X-47B无人空战系统及其对抗途径分析

X-47B型无人空战系统是当今最先进的无人机系统之一,势必给现有电子对抗技术及装备带来严重冲击.从其任务使命、系统功能、特色技术入手,分析对其实施电子对抗的技术难点和可能的薄弱环节,探讨对X-47B进行侦察探测和电子对抗的技术途径.     

The effect of the longitudinal propagating waves on the electron acceleration in the reconnecting current sheet

Based upon the most efficient electron acceleration near the midplane of 3D non-neutral driven reconnecting current sheet (RCS) and the electrostatic wave excitation by the drift Maxwellian distribution of electrons in Vlasov simulation, we assume that the electrostatic waves mainly propagate opposite to the reconnecting electric field and investigated how these waves affect the electron acceleration. The main results are: (1) when the electron’s velocity equals to the phase speed of the waves, they will be trapped and have the different accelerating characteristics from the untrapped electrons through solving the momentum equations of electrons analytically; (2) the test particle simulations further prove that the number of the energetic electrons decreases with the increasing intensity of unstable waves, and the distribution of the energetic electrons takes on the double power-law.     

Cycle slip detection using multi-frequency GPS carrier phase observations: A simulation study

The detection and repair of the cycle slip or gross error is a key step for high precision global positioning system (GPS) carrier phase navigation and positioning due to interruption or unlocking of GPS signal. A number of methods have been developed to detect and repair cycle slips in the last two decades through cycle slip linear combinations of available GPS observations, but such approaches are subject to the changing GPS sampling and complex algorithms. Furthermore, the small cycle slip and gross error cannot be completely repaired or detected if the sampling is quite longer under some special observation conditions, such as Real Time Kinematic (RTK) positioning. With the development of the GPS modernization or Galileo system with three frequencies signals, it may be able to better detect and repair the cycle slip and gross error in the future. In this paper, the cycle slip and gross error of GPS carrier phase data are detected and repaired by using a new combination of the simulated multi-frequency GPS carrier phase data in different conditions. Results show that various real-time cycle slips are completely repaired with a gross error of up to 0.2 cycles.     

航空电源转换器功能检测系统软硬件设计

主要介绍了航空电源转换器功能检测系统的基本构成以及软硬件实现方法。利用PC机界面来操纵控制单片机对航空电源转换器进行功能测试，使得该系统操作简单方便，可视性增强。     

精确打击武器与精确制导技术

介绍了精确打击武器的基本分类以及不同的打击武器采用的不同的制导技术。分析了国外的精确打击武器中采用的制导技术，指出了精确打击武器及其制导技术是现代高科技武器发展的关键技术。     

计算机翼跨声速压力分布的格林函数方法

本文给出一种用格林定理将跨声速小扰动速势方程化成积分方程式,然后进行数值求解的方法,文中对场元强度进行松弛迭代,一般只需20次左右即达收敛。算例表明,该方法结果与差分法结果一致。     

对涡喷七发动机全加力状态温度高推力小的剖析和排故措施

 涡喷七发动机全加力状态温度高推力小问题,是长期没有解决的生产关键。文章从实际出发,进行理论计算和统计分析,从而找到产生故障的原因,其中有大气湿度的影响,发动机涡轮部件性能退化,~t4温度受大气温度的影响和~t4温度场的不均匀性。针对以上原因,提出了行之有效的排故措施,对解决我国当前使用的双转子发动机经常出现的温度高推力小问题有广泛的现实意义。     

燃烧室内三维层流的数字模拟

本文以SIMPLE方法为基础,发展了一种模拟燃烧室内三维层流的数值计算方法和计算机程序.对存在冷却槽、主燃孔等不同流动条件下的流态进行了数字模拟.所得结果与已有的数值计算结果的一致性良好.     

无人机分类研究

根据无人机设计规范研究需要,本文首先对现役和在研的无人机分类进行统计分析,然后参考有人机和导弹的分类,再考虑21世纪无人机的发展,将固定翼、轮式起落架起飞/着陆的无人机划分为战术类、战略类和作战类三类无人机是科学的、合适的。     

压电陶瓷短圆柱耦合振动的研究

 压电陶瓷圆柱振子的振动问题,由于厚向振动和径向振动之间的耦合作用,使问题变得非常复杂。迄今为止,许多研究者在这方面所做的工作,大体上可分为两类:一类是从各向同性圆柱体振动的近似解出发,求解压电陶瓷圆柱振子的振动问题;另一类是从压电陶瓷圆柱振子的压电本构方程组和运动方程组出发,利用数学上的伴随算子法计算其数值解。这两种方法不仅运算过程都相当复杂,而且都不能直观地反映出压电振子的物理参数的影响。