Abstract:With simplified one-dimensional low magnetic Reynolds number MHD equations，this paper involves study on the numerical simulation of ideal Faraday MHD power generation channel，analyzing influence that the change of electromagnetic parameters and channel geometry parameters have on the performance of MHD power generation channel. Results show that MHD power generation channel can reduce flow velocity and total temperature，and extract energy effectively. However, it can inflict losses upon total pressure because of electromagnetic irreversible and Joule heat effects. Increasing of magnetic field strength and electric conductivity means role in enhancing of electromagnetic. A reasonable expand channel can efficiently refrain from static temperature, flow velocity and total temperature at the exit, and get the favorable influencing factors of electromagnetic. Effect of decreasing in outlet velocity, total temperature as well as total pressure and increasing in extracting-energy-rate can be received by enhancing parameters such as magnetic field strength, electric conductivity. Otherwise, magnetic field strength and electric conductivity should be diminished.

Abstract:A dynamic terminal sliding mode control system designed as to the problem that permanent magnet synchronous motor (PMSM) is vulnerable to external interference in the process of operation. Nonlinear function is introduced into the terminal sliding mode control in the design of sliding hyper-plane, thus making the tracking error in sliding surface in the limited time converge to zero. Dynamic sliding mode control method can be used to eliminate the chattering phenomena caused by the discontinuity of controller switch function. Based on this, using good approximation of fuzzy system to estimate the uncertainties and external disturbances of PMSM a fuzzy technique dynamic Terminal Sliding Mode Control method is proposed. The use of the method can effectively reduce the chattering phenomena caused by upper bounds of uncertainties. Simulation result demonstrates that the system is good in tracking performance, non-sensitive to the parameter changes and of strong robustness.

Abstract:By using the arc discharge, the oblique shock wave is induced in a position of the convergent-divergent inlet, making the supersonic airflow in the diffuser deflect after passed through the oblique shock, which produced thrust vector. On the bases of existing mathematical model of the coupling of arc discharge and supersonic flow field, numerical simulation on the factors of discharge area, temperature, position, and nozzle pressure drop those affect the flow deflection has been performed under the flow Mach number 1.5. The preliminary experimental on arc discharge inducing jet flow deflection verifies the feasibility of the plan, and the correctness of the mathematic model，the result of the numerical simulation lays the theoretical basis for the subsequent experiment research.

Abstract:The risk computation model and optimal strategy for radio frequency (RF) radiation on aircraft formation is investigated by analyzing the model of aircraft formation and the mechanism of electronic counter measures (ECM) between aircraft airborne radar and intercepting receiver. Regarding Schleher intercept factor as the risk index of ECM between aircraft and intercepting receiver, the factor is extended to the simple formation in the case of two aircraft, and the RF radiation risks of different formations are also compared. The computation model of Schleher intercept factor of RF radiation risk in the case of multiple aircrafts is presented by establishing the appropriate reference coordinate system. Regarding Schleher intercept factor of aircraft formation as the performance index, a stochastic optimal model is established for minimizing the RF radiation risk of aircraft formation. By analyzing the characters of performance index and using the basic inequality, the conclusion that the less the variance of the positions of aircraft formation in the flight airspace is, the less risk the RF will have can be obtained. Based on the conclusion, a simplified model of risk control of RF radiation in the case of multiple aircraft formation is established. Finally, the formation scheme of approximate optimization is proposed by the computer simulation in the case of 12- aircraft formation.

Abstract:For analyzing the takeoff and landing process of airplane accurately and finding the basis of the runway length design, the differential equations for takeoff and landing running process are established and resolved. The running performance model is built by Simulink program based on the differential equations. The Simulation model is validated to be effective by the contrast in speed and acceleration data, the theoretic results and the simulation results. The running process of the airplane is analyzed by using the model; the results show that the takeoff process and landing process without drogue parachute could be approximately considered as a uniformly accelerated rectilinear motion, the landing process with drogue parachute is relatively complicated. Finally, the affections of three main factors are studied and the results show that the relationships between running length and airfield altitude or wind speed are approximately linear, the relationship between running length and attack angle is nonlinear and the minimum point of running length appears at the attack angle of 8°. The analysis of airplane running state can be taken as basis for runway length and taxiway high speed exit position design.

Abstract:The key problems of volleying air combat simulation under electronic support are researched against the new combat modes and objects in future air combat. The air combined formation consisting of fighters, unmanned aircraft and electronic warfare planes is the main study object. With object-oriented technology involved, the use case diagram and class diagram of UML are used to analyze the static function structure of volleying air combat and the interactive model, activity transition model are established through the sequence diagram and activity diagram. The combat flow is explained systematically. Meanwhile, the modeling of electronic countermeasures is just the point. Finally, a simulation system of volleying air combat is realized. Simulation experiment shows that this simulation system can provide the experiment platform for combating efficiency evaluation of aviation electronic countermeasures system.

