Abstract:The existing concept of aircraft structural integrity has been evolved under the conditions that the aircraft was in normal use. Operational use is the fundamental function of military aircraft. The traditional concept of aircraft structural integrity has some limitations, and it is not suitable for military aircraft in operational phase. Through the improvement and deepening of the traditional concept of aircraft structural integrity, concepts of military aircraft openational integrity, recoverability and military aircraft structural openational integrity are put forward in this paper, and the connotation of the military aircraft structural operational integrity is expounded. Finally, the evaluation methods of military aircraft structural operational integrity and the related test methods involved in the evaluation are discussed.

Abstract:n order to establish a dynamics model of the diamond jointedwing configuration UAV, a dynamics modeling method based on Lagrange’s equation is proposed. Firstly, the quaternion is selected to parameterize the attitude of the UAV, and the constraint matrix of the UAV system is established. Secondly, a generalized force matrix of the UAV is established by the virtual work, the Kinetic and Potential energy of the UAV are established. Finally, a matrix is obtained by the concept of matrix direct product and the product of this matrix and the constraint matrix is a zero matrix. The Lagrange multipliers in the Lagrange’s equation are eliminated by the matrix, and the dynamics model of the UAV is established in modularization based on the Lagrange’s equation. In order to compare with the Lagrange’s equation, the Kane equation and ADAMS software are also used to establish a dynamics model of the UAV. The results show that the simulation of Lagrange’s equation, Kane equation and ADAMS software are basically the same, and the rationality of the dynamics modeling in this paper is verified.

Abstract:Aimed at the problems that the data are insufficient in manufacture, the risk factors are comparatively complex and the dynamic effect is significant, an improved model combined hierarchical holographic model (HHM) with Bayesian network (BN) is proposed. The risk identification framework of engine fuel accessories manufacturing is constructed by HHM. On the basis of this, the BN model is built, and its parameter learning method of maximum likelihood is improved. Finally, the effectiveness is verified by the example and Netica software. The results show that the total risk value of the engine fuel accessories manufacturing is 25%, and the key risk factors are dynamic balance and 302 hole lapping.

Abstract:In view of realizing an advanced power plant by using aviation kerosene to meet the needs of regenerative cooling, a threedimensional numerical model of fluidthermalstructural coupling in the rectangular cooling channel is established, and the influence of working conditions, such as inlet flow mass rate, pressure and heat flux density on the flow and heat transfer characteristics of aviation kerosene in the rectangular cooling channel is analyzed. The results show that increasing the mass flow rate and reducing the heat flux density will definitely enhance the heat transfer ability of aviation kerosene. Within the range of a certain pressure, the influence of pressure on aviation kerosene heat transfer is not obvious, but with the increase of pressure, the heat transfer ability of aviation kerosene becomes worse. Due to the occurrence of heat transfer deterioration, the influence of the working conditions as mentioned above on the pressure loss and the friction resistance is comparatively complicated

Abstract:For the convenience of studying the influence of serration on the electromagnetic scattering, two aircraft models with straightline and serration mouth inlet are established taking two kinds of flying wing layouts as a basis. The RCS curves with different parameters are calculated numerically by the Physical Optics method. And the effect of serration on scattering distribution and the RCS reduction with different pitch angles frequencies are studied. The numerical results show that the serration mouth inlet can effectively reduce the scattering peaks in nose and rear direction, and also affects the distribution of peak in other angular domains. The RCS reduction decreases in oscillation with amplitude variation from 10~30dB when the pitch angle increases. The RCS reduction varies in oscillation with amplitude variation from 5~25 dB when the frequency increases. The serration has an effects differently on the electromagnetic scattering with different layouts. The stealth performance of layout A in angular domains of 30° in nose direction is improved obviously, and the reduction value is 20~30 dB.

Abstract:Aimed at the problems that the degree of freedom in the current nested MIMO array (Multiple-Input Multiple-Input Multiple Output Multiple Array) is limited, an optimized nested array is proposed, i.e. to optimize the nested MIMO array design. This method not only retains the original advantage of nested MIMO array design-closed expression with array element position and degree of freedom, but also greatly improves the array aperture and degree of freedom (DOF). Firstly, the optimized nested array is used as the transmitting and receiving arrays, and then the difference between the MIMO arrays is processed to obtain the difference array of array elements. By properly designing the array spacing of the transmitting and receiving arrays, a non-porous difference matrix can be obtained. When the total number of array elements is given, by analyzing the characteristics of the array structure, the best array element number of the transmitting and receiving arrays can be obtained. The simulation experiments show that compared with the nested MIMO array design, the proposed method can effectively expand the array aperture, increase the degree of freedom, and increase the DOA estimation accuracy of the MIMO radar under condition of non increasing the number of actual array elements.

