Table of Content

24 June 2014, Volume 32 Issue 3

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Civil Aviation

Process design of general aviation synthetic operation support

WU Ren-biao,WANG Peng,WANG Xiao-liang

2014, 32(3):  1-5,19. 

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Low-altitude airspace is the main region of general aviation activity. As a solution to the absence of a clear process for supporting general aviation operation in China,a scheme for general aviation operation support process is proposed. The scheme is based on Opinions of deepening the reform of China's low-altitude
airspace management released by State Council and Central Military Commission. The scheme also considers the operating methods of both flight service station in U.S. and transport aviation in China. In the proposed scheme,flight process is split into several basic scenarios,which are combined for an actual flight. The scheme could provide a decision -making reference for the reform of low -altitude airspace and thedevelopment of general aviation in China.

Contruction algorithm of lateral navigation transition in flight management system

PANG Yin,ZHANG Wei-guo,LI Guang-wen

2014, 32(3):  6-10. 

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In the flight management system,the analysis of flight leg and the construction of transition path have to be realized based on the fight plan in order to obtain a proper path for horizontal navigation. The construction of transition involves the processing of two types of transition,standard leg transition and the special "fish-bird"transition. The present paper provides an analysis of the formation machanism of "fish-bird"path and proposes a judging method as well as a processing method. Based on this,a construction algorithm of transition between different types of legs is proposed,and the analyzing process of flight plan is produced. It is demostrated by the simulation that the proposed algorithm could effectively perform the leg analysis and construct the proper transition path.

Aircraft airworthiness requirements caused by increased operation altitude

JU Shi-chao

2014, 32(3):  11-14. 

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Technical obstacles of aircraft design caused by increased operation altitude are analyzed, as well as requirement changes of ventilation, cooling and pressurization of cabin, integrity of pressure chamber and oxygen equipments. Based on Advisory Circular(AC 25-20),Equivalent level of safety (TC6918SE-T-ES-5) and aircraft instances, regulations and some validation elements about cabin design are given.

RNP APCH vertical trajectory analysis based on QAR data

ZHU Yan,ZHANG Guang-ming

2014, 32(3):  15-19. 

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Accurate final vertical trajectory calculation is the basis of aircraft flight safety assessment. By using QAR data of flight operation to analyse vertical track of RNP APCH through Matlab,an method for the verification of accuracy and integrity of RNP APCH QAR data is proposed. Furthermore,the final nominal flight path of Navigation DataBase is reverted and the effect of pressure altitude error in RNP APCH operation is evaluated and analyzed. The conclusion meets the high-precision vertical track requirements of RNP APCH operation flight safety assessment.

Estimation of wet and contaminated runway landing distance based on multiple linear regression

GU Run-ping,WANG Peng

2014, 32(3):  20-22. 

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Estimation of landing distance on wet and contaminated runway is particularly important to ensure the safety of aircraft landing in actual operations. By applying multiple linear regression model,research is conducted on the landing distance estimation. Utilizing the least square to solve the equation of multiple linear regression firstly,and then using the"F test","t test"and"R test"to test the regression equation,finally,the theoretical formula is given to estimate the aircraft's landing distance on wet and contaminated runway. The results of simulation show that the method is effective and feasible.

Research of sector boundary demarcation based on weighted complexity Voronoi diagram

WANG Li-li,HU Jing,GAO Zheng

2014, 32(3):  23-26,30. 

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The controller workload is the main factor affecting the airspace capacity. To balance controller workload,reduce regulatory pressure and increase airspace capacity,a sector plan method based on weighted Voronoi diagram is proposed. This method is applied to determine the basic sector unit of the airspace sector,unlike the previous subjective measuring method,sector planning model is established based on complexity equalization principle,then using the growing algorithm to optimize combination of airspace sector units,ultimately the optimal sector boundary is found. And through the simulation of actual data in Xiamen low altitude controlled airspace,the results verify the rationality of the proposed sector boundary demarcation method.

Spectral momens estimation of airborne weather radar based on Capon

LU Xiao-guang

2014, 32(3):  27-30. 

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Airborne weather radar is a key equipment to detect the turbulence existing in flight path and is very important for aviation safety. The operation of airborne weather radar is mainly based on the estimation of first three spectral momens of radar echoes,including power,mean frequency and spectrum width. A covariance matrix model of the radar echoes is deduced from its Gaussian shape spectrum. And then the Capon method,which is used in line spectrum estimation,is employed to estimate the spectral momens. Finally,Monte Carlo simulations demonstrate the proposed method has a good performance even under low SNR.

Optimized station selection algorithm for DME/DME RNAV

SHEN Xiao-yun,CHU Shi-chao,JIAO Wei-dong,MENG Jian

2014, 32(3):  31-36. 