Abstract:The track forecasting model of TBM in the middle course is one of the key models in the system of missile defense, and is a basis for the commander to control the threat situation、carry on the battle programming and design the battle scheme. This paper first explains the common coordinates and their conversions used in the forecasting process; then puts forward the particular process and computing method of the relative parameter in the model. Finally, through the simulation analysis, the conclusion got shows that this method is effective and practicable in the project simulation, which provides a technique support for the task programming and battle scheme's establishment.

Abstract:The use of traditional algorithms cannot obtain a well-focused and cross scaled ISAR image for non-uniform rotating targets. To solve this problem, a method is proposed to estimate the rotating parameters when targets undergo non-uniform rotation. Firstly, the ratio between the angular acceleration and the angular velocity is estimated by one dimension search. By non-uniformly sampling the raw profile sequence according to the estimated ratio, the phase error caused by angular acceleration can be compensated and a focused ISAR image can be obtained. Based on the rule of image quality, the rotating velocity of the resample signal can be estimated by another one dimension search. Furthermore, the scalar of cross-range can be obtained. A focused, cross-range scaled ISAR imaging can be obtained for non-uniform rotating targets based the proposed algorithm. Experimentations with the simulated and measured ISAR data demonstrate the effectiveness of the algorithm.

Abstract:Missile is a kind of costly and long-stored equipment. The state of missile can be monitored effectively, but the broken-down time can't be forecasted. It is needed to use the test data logically for assessing the storage reliability. Now the missile field test data can't be fully used that cause the problem of superfluous or deficient test. By investigating the test and storage type of missile components, 4 kinds of missile field test data-acquisition projects are brought forward. The advantage and disadvantage of the projects are analyzed. The failure of missile can be ascribed to degraded capability. It is better to use the approach about degradation data analysis based on the pseudo life distribution to assess the reliability. According to the approach, an emulator in which the data of project 1 is used is given. The results validate the validity and practicability of the project.

Abstract:In order to further improve the precision of estimating the instantaneous frequency in radar signal processing, a new Morlet wavelet atom, based on the known Morlet wavelet atom to extract the signal wavelet ridge feature (WRF) is put forward. By analyzing the wavelet ridge principium and the qualifications of wavelet atom for extracting the WRF rightly in-depth, the WRF of radar emitter signals can be extracted. Consequently, the instantaneous frequency can be estimated. The new -Morlet has better performance of time-frequency colligation character in contrasts with the known Morler wavelet atom. At the same time, the iterative algorithm of estimating the instantaneous frequency is analyzed, which is based on the wavelet ridge principium. The computer simulation experiment results also show that the new-Morlet wavelet atom has better performances in detecting WRF and counteracting noise than the common Morlet wavelet atom. The experiment proves the effectiveness of the method.

Abstract:This paper defines the operational readiness of terminal high altitude antiballistic missile equipment under different maintenance systems, introduces how to calculate the operational readiness rates of equipment and establishing a repair delay time model. By utilizing the repair delay time to value the influence of maintenance systems on operational readiness rates is judged. Monte-Carlo method is used to simulate the model, and the demands of different maintenance systems on the repair delay time under the set operational readiness rates are got. The sensitivity analyses of MTBF and MTTR are made to validate that the parameter variety bound is reasonable. The results indicate that two-level maintenance is more beneficial to enhancing the operational readiness. The conclusion can be a reference for building terminal high altitude antiballistic missile equipment maintenance system.

Abstract:The combined over-complete dictionary is proposed based on the theory of sparse decomposition to achieve signal separation and reconstruction which is intensively studied and has been widely applied to many areas in signal processing. The combined over-complete dictionary is composed of many over-complete dictionaries with single feature, contains enough information of decomposed signal and makes complex signal more sparse, so separate signals can be separated and reconstructed much better by the basis pursuit algorithm. The simulation results show that the proposed idea of the combined over-complete dictionary is efficient to the complex signal reconstruction and separate signal separation and reconstruction.

Abstract:For land-to-air missile weapon system simulation, most problems can be abstracted as the problems on the relationship between the target and the given region (polygon). In this paper, the conceptions of Rotary Function and correlative edges are proposed. By integrating rotary function with correlative edges, a new algorithm of point in-out polygon is put forward. The new algorithm transforms the relationship between a point and a polygon into that between a point and its correlative edges. This paper firstly finds the correlative edges of the point, then, calculates the value of the rotary function of the polygon that assembled by the point and its correlative edges, finally, by analyzing the value of the rotary function, the relationship between point and polygon can be sure. Because lots of operations of intersection are avoided, the efficiency of the algorithm is raised radically. The use of the new algorithm can effectively and simply solve the critical position problems in the traditional algorithm. Software implementation verifies the high robustness and efficiency of the new algorithm. The model constructed in the paper is strong in reuse for multi-type land-to-air missile weapon system simulation, and the study in this paper is important to avoid overlapped study and development.

