Abstract:A sensor’s analytic reconfiguration control method is presented based on unknown input observer (UIO) for aero engine distributed control system（DCS） with control delay and unknown disturbance. An unknown input observer is in correspondence with a sensor whose input is a controlling quantity and information for other sensors, and output is a reconfiguration signal corresponded to the sensor in troubling. The existing sufficient condition of UIO, which is described by linear matrix inequalities, is deduced for small-divergence state space model of aero engine. When the gain of the controller is given, the parameter matrix of the UIO can be solved, and all the UIOs can be designed by iteration. The numerical simulation result shows that when the sensor is out of order, the UIO’s output may go instead of fault sensor’s signal as a state feedback value to control the engine model, and the system has a good dynamic response under different disturbance. This proves that the observer can decouple the external disturbance and not be influenced by the fault sensor and effectively reconstruct the fault sensor signal.

Abstract:This paper analyzes an influence of speed of the supersonic speed stealth aircraft on dynamic RCS series and radar detection performance. First of all, the paper sets flight tracks in accordance with aerodynamics, and obtains the real-time angles of radar sight with random jitter. Afterwards, the paper analyzes an influence of speed on dynamic RCS series by utilizing physical optics and method of equivalent currents. Finally, based on the stealth aircraft’s RCS fluctuating data, the paper deduces the computational formula of detection probability of fluctuating targets, and researches on an influence of speed on radar detection performance. The results show that the greater the speed is, the lower is the probability, and the more severe is the fluctuating detection. This research can provide a support for the detection of supersonic speed stealth target.

Abstract:Aimed at problem that unmanned combat air vehicle exists in autonomous air combat tactical decision making, this paper presents an approach of case-based reasoning (CBR) and rule-based reasoning (RBR) and a method for describing autonomous air combat tactical decision making cases based on frame structure. The research shows that the improved nearest neighbor approach can improve the effectiveness and accuracy of case-based reasoning by introducing the calculation method of structural similarity and the theory of cloud model. Finally, the result of simulation shows that any appropriate solution can be selected from the case library.

Abstract:DoDAF2.0 architecture framework is researched to meet operational architecture problem study demands. Data center concepts of DM2(DoDAF Meta-model), application of View Points, functions of Views and the relation of them are analyzed. A data centric development approach and practical process is presented based on theses. And a multi-aircraft cooperative detection system is developed under Rational Rhapsody7.6 to demonstrate the proposed methods. Finally the validation method of architecture and further discussion is given.

Abstract:On the basis of the detailed analysis of the basic detection evaluation parameters, point target evaluation parameters and area target evaluation parameters, this paper effectively resolves the limitations of the day and night backgrounds by the optical spectral segment selecting according to the optical properties of the low speed target in the near space, and designs a near space low speed target detectability evaluation system and optimization scheme based on optical method. Moreover, in consideration of the spectral constraint condition, the position constraint condition, the detection ability and the evaluation parameters of the optical detector in detailed through different equivalent effect curve surfaces of single and multiple detectors by numerical, the simulation result indicates that when the target is inside the equivalent curve surface, the detecting effect is better than that of the expectation and can meet the needs of the detection requirements, on the contrary, the detection effect is worse than that of the expectation, and cannot meet the needs of the detection requirements, unless the detection scheme is modified. The results show that the near space low target detectable evaluation system is effective based on the optical method.

Abstract:In order to estimate the impact point for ballistic missile rapidly, an impact point estimation method is proposed based on orbital elements handover. There are two kinds of orbital elements. One is computed by ground based multi-function phased array radar and the other one comes from warning center provided by long-range early warning phased array radar combined for precise orbit determination. The precise impact point can be offered if the impact point error accuracy is satisfied. The simulation results show that compared with traditional method, the proposed method can shorten the period of the predictable time by 40%.

