Abstract:In order to research the change regulation of aerodynamic center based on a variable forwardswept wing (VFSW) configuration with a slide way sweeping , by adopting a format of NS control equations with the method of finite volume method, the aerodynamic center on the VFSW configuration under different conditions is numerically simulated, and the location of the aerodynamic center is obtained. The change regulation of aerodynamic center with the sweep angle in the same Mach number and the change regulation of aerodynamic center with Mach number at the same sweep angle are summarized. The corresponding reason is analyzed through surface pressure contour over configuration and pressure coefficient on the wing. The results show that the aerodynamic center moves backward slightly and then reverses heavily with the increase of sweep angle in the same Mach number. With the increase of flight Mach number, the aerodynamic center moves forward in a tolerance interval at the same sweep angle. When the VFSW configuration executes corresponding missions, this makes an aerodynamic center moveable in a small scale.

Abstract:Aimed at the problem of "miss" in the traditional GPS navigation system, a new algorithm for selflocalization is presented by taking the visual navigation as a novel navigation manner without compute camera calibration and any remote sensory information, and the position can be well estimated on the property of projective geometry and relation of geometry. Firstly, the target in the plane is located with the target's position to realize the vision selflocalization. The conclusion demonstrates the effectiveness of the model. The experiments show that the method can effectively eliminate the position, and the maximal different value is 0.01 m. A novel thoughtway with simplicity, real time and high precision is provided for vision selflocalization of UAV is provided．

Abstract:Aimed at air route planning problems in complex environment, a route planning optimization method without threat based on the fundamental ant colony algorithm is proposed. The use of this method enhances the descriptive ability of the real flight circumstance to improve the effectiveness of route planning by reconstructing the route planning target function and comprehensively analyzing the information of terrain and threat in aircraft flight environment, including the factors such as route distance, time, fuel, cost and threat evasion ,etc. Still, the use of this method can save algorithm time and enhance efficiency of optimization by improving distance heuristic factor to introduce heuristic direction. The simulation results show that the use of this improved ant colony algorithm can save 10% of the optimization time and reduce 10odd iterative times compared with that of the fundamental ant colony algorithm.

Abstract:The basic connotation of multitarget attack in air combat is analyzed, and an attack sequence and direction planning based on virtual navigation path is proposed. Firstly, the impact of the attack sequence and direction is clarified. Secondly, the planning of attack sequence and direction is equivalent to the programming of the virtual navigation path, the planning space is established, and the principle of navigation path programming and the indexes of feasible route are presented. Then, the concrete coding and the solution methods are given based on the particle swarm optimization (PSO) algorithm. Finally, the computer simulation shows that the method proposed above is effective in solving the problem of the attack sequence and direction planning of multitarget attack, and simultaneously the use of this method can ensure a higher survivability for the fighters in the process of implementing multitarget attach tactics.

Abstract:In order to study the influence of different course shortcut and height on the dynamic RCS of aircraft and find out the universal model which can describe the dynamic RCS, the dynamic RCS of aircraft is statistically analyzed in this paper. By using a quasistatic analysis method, the dynamic RCS of aircraft is simulated at the different course shortcut and height, and the influence is analyzed respectively. Three statistical fluctuation models are used to match the RCS statistic data and the difference between different course shortcut and height, and the difference of the modeling results are compared and inspected by KolmogorovSmirnov test. The goodnessoffit test results show Lognormal distribution is a universal distribution to describe the dynamic RCS beyond the limitation of course short and height. The results of this paper are of significance to the early warning and detection of noncooperative target and provide a theoretic support to the advance of radar's function.

Abstract:At the basis of analyzing the target assignment mechanism, the discussion about the suitability of target assignment in the task of air and missile defense is given. Because the ballistic missile targets have clear goals and need short response time, a distributed mechanism is adopted and analyzed through modeling with market bidding algorithm; while the aerodynamic targets have more uncertain factors and need longer response time, a centralized mechanism is chosen and analyzed through modeling with improved genetic algorithm. Combining two mechanisms finally, the mixed mechanism of dynamical target assignment is presented for the task of air and missile defense. A simulation example is demonstrated，and the result shows that the mixed coordinate mechanism could deal with large numbers of ballistic missile targets and aerodynamic targets. The mechanism also could deal in some ways, when saturation attacks coming.

Abstract:Detection of super-low altitude target is a hot point in current military confrontation. Multipath Interference is a difficult problem nowadays. To solve the problem,'G-Brewster' is put forward from electromagnetic scattering. The elements of rough surface are thought about and the best angle is found to detect the target. To get the echo ,the target is meshed and PO+MEC is used to calculate the scattering field, and then the reflection coefficient is derived. On the basis, multipath echoes are gotten. The condition of the existence of G-Brewster is studied out, and the angle that strength of multipath interference is lest is found out. The discipline of G-Brewster on environment is posted. The study will lay a foundation of super-low altitude target.

