2020, 21(2):1-15.
Abstract:At the moment, information transmission is mostly transmitted by adopting the traditional RF data link among the aviation platforms. Whereas the RF data link remains a lot of the problems that transmission rate is low, RF resource is limited and easy in interference, and easy to be intercepted. Such inadequate resources are hardly to meet the needs of the development of space exploration, the highspeed transmission, the interconnection and sharing of the spatial information transmission and the expanding application in the military field. and development demanding to the highspeed data transmission and information security of the aviation platform. Therefore, by using the characteristics of the aviation platform in the aspects of information acquisition, transmission and distribution, a highspeed transmission, a safe and reliable air platform communication link is established, and the networking application of the aviation platform is further realized, which is the basis for ensuring the safe and reliable transmission of the spatial information network data. highspeed transmission of data information in military fields such as airspace security, longrange combat and command and control. Optical communication among aviation platforms is characterized by the high speed, large bandwidth, antiinterference, good confidentiality, miniaturization of terminal, and so on. Such an optical communication has advantages in reliable transmission of aviation platform and military confidentiality applications,and can not only break through the restrictions of ground command and control center on aviation platform, but also effectively improve the technical disadvantages of traditional RF data links in bandwidth, antielectromagnetic interference and stealth transmission. The mentioned above subject is an important research field and development direction of future spatial information network to use aviation optical communication technology to realize highspeed data transmission between machines in the future, and to construct aviation information network with interconnection and information sharing.
WANG Xiaoping , ZHOU Wen , LIU Bo
2020, 21(2):16-23.
Abstract:Aimed at the problems that an early warning aircraft is limited in maneuverability and is also subject to the “targeting dagger” threat of enemy advanced missiles in air combat, an active defense method is designed. First, an early warning aircraft or escort aircraft is to launch one or more defense missiles to combat incoming missiles. Second, the early warning aircraft is to evade them under condition of battlefield perception, information sharing and tactical coordination. Based on the research of the optimal cooperative guidance algorithm with the optimal control theory in the threebody attack and defense confrontation problem composed of target aircraft, defensive missiles and target missiles under the twodimensional plane, the cooperative guidance law is extended from twodimensional to threedimensional through twodimensional projection method for active defense process in threedimensional space which transforms the design problem of the threedimensional active defense guidance law into two mutually constrained twodimensional plane guidance law (horizontal and vertical plane) design problems. The simulation results show that the proposed guidance algorithm can effectively intercept the incoming missiles under different attack modes in space and meet the needs of interception accuracy. The simulation results show that compared with the traditional interception guidance algorithm, the proposed guidance algorithm not only meets the required interception accuracy, but also has a smaller interception overload and has certain advantages.
JIANG Zihan , WANG Zhuojian , YU Huan , LI Yuan
2020, 21(2):24-28.
Abstract:With military training intensity being comprehensively improved, there are dangerous oil leakage, and cracks in hydraulic duct of fighter jet, these phenomena threaten to flight safety. Aimed to the problems thatthere are some mismatches between the fatigue life on the rear fuselage hydraulic conduit and the life of the body structure, this research is focused on one main influence factor, the assembly error. At the start of the fatigue life analysis of random vibration load, applying digital modeling methodology to develop the typical pipeline model, based on the Miner linear cumulative damage theory, the fatigue calculation program is developed by finite element analysis software to simulate and evaluate the fatigue life of normal assembly hydraulic conduit. Based on the influence of assembly stress on fatigue life, the pipeline model is adjusted to simulate different assembly errors, and the fatigue life of hydraulic ducts with different assembly errors is analyzed by using structural dynamics theory and fatigue calculation program. It follows that when the assembly error is greater than 0.73 mm, the fatigue life of the hydraulic duct will be lower than the airframe life of 3000 flight hours, i.e. seriously threatening flight safety. The research results provide technical support and experience reference for the further research on the theory of aerohydraulic pipe assembly.
LIANG Hua , HE Qikun , WEI Biao , YANG Hesen , SU Zhi , XIE Like
2020, 21(2):29-35.