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Given the low accuracy and continuity caused by the frequent modification based on traditional DME/DME station selection algorithm,an avoiding frequently modifying automated DME/DME station selection algorithm of DME/DME RNAV route is proposed. By analyzing the coverage area of DME stations and calculating the effective area of DME/DME contiguous waypoints selected,the modification criterion is improved. Combining with area navigation requirements and the information of flight path and DME stations around,comparison and analysis with traditional algorithm is performed using the Matlab models of DME/DME station selection. And then the performance of DME/DME (selected)RNAV is estimated. Finally,based on the information of A593,some simulation experiments are performed. The simulation results show that the algorithm selects a pair of more reasonable DME,and the algorithm can satisfy the requirements of the DME/DME RNAV performance,meanwhile the stability of the algorithm can be improved.

Novel virtual maintenance environment layout planning research based on GA

ZHANG Zhong-hua,GENG Hong

2014, 32(3):  37-40. 

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Virtual maintenance environment is the workplace of virtual repair disassembly and assembly,which is an important part of maintenance virtual realization. During the maintenance disassembly process,conditions such as complex disassemble parts and excessive disassembling parts appear frequently. In order to achieve ideal display performance and resolve 3D layout problems of virtual maintenance disassembly parts and components,level dividing is applied to classify the parts and components;3D spaces are simplified into multiple 2D layouts,reducing layout complexity. Genetic algorithm is used in 2D layout to optimize and improve the quality of layout.Finally this method is employed into virtual disassembly parts and components layout of aero-engine high pressure compressor and is verified feasible.

Research of aero-engine fault diagnosis method based on monitoring of twin differences

CAO Hui-ling,PANG Si-kai,XUE Peng,HUANG Le-teng,QU Chun-gang

2014, 32(3):  41-44,58. 

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Aero-engine fault diagnosis based on gas line parameters is a simple,economical,effective and practical fault diagnosis method. But since the engine baseline hidden in the monitoring system of the engine manufacturer,and it is not available to users,so self-monitoring and diagnosis for users is limited. Starting from the concept of baseline,a method based on monitoring of twin differences is raised to achieve fault diagnosis with differences between the two engines on one plane instead of the deviation between actual data and baseline values. QAR (quick access recorder)as a widely used data access system at present provides accurate and valid data to support aero-engine fault diagnosis.

Engineering and Technology

Construction of next generation TypeX message system for China civil aviation

YU Ming-liang,LI Yong-jin

2014, 32(3):  45-49. 

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A solution of TypeX message system used to promote information technology development of China air travel and tourism industry is proposed,filling the vacancy of China civil aviation TypeX message system. TypeB message is widely used to transport the non-real-time reliable information in civil aviation industry;however,it has been faced with upgradation due to defects such as limited message length,inextensible content and so on. Taking full advantage of the extensible characteristics of TypeX message,the life cycle management of TypeX message is accomplished and message looping is prevented;by borrowing the idea of the session from TCP/IP protocol,the reliable method to transfer TypeX message is obtained;by summing-up the error types of TypeB message,the method to deal with the most of TypeX message errors is found. The TypeX message system makes the information interaction between civil aviation IT systems more varied and more reliable,providing more flexible and safer types of access,and proving its broad prospect in airlines,airports and GDS.

Anomaly detection technique oriented to TCP flow

JIAO Wen-huan,FENG Xing-jie

2014, 32(3):  50-54. 

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In order to solve the problem that network-flow anomaly detection cannot distinguish between mutations in normal and abnormal traffic flow,an anomaly detection technique oriented to TCP flow is presented. Using method of summary data structure,this model calculates the Hurst parameter and TCP packet integrity to discover the network anomalies. Not only can it achieve a summary of large-scale data storage to improve the efficiency,but also realize the purpose to distinguish between the burst traffic with abnormal tratfic flow.Experimental results show that this method has high detection rate and low false detection rate,it can be better used in network anomaly detection.

Civil Aviation Management

Evaluation of airport aviation security based on combined weight

LI Long-hai,LIU Fan

2014, 32(3):  55-58. 

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As a vital part of civil aviation security, the evaluation of aviation security system is a practical measure to improve airport security level. However, it is difficult to evaluate aviation security in a scientific and objective way. Combining with AHP and entropy method, combined weight synthesizes the weights by multiplication
normalization method and uses compatibility degree to test the results. An empirical study of an aviation security system is conducted to illustrate how it works and validate that "management"and "personnel"are the emphases of which. Unlike AHP or entropy method, the evaluate results of combined weight are objective and reasonable.

Basic Science

Self-adaptive algorithm for variational inequalities

HE Song-nian,LUO Biao

2014, 32(3):  59-61. 

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A self-adaptive algorithm is proposed to solve the Lipschitz and strongly monotone variational inequality defined on a closed convex subset in a real Hilbert space. Since this method selects stepsizes via a selfadaptive way,i.e.,has no need to estimate the Lipschitz constant and strong monotone coefficient,its implementation is rather easy. Strong convergence of the algorithm is proved.

Further results on uniqueness of meromorphic functions and differential monomial sharing two values

SHI Xin-hua

2014, 32(3):  62-64. 

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Nevanlinna distribution theory is used to study the uniqueness problems of differential monomial of meromorphic functions that share two values,the results improves some previous ones.