快速傅立叶变换用于Fokker-Planck-Landau方程的数值求解

利用谱方法和FFT技术对Fokker-Planck-Landau方程进行了数值求解,研究了均匀空间条件下粒子在速度空间的分布函数随时间的演化。数值计算表明,所用计算方法能够很好地满足质量、动量和能量守恒要求,计算速度与有限差分方法相比大大加快。     

X波段矩形波导宽边复合缝隙耦合器的MPSTD算法分析

针对MPSTD算法在波导宽边复合缝隙问题中的应用,重点研究了X波段标准波导宽边复合缝隙耦合器的缝隙谐振长度和散射参量特性。仿真结果表明,将MPSTD算法应用于波导耦合缝隙问题的分析,可实现对该问题的精确建模,具有较高的计算精度和效率。     

C4ISR/M&S互操作HLA仿真设施

基于仿真互操作标准组织(Simulation Interoperability Standards Organization,SISO)C4ISR/M&S互操作技术参考模型和高层体系结构(High Level Architecture,HLA),C4ISR/M&S互操作HLA仿真设施为架构仿真系统运行体系提出了面向方面框架(Aspect Oriented Framework,AOF)和应用服务平台的技术.AOF能控制C4ISR/M&S互操作所引起的仿真系统结构复杂化,应用服务平台则能丰富仿真系统的运行环境,仿真设施可作为仿真系统通用运行体系的基础组件,支持复杂互操作系统开发.     

矩阵外积法Kalman滤波器在动态GPS定位中的应用

由于计算机有效字长的限制,滤波算法在计算机上实施时易于产生误差积累,误差协方差失去正定性或对称性,从而出现数值计算中的不稳定现象.一般情况下,当状态变量维数超过10时,滤波过程中出现滤波结果不稳定现象概率增大.为了解决滤波器数值计算不稳定问题,实践中提出并应用了许多方法,如自适应滤波、固定增益滤波、平方根滤波等.这些算法的不足是计算繁琐,效率低下.提出一个基于矩阵外积法所设计的快速、稳定的滤波算法,该卡尔曼滤波算法速度快,效率高,数值稳定性好,运算量少,将其应用于动态GPS定位验证了其有效性.     

激光陀螺捷联惯导系统元件误差自标定技术

通过设计一种实用的激光陀螺捷联惯性导航系统自标定算法,保证在外场使用情况下,能对惯性器件误差(三个陀螺漂移和三个加速度计零位)进行精确标定,确保系统长期使用精度.在完成算法设计的基础上,进行了仿真计算,取得满意的仿真结果.     

Electronic warfare in the optical band: Main features,examples and selected measurement data

The paper presents the possibilities of, and methods for, acquiring, analysing and processing optical signals in order to recognise, identify and counteract threats on the contemporary battleground. The main ways electronic warfare is waged in the optical band of the electromagnetic wave spectrum have been formulated, including the acquisition of optical emitter signatures, as well as ultraviolet (UV) and thermal (IR) signatures. The physical parameters and values describing the emission of laser radiation are discussed, including their importance in terms of creating optical signatures. Moreover, it has been shown that in the transformation of optical signals into signatures, only their spectral and temporal parameters can be applied. This was confirmed in experimental part of the paper, which includes our own measurements of spectral and temporal emission characteristics for three types of binocular laser rangefinders. It has been further shown that through simple registration and quick analysis involving comparison of emission time parameters in the case of UV signatures in “solar-blind” band, various events can be identified quickly and faultlessly. The same is true for IR signatures, where the amplitudes of the recorded signal for several wavelengths are compared. This was confirmed experimentally for UV signatures by registering and then analyzing signals from several events during military exercises at a training ground, namely Rocket Propelled Grenade (RPG) launches and explosions after hitting targets, trinitrotoluene (TNT) explosions, firing armour-piercing, fin-stabilised, discarding sabots (APFSDS) or high explosive (HE) projectiles. The final section describes a proposed model database of emitters, created as a result of analysing and transforming the recorded signals into optical signatures.     

