Table of Content

25 February 2019, Volume 37 Issue 1

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Civil Aviation

Reacquisition time and positioning accuracy of airborne BDS receiver

NI Yude, MA Yuanchen, ZHANG Xinyi, LIU Peng

2019, 37(1):  1-6. 

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As the top end user of airborne BDS receiver, civil aviation requires more exacting performance. Performance indicators of airborne BDS receiver affected by dynamic environments include reacquisition time, positioning accuracy and so on. In dynamic environment, the above two performance indicators are studied and simulated,analyzing affecting parameters of them, as well as the relationship between the two indicators and relative parameters. Under high speed and high acceleration environment, the reacquisition time and positioning accuracy of airborne BDS receiver are analyzed and simulated based on actual flight data. Results show that the reacquisition time of airborne BDS receiver is affected by parameters such as carrier-to-noise ratio and lockout time, and increases with the increment of aircraft speed. Influencing factors of positioning accuracy include loop noise bandwidth, carrier-to-noise ratio and acceleration, among which the increment of aircraft acceleration causes degrading positioning accuracy ofairborne BDS receiver.

Construction and characteristics analyses of ATC sector complex network

WANG Xinglong,GAO Jingdong, ZHAO Mo

2019, 37(1):  7-11. 

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ATC system is the critical guarantee for operating security and efficiency of air transportation. As the smallest units of ATC, control sectors are crucial to safe, smooth and orderly aircrafts running. Employing complex network, control sectors network is established, considering sectors in a scale of airspace as nodes, linking the nodes if flights go directly from one to the other. Correspondingly, degree, strength, average shortest path length,clustering coefficient and betweenness of the sectors network are defined. By instance analysis of a scale of airspace locating in Central and Southern China, the degree distribution is pretty homogeneous, which is different from strength and betweenness whose distribution follows exponential functions. Degree has an influence on other metrics, while strength does not show it. Result indicates that assortativity is another property of the sector network as well.

Multi-protection technique of power supply system for C919

XUE Jianliang, GE Hongjuan, XU Yusong, ZHANG Lu

2019, 37(1):  12-16. 

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To meet the high reliability requirement of power supply system for C919 airplane flight test equipment, a multiple protection scheme for the system is proposed basing on three-channel hierarchical power supply and redundant power supply. The multi-protection circuits have been designed and developed including over temperature protection circuit, input over-voltage and under-voltage protection circuit, output over-voltage and under-voltage protection circuit, output ripple voltage protection circuit, output overcurrent protection circuit and cooling fan stall protection circuit. The ripple protection circuit basing on infinite gain multiple negative feedback second-order high-pass filter and the cooling fan stall protection circuit basing on presettable synchronous/asynchronous down counters CD40103 are analyzed in details. Simulation and experimental tests prove that once the input voltage, output voltage and overload capacity exceed the design limits, the current scheme is capable to protect the power supply system, which is consistent to its designed performance indices.

Safety risk management evaluation of aviation maintenance engineering outsourcing contractors

GAO Yang, YU Qingpeng

2019, 37(1):  17-21. 

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A safety risk management evaluation index system of maintenance engineering management outsourcing contractors is established based on analysis of related regulations and manuals, expert interview, questionnaire and other methods. The corresponding evaluation model is also established. Combinated weighting method employing AHP and entropy weight method is adopted, correlation degree among safety risk management evaluation indices of contractors is calculated, and the safety risk management levels of contractors are obtained.Finally, model verification is carried out. Result shows that the index system and evaluation model are suitable for evaluating safety risk management of contractors, providing reference for engineering operation.

Rapid response support of domestic airplane manufacturer based on ACARS real-time monitoring

YAN Zhenqian, SUN Wei, HUANG Aijun, CHEN Xinxia

2019, 37(1):  22-26. 

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With the aid supplied by the rapid response organization of its customer service department, the manufacturer can provide 7 ×24 hours all -weather service to receive and resolve customers爷requests after aircraft delivery,providing timely and effective technical support for customers to realize smooth flight operation. Through analysis on ACARS report data, engineers can timely obtain the important operational information and monitor real-time technical status of airplanes, helping airlines to isolate the fault and arrange maintenance schedule in time. In this way, airlines can find the fault quickly, get the information actively, and schedule resources timely, in order to reduce flight delay or cancellation. The combinated application of ACARS monitoring and rapid response support provides reference for domestic civil aircraft operation support.

Comparative analysis on taxiway system planning at heavy traffic airports in China and USA: A case between PVG and ATL

TANG Xiaowei, LIU Lujiang, SUN Fanrong, CHENG Binghe

2019, 37(1):  27-33. 

