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2013 Vol. 39, No. 5

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Adaptive BTT terminal guidance law for hypervelocity vehicle
Li Huifeng, Ge Yajie, Li Zhaoying
2013, 39(5): 569-573.
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An adaptive proportional navigation guidance law is proposed for hypersonic vehicle terminal guidance. The vehicle could be guided to impact the target precisely in a specific direction with required circular error probable. Based on the analysis of longitudinal flight, a convergence strategy was designed to make the proportional navigation guidance works earlier. The strategy allowed more time for the vehicle to meet the heading constraints at the impact. The precision of impact was affected by guidance parameters directly. However, vehicle would not conduct guidance commands ideally because of dynamic constraints. A close-loop nonlinear adaptive law was introduced to update guidance parameters online to improve the impact precision. Simulation results demonstrate the affectivity and accuracy of the proposed method.
Resonant gravity-assist trajectory design for Sun’s middle latitude exploration
Li Xiaoyu, Zheng Jianhua
2013, 39(5): 574-579.
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Sun's middle latitude exploration targets on the observation of the solar middle-latitude region from inclined orbits. In order to achieve this, resonant gravity-assists trajectory(RGA) was investigated considering the constraints of nearest distance to the Sun. After the deduction of analytical expression of out-going excess velocity, dimensional normalization was performed in order that the results can be applied to any gravity-assist planet with proper scaling. Then a novelty graphical method for gravity-assist analysis was proposed as RRpInc graph, which visualized the relations in resonance ratio, normalized perihelion and inclination. From RRpInc graph, the magnitude of excess velocity was concluded to be the key parameter for final inclination. Thus several other gravity-assists should be carried out before RGA and optimized by multi-objective genetic algorithm for both minimum escape energy and maximum excess velocity at the beginning of resonant gravity-assist planet. Then RRpInc graph was used to get the proper resonant ratio. Two trajectory options are listed up as promising choices. The first option takes a flyby sequence of venus-earth-earth(VEE) before Venus resonant gravity-assists to the final inclination of 30 . The second option uses Jupiter flyby to speed up, which is followed by Earth resonant gravity-assists to reach an solar ecliptic inclination of 35 .
Mathematical simulation method to calculate air minimum control speed
Jia Zhongren, Huang Chengtao, Wang Lixin
2013, 39(5): 580-584.
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The determination of the air minimum control speed VMC is an important content in the civil aircraft airworthiness compliance verification. The value of VMC is one of the vital bases to design the rudder and engine layout of an aircraft. Based on the physical understanding of the VMC airworthiness compliance flight test, a method to calculate VMC by mathematical simulation was proposed. According to the behavior characteristics of the pilot in the VMC flight test, the mathematical pilot model was established. Then, the pilot-aircraft closed loop flight simulation model for the VMC flight test was set up. Based on the accurate mathematical simulation of the VMC flight test, the value of VMC under different test conditions can be obtained. The method to calculate VMC proposed has important theoretical and practical value to guide the aircraft design and airworthiness compliance flight test.
Slipstream characters comparison of improved actuator disk model and 3D propeller numerical simulation
Duan Zhongzhe, Liu Peiqing, Qu Qiulin, Liu Zhenchen
2013, 39(5): 585-589.
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Four different propeller simulation models were compared to study the influence of propeller slipstream by solving Reynolds averaged Navier-Stokes(RANS) equations, including two prediction methods of the standard strip theory with and without rotate velocity correction applied in the actuator disk models and the uncorrected actuator disk model and 3D propeller model on a certain condition (at free stream velocity 66.889 m/s, with propeller rotation of 2 575 r/min and propeller radius 1.008 m). Results of axial and tangential velocity distribution behind the propeller show that propeller slipstream area could be predicted by the actuator disk model and the 3D propeller model when more flow details are reflected by the 3D model with more calculation cost. It all proved that the numerical simulation of 3D propeller could be replaced by the actuator disk model.
Simulation of re-entry capsule thermodynamics environment by DES method
Liu Jia, Yan Chao, Zhao Rui, Jiang Haijun
2013, 39(5): 590-594.
