Compressed Sensing (CS) theory has challenged the limitation of Nyquist-Shannon sampling theorem and has a very important impact on signal processing field in recent years. In this paper, the research progresses of CS imaging radar are reviewed. Firstly, based on the basic principle of CS theory, the idea of its application in radar imaging is discussed. Then, the current research development of CS imaging radar is demonstrated, including Synthetic Aperture Radar (SAR), Inverse Synthetic Aperture Radar (ISAR), Multiple-Input Multiple-Output (MIMO) radar, Ground Penetrating Radar (GPR), Through-the-Wall Radar (TWR), Cognitive Radar (CR) and so on. Finally, some challenges faced by the CS imaging radar in its practical applications are discussed, and several suggestions are given on its future development.

In order to solve the problems that the existing blind beam-forming method has complicated structure when using the cascade mode and the stability of the system is unsatisfactory when using the parallel mode, this paper uses the directional accumulation of energy based on the time-frequency analysis to obtain the one-dimensional linear distribution relationship between the intercept and the signal of the frequency axis. Then the uncertainty set of the steering vector is determined according to the second-order difference operation. Finally, the steering vector is accurately estimated by the second-order cone programming constraint. The multi-target, parallel output of blind beams is realized by the Capon beam-forming method. Theoretical analysis and experimental results show that the proposed method is less computationally intensive than the existing method, and can accurately estimate the steering vector and form a beam to receive the desired signal and to suppress the interference signal.

Due to the large aperture imaging of the Frequency Modulation Continuous Wave Circular Synthetic Aperture Radar (FMCW CSAR) wavenumber domain imaging algorithm, the target scattering coefficient changes, so that the imaging cannot be focused. To solve this problem, a sub-aperture FMCW CSAR fast circular convolution imaging algorithm is proposed, and non-uniform Fourier transform is used instead of interpolation to improve imaging efficiency.At the same time, the FMCW CSAR Doppler process is analyzed, and the principle of subaperture division is deduced theoretically. The expression of subaperture selection is given. The simulation analysis shows that the algorithm can effectively avoid the difficulty of combining the wavenumber domain algorithm with the subaperture. The results show that better imaging is possible within the aperture, and it is difficult to achieve good focus imaging beyond the sub-aperture range.

The rotation of the Qball2 quadrotor yaw angle is provided by the reverse torsion, which is more prone to the speed saturation than the pitch and roll angles powered by the lift, and the model has the features of parameter uncertainty, strong coupling, and is susceptible to external interference. To solve the above problems, a Linear Active Disturbance Rejection Control (LADRC) algorithm based on error compensation is used to control the yaw attitude. The LADRC algorithm has the advantages of not based on model, strong anti-interference ability and simple parameter setting. The anti-saturation scheme based on error compensation has a simple structure, high flexibility and good anti-saturation performance. The simulation and Qball2 platform experimental results show that the designed controller can better solve the problem of yaw angle speed saturation and improve the dynamic performance and steady state performance of the system.

The non-commutativity error is generally compensated by the multi-subsample rotation vector method, but the performance of the traditional multi-subsample rotation vector method is degraded under the condition of large half cone angle or other more complicated angular motion. The new multi-subsample quaternion algorithm and the direction cosine algorithm do not directly consider the non-commutativity error, and the two algorithms directly solve the attitude differential equation. In order to comprehensively compare the performance of these algorithms, a simulation analysis is carried out under conical motion and large angle maneuvering conditions. Two data conditions, ideal and non-ideal samplingare used to transform different sampling frequencies, and comparison is made to the computational burden of the algorithms. The results show that under ideal conditions, the periodic error of the new algorithm is smaller than that of the rotation vector method, and the accuracy of the new algorithm is improved significantly with the increase of the number of subsamples. By comparing ideal sampling with non-ideal sampling, it can be seen that the accuracy of the algorithm differs by 4~5 orders of magnitude. Each of the three algorithms has its own advantages and disadvantages. Only by fully compensating the inertial device data can the accuracy potential of the algorithm be fully realized.

The Passive Coherent Location System (PCLS) uses a fixed observer and an non-cooperative Illuminator of Opportunity (IO) to track targets, which is not applicable to a real sea battlefield environment. In response to this deficiency, this paper proposes a PCLS target tracking model based on multiple maneuvering observer and a single maneuvering IO. For the problem that the PCLS target state estimation is imprecise by only using Time of Arrival (TOA), the model takes the joint measurement of TOA and Doppler frequency as the target observation, with the signal's Angle of Arrival (AOA) measurement as the IO observation, so that simultaneous tracking of targets and IOs is achieved. The simulation results prove the validity of the model.

Aiming at the blind extraction of independent sources in linear aliasing signals, this paper proposes an ordered blind extraction algorithm based on Whale Optimization Algorithm(WOA) and Principal Component Analysis(PCA). The algorithm takes the absolute value of the signal kurtosis as the objective function, uses the WOA to calculate the decimation vector, and PCA to reduce the dimension of the mixed signal for removing the components of the extracted signal existing in the mixed signal.Thus the blind extraction is implemented in the order of the source signal kurtosis. Simulation experiments show that the proposed algorithm is effective for extracting blind signals, and the extraction accuracy is high, which has certain practical application value.

