Abstract:The emergence of Mars UAVs provides a new idea for Mars exploration and is an important paradigm for future deep space exploration. This paper compares the differences between Mars and some relevant surface environmental parameters on Earth, analyzes the main uses and the difficulties that Mars UAVs need to overcome, and clarifies the importance of Mars UAV experimental benches. The technical features and functional advantages and disadvantages of the Mars UAV experimental platform developed by domestic and foreign research institutions are introduced in detail, and the need for the experimental platform to have a simulated Mars environment and measure relevant parameters is summarized. On this basis, the idea of building a Mars UAV experiment platform is proposed, the overall design ideas and thoughts are given, and the prospect of the application of the Mars aerodynamics experimental platform is made.

Abstract:For near space unmanned aerial vehicles (NSUAVs), efficient power type is the key to support their long flights. It is considered that the “airborne liquid hydrogen storage + hydrogen fuel cell” scheme is in line with the trend of NSUAVs’ greater endurance and larger payloads. In allusion to this scheme, the technology status of hydrogen supply processes, airborne hydrogen tanks, air supply processes and water/heat management for fuel cells are summarized in this paper. Technical analysis and summaries are carried out on hydrogen delivery methods, structures and materials of airborne hydrogen tanks, as well as the influences of low pressure environment on the suction performance of air compressors and heat dissipation performance of fuel cells. The development direction of relevant technologies is also discussed, providing reference for later studies.

Abstract:Flow-induced noise is a common problem in practical engineering. The classical acoustic analogy model is insufficient to evaluate the characteristic distribution of the acoustic field using only acoustic pressure as a reference. This paper starts from a four-dimensional linear wave equation with sound pressure and sound velocity vectors as variables, by choosing the Kirchhoff surface to enclose a nonlinear acoustic source and combining with the convective Green"s function, the four-dimensional acoustic frequency-domain integral equation for a uniformly moving medium is developed. Numerical prediction studies were conducted for stationary, rotating monopole and dipole sources. The results indicate that the distributions of the sound pressure and acoustic velocity obtained by the present proposed method are in good agreement with the analytical solutions. In contrast to the stationary flow case, the acoustic field distribution of the stationary point source in the uniform flow exhibits a convection effect. On the other hand, the acoustic field distribution of the rotating point source exhibits a strong Doppler effect and convection effect due to the joint influence of the uniform flow, the self-excitation frequency, harmonic order, and rotational frequency of the point source. The refined study of aerodynamic vector noise with uniform flow in this paper can provide technical support for the assessment of acoustic energy and the prediction of transmission paths. Additionally, it provides a theoretical basis for noise reduction studies.

Abstract:The resistance characteristics of aero-engine high-altitude ice crystal particles will affect the movement of ice crystals. In order to explore the influence of different shapes of ice crystals on the drag coefficient, the paper adopts the method of high-speed camera tracking to investigate the drag coefficient of spherical particles and non-spherical particles (long cylinder, short cylinder and disk). The Reynolds number and drag coefficient of different particles are obtained according to the velocity of particles at uniform velocity, and the correlation formula for calculating drag coefficient of different particles in the working condition range is obtained by fitting experimental data. Finally, the correlation formula is verified by using experimental data other than fitting data. The results show that the Reynolds number ranges from 3961 to 24144. The average relative error between the calculated and experimental values of the four particle resistance coefficients is less than 5%.

Abstract:Aviation is one of the eight key industries of carbon emission. The carbon emission of aviation industry is mainly affected by the carbon emission of aero-engine. Therefore, it is urgent to carry out the research on the measurement method of aero-engine carbon emission. The life cycle assessment is used as a quantitative method for the carbon footprint of aero-engines. The life cycle carbon emissions of aero-engines are divided into fuel cycle carbon emissions and material cycle carbon emissions, and statistics are carried out separately. The aero-engine system boundary is divided, the data collection that should be carried out in each stage is proposed, and the data is required. This paper obtains a relatively complete set of aero-engine carbon emission measurement methods. This method comprehensively evaluates the carbon emissions of aeroengines from the perspective of life cycle, which can provide guidance for the measurement of carbon emissions of aeroengines throughout the life cycle, and provide a theoretical basis for emission reduction from the perspective of fuel and material.

