| In recent years,China has started the development of civil aviation large aircraft with independent intellectual property rights,and has achieved certain results.However,many equipments on board still use foreign equipments,including Airborne Tronsponder equipment.The imported equipment is generally expensive and relatively difficult to maintain.In order to break the monopoly of foreign countries on the market of Airborne Tronsponder,it is imperative to develop the new type of S mode Airborne Tronsponder equipment.This thesis based on the DO-181 E standard,starting from the angle of airborne transponder,analysed the format of interrogation and reply signal of ATCRBS/S mode transponder.In addition,this thesis analysed the ground-to-air data link and air-to-air data link protocol of airborne transponder in-depth,studied the data error protection and checking algorithm.The data field format and protocol connotation of S mode was analysed.By the use of C++ Builder software platform,the thesis realized the function of airborne transponder data protocol.The main work is as follows:1.The thesis studied 8 kinds of interrogation and reply signal formats,including the interrogation signal of A mode query,C mode,A/C/S mode,A mode only,C mode only and the reply signal of A/C mode,the interrogation and reply signal of S mode.The 15 kinds of data formats that been used in the S mode data link are analyzed now.Then it summarized the protocol functions of each data format.It focuses on data error protection,data validation,correction and error correction algorithm in S mode,and describes in detail the generation process of uplink and downlink Address Parity and Parity/Interrogator fields in S mode.2.The thesis described the five classes of S mode airborne transponder divided by function.Based on the DO-181 E standard,the data format and protocol of the airborne transponder are analysed.The data format analysis focuses on the high field coding algorithm,4096 identity coding,downlink request coding,flight state FS coding and so on.Detailed analysis of the S mode of query and accept protocol,all call locking protocol,Flight Status protocol,Vertical Status protocol,Utility Message protocol,Comm-A protocol,Comm-B protocol,ELM protocol and other ground-to-air data link protocol and air-to-air data link protocol including Comm-U/V protocol are presented.3.By using C++ Builder software platform,made three software terminals including airborne transponder,interrogator,and TCAS.The transponder assisted by interrogator and TCAS completed the simulation of data protocol of level 4 transponder,and realized the data protocol of ATCRBS/S mode airborne transponder based on DO-181 E standard.This data protocol include the error protection protocol,interrogation acceptance protocol,all-call reply protocol,lockout protocol,Flight Status protocol,Vertical Status protocol,Utility Message protocol,Comm-A/B protocol,ELM protocol and Comm-U/V protocol.Combined with the software simulation results,the correctness of the analysis of data protocol of airborne transponder is tested and verified. |
