## 7 Scientific Issues and Deployment Implementation Routes
### The Key Technologies  
According to the above three key scientific issues to be solved, the following three key technologies should be adopted. 1. Information security modeling technology of networked ATM-CPS based on game theory. The cyber system and physical system of ATM-CPS seem to be independent of each other, but they are closely coupled with each other in the entire operation process. Because the standards and specifications of transmission protocols and communication interfaces used by each independent resource subsystem of the ATM are varied and not uniform, and the existing calculation models and communication models are quite different from the actual physical process models of the ATM-CPS, it is impossible to describe the information transmission flow among the various element nodes of the ATM system to quantify the interaction between the ATM cyber system and the physical system. Therefore, the ATM is abstractly mapped to CPS, and then the security of the ATM system is analyzed by using the CPS security theory. On the basis of analyzing the architecture and information flow of networked ATM system, the fine-grained CPS modeling of ATM is realized. The main tasks to be completed include:  
* Model the dynamic behavior of CPS under the normal operation and network attack of ATM system;
* Study the system parameters (detection rate, defense effect, physical interruption time, etc.) and attack parameters (attack intensity, attack duration, attack mode, etc.) that affect CPS security, accurately predict the performance of both players in the game, and reduce the impact on normal operation of ATM system in the game with attackers;
* Study the strategy selection of attackers and ATM system under different situations in the mutual game according to game theory and estimate the attack performance and detection probability according to the defensive and antagonistic parameters of ATM-CPS;
* Use the security evaluation algorithm to calculate the security indicators, such as mean-time-to-shutdown (MTTSD) and availability of ATM-CPS, and obtain an accurate evaluation of ATM-CPS security through the comprehensive evaluation of the indicator system;
2. Networked ATM information security situation awareness technology based on ATM-CPS game model. The information security situation of networked ATM system is the operation status and change trend of the entire network, which is composed of various system equipment operation conditions, network traffic behavior, aviation user behavior, and other factors. Various pieces of system equipment in the ATM are independent of each other and are connected through the network. However, after a certain aeronautical communication, the navigation, surveillance, and automation system equipment in the system is successfully attacked, and the threat can spread to other equipment connected to the equipment through the network (for example, ADS-B system networking; when one of the ADS-B systems is attacked, the attacker can use the ADS-B system as a springboard to attack ADS-B systems in other networks). This renders these devices subject to security threats. The networked ATM information security situational awareness technology based on CPS game model analyzes the impact of security threats (network intrusion, data tampering, and privacy leakage) and attacks (ADS-B counterfeit signals and Beidou navigation information deception) on the ATM system, which can accurately and comprehensively evaluate and predict the information security situation of the ATM. * Situation assessment. In the networked ATM system, various resource subsystem devices--all of which are data sensors used for receiving (collecting) and sending (transmitting) ATM business data--are distributed in different locations in a wide area and are connected by different communication protocols and interfaces to forma typical sensor network.