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Detached eddy simulation (DES) is an effective numerical simulation method for unsteady separated flow since it combines the advantages of both Reynolds averaged Navier-Stokes(RANS) and large eddy simulation (LES) methods. Spalart-Allmaras(SA) based DES method is used for the re-entry case under hypersonic condition. Comparison of the pressure and heat flux distributions shows that the numerical results agree well with the experiment data and thus validate the advantages of the DES method. Compressibility corrections were added in the original SA turbulent model. In the hypersonic flow characterization, the introduction of compressibility corrections can better the original turbulent method's simulation capability.
Computer analysis of large-scale aircraft landing gear retraction and extension control system
Tu Yi, Xiao Xiang, Li Nan
2013, 39(5): 595-599.
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A variety of constraints and influence factors need to be considered in landing gear retraction and extension (R/E) control system design. System simulation platform is an important auxiliary method for the system design. The hydraulic accessories simulation models of large-scale aircraft landing gear control system were established based on the fluid system simulation software Flowmaster, and the system simulation model was constructed using the established component models. Analysis of the landing gear retraction process for normal flight state was conducted based on the present system simulation model, and impacts of the actuator size on system entry pressure requirement, hydraulic fluid flowrate and the gear retraction time were also provided. The simulation method can be used for the preliminary design of the landing gear R/E control system and the verification of system design for different flight conditions.
Optimization of target designation for air-ship missile under condition of bearing-only attack
Sun Tao, Xie Xiaofang, Tang Jiang, Xue Wenguo
2013, 39(5): 600-604.
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Bearing-only attack is one of the most effective approach for air-ship missiles to adapt complex electromagnetic combat environment. Because of the absence of target distance information, the target designation and the fire control parameters are hard to be solved. Based on the analysis of quantization error of airborne sensors, the optimized estimation method of target parameters based on the measurement of target rotation speed by the airborne sensors was proposed. The error of the original and optimized estimation method was analyzed and compared. The distribution of locating precision in polar coordinates of the proposed method was simulated by the approaches of airborne passive radar and omnibearing warning system. The simulation shows that there are error divergence domains determined by the orientation of target and the quantization error of airborne sensors. Further more, the optimized maneuver strategy of battleplanes under the condition of bearing-only attack was proposed, which suggests that battleplanes be out of the divergence domains, and be away from these domains as far as possible.
Numerical simulation of parafoil aerodynamics and structural deformation based on loose coupled method
Zhang Chun, Cao Yihua
2013, 39(5): 605-609.
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The aerodynamic characteristic and structural deformation of two kinds of parafoils, one without cells and one with cells, were numerically simulated by utilizing loose coupled method to study the cell's effect on parafoil aerodynamic performance and structural deformation. In terms of fluid analysis, the finite volume method was used to solve Navier-Stokes equations and the shear-stress transport (SST) k-ω two-equation turbulence model was applied to simulate the turbulence. In terms of structure analysis, parafoils have initial shape was assumed and interpolation method was used to pass mapped pressure data in the interface. ANSYS was also used as a numerical solver. The final results show that cell has little effect on drag and its effect on lift occurs when angle of attack is high; parafoil's flexibility and size have little impact on the range of favorable angle of attack; the deformation and maximum principle stress are mainly concentrated in the middle of cells, the aerodynamic deformation of parafoil with cells is small because of the ribs and this ensures parafoil better aerodynamic characteristics to some extent.
Multi-routes dynamic planning on deck of carrier plane based on clustering PSO
Han Wei, Si Weichao, Ding Dachun, Song Yan
2013, 39(5): 610-614.
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To solve problem of multi-routes dynamic planning on deck about carrier plane, a method based on clustering particle swarm optimization (PSO) was proposed. The mathematic model of the problem was established. On the basis of establishing the whole environment modeling of aircraft carrier deck, the convex hull modeling of carrier plane and the collision detecting modeling, clustering PSO was used to solve the problem. In the end, the resolving method was realized by compiling program. Simulation show that the results meet the precision demands and the calculating efficiency also meets the practical demands. So using clustering PSO to resolve the problem of multi-routes dynamic planning on deck is feasible.
Assembly sequence planning for aircraft based on non-orthogonalinterference matrix
Sun Zhanlei, Zhao Gang, Han Pengfei, Guo Chunying
2013, 39(5): 615-620.
