Journal of Civil Aviation University of China

ADS-B spoofing detection method based on spatial correlation

WU Renbiao, CHEN Lei, LU Dan

2018, 36(5): 1-6.

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With the widespread use of ADS-B (automatic dependent surveillance-broadcast), security issues of which have also attracted widespread attention. Aiming at its susceptible deception jamming, a jamming detection method is proposed. Firstly, a group of variables are calculated to indicate the DOA changing trend according to message report. Secondly, with the help of signals received by array antenna, another group of variables are computed as the reflection of DOA changing. Finally, Pearson correlation coefficient of the two sets of variables are employed to distinguish whether the target is a real aircraft or a ghost. On this basis, a source consistency detection method is proposed to decrease the false detection rate. Compared with other methods, the current one shows robustness to the amplitude and phase error of the array without consideration of signal爷s origin, thus is suitable for engineering practice.

Performance evaluation of Beidou system for single point service at airport

WANG Jian, WANG Ying, LIU Ruihua, ZHANG Fengzhao

2018, 36(5): 7-11.

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Civil aviation is the high-end user of BDS (BeiDou navigation satellite system), it is necessary to monitor and evaluate the BDS service performance at civil aviation airport. Based on the measured data of BDS constellation from three civil aviation airports test stations, the visibility of satellites, DOP (dilution of precision), positioning accuracy and HPL(horizontal protection level) are analyzed and compared by using the classical service performance analysis method. Results show that the number of visible satellites at two civil aviation airport test stations in Northwest and North China is greater than 7, and the number of visible satellites at the test station in Central-South China is greater than 6, which can meet the requirement in user positioning process; with the condition of 95% probability, the positioning accuracies of the three civil airport test stations are better than 3.522 5 m at horizontal direction and better than 5.424 7 m at vertical direction; the proportion of HPL values less than 556 m is greater than 99.014 2%, which meets the availability requirement of NPA (non-precision approach) flight phase.

Impact of E/F layer ionospheric scintillation on TEC changing rate of GPS

YIN Ping, LI Qingyu

2018, 36(5): 12-18.

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As a natural phenomenon which is possible to reduce navigation performance, ionospheric scintillation mainly occurs in different heights of ionosphere layers at polar area and low latitudes including E/F layers; In order to investigate the effects of E/F layer ionospheric scintillation on ROTI estimated by GPS ground stations, COSMIC and high rate GPS dual-frequency geodetic surveying data are used to conduct detailed analyses. Meanwhile, the predicting ability of GISM is also investigated. Result shows that GPS ROTI is small (ROTI≈0.02TECU/min) when E-layer strong scintillation occurs (S4>0.6), however, ROTI becomes very large (ROTI≥2 TECU/min) when F-layer strong scintillation occurs. Take Hong Kong district as instance, GISM is capable to predict ionospheric scintillation occurring at night(S4predictedvalue≥0.6)while predicted S4 value of daytime scintillation is totally zero. Besides, there is no difference between ionospheric scintillation of E/F layers according to GISM predicted results.

DME interference suppression method based on joint NLS and CS signal reconstruction

LIU Haitao, CHEN Qian, WANG Lei, LI Dongxia

2018, 36(5): 19-23,33.

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To mitigate the influence of DME signal on OFDM receiver of L-DACS1 operating as an inlay system,DME interference suppression method based on joint NLS(nonlinear least square) and CS (compression sensing) signal reconstruction is presented. Firstly, DME signal is reconstructed by NLS and eliminated in time domain. Secondly, the output signal of NLS is filtered by low-pass filter to reduce the out-of-band interference signal and noise signal. Finally, the residual DME signal is reconstructed by CS algorithm and eliminated in frequency domain.Computer simulation results show that the proposed method can effectively suppress DME interference and improve the reliability of L-DACS1 system.

Research on inlet guide vane regulation of civil aviation engine

KAN Yuxiang, CAO Huiling, GAO Sheng

2018, 36(5): 24-28.

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Adjusting the engine inlet guide vane can prevent the occurrence of surge or stall, increase the engine stability and improve the engine performance. On the basis of anti-surge principle of inlet guide vane, the regulation law model of inlet vane is established by the method of reference inlet airflow angle. This model can be used to calculate the installation angle of the adjustable engine inlet guide vanes under different state points, and is compared with the actual position. Results show that except very few complex sectors, the deviation between calculated values and actual values is small. It is proved that the model can well reflect the regulation law of adjustable inlet guide vane, providing reference for engine fault diagnosis and VSV control system design.

Node algorithm and risk analysis based on issuing time of landing clearance

TIAN Xiaoying

2018, 36(5): 29-33.

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According to the latest regulations of CCAR93-R5, it is necessary to replace the abstract conditions of landing clearance issuance with practical timing points. The landing clearance issuing time algorithm under different conditions is proposed. Calculation employing B737-800 operation data shows that there are two checking points(7 km, 5 km) and one decision point (2.5 km) from the landing aircraft to the runway entrance. When landing aircraft approaching to the decision point, the controller can issue landing clearance under one of the following conditions: a) it is observed that the departing aircraft in front has lifted its front wheels and b) it is observed that the landing aircraft in front has entered the exit crossing without obstacles. Taking this result as reference, air traffic controllers can issue landing clearance with accurate timing, reducing runway incursion risk and aviation accidents.

