Abstract:The airworthiness working in the development of military aircraft is a great challenge for the current military aircraft development and management system and only a little experience is suitable for our aviation industry mechanism. In this paper, the current condition of airworthiness system for the development of civil and military aircraft home and abroad are introduced, the primary thought on and technology approach to the development of airworthiness work for the home-made military aircraft is discussed. Finally, the regulation、organization、management and basic technology to be solved urgently for the military aircraft airworthiness are proposed. All of these provide a beneficial reference for the establishment of scientific and perfect airworthiness technology system for the home-made military aircraft.

Abstract:The performance of Support vector machine (SVM) is affected mainly by model parameters, but there is no special method for the model parameter selection of SVM based incremental learning. A new method is proposed in this paper, i.e. taking robustness as criteria for performance evaluation of incremented learning, the range of solution space is designed by fitting error and scale factor, then the gradient descent algorithm is used to search the parameters. The experiments with this new method are made on the Logistic model regressing and aero engine vibration monitoring, and the comparison of this new method with the genetic algorithm and the gradient descent algorithm is made. The result indicates that the use of the proposed method can take full advantage of the results of historical learning, thus the solution space is narrowed, and iteration steps are reduced.

Abstract:The linearized C-W equation is used very expediently, but it has the problem of inaccuracy. An improved equation based on C-W equation was presented, which can describe the formation flying more accurate. Firstly, the derivative process of C-W equation was analyzed and the inaccurate reason was find out. Then parts of contents were adding and re-derivation, which has been ignored in order to simplify the equation in the original derivative process. And lots of mathematical transformations were used to reduce the new equation. Finally, a set of linear differential equations with constant coefficients was given, which can improving the precision without increasing the complexity. Simulation shows that in the condition of circular orbit, the accuracy was improved a lot comparing with the C-W equation, while in nearly circular orbit, the long-term error of C-W equation was eliminated.

Abstract:Flow fields of 2-D shock vectoring nozzle are calculated by the finite volume method based on 2D Reynolds average Navier-Stokes equations, RNG turbulent model and considering the variation of specific heat at different temperature. The results show that there has been some changes of the nozzle flow fields such as upper moving of the shock wave, the abatement of the shock wave amplitude and the increase of the velocity of the nozzle outlet compared with the calculation of constant specific heat. By further analyzing, the thrust coefficient, the thrust vectoring angle and the vectoring effectiveness all have increased in contrast between the variable specific heat calculated results and the constant specific heat numerical results.

Abstract:In order to reveal the mechanism of nanosecond pulse plasma flow control and then enhance the boundary layer control ability of plasma aerodynamic actuation, the electric characteristic and the body force of plasma aerodynamic actuation of different time scales are diagnosed experimentally. The results indicate that the inceptive discharge voltages for microsecond, millisecond and nanosecond pulse actuation are nearly the same, but the maximum discharging current of nanosecond pulse actuation is 4 A, which is much higher than that of the microsecond and of the millisecond. The body force will increase with the rise of the actuation voltage; the differences of the vertical components of the body force induced by plasma aerodynamic actuation of different time scales are little, but the horizontal components induced by millisecond and microsecond actuation are greater.

Abstract:A mathematic model is established, with focus on the control of tailplane actuator servo system, based on control theories. Considering its nonlinear and intermittence, a fuzzy-PID control method is brought forward based on fuzzy theory, and the design of a fuzzy-PID controller has been finished, then it is compared with conventional PID control and P control, finally system simulation is conducted with SIMULINK under the effect of unit step signal. The result shows that the fuzzy-PID control has a better capability in speediness, quick response and anti-jamming, it has a good dynamic characteristic and dual advantage of the fuzzy control and the PID control which enhance the integral property of the tailplane actuator servo system and obtain a good control effect and can better meet the requirement of the system.

Abstract:In view of the problem of the terminal real-time display of the platform trajectory in the data-link aircraft simulator, the trajectory equations of circling maneuver and looping maneuver are constructed, and the general processing of maneuver is designed. Establishing AIMM time delay -compensation model based on the timestamp makes the Aircraft movements show keep pace with the plane state of actual combat under the network load. Finally two maneuver scenes are set to demonstrate the flight mobile track, which verifies that the visual platform can effectively simulate aircraft hovering and looping, realizes the ground command post real-time monitoring the analog aircraft flight state, and lays a foundation for air combat simulation training.

