基于信息需求的情报支持效能分析

经典的侦察与监测(S&R)系统效能分析方法存在模型难以建立、结果不准确等问题。考虑到S&R系统的目的是提供情报支持,提出一种基于信息需求的S&R系统情报支持效能分析方法。该方法以用户的信息需求为度量基准量,比较S&R系统性能对信息需求的满足度,并以此满足度作为S&R系统效能度量的指标。仿真实例表明了新方法的有用性。     

多UCAV协同控制中的任务分配模型及算法

任务分配是多UCAV协同控制的核心和有效保证。分析了影响目标价值毁伤、UCAV损耗、任务消耗时间等三项关键战技指标的因素,综合考虑实战中多UCAV同时攻击同一目标和使用软杀伤武器这两种典型情况对UCAV执行任务的影响,建立了针对攻击任务的多UCAV协同任务分配模型,并应用粒子群算法求解。仿真结果验证了模型的合理性和算法的有效性。     

车联网环境下车辆协同高精度定位研究进展

车辆位置信息是许多智能交通应用的基础,如车辆导航、路径规划和车辆编队等.现有研究中融合单车车载多源传感器的定位方法无法有效解决城市峡谷、隧道和立交桥等卫星信号不可用条件下的车辆定位问题.围绕车辆高精度定位进行了综合评述,主要深入研究分析了车辆协同定位技术.首先分析了单车自主定位的关键技术及其主要应用场景;然后对车辆协同...     

融合初值校准与二阶逼近的单星测频定位算法

为减小单星测频定位的误差,提出一种融合初值校准与二阶逼近的单星测频定位算法。该算法在卫星接收信号多普勒频移为零的时间点,通过测距获得卫星到定位目标的距离信息,利用距离信息修正轨道平面与定位目标的几何关系,为初值的选取提供校准手段;将校准的初值代入含二阶级数的定位方程泰勒展开式,通过较少次数的迭代得到定位目标的真实位置,从而降低定位的算法复杂度,提高定位精度。仿真结果表明,所提出的算法与多普勒单星定位算法相比,迭代次数和定位误差大幅度减小,其实现简单、计算量少、误差小,在单星定位研究领域具有较高的理论价值和实用价值。     

Numerical simulation of the blast wave of a multilayer composite charge

The numerical simulation of a blast wave of a multilayer composite charge is investigated. A calculation model of the near-field explosion and far-field propagation of the shock wave of a composite charge is established using the AUTODYN finite element program. Results of the near-field and far-field calculations of the shock wave respectively converge at cell sizes of 0.25–0.5 cm and 1–3 cm. The Euler––flux-corrected transport solver is found to be suitable for the far-field calculation after mapping. A numerical simulation is conducted to study the formation, propagation, and interaction of the shock wave of the composite charge for different initiation modes. It is found that the initiation mode obviously affects the shock-wave waveform and pressure distribution of the composite charge. Additionally, it is found that the area of the overpressure distribution is greatest for internal and external simultaneous initiation, and the peak pressure of the shock wave exponentially decays, fitting the calculation formula of the peak overpressure attenuation under different initiation modes, which is obtained and verified by experiment. The difference between numerical and experimental results is less than 10%, and the peak overpressure of both internal and external initiation is 56.12% higher than that of central single-point initiation.     

Study on performance degradation and failure analysis of machine gun barrel

An increase in the use of the gun barrel will cause wear of the inner wall, which reduces the muzzle velocity and the spin rate of the projectile. The off-bore flight attitude and trajectory of the projectile also change, affecting the shooting power and the accuracy. Exterior ballistic data of a high-speed spinning projectile are required to study the performance change. Therefore, based on the barrel's accelerated life test, the whole process of projectile shooting is reproduced using numerical simulation technology, and key information on the ballistic performance change at each shooting stage are acquired. Studies have shown that in the later stages of barrel shooting, the accuracy of shooting has not decreased significantly. However, it is found that the angle of attack of the projectile increases as the wear of the barrel increases. The maximum angle of attack reaches 0.106 rad when the number of shots reaches 4300. Meanwhile, elliptical bullet hole has appeared on the target at this shooting stage. Through combining external ballistic theory with simulation results, the primary reason of this phenomenon is found to be a significant decrease in the muzzle spin rate of the projectile. At the end of the barrel life, the projectile muzzle spin rate is 57.5% lower than that of a barrel without wear.     

Analysis of the stress wave and rarefaction wave produced by hypervelocity impact of sphere onto thin plate

Shock wave is emitted into the plate and sphere when a sphere hypervelocity impacts onto a thin plate. The fragmentation and phase change of the material caused by the propagation and unloading of shock wave could result in the formation of debris cloud eventually. Propagation models are deduced based on one-dimensional shock wave theory and the geometry of sphere, which uses elliptic equations (corresponding to ellipsoid equations in physical space) to describe the propagation of shock wave and the rarefaction wave. The “Effective thickness” is defined as the critical plate thickness that ensures the rarefaction wave overtake the shock wave at the back of the sphere. The “Effective thickness” is directly related to the form of the debris cloud. The relation of the “Effective thickness” and the “Optimum thickness” is also discussed. The impacts of Al spheres onto Al plates are simulated within SPH to verify the propagation models and associated theories. The results show that the wave fronts predicted by the propagation models are closer to the simulation result at higher impact velocity. The curvatures of the wave fronts decrease with the increase of impact velocities. The predicted “Effective thickness” is consistent with the simulation results. The analysis about the shock wave propagation and unloading in this paper can provide a new sight and inspiration for the quantitative study of hypervelocity impact and space debris protection.     

国际海洋法与维护国家海洋权益

海洋权益是指沿海国对属于自己的管辖海域享有国际海洋法所赋予的特定主权权利。《联合国海洋法公约》奠定了现代国际海洋法制度的基础,为各国维护正当的海洋权益提供了基本法律依据,但也有不完善甚至严重缺陷之处。认真研究其利弊,以切实维护国家海洋权益和公正合理的国际海洋法律秩序。     

巨额财产来源不明罪法理检讨及完善

巨额财产来源不明罪是学界中争议较多的一个罪名。通过考察本罪的客观要件,“可以责令说明来源”不是本罪的构成要件,仅是司法机关调查案件的法定程序,因此,本罪存在自首;本罪的法定刑基本适宜,为便于司法实践,有必要对该罪的法定刑加以细化并设置财产刑;仅靠刑法不能抑制本罪的发生,应完善前置制度等非刑罚措施。     

容器设备破裂泄漏危险性研究

对容器设备泄漏源的模式进行了分类,分别从泄漏物物态、泄漏面积、小孔泄漏孔形、内部压力、液面高度、泄漏物密度六方面对容器设备破裂泄漏的危险性进行了分析,并提出了避免破裂泄漏的防范措施,具有一定实用意义。