This paper introduces two reasoning methods, deductive reasoning and fuzzy reasoning, and studies issues concerning their applications in submarine attack.With comparative commenting, the similarities of the reasoning frameworks of the two techniques and the significant differences between their essences are revealed.The important roles of the two methods in submarine attack are also examined.Deductive reasoning results are concluded as “applicable without doubt”, and fuzzy reasoning results “applicable with caution”, due to their unique characteristics.

The main factors that have effect on image contrast of extended objects in atmosphere were analyzed.The influence of tilt removal to the image contrast was mathematically investigated, and the optimization of using the absolute difference algorithm for obtaining the tilt was studied.Tilt removal of imaging beam by using a fast steer mirror could enhance the image contrast of extended object, facilitate the later digital image processing, and reduce the time cost for target recognition and tracking, thus it is valuable for improving the photoelectric tracking efficiency of low-contrast extended object.

The cooperative passive guidance by two stations is a brand-new anti-radiation guidance system, characterized by high concealment and strong anti-jamming capability.To cooperative passive target locating problem in the terminal guidance phase of this application, a passive location model of Time Difference of Arrival (TDOA) direction finding nearby very-long baseline was constructed.The change rule of ranging accuracy with the direction angle between the object and station is thoroughly analyzed with this model, as well as the location accuracy that can be achieved in various attack directions.With this result, the optimal condition for missile attack position in the passive terminal guidance phase was analyzed, increasing the accuracy of passive location.Finally, validity of the theoretical analysis was verified through simulation, thus providing a new reference for such applications as cooperative passive guidance by two stations and anti-radiation precision attack.

The state model and observe model of single observer passive location are built up by using the information of Direction of Arrival(DOA) and Time Difference of Arrival(TDOA).To simplify the computation process, a new nonlinear filtering algorithm is constructed using second-order multi-dimension interpolation formula instead of calculating the partial derivative of nonlinear functions.Simulation results show that: The proposed algorithm can be used in single observer passive location in stead of Extended Kalman Filtering (EKF), and can obtain more accurate results with a faster converge speed.

Threat assessment of radiation source is an important function of airborne Radar Warning Receiver/Electronic Support Measure (RWR/ESM).To improve the RWR/ESM ability in the complex electromagnetic environments, an expert system of threat assessment was established based on the pulse sequence pattern.The assessment index was determined taking the pulse sequence pattern as the input by using the power model of radar.The TOPSIS method was used to make the assessment system objective and effective, which can meet the requirements of Electronic Warfare and conform to the working process of airborne RWR/ESM.The simulation proved that the assessment system is effective and feasible.

To the measurement error caused by sensor due to rotor vibration in attitude estimation for quad-rotor aircraft, the data measured by accelerometer and gyroscope are fused through a Kalman filter method, to improve the accuracy of attitude estimation, reduce the noise caused by carrier vibration and solve the gyro drift problem.First, the error types of inertial devices were analyzed, and then a three-DOF (degree of freedom) system model was established, simulation analysis was also made through Matlab.Finally, the feasibility of this method was verified by using an experimental bench with propellers.Experimental results showed that the attitude estimation error was within 2° and was not accumulated over time, basically meeting the requirements of attitude estimation for quad-rotor aircraft, such as real-time performance, low cost and high precision.This method could be successfully applied to the attitude control for quad-rotor aircraft, which can suppress the noise interference, and create a good condition for stable autonomous flight.

Taking optimization of an ISAR serial simulation program as an example, the optimization method for radar simulation operating efficiency is studied based on multi-core computer.First, several commonly used parallel algorithms for radar signal simulation are summarized, including both the advantages and disadvantages of each algorithm, and the parallel granularity of radar simulation is also analyzed.Then, the time consumption of each computing unit, such as the computing unit for target echo generation, for simulation result display, and for pulse compression, is studied, as well as their optimizing strategy.The test results are analyzed.Finally, optimization of the ISAR serial simulation example is carried out by using various strategies, including high performance function library, multi-channel parallel pulse compression, fast recursive algorithm for echo simulation, target echo parallel simulation and pipeline parallelization.After comprehensive optimization, the program runs 6.7 times faster than before, showing the effectiveness and applicability of these optimization strategies.

In order to clarify whether the complex electromagnetic environment is of fractal characteristics or not, a fractal dimensional estimation method based on mathematics morphologic was applied to validate the scale invariance of the signal in electromagnetic environment according to the basic fractal property.Then, self similarity of the signal in the electromagnetic environment was validated by analyzing the relationship between long range dependence and self similarity, and calculating the Hurst index.The multifractal character was also validated by analyzing the partial fractal character of the signal in the electromagnetic environment.Theoretical analysis and simulation results proved that the signal in complex electromagnetic environment possesses fractal characteristic.It lays a foundation for studying complex electromagnetic environment by using fractal theory.

