To avoid any multi-hypothesis test and the complexity of some probability inequalities, the anomaly detection problem can be converted to the identification of a linear unknown parameter vector. Under priori condition about the number of the anomaly detection, a maximum likelihood identification problem and a non-convex sparse optimization problem are constructed. Then the optimum necessary condition is applied to solve the optimum estimation, and a solvable convex optimization is obtained from the non-convex sparse optimization by adopting a relaxation method. For different norm forms in the convex optimization, the optimum necessary condition and the fast gradient algorithm are respectively used to estimate the optimum values, and some convergence inequalities of the fast gradient algorithm are analyzed. Finally, the effectiveness of the proposed method is verified by the simulation example results.

To avoid any multi-hypothesis test and the complexity of some probability inequalities,the anomaly detection problem can be converted to the identification of a linear unknown parameter vector.Under priori condition about the number of the anomaly detection,a maximum likelihood identification problem and a non-convex sparse optimization problem are constructed.Then the optimum necessary condition is applied to solve the optimum estimation,and a solvable convex optimization is obtained from the non-convex sparse optimization by adopting a relaxation method.For different norm forms in the convex optimization,the optimum necessary condition and the fast gradient algorithm are respectively used to estimate the optimum values,and some convergence inequalities of the fast gradient algorithm are analyzed.Finally,the effectiveness of the proposed method is verified by the simulation example results.

In order to increase the effectiveness of interception missile for target attacking,control of velocity rendezvous angle is required in the terminal engagement.An optimal guidance law with velocity rendezvous angle constraint is proposed for the interception missile,which can control velocity rendezvous angle and terminal miss distance simultaneously.Different from previous research on this issue,the proposed law is suitable for intercepting high-speed maneuvering target.In addition,in the case of centimeter level miss distance,the proposed guidance law requires lesser guidance command to avoid command saturation near the terminal time.Numerical simulation result proved the effectiveness of the guidance law.

Dense false-target jamming can reduce the probability of target detection,and produce the oppressive and deceptive effect on radar target tracking.Aiming at the problem,a technique against dense false-target jamming based active and passive radars data fusion is proposed.Firstly,the measurement data from active radar jammed by dense false-target jamming is pre-processed.Then,associated disposal is made to the pre-processed data and measurement data from passive radar.The associated measurement pairs are kept,and the equivalent measurements are obtained using the least square method.Finally,target tracking is carried out by using the equivalent measurements.The technique makes full use of the advantages of active and passive radars,eliminates the influence of dense false targets,and realizes true-target tracking.The technique is also applicable to the case of no jamming.Simulation results verify the validity of the proposed technique.

Attitude vibration of airborne early warning radar has an adverse impact on target detection performance. Considering the attitude vibration of aircraft for installing airborne early warning radar under rigid body model condition, the aircraft crabbing and rolling models are set up, and then the effects of these two kinds of attitude vibration on clutter spectrum and target echo power is analyzed. Finally, based on single-channel signal processing, the target detection probability under the influence of both crabbing and rolling is obtained by simulation. The results show that: 1)Both crabbing and rolling reduce the detection probability, and the rolling having a more significant influence than crabbing;and 2)When the vibration angle of attitude exceeds a certain value, the radar will lose the capability of target detection.

Based on the principle analysis of passive location of shipborne UAVs,a commom method is given about the position estimation of emitter.The tactics application of passive location of dual shipborne UAVs is studied from three aspects:equal circular error probability curve,ambiguous area in location and the maximum value of the emitter position error.The respective models are established,and practical conclusion is obtained through simulation.The paper provides a theoretic basis and a method for passive locating by shipborne UAVs for destroyer and frigate formation.

To reduce the output signal noise of Hemispherical Resonator Gyro (HRG) in dynamic environment and improve the precision of inertial navigation system,a filtering algorithm based on Lifting Wavelet Transform (LWT) is proposed.The signal is decomposed with wavelet transform lifting algorithm,and then the low-frequency wavelet coefficient is processed with Forward Linear Prediction (FLP) filter,to further remove the low-frequency interference and extract the desired signal.The high-frequency wavelet coefficient is directly to be zeroed or processed according to certain threshold rules,which significantly improves the accuracy of reconstructed signal,and realizes removal of the gyro noise.A comparison of the new algorithm,Kalman filtering algorithm and FLP filtering algorithm is made in detail,as well as an analysis of their de-noising effect.Its verified by the simulation results and actual test data that the new algorithm can effectively reduce the output noise of HRG in dynamic environment,the standard deviation is reduced by about 50% and the operation time is shortened by 30% as compared with Kalman filtering.This filtering algorithm is not only of fast speed and high accuracy,but also with a small amount of calculation and good anti-interference performance,enabling to effectively track the desired signal after filtering.

