The use of radar to detect micro-Doppler frequency peculiar to the ballistic missile is a new method for target detection,and the selection of the scattering points on the target body is one of the key factors in the extraction of micro-Doppler characteristic parameters.Firstly,the motion model of the warhead of the ballistic missile is established and the extraction method for the micro-Doppler characteristic parameter of the warhead target based on the time-frequency analytical method is given.Then,the scattering points on the target body are classified into four types according to the different positions of them.By simulating the extraction of micro-Doppler characteristic parameters,the properties of the characteristic parameters changing with the scattering point are analyzed.The simulation results show that:1) The fretting characteristic parameters of the missile can be effectively extracted by selecting the scattering points from the top,the edge of the bottom and the conical surfaces of the missile cone,with the total number less than 9;and 2) With the increase of the number of the scattering points,the difficulty for extracting the fretting characteristic parameters is correspondingly increased,to the extent that it is impossible to extract the fretting characteristic parameters.

In order to solve the problems of the least-square method in satellite fault detection,a Weighted Least-Square (WLS) algorithm is proposed for satellite fault detection and recognition.The algorithm uses the diagonal-line factor in the covariance matrix of the measurement equation as the weighting factor.Then the satellite-fault-detection algorithm based on the WLS method is obtained.The test statistic is established by using the quadratic sum of the pseudo-range residual errors of each satellite.The detection threshold is obtained from the false alarm rate of the fault detection and the probability density function.The calculated quadratic sum of the pseudo-range residual error is compared with the detection threshold,and then the fault detection and isolation is realized.Analysis is made to the performance of the two algorithms according to the measured data.The results show that the WLS RAIM algorithm is superior to the least-square RAIM algorithm on the fault detection sensitivity and fault recognition performance.

Due to the limitation of sensing ability,the fuzzy membership of the remote AUV autonomous decision-making attribute is not clear,thus the traditional fuzzy Petri net decision-making method can not implement knowledge representation and reasoning.This paper expands the fuzzy set of fuzzy Petri nets,puts forward the concept of interval-valued intuitionistic fuzzy Petri net,and redesigns the reasoning methods and decision-making process.Based on the interval-valued intuitionistic fuzzy Petri net,the remote AUV action decision-making model is established,and the remote AUV autonomous action decision-making is realized by using an example.The decision-making process is eloquent,rapid and clear,and the result of the decision-making proves the validity of the method.This method gives a new thought to multi-attribute decision-making.

A fuzzy backstepping adaptive controller with a command filter was designed for a fixed-wing aircraft to overcome the problems of the restricted state and actuator′s physical characteristics during the flight control process.First,the MIMO strict feedback system with error terms was developed.Secondly,a fuzzy system was developed to approach the error terms of the subsystem online,and the virtual control law was designed for each subsystem based on Backstepping method.Thirdly,considering the state constraints and the physical characteristics of actuators (including the constraints of amplitude and rate),a command filter with constraints on amplitude,rate and bandwidth was introduced into the designed virtual control law to compensate for the filter error term.Finally,Lyapunov stability theorem was used to prove that the closed-loop system is guaranteed to be bounded,and the tracking error converges exponentially to a small neighborhood around zero.The simulation results show that the designed controller has strong stability and robustness.

In view of the uncertainty about the quad-rotor aerial vehicle system,a new control method is proposed by combining sliding mode control with the adaptive neural network.Considering the existing uncertainties in the actual system,such as inaccurate modeling and unknown parameters,and based on the sliding mode control,we constructed a RBF neural network to on-line approach the unknown functions of the system model,and designed an adaptive law to on-line estimate the weights of the neural network and the unknown parameters using the Lyapunov method.The stability of the system was verified by Lyapunov theorem.The simulation results show that:compared with the adaptive PID controller of the RBF neural network,this controller has a shorter settling time,less overshoot and better resistance to disturbances,and it also has a stronger robustness when the model parameters are changed.

To improve the filtering precision under complex noise condition,a new Square-root Cubature Cost-Reference Particle Filter (SCCRPF) is proposed based on the Square-root Cubature Kalman Filter (SCKF) and the Cost-Reference Particle Filter (CRPF).The proposed filter updates the prior distribution function with the latest measured information and SCKF,and thereby generates the importance density function for CRPF.The new filter not only reserves the precision advantage of SCKF in filtering nonlinear systems,but also possesses the filtering precision of CRPF for dealing with systems with an unknown noise assumption.Simulation results show that:the filtering precision of SCCRPF is higher than that of Square-root Cubature Particle Filter (SCPF) for a system with unknown noise assumption,and is higher than that of CRPF for a system with known noise assumption.

