
Considering the issues existed in the research results of current combat intention identification and predictionsuch as too few typestoo coarse granularityand lack of targets and objective of attack in the selection of combat intentionsas well as the demand for intention recognition in the future equipment development and mosaic war environmentthis paper analyzes the formation process of combat intention and the relationship between combat intention and the behaviorand introduces the explicit and implicit attributes of combat intention.Combined with mosaic operational requirements and the reality of multi-domain joint operationsthe combat intention is decomposed by typesprocessesstates and rolesand a three-level granularity model of combat intention is establishedwhich realizes the multi-levelmulti-attribute and multi-granularity detailed modeling of combat intentionand provides reference for the identification and prediction of combat intention.
In view of the shortcomings of traditional Ant Colony Optimization (ACO) algorithm in path planning of Unmanned Aerial Vehicle (UAV)such as slow convergence speed and easy to fall into local optimal solutionan Improved Adaptive Ant Colony Optimization (IAACO) algorithm is proposed.Firstlyin order to make ants move in the direction of the target point with greater probability and improve the search efficiency of the pathan angle guidance factor is introduced into the transfer probability of ACO.Thenheuristic information adaptive adjustment factor is introduced to balance the convergence and global search ability of the algorithm.Finallyby defining length index function and angle index functionthe objective function of route optimization is further established,and the global optimization of UAV route planning is realized.Experimental results show that the improved algorithm converges fasterand the generated track is smoother and shorter.
In order to accurately estimate the target number of Probability Hypothesis Density (PHD) filtersa cardinality compensation method based on Information-weighted Consensus Filter (ICF) and data clustering is proposedand ICF is used for information fusion.In a dense clutter environmentwhen the noise and clutter in the measurement are hightracking loss will occurand the performance of target number estimation will be degraded.For this reasona cardinality compensation process is added to the PHD filterbased on an information fusion stepthe estimated cardinality obtained from the PHD filter and the measured cardinality obtained through data clustering are used to obtain the final target number estimation.In order to verify the performance of the proposed methodthe simulation is carried out and it is demonstrated that the tracking performance of multiple targets is improved.
Aiming at the problems of the traditional fractal detection algorithm in Fractional Fourier Transform (FRFT) domain in sea cluttersuch as difficulty in determining the optimal order and unstable performancean improved fast detection algorithm of small targets on sea surface based on fractal transform domain is proposed.The new algorithm uses the fast estimation algorithm to quickly determine the optimal order of the target echo in FRFT transformand after FRFT transformthe energy is accumulated and the signal-to-clutter ratio of the echo is improved.On this basisthe Improved Multifractal Detrended Fluctuation Analysis (IMFDFA) algorithm is used to study the multifractal of sea clutter.The target detection is carried out on the measured data of IPIX radar.The experimental results show that the optimal order optimization algorithm proposed in the new algorithm has stable performance.Compared with the traditional fractal algorithmthe performance of the IMFDFA algorithm is obviously improved and more stablewhich is beneficial to the application of the algorithm in detecting small targets on sea surface to a certain extent.
Aiming at the problem of how the attacking missile strikes the ground target effectivelywhich defends the attacking missile by launching defensive missilea three-body game engagement kinematics model is establishedan objective function integrating miss distance and required acceleration is constructed and a differential game guidance law considering first-order kinetics autopilot is proposed.On the premise of three-point guidance and interception of defense missilethe guidance strategies of proportional guidance and differential game guidance of attack missile are simulated and verified respectively.Finallythe effectiveness of the proposed method is proved by analyzing acceleration constraints and terminal conditions.
UAV formation topology optimization is of great significance for improving the coordination of UAV cluster task execution and communication transmission efficiency.Firstlythe index of residual energy imbalance of UAV formation is proposed.Based on the length of formation communication chainthe influence factors of network delay and residual energy imbalance are brought into the generation system of UAV formation information interaction topologyand multi-objectives are considered comprehensively to optimize the UAV cluster information interaction topology.By constructing a satisfaction deviation membership functionthe goal programming model is established to realize the synthesis of multiple goals.At the same timethe multi-tree structure is used for classification in topology generationand the artificial bee colony algorithm is improved to solve the modelwhich can support the cooperation of large-scale UAVs.Finallythe formation composed of 16 UAVs is simulated and analyzedand the rationality of the model and the effectiveness of the algorithm are verified.
Compared with the conventional pulse Doppler radar signal processingSpace-Time Adaptive Processing (STAP) expands the signal processing dimensionso that the clutter and the target can be distinguished in the joint space-time domain.Based on sparse representation theory and the sparsity of clutter spectrumSparse Recovery (SR)-based STAP realizes clutter suppression under the condition of a small number of training range cells.Aiming at the performance degradation of SR-STAP methods with unknown yaw anglea nonlinear regression-based clutter reconstruction STAP method is proposed.Firstlybased on SR clutter spectrumoutlier degree is used as the convergence objective to iteratively eliminate the scatter points deviating from the ridgeand the coordinate weighted nonlinear regression is performed to realize accurate estimation of the parameters of the clutter ridge model.Thenbased on the results of the first screeningthe clutter spectrum is estimated accurately by the nonlinear regression method again.Finallythe clutter reconstruction and suppression are completed based on the above estimation results.The simulation verifies the effectiveness of the proposed methodand compared with the existing STAP methodsit achieves better space-time frequency response and SINR losseffectively improving the performance of clutter suppression and moving target detection.
