Modern Defense Technology

Development and Testing of Multi Rotor Unmanned Aerial Vehicle Noise Source Tracking and Positioning System

Jingyu HE, Jizheng LIU, Zhichen YANG, Dongdong WANG, Ping OU

2024, 52(3): 1-8. doi:10.3969/j.issn.1009-086x.2024.03.001

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Multi-rotor drones are increasingly becoming a threat to critical facilities while bringing convenience. This article focuses on the difficulty of tracking and detecting low slow small unmanned aerial vehicles （UAVs）， and develops a UAV tracking， detection， recognition， and positioning system based on microphone array sound source localization. The system acquires UAV noise signals in real time， and then uses a wavelet transform-based beamforming time-frequency sound source localization algorithm for UAV noise source localization， and finally integrates the position of the multi-rotor UAV obtained by inversion of the microphone array and the image captured by the video. Tests conducted in a fully anechoic room have shown that the positioning system can accurately track the lateral flight and up-and-down flight of drones， accurately detect the position of drones even in blind spots of cameras， and effectively compensate for video detection. And the positioning accuracy of the system is 92.2%， which is better than that of similar systems.

Numerical Simulation of Tilting Wing and Rotor UAV During Transition Flight

Zonghui WANG, Yunjun YANG, Hongrui ZHAO, Jiaxiang ZHAO

2024, 52(3): 9-19. doi:10.3969/j.issn.1009-086x.2024.03.002

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Compared with traditional configuration tiltrotor aircraft， tilting wing and rotor UAV can significantly reduce the aerodynamic interference of rotor wake on wings in hover， and increase flight efficiency. Regarding the continuous tilting transition process of the UAV with complex unsteady aerodynamic characteristics， the delayed detached eddy simulation （DDES） method， improved from the classical detached eddy simulation （DES） method， is used to simulate aerodynamic interference. During the tilting transition process， the aircraft's forward flight speed， rotor pitch angle， fuselage and fixed wing angle of attack， and nacelle inclination angle all dynamically change over time. By comparing with the traditional configuration， the aerodynamic performance changes and flow field mechanisms during the tilting transition process are analyzed. The simulation calculation results show that the UAV in the initial state of tilting is less affected by the rotor downwash. During the tilting process before the 30° nacelle inclination angle， due to the increased resistance of the tilting wing segment， the required thrust of the rotor are increased. The separation vortices generate during the tilting process of the tilting wing section collide with the downwash wake of the rotor， resulting in a larger wake interference area at the wing tip position and a downwash effect on the inner fixed wing tip， reducing the overall lift of the aircraft.

Research on the Interception Capability of Electronic and Firepower Integrated Multilayer Air Defense System Based on Queuing Theory

Qiang GUO, Jinghua WANG, Wei WEI, Tao WANG

2024, 52(3): 20-25. doi:10.3969/j.issn.1009-086x.2024.03.003

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In view of the problem of electronic and firepower integrated multilayer air defense forces interception capability evaluation， regarding the ground-to-air radar jamming system， medium-range air defense missile， short-range air defense missile and antiaircraft weapon as multilayer multi-channel system composed of 4 layers of defense， the interception capability evaluation model of electronic and firepower integrated multi-layer and multi-channel air defense system based on finite waiting queuing system and loss queuing system is established. The example analysis shows that the method can provide a scientific assessment method to the effectiveness of electronic and firepower integrated multilayer air defense system and it can provide reference and basis for optimizing the deployment plan of air defense forces.

Navigational Warfare Capacity System Construction and Development Proposals

Chao YUN, Zhiqiang TAN, Jianyong CUI, Panpan JIANG, Teng ZHENG

2024, 52(3): 26-35. doi:10.3969/j.issn.1009-086x.2024.03.004

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As the role of satellite navigation systems in war continues to improve， it faces an increasingly complex battlefield electromagnetic environment， in order to ensure accurate and efficient transmission of timing and positioning information， and seize the information advantage， the military powers in the world continue to research and develop navigation war-related technology and its equipment， and its successful application to the construction of a new type of satellite navigation system and navigation jamming equipment， to improve the battlefield survivability of satellite navigation systems and the battlefield denial capability of navigation jamming equipment. The navigational warfare related overview and status role are introduced， the capacity status and development trend of navigational war are analyzed in detail， and the suggestions for the development of navigation warfare are given， the relevant research achievements can provide reference for the navigation development.