Abstract:Aimed at the problems that radar is a normal way used in tracking target at the battlefield, when hostile force uses active suppressing interference, the target trace is lost, and the radar fails to track target continuously, this paper builds a radar tracking system based on cooperative detection of airborne multi-sensor resource in interference to improve tracking property for target. Firstly, the paper predicts the radar lost information by Kalmansmoothing. When tracking precision can’t make the desired value satisfied, the paper estimates the lost data and continues Kalmansmoothing estimation by applying the method of SVMR, thus achieving to track the target continuously, and the precision is higher. The simulation proves that the system can solve the lost problem of target trace under condition of active suppressing interference, thus enhancing radar tracking property for target.

Abstract:In order to solve ESM-radar track correlation problem under condition of the influence on the maneuvering target close and cross, this paper presents a track correlation algorithm based on the improved Fuzzy comprehensive evaluation. In consideration of distance, angle, speed, phase difference and time difference information of the ESM sensor and radar in the cooperative passive location, the algorithm enriches the fuzzy factor set, gives out a dynamic calculation method of membership degree and weight in fuzzy comprehensive evaluation, and correspondingly improves the evaluation set and the evaluation criterion. The simulation results show that when the target is at the distance of 200m, the traditional multi-factor fuzzy integration judgment algorithm’s correlation accuracy is 55.2%, and this paper’s algorithm’s correlation accuracy is 74.0%. Under condition of increasing the target distance and the radar detection error, this algorithm’s correlation accuracy is always higher than that of the traditional multi-factor fuzzy integration judgment algorithm.

Abstract:Aimed on the problem that the robustness of single feature tracking algorithm is poor in visual target tracking, this paper proposes an object tracking algorithm based on multi-feature fusion using game theory. Under condition of the mean shift tracking framework, the paper takes color feature and motion feature as two players. Through looking for the Nash equilibrium of their game, the paper makes the contribution of different features in the tracking result the best balance, and furthermore a higher advantage of multi-feature fusion. The experimental results show that this algorithm has the stronger robustness of tracking under object strenuous motion, occlusion and background motion interference. By means of multi-feature fusion based on game theory, the paper presents a new algorithm on the basis of the traditional mean shift algorithm, and the algorithm is good in performance on tracking.

Abstract:Aimed at the problem that because the result zone algorithm is in search of space by adopting the method of traversing all attitude angles, the initialization time is comparative long,an improved planar ambiguity searching method is proposed based on the combination of narrow lanes. First, based on the relationship of satellite space geometry to restrain the narrow lane ambiguity scale between reference star and two main stars, all the candidate attitude angles can be obtained by using the relationship between the attitude angle and the narrow ambiguity, thus obtaining the searching range in a way neither traversing nor missing the correct candidate. And then, each corresponding narrow-lane ambiguity float solution is derived from result zone planar searching model. and the narrow-lane ambiguity is fixed by using ambiguity integer characteristics method, baseline length constraint method and least square sum of baseline residual. The experiment results show that the new method can effectively reduce the initialization time from 153 s to 76 s and the attitude accuracy invreases nearly by 15% comparing with the original algorithm.

Abstract:Aimed at problems that there is a threat of emitter on timeliness, and complexity and imprecision exist in assessment process, a novel algorithm in assessment based on IFS-BN is proposed combined with Intuitionistic Fuzzy Sets (IFS) and Bayesian Network (BN). The IFS-BN algorithm fully describes determinacy, non-determinacy and hesitancy degree more adequately through the node information in Bayesian Network. On the basis of this, the algorithm substitutes priori probability calculated by Intuitional Fuzzy Sets into Bayesian Network model to obtain posteriori probability. Then, sequences of the threat level are acquired by posteriori probability. Meanwhile, corresponding evaluating index system of emitter threat assessment is established. The simulation shows that the algorithm is feasible and effective, and the results are much more objective and reasonable compared with the classical method of emitter threat assessment based on Bayesian Network.

Abstract:In view of the suppression of transmitting deceptive jamming in radar countermeasure, this paper proposes a discrimination and suppression arithmetic based on time-frequency analysis and fisher clustering. Through STFT conversion, the paper analyzes and extracts the time-frequency characteristic of mixed signals by the arithmetic, and then distinguishes the jamming via fisher clustering. Finally, the arithmetic restrains the false targets through time-frequency filtering. The simulation results show that the arithmetic can restrain the deception jamming with frequency shift effectively. When the jamming and the echo are in different unites, the jamming can be filtered directly in any jam-to-signal ratio (JSR), and the interference can be suppressed whose JSR is under 25dB.