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Aircraft components assemblies contain many curved features in surface, complex relationships and multiple connects between parts, which make it difficult to design assembly process. A novel assembly sequence planning methodology based on non-orthogonal interference matrix was proposed. By analyzing the features of the part to be assembled, non-orthogonal assembly directs were extracted. The non-orthogonal interference matrixes were established. The method of deriving assembly feasibility was given to realize assembly sequence planning automatically. The sequences were optimized utilizing genetic algorithm, in which assembly time was used as the objective function. The assembly of the aircraft cabin door was simulated based on MATLAB platform. The simulation results indicate that the method implements simply. Assembling ability and efficiency are improved significantly compared to traditional method based on orthogonal interference matrix.
New approach for generating flight load spectrum of civil aircraft
Liu Xiaoming, Wan Shaojie, Xiong Junjiang, Li Qiang
2013, 39(5): 621-625.
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A novel approach was outlined to generate flight load spectrum for a new civil airplane from the statistical data of actural flight load on similar type of ones. The flight spectrum and continuous stress sequences of new civil airplane were derived from the statistical data of actural flight load of B737-400 plane by means of the analogism and the gust and maneuver spectra were then generated on the basis of the TWIST method. Finally, 5 5 ground-air-ground spectrum was obtained from the random sequencing. The example shows the practical application of new approach.
Full assembly fluid/structured flutter analysis of a transonic fan
Zheng Yun, Yang Hui
2013, 39(5): 626-630.
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Numeric method for blade flutter with coupled fluid'structured approach and aeroelastic model of full assembly fan blade vibration were developed. The coupling was achieved by solving governing equations for fluids and the blade vibration simultaneously and exchanging boundary condition at each time step. In the fluid domain, the unsteady Navier-Stokes equations are solved numerically to assess the effects of the deforming blades on the flowfield. The blade motion was calculated by integration of aerodynamic forces on the blades and solving structured dynamic equations. The blade flutter was conducted on a full assembly model in order to avoid pre-defined Inter-Blade-Phase-Angle. This method is capable performing aeroelastic stability analysis of multiple modes/nodal diameter in an unsteady computation, thus the efficiency of time domain aeroelasticity approach was improved. Detailed fluid/structured interaction analysis of NASA rotor 67 were conducted at choked, peak efficiency and near stall operation points to assess the effect of nodal diameter on the aeroelastic stability, the least stable blade vibration mode and nodal diameter was presented. The result indicates that nodal diameter of blade-row vibration is the most influential factor to the aeroelasticity.
Numerical simulation of separated turbulent flow using GAO-YONG turbulent model
Gao Lin, Gao Ge, Jiang Lijun
2013, 39(5): 631-634,639.
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Numerical simulation of separated flow around a triangular cylinder and turbulent flow over a rearward-facing step in a diverging channel flow using GAO-YONG turbulence model were presented. All calculations were based on open field operation and manipulation(OpenFOAM), which is a open-source computational fluid dynamics(CFD) platform. The calculations predict the vortex shedding of flowing around bluff body and reattachment of flowing over rearward-facing step in a channel accurately. The distribution of pressure coefficient, friction coefficient and velocity were simulated numerically with GAO-YONG model, and agreed well with the experimental data. The results demonstrate that GAO-YONG turbulence model was capable to simulated the turbulent flow with large separation, and be of basic instructional effect to engineering and practice.
Adaptive subspace band selection method based on spectrum characteristics
Xu Qiu, Li Na, Zhao Huijie, Li Xudong
2013, 39(5): 635-639.
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Adaptive subspace band selection method based on spectrum characteristics was proposed to solve the problems, including the existing methods which couldn't divide subspace by studied features and background features easily affected the result of subspace division.Spectral adaptive factor (SAF) was established with the spectral curves of studied features, and the whole data space was divided into some subspace based on clustering. In each subspace, Jeffreys-Matusita distance was calculated to choose the maximum class separability band as the optimal band. The optimal bands combination was achieved.With the data of acousto-optic tunable filter (AOTF) imaging spectrometer,an experiment was accomplished to compare with other band selection methods, involving band index (BI) method and the optimal bands selection method based on the classes distinguish ability. Experimental results show that the optimal bands combination of the proposed method contains better performance and studied features are shown more significant difference. And the average of Jeffreys-Matusitadistance of all classes of the proposed method is the greatest of all methods.Maximum likelihood classification method was also implemented on the images of the optimal bands combination of the proposed method. As a result, the overall accuracy is 96.8% and Kappa coefficient is 0.89.The experiment indicates that the proposed method is effectiveness and practicability.