A data-driven iterative Adaptive Dynamic Programming (ADP) algorithm including online sampling and offline learning is proposed. The H∞ control problem of the nonlinear system with input constraints and unknown models is solved only by online data. The model-free Hamiton-Jacobi-Isaacs (HJI) equation is derived by using the methods of Policy Iteration (PI) and Iteration Reinforcement Learning (IRL).Three neural networks are constructed. After the online acquisition of system data is completed, the off-line learning method is used to approximately solve the model-free HJI equation, and then the value function, control strategy and disturbance strategy are obtained. The parameter of the neural network is solved by the least squares method. Simulation results verify the feasibility of the algorithm.

This paper mainly studies the decision-making problem of Airborne Warning and Control System(AWACS) when guiding modern fighters to attack multiple targetsanalyzes the advantages of decision-making and guidance by using AWACS, and gives a decision-making route and solution. Based on the threat evaluation and value evaluation to the target , the first target to be attacked and the weights of the rests are determined. Then, the objective function of the occupation decision is constructed to solve the optimal attack route.The simulation result shows that the proposed method can give full play to the intelligence advantage of AWACS, guide the fighter to approach the targets stealthily, and capture and strike the scattered targets in dominant positions.

The probability calculation of hidden failures has a significant impact on the safety assessment results of the initial airworthiness system. Its computational model has complex and diverse characteristics. How to review the security of these models has become a key issue in model development and airworthiness certification. This paper analyzes the factors influencing hidden failure calculation, proposes the certification elements and key points of the calculation model, and uses the currently widely-used engineering methods and calculation models as an example to evaluate and find safety issues, which can effectively promote the safety level of the aircraft.

A time-space steerable point-focusing Frequency Diverse Array (FDA) antenna based on multi-carrier frequency with time-modulated frequency offset is proposed.In order to achieve the tracking of the moving target, a time compensation factor is introduced in the frequency offset to avoid the possible frequency singularity, so that the duration of the continuous frequency modulation is much longer than that of the periodic modulation.Then the frequency offset is calculated according to the real-time position of the target to achieve the goal of keeping the beam focused on the target throughout the whole process of itsmotion. Finally, a simulation example of moving target tracking is given to verify the effectiveness of the method.

Multi-UAV target tracking is a hot topic in recent years. In this paper, a multi-UAV target tracking model is constructed for a directed graph network composed of multiple UAVs, and a distributed fusion processing method is adopted.Based on the multi-UAV target estimation of distributed unscented information filtering, the thesis deduces the weighted average consistency algorithm based on directed graph network, and proposes two weighting matrix design methods. Based on this, a problem solving framework for distributed unscented information filtering consistency algorithm is constructed. The simulation analysis shows that the consistency algorithm based on directed graph network can track the target well under different network topologies, which has good estimation accuracy and robustness, and can improve the performance of multi-UAV fusion estimation.

High-precision correction of radio wave refraction error is one of the key factors for improving the accuracy of radar detection. The accuracy of atmospheric refractive index on radar radio wave ray has a great influence on the accuracy of radio wave refraction correction. In view of the fact that the current linear interpolation method of atmospheric refractive index causes a large error in the refractive index on the radio wave ray, a piecewise atmospheric interpolation method is proposed according to the law of the variation of atmospheric refractive index, in which the linear interpolation method is used on the first section of the atmosphere, and the exponential interpolation method is employed on the second section of the atmosphere.The actual detected data of the atmospheric refractive index is used to compare the refractive indices on the radio wave ray obtained by linear interpolation and piecewise interpolation, and it is proved that the piecewise interpolation method has higher accuracy. The atmospheric refractive index obtained by the two methods is used to calculate the radio wave refraction error. It is proved that the piecewise atmospheric interpolation method can effectively improve the accuracy of radio wave refraction correction, and thus ensure the high-precision detection of the radar.

Compared with traditional airborne phased array radar, the spatial-domain degrees-of-freedom of the airborne Transmit Subaperturing-Multiple Input Multiple Output (TS-MIMO) radar are multiplied, and the training samples required for Space-Time Adaptive Processing (STAP) are also significantly increased, so the performance degrades sharply in the actual non-uniform clutter environment, and slow moving targets cannot be detected. Different from the traditional STAP method, this paper proposes a slow moving target detection method based on two-dimensional space-time sparse super-resolution spectrum estimation. The method uses the sparse Bayesian learning algorithm to directly measure the range cell data for space-time spectrum estimation. Then, the main clutter component in the space-time super-resolution spectrum is set to zero based on the radar prior parameters, and finally the slow target can be detected in the angle-Doppler domain based onconventional constant false-alarm processing. The proposed method does not require training samples, so it can significantly improve the slow moving target detection capability of the onboard TS-MIMO radar in practical applications. Simulation experiments verify the effectiveness of the proposed method.