Analysis on Winning Mechanism and Countermeasure Mode of Anti-submarine Warfare

Zhuo BAI, Bangchu ZHANG, Weiyu ZHU, Pengkun YANG, Yiyong LIANG

2024, 52(3): 36-47. doi:10.3969/j.issn.1009-086x.2024.03.005

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In response to the existing issues of unclear command relationships， ambiguous information flow， and limited means of disposal in anti-submarine warfare， this study proposes mechanisms and modes for achieving victory in anti-submarine operations. It approaches the problem from three perspectives： the physical domain， the information domain， and the intelligent domain. Based on the dynamic and evolving OODA（observation，orientation，decision，action） operational loop theory， combined with an analysis of the current status and trends in anti-submarine equipment and operational styles， a concept design for manned-unmanned cooperative anti-submarine warfare is presented. Additionally， key technological requirements for intelligent domain anti-submarine warfare are summarized， aiming to provide insights for the future development of low-cost and efficient anti-submarine operations.

Tactical Intent Recognition of Complex Air Targets Based on PACA

Xiaocheng SONG, Shuting FENG, Tao JIANG, Zhi LI

2024, 52(3): 48-54. doi:10.3969/j.issn.1009-086x.2024.03.006

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In view of the dynamic nature of air target track， time sequence variation and multiple intentions in battlefield， this paper proposes a recognition method based on end-to-end generic attribute learning， which is used as the basic framework of intelligent multi-intention recognition model. By integrating the time sequence features and attribute characteristics of the target track， the unified input coding information is compressed and modified to encapsulate the knowledge and experience of experts as labels， and the commander's thinking mode of wartime situation judgment is learned to eliminate the interference factors brought by its concealment， deception and confrontation， so as to obtain the complex tactical intention of the specific target. Through the simulation experiment， the common multi-classification evaluation system is used to analyze the influence of the end-to-end training method on the results， and the comparison analysis with the relevant methods shows that the proposed algorithm is more effective and valuable for multi-intention recognition， and can be used to support the establishment of the correlation between non-cooperative targets and defense important places in the combat planning system.

Research and Enlightenment of Artificial Intelligence Defense Technology

Qingtian ZHAO, Liwei LI, Xin CHEN, Lizhi HOU

2024, 52(3): 55-63. doi:10.3969/j.issn.1009-086x.2024.03.007

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The wide application of artificial intelligence technology in the military field has led to the continuous evolution of war forms. To meet the challenge of intelligent warfare， this paper analyzes the development trend and the role of artificial intelligence technology and discusses the necessity of developing artificial intelligence defense technology in the military. From the view of "hard strike" and “soft strike”， the technical ideas of defense against anti-AI weapon systems and AI security defense architecture are given. The technical principles of pollution strike， reverse strike， backdoor strike， and confrontation strike are analyzed emphatically. Suggestions for strengthening AI defense technology research are given from six aspects： top-level design， application review， data governance， primary analysis， command art， and human-machine hybrid intelligence.

Operational Action Identification Method from Knowledge Association Perspective

Wendong ZHAO, Mingzhi ZHANG, Shengming GUO

2024, 52(3): 64-72. doi:10.3969/j.issn.1009-086x.2024.03.008

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The situation data in complex battlefield environment presents large-scale and fragmented features， the knowledge graph technology is applied to situation awareness to recognize operations from the perspective of integrity and relevance. The knowledge graph of operational action is constructed. The situation data such as operational action types， operational forces and attributes are organized in the form of graph to realize the correlation of operational knowledge. An operational action recognition model based on knowledge is designed. The model can fully utilize the attribute information and association information in the graph to enrich the vector representation of entities. By measuring the authenticity of triples， the operational action types and the relationships between combat forces can be recognized. Experimental results show that the proposed method can effectively recognize operations and help the commander to analyze the battlefield situation in depth.

Research on Method of Missile Stability Control Based on Improved PID-LQR Algorithm

Rixin SU, Ou ZHANG

2024, 52(3): 73-79. doi:10.3969/j.issn.1009-086x.2024.03.009

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Missile stability control system is one of the crucial technologies to promote missile guidance performances， and has always been a research hotspot and focus. Taking the longitudinal plane of a missile as an example， a state-space model of the missile stability control is established. The linear quadratic regulator （LQR） control algorithm is derived， and an improved PID（proportional integral derivative）-LQR approach for missile stability control is proposed based on the traditional LQR method and PID algorithm. The control performances of the proposed method are compared with traditional LQR method， improved LQR method， and fuzzy PIQ-LQR method through simulation analysis. The established missile model parameters are subjected to conduct bias tests. The simulation results show that the proposed method is superior to the other three methods and has good control performances and robustness.

