| On November,2010, the state council and Central Military Commission issued "views on deepening reform of low-altitude airspace management", which put the opening-up of low-altitude airspace on agenda. With the opening-up of it, vigorous development of general aviation posed new challenges to the current surveillance methods. To provide low-altitude airspace with a proper surveillance method was the main objective of this paper.This paper was to elaborate the contradiction between the opening-up of low-altitude and immature surveillance method. Before going to establish and improve low-altitude surveillance system with the National Conditions. It was necessary to analyze the features of radar surveillance, MLAT and ADS, and then to choose the proper surveillance for the low-altitude airspace based on the advantages and disadvantages of various surveillance technologies.Radar surveillance technology was the one which was most widely used in the world, but it is difficult to promote the use of it for the surveillance results was not satisfactory and the cost was too high. Now, The internationally recommended approach to provide surveillance services in low-altitude airspace were ADS-B and MLAT. The third chapter focused on the analysis of the principle and data link of ADS-B surveillance system. Using three kinds of evaluation system, the AMCP/5, RTCA MASPS and TLAT, to assess the three data links of ADS-B, Chapter Four analyzed the Malt's positioning principles, methods, positioning precision assessment. Specially presented a thorough study of the relation between number and layout of base stations and height of the surveillance airspace, and put forward a surveillance method based on the mobile station locating method for special airspace which not needed high precision result.Because it will take some time to fully apply technology of ADS-B and MLAT.In the fifth chapter the author proposed an auxiliary airspace surveillance system based on the aviation digital map. The system can be used in the airspace where are absence of existing technology to provide surveillance service, it also can be a complement for other surveillance technology in the transition phase. |
