output in hardware implementation.Combined with star observing experiments,reaching <±4.7" matching accuracy,the feasibility of the constructed star catalog is also verified.