Azimuth super-resolution has always been a hot research topic in radar domain.For the ill-condition encountered in the solving process,a thorough analysis is made of L1 norm regularization method and its constrained method.Under the premise of the target sparse nature,L1 norm regularization model and its constrained model are established,and a gradient projection algorithm is used to solve them for the large dimensions of radar data.A computer simulation for two equal amplitude point targets is made at different Signal-to-Noise Ratios (SNRs).The preliminary findings show that:1) with the decease of SNR,the resolution effect of both algorithms becomes worse,of which,the constrained L1 norm regularization method has a relatively better resolution under the same condition,and can distinguish the two equal amplitude point targets with a interval of 1/2 half power beam width when SNR is 0 dB;2) the constrained method has a better performance in resolution than L1 norm regularization method,constrained iterative deconvolution algorithm,wiener inverse filter algorithm and Richardson-Lucy algorithm (RL algorithm);and 3) these two norm regularization methods have stronger noise adoptability,which can be used for radar azimuth super-resolution.

For the implementation of RNAV operation by using ground-based radio navigation system needs to select a reasonable station for navigation,a ground-based radio automatic station selection algorithm is proposed with multiple factors into consideration.Based on the information of RNAV airways and DME stations around between ZSSS and ZBAA,a comparative analysis is made of the automatic station selection algorithm considering multiple factors for RNAV airway design with the algorithm only considering a single factor,and the precision of selected DME/DME RNAV is verified.The experimental results show that the proposed multi-factor ground-based radio automatic station selection algorithm can effectively select better stations,avoid frequent switching of stations while switching to a better station in time,as well as ultimately achieving precise positioning of the aircraft,and satisfying the requirements of DME/DME RNAV performance.

With the increasingly wide application of three-dimensional technology in many related fields,it becomes more and more important to accurately acquire the target depth information.A method for acquiring underwater target depth information based on polarization is proposed.Firstly,the background region of image is divided based on dark channel prior,then the polarization of backscattered light is calculated by using the light intensity of background region.The backscattered light intensity of each pixel is calculated in combination of the light intensity and polarization,and the depth information of each channel is obtained with the light intensity attenuation formula of water body,thus acquiring the depth information of underwater target through fusion processing.The experimental results show that the proposed method can accurately acquire the depth information of underwater target with higher accuracy and efficiency than that of the method using dark channal prior.

By taking multi-target assignment in air combat of multiple fighters as a representative application of task synthesis technology,a scheme for solving the multi-target assignment problem was proposed based on task synthesis technology.Firstly,traditional method was used for constructing superiority function of our side,threat function of target,and WSEIAC effectiveness assessment model.Assessment to the combat situation and threat was achieved.Then,the target assignment algorithm with the principle of “attacking the inferior one by the one with superiority” was used together with the task planning assessment and task executing management,and a target assignment scheme was obtained.Finally,the target assignment algorithm and the scheme were simulated by using Bayesian network and task synthesis software.The simulation results verify that the scheme of multi-target assignment is effective.

In order to meet the demand of abundant network traffic in the future,many solutions are proposed by researchers,most of which were based on network virtualization technology.We studied the traffic clustering under network virtualization environment,made analysis to the demand of traffic clustering and some clustering algorithms,and proposed a traffic clustering method based Affinity Propagation (AP) algorithm.Considering the shortcomings of the AP algorithm in traffic clustering,an Optimized Affinity Propagation (OAP) algorithm was designed.Experimental results prove that the OAP algorithm has fine performance in traffic clustering.

Prognostics and health management(PHM) technology is the main method for improving the system availability,maintenance efficiency and reducing the life-cycle cost,which has become a key technology and one of the important goals of future aircraft avionics system design.From the perspective of the development of avionics system and PHM technology,the development status of PHM technology is summarized.The OSA-CBM open architecture of integrated avionics PHM system is introduced,and analysis is given to the key technologies of PHM system.Finally,discussion is presented to the future development of the integrated avionics PHM technology.

Software defects exist in all stages of the software life cycle.The current software defect assessment methods generally investigate only a few kinds of properties,most of which just make a qualitative assessment.In this paper,the authoritative defect databases are introduced.By the relevant databases,the corresponding properties that have comparatively great impact on the software defect are identified.Based on the analysis, the corresponding properties are quantified by applying the method of expertise,and a quantitative software assessment method is presented,which provides an effective reference for subsequent software repair.

A variational level set remote sensing image segmentation algorithm based on fuzzy energy clustering is proposed.The algorithm preserves the feature of variational level set that can use region and boundary information together,while solving the problems of the method in segmenting remote sensing images with noise that the denoising effect is not obvious and the segmentation accuracy is not high.On the basis of obtaining energy functional minimum level set function evolution equation by the variational method,the optimal membership functions are used continually to get variational level set of fuzzy energy clustering.Experimental simulation and comparison results show that:1)the image area segmented with this algorithm has obvious gray scale difference and boundary;and 2)the denoising effect is fine and the segmentation accuracy is better than the other algorithms in comparison.

The images generated by large field-of-view (FOV) optical equipment usually have geometric distortion.It is difficult to make geometric distortion correction in real time for images with high resolution and serious distortion.Based on the model of project system with pre-distortion and the distortion features of large FOV optical system,we proposed a pre-distortion method with the position of the pre-distorted image being adjustable.The corresponding hardware architecture is also proposed for realizing bicubic interpolation calculation.The experiment results show that the proposed method is easy for engineering application and is accurate in distortion correction.