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As representatives of busiest airports in China and USA, PVG and ATL are highly similar in runway configuration. They both have two groups of closely spaced parallel runways, but ATL has obvious advantages in taxiing efficiency. Based on the layout of the two airports, main differences in planning and design of taxiway system and their impacts on ground operation are analyzed, providing suggestions for the reconstruction,expansion or new construction of large and medium-sized airports in China. Comparative analysis shows that there are four main factors relating to the difference in ground operation efficiency: taking-off waiting area, endaround taxiway, vertical linking taxiway and rapid exit taxiway.

Review factor and compiling specification of RFM performance chapter

LIN Yi, GE Hongjuan, HU Mengjun, ZHANG Lu, ZHAO Quan

2019, 37(1):  34-38，45. 

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Performance chapter of transporting RFM is researched, recommended compliance verification method and compliance inspection factors of the regulation are analyzes and proposed basing on detailed explanation of CCAR29.1587 Performance Information. Take AC29.1587 and relevant chapters of RFMs such as AC313，BK117-C2, A109S and S-76C as reference, some requirements are proposed to make the RFM performance chapter meet the standard of CCAR29.1587, putting forward writing specifications from the aspects of structure,content and format, helping improve the preciseness and normalization of RFM compilation in China.

Engineering and Technology

MS tracking algorithm based on block color histogram

ZHANG Hongying, WANG Sainan, HU Wenbo

2019, 37(1):  39-45. 

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Aiming at the problem of object occlusion in complex scenes, an improved tracking algorithm based on block color histogram and MS is proposed. First, in order to obtain strong ability to express local features, block color histogram is utilized. The target is divided into several regions to color features. Then a confidence map generating method of the block color histogram is proposed, helping MS algorithm search the best target area in the iteration of confidence map. Experimental results prove that the proposed algorithm can keep tracking the target continuously and accurately even though the target is occluded, which improves the robustness of the algorithm compared with traditional MS tracking algorithm.

Buckling analysis on stiffened composite structure

GUO Qiaorong, ZHANG Xifeng, ZHU Xiaohong

2019, 37(1):  46-49. 

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A finite element model of stiffened composite structure is established with ABAQUS. The buckling behavior is analyzed by the Linear Eigenvalue Method under axial compression. The critical buckling loads are computed using the modes. The buckling loading capabilities are affected by various factors, which include stiffener parameters, panel parameters and boundary conditions. Simulation result shows that the buckling loads are obviously affected by the height and numbers of stiffeners, the thickness and sequence of panel layers, and the boundary conditions.

Influence of boundary effect on bending moment of pavement slab under circular load

QI Chunxiang, LI Yao

2019, 37(1):  50-54，59. 

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In order to make a better use of the finite element software ABAQUS for simulating pavement slab problem considering boundary effect, the theoretical reference of model size is offered. The influence of boundary effect on bending moment of pavement slab under circular load is simulated by using ABAQUS. Side length of square concrete slab model is constantly changed, and the radial unit length bending moments of load center are respectively calculated. Meanwhile, analytical solution is calculated according to the expression of radial unit length bending moment of axisymmetric circular load acting on infinite plate based on Winkler foundation model,then curves of analytical solution and numerical solution are compared. It is found that the most inappropriate and the most appropriate side length of model are linear with radius of relative rigidity, having a power function with diameter of load. Eventually, the side length expression of concrete slab model is obtained based on diameter of load and radius of relative stiffness, providing reference for finite element modeling.

Identity-based certificateless bilinear pairing key agreement scheme

GU Zhaojun, LIU Dongnan

2019, 37(1):  55-59. 

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In order to solve the problem that IDAK protocol does not have forward security and the improved IDAK protocol does not satisfy all security attributes in key agreement phase, a bilinear pairing technique is used to propose a certificateless and no-hosting key agreement scheme with PKG forward security. This key agreement protocol is applied to specific civil aviation system simulation for the first time. Experiments prove that the scheme has reasonable prequency of logarithm operation, exponential operation and exponentiation operation as well as stronger security, which is more suitable for TWLU data transmission compared with other schemes.

Combined finite element method and analyses on its convergence and accuracy

QING Guanghui, Wang Bo爷ao

2019, 37(1):  60-64. 

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Combined finite element formulation is built according to modified H -R variation principle and minimum potential principle. Firstly, the Euler equation expressing the relationship between out -plane stress and displacement is derived from discretized H-R variation principle. Secondly, the Euler equation expressing the relationship between displacement and out-load is deduced from potential principle, the displacement solution can be independently obtained from Euler equation. Substituting the displacement solution into the first Euler equation, the out-plane stress solution can be obtained. Considering the different materials consisting of the structure, the in-plane stress solution can be obtained by a set of linear equations, avoiding the direct stress solution method basing on constitutive relationship at element level. Example shows that the numerical result of linear eight-noded NCCFE is stably convergent, balanced and reliable with fast convergence speed and high accuracy.