In order to solve the problems of dynamic path planning for Unmanned Aerial Vehicles (UAVs) confronted with sudden threats,a dynamic UAV path-planning method is proposed based on multi-strategy SSO (Social Spider Optimization) and the improved A* algorithm.The UAV path planning is divided into two stages: static path planning and real-time evasion under sudden threat.At the stage of static path planning,multi-strategy SSO optimization algorithm is used to solve the polar-coordinate path-planning model,and the mechanisms of perfect elastic collision and adaptive skipping are introduced,which can improve the feasibility of the path-planning results while satisfying the restraints of flight performance.At the stage of real-time evasion under unexpected threat,the improved A* algorithm is used for path planning in local regions for a second time.Through expanding the number of neighborhood for A* algorithm and introducing the minimum “bent” estimation cost function,a smoother optimal path can be obtained while satisfying the real-time requirements.The simulation results show that the proposed method can provide more satisfactory dynamic path-planning for UAVs.

Considering the characteristics of the sonobuoy and the demand for the checking search,we put forward a method for searching grid sonobuoy arrays based on the meta-grid.First,the meta-grid is constructed.Then the size of the meta-grid and the needed number of sonobuoys are studied in detail by building models.And then the number of the meta-grid,the number of sonobuoys and the searching area of the grid sonobuoy array are analyzed.In the end,the searching efficiency of the grid sonobuoy array is evaluated by simulation,and an analysis is made to the simulation results and conclusions useful for military operations are obtained.

To solve the problem of dynamic data association in the multi-target tracking system of heterogeneous sensors,a dynamic data association algorithm for heterogeneous sensors is proposed based on KL distance.This method extends the static multi-dimensional assignment to dynamic tracking.The KL distance between the probability density function of the estimated position and the probability density function of the predicted position of the target track is taken as the association cost function,by merging the measurement set with the track set.Then,it is substituted into the multi-dimensional assignment model to realize the dynamic correlation between measurements and tracks.Simulation results show that the proposed cost function can reflect the association probability between measurements and tracks more accurately and can track multiple targets quickly and steadily.

Color and shape are the two main features of an image target.In order to improve tracking accuracy and robustness,a new multi-feature fusion tracking algorithm fusing color and shape features of the image target is put forward.The histogram model of space color probability based on HSV space,and the Hu invariant moment model after the gray-scale transformation are adopted respectively for real-time target tracking.And then an adaptive weighted method is adopted to confirm the final tracking location of the image target.Two experiments demonstrate that the proposed method has very strong robustness under the circumstances of complex background interference and to the change of color,scale and brightness.At the same time,the algorithm improves the tracking results and the effective rate of tracking.

Considering the complex characteristics of quad-rotor aerial vehicles,such as multiple variables,strong coupling and the constraints,we proposed a controlling method based on explicit model prediction. According to the dynamic characteristics of the quad-rotor flight system,a nine-state space model was built,which was decoupled into two subsystems.Then,the explicit optimal controlling law of the quad-rotor flight system is calculated offline by multi-parameter quadratic programming,and the controlled quantity corresponding to the current state was searched online. Numerical simulation and experiment results show that the proposed method has the advantages of short adjusting time,small overshoot and certain anti-disturbance ability,as well as meeting the constraint requirements,and the stability control of the attitude is successfully achieved.

The historical development of multi-channel Synthetic Aperture Radar (SAR) system is presented from three aspects of InSAR,SAR-GMTI and dual-/multi-channel cancellation technique,and theresearch progress of Electronic Counter-Countermeasure (ECCM) is summarized with focus on the status quo of multi-channel SAR ECM technique.With regard to multi-channel SAR ECCM,an introduction is made from two aspects: antenna/structure and signal waveform,and the characteristics of dual-/multi-channel cancellation technique are analyzed.As to multi-channel SAR ECM,the prospect of ECM is analyzed emphatically,and emphases are laid on the complexity of modulation,the coherency of interference,the multi-station distributed countermeasure and the multi-channel SAR ECCM.

Head-Up Display (HUD) onboard civil aircrafts is a crucial safety system.Because of its high complexity and other airborne systems combined with it,the traditional system-safety-assessment method has difficulty in meeting the requirements of a quantitative safety analysis.Therefore,it′s necessary to develop a Model-Based Safety-Assessment (MBSA) method.On the basis of clearly defining the principles of the probability model check and the high-level system-modeling specifications,we studied the method for hierarchical modeling of the probability model of the HUD system,built the probability model of the HUD system,described the quantitative safety properties of the system,and carried out automatic probability model checks.The conclusion of the quantitative safety analysis was obtained,which can improve the efficiency of the safety analysis and the accuracy of the calculating results.

Too many Optical True Time Delayers (OTTDs) are needed when optically phased array radar scans in wideband and wide-angle modes.To solve the problem,a beam-forming method based on compressed sensing is proposed for the optically phased array radar with sparse array.Firstly,the factors affecting main-lobe deviation are analyzed in detail by formula derivation.Secondly,a configuration of the sparse antenna array is presented,on the basis of which,the pattern of the optically phased array is restored based on the compressed-sensing theory.Using this method,a quite small number of OTTDs are required for wideband and wide-angle scanning.Finally,this method is validated by the simulation results.