Abstract:To solve the problems that the narrowband radar range is low in resolution and is hard to separate trajectory group targets from range dimension, a method of separating group target signal components by using Discrete Sinusoidal Frequency Modulation Transform (DSFMT) is proposed. The modulation characteristics of micromotion ballistic target echo are studied and an echo model of micromotion signal is established. The energy aggregation characteristics of DSFMT are used to project multicomponent signal into transform domain. The objective function of parameter estimation is constructed to process the peak feature points in the transform domain, and the signal components are separated step by step. The effectiveness and robustness of the algorithm are verified.

Abstract:Aimed at the problem that the utility of the traditional decorrelation algorithm to the array aperture is poor, this paper proposes an improved spatial smoothing algorithm. All the data information of the covariance matrix received signals are utilized fully by reconstructing subarray covariance matrix, and the spatialdifferencing matrix is built to suppress the effect of noise. Finally, the propagator method algorithm is adopted to estimate 2dimensional direction of arrival (DOA). The simulation shows that this algorithm is good in decorrelation algorithm, and high in computation precision compared with the traditional decorrelation algorithm.

Abstract:Aimed at the problem that singular value decomposition for singlechannel is poor in the effect on strong noise, a noise cancellation method based on dualchannel singular value decomposition is proposed. Firstly, the method of singular entropy determination is used to preprocess the noise component of high order, then the position of the low order singular vectors of the noise is determined from the correlation of the dualchannel singular vectors, and finally, the residual singular values and corresponding singular vectors are reconstructed to obtain the optimized estimated noisefree signal. The simulation experiments show that by the proposed method compared with the conventional method under condition of the low SNR and the white noise environment, the SNR gain increases by 4.07 dB and waveform correlation coefficient increment of pure signal increases by 0.11. On the other hand, a voice signal contaminated by cockpit noise is chosen as the experimental object. Compared the proposed method with the adaptive noise cancellation method for dualchannel, the results show that the SNR gain increases by 4.83 dB, and the operation takes a 1.5 s shorten. In addition, the proposed method is not restricted by the noise type, and also has a good adaptability to the colored noise, the singlefrequency interference and even the mixed noise, and a broad application prospect.

Abstract:Aimed at the problems that in the face of the increasingly complex electromagnetic environment, the feature recognition algorithm for the blind source separation of multifrequency hopping signals is heavy in computation, and the separation result is inaccurate, in combination with the variable speed frequency hopping signal, a strategy of accelerating the hopping speed and varying the hopping speed is adopted. Simultaneously the independent component analysis method is utilized for dealing with the blind separation problem of variable speed frequency hopping signals, and the negative entropy maximization algorithm is used to accelerate the separation speed of traditional independent components. The simulation results and actual frequency hopping data show that compared with other methods this algorithm can effectively separate the multiple variable speed frequency hopping signals without any prior information and low SNR. At the same time, the time domain waveform of the variable frequency hopping signal and the corresponding frequency hopping pattern can be accurately recovered, in the case of 20 dB SNR, the separation similarity coefficient can reach 99%. The analysis mentioned above provides a new solution for the blind separation problem of the variable frequency hopping signal.

Abstract:In order to alleviate the problem of excessive noise and excessive power consumption introduced by longdistance transmission of highfrequency clock signals in multichannel SerDes, a lowpower lowjitter twostage phaselocked loop applied to multichannel serial interface is designed, Simultaneously, this design is used to transmit the lowfrequency clock signal (3.125 GHz) generated by the firststage LC oscillator phaselocked loop to each channel transceiver, this signal is taken as the secondlevel reference signal, and then a smallarea ring oscillator phaselocked loop is used to produce an orthogonal highfrequency clock (12.5 GHz). This structure reduces the distance that the highfrequency clock transmits over long distances on the chip, and improves the clock quality of the transceiver. In addition, this technology avoids the use of highfrequency buffers and reduces power consumption. In order to further reduce the noise performance, a sampling phase detector is designed in the secondstage phaselocked loop. This technology improves the noise performance of the secondstage ringvibration phaselocked loop by means of nofrequency phase discrimination. The overall power consumption of the clock generator circuit is 100 mW, the phase noise of the firststage phaselocked loop is -125 dBc/Hz, and the phase noise of the secondstage ring oscillator circuit is -79 dBc/Hz at 1MHz. The overall jitter of the clock signal generated by the circuit is 2.7 ps. The quadrature clock skew is within 300 fs.