Dynamic modeling for a climbing robot
Yue Ronggang, Wang Shaoping
2013, 39(5): 640-644.
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City-Climber robot is a novel wall-climbing robot which has the capability to move on floors, climb walls, walk on ceilings, and transit between them. In order to research 3D path planning problem, kinematic modeling and dynamic modeling for the City-Climber robot in a cuboid room were built. The dynamics model includes three sub-models which can describe that City-Climber moves on floors, walls and ceilings respectively. Non-dimensional variables were introduced to simplify the models. The correctness of the model was verified by simulation results given by Matlab software since the trajectories match the expected practical motion of the robot. The models are suitable for solving path planning and obstacle avoidance problems in 3D building environments.
Attitude estimation based on quaternion square-root cubature Kalman filter
Qian Huaming, Huang Wei, Ge Lei, Zhang Guangtuo
2013, 39(5): 645-649.
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Considering that a multiplicative extended Kalman filter (MEKF) existed lower estimation accuracy and slower convergence rate for large initialization errors, a quaternion square-root cubature Kalman filter (QSCKF) was proposed. A quaternion nonlinear error model was derived for attitude determination system, and then the cubature numerical integration theory was used to calculate the mean and variance of the nonlinear function. The square-root forms were used to improve numerical stability. To avoid the quaternion normalization problem, a Lagrange loss function was derived to compute the average quaternion. The simulation results indicate that the proposed algorithm provides higher estimation precision with faster convergence rate and better filter's stability than MEKF and unscented quaternion estimator (USQUE) for large initialization errors. And, the estimated time of this algorithm is shortened by 1/3 compared to USQUE.
Time and cost performance evaluation algorithm of workflow model
Pan Jun, Liu Li
2013, 39(5): 650-654.
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The time and cost performance parameters of acyclic workflow model were analyzed, the introduction of the extraction algorithm of the circular structure made it possible to evaluate the time and cost performance of ring workflow model. Using improved Tarjan algorithm and 7-tuple, each cycle structure parameter was extracted and stored. All 7-tuples were analysised, the time and cost values of all sign nodes of workflow model were calculated. The model will be converted into acyclic structure after the loop structures were extracted. It can evaluate the time and cost performance by using acyclic workflow model algorithm. Experiments show that the algorithm can be very effective to calculate the time and cost performance of the complex model.The algorithm is efficient and the results are accurate.
Approximation by normal distribution with covering width based EM estimation
Han Liyan, Cai Mingsheng, Yin Libo
2013, 39(5): 655-659.
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Based on the comparison and analysis on existingnon-normal distributions, the approximation method by using mixture normal distributions was proposed. For overcoming the order determination difficultyin maximum likelihood estimation based expectation maximization (EM) algorithm, the maximalcovering width principle (MCWP) for order determining was designed. The experiment result supports the feasibility of the method. It shows that the fitting by MCWP has the advantage of the Akaike information criterion. In calculating the covering width, it is necessary to adjust the maximum mean and the minimum mean by the standard deviationbased weights.
Error analysis of surface current density on perfect electric conductor based on physical optics
Ji Jinzu, Ma Yunpeng, Huang Peilin, Zhang Zhongjian
2013, 39(5): 660-664.
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In radar cross section (RCS) calculation of perfect electric conductor (PEC) targets using physical optics (PO), the surface current was calculated based on the assumption of infinite tangent plane. The assumption was fulfilled only for the electric-big and smooth-surface targets, while there is error induced by PO in general situation. The PO's surface current of two-dimensional profiles such as cylinder, square prism and triangular prism was calculated and compared with accurate or method of moments (MoM) result. The analysis shows that when transverse magnetic (TM) wave is incident on the target, PO reflects the true situation except for some vertices. However, when transverse electric (TE) wave is incident on the target, PO cannot show the resonant oscillation in illuminated and shadowed surfaces and there are still big errors in the surface current parallel to the incident direction.