The deck motion has been one of the key factors influencing the implementation of sea fight missions of carrier-based aircrafts.To decrease the interference of the deck motion during the landing process of the UAVs,we designed a deck motion compensator based on optimal preview control,which was used to form a deck motion tracking control system with the Kalman-filtering-based deck motion predictor.The system can effectively avoid the phase delay of the traditional deck compensation system by using the deck motion prediction information and the features of preview control operation.Finally,the small nonlinear fixed-wing UAV model was used for simulation.The simulation results show that the system can effectively track the deck motion,and thus improve the success rate of UAV landing.

A great number of flight parameters are recorded by the Quick Access Recorder (QAR) equipped on civil aircrafts.QAR data is an important criterion for flight safety assessment.Aiming at large-sample and high-dimension features of flight data from QAR,this paper proposes an effective feature extraction algorithm,Deep Belief Network (DBN) algorithm.The DBN algorithm can adaptively extract the features of flight data independent of data-processing technologies and expert experiences.Simulations of different types of flight data sets are carried out.The simulation results show that,compared with the PCA algorithm,the accuracy of classification and identification of features extracted by DBN model is higher.

In order to improve the accuracy of the structural dynamic model of the inner gimbal of the electro-optical stabilized sighting system, and to improve the efficiency of the simulation analysis, a structural dynamic model updating method based on the multi-population genetic annealing algorithm was proposed. Taking the inner gimbal of an electro-optical stabilized sighting system as the object of study, we built the Finite Element Model (FEM) by using the dynamic substructure technique. Based on the modal test results, the FEM was updated by using the multi-population genetic annealing algorithm and the correlation analysis to obtain the six-dimensional stiffness value of the inner gimbal bearing in global optimization. An additional experiment was carried out to test the reliability of the updated FEM. The experiment result showed that FEM and the test result were well-matched, the correlation between the modals was over 0. 8, the frequency error was below 9. 05%, and the calculating efficiency was increased by 95%. Thus an effective and feasible model updating method was obtained, which is an important reference to the structure design of the inner gimbal of the electro-optical stabilized sighting system.

The attacking UAVs have slow response speed in the battlefield and have difficulty to support the tactical unit.To solve the problem,a small attacking quad-rotor UAV system is proposed.The system can be carried by one soldier,which is adaptive to a variety of operational conditions owing to the high stability of the four rotors.Combined with image processing technologies,the system can help soldiers analyze the battlefield situations,quickly identify enemy units and finally launch attacks.The system can meet the operational requirements of army soldiers under the modern operational conditions,and provide more possible operational methods for army′s tactical units.

The helicopter is a crucial tool of marine search,and its searching ability needs to be improved with the increase of national marine trade and military activities. The rationality of the search route is the key to an efficient search and a high success rate. Under the premise of the access to the target location,this paper provides the route-planning methods under different scenarios. At first,two kinds of electronic route-planning methods are given under the scenario of using handheld device. Then,the route-planning method for visual search is analyzed emphatically,with the range of visual observation,the estimation of survival time,the limits on flight height,the limits on flight speed,the calculation of marine search width,the calculation of the starting point of searching,and the selecting principle and parameter settings of the three common routes. At last,the flow chart of the whole algorithm is presented with the simulation analysis.

When Synthetic Aperture Radar (SAR) works in the squinted mode in the case of a large grazing angle,the Range Walk changes greatly with the slant range.The traditional SPECAN imaging algorithm corrects the Range Walk only referring to the centered slant range,there are residual Range Walks on the range edge of the swath,which finally leads to target defocus.In order to solve this problem,a modified SPECAN imaging algorithm based on Chirp Scaling Principle is proposed.Firstly,it is multiplied by Chirp Scaling factor in the two-dimension time domain to eliminate the range variations of the Range Walk.Then,it employs the traditional SPECAN imaging algorithm to accomplish the two-dimension focus of the image.Numeric simulation results confirm the validity of the proposed algorithm.

Based on the vulnerability mechanism of wireless receivers,this paper proposes a method to construct a complex electromagnetic environment based on the vulnerability mechanism of the receivers,which solves the problem that a great amount of electromagnetic environment simulation equipments are needed for the combating unit with large frequency span. A multi-excitation,multi-response sleeve barrel evaluation model is built,which is based on signal channel occupancy,spectral overlap degree,background signal intensity and other factors in electronic information system. It solves the problem of the objectivity and figurativeness evaluation of the tested object,and supplies a useful reference for complicated electromagnetic environment adaptability identification.

The rugged LCD used in high-temperature environments is prone to present Mura,which severely worsens display quality.To solve the problem,the paper proposes a method based on experiments and finite-element simulation to deeply analyze the high-temperature display characteristics of the rugged LCD.Thermodynamic simulations of common LCDs and rugged LCDs are firstly performed using the finite-element simulation software,and then the thickness changes of the LC layer are analyzed.Thermodynamic experiments are finally performed.The practical and simulation results show that:1) The liquid crystal layer has obvious change at the Mura position,and the Mura becomes severe with the change of the layer thickness;and 2) The rugged LCDs have higher possibility of Mura at high temperature,and Mura possibilities of LCDs from different manufacturers are different.To minimize the problem of Mura,more work should be done to screen the LCDs.