Cooperative interception with fast multiple model adaptive estimation

For the case that two pursuers intercept an evasive target, the cooperative strategies and state estimation methods taken by pursuers can seriously affect the guidance accuracy for the target, which performs a bang For the case that two pursuers intercept an evasive target, the cooperative strategies and state estimation methods taken by pursuers can seriously affect the guidance accuracy for the target, which performs a bang-bang evasive maneuver with a random switching time. Combined Fast multiple model adaptive estimation (Fast MMAE) algorithm, the cooperative guidance law takes detection configuration affecting the accuracy of interception into consideration. Introduced the detection error model related to the line-of-sight (LOS) separation angle of two interceptors, an optimal cooperative guidance law solving the optimization problem is designed to modulate the LOS separation angle to reduce the estimation error and improve the interception performance. Due to the uncertainty of the target bang-bang maneuver switching time and the effective fitting of its multi-modal motion, Fast MMAE is introduced to identify its maneuver switching time and estimate the acceleration of the target to track and intercept the target accurately. The designed cooperative optimal guidance law with Fast MMAE has better estimation ability and interception performance than the traditional guidance law and estimation method via Monte Carlo simulation.     

An experiment evaluating how the tiny mass eccentricities in spin-stabilized projectiles affect the position of impact points

This study investigates and quantifies some possible sources affecting the position of impact points of small caliber spin-stabilized projectiles (such as 12.7 mm bullets). A comparative experiment utilizing the control variable method was designed to figure out the influence of tiny eccentric centroids on the projectiles. The study critically analyzes data obtained from characteristic parameter measurements and precision trials. It also combines Sobol's algorithm with an artificial intelligence algorithm—Adaptive Neuro-Fuzzy Inference Systems (ANFIS)—in order to conduct global sensitivity analysis and determine which parameters were most influential. The results indicate that the impact points of projectiles with an entry angle of 0° deflected to the left to that of projectiles with an entry angle of 90°. The difference of the mean coordinates of impact points was about 12.61 cm at a target range of 200 m. Variance analysis indicated that the entry angle — i.e. the initial position of mass eccentricity — had a notable influence. After global sensitivity analysis, the significance of the effect of mass eccentricity was confirmed again and the most influential factors were determined to be the axial moment and transverse moment of inertia (Izz Iyy), the mass of a projectile (m), the distance between nose and center of mass along the symmetry axis for a projectile (Lm), and the eccentric distance of the centroid (Lr). The results imply that the control scheme by means of modifying mass center (moving mass or mass eccentricity) is promising for designing small-caliber spin-stabilized projectiles.     

基于改进核极限学习机和集成学习理论的目标机动轨迹预测

为了提高目标轨迹预测的精度以及预测模型的泛化能力,提出基于改进蝙蝠算法优化的核极限学习机(Kernel Extreme Learning Machine,KELM)和集成学习理论目标机动轨迹预测模型。构建KELM模型,并采用改进的蝙蝠算法对KELM的参数进行优化;以优化后的KELM神经网络为弱预测器,结合集成学习算法生成强预测器,通过训练不断优化强预测的结构和参数,得到一种基于集成学习理论的目标机动轨迹预测模型;基于不同规模的样本,将所得预测模型与逆传播神经网络、支持向量机和极限学习机等模型进行对比分析。仿真结果表明:所提目标机动轨迹预测模型具有较好的预测精度和泛化能力。     

一种含最优变异的多微粒群优化算法

针对微粒群优化算法中的固有缺点,提出了带有最优变异算子的多微粒群优化算法,采用多个微粒群对目标函数进行寻优,并在寻优过程中对子群中最优微粒引入了最优变异算子。通过这样的处理,算法可以预防早熟收敛并具有更快的收敛速度和更好的局部开发能力。对一组测试函数的模拟实验结果表明,带最优变异的多微粒群优化算法可以摆脱局部最优解对微粒的吸引,在较少的代数内就能够获得好的优化结果。