Abstract:In order to study the bearing capacity of the aluminum honeycomb sandwich panel, outdoor test road was built, rigid bearing plate with 30 centimeter in diameter was used to simulate the tire load of aircraft. Displacement sensors and strain gauges were placed on the surface of the sandwich panel, vertical deformation and surface strain were measured with the foundation of different resilient and unevenness. Experiment results show that the rise of foundation modulus can improve the stress condition, reduce the vertical deformation. The void can produce large deformation on the bottom of the panel, reduce its bearing capacity.

Abstract:In view of the application of jet piston ejection mechanism in vertical ejection system, the source item method and user defined function (UDF) technique of CFD fluent software are used to inject mass, momentum and energy of propellant gas into high pressure chamber, the jet flow field in the high pressure chamber and the low pressure chamber at the initial stage is analyzed numerically, the pressure and the velocity distribution and changes are obtained, and the influence on the ejection mechanism from the pressure and the velocity is analyzed. The computation results show that this method can well simulate the ejection mechanism characteristics of the inner flow field, and can provide a theoretical basis for ejection mechanism and propellant design.

Abstract:Firing of the OTS missile is conditional, and only by ensuring safety can a fighter use the OTS missile to attack the rear target. Therefore, while attacking the rear target the pilot of the fighter should also consider the target's threats to the fighter. Firstly, this paper analyzes several factors those threaten to fighter's safety by a threat-factor method to determine the proportion of each factor, and provides evidences for the pilot to make correct choices. The paper also briefly describes the path tangent avoidance method and illustrates the situations for adopting the method. And then the paper presents a launching opportunity of over the shoulder missile. The basic principle is to ensure that the fighter is beyond the target's threat while the target still can be hit by the OTS missile. The simulation results show that it is necessary for a pilot to make decisions under the enemy's threat, and simultaneously commanding the opportunity of launching over-the-shoulder missile is of great importance to winning the air combat.

Abstract:In order to alleviate the problem of flight delay is increasingly prominent, especially in the terminal control area.the process of sequencing of arrival aircraft in the terminal control area is divided into two phases, i.e. route phase and gathering sorting phase. The problem of sequencing of arrival aircraft in the terminal control area is studied by adopting a single machine scheduling algorithm combined with cell transmission theoretical algorithm. A cell transmission model of taking the shortest system running time as the target function is established by utilizing standard radar traffic circuit combined with the experience of the practice. The aircraft waiting for landing are segmented into different groups and are given the corresponding weights by using the integration principle of linked aircraft. According to the different effect of linked aircraft a reasonable order is given. The analysis result shows that the optimization model can reflect the dynamic characteristics of the arrival aircraft. This can give a reasonable landing sequence and can provide a reference for the path selection of the arrival aircraft in the terminal control area to meet the needs of actual operation.

Abstract:In order to overcome some inherent defects of Support Vector Machine(SVM), such as poor sparsity, heavy computation and kernel function satisfactory to the Mercer's conditions in the engine oil wear particle detection and the fault diagnosis, a new attempt by adopting a predictable method based on Relevance Vector Machine (RVM) is proposed. On the basis of the introduction of principle and deduction, the spectrum analysis data of a certain aero engine lubricating oil are utilized to predict the relationships between the aero engine oil wear particle concentration and fault. Through analysis and verification, the results show that the method based on RVM has more advantages in generalization over the SVMs and the ANNs under the same conditions, and the method can be widely used in the engine oil wear particle analysis and the failure prediction.

Abstract:The existing methods to evaluate the airport noise are mainly designed for fixed wing aircraft. In view of the different characters of military helicopter noise, these methods have some shortages and the noise evaluation index can not reflect the whole influence of military helicopter noise on the environment. In order to solve this problem, the characteristics of the military helicopter noise are discussed and the existing index is analyzed. And then a method of multi-index evaluation to evaluate the military helicopter airport noise is proposed by using LAmax and LWCEPN at the same time. This multi-index evaluation method can reflect both total noise level and single burst noise at the same time. The test result shows that this method can reflect the real feeling of the neighbor residents about the noise, which verifies that this multi-index evaluation method is more effective.