According to the performance characteristics of reentry cross-medium unmanned aerial vehicle this paper puts forward its operational application scenario and application assumptionand models and analyzes its battlefield superiority and operational effectiveness from the following aspectssuch as the penetration efficiency and battlefield survivability of the reentry cross-medium unmanned aerial vehicleand its impact on detection windowinterception and trackingand combat resources.
Aiming at the space-time cooperative problem of UAV swarm attacking moving targets on the sea surfacea designated time cooperative control method is proposed.The relative motion between each UAV and its neighbors is transformed into an optimal tracker with a specified end time.Different quadratic cost functions are designed for the two control objectives with the specified time parametersnamelystrike configuration generation and strike configuration maintenance.By solving the control law by Runge Kutta methodthe UAV cluster can be driven to accurately generate the strike configuration at the specified timerealize simultaneous strikeand maintain the strike configuration in the subsequent specified time periodso as to realize continuous strike.The simulation results show that the UAV cluster can generate and keep the desired formation configuration at the specified momentand track the moving target.
Synthetic Aperture Radar (SAR) is a coherent imaging system.The images generated from SAR are often polluted by speckle noisewhich results in low accuracy in subsequent segmentation and recognition of SAR images.Aming at the problem of image pollutiona SAR image denoising network model Re-GAN is designedwhich combines Generative Adversarial Network (GAN) with the Residual Network (ResNet).The residual block of ResNet is added into the generator of GAN to enhance the ability of SAR image denoising.The combined loss function in the model can better preserve image details during noise reduction.In MATAR data setRe-GAN is compared with BM3D and wavelet denoising algorithm respectively.The experimental results show that Re-GAN has good performance in both visual effect and quantitative analysis.
In the complex electromagnetic environmentthe recognition rate of radar jamming signal is low under the condition of low Jamming Noise Ratio(JNR)and it is difficult to obtain a large number of jamming samples for training.To solve the problema radar jamming perception method based on Attention mechanismtransfer learning and residual neural network is proposed.The model takes the time-frequency domain data of interference and echo as inputautomatically extracts features and makes type judgment.The experimental results show that the model realizes the effective perceptual recognition of radar jamming under the condition of low JNR and small-sample training.The Attention mechanism and transfer learning can effectively improve the accuracy of perceptual recognition.The recognition performance is more robust and accurate than that of the traditional machine learning model and the unmodified neural network model.
In order to solve the problem of blind estimation of frequency hopping signal parameters with fixed frequency interferencea removal algorithm based on time-frequency energy value cancellation is proposedand the blind parameter estimation of frequency hopping signals is realized by least square method.Firstlythe K-means algorithm is used to select an adaptive threshold for the clustering of the energy cancellation valueand the noise and fixed-frequency interference are removed synchronously.Secondlythe maximum energy of the frequency axis at each moment of the reconstructed time-frequency matrix is extracted to obtain the envelope diagram of periodic oscillation.Finallythe least square method is used to linearly fit each extremum of the envelope diagram to realize the blind estimation of the frequency hopping signal parameters.Simulation results show that:Compared with similar algorithmsthis algorithm effectively removes fixed-frequency interferenceachieves high-precision estimation of frequency hopping parameters under the condition of lower SNRand maintains the relative accuracy of estimated parameters at a high level.
In order to achieve compund guidance functionssuch as autonomous guidancetarget positioning tracking and searchingetc.a design scheme of a small optical lens is proposedwhich can realize the integration of infrared and laser dual-spectrum and common aperture.The transmission optical system is adoptedand a wedge angle splitter is arranged in the optical pathwhich not only realizes dual-spectrum beam splittingbut also effectively corrects the system aberration caused by the 45° inclined flat plate.As a resultthe average Modulation Transfer Function (MTF) of the infrared channel is better than 0.45(30 lp/mm)and the diameter of diffusion spot in ±1.5° linear area of laser channel is 4.88~5.03 mmand the energy distribution is uniformwhich meets the requirements of the index.Finallythe high-precision optical centering adjustment and three-coordinate precise measurement are used to complete the assembly and adjustment of the lens.The average MTF of the full field of view of the infrared channel is better than 0.38the shape of the dispersion spot in the laser channel is symmetricalthe energy is evenly distributed in the linear regionand the lens effect is good.