Ray path tracing on discrete surface
Chen Zhixian, Su Donglin, Liu Yan, Fang Xiang
2013, 39(5): 665-669.
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In order to analyze antenna isolation on discrete surface, a new algorithm for ray tracing that called "minimum included angle algorithm" was proposed. First, the discrete surface was divided into triangular mesh to generate surface grid data that accord with the format required in the article. The data mentioned above was processed by using minimum included angle algorithm that was proposed in this paper. Then the length of geodesic path between any two points on discrete surface could be quickly and veraciously achieved. The length of geodesic path between any two points on cylinder, ellipse and discrete arrangement was computed, to confirm the veracity of "minimum included angle algorithm" on discrete surface.
Brittle behavior of gold alloy joint soldered with tin-lead solder
Yin Na, Qu Wenqing, Yang Shujuan, Li Rui
2013, 39(5): 670-673.
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Soldering of Au60AgCu using tin-lead solder was performed in the experiment. The soldering joint of microstructure, micro-hardness, phase composition, mechanical properties and fracture morphology were analyzed, and the effect of interface intermetallic compound on joint brittleness was discussed. It was found that the compound of Au60AgCu alloy soldering joint was composed of AuSn2, Ag3Sn and AuSn4. With increasing the soldering temperature and/or time, the thickness of intermetallic compound was obviously increased. The hardness of intermetallic compound was high. The soldering joint of shear mechanical property test indicates that fracture occurred in the intermetallic compound layer, and the fracture morphology is brittle fracture.
Fatigue property of Al-Li alloy friction stir welded lap joints
Zhang D, an, Qu Wenqing, Yang Mocong
2013, 39(5): 674-678.
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Through the fatigue test, fracture characteristic and microstructure analyses, the fatigue property of the Al-Li alloy friction stir welded lap joints and the effect of "hooking defect" appearing at the thermal-mechanically affected zone(TMAZ) of advancing side on the joint fatigue property were studied. The results show that the cracks can easily initiate and extend from the location of hooking defect, leading to the decrease in the "effective sheet thickness"(EST) of material and damage to the joint fatigue behavior. The appropriate reduction of the pin length is proved one way of to improve the defects and mechanical property of joints. Furthermore, the established S-N curves show that the fatigue life of lap joints is close to base metal on the high fatigue stress. As the fatigue stress decreasing, the joint fatigue life sharply declines and the fatigue strength of joints at fatigue life N=2 106 is only 80 MPa, only equivalent to 35% that of base metal.
Solution algorithm of the three-body lambert problem with gravity assist maneuver
Luo Qinqin, Han Chao
2013, 39(5): 679-682,687.
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A new numerical solution algorithm for the three-body Lambert problem with gravity assist maneuver was developed. The algorithm was divided into two parts, the initial solution design and the searching for the final solution. The pseudostate theory was adopted to get the initial solution of the three-body Lambert problem. Based on that, the transfer trajectory and the state transition matrix were calculated by numerical integration in the real dynamic model. A second order differential-correction method was employed to find the final solution. The numerical examples were used to test the reliability and the efficiency of the algorithm.
Total dose dependence of off currents in the irradiated PD-SOI devices
En Yunfei, Liu Yuan, He Yujuan
2013, 39(5): 683-687.
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Total dose dependence of off currents in the partially depleted SOI devices with standard and enclosed gate structures was presented. The experimental results show that increases in the radiation induced off current are result from the effect of trench sidewall leakage, the conduction of back gate parasitic transistor and the coupling effect of band-to-band tunneling and back gate leakage currents. In the standard structures, trench sidewall leakages are increased by the positive charge trapping in the field oxide, thus the off currents in the front and back gate is increased significantly. In the enclosed gate structures, increases in the off current are more caused by the conduction of back gate parasitic transistors and the drain current dependence on total dose at negative gate-source voltage are caused by the coupling effects of band-to-band tunneling and back gate leakage currents. These results can be used for hardness assurance by improving of device layout structures.
Ultrasonic phased array inspection for the corner of composite components
Zhang Dongmei, Yu Guang, Zhou Zhenggan, Xu Na
2013, 39(5): 688-692.
