Different from the ordinary cockpit displays，the background of helicopter head-up display is the real outside scene and thus the readability of the displayed picture is easily disturbed by the outside environment. A method was proposed based on Perceived Just-Noticeable Difference (PJND) theory for evaluating the readability of helicopter HUD in complex visual environment.The relationship between the satisfactory PJND value and the environment factors (luminance and chrominance) was studied through experiments. On this basis，a luminance control curve satisfactory for the readability of HUD was designed. Experiment results showed that:1) The PJND value can synthetically reflect the effect of luminance and chrominance on the readability;and 2) The luminance control curve designed based on PJND value can satisfy the requirement on readability of the helicopter HUD.

In order to improve the efficiency of anti-submarine patrol aircrafts in sonobuoy patrol search, the concepts of standard single-row array and the standard complex array are put forward, and the models for determining the parameters of the standard single-row/complex array are established. The practical parameters of standard single-row/complex array are obtained by means of model analysis and calculation. The basic principles for multiple aircrafts to deploy the linear array cooperatively are proposed.Two types，totally four kinds methods for multiple aircrafts to deploy single-row arrays, and the methods for synthetically deploy complex arrays, are given, which provides a basis for anti-submarine patrol aircrafts in patrol search planning.

It is difficult for the jammer to generate a false target with a high degree of threat to interfere the radar.In order to improve the sheltering effect of false targets on real targets, a method for promoting the threat level of false target based on Digital Radio Frequency Memory (DRFM) is presented.According to the operating principle of DRFM, three kinds of interference models combined with power reverse forwarding deception jamming are summed up. By adjusting the parameters of the interference model, all aspects of the false targets are improved. According to simulation calculation result of the interference implementation process, this method can form continuous and stable false tracks, and the threat level of false targets is higher than that of the real targets. Therefore, the validity of the method is proved.

A UAV remote sensing load storage device was designed by taking a certain type of UAV as the flight platform. Considering the problems of magnetometer errors and carrier magnetic interference in measurement, we proposed a method for magnetic field measurement error compensation based on Particle Swarm Optimization (PSO). The data measured by the triaxial magnetometer was taken as the system input, and PSO was used to solve the magnetic interference compensation model. After the magnetic field data of the target signal was obtained, it was compared with the geomagnetic field data obtained from the optical pump magnetometer, which was taken as the real scalar value. The experimental results showed that the PSO based error compensation method in magnetic field measurement has higher compensation precision and certain value for engineering application.

In the course of carrier aircrafts landingthe officer must arrange a safe and efficient landing sequence according to such uncertain factors as the flight states of the aircrafts and the external conditions.The paper mainly focuses on the carrier aircraft landing sequencing problem.Besides the influence of various factors on the landing sequencethe influence of failed landing is also taken into consideration.An optimal mathematical model taking the reducing of delay time and delay cost as its objective is built.Considering the deficiency of the traditional genetic algorithman improved genetic algorithm is proposed and used to solve the model.Simulation result shows thatthe optimized landing sequence can effectively reduce the delay time and delay costand thereby improve the utilization rate of the carrier deck.

To deal with the problem of cooperation of multiple heterogeneous UAVs for target searching and attacking in unknown environment, and with consideration of the resources of the UAVs and the targets, a method of coalition formation was used to complete the task.A multi-objective optimization model was established, and a parallel Non-dominated Sorting Genetic Algorithm(NSGA-II) was proposed to solve the problem. A simulation was carried out and an analysis was made to the running speed of the algorithm, which was compared with the traditional methods. The simulation results verified the rationality of the model, and showed that the parallel NSGA-II has a strong real-time performance and improves the efficiency of task performing.

The judgment about the main direction of the enemy air attack is very important for operational command. This paper focuses on the need of decision-making for air defense of critical area and analyzes the nine major indicators that affect the main direction of the air-raid target. With consideration of the minimum deployment spacing between the firepower units, the gray relational clustering method is used to rationally divide the sub-directions. The Principal Component Analysis (PCA) method is used for dimensionality reduction of the impact indexes, which reduces the correlation among the indexes and the calculation cost. A comprehensive evaluation model is built to calculate the sorting of the directions.The results show that the method is correct and feasible.