Abstract:For identifying the target and estimating its attack attempt early to improve the intercepting efficiency in anti-missile battle, the information support about target is necessary and provided by space-ground warning system. Using an effective matching model can achieve detecting and affirming the target property quickly based on the information of target from the space-ground warning system. This text emphasizes on the matching model and the algorithm of target property and elementarily realizes the matching model of target property using emulation method based on the measuring model of space-ground warning system. The result indicates that the matching model and algorithm are of better value to application and can give some reference to the command and control system in construction and perfection.

Abstract:For the requirement of Target type recognition in air defense combat process, this paper points out the limitations of traditional and generalized Grey Relation (GR) models in data processing, and then an improved GR model based on entropy-weight method to recognize the unknown target type is established. Firstly, in order to make full use of air targets' data exactly, the method of entropy-weight is introduced in this model to determine the index weight. Secondly, the Certainty Factor is used instead of the absolute value to more accurately describe data errors between different serial numbers. Finally, the discretization of the output of this model is made, which enhances the ability to distinguish different target types effectively. Furthermore, examples are taken to validate this model, the results show that the model is accurate, simple, high in recognition rate and of great value in application.

Abstract:The anti-missile battle case is the precondition and foundation of generating the anti-missile scheme, optimizing resource and improving the validity. This paper, firstly, analyzes the position and application of the battle scheme in the BM system; then, by combining the characteristics of CBR, deeply analyzes the four key problems of battle case's expressing, index, matching, adjusting and studying. Finally through a matching example, a conclusion is reached that the generation technology is effective in application to the BM system, which can provide a decision support and theory basis for the determination of a real time anti-missile scheme.

Abstract:Out-of-sight communication in ground-air communication is a difficult problem; especially the effective implement of the out-of-sight communication on fighters is more difficult. In order to implement ground-air out-of-light communication, a small single orbit satellite net is proposed. The orbit height of the small satellite is low, so both the communication link loss and the communication transmission time delay are smaller, thus, the requirement in quality for the antenna in fighters is decreased. In this way, it is possible to realize the direct communication between fighters and small satellites. Several satellites in one orbit grouping a net can realize continuous communication cover for parts of an area, so can satisfy the needs for the out of sight communication to parts of an area. The developing period for the small satellite is short, and the launching method of the small satellite is flexible. The orbit characters can also be designed according to the needs of the communication area. These characters of the small satellite accord with the military needs. In this paper, the orbit characters including the orbit height, the quantity of the small satellite, center departure rate, communication cover range, etc are studied.

Abstract:The deep space optical communication links are very far away, so a very harsh power budget is required. Since there are many factors affecting the feature of communication link, a very complex trade-offs consideration is often given to the power budget. The paper emphatically analyzes the link distance, optical antenna diameter, beam divergence, atmospheric channel loss, optical system loss, detector sensitivity and other factors affecting the link equation, signal to noise ratio (SNR) of detector and bit error rate (BER) of communications. Simultaneously the paper proposes a new method of budgeting transmission power combining the link equation, SNR and BER. An outside demonstration experiment for the ground-ground optical communication of 7km, is carried out, the losses of the atmospheric channel and optical system are tested. Then again many experiments in indoor labs, test the beam divergence and detector sensitivity are performed. The experimental results and theory analysis show that the budget method is feasible in application to the deep space optical communications.

Abstract:To address the ambiguity of information and uncertainty in the image-guided application, a Multi-source information fusion technology is proposed for infrared/visible dual-mode compound imaging guidance. With augmented variance ratio of two classes, an on-line adaptive feature selection scheme is applied to selecting the distinguished attributions in the infrared and visible images. The results of object tracking are yielded in infrared/visible images respectively based on a particle filter algorithm; by introducing the quality metrics factor of tracking in single-mode image sequences, a weighted fusion strategy is employed to achieve the robust tracking in image sequences, the experimental simulation results has verified the effectiveness of the scheme.

