Table of Content

25 October 2019, Volume 37 Issue 5

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Civil Aviation

Optimization and implementation of ADS-B spoofing attack detection based on FPGA+DSP#br#

HU Tieqiao, LI Hengchang

2019, 37(5):  1-4. 

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In order to solve the problem of spoofing attack in ADS-B system, an ADS-B spoofing attack detection method based on spatial correlation is optimized according to the working characteristics of FPGA and DSP. Aiming at the complex process of covariance matrix calculation as well as eigen vectors and eigen values acquisition using matrix decomposition, the original algorithm is optimized by calculating the phase differences between signals of different channels in array to obtain the steering vector. The optimized algorithm reduces the calculation complexity and becomes more suitable for implementation on the platform of FPGA and DSP. Results show that the algorithm works well on the hardware platform and the real-time system can effectively identify real aircraft from ghost.


Influencing factors of aera control system operation efficiency#br#

ZHAO Yuhuan, CAO Xingwu, CUI Ziyang, ZHANG Zhaoning

2019, 37(5):  5-11. 

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As there are many factors affecting the operating efficiency of area control system with various influencing degrees, it is necessary to rank the influencing factors, find out the key influencing factors and propose efficiency control measures. Based on the operational process of area control system and ‘man-machine-environment management’ system engineering theory, the influencing factors are given and described by intuitive triangular fuzzy number from the following four dimensions: flight delay time, reduction of flight flow, aircraft number in the sector, and aircraft handover within the unit time. A sorting model combined with TOPSIS and vector projection method is built to find the key influencing factors. Case analysis proves the feasibility of the ranking model, and corresponding efficiency control measures are supplied.


Simulation on thermoelectric generation with piston aero engine exhaust#br#

NIE Erbing, XU Chen, GAO Mingyang

2019, 37(5):  11-5. 

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Thermoelectric generator can recover the waste heat energy from the piston aero engine exhaust gas and reduce the engine crankshaft load and fuel consumption. Based on lumped parameter method and thermal resistance analysing method， the simulation model of engine and TEG is built by using GT-POWER and calibrated with experimental data. TEG output power differences and reasons in road vehicles and airplanes are studied, the influence of altitude on TEG output power is explored and the fuel-saving effect of TEG is calculated. Result of the current research supplies theoretical and data basis for engineering application of TEG in the piston aero
engine exhaust heat recovery.


Harmonics and inter-harmonics real-time aircraft power detection system#br#

ZHANG Chao, ZHAO Zhiheng, WU Enming

2019, 37(5):  16-20. 

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Variable frequency technology is commonly used in aircraft power system, harmonics and inter-harmonics detection is of great significance for the safe operation of aircraft. Windowed interpolation FFT-RBF algorithm is proposed to detect harmonics and inter-harmonics, and real-time detecting system is designed. Firstly, the windowed interpolation FFT algorithm is used to detect the signal frequency bands, and then the RBF algorithm is used to measure the bands. Comparison between Matlab simulation and detecting results shows that the new algorithm is more accurate and has better real-time feature.


Calculation method of aircraft bird strike risk#br#

WANG Wei, XIANG Hongda

2019, 37(5):  21-24. 

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Aircraft bird strike has become one of the safety operation risks for civil airports in China, but there is no mature risk calculation method at present. Probability model of bird strike is established taking A320 as instance. The current model has higher calculating accuracy, providing quantitative value of bird strike risk probability for airport anti-bird and aviation safety decision making.


Motion control method of airport pavement deicing vehicles#br#

CHEN Fei, LI Longpu, LI Si

2019, 37(5):  25-29. 

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To improve the mechanized operation efficiency of airport pavement deicing, a motion control method based on spectral theory is proposed. Firstly, common deicing vehicles and formation control methods are described. Then,based on the Laplacian matrix eigenvectors and relevant theories, the deicing vehicle motion control method suitable for the airport environment is constructed. Finally, different motion forms of deicing vehicles in the actual operation process are simulated by using the proposed motion control method. Results prove that the proposed method can achieve the expected formation and improve working efficiency.


Airport runway area detection for PolSAR image based on robust fuzzy C-means clustering#br#

CHENG Zheng, HAN Ping, HAN Shaocheng

2019, 37(5):  30-34. 

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The edge pixels of airport runway may be misclassified due to category ambiguity. Therefore, a runway area detection method for PolSAR image based on robust fuzzy C-means clustering is proposed. Firstly, in order to avoid the sensibility to initial centers and local optimum occurring in fuzzy C-means clustering, the polarization decomposition theory is utilized to segment the original image and obtain appropriate initial centers. Then the regions of interest (i.e. suspected runway areas) are extracted from the classification results, which are obtained by the robust fuzzy C-means clustering method based on Wishart distance. Finally, structural features of runway are used to identify the extracted areas and finalize the real runway area. Simulation results show that the proposed method has higher accuracy, faster speed, and better visual effect comparing with the other two algorithms.