Abstract:In order to study the relationships between the resistivity and the salinity of chloride saline soil and of sulphate saline soil with different salinity under the condition of saturation state, the resistivities of chloride saline soil and sulphate saline soil with different salinity are tested. Through data fitting, a fitting formula of the resistivities of chloride saline and sulphate saline and the variation of salinity are obtained under the condition of saturated state. Compared with their resistivities the results show that the resistivity of chloride saline soil is bigger than that of sulphate saline soil under the condition of saturation state with the same salinity and output voltage, so is the rate of current change. This study is a salutary lesson for the research on electro-osmosis method for saline soil treatment.

Abstract:Under jamming conditions, calculation of number of firing times about ground-to-air missiles firing at air-raid formations, which enter the launch area with different ways, is a puzzle that the antiaircraft forces should urgently desolve, but are lack of system research. To solve this puzzle, the models of missile actual launch distance and number of firing times at air-raid formation in jamming condition are established by an analytical method, then the calculation methods of residence time of the air-raid formation entering the launch area with rule flow and poisson flow respectively are also given. Finally, the feasibility and effectiveness of the models are illustated with a numerical example and some practical and valuable conclusions are reached, which can provide a reference for the shooting efficiency evaluation, the firing training and the amelioration of weapon system.

Abstract:Extraction method of three-dimensional micro-motion feature from sliding-type scattering center in ballistic target is studied. Firstly, the characteristics of sliding-type scattering center are analyzed in the paper, a new feature extraction method based on half period delay multiplication is introduced, and the mathematical relationships between sliding-type scattering center and ideal scattering center are built up. And then parameters are extracted from echo signals by utilizing the multi-view characteristics of netted radar. Through the structure of nonlinear multivariable equation systems, the three-dimensional micro-motion paracters and part of the structure features are solved by taking an extracted parameter as variate. The simulation results show that the proposed algorithm is effective.

Abstract:In order to recognise the ballistic target by effectively utilizing the scattering centers of the target, a dechirping method is proposed. First, by proceeding planar FFT, the imaging for target's scattering center is achieved, and then target's feature information is extracted from its ISAR imaging. Finally, a new matching recognition method is proposed to realize target's classification. The method is used for judging target's classification by extracting the information from the scattering centers' position and amplitude through constructing matching matrixs and again comparing with the preinstall threshold. The simulations and the assessments of classified performance show that the method is efficient in target's recognition under the set conditions.

Abstract:In order to get better time-frequency analysis results of Micro-Doppler precession signals, this paper tries to analyze precession signals in the aspect of time-frequency through a Gabor-PWVD joint time-frequency analysis. Firstly, the method is used to get two arrays through performing Gabor transform and PWVD transform in precession signals, and make them do point multiplication. When signal items remain in both of them, the point multiplication result can be obtained. If the Gabor transform area in correspondance with the PWVD cross terms area has no value, the result of the point multiplication is zero. The simulation results show that the use of Gabor-PWVD joint time-frequency analysis method can get better time-frequency distribution without containing cross terms and have a good time-frequency clustering at the same time. Compared with the theoretical values, the periodic feature extracted by Hough transform to the Gabor and Gabor-PWVD time-frequency chart shows that the error decreases from 2% to 1.8%,and this verifies that the Gabor-PWVD is superior in performance.

Abstract:The micro-Doppler effect of rotating target is studied in bistatic frequency modulation continuous wave (FMCW) wideband radar in this paper. Firstly, the model of rotating target is established in bistatic FMCW wideband radar, and the expression of micro-Doppler effect is derived. Then, the conclusion is deduced from the previous that the primary error term causes one-dimensional range profile walk and peak deviation, and the quadratic error term causes the one-dimensional range profile widening, also the maximum of frequency deviation in micro-Doppler feature curve is modulated by the bistatic angle according to the analysis of the influence caused by micro-motion during the pulse repetition interval (PRI) on one-dimensional range profile . Finally, the error factor compensation approach based on minimum entropy principle is proposed. The simulation analysis indicates that the use of the method can estimate the coefficient of the quadratic error term in precision and can compensate the error factor of the micro-Doppler effect effectively and is good in anti-noise performance.

