Research And Application Of The Reliable Technologies In Air Traffic Control System

The Air Traffic Control (ATC) system requires high real time ability as well as high reliability. The service provided by the ATC system must not be interrupted, so reliability requirement is especially needed to be met. Based on these characteristics of ATC system, and on the basis of the research work in the WiseSoft Ltd. in Sichuan University, the author has done a great deal of deep and delicate researches on some key technologies in monitor and control subsystem of ATC system. All the researches are related to the reliability of ATC system. The main problems this thesis intends to explore are just below: Design and application of the dual redundancy backup system:Compared to the former backup system, the ATC system have high require on real time. the mechanism of positively detecting the managed process is added to the management process. This mechanism with the combination for time limit of the former system, the new one does the shifts of major and minor machines more accurately and then makes the system more reliable. In addition, due to the complexity and variety of the process in ATC system, an idea of prior managed process is put forward and a prior judging algorithm is designed. Through investigating and studying, the algorithm has been proved feasible. Di-LAN redundancy technology and its application:Di-LAN redundancy guarantees the quality of network communication. In this system two physical independence networks are applied. When one is down, the other is able to substitute the former one. Di-LAN redundancy mainly including hardware configuration, work models, LAN switch, diagnosis and location of fault, etc. Research on SNMP V3:Monitor and control subsystem is to supervise the working status of the system, radar interface, flight data process interface and so on. It is the guarantee of the normal operation of the whole system. Monitor and control subsystem nowadays is based on SNMPv2. Because there is hidden danger in SNMPv2 protocol and the interface to the outside is provided by subsystem, the internet safety is threatened in ATC system. SNMP V3 would make SNMP management safe by using User-based security model. Based on the structure of SNMPv3 system, the thesis would explore the reliability of this system from two aspects: USM (user-based security model) and VACM (view-based Access control model). The dual redundancy backup system and Di-LAN redundancy system have been employed in some ATC system project. And satisfactory results have been received from users. According to the emulation test, System information can be got from the proxy access of SNMPv3 in the monitor and control subsystem. With the analysis of influence to network system performance brought from additional expense by SNMPv3 safety, this paper get the conclusion that the influence of SNMPv3 safety system, especially when encrypted, to the whole system mainly lies in the aspect of dealing with charge increase of processor while the influence to community link is minor.