Abstract:A basic current statistical model can only be applied to maneuvering target with high acceleration because its upper and lower limits of target acceleration is fixed and invariable. So a basic current statistical model and an adaptive filter algorithm has a good performance on maneuvering target with high acceleration but a poor performance on maneuvering target with low acceleration. In order to solve this problem, a novel fuzzy membership function is presented which uses the current acceleration of maneuvering target to adjust the upper and lower limits of target acceleration adaptively. This new algorithm makes sure that the current statistical model can be applied to maneuvering target with any acceleration. Finally, track prediction simulation is did which uses this new algorithm and CSAF algorithm to predict the track of maneuvering target. Simulation results show that, the prediction performance of this new algorithm is much better than CSAF algorithm on maneuvering targets both with low and high acceleration.

Abstract:Aimed at the problem of the previous fault-tolerant system and that the ordinary least squares support vector machine (LS-SVM) can not effectively perform local detection when a trouble appears in the inertial navigation system of aircraft, a fault detection method based on local weighted LS-SVM is proposed.Firstly, the LS-SVM is locally weighted. Then the innovation of filter by the forecasted innovation of the local weighted LS-SVM regression is used for the test statistics. At last,based on the ADS/GNSS system platform, a simulation is done and analyzed. The result shows that the local weighted LS-SVM fault detection algorithm is good in detection effect, and by using this algorithm the fault detection time and fault isolation rate are reduced greatly.

Abstract:In this paper, a closed plasma generator is designed. The discharge experiments are carried out in the closed cavity under low pressure environment by adopting the method of inductively coupled plasma(ICP) and taking argon as a working gas. The distribution rules of the electron excitation temperature, electron density, and the effect of RF power on the electron excitation temperature and electron density are investigated by means of emission spectrum. The changes in the electron excitation temperature are analyzed by using the method of the Boltzmann plot, and the variations in the electron density are derived from the analysis of Ar 750.38 nm line intensity. A uniform plasma sheet is produced stably by the closed plasma generator, in which the electron excitation temperature is about 9 500 K. The electron density and electro excitation temperature can be enhanced by improving RF power. With adequate input power, the variations of parameters of the closed plasma at different positions change little.

Abstract:In this paper, aircraft equivalent single wheel load coefficientζ and adjacent wheel effect coefficient φ of airport flexible pavement structures are introduced, and the concepts and formula expressions of equivalent single wheel load are defined. Calculation methods of φ and ζ are introduced. Based on flexural tensile stress, strain at the bottom of structure layer and compressive strain on top of sub-grade, the rule of ζ with pavement structure parameters is analyzed when the main landing gear configuration of aircraft is dual wheel, dual tandem wheel or three axis wheel respectively. The paper suggests that in calculating ζ of flexural tensile strain at the bottom of asphalt layer and of flexural tensile stress at the bottom of rigid or semi-rigid base, the only one axle (or a row) load should be considered, and in calculating compressive strain on top of sub-grade, all adjacent wheels should be considered. At last, the approximate formulas of equivalent single wheel load coefficient for more than 40 kinds of aircraft based on flexural tensile stress, strain at the bottom of structure layer and compressive strain on top of sub-grade are given.

Abstract:It’s an important aspect of researching reliability and invulnerability of networks to evaluate the node importance. In consideration of the disadvantages of other current methods, this paper presents a method for finding the vital node in weighted networks by using the node importance contribution matrix, in which the position of node and the contribution of other adjacent nodes are taken into account and a node’s importance value is initialized as its node efficiency and different nodes contribute importance value dissimilarly to a certain node according to its point weight. It can update the evaluation matrix when weighted value changes. Finally, the algorithm is compared with both betweenness method and node contraction method, and final experiments verify the efficiency of the proposed method.