Aiming at the stochastic degradation device with performance degradation trend in the Step-Stress Accelerated Degradation Test (SSADT), a nonlinear Wiener process is used to establish a step-accelerated degradation model consistent with the degradation characteristics of the device. The Maximum Likelihood Estimation (MLE) algorithm is used to obtain the estimates of prior parameters. The current monitoring data of the target device is used to update the posterior distribution of random coefficients based on Bayesian method. The Remaining Useful Lifetime (RUL) distribution of the device considering the uncertainty of random coefficient estimation is derived by using the full probability formula. The correctness and superiority of the proposed method are verified by an example.

Global shutters have advantages in hyperspectral imaging, mapping, and star-sensing applications for Earth observation, but their application effects also depend on high signal-to-noise ratios. According to the characteristics of CMOS imaging, a low-voltage reference source circuit capable of sourcing and sinking current and a focal plane electron with low thermal distortion are designed. A method of receiving multi-channel serial data with uncertain initial state of power-on is proposed.According to the influence of the parasitic light sensitivity unique to the global shutter, the multi-point fitting correction method based on line-by-line counting and taking the middle line as the reference is adopted.The front-illuminated CMOS imaging system and cooled back-illuminated EMCCD are tested according to EMVA1288 standard.The standard deviation of the single image before and after calibration is 3.37 and 0.42 respectively, the maximum SNR is 123.37, and the maximum SNR of the EMCCD is 359.43. The results show that the correction method can effectively reduce the fixed pattern noise of the global shutter. There is a big gap between the SNR of the area array CMOS in the global shutter mode and that of EMCCD.

The splicing light window has good performance in terms of pneumatic conformality, electromagnetic stealth and large size. However, due to the inconsistent state between the sub-optical windows, the incident wavefronts from the different areas are separated and an additional optical path difference is introduced. Thereby the system Point Spread Function (PSF) is degraded, and the obtained image is blurred. Therefore, analyzing the effect of splicing light window on imaging quality is necessary for the development of high-performance airborne photodetection system. Through the numerical simulation of the image , the factors affecting the optical imaging by the splicing light window are analyzed one by one and the image features and formation causes are determined. At the same time, a design example is given to illustrate the method of reasonably determining the processing precision and surface accuracy of the sub-window.

The oil-driven quad-rotor UAVs have the problems as under-actuation, large time-varying environmental error and high nonlinearity. To obtain a more precise control quantity, a control algorithm based on adaptive integral backstepping method and hybrid filtering algorithm is proposed, which is then used in the control system of an oil-driven quad-rotor UAV with high vibration noise. Comparison experiments are made under the same simulation conditionsand the result shows that: Compared with the integral backstepping method, the UAV using the control algorithm of adaptive integral backstepping method combined with the hybrid filtering algorithm is more robust to the strong noise interference, and the UAV can hover stably with fine control effect.

Aiming at the requirements for fast and precise positioning of helmets in the modern warfare, the paper puts forward a new integrated LOS measurement method.Based on the electromagnetic pose measurement, the inertial positioning method is added to realize fastreal-time and high-accuracy head pose measurement. By using the Kalman filtering algorithm as well as the IMU zero bias estimate, the method combines the electromagnetic with the inertial method for integrated LOS measurement. An effective mathematical model is established according to the principle of LOS measurement, and an experimental platform is set up for testing and verification. The results show that the algorithm can effectively complete the high-precision measurement of the helmet posture.

Aiming at the requirement of 3D reconstruction of big data in oblique photography, the incremental Structure From Motion (SFM) system is studied, and the traditional SFM system is modified. A highly efficient and robust linear incremental 3D reconstruction system is designed and implemented to solve the problems of low efficiency and inability to adapt to big data in traditional incremental 3D reconstruction systems, which provides a complete solution for 3D reconstruction of big data.

The shore-ship communication is an important means of communication between ship formation and land-based command poststhus it is crucial to keep communication smooth.To solve the problem that the random variation of ionosphere affects the simulation of smooth communication zonewe took the one-hop reflection with the highest frequency of wartime communication as an example and carried out visual simulation.Firstlybased on the ionospheric model commonly used in engineeringthe calculation model of reflection height was established.The calculation modeldata sampling and visualization method of the smooth communication area of shore-ship communication with and without interference were proposedand the simulation was carried out based on the simulation platform.The realization effect showed that:It can meet the simulation requirementsand display the communication status more intuitivelywhich provides a method for equipment deployment and work parameter selection.

According to the working principle and operation mode of laser decoy jamming equipment, a simulation test system is designed for evaluating the effect of laser decoy jamming. The system can simulate the laser semi-active guidance threat, and can cooperate with the laser decoy jamming equipment to implement the jamming effect evaluation test for evaluating the laser decoy jamming effect, which supplies a basis for evaluating the jamming ability of laser decoy jamming equipment.