This paper presents a fast and accurate Random Sample Consensus (RANSAC) algorithm based on sampling optimization. Firstly, the prior probability of the matching points is calculated by the similarity measurement of matching points, and the minimum subset for model fitting is selected randomly according to the prior probability, which is tested on all the data, until the suboptimal model is found through iteration. Then, the interior point set corresponding to the suboptimal model is used as the initial set for sampling and the minimum subset of the model is randomly extracted and tested on all the data. If the model is better, then the initial set is updated, and the optimal model is found through iteration. Finally, the optimal model is selected, and the interior point and the final model parameters are obtained. The images with different changes are selected as the experimental data, and the algorithm is tested on both the algorithm operation efficiency and the model precision.The experimental data show that the number of iterations in this algorithm is about 20%, and its running time is about 25% of the standard RANSAC algorithm, and the standard square root error is reduced by about 30%.This paper makes full use of the prior knowledge of the matching point and the results of the model test to optimize the sampling mode, so that the operation efficiency and precision of the algorithm are greatly improved.

To determine the number of projectiles in Future Airspace Window (FAW), we deduced the damage probability formula for the future airspace window with many projectiles configured for each aiming point according to the optimal firing density of the future airspace window, and analyzed the feature of the formula. Based on the formula, the methods for calculating the number of the projectiles under predetermined damage probability or predetermined derivative of damage probability, and the number of aiming-points under predetermined number of projectiles, were provided.The simulation example showed that, the results of damage probability obtained though the formula were nearly the same as that obtained through analytic method. In both cases, the damage probability result of simulation was basically the same as theoretical result, which means that the method has certain feasibility.

Taking a six-rotor UAV as the controlled object, and considering the shortcoming of the classical control allocation method that the motor speed command value will become saturate when the control input value is too large, we propose an improved scheme for control allocation according to the weights. The weight coefficient is updated in real time according to the changes of the control input value to avoid saturation of motor speed. The simulation results show that, the proposed method can improve the rationality of allocation, reduce the coupling of each channel, enhance the anti-saturation capability of the six-rotor UAV effectively, and improve the flight performance of the UAV.

An improved Intelligent Single Particle Optimizer (ISPO) algorithm is proposed for 3D route planning of Unmanned Aerial Vehicles (UAVs). The ISPO algorithm is applied to the route planning, and the attracting effect between sub-vectors is introduced to the improved algorithm, which effectively overcomes the shortcoming that the algorithm is easy to fall into the locally optimal solution.Simulation experiments are carried out, in which the improved ISPO algorithm, the Particle Swarm Optimizer (PSO) algorithm with dynamic inertia coefficient and the PSO with reverse-learning and local-learning capabilities (RLPSO) are applied to the route planning. The simulation results show that the improved ISPO algorithm has the best searching precision and ability in the route planning, and its efficiency is higher than that of the other two algorithms.

Since it relies on the current new sample, the original compressive tracking algorithm does not perform well, especially in the case of occlusion.In order to improve the tracking accuracy when there is occlusion, the invariant moments of samples are extracted by means of sample blocks, which are used as the classifying standard of Bayesian classifier. Then, the difference of the invariant moments between two sequential frames is calculated, and the value is used to judge whether the object is occluded or not, thus to achieve adaptive updating of the classifier. Experiments show that:1) The algorithm has good tracking results when the object is partially occluded, and is robust to scale changes;2) The tracking accuracy is improved compared with that of the original algorithm; and 3) When the object is 25×69 pixels, the average processing speed is 58 frames per second, which meets the real-time requirements.

To address the issue of airspeed measurement based on the acoustic vector sensor, an airspeed estimation algorithm based on the temporal and spatial expansion MUSIC algorithm is proposed. Firstly, it is concluded by theoretical analysis that only two wavefronts are superimposed at any point in the Mach cone formed by the supersonic flow, and that the two wavefronts can be considered to be created by two coherent “equivalent sound sources”.On this basis, the distribution model of the sound wave in the supersonic steady flow is built. Then, by employing the measurement model of the acoustic vector sensor, the supersonic airspeed estimation is realized based on the temporal and spatial expansion MUSIC algorithm. A failure analysis of the measurement model is carried out, and the estimated CRB bound is derived. The simulation results verify the effectiveness of the proposed algorithm.

The detection and recognition of acoustic target is an important method to compensate for the weakness of radar in low-altitude detection. How to eliminate the noise mixed in the acoustic signal and to retain the useful information as much as possible is still a challenging problem.Inspired by the wavelet threshold, and according to the characteristics of low-altitude battlefield ambient noise, we proposed a new denoising method based on threshold Empirical Mode Decomposition (EMD). Firstly, the signal is decomposed by EMD to obtain the Intrinsic Mode Functions (IMFs). Then, threshold processing is made to the IMFs whose actual energy exceeds the estimated energy. Finally, the processed IMFs are reconstructed to obtain the denoised signal. To evaluate the performance of the proposed methoda simulation is performed using helicopter sound signal corrupted with typical low-level ambient noise under different signal-to-noise ratios.The performance is evaluated in terms of SNR, Root Mean Square Error(RMSE), and smoothness index, and a comparison is made with those of the previous denoising methods.The simulation results show that the proposed method is effective in eliminating most low-altitude ambient noise.