Abstract:A model of air and missile defense system network is built up by adopting HK complex network model, and its degee distribution, clustering coefficient and average path length are studied. Compared the statistical characteristics of this model with those of the typical air and missile defense system network based on small-world networks, the result shows that the air and missile defense operational network based on HK complex network model has a good clustering coefficient and scale-free property. And simultaneously the model has more TF probability, and can also provide more advantages for the personnel in special field to design the air and missile defense system network

Abstract:Based on the force analysis of missile in missile lording training, the missile force model and position and pose transformation math model are both built. Using Visual C++ as the programming language and OSG as the graphics engine, the position and pose real-time control method for missile is designed, which can interactively control the missile's position and pose in virtual scene efficiently and briefly. Results indicated that this method can made visual simulation of missile lording training more realistic. This study laid the foundation of building the virtual loading distributed co-training system.

Abstract:A coordination trajectory planning method of multiple unmanned air vehicles (UAV) based on hierarchy strategy is researched, the research is divided in three hierarchies, i.e. route planning, coordination control and trajectory control. Multiple routes for each UAV are given based on K-means clustering algorithm and genetic algorithm. A new method is proposed to solve the problem that the use of the traditional algorithm could not find out the result of coordination variable. According to the six degree of freedom model and the coordination variable, a fixed terminal time optimal trajectory control model is built up for each UAV, thus the optimal control problem is converted to NLP problem with the LPM, and the model is solved by using CFSQP method, and then the plan of control parameters and attitude is realized. The simulation shows that the coordination trajectory of UAV obtained by this method is better in operability, less in computational complexity and higher in computational efficiency, and simultaneously the control command obtained is smooth and easy to operate.

Abstract:Aiming at the path planning of URAV, the GIQE (general imagery quality equation) was introduced to forecast image quality of targets. An evaluation function comprehensively considering the image quality of targets, the length of reconnaissance route and threatening factors was designed as a fitness function for particle swarm. The Pareto set can be gained through particle swarm algorithm, thus the optimal solution will be determined by weighting objectives. The simulation results showed that the UAV reconnaissance path planning considering the factor of image quality can better meet the demands of imaging reconnaissance missions.

Abstract:According to the fact that TACAN system has low duty ratio via analysis of its function and signal, this paper proposes a new task of expanding digital communication function without influencing the existing navigation function and the signal format of the TACAN system. The main limiting factors and technical problems which must be solved are analyzed. This paper discusses the possible technological approaches and points out the direction of concreteness study.

Abstract:A decision directed acyclic graph support vector machine is a typical multi-class classification with support vector machines. But error accumulation exists in the traditional decision classification, and its generalization ability depends on the tree structure. In this paper, to improve the generalization ability of DDAGSVM, a novel separable measure is defined based on the generalized KKT, and an improved decision directed acyclic graph support vector machine is given. The three-spiral and HRRP experimental results show that this kind of algorithm has an obvious effectiveness in controlling classification errors.

Abstract:By analyzing the structure of boundary layer, the boundary layer outside the plane bulkhead is viewed as negative lens. The focusing effect of light beam transmission in the airborne laser communication is simulated under the high-speed maneuvering and upper atmosphere conditions. The result shows that there is a direct proportion function between the flight Mach number and the focusing effect under a constant flight altitude. At sea level, for Mach number 2 or more high-speed maneuvering platform, the -FIRs is lowered to less than 8. At the altitudes of 10km and 15km, the ratios can respectively reach to16 and 25. When the ratio comes up to more than 6.3, the BER can be satisfied.

Abstract:A cross-channel problem will appear when a wide-band signal passes the channelized receiver with multi-channel output. It's very meaningful to solve the cross-channel problem quickly and efficiently. This paper analyzes the time-association relationship between the output signals in adjacent channel, and then a criterion of whether the outputs came from the same radiant point is proposed, meanwhile a reliable method of estimating signal's parameters is presented, which can be used to effectively and conveniently solve the cross-channel problem. The simulation results show that the judge of the same radiant point can be performed effectively when the parameters of the receiver are stable, and while SNR is greater than -3dB, the parameter estimation algorithm is of high precision, and the relative error of pulse amplitude is less than 7%.