Abstract:In the current research on the fatigue state of controllers using radiotelephony communication, most of them only consider the changes of voice in the time domain or frequency domain, while ignore that fatigue will affect the time domain and frequency domain at the same time. In this paper, the voice of radiotelephony communication in the three fatigue states is converted into speech spectrum images that can reflect the characteristics of both the time domain and frequency domain, and the grayscale co-existence matrix (GLCM) is used to extract the typical feature parameters in four dimensions, compare the changes of the characteristic parameters of the controllers in different states, and confirm that the selected features have a good discrimination. The selected features were detected as the input features of the controller fatigue detection model, and the detection accuracy of using the spectral pattern features combined with the traditional features as the input features was the highest, reaching 95.49%, which was 4% higher than that of the traditional features alone. The results show that the change of controllers fatigue state will be intuitively reflected on the spectrogram and will have an impact on its eigenvalues, and good results can be obtained by using this influence to detect the controllers fatigue state.

Abstract:Xinjiang is an important area linking China with Central Asia and Europe, and is a vital land pivot point of China"s "One Belt, One Road". As the number of flights increases year by year, the control pressure in Xinjiang control area increases year by year, and the problems of uneven load distribution and increasing conflict points in the sector are becoming more and more serious. This paper forecasts the traffic growth of the Xinjiang control region in 2035 in the light of the development requirements of China"s "One Belt, One Road" and "Air Silk Road", and then conducts a capacity assessment of the current sector classification scheme based on the controllers" workload. Finally, computer simulation technology is used to evaluate the sector designation scheme in 2035. The simulation results show that the new sector division can effectively reduce peak day traffic and peak hour traffic. Through reasonable division of sectors with high controller load, the control pressure has also been significantly alleviated. The simulation verifies the rationality and effectiveness of sector division.

Abstract:In recent years, with the rapid development of civil aviation transportation, the research of aircraft maintenance routing has been paid more and more attention. In order to explore the research status, hot spots and frontier trends of the aircraft maintenance routing problem, this paper takes the domestic and foreign literatures on aircraft maintenance routing collected in the core databases of China National Knowledge Network (CNKI) and Web of Science from 2000 to 2022 as the analysis data. The CiteSpace V software is used as a auxiliary research tool to analyze the scholars, institutions and cooperative relationships in the field of aircraft maintenance routing. Combining the knowledge maps and literature content, the hot spots and frontiers of research in this field are summarized. Considering the domestic aircraft maintenance routing research, research suggestions are put forward for the research trend and focused research content in this field in China, and provide reference for future aircraft maintenance routing research scholars.

Abstract:Least risk bomb location structure is a device for placing suspicious explosives on the aircraft. Exploring the influence of structure size and explosive location on its anti-explosion performance can provide a reference for improving the design. Based on the method of combining orthogonal experimental design with numerical simulation, the maximum strain and deformation of each dangerous part of LRBL structure are used as evaluation indicators. The range analysis method and variance analysis method are respectively used to carry out parameter sensitivity analysis on the five influencing factors of the tank wall thickness, bottom cover thickness, connection boss thickness, shear pin diameter and explosive position of LRBL structure. The results show that when the explosive equivalent was determined as 200g, the significant degree of influence of each factor on the antiknock performance of the LRBL structure from large to small was as follows: explosive position, tank wall thickness, bottom cover thickness, boss thickness and shear pin diameter; Based on comprehensive analysis of evaluation indicators, the LRBL structural design scheme at the optimal level of each factor is obtained. The research results have guiding significance and reference value for the application of LRBL structure in engineering practice.

Abstract:As a necessary test of aircraft development，the ground vibration test of full-size aircraft has the characteristics of multiple coordination units, complex system, long implementation time and high risk. Facing the need of efficient development of advance aircraft, it is necessary to improve the capability of the test, by introducing the digital means. In this paper, the flow of ground vibration test in traditional mode has been summarized, the elements of digital experiment has been analyzed and the digital test programme has been constructed preliminarily. Based on the application of ground vibration test on rocket, the significant benefits in reducing test risks and improving test efficiency of this mode are shown, and it is necessary to promote the development of digital real fusion simulation and application platform, to promote the implementation of this technology.

Abstract:The Environmental Qualification Test of civil aircraft airborne equipment is to demonstrate that the equipment meets the applicable environmental standards, and further meets the Technical Standards Order applicable to it, which is of great significance to the airworthiness certification of airborne equipment. At present, the Environmental Qualification Test of civil aircraft airborne equipment in domestic is still in the continuous improvement stage. This paper takes the environmental qualification test of certain airborne equipment as an example, introduces a set of workflow for the Environmental Qualification Test, including three stages: Environmental Qualification Test plan development, environmental test procedure development, and qualification testing. Then combined with the Minimum Operational Performance Standard (MOPS) applicable to the equipment and the DO-160 standard (Environmental Conditions and Test Procedures for Airborne Equipment), it describes in detail about the work content and focus of each stage in the workflow, as well as the planning of airworthiness liaison and suggestions. This equipment has got the TSO approval, indicating that this workflow can be effectively applied to the Environmental Qualification Test of airborne equipment and support for the airworthiness certification, and can also provide reference for the Environmental Qualification Test of subsequent airborne equipment.