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Ultrasonic phased array inspection for the corner of composite components was researched on experiment. The difficulties of the corner inspection and advantages of ultrasonic phased array inspection technique were dealt with. Then two kinds of inspection methods with curved array transducer and linear array transducer were put forward. The experiments of the corner inspection of L-shaped composite component were conducted with the two methods, which verified the correctness of the two kinds of methods. Finally, the two inspection methods and conventional ultrasonic inspection method were contrasted and the advantages of the corner inspection using ultrasonic phased array technique were summarized. The results show that ultrasonic phased array technique is a feasible, efficient detection method, which can satisfy the inspection requirement of the corner of composite components.
Post-processing of volumetric PIV data based on continuity condition
Gao Qi, Wang Chengyue, Wang Hongping, Wang Jinjun
2013, 39(5): 693-696.
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A new technique of data post-processing was proposed to improve volumetric velocity field of particle image velocimetry (PIV).To make the processed velocity field satisfy the differential form of the continuity equation of incompressible flow, the modification was made on the original experimental data. The correcting velocity field was obtained by solving the minimum problem of its 2-norm using the method of Lagrange multipliers. Mathematical proof was provided to demonstrate that the modified velocity field was a better approximation of the true flow. Simulation of an analytical flow with noise was performed to further prove that the post-processing technique can reduce the common Gaussian noise of PIV measurements. The technique is successfully applied to a volumetric PIV data, which indicates that it can improve the smoothness of the velocity field as well.
Prediction of electromagnetic interference based on neural network
Yang Tianpeng, Ma Qishuang, Xie Qingming
2013, 39(5): 697-700,705.
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A method to predict the electromagnetic interference using neural network was proposed. Genetic algorithm has the strong overall search ability but easy to fall into local optimum, and simulated annealing algorithm has the partial search ability, avoiding the search into local optimal solution. By using the simulated annealing algorithm and genetic algorithm combining, the back propagation (BP) neural network weights and thresholds were optimized, and the number of hidden layer neurons was determined by the simulated annealing ideas. Then, the neural network-based predictive models of electromagnetic interference was established. With the two parallel leads to electromagnetic interference matter as predicted instance, interference factors were identified, and the training and test samples were established. In contrast to the error between the expected output and the predicted output, the results show that the method can accurately predict the electromagnetic interference effectively.
Storage reliability analysis of missile based on multi-mechanism competition degradation method
Luo Xiangyong, Huang Xiaokai
2013, 39(5): 701-705.
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Remote switch, radio altimeter, radar angle automatic device, gyroscope and power equipment are the main influence equipments for long-term storage reliability of missile. Firstly, the storage profile of missile was defined, and feature voltage value of influence equipments were obtained from regular tests in the long-term storage condition. Secondly, the storage stability levels of the feature voltage value were considered by the moving standard deviation method, and the storage lives of all main influence equipments were obtained from fitting for storage stability levels. Thirdly, storage lives of main influence equipments of 10 missiles were obtained, and the distributions and their parameters were identified. Finally, the multi-mechanism competition results of missile storage reliability were obtained by the multi-mechanism competition degradation method according to different consideration of missile storage lives. The thought method and conclusions of the paper have significant meaning for the improving of missile storage reliability prediction and design.
Parallel acquisition algorithm in time-frequency domain
Zhan Wei, Zhang Xiaolin, Li Juan
2013, 39(5): 706-710.
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Due to the fact that the classic method of parallel acquisition in the time or frequency domain cannot satisfy the demand of the fast acquisition of the direct sequence/frequency hopping(DS/FH) hybrid spread spectrum signal in TT&C. In order to further improve the acquisition accuracy of the carrier, on the basis of the partial match filter-fast fourier transform(PMF-FFT) algorithm, a parallel algorithm in the time-frequency domain with feedback architecture was proposed. Through the coarse estimation of the carrier frequency offset by the PMF-FFT algorithm, the new algorithm uses the Quinn frequency interpolation algorithm to improve the estimation accuracy of frequency offset, modifying the local carrier by employing the estimated result and reacquiring. Theoretical analysis and simulation results show that, compared to the PMF-FFT algorithm, the new method improves acquisition accuracy of the carrier, under the conditions of large frequency offset and low SNR, increases the frequency analysis bandwidth, and reduces the average acquisition time.

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