Abstract:The extraction of vision key-points decides directly cognitive navigation efficiency for UCAV. In order to extract high robust key-points for UCAV, an algorithm named multi-quantifying scale invariant feature transform (MQ-SIFT) with key-points optimization is proposed. According to the deficiency of SIFT algorithm in analogue feature vectors' balance and correct matching score, a method combining the multiple value quantifying and reshaping operation is presented to quantify analogue feature vectors. The analysis and simulation results verify the better properties of this method. Furthermore, in order to perfect the property of MQ-SIFT with fewer robust key-points, the optimization rules are discussed, and an iterative cross-Euclidean distance search method is proposed to search the maximum connected set. Simulation results show that MQ-SIFT algorithm has higher correct matching score with signal-to-noise (SNR) above 10 dB, and their matching score can meet the requirements of cognitive navigation system.

Abstract:To solve the problem of out-of-sight communication in remote ground-air communication, an out-of-sight air-ground communication scheme is proposed, which is relayed by multi-elliptical orbits small satellites. At first, orbit parameters of small satellites are designed and average coverage rate of target area is certified 99.41% by using medium ellipse orbit constellation which consists of 4 satellites. Then work principle and link propagate characteristic of out-of-sight air-ground communication system is studied and link transceiver parameters are designed on that basis. The simulation results show that the use of the proposed system in communication is without distance limit, and the system has the advantages of good communication effect, good anti-destroyed performance and low cost.

Abstract:DV-Hop algorithm is a typical range-free localization algorithm in Wireless Sensor Network (WSN). For the problem that there is great difference in location errors and positioning time because of the different factors settings for DV-Hop algorithm，the algorithm parameters including the number of nodes, average network connectivity and monitoring areas which impact on the location error and positioning time are analyzed and simulated. In view of energy and the cost restriction, and through analyzing the simulation results the conclusion that the average network connectivity and the numbers of nodes have great influence on location precision and positioning time of DV-Hop algorithm respectively. Theoretical analyses and simulation results show that the optimized parameters effectively reduce the node location error at the different monitoring areas based on the low energy consumption of DV-Hop algorithm.

Abstract:Aimed at the problem that MANET routing protocol could be only simulated in software which lead to a inaccurate result, and taking a large scale MANET routing protocol SPDSR for example, a method of implementing MANET routing protocols in Linux OS is put forward. This method lays a foundation for building a practical MANET test. Based on the study in Linux original routing architecture, by using net-filter framework and TUN/TAP technology the functions of packets intercepting and user space buffering are achieved, then the SPDSR routing algorithm is started. With establishing a route check module, which delivers route status to user space through and updates route table timer, a faulting delete operating for past routes will be avoided. Finally, the SPDSR protocol has been successfully added in Linux. Practical network test result shows that the implementation of SPDSR based on Linux is able to build and maintain route in a wireless mobile ad hoc net-work, as well as meet the needs of engineering application.

Abstract:Based on high-order cumulates, a novel recognition algorithm is proposed for LCP-GLSTBC (Group Layered Space-Time Block Coding) OFDM (Orthogonal Frequency-Division Multiple) signals to distinguish multi-carrier modulated signals (OFDM) from single-carrier modulated signals (MPSK and MQAM). The proposed algorithm can be used to directly process inter-frequency signals without the prior information about the transmit signal and the channel noise. Simulation results confirm the validity of the proposed algorithm and show that over 90% correct classification rate could be reached when SNR is above 5 dB.

Abstract:In this paper, a nonlinear dynamic model derived from engineering is investigated. The dynamic characteristic is analyzed by using the geometrical theory of ordinary differential equations. The Tacoma bridge is taken for example, the quantitative analysis of the nonlinear dynamical model of a flexible structural bridge under the unsteady aerodynamics from engineering by harmonic balance method is made based on the qualitative analysis of the types of fixed points and the existence of periodic motion. And the approximate periodic solution is obtained. Finally, the approximate analytical results are verified by numerical simulation. The results show that the analytic results are close to the numerical ones in accord with the qualitative analysis when the wind speed is in a certain region of parameter. Here, the results in this paper are valuable in the calculation of vibration engineering and theoretical design, since the long-time periodic oscillation is likely to cause the fatigue of structure, even probably effect severely the structural safety of bridge.