To the complex background suppression problem in infrared small target detection over long distance, a method combining spatial filtering with wavelet filtering was presented.By using the gray-scale morphologic top-hat transform of adaptive structure element in the spatial domain, most infrared background was suppressed.On this basis, the processing space was transformed to the wavelet domain.By analyzing the difference of residual background, target and noise coefficients in high-frequency sub-band, the expression of sub-band coefficient based on neighbor average was defined, a center vector of high-frequency sub-band coefficient was constructed, and the wavelet high-frequency image was integrated to form a distance image, obtaining the final suppression result of infrared complex background.The experimental results show that: Compared with the classic algorithm, the method given here can not only effectively suppress the infrared complex background, but also strengthen the target signal intensity.

Aiming at the shortcoming of the traditional weighted average data fusion method that it demands high integrality of measurement data to measurement equipment, we proposed a real-time data fusion method based on multiple distance measurements of networked scout radars.Under least squares rule, the networking fusion model of scout radars was established, and the initial value choice of the parameters to be estimated, determination of weight coefficient matrix, and fusion precision were studied for model solution.The real-time performance and precision of the proposed method were verified through simulation and analysis.

To increase the penetration probability of anti-ship missile, an effective way is to adopt saturation attack, which requires that multiple missiles to arrive at the target simultaneously.However, the actual flight time of missile is a random variable, which may cause differences in the arrival time of each missile at the target, thus influencing the cooperative combat efficiency of multiple missiles.Based on the time difference model for anti-ship missile saturation attack, such distribution characteristics as probability distribution function, probability density function, mathematical expectation and mean square error of time difference in anti-ship missile saturation attack are given in three respective cases that the actual flight time of missile complies with uniform, exponential and normal distributions.Finally, an analysis and a summary are made through an example, to reach a conclusion that the randomness of actual flight time of missile has a considerable influence on the time difference in anti-ship missile saturation attack, which needs to be taken seriously.

In recent years, the development of Distributed Integrated Modular Avionics (DIMA) brings higher demands on aviation electronic networks.Time Triggered Ethernet(TTE) can guarantee strong real-time communication, improve the quality of network service and indicate the upgrade direction for aerospace electronic networks.In this paper, the requirement of avionics system to network communication is summarized, the characteristics of the avionics network are described, and the advantages of Time Triggered Ethernet are pointed out.The analysis to Time Triggered Ethernet shows that it can satisfy the upgrade of avionics system and is an important direction of the new-generation aircraft network technology in the future.

To the problem that traditional control method for quality controlling is sensitive to the change of aerodynamic parameters, an improved fractional order controller was designed based on fractional order calculus theory and Linear Quadratic Regulator (LQR) optimal control technique.First, state reconfiguration of missile dynamics model was carried out, by using LQR technique and output feedback, a three-loop control structure based on missile optimal tracking index was obtained.Then, a generalized fractional order controller structure was constructed.Parameters of the missile fractional order controller were tuned by an improved particle swarm optimization algorithm, in which both the performance in time domain and frequency domain stability performance and penalty function were combined to construct a fitness function.The controller parameters were set though Particle Swarm Optimization (PSO) algorithm.Simulation results show that the fractional order controller has a good steady and dynamic performance.

The mobility of the ground time-sensitive targets is very strong, and the target attitude information can not be accurately predicted, which may lead to identification difficulties.SIFT algorithm exhibits great performance under a variety of image transformations, such as rotation, scale, illumination and other distortions, but it can only work within a small range of perspective transformation.When encountering large perspective transformation, the recognition rate of SIFT becomes lower.To solve this problem, a ground time-sensitive target recognition method based on edge orientation features was proposed.Firstly, integral images and Haar wavelet template were utilized to calculate the image gradient field, taking the points with maximum module value as feature points.Two points that meet the distance constraints were combined to form a pair of feature points, enhancing the peculiarity of the feature point pairs by using mutual calibration method.The gradient orientation was taken as the matching basis to achieve target recognition.Experimental results show that the recognition method is feasible and effective, which can keep stable within a wide range of perspective transformation.In the experiment, targets within the perspective of 45° can be identified correctly.The method has strong robustness to the perspective transformation, and performs better than SIFT algorithm.