Abstract:Considering mandatory synchronization，torque coupling and parameter drifting among two brushless DC motors with synchronous shafts，a novel two- motor torque balance control scheme based on fuzzy control is presented. A double loop-closed control of speed control and torque balance is realized simultaneously with meeting the speed control and power balance control system，in which torque servo master-slave control method is used. In speed control loop, the result of comparing given speed and the feedback speed of brushless DC motor gets access to the speed regulator to obtain the unified torque command. The other result of comparing the given speed and the torque feedback of brushless DC motors comes into the torque regulator to constitute two torque closed loops to rapidly follow the unified torque command. In Matlab/Simulink environment，the model of two motors torque balance control is built and a simulation of the working state of motors is conducted in normal and abnormal electrical parameters. The simulation result shows that the proposed scheme is valid.

Abstract:By the use of the principle of compressed sensing (CS) theory which is based on the sparsity or compressibility of signals, a new sparse representation for azimuth is proposed through the analysis of synthetic aperture radar echo signal. On this basis, a SAR echo signal processing method is obtained and a 2D SAR imaging algorithm which achieve a fire-new data collection and coding of signal is established. The use of this algorithm not only suppresses the side lobe effectively but also enhances the resolution of imaging target to a certain extent, and simultaneously needs less amounts of data for imaging, which provides an efficient path of decreasing the data rate of high resolution synthetic aperture radar. The feasibility and validity of the method proposed in this paper are tested through processing both simulated data and real radar data.

Abstract:To meet the real-time simulation of ballistic target radar echo precision requirement is a stronger comprehensive project, it is a key to the target detection and recognition. In this paper, a calculation formula of a large ballistic target in explicit RCS arbitrary angle of sight is given under microwave frequency based on GTD and PO method. The results computed by using this method agree with that by using the FEKO software and the calculation speed is extremely high. Using the data obtained by this method to realize the High Resolution Range Profiles (HRRPs), the results of simulation and theory are in good agreement with each other, and can meet the need of real time simulation precision of radar based on reentry ballistic target echo signal of target electromagnetic scattering characteristics.

Abstract:In view of the facts that fuse target near-field scattering characteristics is affected by series of factors such as antenna pattern, target's partly illuminated and missile and target encounter state, and calculating process is complex, in this paper, a real-time simulation method of target near-field scattering characteristic is presented based on FEKO. Then, a model of missile and target encounter is established in view of the characteristic of fuse operation phase, fuse target near-field dynamic scattering characteristic is calculated real-timely. The result shows that the near-field scattering intensity has something to do with the target's illuminating parts and the missile miss distance. The smaller, the missile miss distance, the stronger, the scattering intensity, and the scattering intensity will present a big undulation cause in the different illuminating parts when a missile is very close to target.

Abstract:B-values processing algorithms is the core of GNSS landing system. In multiple reference consistency check, the rule of maximum likelihood estimation is used in traditional processing method of B-values, so some correlativity exists in the traditional B-values process, which is easy to cause the problems such as the difficulties in distinguishing between fault sources, the low fault detection rate. To solve these problems, this paper studies the B-values processing method based on Kalman filter. And the use of the new processing method can improve the performance of the system through the establishment of filter model. Experiments are done and the results show that the new processing method based on Kalman filter is very effective in fault detection, and the use of the method enhances system availability level. In the end, the fault detection rate is increased by nearly 20%.

Abstract:To solve the problem of gain error and timing-skew mismatches among channels of time-interleaved analog-to-digital converter（TIADC）system, a joint measurement method of mismatches error is proposed. By making full use of the characteristic of the test signal, this method can measure two kinds of errors simultaneously. Compared with the existing algorithm, the measurement algorithm is simple and more effective. According to the principle of timing-skew, the compensation method of fractional delayed filter based on Farrow structure is designed. Because of the problem of limited Nyquist bandwidth of Farrow structure, a multi-channel compensation structure is designed. After compensation, the output SINAD of the system is increased by at least 25dB.

Abstract:Aimed at the problems of FHN model that the detection of UWB signals is restricted by the relationships between system parameters and aperiodic stochastic resonance (ASR), i.e. the known UWB signal and the adjusted intensity of noise, the cross-correlation function is derived, and a method of ASR FHN model with adjusting system parameters is proposed based on the new cross-correlation function. The proposed method is used to detect UWB-IR signal. The simulation results show that the unknown UWB-IR signal in high noise can be accurately detected by the proposed method applicable to detect UWB signal under condition of non-cooperation in low signal to noise ratio(SNR)

Abstract:In high-speed network environment, it's very important to extract elephant flow timely and accurately for cognizing behavior and law of network. In order to reduce the elephant flow measurement missing rate and overmuch occupation of SRAM, an improved algorithm based on LEAST is proposed. By using LEAST elimination mechanism for discarding the mice flow, the elephant flow can be protected. And Window-Reserve strategy is adopted to ensure the fairness of identifying and measuring elephant flow. Finally, through the comparison between the simulation results and the actual flow data, the result shows that the new algorithm has a higher measurement accuracy and is more practicable, and the elephant flow on the average measurement missing rate is reduced to 0%~0.13%.