Research of Command and Control Model Design Based on Evaluation Model

Qi LI, Qian GAO, Xiaohui SUN, Ning MEI, Feng GUO

2024, 52(3): 80-86. doi:10.3969/j.issn.1009-086x.2024.03.010

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Command and control （C²） models of air defense weapon system such as target threat sequencing， weapon-target distribution and launch decision are lack of comprehensiveness， objectivity and flexibility currently. In order to solve the problems above， a novel command and control model decision method is proposed based on evaluation model. On the one hand， starting from three aspects including design goals， design principles and design methods independently， a design process of factor system which could sort out all influencing factors of the model hierarchically is established. On the other hand， based on the analysis of the characteristics of commonly used evaluation methods， a selection process for evaluation model which could choose appropriate evaluation model is proposed， aiming to realize the evaluation of factor system. In order to verify the performance of the proposed method， this paper uses this method to design a typical air defense weapon system target threat ranking model. The calculation results shown that the proposed method， which could provide a novel solution for the multi-factor decision process of the air defense weapon system， could be used in the design of the command and control model of the air defense weapon system.

Blind Separation of Overlapped Communication Signals Based on Modified Independent Component Analysis

Shunan HAN, Zhulong CHEN, Yongjun LU

2024, 52(3): 87-95. doi:10.3969/j.issn.1009-086x.2024.03.011

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To blindly separate multiple digital band-pass communication signals which are overlapped in time and frequency domains， by using the cuckoo search algorithm， a new separation method is researched based on the independent component analysis. Firstly， the mixed signal model is constructed under uniform linear arrays. Secondly， from the perspective of maximizing the non-Gaussianity of signals， the separation of signals is transformed to the problem of optimizing kurtoses of signals. Finally， the cuckoo search algorithm is used to optimize the cost function which approximates kurtosis. The iteratively generated individuals having the best fitness is regarded as the mix-solving vector and then the source signals are separated. Compared with the existing independent component analysis methods based on fixed-point algorithms， the method in this paper is able to overcome the limitation of its inability to separate the amplitude keying （ASK） signals that are intermixed in the time-frequency domain， and it is applicable to the blind separation of digital bandpass communication signals with any modulation type. The validity of the method is verified and the performance of the method is analyzed through simulation experiments， which show that the separated signals have a high signal-to-inference under the condition of lower signal-to-noise ratio， indicating that the method has high robustness.

A Method for Mining and Analyzing the Association of Air Targets

Xiaorui ZHAO, Hongquan LI, Futai LIANG, Yuzhi QI

2024, 52(3): 96-103. doi:10.3969/j.issn.1009-086x.2024.03.012

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Quickly and accurately mining and analyzing the target association relationship contained in radar historical data can provide assistance for the study of air target activity law， target identification and judgment， and give full play to the role of historical data. According to the space-time characteristics of the target， a new method of mining and analyzing the association relationship of air targets is designed. A time matching method is designed to generate time correlation data sets. A spatial association metric is designed to generate spatial association data sets. Dynamic time warping （DTW） and spanning tree algorithm are used to match and search the air targets with associated relations， and generate the set of associated relations. After digital simulation verification， this method can effectively mine the historical information of radar data and find the correlation rules between targets.

Underwater Image Background and Foreground Segmentation Method with Parallel Convolution

Yongjun TU, Hongsheng LIN, Zhiyong WANG

2024, 52(3): 104-111. doi:10.3969/j.issn.1009-086x.2024.03.013

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Optical detection is an essential tool for underwater detection at short range， while underwater optical images are ineffective for underwater applications due to their low signal-to-noise ratio， low contrast and non-uniform illumination. A common method of underwater optical image processing is background foreground segmentation of the image. There are two main types of methods for performing image segmentation： traditional segmentation methods and deep learning methods. Traditional segmentation methods are susceptible to poor segmentation due to illumination and noise， while common deep learning methods are susceptible to training data limitations and poor generalization. In this paper， a neural network structure with parallel convolution and a constrained loss function are designed， and the optimal values of the hyper-parameters of the loss function are obtained through extensive experiments. The results show that the MAE values of the experimental results obtained by this paper are much smaller than those of FCN8 and UNet， and the mIoU values are larger than those of FCN8 and Unet， and the P-R curves are better than those of other methods， which are more adaptable to the complex and variable characteristics of the underwater environment and can obtain better segmentation results.