A set of dual-wavelength infrared optical system was designed for airborne photoelectric detection equipment, based on dual-wavelength 320×256 element cooled thermal IR focal plane arrays (FPA) detector.The system adopts the combination of three kinds of material of Ge, ZnSe and ZnS to achieve athermalization design.By introducing harmonic diffractive surface and aspheric surface, the chromatic aberration and the off-axis aberration are well corrected, and the system structure is simplified.The system, working in the wave band of 3.7~4.8 μm /7.7~9.5 μm and with the F/number of 2, is consisted of 6 elements, and has 100% cold shield efficiency.The image quality evaluating results show that: the performance of the dual-wavelength infrared optical system is very well in at temperature from -60 ℃ to +70 ℃.

This paper presents an FPGA based implementation for adding White Gaussian Noise (WGN).By using matrix transformation and XOR operation, uniformly distributed random numbers (UDRN) could be easily generated.Then we used look-up table to convert the UDRN into Gaussian Random Number (GRN) based on Box-Muller method.After GRN was generated, an automatic searching and approaching method was used to add certain White Gaussian Noise on a zero-IF signal to match a SNR demand.Results of simulations and experiments show that the device can be used to add White Gaussian Noise on signals of wireless communication systems.

To satisfy the requirements for isolating disturbances and stabilizing optical axis of a stabilized platform, the performance of the system control is improved by optimizing the control structure and control algorithms.On the basis of the speed closed-loop control, the current inner loop is loaded to improve the torque control accuracy of the DC torque motor.The isolation and the stability margin of the system is improved by cascading the lead and lag correction device.The fuzzy controller tuning PID controller parameters is used to improve the system dynamic performance.Simulink simulation shows that: The system isolating disturbance under constant torque value, periodic disturbance torque and periodic disturbance angular rate has the characteristics of fast response, good isolation effect and high stability.

Application background of the evidence collection system for maritime surveillance is introduced.In combination with its development status both at home and abroad and by reference to the application of POS-aided image location in aerial survey.Large scale topographic map was drawn for target locating.By integration of such equipment as the biaxial servo stabilized platform, high-accuracy Position & Orientation System (POS) and HD video camera, and equipped with corresponding processing software, the airborne evidence collection system for maritime surveillance has the ability of both target reconnaissance and localization with high precision.Preliminary experimental results show that the accuracy of real-time target locating is better than 0.26 m when the flying height is 40 m.

In light of the miniaturization and portability demand for test equipment of infrared system, the basic composition of test equipment was analyzed, as well as the key parts for miniature design.The design of infrared collimator was optimized by optimizing the design parameters, adopting the optical path design of off-axis parabolic multiple reflections, and selecting duralumin as the machining material of lens, which effectively reduces the volume of optical path system as well as the weight of infrared collimator.A small high-effective black-body radiation source structure was constructed by using red copper radiant surface, thermoelectric refrigerator, cooling fins, etc., and a temperature-controlled driving circuit was designed, realizing the small lightweight surface source black-body.Overall weight of the test equipment developed is less than 15 kg, which realizies the goal of miniaturization and portability with desired application effect.

The framework of distributed integrated modular avionics (DIMA) is introduced at first.Then the characteristics of Time-Triggered Ethernet (TTE) are described.Considering the TTEs communication scheduling problem in DIMA architecture, a scheduling method is presented based on TTE cluster cycle, period of TT message scheduling table and remaining time, and analysis is made to the generated TTE communication scheduling table.

For a class of system with matched uncertainties, a fractional order sliding mode controller based on fractional-order theory was adopted to weaken the chattering in the system better while keeping the control precision.The disturbance observer was adopted to estimate the uncertainties in the system.Finally, the system stability was analyzed.It can be seen through simulation that the method adopted can estimate the uncertainties of system effectively and reduce the system chattering greatly.

Based on the aviation channel characteristics, analysis was made to the background and applicable conditions of Egli, Okumura-Hata, and Longley-Rice models.A method for modeling the aviation wireless channel by using Longley-Rice model was proposed, and the simulation algorithm of the Longley-Rice model was deduced out.Simulation was made to analyze the attenuation of the model under different frequencies, different types of climate, and different terrains.Experimental data verify the accuracy and effectiveness of the model, which can provide a reference for aviation communication engineering modeling.

Based on the geometric position relations of space target, space-based observation station and the sun, as well as the CCD detection system performance, the visible conditions of space target relative to observation station is studied, and the visible-light characteristics of space target is also studied on the basis of bidirectional reflection distribution function (BRDF).Taking satellite as an example, according to the orbital parameters, geometrical parameters and surface material properties of satellite, as well as detection system performance parameters, a simulation analysis was made based on STK/Matlab for the visible conditions and visible-light characteristics of different observation stations in satellite observing.The simulation results show that the visible-light conditions of satellite may be affected by various factors, and the CCD detection system performance has significant influence on the visibility of satellite relative to observation station.