Abstract:Being a new type of active flow control technology, the plasma flow control can significantly improve the aerodynamic performance of aircraft. In this paper, the flow separation control of a UAV is studied by nanosecond plasma aerodynamic excitation. The experimental results show that the nanosecond discharge and the millisecond discharge are almost equal in excitation voltage, but the current generated by nanosecond discharge (30 A) is much larger than that generated by millisecond discharge (0.1 A). The induced effect of nanosecond plasma is similar to an upward shock wave produced in the flow field, and the maximum induced velocity is less than 0.5 m/s. The rapid temperature rise effect of nanosecond discharge induces a shock wave in the still air. The shock wave lasts about 80 microns and travels at a speed of about 380 m/s. Withthe nanosecond plasma aerodynamic excitation being used, when the excitation voltage is greater than a certain threshold value, the flow separation on the suction surface of the UAV can be suppressed. The critical stall Angle of attack can be increased from 20° to 27°, and its maximum lift coefficient increases by 11.24%. Furthermore, the optimal excitation frequency of nanosecond plasma aerodynamic excitation is the value to make the dimensionless numbers 1. In the boundary layer flow control, the nanosecond plasma aerodynamic excitation is more effective than the millisecond plasma aerodynamic excitation. The main mechanism of nanosecond plasma flow control is impact effect. The impact effect is more effective than the dynamic effect in highspeed flow control.
GAO Peng , WEI Wei , LIU Xi , GONG Xiangrui , FENG Lei
2020, 21(2):36-40.
Abstract:In order to overcome the "frequency ambiguity" phenomenon by using the traditional Fast Fourier Transform to analyze signals of equipment under the condition of varying rotating speed, this paper presents an order analysis method without phase signal. Firstly, the variation range of rotation speed is estimated by equipment control system or other ways to confirm the filter range; secondly, narrow band filtering is filtered off from the signals; Thirdly, the instantaneous frequency is calculated by Hilbert Transform; Finally, the stationary signal in angular domain is obtained by resampling the timedomain signal according to instantaneous frequency, and then the order spectrum is made by Fast Fourier Transform. The validity and accuracy of the order analysis method are verified by the simulation signal. Then, the method used to extract the amplitude of sinusoidal component of signal under variable rotating speed condition is applied in analyzing equipment signals in UAV, laying a foundation for accurately setting up the environment condition of equipment. The method in this paper is an effective supplement to the signal order analysis, and its application has reference value for the evaluation of dynamic environment of similar equipment.
LU Jianqi , NAN Jianguo , LI Xue
2020, 21(2):41-46.
Abstract:Aimed at the problems that the life time of nodes is limited, and the delivery rate is low in the cluster network because the platform of miniature military drone is small in size, the drone is high at speed, and the energy is limited, this paper proposes a wireless Ad Hoc network routing algorithm (DijkstraCompound Weight Routing Algorithm, DijkatraCWRA) with compound weight by referring to the greedy algorithm. In order to reduce the influence of edge nodes and lowenergy nodes on the path, two optimization parameters, boundary evaluation factor and energy balance, are added to the algorithm to screen the nodes, and the idea of Dijkstra algorithm is used to find the forwarding path with the minimum energycongestion compound weight in the network for data transmission. The simulation results show that compared with the AODV algorithm and the AOMDV algorithm, the proposed algorithm has good performance in aspects of the delivery success rate, the endtoend delay, the network lifetime and the routing overhead.
JIANG Guojian , GONG Zhihua , LIANG Ting , LI Kaiming , ZHANG Qun
2020, 21(2):47-52.
Abstract:Aimed at the problem that the existing micromotion feature extraction method is unapplicable under the condition of the scattering coefficient of the complex timevarying, this paper puts forward a kind of micromotion feature extraction method based on timevarying 3D image coordinate reconstruction. By the use of this method, firstly, the micromotion signal model of the rotating symmetric space cone target is established, then the scattering points are separated by dynamic programming to obtain the timevarying threedimensional image of the target after the phase interference of each scattering point. And finally, the 3D micromotion feature of the target is extracted by using highprecision 3D coordinate reconstruction. The simulation results show that the accuracy of the proposed method is better than that of the traditional method. The proposed method can be well applied to the case of complex timevarying scattering coefficients.
ZHAO Chenhao, WU Dewei, HE Jing, HAN Kun, LAI Lei
2020, 21(2):53-60.
Abstract:In order to improve the efficiency in navigation cognitive mapping and reduce the error of direction information, a method of navigation cognitive mapping based on improved Q-learning algorithm is proposed in this paper. Firstly, Radial Basis Function (RBF) neural network is utilized for trainning the mapping relationship between grid cells and place cells, and the place cells are used to convey space information. Secondly, the improved Q-learning algorithm is used to learn the targetoriented Q-value of the place cell to obtain direction information towards target. Finally, the center of gravity estimation principle is used to generate the targetoriented direction information, constructing the navigation cognition map. The simulation results show that learning rounds of the navigation cognitive mapping generated by this algorithm is reduced from 2 000 to 1 000 compared with the traditional Q-learning algorithm, improving the construction efficiency of navigation cognitive map. Meanwhile, a maximum reduction of 15% in relative error is achieved, improving the precision of navigation cognitive mapping.
