The Research Of Evaluation Of The Civil Airport Clearance Based On GIS

Along with the sustaining growth of Chinese economy, air-transportation is developing rapidly, and the step of the civil airports construction is speeding up unceasingly. By the end of 2010, the number of civil airports in Chinese mainland has achieved 175. During the twelfth"Five-year-plan",many civil airports planning and construction projects are still listed in the national development plans. While in the airport construction planning and regular management, it is necessary to evaluate civil airport clearance, guarantee its well-condition, and make sure satisfy the need of flight safety. The airport clearance zone refers to a certain zone along the taking off and landing route nearby the airport. Specifically,it is an air zone above both the ends and the sides of the runway and it is used for visual circling,taking off, climbing and landing of airplanes, and is established to control the height of obstacles around the airport.According to the definitions of obstacle limit surfaces in "Technical standards for airfield area of civil airports", a mathematics equation of obstacles limit surfaces of precise approach runway was deduced, of which the airfield indicator is 3 or 4, and the clearance evaluation coordinates was established. In addition, this thesis provides the evaluation scope of each limit surface based on principle of the lowest plane controlling when the restricted height is calculated. Furthermore, the calculation method of the obstacles′coordinate in clearance evaluation coordinate is deduced from the spherical triangle cosines theorem on condition that the geographic coordinates of landing threshold and obstacles are known.Certain feeder airport located in southwest of China was used as an example. The airport clearance zone was digitalized in Super Map Desk Pro5.2, and the limit surface's data set and the obstacles data set were established in GIS. Airport clearance visualization management based on GIS was realized through superposing the different layers, which improved the efficiency of airport clearance materials management. By the end of this thesis, the height of the obstacles around the airport in 15km from the ARP was estimated. It was proved that this method may change the present pattern of airports clearance estimation, with which computed data correctly.