Abstract:The aircraft AC power generation system is the key subsystem of the power supply system and the main source of power for the whole aircraft, so a complete safety analysis is required. Methods such as fault tree analysis, failure mode and effect analysis are used for traditionally safety analysis, and less attention is paid to safety issues caused by nonlinear interactions between system components. The article introduces the basic structure of the AC power generation system of a typical large passenger aircraft, using the method of combining system theory process analysis and the theory of timed automata formal analysis, build the safety control structure diagram of the AC power conversion process, identify Unsafe Control Action (UCA), and generate relevant causal scenarios by integrating Failure Mode and Effect Analysis(FMEA), combined with formal tools based on the theory of timed automata for system modeling and UCA verification. The comparison with the accident investigation results of typical power system shows that the method used can effectively identify the cause of the accident and conduct a comprehensive analysis, which can be used as an effective supplement to the traditional safety analysis method of aircraft power system.

Abstract:Experiment and numerical simulations were carried out to study the performance of bird strike with blades of an engine primary compressor. Firstly, the bird impact test, in which the bird weight, velocity and rotate speed of engine blades were 1000g, 195m/s, 8525 r/min respectively, was made in a vacuum space. Then the full scale finite element calculation model of bird striking on blades of an engine primary compressor was established, and the numerical simulation results are extremely identical with the test results with acceptable error to show the reliability of simulations. Also, the ability of engine blades against bird strike in different situations was researched. The results indicated that big bird impact leads to a worse situation compared with medium birds flock and small bird lock. Large deformation appears at the tip of the blades due to the impact at the tip part, while impact at the root and middle of the blades will cause a large concentrated stress around the root of blades. The research methods and our conclusions in the current paper are significant to the design of engine blades against to the bird impact.

Abstract:The bird-swallowing ability of engine must meet the requirements of the national military standard and airworthiness. It is necessary to propose a reliable method to assess the bird-swallowing ability of the engine before bird-swallowing tests, the test risk can be reduced and the test success rate can be increased. Based on the bird-swallowing capability simulation and verification project of a turbofan, this paper proposes a method for evaluating the bird-swallowing capability of an engine based on simulation analysis, momentum analogy and contact stress analogy. According to the relevant standards and specifications, the test requirements were determined, and the bird-swallowing test was carried out and verified.The test results and assessment methods can provide reference for the development of other turbofan models.

Abstract:Aeronautical electronic equipment is used for data collection during flight, usually fixed to the nose radome using mounting brackets, studying the stiffness and first-order frequency performance of the mounting brackets to avoid plastic deformation and resonance during flight, which is of great engineering significance for improving flight stability. The static strength and modal analysis of the mounting bracket under inertial load show that the bracket has good Bending stiffness, but the first order frequency is low. Using a sensitivity analysis method to determine the design variables of the installation bracket, with the goal of minimizing the total weight of the structure as the optimization objective, the thickness of each component of the bracket is optimized while ensuring the stiffness and first-order modal performance of the installation bracket. Vibration tests are conducted on the optimized installation bracket structure, and the test frequency values and finite element calculation values are in good agreement, verifying the accuracy of the finite element modal analysis method. The results show that the stiffness of the optimized installation bracket structure remains basically unchanged, with an increase of 18.09% in first-order frequency and a weight reduction of 19.33%. The improved design meets the equipment installation requirements.

Abstract:As an important new part of Airborne Integrated Surveillance System (ISS), Automatic Dependent Surveillance-Broadcast (ADS-B) system shows advantages in surveillance and efficiency under the premise of ensuring flight safety, leading the development of future surveillance technology. By analyzing the development process of airborne ADS-B products and technologies at home and abroad. Then, from the perspective of ensuring flight safety and efficiency, key technologies of ADS-B system are analyzed and summarized. Finally, the development trend of the technology is discussed and prospected by the concept of next generation airspace operation, and 4 future development directions of ADS-B technology are proposed, which provide the development direction for the development of ADS-B technology of airborne ISS. This will promote the development of ADS-B technology in practical operation and theoretical research.