Design of Sparse MIMO Array for Near-Filed 3D Imaging

Kang ZHAO, Yan YAN, Jiahao TIAN, Xu HE, Yuzhao LI, Lifeng HUANG

2024, 52(3): 112-119. doi:10.3969/j.issn.1009-086x.2024.03.014

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For the imaging application based on the MIMO array in near-field condition， the sparse array design method is researched. Starting from the radar imaging model in near field， the mathematic model of the sparse MIMO array design method based on the back projection （BP） imaging method is deduced， the theoretical expression of the point spread function （PSF） is derived and the suppression performance of side lobe is analyzed. Two sparse array design methods are given for multiple targets imaging verification at the same time. It can be seen from the simulation results that the designed sparse MIMO array can meet the needs of near field imaging and provide a foundation for real application.

Active Radar Deception Jamming Recognition Based on Multi-dimensional Wavelet Features

Yibing LIU, Qiang LUO, Ran HU, Linlin FU

2024, 52(3): 120-127. doi:10.3969/j.issn.1009-086x.2024.03.015

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According to the identification of radar active deception jamming in tracking mode， by analyzing radar signal and jamming models， we propose a recognition algorithm based on multi-dimensional wavelet features. The signal is sampled and accumulated within the first pulse repetition interval among multiple coherent processing intervals of the target echo to constitute a one-dimensional discrete sequence and the multi-scale wavelet coefficients are extracted using the Mallat algorithm. The shift correlation coefficients of wavelet coefficients at different scales are computed to constitute eigenvector for recognition. Constructing signal samples with different parameters for simulation， the recognition accuracy is still higher than 80% at the signal-to-noise ratio of -5 dB， and the algorithm can effectively distinguish between the range false target and the range gate pull off jamming， which proves the accuracy， versatility and preciseness of the algorithm. Moreover， for the actual situation， we can adjust the dimensions of eigenvector， and select more suitable mother wavelet to further optimize the jamming recognition result.

Research on Jamming Mechanism of Instantaneous Frequency Measurement

Lei WANG, Honglei WANG, Hongxun WANG, Xinmiao LIN, Zixiang XIONG

2024, 52(3): 128-136. doi:10.3969/j.issn.1009-086x.2024.03.016

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IFM （instantaneous frequency measurement） system is an important reconnaissance resource in electronic reconnaissance. It can quickly determine the frequency of the signal to be measured， has good real-time performance， wide frequency range and high frequency resolution， and can also indicate the signals of simultaneous arrival in the case of multiple signals. It's very widely used. Based on the characteristic that IFM microwave phase discriminator can only respond to one signal at a certain instant， combining with the working principle of IFM， a new （more than 2 signals） interference strategy to IFM is investigated and the interference mechanism is analyzed， and the interference effect of IFM is evaluated through analog simulation. The simulation results show that the overlapping of multiple signals can produce obvious jamming effect on the IFM system， which can make it unable to measure the correct frequency， and the wrong output reaches the signal indication at the same time.

Research on the Evaluation Method of Launch Flight Reliability of Missile

Jiaxi CHEN, Yuhao WANG, Chen CHENG, Xiaorui YUE

2024, 52(3): 137-142. doi:10.3969/j.issn.1009-086x.2024.03.017

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Launch flight reliability is an important tactical index of missile. Considering that the flight test data cannot meet the high reliability requirement of missile， this paper proposes a missile reliability evaluation method based on reduced factor Bayes theory， by integrating the ground data. This method first converts the ground test data and the consistency check is carried out； then， using L-M method to convert ground data into prior information of missile flight test. Finally， the lower limit of missile launch flight reliability is evaluated based on the reduced factor Bayes theory. The results of a typical case study show that the proposed method can make full use of reliability evaluation data of the missile and its subsystem， which not only reduces the cost and risk of flight test， but also increases the rationality of the missile launch flight reliability evaluation.

