Research Of Heterogeneous Control Systems For Large Telescopes

Control system based on modern computer technology and electronic technology is one of the important components in large telescopes. The adoption of control systems in the1970s advanced telescope technology to break aperture limitations and bring leaps to observation abilities. With the application of automatic control technology in telescopes, more and more devices need computer domination to perform accurate control, and hence control system has become a necessary part in large telescopes.Currently astronomical technology has entered a flourishing new era. And in all optical, radio and space telescopes over the world, there is a common trend toward increasing aperture, scale, complexity, and device diversity, etc. Control system that serves telescope observations should correspondingly supply flexibility, extensibility, real time, distribution and cross platform ability to meet the needs. In recent years, China has already or planned to build several large telescopes including LAMOST telescope with the highest spectrum acquiring rate in the world, and FAST telescope which would be the world’s largest radio telescope. Meanwhile due to lack of large telescope construction experience, our research on control systems still stays in the beginning stage. With increasing national investment on large scientific facilities, more and more large telescopes will be enrolled into construction plan. Therefore research on control systems become an urgent need, and based on such background, the thesis carried out studies on large telescope control systems.The thesis first introduced the development process of astronomical telescopes, discussed typical telescopes in optical, radio and space area, reviewed the situation of domestic large telescopes, and brought out the idea of telescope control system.Then we gave an analysis to the control system of modern telescopes. Considering the huge data rate and complex characteristics of large telescopes, we summarized the basic features that control system should supply. After a review of current control systems for the world’s main telescopes, we brought out the orthogonal layered control system architecture.The distributed message mechanism for telescope control was studied. Communication between subsystems is a key aspect of telescope control because of their high data rate and numerous control variables during observations. This thesis discussed several technologies like AMI/AMH, notification service based Message Bus and Data Distribution Service. After experimental test we discussed the characteristics of different technologies and their application situation.Then the thesis studied the architecture of central control system. Components of system service layer, core component layer, user interface layer and subsystem agent layer are briefly discussed according to the layered concept. Design of major threads in the orthogonal architecture including commanding thread, status thread, alarming thread and logging thread are given.The control of subsystems is realized basing on the adaptor pattern. Aiming at common subsystem structures and taking subsystems of LAMOST and FAST as examples, designs are given for different types of subsystems including EPICS-based, CORBA-based and socket based architectures.Finally the thesis presented several practical implements of control system architecture. We gave LAMOST Observatory Control System, LAMOST CCD system Master Control and FAST Central Control System as our main development results, and from practice result we verified the usability of our architecture.Generally, this thesis studied the heterogeneous control system for large telescopes and provided a flex, extensible, distributed, real time and cross platform control system architecture. The main innovations of this thesis are:(1) Investigated main large telescopes of the world and analyzed their characteristics and requirements, summarized the similarities of their control systems and then brought out the orthogonal layered control system architecture.(2) Respectively studied central control system and subsystem control for large telescopes. Discussed the main components according to layered structure, and designed major threads according to orthogonal architecture; designed control for subsystems based on adaptor pattern, and implemented corresponding subsystem controls for EPICS, CORBA and socket based structures.(3) For the first time applied the architecture to two of the national telescopes, and implemented LAMOST Observatory Control System, CCD system Master Control, FAST Central Control System and Active Reflector Control System. Through development and observation practice, system availability is validated.