Airport site selection scheme evaluation based on combinated weighting and cloud model

ZHANG Shidi, CHONG Xiaolei, GENG Hao, LI Yan, XU Xiangrui, WANG Wei

2018, 36(5): 34-37.

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Aiming at the subjective indicator weighting problem during traditional decision-making of airport site selection,an approach combining with HAP and entropy is proposed. Combinated weighting and cloud model are both employed to build the current assessment approach of airport site selection. Fuzziness and randomness of evaluation indices are modified. Finally, taking decision-making of one airport site selection as instance, the application procedure of this approach is given, supplying a new method for airport site selection.

Flight skill dimension construction for civil aviation pilot

GAO Li, WANG Yanhong, QI Zhenxing

2018, 36(5): 38-42.

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Traditional flight technique only emphasizes the operation of 'one pole and two rudders'; however, with the continuous improvement of airborne facilities and automation level, the communication and coordination problems among crew members urgently need to be concerned. Only by fully defining the components of flight technique can the pilot's flight skill be further improved. By combining the related literature at different stages, flight skill characteristics are summarized with 20 components of pilot flight skill. With exploratory factor analysis method, the pilot flight technique is mathematically analyzed. Five aspects of airline pilot flight skill are obtained,namely operability and stability, special flight control, flight monitoring, information decision-making as well as crew resource management, providing theoretical support for pilot flight skill improvement.

Human factors analyses in aircraft MRO based on improved HFACS

WU Yaogang, XU Jianxin, MA Chao, HAO Rui

2018, 36(5): 43-47.

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In order to reduce the influence of human factors in aircraft MRO, typical aircraft accidents of a domestic company are analyzed. The improved HFACS model for aircraft MRO is constructed, which can analyze the human factors more effectively with its 17 subcategories. SPSS is employed for chi-square test and odd ratio analysis. Results show that the organization influence is the main cause of accidents, meanwhile, there exists significant causal relation among organization influence, unsafe supervision, premise of unsafe behavior and unsafe behaviors. The correlation between sub-categories should be given more attention in order to fundamentally reduce the occurrence of human factor events.

Application of improved quantum particle swarm algorithm in initial configuration of aircraft spare parts

TIAN Jing, ZHANG Enhao, FU Weifang

2018, 36(5): 48-51.

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Aiming at premature convergence and imperfect global optimization ability of quantum particle swarm optimal algorithm in optimal allocation, evolutionary factors and contraction expansion coefficient are improved. From the aspect of aircraft spare parts allocation model building, maximum unit cost system guarantee rate model is constructed, in which cost variables are introduced based on traditional goal of improving system assurance rate.Boeing's first stage equipment list is used as optimized object to validate the model, proving the better optimal result and faster convergence rate of the improved algorithm.

Simulation and optimization of airport passenger security screening process based on Anylogic

ZHAO Zhenwu, LI Xinyuan

2018, 36(5): 52-55.

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Based on pedestrian library simulation developing platform of Anylogic, the airport passenger security screening channel simulation model is established according to related ratios by using object -oriented simulation technology and social force model. The bottleneck found in the airport passenger security screening process lies in the lack of space for passengers to organize their luggage, which leads to low passing rate per unit time while long time for passengers going through the security channel. The optimization scheme, namely, increasing the space for passengers to organize the luggage, is put forward and then verified by simulation modeling method to significantly improve the efficiency of passenger security screening.

Parametric dynamical modelling of planetary reducer based on finite element

CHI Zhuang, WANG Wei

2018, 36(5): 56-59.

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Planetary reducer is widely used in vehicles, robots and other equipments, the existence of side clearance has a great influence on the accuracy and service life of planetary gear system. Finite element analysis method and ANSYS APDL are applied to complete the 3D model of planetary reducer, the meshing process is simulated through contact force definition. Contacts and meshing of a 2K-H planetary gear system is accurately simulated and the numerical simulation calculation is carried out through LS-DYNA explicit dynamic solver. The finite element dynamic responses of different tooth side clearances are studied by parameterized modeling. An effective method for the analysis and research of planetary gear system is provided, supplying useful reference for further optimization of the theoretical model.

SOC prediction of LiFePO4 cell based on GSO-BP neural network

WANG Bingyuan, ZHANG Dandan

2018, 36(5): 60-64.

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Based on the charge and discharge mechanism of LiFePO4 cell, a prediction model is developed for the SOC (state of charge) of Lithium iron phosphate battery based on BP neural network. As GSO (glowworm swarm optimization) does not require gradient information of the objective function，and it is not easy to fall into the local optimum, it can be used to optimize the weight and threshold of BP neural network and to improve SOC prediction accuracy of lithium iron phosphate battery. Experimental results show that SOC prediction of lithium battery based on GSO-BP neural network is more accurate than that of other neural networks, prediction error of the current model is less than 1%, which can meet the technical requirement of SOC prediction error of 5%.

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