Research On Automatic Control Technology Of Two-Dimensional Star-Following System

In order to investigate the impact of the atmosphere on laser transmission,astronomical observation,and optoelectronic engineering,it is necessary to measure and study the atmospheric optical characteristic parameters.There are currently various measurement methods and forms available,among which the method of using a ground-based two-dimensional tracking star system to track stars for measurement has been widely applied.Different atmospheric optical parameters,such as atmospheric coherence length,atmospheric transmittance,and water vapor content,can be obtained through different calculation methods.In the existing measurement process,due to the low degree of automation of the instrument,there are still many manual operation steps,such as manual leveling and manual positioning,which affect the measurement efficiency and accuracy.With the continuous improvement of software and hardware conditions,there is significant room for improvement in the automation level of the two-dimensional tracking star system.Research and implementation of this system can further improve its working efficiency and stability.In this paper,we conduct research on the hardware structure,system composition,image processing,and automation algorithms,and design and implement a two-dimensional tracking star system with high automation degree.The main research contents are as follows:1.In terms of hardware for the instrument,the overall structure of the optimization device hardware is improved,and automation enhancements are made to various functional modules during the design phase.For the required automation functionalities of the device,the hardware structures of the rotating platform module,focusing module,leveling module,main control system,and imaging system are upgraded and improved.This includes the addition of drivers,sensors,and control units necessary for automation control.Additionally,a detailed introduction is provided regarding the selection and technical specifications of each functional module of the device.2.In terms of image processing,improvements are made to address the low efficiency of image processing and poor recognition stability of traditional devices.In order to meet the needs of different usage scenarios,processing flows for uniform background and non-uniform background are provided.The elimination of different backgrounds is achieved using the region mean representation method and morphological calculation method.For the imaging characteristics of the star beacon,the contour extraction method is used to mask the details inside the light spot,achieving fast detection.An adaptive partition algorithm for images is proposed,which can dynamically update the partition position and fluctuation threshold.This algorithm reduces computational complexity while maintaining good tracking and identification stability.Experimental results show that the optimized method improves processing efficiency significantly compared to traditional methods.3.In terms of automation control,the non-automated processes that exist in the traditional devices for instrument leveling and positioning,star switching and tracking,image focusing and exposure are optimized.An upper computer star chart data system was developed,and a stable automatic switching star function was implemented by designing a star tracking trajectory algorithm.Stable identification under different sky brightness backgrounds was achieved by automatically updating the exposure value and recognition threshold.An automatic correction function was achieved by using the accumulated value of star imaging offset and timely correction through image computation.The system’s automatic leveling function was achieved through angle sensors and screw stepper motors.The initial positioning process of the system was simplified using the extended field algorithm,and automatic star positioning was achieved in conjunction with an electronic compass.Additionally,this method can also be used for star switching.A focusing evaluation algorithm suitable for star imaging was proposed,and an automatic focusing function was achieved using a hill-climbing algorithm with elastic intervals and thresholds.The automated two-dimensional star tracking system was utilized to conduct continuous tracking experiments during day and night,along with measurements of atmospheric coherence length.Multiple automatic control techniques were employed in the experiment.Ultimately,the system successfully completed a 24-hour continuous tracking task and collected measurement data.The system achieved stable tracking of a single star for over 10 hours.The continuous recognition results and correct data trends provided additional evidence of the reliability and practical significance of the automatic control technology.