Application of Quick Hull Algorithm in State Monitoring for Missile Launcher

Yan YU, Pengying BAI, Xuefeng ZHANG

2024, 52(3): 143-150. doi:10.3969/j.issn.1009-086x.2024.03.018

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Aiming at the problem that there are too many false alarms in the current state monitoring strategy of complex industrial systems， a method to detect working state of missile launcher based on the quick hull algorithm is proposed. The normal working space is estimated from given historical normal data points. For a new-collected data point which reveal working state of missile launcher， if it is inside the established normal working space， the missile launcher is in the normal condition and no alarms are raised； otherwise， the missile launcher is in the abnormal condition and alarms will occur. Compared to static thresholds， the proposed method will cause fewer false alarms. The proposed method does well in explanation compared to the latent variable based methods. A two dimensional and three dimensional cases are analyzed by numerical simulation to evaluate the performance of the proposed method. The simulation results show that the physical meaning of the proposed method is clear and the number of false alarms generated is small.

Research on Application of Unknown Fault Prediction Considering CapsNet Algorithm

Bowen CUI, Xiaochuang TAO, Yanbin YUAN

2024, 52(3): 151-158. doi:10.3969/j.issn.1009-086x.2024.03.019

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Aiming at the problem that the existing fault prediction model does not have the ability to identify unknown faults， it is necessary to re-collect data to train the model or learn and identify unknown faults with the help of other components， an unknown fault prediction method based on the CapsNet model is proposed. This method can effectively process the multi-dimensional state sensing signals of complex equipment， realize the accurate sensing of equipment faults， and adaptively adjust the model and predict unknown faults when unknown faults occur. The conversion matrix is constructed to predict the existence and posture of the corresponding high-level features from the features of the low-level capsules. The process by which the dynamic routing algorithm integrates the prediction vector generated by the low-level capsule into the high-level capsule that agrees with it and forms the feature vector is described in detail. In the process of implementing fault feature classification in the last layer of CapsNets， a threshold judgment method is proposed. By reasonably selecting the value range of the threshold， the capsule network model can perfectly distinguish between known and unknown faults and realize accurate fault prediction. The proposed method is used to verify the performance of a series of well-trained CapsNets models. Through experiments， it can be found that the proposed method can better realize unknown fault prediction， which can prove the feasibility of the method.

Research on Friction Torque Test Technology of Jet Vane's Manipulator

Qiang QIN, Min HU, Jingshuai CAO, Ang LI

2024, 52(3): 159-169. doi:10.3969/j.issn.1009-086x.2024.03.020

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In order to efficiently and accurately evaluate the friction torque of the jet vane's manipulator under the laboratory conditions， a test system for the friction torque of the jet vane shaft bearing is designed. On this basis， a test system for the friction torque of the manipulator is further built to fully simulate the actual installation state of the jet vane system， and then a test method for the friction torque is proposed， the variation trend of the key bearings friction torque with the load and overload coefficient are revealed， and the key factors affecting the friction torque of the manipulator are explored. The test results show that the test system provides a reasonable test method for accurately obtaining the friction torque. The friction torque of the key bearings of the rudder shaft increases with the rise of the load and overload coefficient， and the bearing friction torque plays a leading role in the friction torque of the manipulator.

Influence of Current Time Harmonic on Electromagnetic Vibration of Permanent Magnet Synchronous Motor

Chenghao KOU, Shu WANG, Xuelei ZHANG, Zhengyu LIU, Zuxu GUO

2024, 52(3): 170-179. doi:10.3969/j.issn.1009-086x.2024.03.021

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In order to reveal the influence of current time harmonics on the electromagnetic vibration and noise of the motor， the radial electromagnetic force of the permanent magnet synchronous motor （PMSM） fed by frequency converter is analyzed and calculated with Maxwell stress equation， the order and frequency of radial electromagnetic force are analyzed theoretically. It is pointed out that the electromagnetic vibration and noise produced by the motor in low frequency and middle-high frequency can be aggravated by the power supply of the inverter. Taking a 48-slot 8-pole permanent magnet synchronous motor as an example， the electromagnetic finite element model and structure finite element model of the motor under the condition of inverter and sine wave power supply are established respectively. The vibration response and noise change of the motor under these two power supply modes are compared by ANSYS multi-physical field simulation， and the correctness of the analytical analysis is verified.

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