The Research And Implementation Of ADS-B Data Transmission Technology Based On Beidou RDSS

In recent years,China's civil aviation traffic and air traffic flow have continued to increase.Particularly,the flight activities have increased continuously and rapidly in low-altitude airspace,and the traditional surveillance technology cannot be comfortable with the rapid growth demand,so it is necessary to use a variety of surveillance technologies with exerting their respective advantages,complement each other,and realize the backup and supplement of surveillance technology to solve the issue of "insufficient surveillance" in low-altitude airspace,enhancing the surveillance service capabilities of general aviation.In order to realize the effective transmission of general aviation surveillance data from air to ground and meet the needs of air traffic controllers for the surveillance services of general aviation,therefore,automatic dependent surveillance-broadcast and Beidou RDSS(Radio Determination Satellite Service)short message technology are adopted.First of al,studying and analyzing the characteristics of the ADS-B(Automatic Dependence Surveillance-Broadcast)data link,the basic format and type of the message,and the transmitting process of updating message.As well as analyzing the principle of the short message communication of the Beidou Navigation Satellite System,the characteristics and service performance of the data link,and the data or command format of transmitting the short message.Then,it proposes to use the LZW compression algorithm to process the ADS-B data on the basis of the theoretical research and analysis,and to optimize the data transmitting process of Beidou short message by drawing lessons from the reliable algorithm of data transmitting.The data compression package that exceeds the maximum limit of the single data transmitting by the Beidou short message data link is sub-packetized,the sub-packet header control character is added,and the sender adds a timeout reissue process.Finally,the receiving terminal can complete the assembling operation according to the sub-packet header character,add the reissuing feedback of losing and the response of successful receiving,then complete the LZW decompression based on the complete compressed data to restore the original surveillance data,and the surveillance data achieve effectively transmitting on the data link of Beidou short message.Realize the LZW compression algorithm through MATLAB simulation,the simulating experiments test and analyze the consequent of data compression;then utilize the design and of ADS-B transmitter as well as the implementation of transmitting Beidou short message data,and finally verify the feasibility of the improved short message transmission process.The ADSB message can be transmitted on the 1090 ES data link,and the Beidou short message data link can be used to complete the transmission of air-ground data,providing positioning and surveillance services for general aviation activities.