Abstract:As the complexity of modern aircraft systems continues to grow, traditional development methods are be-coming increasingly challenging in terms of management and maintenance. Model-Based Systems Engineer-ing (MBSE) provides a comprehensive and integrated approach to systems engineering, enhancing communi-cation, collaboration, and traceability throughout the development process. We first evaluate the development process of aviation flight control systems in current systems engineering practices, elucidating the drawbacks of traditional development approaches and the core principles and advantages of MBSE, as well as common-ly used tools and methods in its implementation. We then demonstrate how MBSE uses models to support the specification, design, analysis, verification, and validation of complex systems during the development of flight control systems. Finally, we outline future research directions, including the development of advanced MBSE tools and methods, the prospects for combining MBSE with agile development, and the need for im-proved interoperability and standardization in MBSE practice. This paper provides resources and insights for aviation industry professionals, systems engineers, and researchers interested in leveraging MBSE methodol-ogies and tools to improve the design, development, and performance of flight control systems.

Abstract:It is well known that there are several vertical flight phases for the aircraft in the flight. The cruise flight phase takes most of the flight time, flight distance and fuel consumption, so it is important and necessary to develop the FMS vertical trajectory prediction algorithm for the cruise flight phase, aiming to improve the economy, comfort and safety of the flight. In order to meet the versatility of the vertical trajectory prediction algorithm between different types of aircraft in the cruise phase and improve the accuracy and reliability of the prediction, the algorithm of vertical trajectory prediction for cruise flight phase is proposed in this paper. By calculating the cruise speed profile and constructing the realistic atmospheric model of prediction, and then calculating the cruise fuel flow data based on the aircraft model of first-principles, the vertical trajectory prediction for the cruise phase is given by designing the vertical trajectory prediction algorithm logic. Finally, the effectiveness and accuracy of the algorithm are verified by ground simulation and air flight test. The results show that the vertical trajectory prediction algorithm of FMS cruise phase based on the aircraft model of first-principles can predict the cruise trajectory of the aircraft, and the prediction accuracy error is less than 1%.

Abstract:The data fusion of radar and ADS-B is an effective method to surveille the ‘black flights’ and flying birds. However, the tracking performance of the two sensors has large differences and is easy to fluctuate, which will bring a decline in fusion accuracy. This paper proposes a data fusion method of radar and ADS-B based on track quality assessment. Firstly, the effects of local track accuracy, data update times and sensor measurement errors on local track quality are analyzed and quantified into corresponding assessment factors. Secondly, these assessment factors are combined to calculate the quality weighting factors of the local track. Finally, the asynchronous track fusion processing of radar and ADS-B is completed based on the distributed fusion structure. The results of simulation experiments show that the fusion processing method proposed in this paper can effectively improve the fusion accuracy, and the tracking errors are better than the traditional algorithms when the sensor tracking performance fluctuates. The fusion effect of engineering application also verifies that the proposed method is helpful for the integrated surveillance of low-altitude cooperative and non-cooperative targets.

Abstract:Due to the advantages of low cost and no casualties in unmanned aerial vehicle (UAV) autonomous air combat, it has attracted increasing attention. This paper is based on the deep deterministic policy gradient (DDPG) reinforcement learning method. Building upon the situation evaluation function as the reward function for reinforcement learning, a comprehensive reinforcement learning environment is designed that considers flight altitude limits, flight overload, and flight speed limits. The interaction between the DDPG algorithm and the learning environment is achieved through the fully connected carrier speed control network and the environment reward network. The end condition for air combat is designed based on abnormal height and speed, missile lock time, and combat time. By simulating one-on-one air combat, the effectiveness of this combat control method is validated in terms of learning under environmental constraints, situation evaluation scores, and combat mode learning. This research can provide guidance for the further development of autonomous air combat.

Abstract:(小5号黑正)：As the demand for intelligent application in airborne embedded computing system is increasing, the convolution neural network model with excellent performance can effectively solve the problems of target recognition and edge detection in air combat scenes. However, the huge weight parameters and complex network layer structure of convolutional neural network make its computational complexity too high, and the required computing resources and storage resources also increase rapidly with the increase of network layers, so it is difficult to deploy in airborne embedded computing systems with strict requirements on resources and power consumption, which restricts the development of airborne embedded computing systems towards high intelligence. Aiming at the demand of ultra-lightweight intelligent computing in the resource-constrained airborne embedded computing system, a set of optimization and acceleration strategy of convolutional neural network model is proposed. After ultra-lightweight processing of the algorithm model, a convolutional neural network accelerator is built by combining acceleration operators, and the function verification of network model reasoning process is carried out based on FPGA. The experimental results show that the designed accelerator can significantly reduce the occupancy rate of hardware resources and obtain a good algorithm speedup ratio, which has important technical significance for the design of airborne embedded intelligent computing system.