Aiming at the flexibility requirement of resource organization in the design of distributed avionics system and improving the utilization rate of system resourcesa system management configuration method based on distributed avionics system is proposedwhich introduces functional componentsservice roles component instances and system management agentsand defines component-to-component messages and system configuration information tables.Through the system management strategythe restart of the component instancethe master-slave backup of the component instanceand the cold backup of the component instance are realized,thus increasing the task reliability of the system.The system reconfiguration of distributed avionics system is realized without changing the functions of application components and ICD interface.
A radar imaging system based on antenna scanning is proposed.This new system can image the target without radar or target motion.In the process of antenna beam angle scanningpulse compression coding modulation is applied to the radar transmitting signalwhich is synchronized with the beam angle scanningand then pulse compression is applied to the beam scanning angle dimension to improve the angle resolution of the radar.At the same timethe wideband signal is used to improve the range dimension resolutionand the two-dimensional(range dimension and angle dimension)high-resolution radar image of the target is obtained.Simulation is carried out for different signal-to-noise ratiosthe simulation results show that the new radar imaging system is effective.
Aiming at the shortcomings of ball and plate systemsuch as severe PID control oscillationtedious manual PID tuning and poor dynamic qualitya scheme combining Wavelet Neural Network (WNN) identification with WNN-PID self-tuning parameters is studied.Firstlyaccording to the strong coupling characteristics of ball and platea ball and plate system model consisting of two parts is established by Lagrange equation.SecondlyWNN-PID controller is constructed to overcome the problems of tedious manual tuning and poor stability of PID.Considering that gradient descent method and fixed learning rate are easy to fall into extreme valuethe momentum gradient and AdaDec algorithm are used to accelerate the training speed of the network.Thenthe convergence of the system is verified by Lyapunov stability theory.Finally the Matlab simulation shows that the stability and robustness of the proposed stragegy in ball and plate system are better than those of conventional PID and BP-PID strategies.
In view of the shortcomings of traditional matrix pencil algorithm in estimating the parameters of all-pole model under the condition of low signal-to-noise ratiothe calculated values are unstable and the accuracy of pole estimation is not high.FirstlyHankel matrix is introduced into the echo signal for signal decoherencethen the improved TLS-ESPRIT algorithm is used to estimate the poles of multi-band signalsand the improved TLS-ESPRIT based on Hankel matrix replaces the traditional matrix pencil to calculate the parameters of full-band all-pole modelso as to improve the accuracy of the fused signal.The final simulation and measured data show that the proposed method improves the fusion performance of multi-band signals at low SNR.
Aiming at the problem of longitudinal slippage disturbance in the trajectory tracking control of wheeled mobile robotsan iterative learning control method is studied.Firstlyin order to describe the longitudinal slippage disturbanceslippage parameters are introducedand the kinematic model of mobile robot with longitudinal slippage disturbance is established.Then an open-closed loopP-type iterative learning controller is designedseveral representative slippage disturbances are selected for analysisand the stability of the robot trajectory tracking under different longitudinal slippage disturbances is proved by theoretical derivation.Finallythe effectiveness of the designed controller is verified by a simulation example.
Aiming at the problem that the airborne control system is affected by both disturbance and noiseand the traditional disturbance observer is difficult to effectively suppress the noisea noise-reducing disturbance observer is introducedwhich can resist the influence of disturbance and noise at the same time.Firstlythe principle of the traditional disturbance observer is introducedand the reason why the traditional disturbance observer can not suppress noise is analyzed.Thenthe principle of the noise reduction disturbance observer is analyzedand it is found that the system can obtain better anti-disturbance and anti-noise capabilities by selecting appropriate filter.Finallythe controller and the disturbance observer are designedand the simulation experiments are carried out.The simulation results confirm the theoretical analysis that the system has both anti-disturbance and anti-noise capabilities.
Synthetic Aperture Radar (SAR) is a high-resolution space-borne (or airborne) radar systemand Automatic Target Recognition (ATR) in SAR image is one of the key technologies of intelligent image interpretation.Traditional SAR ship target detection algorithms are mostly limited by the scene and have poor generalization abilityso a detection model based on YOLOv3 network is designed.Multi-scale prior box is used to detect the targetand the optimal weight of the model is obtained through training to realize end-to-end target detection.The test results show thatcompared with Faster R-CNN algorithmYOLOv3 has better performance in accuracy and running speed.
A phase plate is designed to extend the depth of field of the initial optical structure.Several considerations and design requirements for the design of wavefront coding optical imaging system are proposed.According to these matters and the basic parameters selectedthe initial structure of an optical system is designed and optimized by Zemax.The initial structure is an imaging objective lens with an object distance of 4 mF number of 3 and effective focal length of 50 mm.The surface type of the selected cubic phase plate is extended polynomial.By setting a complex evaluation functiontaking the cubic coefficient of the phase plate as a variableand then optimizing the phase plate to obtain its parameters.Finallythrough the numerical comparison between the traditional optical system and the optical system with phase plateit is concluded that the depth of field of the design can be extended from 4 m to the range of 2.5 m to 8 m.