The airfoil flutter problem of the hypersonic vehicle and the relation of the damage it causes with the airfoil stress are analyzed. Firstly, the binary airfoil model of the hypersonic vehicle is studied, and the dynamic model of airfoil flutter is established. The unsteady aerodynamic force of the wing is calculated out by using the piston theory, and an analysis is made to the flutter of the wing at a certain flight speed. The influence of airfoil flutter stress on the damage caused by wing flutter is studied by using the stress-strain (σ-ε) model, and the strain and fatigue life (ε-N) model. The simulation results show that wing flutter damage is closely related to the amplitude of the flutter, which provides an important reference for the wing reliability analysis in engineering practice.

The satellite detection and identification is critical to the mobile communication antenna tracking system. A satellite signal detection and recognition system based on FFT was designed and implemented. In the system, the recognition rate is ensured by detecting the satellite beacon signal for satellite recognition, and the frequency deviation is corrected by real-time FFT at the satellite tracking stage, so that the frequency deviation is kept within a certain range. Therefore, the accuracy and stability of the antenna in target-satellite tracking are improved.

In order to provide precise guidance for the landing of carrier-based aircrafts, the phased array antenna and the principle of time reference beam scanning are used in the carrier-borne Microwave Landing System (MLS).Ship motion may change the relative position of antenna elements, which will cause the guidance error. In this paper, the models of phased array antenna pattern and antenna vibration error are established, a simulation analysis is made to the effect of phased array antenna's random vibration in three axial directons on the guiding performance of carrier-borne MLS, and a scheme is proposed for suppressing the guidance error of the MLS caused by ship motion. The simulation results show that, the algorithm can stably track the random motion of the ship body, make motion compensation to the phased array antennas of carrier-borne MLS in three dimensions, greatly improve the quality of the received signal, and improve the guidance performance of MLS to a certain extent.

To the attitude control problem of the quad-rotor Unmanned Aerial Vehicle (UAV) with actuator malfunction and external perturbations, a Fault Tolerant Control (FTC) controller was designed based on the model reference adaptive control.By analyzing the dynamic characteristics of the quad-rotor UAV, the actuator failures were added to the system model, and a dynamic model with failed actuator was obtained. The adaptive law of the designed controller was driven by the error signal of the reference model and the model with actuator failure, which can achieve better attitude control. The asymptotical stability of the proposed controller was proved by using Lyapunov method.The result of simulation with Matlab showed that, the proposed controller can track the reference attitude angle in the cases of external perturbations and actuator failures, and the method is feasible and effective.

To address the detection needs of the infrared thermal imaging system，an infrared surface-source blackbody was designedwhich was composed of purple-copper radiant surface，thermoelectric cooler and cooling fin，etc.The high-precision acquisition of the environment temperature and the radiant surface temperature was realized by using the platinum thermistor and 24 bit AD sampling. To solve the problems in the blackbody of big time constant，response lag，persistent disturbance of the environment temperature，a fuzzy PID controller was designed. The control parameters of it were set in real time according to the error and the error variation rate.The goals of small overshoot，rapid response speed and high steady-precision were realized. It is proved by experiments and tests that the temperature control precision is ±0.03 ℃，and the response time is less than 180 s，which meet the design requirements.

Due to the diversity of sample space, it is difficult to calculate the model of the potential function, and therefore difficult to obtain the parameter estimation of Markov random field model. To solve the problem, a parameter estimation algorithm for Markov random field is presented based on Maclaurin series. This algorithm employs a second-order expansion of Maclaurin series to derive the approximate expressions of the potential function and the likelihood function.The system of nonlinear equations corresponding to the Maximum Likelihood Estimation (MLE) is derived, which is calculated by Newton iteration method, and its solution is the MLE for Markov random field. An updated approach is presented and used to calculate the optimal observed value of the degradation model for noisy images based on Gibbs sampling for accelerating the simulation annealing. Tests have verified the effectiveness of the algorithm from three aspects of visual effect, peak signal to noise ratio, and iteration times.

The identification of the threat radar signal is an important task of the radar reconnaissance system, and is one of the factors that affect the success or failure of the countermeasure. Considering the complex electromagnetic environment with the increasing number of radars, the diversity of signal modulation modes and the increasing signal density, we proposed a new method for threat radar signal recognition based on TOA folding clustering. The method firstly performs TOA folding and sorting of the intercepted pulse stream, then extracts the data with DBSCAN clustering algorithm, and finally performs the template matching recognition of the threat radar signal. The simulation results show that the method can sort out the target radar signal in complex environment, and can adapt to the complex modulation of radar signal.