Abstract:In order to acquire a better extraction of 3D features of building and aimed at the problem that the eight neighborhood search method of extracting 3D features of the building with a sloping roof is not good in precision, in this paper, a smaller threshold elevation difference is set first and then buildings are extracted by using the eight neighborhood search method to improve the accuracy of the algorithm for the extraction of the buildings.The graded differentials in four directions around the point are used to complete the secondary extraction of the feature points cloud to increase the full rate of the extraction of the buildings.The building patch has a large surface area of the chip features and represents the actual number of communicating with the interior point of scene size. Setting of a reasonable threshold can eliminate the vegetation patches and other surface features patches.The results show that the use of the improved method can obviously increase the accuracy and integrity rate of 3D features of building extracted from the mixture of the point cloud and the adaptability of the method in extracting the sloping roof is improved.

Abstract:Aimed at SAR raw data, this paper proposes a high capacity information hiding algorithm based on pixel pair matching conducted according to the secret data. By using an extraction function, different combination of SAR real part and imaginary part are mapped into a secret digit in an n2-ary notation system, and the optimal combination is chosen for a data block with the smallest MSE. Thus, the distortion caused by information hiding can be ignored for SAR imaging. Compared with the other similar algorithms, the PSNR of the proposed method increases 0.7 dB on average under condition of the same capacity, and high security is achieved with the help of various combinations.

Abstract:Aimed at the problems in the SNR estimate method of the subspace that error is excessive in calculating signal subspace dimension and this makes the estimate precision low under conditions of low SNR, in this paper, a new robust SNR estimate method is proposed applicable to the subspace SNR estimate of small size data through the analysis, the simulation, and the determination of the subspace method under conditions of the finite sample date. The results show that the estimate error can be decreased by 0.3~2 dB by use of the new method in low SNR and short data samples environment

Abstract:Based on the federal filter idea, the kinds of information from airborne data-link, photoelectric sensor and radar are fused to solve the problem that radar is liable to suffer from deception jamming in the process of tracking. First of all, measurement feature of the radar is analyzed, which is disturbed by using the different deception jamming methods, and the detection method of airborne multi-sensor jamming is studied. Combining with interacting multiple models, time unification, information equivalence transformation, and information distribution, this paper utilizes the federated filter for building an airborne multi-sensor anti-deception-jamming information fusion algorithm. The result of the computer simulation shows that the deception-jamming to radar can be detected, and the true target of radar- tracking can be ensured effectively by adopting the algorithm.

Abstract:After analysis of Tacan signal structure, an idea of adding data-broadcast function on Tacan beacon is proposed in view of low occupancy rate of uplink channel. The maximum time can be used for broadcasting data per second is estimated according to response probability. A method of broadcast identification code and geodetic coordinate of beacon is then designed, in which information is encoded as pulse train and inserted after main reference pulse group. The simulation and analysis results show that the method has no influence on angle measurement performance, and the bandwidth of signal eradiated by beacon maintains within 300 kHz. The response probability of beacon is merely reduced by 0.2% when the data broadcasting function is added.

Abstract:In order to investigate the efficiency of atmospheric pressure plasma jet （APPJ）treatment on PET films in terms of inducing free radicals and subsequent grafting polymerization, Electron Spinning Spectroscopy (ESR）technique is used in this paper to test and analyze the free radical outcomes and their aging phenomenon. The correlation between the ESR results and grafting ratio change trend for different samples is then discussed and analyzed. The results show that pure He gas APPJ is more easily to make free radicals generated on PET film and the free radical concentration is increased with the prolonged treatment duration. The stability of trapped free radicals on PET films varies obviously with different storage conditions. Samples with higher free radical concentration could also gain higher grafting ratio.

Abstract:Aimed at the problems that the study is not enough on the shock wave damage assessment methods of the target in building and the selecting aiming point is difficult, this paper proposes a concept of the volume-damage probability assessment, sets up a simulation model and gives out a computational method of the volume damage probability through the research on the shock wave propagation in buildings, and based on the gridding method, also presents a discrete point method to compute the three-dimensional damage probability. Finally, the result shows that the model accords with the fact, the disperse-point method is effective, and high in precision. Thereby, the concept of the volume damage probability assessment will be of great value to us in our research shock wave damage work and the precision guide missile and selecting aiming point.