Aiming at the requirements of high resolution,mass of data and high real-time performance for airborne multi-channel audio/video recording systems,a real-time multi-channel audio/video recording system was proposed based on embedded platform.Davinci video processors from Texas Instruments Incorporated (TI) were adopted to control the efficient real-time digitizing,coding and storage for four-channel XGA (1024×768@60 frames/s) videos,one channel PAL (720×576@25 frames/s) video,and two-channel audios.Cyclone devices were exploited to transmit the compressed multimedia data.The testing results show that the system can implement recording and storage of multi-channel audio and video signal with high image resolution and good real-time performance.The system can find wide applications in the field of airborne recorders.

Based on the imaging characteristics of the infrared target simulator,a wide field-of-view (FOV) medium-wave infrared heat dissipation differential optical system was designed taking the improved Cooke type system as the initial structure.The optical system has an FOV of 30°,an exit pupil of 300 mm,an maximum diameter of 220 mm,and the focal length of 240 mm.Based on the principle of optical passive athermalization,a piece of aspheric lens is used.By choosing appropriate glass and focal power,the lens has an MTF superior to 0.4 under the environment of -40~60 ℃ at spatial frequency of 16 lp/mm,and also has good thermal stability and imaging quality,simple structure,and very strong practicability.

The ARINC818 is a uniform standard for the new-generation avionics video bus.Based on the ARINC818,an avionics video system was designed for video sending and receiving.In this system,the protocol of ARINC818 is implemented by FPGA.Because of the programmability of FPGA,the system can be applied to all kinds of video transmission with different resolution and frame rate.Finally,the validity and reliability of the system is verified by an examination of video sending and receiving.

A probability-based two-dimensional (2D) alerting algorithm in independent parallel instrument approach procedure is studied.In view of the problems that there exist fixed modes,extra and delayed alarms in traditional algorithm for independent parallel instrument approach,which may bring poor alerting performance and reduce flight efficiency,a new 2D alerting algorithm is proposed based on probability.This algorithm uses Monte Carlo simulation to obtain the collision probability and the alerting region,in which the collision probability equals to the danger level,to define the alerting condition in combination of the collision curve.Taking a certain airport as the flight environment,different locations of aircraft are selected to verify this algorithm.The results demonstrate that the improved algorithm can effectively eliminate extra and delayed alarms, which can provide a reference for further optimization of the alerting algorithm.

Considering that the induction motor SVM-DTC (Space Vector Modulation Direct Torque Control) method based on torque angle control has the disadvantage of not maintaining a constant maximum torque in dynamic process,we proposed an SVM-DTC method based on torque angle compensation control.Compared with the former method,the proposed method can make the electromagnetic torque remain maximum constantly in the systems dynamic process by compensating for the torque angle,and thus can obtain a faster dynamic response.

External disturbance is transferred from the base to gyro room through the suspension tape of pendulous gyroscope.In order to analyze the transfer rule of the external moment of suspension tape,a model for the swing angle of suspension tape is established by Lagranges equation based on the structure of pendulous gyro north finder,and is solved under the condition that instantaneous impact force,constant external force and simple harmonic external force are acted on the base.The swing angle of suspension tape reflects the moment of external force borne by gyro room when the angle is small.It is proved by experiment that:1) under certain conditions,frequency of the swing angle of suspension tape approaches to that of a simple pendulum;2) under the instantaneous impact force and constant force,the swing angel of suspension tape becomes to simple harmonic vibration from the moment of being stressed,of which,the swing amplitude depends on the external force;and 3) under a simple harmonic external force,the swing angle of suspension tape is a linear superposition of vibration by both the frequency of simple pendulum and external force,and resonance appears when the frequency of simple harmonic external force approaches to the inherent frequency of simple pendulum.

The aerodynamic shape for airborne Electric-Optic(EO) turret has great impact on the aerodynamic characteristics of the plane,the precision of rotation of turret itself and the measurement results of the system performance.An optimal scheme for aerodynamic shape design is presented from the viewpoint of engineering practice.Based on the analysis to aerodynamic shape and aerodynamic characteristics, we proposed several possible aerodynamic shapes,among which an optimal design of turret was obtained through theoretical analysis and CFD simulation experiments.In addition,the application of the proposed method in practice was demonstrated by taking a certain type of helicopter airborne EO turret as an example.

Doppler mismatch exists in bi-phase-coded echo signal of radar altimeter when used for matched filtering.To solve this problem,a ground echo model of radar altimeter is established,and based on a thorough analysis of the power distribution of echo signal and the phase characteristics of echo matrix,an echo Doppler detection and compensation algorithm based on all-phase FFT is presented.In this algorithm,the Doppler frequency and phase compensation factor are obtained through the phase difference value of echo matrix,which is measured by using all-phase FFT.Simulation and experiment results show that the algorithm is effective for phase compensation,and the Doppler detection error is less than 0.3 Hz.