Image segmentation based on two dimensional Tsallis entropy multi-threshold and DE algorithm#br#

WANG Kun, ZHOU Yi, WU Yiming

2019, 37(5):  35-40. 

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It is easy to lose edge information when using the traditional segmentation algorithm, which leads to wrong judge of the damage area size. Aiming at the infrared image segmentation of aircraft skin damage, a segmentation method combining 2D Tsallis entropy multi-threshold and improved DE algorithm is proposed. Firstly, the initial population number, i.e. the number of thresholds is determined, calculating the q value of each region by using the threshold value. Then the initial threshold mutation and intersection are conducted, selecting the optimal threshold according to the Tsallis entropy value, and the optimal threshold is used as the initial threshold of the
next differential evolution. The optimal threshold is used to calculate the scaling function F of differential evolution algorithm, repeating the differential evolution until the global optimal threshold is obtained.Experiments show that compared with traditional methods, the current algorithm can effectively improve the segmentation efficiency as well as the quality of segmentation results.


Simulation on aircraft cabin air pollutant distribution under point source effect#br#

FEI Chunguo, CAI Shanshan, WANG Yang, JI Yuchu

2019, 37(5):  41-46. 

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In order to obtain the distribution and influencing range of gas pollutants in cabin released by single point source,the complete economy class cabin model of B737 -700 with 20 rows of seats is established and the diffusion process of gas pollutants under the influence of cabin AC system is simulated by Fluent. Comparing the difference among pollutant distribution with pollutant source separately locating on sidewall, on luggage rack and in seat, the relation between pollutant distribution range exceeding the threshold of dangerous concentration and the releasing rate of pollutant source is analyzed. Simulation results show that the same pollutants released at different locations have the similar influencing range under the action of AC system. The pollutant influencing range exponentially increases with the releasing rate.


Group-based rapid detection algorithm of flight short-term conflict-pairs#br#

GUAN Jing, ZHANG Jingwei

2019, 37(5):  46-50. 

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In order to realize real-time detection of aircraft conflict, a group-based aircraft conflict-pair fast detection algorithm is established. The algorithm uses four square-divided cover sets to construct subspaces in a certain altitude. Hash table is used to accelerate the grouping process. Judgments are taken in each group, and then aircraft conflict-pairs are extracted only if the distance between two aircrafts is less than the given safe interval.Simulation result shows that this algorithm can avoid missing conflict-pair and reduce detection times, validating its superiority.


Engineering and Technology

Design and FEM analysis on 3D flexible clamping fixture platform of thin-wall parts#br#

ZHANG Li , GUO Qiaorong

2019, 37(5):  51-54. 

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A 3D flexible tooling positioning platform is developed to solve the problems of difficult positioning and easy deformation during the machining and assembling process of curved thin-wall parts. Firstly, the physical and digital models of this 3D flexible platform are built. In order to locate and adjust the orientation of thin-wall surface parts, this platform is composed of high-precision standard modules, positioning parts and clamping parts.Then, the static and free vibration analyzing models of the flexible platform are develped based on commercial finite element software, studying the mechanical properties of the platform. Numerical results show that the flexible clamping fixture platform has sufficient stiffness and strength. The structural vibration transmitted from the assembling units will not cause the resonance of supporting structure.


Stress concentration of composite laminates with circle hole#br#

QING Guanghui, WANG Shaobo

2019, 37(5):  55-59. 

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Due to the unique mechanical behavior of composite laminated plates and shells, there is no exact solution for calculating the stress concentration factors of such structures. Therefore, test or finite element model of the fine mesh are usually used to analyze this kind of problem. Based on the enhanced strain theory and the generalized H-R variational principle, a new noncompatible generalized mixed formulation is proposed. And then, a nonconforming generalized mixed model is established for the stress concentration factor analysis of composite laminates with holes. Numerical results show that the stress obtained by noncompatible generalized mixed finite element model has higher precision, stronger reliability and wider applicability.


Basic Science

Two direction S-dominance-based probability rough set and its application#br#

TAO Zhi, WANG Dan

2019, 37(5):  60-64. 

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S-probability rough sets and dominance-based rough sets are both important extensions of rough set theory.However, they both have their own limitations. Based on the advantages of the above two models, a two-direction singular dominance-based probability rough set model is proposed. The new model not only considers the dynamic statistical characteristics of the system but also takes into account the effective processing of actual preference information system. The model has certain ability to resist noise interference. At the same time, it has higher classification accuracy and classification plausibility, which is suitable for dealing with dynamic multi-attribute decision-making problems with preference information.