Localization Algorithm Based On Mds System With Synchronous Technology Research

Broadcast-automatic dependent surveillance (ADS-B) system based on Mode S mainly depends on Global Navigation Satellite System to obtain the position information of aircraft. The location information of aircraft in ADS-B system will be lost without GNSS information due to interference or other causes, and the reliability and validity of the position information can’t be guaranteed if the navigation services are provided solely by ADS-B system. Multi-point position dependent surveillance (MDS) system suatain downlink data link technology of ADS-B, and can receive ADS-B signal, and can deal with long-pulse signal, including the position information of ADS-B signal. The target can be located by MDS system, not to rely on other navigation devices, and the hardware compositon of base-station in MDS system with the ADS-B ground station are the same.Therefor, The MDS system based on ADS-B system can be realized, which is the expansion of ADS-B system function.This thesis looks at the the change of the future of the aviation field and introduces an powerful scene monitoring system which relying on a strong technology platform of ADS-B system, combined with multi-point position dependent surveillance technology. It focuses on research for the positioning algorithm, time synchronization technology and other key technologies, which are based on MDS system.Contents of this thesis include:1. An MDS system based on ADS-B is designed. Based on the compatibility between ADS-B system and MDS system, the expansion of MDS system function in the ADS-B system is cosidered, and a MDS system based on ADS-B system is designed, combined with ADS-B system under study.2. Position algorithms are studied and simulated. Several typical positioning algorithms are discussed and analysised. Because of their shortage, an improved positioning algorithm is proposed, of which the superiority of positioning performance is verified by the simulation.3. Time synchronization technology is researched. In order to meet requirement on the precision of time synchronization for MDS system, several time synchronization technology’s are focused on, and the method which can solve time synchronization problem of MDS system is studied by comparing and analyzing their advantages and disadvantages.4. The distribution way of base-staion is researched. Accord to the position error factor of MDS system, the distribution way of base-staion is studied, and the characteristic of positioning performance of system under some different distribution ways of base-staion is discussed by experiment, which can provide reference for the ditribution location of base-staion in MDS system.