CHEN Geng, TIAN Bo, GONG Jian, FENG Cunqian ,
2020, 21(2):61-64.
Abstract:The purity of reference data affects the detection capability of DTMB passive radar, and the accuracy of reference channel estimation is a key factor to affect the recovery of reference data. In view of this problem, the channel estimation method based on the deep learning theory is introduced into the passive radar reference channel estimation process. The reference channels are modeled by the autoregressive model and the reference channel estimation network is built. After iterative training, the reference channel response is estimated. Compared with the traditional algorithm, the estimation accuracy of reference channel based on deep learning is improved effectively, and the detection performance of radar is improved.
XU Chenlu , HAO Shiqi , WANG Yong , ZHAO Qingsong , LIU Yujie
2020, 21(2):65-70.
Abstract:The wavefront phase distortion should be expanded into different orthogonal polynomial combinations for wavefront reconstruction based on modal method. Different orthogonal bases represent different modes of wavefront phase distortion caused by atmospheric turbulence. By calculating the mutual information between the wavefront distortion caused by atmospheric turbulence and each mode, the influence degree of different modes on wavefront distortion is analyzed,and the wave front reconstruction is made in accordance with the established new reconstruction matrix of the mutual information from large to small. The numerical simulation results show that when only one mode is adopted to correct the wavefront, the RMS of the wavefront residual based on mutual information reconstruction decreases from 1.8 rad to 1.15 rad, and the RMS of the traditional mode reconstruction method only decreases to 1.74 rad. When the two modes are adopted to reconstruct the wavefront, the RMS of the residual wavefront of the two methods decreases by 1.2 rad and 0.1 rad respectively. When 65 modes are adopted to reconstruct the wavefront, the traditional mode method has a wavefront residual of 0.2 rad, and when the wavefront residual based on mutual information reconstruction is 0.2 rad, and only 18 modes are needed. Compared with the traditional modal method under conditions of the same precision of wavefront reconstruction, the number of reconstruction modes required for wavefront reconstruction based on mutual information is greatly reduced, reducing the complexity of the reconstruction matrix and improving the speed of wavefront reconstruction.
HE Tuan , TANG Bo , ZHANG Yu , YANG Yanwei
2020, 21(2):71-77.
Abstract:Aimed at the problem that the high computational complexity of airborne multipleinput multipleoutput(MIMO) radar spacetime adaptive processing (STAP) technique exists in using the sparse method to recover the clutter spectrum, a dictionary dimension reduction method is proposed. In this method, the training samples are directly used to estimate lowresolution clutter spacetime spectrum. On this basis, the resolution of spectrum is improved by using the iterative formula of FOCUSS algorithm. Then the Capon spacetime power spectrum values of each atom are calculated and the atoms with large spectral values are selected to form the reduceddimension dictionary. When there is doppler ambiguity, the prior knowledge is used to exclude the atoms selected because of doppler ambiguity, and the remaining atoms met the requirements are taken out to form the reduceddimension dictionary. The simulation results show that the reduceddimension dictionary can completely cover the clutter ridge, and simultaneously can effectively improve the operation efficiency while maintaining the SINR output performance of the algorithm.
HAO Zhili , LIU Chunsheng , ZHOU Qingsong
2020, 21(2):78-83.
Abstract:The transceiver isolation of jammers on small platforms such as UAV is the key to affect the simultaneous operation of transceiver. As for the dynamic sparse systems, the conventional Kalman filter (KF) algorithm does not consider the sparsity of the coupling paths of interference signals, and the identification accuracy of paths attenuation coefficients are not enough, so that the isolation performance is poor. Aimed at the problems that starting from the correction step of KF algorithm and regarding this as equivalent to a convex problem, on the basis of this, the sparse constraints on estimated parameters are added, the correction steps of the algorithm are deduced again, and a KF algorithm with sparse constraint (SC) is proposed, by so doing, this makes full use of the prior information of the system to be identified and improves the sparse tendency of estimated parameters. The theoretical analysis and the simulation results show that the new algorithm can effectively apply to the system identification in the dynamic sparse environment, and improve the identification accuracy of KF algorithm for the dynamic sparse system. Moreover, the isolation degree of transceiver of jammer can be improved by 3~5 dB, improving the isolation performance of jammer.