Abstract:To solve the problem of clutter suppression faced by airborned MIMO radar,after considering the element error,channel uncertainty as well as clutter fluctuation, , the clutter model for airborne MIMO radar under different error conditions is established,a new space-time adaptive processing method based on MIMO systems——M3-CAP method is proposed. Firstly,temporal filtering is performed on the space-time received data,and then the output data of three Doppler channels which are the detected Doppler channel and two of its adjacent channels,is adaptively filtered .By combining MIMO systems and 3-CAP method effectively,the advantage of waveform diversity is extended into 3-CAP method,this new method improves the degree of freedom and clutter estimation accuracy. By analyzing and comparing the clutter suppression performance under different radar systems and different error conditions,the result turns out:the clutter suppression performance of M3-CAP method is superior to JDL-GMB、Modified JDL、3-CAP methods.

Abstract:In this paper, a novel miniaturized Zeroth order Resonance(ZOR) patch antenna with broad beam width is presented. By inserting a centre-symmetric zeroth order resonance structure around circular micro-strip patch antenna combined the TM01 mode and ZOR mode induced by the circular patch and mushroom patch respectively, miniaturization and broadened beam width are realized simultaneously. The half power beam width of E plane and H plane are 114.7°and 144.7° respectively, compared with the original micros-trip antenna, the E plane and H plane HPBW of the new antenna is greatly broadened by 66.5% and 60.1%. Meanwhile, the resonant frequency is shifted from 14.04 GHz to 7.32 GHz, and the electric size is reduced from 1.9λ×1.9λ×0.1λ to 0.9λ×0.9λ×0.01λ to realize 52.1% miniaturization.Finally, the measurements show good agreement with the simulated one, which validates the correctness of the design.

Abstract:A triple-band printed micro-strip antenna fed by coplanar waveguide (CPW) is designed based on notched structure. The character of multi-band is achieved by adding slots to the radiation patch and micro-strip of planar monopole antenna. The antenna model is simulated and optimized by electromagnetism simulation software HFSS12 and a prototype is manufactured according to the result of simulation. The result of measurement fits well with that of simulation. The antenna can work on the bands of 1.85~2.53 GHZ， 3.14~4.38 GHz and 4.87~5.93 GHz (S11＜-10 dB)，which cover the bands of Bluetooth (2.4~2.48 GHz)， WiMAX (3.4~3.6 GHz) and WLAN (5.15~5.825 GHz). The antenna’s impendence and gain are good enough to meet the requirement of wireless communication in its working bands.

Abstract:In view of the problem that the security of network management is easily decreased by the center node troubles in the traditional satellite network management mechanism based on hierarchical-clustering structure, a novel scheme is proposed to meet the needs of the security cluster head, which supports the fast switching between formal and backup cluster head, and then a relevant new priority-based selecting algorithm is proposed for the formal and backup head selecting the formal cluster head and the backup cluster head through cluster members negotiating and priority calculating in consideration of communication ingredients comprehensively in satellite cluster such as accessibility, delay and reliability. The results of simulation indicate that the scheme can not only replace the failure cluster head and recover the cluster in very short time, but also minimize management cost of the cluster head.

Abstract:Long wavelength, weak ionospheric delay and low noise linear combination observational value can realize a quick determination of the integral ambiguity, and all the combined wavelength, the ionospheric delay coefficient and observational noise are determined by the combination coefficients. On the basis of the frequency factor, the ionospheric delay factor and the observational noise factor characterized by the combined wavelength, the ionospheric delay coefficient and the observational noise, the BDS/GPS B1、B2、L1、L2 four-frequency combination observation coefficients suitable for integral ambiguity resolution are obtained. The functional relationships of the combination observation coefficients, the frequency factor and the ionospheric delay factor are obtained under the condition that the observation noise is in the lowest by utilizing the function method. The results show that the combination observational values determined by the three groups, i.e. , and are comparatively long in the combination wavelength, comparatively weak in the ionospheric delay error and comparatively low in the observation noise, which are suitable for integral ambiguity resolution.