Abstract:Group key agreement is one of the important means to ensure group secure communication for wireless networks. In 2007, Tseng et al. proposed an efficient group key agreement protocol in wireless mobile environment. In this paper, by analyzing the security of the Tseng's protocol, the authors have found that the Tseng's protocol is not an authenticated protocol and cannot resist active attacks. By improving the Tseng's protocol, the authors propose a new dynamic authenticated group key agreement protocol. Due to using ID-based public key, the expense of building and managing public key infrastructure is decreased, and the protocol supports mutual authentication between nodes. The analysis results show that this protocol can satisfy the security rules of group key, meanwhile, reduce the computation and communication cost of the ordinary nodes.

Abstract:In communication system, frequency warp is often caused by the coherent detection or the synchronous demodulation. Because in one frame the sample time of each code is different from that of other codes, the phase error of the demodulated code and the decoding error would become larger and larger as time goes on. A carrier synchronization method, in which the Cordic algorithm and the efficacious LDPC decoding performance are adopted, is presented to solve the frequency warp. According to this algorithm, the frequency warp is figured out by using the Cordic algorithm, and then the phase error caused by the frequency warp in each receiving code is modified by using the Cordic algorithm again. Finally, the modified code is delivered to the decoder based on the LDPC decoding algorithm. Simulation results show that by using this method not only the multiplicative manipulation is substituted for the shift manipulation, but also the algorithm's performance is approaching to the precise synchronous performance.

Abstract:In this paper, a Near Space Ka frequency village system covering Channel Model is built. Firstly, Near Space Channel's geometry is discussed, according to different elevations, the communication coverage area is divided into high elevation area, middle elevation area and low elevation area. Secondly, the five factors those have an impact on channel characteristics, i.e. atmospheric absorption attenuation, troposphere flashing attenuation, cloud attenuation, raining attenuation and multipath effects caused by the ground body reflection, are analyzed. The summary is given that the influence of the raining attenuation and that of the multipath effects on Near Space Ka band communication channel are much larger than those of the other three factors. Finally, the impact of ground reflector and that of raining attenuation on the channel in different elevation cases are analyzed. And according to Ka band geostationary satellite communication channel signal's probability distribution of parameters in various weather conditions, Near Space Ka frequency village system covering Channel Model is simulated, and the BER performance simulation curves of different elevation areas are given. The model in this paper is of guiding significance in exploration and research of Near Space communication.

Abstract:For the fixed orthonormal basis, the design of the determinate measurement matrix is investigated by using the incoherence criterion between the measurement matrix and the sparse basis. The smaller the coherence between the measurement matrix and the sparse basis is, the less the required measurement number in the process of compressed sampling is, the more information in the original signal will be contained, and the higher the probability of restructure is. According to the definition of coherence between the measurement matrix and the sparse basis, the minimax method of satisfying optimal incoherence is constructed for the fixed known orthonormal basis, furthermore, the measurement matrix that is most incoherent with the orthonormal basis can be found. Finally, to verify the effectiveness of the method mentioned in this paper, the comparison, between a numerical simulation example of taking the fixed orthonormal basis as a discrete cosine basis and the coherence corresponding to the common measurement matrices, is made.

Abstract:This paper, considering Demsper rule's disadvantage in aggregating the expertise of high conflict, presents the evidence conflict degree based on conflict coefficient and Jousselme distance. The objective expert weight is computed by using the evidence conflict degree. Then Demsper rule is used to aggregate the modified expertise. Finally, a new probability degree formula is established and the belief interval method based on probability degree is used for decision-making. The numerical examples illustrate that the proposed method is more efficient in combining the conflict expertise than several improved DS methods and compared with the maximum belief function method and plausibility function method, the belief interval method proposed is more scientific.

Abstract:The solid-state reaction method (sintering process) is used for preparing the synthesis of Ca-dopedY1-xCaxBa2Cu3O7-δpowders and bulk superconductors. The influence of Ca-doping on microstructure and trapped magnetic flux of Y1-xCaxBa2Cu3O7-δis investigated. It is found that the club-shaped grains are formed for the Y1-xCaxBa2Cu3O7-δ superconductor with Ca quantity x=0.2. The grain size is about 15um and all the grains are well linked. The grain boundary is especially clear and the maximum trapped magnetic field changes slowly while the pulsed magnetic field changes. So the reasonable Ca doping content is around x=0.2.