DONG Pengyu , WANG Hongwei , CHEN You , JU MING
2020, 21(2):84-90.
Abstract:Recognition of radar emitter signals is one of core elements in radar reconnaissance systems. In order to attain a higher correct recognition rate of radar emitter signals under condition of low signaltonoise (SNR) ratio, a novel method based on Main Ridge Slice of Ambiguity Function (MRSAF) and Deep Belief Network (DBN) is presented. Firstly, the singular value decomposition (SVD) is preprocessed for noise reduction, and then this paper calculates the AF of the sorted signal and ascertains the main ridge slice envelope. To improve the recognition performance, the SVD is employed to eliminate the influence of noise on the main ridge slice envelope. A DBN model is established on the stacked Restricted Boltzmann Machines (RBM) and the labeled data with the supervisory finetuning model parameters are used to complete the training. Finally, the model is used to achieve the radar emitter signals recognition and classification. The simulation results indicate that the novel algorithm provides significant performance and the validity and application value of this algorithm are verified. Compared to the existing methods, the novel method can achieve a higher correct recognition rate even at a low SNR.
XU Yuheng , CHENG Siyi , ZHOU Yipeng , SUO Zhongying , PENG Shuming
2020, 21(2):91-96.
Abstract:Aiming at the problem of radiator threat evaluating in radar countermeasures field, an objective weight distribution method based on Shapley value is used to overcome the advantages of subjective assignment and not relying on prior knowledge. Combined with TOPSIS(Technique for Order Preference by Similarity to an Ideal Solution), a radiator threat assessment model based on ShapleyTOPSIS is proposed. Firstly, the evaluation matrix of target set and attribute set is constructed by distinguishing benefit type and cost type and standardize the attribute indexes. Then, the advantage relation is used for attribute reduction, and the weight of each attribute is determined based on Shapley value, and the attribute weight is used to update the evaluation matrix. Finally, the positive and negative ideal solutions of the model were obtained, and the proximity degree of each radiator was solved respectively, and the threat ranking of radiator was conducted. The simulation results show that, compared with TOPSIS model based on expert system assignment, the model in this paper comprehensively considers the relationship between various attributes, and the result of threat ranking is more accurate.
HUANG Lin , YUAN Xiujiu , ZHAO Xuejun , ZHENG Mingfa
2020, 21(2):97-105.
Abstract:In order to quantitatively characterize the degree of uncertainty of hesitant fuzzy information, the entropy of hesitant fuzzy element and intervalvalued hesitant fuzzy element are generalized to the entropy of hesitant fuzzy sets and intervalvalued hesitant fuzzy sets. First of all, the axiomatic definitions of entropy and similarity measure of hesitant fuzzy sets and intervalvalued hesitant fuzzy sets are given. On this basis, a generalized formulae of entropy and similarity measure is proposed. The algorithms for generating entropy and similarity of hesitant fuzzy sets are given. Then, the relationship between the entropy and the similarity measure of the hesitant fuzzy sets is studied, and the generalized similaritybased entropy formulae are proposed. Furthermore, the relevant conclusions of the relationship between the entropy and the similarity of the hesitant fuzzy set and their respective general formulas and generating algorithms are extended to that of intervalvalued hesitant fuzzy sets. Finally, a numerical example of the reliability analysis of the logistics supply base location scheme based on the entropy and similarity of hesitant fuzzy sets is given.
ZHANG Jianhang , CAO Zeyang , SONG Xiaofeng , XING Lipeng
2020, 21(2):106-111.
Abstract:Aimed at the problems that the homomorphous signature schemes based on the latticebased theory can resist the quantum computer attacks, however, the existing homomorphous signature schemes based on the standard latticebased theory are inefficient due to their large key storage and complex structure, failing to be used for the equipment support cloud service, a first antiquantum computing linear homomorphism authentication scheme for equipment assurance cloud service is designed based on the NTRU. The algorithm generated by the key of the NTRU is utilized for simplifying the system key quantity and avoiding the huge key quantity. And then the linear homomorphism authentication value is produced by using the simple structure of the NTRU lattice preimage sampleable algorithm. The results show that the scheme satisfies the weak context hiding property. And the scheme achieves existential unforgeability against adaptive chosen message under the NTRUSIS (small integer solution) assumption in the random oracle model. Compared with the current scheme in effect, the new scheme is superior in the key quantity, the certification cost and the communication cost.
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