Abstract:In the application of airbone single-observer passive wireless radio frequency injection location, if there has outliers in the observed value, the application of the EKF algorithm will make the location estimation biased. Therefore, a robust EKF algorithm is applied to airborne single-observer passive wireless radio frequency injection location system. Firstly, airbone single-observer passive bearing location model is build, and the robust equivalent weight matrix built by standardized observation residuals is used to resist outliers. Then, in order to improve the efficiency of passive location system, the robust EKF based on chi-square test is proposed by creating a chi-square statistical model. It can distinguish outliers through chi-square test, and then call the robust EKF to complete location solution. Through rejecting single outlier and continuing outliers to test the ability of the algorithm. Simulation result shows that the suggested algorithm has great outlier suppression ability and the robust EKF based on chi-square test is fast.

Abstract:The time synchronization accuracy on the order of nanoseconds can be provided using the conventional methods of time synchronization, a higher measurement accuracy on the order of femto-seconds can be reached by quantum measurement which employs entangled photon pairs in order to break the limit of measurement accuracy of conventional methods. The second-order correlation function of the entangled photon pairs which produced in a spontaneous type-Ⅱ parametric down-conversion is investigated by integral transforming in the nonlinear crystal and substituting the first order expand of the wave vector. The relation between the second-order correlation function and temporal difference. A quantum method in clock synchronization between satellite and ground station is proposed based on the temporal correlation. The simulation indicates that the measurement accuracy provided by the second-order correlation function can be 70 femto-seconds and the synchronization accuracy in the scheme can be 140 femto-seconds in the ideal case.

Abstract:Aimed at the problem that the security of some multi-secret sharing schemes only depends on a single coefficient, and based on the bilinear pairings and the Shamir threshold scheme, this paper proposes a public verifiable secret scheme. In the scheme, the secret key computation of participant is apart from the process of secret distribution. The secret key is chosen by the participant himself and the participant only needs to keep one secret key. By so doing the multi- secrets sharing at will in the process can be realized. The public verifiable scheme is effectively applied in the process of the secret distribution and the secret recovery ,so that anyone could be able to verify the correctness of the share to effectively prevent the dishonest participant and the dealer from cheating. The dealer and the participant transmit information through the public channel rather than the secret channel, thus reducing the system costs. The sharing of multi-secret lies in multiple coefficients, and the leak of a single coefficient or secret does not lead to the leak of other secrets. By using the Elliptic Curve Discrete Logarithm Problem and Bilinear Diffie-Hellman Problem, the security of the scheme is guaranteed. At last, mathematical proof and theoretical analysis of validity and expansion of the scheme are given.

Abstract:Parameters identification and complete synchronization between the fractional-order chaotic liu system and the factional-order chaotic system with uncertain parameters are investigated in this paper. Firstly, based on the stability theory a synchronistic controller containing a time-varied gain and an estimating variation is proposed, and the estimating variation is a kind of approaching continually to the true value of the uncertain parameters with time evolution. Secondly, the method of synchronization is proved. Finally, some examples are given for simulation and verification. The simulation results show that the parameters identification and the complete synchronization are realized simultaneously by using this method. Furthermore, the equations are identical and only the parameters are different in the three examples, and the switching synchronization can be realized between liu system and three different chaotic systems by altering partial parameters.

Abstract:In order to solve the standardization problem of test information existed in integrated support technology, standardized requirements of integrated support technology are analyzed. Based on ATML standard, Using UUT description as an example to explain the standardized modeling and description method of test information, and the XML Schema model is built in hierarchical way. Combining with a certain type of integrated support equipment for concrete description, on the basis of the standardized modeling and description method of test information based on ATML, the standardized model of test information of support equipment UUT is built, and using the diesel generator to illustrate concretely, the standardization modeling and description based on ATML can realize the unity of the format of test information, reduce reliance on special tools or code, reduce testing information parsing and processing difficulty, and effectively solve the standardization problem of test information in the integrated support technology.