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Radar direction finding is an essential cooperative monitoring method for aircraft, and the directional parameters of the direction finding antenna determine the accuracy of direction finding. A modified amplitude comparison direction finding model is proposed based on the traditional principle of adjacent amplitude comparison direction finding and the error of amplitude comparison direction finding. Based on the correction of amplitude comparison direction finding model, an error correction genetic simulated annealing (COR-GSA) algorithm is proposed to identify unknown directional antenna directionality parameters by determining the antenna directionality parameters that need to be identified. Identification experiments are conducted using a self-designed dual channel direction finding receiver, and 1 000 sets of aircraft real azimuth data are used for verification. The results show that using the COR-GSA algorithm to identify antenna directional parameters has the highest direction finding accuracy. Finally, the identified antenna directionality parameters are used to track the aircraft's azimuth, and the tracking error is reduced by 18. 3% compared to the tracking error without azimuth correction. [ABSTRACT FROM AUTHOR]

Spare parts support is essential to the safe and reliable operation of civil aircraft. Civil aircraft are operated in different regions, and spare parts support based on customer demand is also affected by the regional environment and transportation methods. In order to realize the agile support of civil aircraft spare parts, this paper comprehensively considers the influence of multiple factors, and proposes the nested analytic hierarchy process (NAHP) method based on the balance of the spare parts support network nodes, as well as the multi- region spare parts support network model for civil aircraft based on the genetic algorithm (GA). Combining the characteristics of civil aircraft operations in multiple regions, the factors affecting the spare parts support network are researched, and the NAHP is used to weigh and analyze the spare parts support network nodes, and the target nodes of the spare parts support network are obtained by ranking the importance of the candidate nodes. Then, taking timeliness as the optimization goal, a multi-regional spare parts support network node type positioning and multimodal transport route optimization model is constructed, which is solved by the GA that is designed to improve applicability. Finally, the effectiveness of the developed method and model is verified by comparing with the artificially planned spare parts support plans. The results show that the proposed method can reasonably determine the type and radiation range of the spare parts support network node, and at the same time complete the spare parts support task in the shortest time. It can provide feasible methods and ideas for the construction of the spare parts support network for civil aircraft operating in multiple regions. [ABSTRACT FROM AUTHOR]

Railways in treacherous mountainous areas are characterized by steep topography, complex geological conditions, and complexity in railway engineering. The comparison and selection of route schemes are attributed to properties, such as multi-objective, multi-factor, and complexity. The influencing factors are full of uncertainty, and the decision-making process is of randomness, factitiousness and ambiguity. To make a scientific and reasonable comprehensive comparison and selection of different route schemes, this paper proposes a cloud-model-based optimization model for route schemes in treacherous mountainous areas and takes the plateau railway as a study instance. It is concluded that the CK scheme for the section from Bomi to Tongmai has the highest degree of comprehensive membership, which is consistent with the actual demonstration results, and the digital eigenvalues of cloud model can better reflect the influence of each evaluation index on the decision- making of route scheme. This study verifies the applicability and effectiveness of the model, and provides scientific basis and technical support for the selection of railway route schemes in complex and dangerous mountainous areas. [ABSTRACT FROM AUTHOR]

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With the continuous development of modern electronic confrontation technology and military equipment, the detection ability of passive detection system to aircraft and its active electronic equipment has been significantly improved. The survivability and penetration ability of aircraft in modern combat environment are seriously threatened. Aircraft radio frequency (RF) stealth technology is an important technical way to improve aircraft battlefield survivability by controlling the RF radiation of airborne radar, data link, altimeter, electronic confrontation and other active electronic equipment, and plays an important role in today7 s battlefield. In this paper, the research of aircraft RF stealth technology is overviewed. Firstly, the basic concept and research status of RF stealth technology are described, and the basic principle and realization way of RF stealth technology are introduced. Then, the research achievements in the field of RF stealth technology are reviewed from the aspects of RF stealth performance evaluation system, minimum radiation power control, low sidelobe digital beamforming of design RF stealth signal waveform, multi-sensor cooperation and management, etc. Finally, based on the summary and analysis of the existing research achievements, aiming at the problems existing in the development of RF stealth technology, the future development trend of aircraft RF stealth technology is prospected. [ABSTRACT FROM AUTHOR]

In the process of ejection take-off，shipboard aircraft are subject to large load，large acceleration， short distance and short time，as well as the influence of atmospheric disturbance and shipboard movement. There is a complex strong nonlinear multidisciplinary dynamics coupled problem. A simple multi-body dynamic model of shipboard aircraft-ejection system is established. Under the action of ship surface shaking load and cross wind load，ADAMS is used to conduct rigid-flexible coupled multi-body dynamic simulation analysis of shipboard airframe ejection take-off，and the overload transfer path and strain distribution of airframe during ejection take-off are obtained. Through the comparison between the simulation analysis and the experimental data in the related literature，it is shown that this simulation method can effectively simulate the ejection take-off process of shipboard aircraft under the strong nonlinear and complex load coupling， providing reference for the whole process research of shipboard aircraft ejection take-off and the design of fuselage structure. [ABSTRACT FROM AUTHOR]

Aircraft parts have the characteristics of large size and complex structure. The traditional single measurement method，such as laser tracker，is more and more difficult to meet the needs of high precision and high efficiency measurement of aircraft intelligent manufacturing due to the low efficiency of measurement. As a new combined measurement method，the flexible measurement technology of large-scale measurement has broken through the problem of low measurement efficiency of single measurement equipment. With its advantages of high precision and high efficiency measurement，it has shown a strong development and application prospect in the field of aviation measurement. Aiming at the research of automatic flexible largescale measurement technology in the aircraft manufacturing process，this paper first summarizes the relevant progress of aircraft measurement field construction. Secondly，the research progress of flexible automatic scanning path planning is introduced. Then， the application status of flexible measurement in the measurement of aircraft skin clearance，overall level measurement and digital preassembly are listed. Finally， the research of aircraft automatic flexible large-scale measurement technology is of great practical significance to improve the quality control of aircraft manufacturing process. [ABSTRACT FROM AUTHOR]

The experimental investigation of blockerless cascade thrust reverser based on secondary injection was conducted on the dual flow transonic and supersonic cascade test facility. Effect of parameters including fan outlet pressure ratios, secondary pressure ratios, secondary injection positions and secondray injection angles on the performance of blockerless cascade thrust resver were studied. The final results show that fan outlet pressure ratios and secondary pressure ratios has some complex relationship. When secondary pressure ratio less than a certain value, cascase reverse mass flow decreases with the increase of fan outlet pressure ratio, however if secondary pressure ratio esceed the value, it would present a opposite trend. In the whole experimental conditions, there exist a best secondary injection position (58.77 mm ≤ Xj ≤ 77.87mmgle (θ - 60°) achieving highest thrust reverse. [ABSTRACT FROM AUTHOR]