Abstract:In order to satisfy the practical requirement that multiple GNSS spoofing signals need high captured performances integrally, a power control strategy based on the cross-correlation interference of multiple signals is proposed. With an analysis on noise floor influenced by multiple spoofing power, the acquisition of spoofing signal is discussed. Utilizing the rise of noise floor and spoofing relative acquisition probabilities, a objective function is built, and the optimized solutions is obtained based on genetic algorithm. Simulations show that multiple spoofing acquisition performance is superior to the authentic according to the proposed strategy, while the noise floor rises no more than 10dBW and the spoofing power is uncorrelated.

Abstract:Capacity is an important indicator in communication systems performance, the capacity of Orthogonal Frequency Division Multiplexing/Offset Quadrature Amplitude Modulation(OFDM/OQAM) system over multipath Rayleigh-Fading channels is thoroughly investigated. Through analysing the probability density function(PDF) of Rayleigh channels model and deducing the alliance of probability density function in two random relevance Rayleigh channels, we get the mathematical expression about the mean and variance OFDM/OQAM system capacity in multipath Rayleigh-Fading channels, which the function of the parameter is related to the number of the subcarriers of an OFDM/OQAM system, the signal to noise ratio(SNR) and the number of multipath. Simulating the system, we analyse the influence of the mean and variance OFDM/OQAM system about the parameter. The result shows that the systems mean is proportional to SNR and inverse proportional to the number of the subcarriers; the systems variance is defined by SNR and the number of multipath.

Abstract:Aimed at sorting frequency-hopping networks for under-determined multi-hopping signals, this paper utilizes the temporal sparsity of frequency hopping signals and adopted time-frequency ratio of the original source in hopping signals to estimate hybrid matrix. In calculating the time-frequency matrix, this paper uses the fast overall K average cluster through combination of subspace projection and relative power offset to realize the FH sorting for under-determined condition. Meanwhile, in order to improve the performance of sorting under low SNR condition, the adaptive SNR time-frequency supporting point method is adopted into searching the original single source point. The algorithm is verified by theoretical analysis and simulation.

Abstract:Based on the hydraulic servo testing machine and the split Hopkinson pressure bar (SHPB) with a diameter of 100 mm, the dynamic / static experiment compression tests of red-sandstone with different saturated degree of water are tested, the mechanical properties of the rock is studied, and the experimental conclusion from the perspective is analyzed. The conclusion is that there is a critical saturated degree Sl for the impact on rock strength. when the saturated degree is less than Sl , the intensity linearly decreases with the increase of saturated degree. when the saturated degree is larger than Sl, the change range of rock strength is very small along with the rising of the satisfied degree. The minimal peak strain appears at the saturated degree of 0.42 and the peak strain under the condition of dynamic test is more sensitive to the saturated degree. The Peak modulus linearly decreases with the increase of saturated degree. From a judgment upon the influence of the saturated degree on the peak modulus from the Microcosmic view, three key parameters should be seized, i.e. loading ability of mineral grains and cement between them, coordinate ability to deformation of them and degree of pore development. Along with the rising of the saturated degree of water, the strain rate effect of rock mechanics properties have become more and more obvious. Among them, the saturated degree of water has the greatest influence on the strain rate effect of rock strength and the smallest effect on the strain rate effect of rock modulus.

Abstract:This paper researches on sampled-data consensus of first-order delayed multi-agent systems with weighted average predication. First, the paper obtains a consensus protocol based on sampled-data by using the delay decomposition technique, and simultaneously obtains the necessary and sufficient conditions about the sampling period guaranteeing the achievement of consensus by using the stability theory of linear systems and the algebra graph theory. Last, the paper demonstrates the effectiveness of the theoretical results by simulation, obtains the sampling period, and simulates and verifies two kinds of conditions. This provides a feasible solution for the consistency problem of the sampled data control of a first-order multi-agent system.