Abstract:With the rapid development of control technology of electromagnetic wave propagation, frequency selective surface (FSS) has become the hotspot of attention and research due to its special spatial filter characteristics. Up to now, FSS has found wide applications in the fields of electromagnetics. The progress of FSS is firstly presented, and the applications of FSS in Antennas and Microwave Technology are discussed, Finally, the development of FSS is looked forward to the future.

Abstract:In view of collocated MIMO radar tracking multiple moving targets, this paper proposes a power allocation method based on the Posterior CramerRao Lower Bound(PCRLB). In this method, firstly, the PCRLB of multiple moving targets localization localization errors is given as a cost function for power allocation. Thus, the radar power allocation is transformed into a convex optimization problem. Then, the SDP algorithm is used to deal with the convex optimization problem to transform it into a SDP problem and solve, realizing the optimal allocation of radar power. Finally, the validity of the proposed algorithm is verified by simulation. The results show that compared with the average power distribution and a greedy algorithm based on maximum SNR, the tracking accuracy of the target is obviously improved by the optimal power distribution method.

Abstract:In view of the problem of the existing methods of lowresolution radar target recognition, usually the twostep recognition algorithm is adopted to make feature extraction and target classification, which is not conducive to the improvement of recognition accuracy and the generalization of recognition methods, for the reason mentioned above, an onestep recognition algorithm based on Convolution Neural Network (CNN) for lowresolution radar target is proposed. This algorithm takes the sampled data as input directly, and uses the designed onedimensional CNN to automatically obtain the deep essential features of the data without feature extraction through convolution pooling and other operations, realizing the onestep recognition of the target. The simulation results show that the recognition rate of the onestep recognition method is 10.31% higher than that of traditional twostep recognition method based on artificial feature extraction, and the recognition time of onestep recognition method is 0.142s less than that of twostep recognition method, which proves the effectiveness of onestep recognition method. The onestep recognition method provides a new solution for radar target recognition.

Abstract:Threat assessment is an integral part in air combat. In order to accurately describe the threat degree of multiple targets, firstly, according to the threat indicator model, combined with the genetic algorithm and analytic hierarchy process (AHP), a GAAHP algorithm is adopted to establish the consistency indicator function through the threat judgment matrix, and the problem of solving the eigenvector is converted into the problem of solving the consistency ratio. Secondly, through adjusting the parameters of the algorithm and comparing with other methods, the optimal feature vector is selected according to the consistency ratio. Finally, based on the index threat function and taking the multi-target air combat environment of 2v4 as the background, the target threat value of each index is calculated, and the multi-target threat ranking is obtained according to the optimal eigenvector. The experiments show that the GAAHP algorithm can produce more optimized consistency index value and eigenvector, and accurately describe the threat degree of multiple targets.

Abstract:NDN security mechanism lies in the information itself, and the effective signature and encryption must be given to the data transmitted in NDN , otherwise the attacker can get data or send them at will. In view of this security problem, a lightweight encryption algorithm is designed. The meaning and purpose of the each step of the algorithm and security under various attack modes are analyzed in detail. The algorithm is optimized to improve its efficiency and is embedded in ndnSIM for simulation. The verified data are transmitted in encrypted way from the publisher and the identity of the publisher can be verified correctly after receiving the data, and the change of plaintext and the verification data can be correctly solved. The effect of the algorithm on confidentiality，authentication , integrity and efficiency are verified.

Abstract:In view of network business security risk assessment problems, a STRIDEHMM network risk assessment and prediction method based on STRIDE threat modeling and HMM theory is proposed. Taking the network service as an entry point, the construction method of the task description model, the task asset model and the task risk assessment model and the relationship are given among them. The task description model gives the task phase partitioning and corresponding asset sets, vulnerability sets, and threat sets; The task asset model gives a set of assets depended on each stage of the task. On the basis of this, HMM is used to give the quantitative calculation method of asset security status. The task risk assessment model realizes the risk assessment for network business by using aggregation analysis method to achieve the task risk value calculation method according to the results of the asset classification set. To verify the effectiveness of the proposed method, a typical web application example of assets, vulnerabilities and threats combined with threat modeling tool TMT is given. The result proves that the proposed method can provide decision support for the security planning and scheduling oriented to the needs of tasks.