Abstract:A novel design for patch antenna, which can obtain low radar cross section (RCS) and high gain performance simultaneously, is proposed on the basis of metamaterial superstratum. The superstratum consists of two metallic layers with different patterns on both sides of a dielectric substrate. Low reflection and transmission are obtained from the upper surface which can absorb most of the incident wave to reduce the antenna RCS. The bottom surface, which has partial reflectivity, is used to construct a Fabry-Perot resonance cavity with the ground plane of the patch antenna to improve its directivity. Simulated and measured results show that the proposed antenna can achieve an obvious RCS reduction in a broad frequency band ranging from 2 to 14 GHz and the maximum reduction can reach 28.3 dB, and yet the gains of the antenna are all enhanced and some are even enhanced maximally by 4.3 dB in the working frequency band compared with the original antenna.

Abstract:The paper proposes a miniaturized, high-gain, ultra-wideband and end-fire antenna which covers 2.7～18.3 GHz band to overcome the large size and small forward gain at low frequency of conventional Vivaldi antenna. By adding Y-shaped apertures on both sides of the radiation patch, the surface current of antenna converges near the through line，so the radiation property is improved, including the impedance bandwidth, the antenna gain and the end-fire effect. The size of the antenna is only 25 mm×25 mm×1 mm, thus achieving a significant miniaturization. The gain of low frequency part (2.7～8 GHz) is increased to a maximum value of 3.5 dB compared with the original antenna. The test result of the fabricated antenna demonstrates the reliability of the design.

Abstract:For the weakness of the frequency-domain narrowband interference suppression methods, the improved adaptive multi-threshold interference detection algorithms and the application of generalized extended approximation algorithm in interference suppression have been put forward. The improved algorithm used the spectrum to remove the interference continues after detection frequency interference detection effect has been significantly improved; there is an element of constraint extension function approximation algorithm, simple structure ,approaching ideas by extension, reducing the time-domain waveform signal processing frequency interference distortion. Matlab simulation verifies the performance of the algorithm throw the contrast of BER, and it is improved the interference detection performance and interference dispose ability of the improved algorithm.

Abstract:Let q=3l+1 and q=3l+2 be prime powers. The maximal designed distances of imprimitive Hermitian dual containing q-ary narrow-sense (NS) and non-narrow-sense (NNS) BCH codes of length n=3(q－1)are determined, and a series of NS and NNS BCH codes are constructed and their parameters are computed. Consequently, two families of q-ary quantum BCH codes are derived from these BCH codes. Some of these quantum BCH codes constructed from NNS BCH codes have better parameters than those quantum BCH codes available in the literature.

Abstract:When the loads in three phases are unbalanced, the traditional inverter can not make the output voltages balanced. So a 3-phase 4-leg structure is used for controlling the zero-phase voltage and current to reply the unbalanced loads. In this paper, by decoupling the 3-phase output voltage and adding in the double loop control of voltage and current, the space vector modulation to the inverter control stability is enhanced and the dynamic response characteristic is improved. And then, Matlab/Simulink is applied to modeling and simulating, and the simulation model is set up which make the simulation achieve a desired effect. According to the algorithm, DSP is programmed and by observing SVPWM waveform, reasonability and availability of the algorithm are verified.

Abstract:Assuming that the distribution of individuals and the competition mode of individuals are for the same resource, interspecific competition models dependent on distribution of individuals are established in a bottom-up manner for two species in a habitat according to the site-based framework model. The assumed distribution of individuals has three types, i.e. Poisson distribution, the negative trinomial distribution and the independent negative binomial distribution. The assumed competition model of individuals in the same resource has three kinds, i.e. scramble competition, contest competition and intermediate competition. According to the combination of competition models of the two species and the distribution of individuals, various interspecific competition models can be derived. In this paper, two different interspecific competition models with the negative trinomial distribution are established, within which the competition modes are of scramble vs. contest and scramble vs. intermediate competition s respectively.