用于三叉戟武器系统的 GPS 测量设备

随着卫星导航全球定位系统(GPS)工作全面铺开,对该系统正在开展许多应用研究。本文讨论三叉戟Ⅱ(D-5)导弹使用的 GPS 测量方案以及海军为试验评定三叉戟Ⅰ(C-4)武器系统使用的 GPS 方案发展过程,包括为靶场安全实时跟踪导弹和对三叉戟导弹制导系统性能进行事后评定所用的转发 GPS 信号概念(精密跟踪)。文中介绍了为完善跟踪系统提供靶场安全信息而采用的伪卫星 GPS 信号。为了确保所有地面站在时间上有效地同步工作,使用了 GPS 发送的时间信号。本文着重介绍有关 GPS 靶场测量设备的独特的设计特点。     

GPS失锁情况下基于神经网络的组合导航算法研究

文中针对GPS/SINS组合导航系统中GPS信号失锁问题进行研究,采用基于神经网络的组合导航算法.在GPS信号失锁时间段内,用神经网络模拟GPS的信息,进行信息融合.文中给出了基于神经网络的组合导航系统模型,并进行了数学仿真研究,结果表明,引入了神经网络的组合导航系统,在GPS信号失锁时,能保证一定的导航精度.本文为组合导航系统中GPS信号失锁问题的解决提供了一种方法.     

GPS系统仿真和软件GPS接收机的研究

文中介绍了由MATLAB实现的GPS系统仿真和软件GPS接收机的研究.GPS系统仿真包括对GPS卫星轨道、GPS测距码(CA码)及其扩频传输、电离层和对流层导致的噪声、GPS信号的捕获和跟踪过程等各个关键环节的仿真;软件GPS接收机由现有实验室器件构成,能根据存贮的数字化GPS信号进行非实时定位.     

一种基于矢量跟踪的GPS/INS 深耦合跟踪环路设计

针对 GPS 与 INS 两路数据更新频率不一致的问题,提出一种基于矢量跟踪的 GPS/INS 深耦合跟踪环路设计方法.利用滤波外推与CIC滤波相结合的方法,将误差修正后惯导信息回馈到各矢量信号跟踪信道,以调控伪码和载波数控振荡器(controlled oscillator,NCO),实现了跟踪环路的闭合,最终建立起了两路相互独立数据之间相互辅助、相互修正的关系.仿真实验结果表明,设计的GPS/INS深耦合跟踪环路能实现低载噪比和高动态信号的跟踪.     

无重置联邦滤波及在组合导航中的应用

对联邦滤波器的结构及联邦滤波器的无重置融合算法进行讨论,并建立了组合导航系统联邦滤波模型.以SINS/GPS/TAN组合导航系统为例进行了仿真研究.结果表明,文中给出的无重置联邦滤波器与集中卡尔曼滤波器的精度相差无几,解算速度更快,容错性更好,可应用于对实时要求较高的组合导航系统中.     

基于DDS的调频步进毫米波前端的实现

文中给出了一种基于DDS的调频步进毫米波前端的设计,重点讨论了调频步进信号和高稳定毫米波本振信号的实现方法,给出了实现调频步进毫米波前端的框图.在不增加毫米波前端复杂程度的前提下,基于DDS和PLL技术可以产生多种形式的雷达信号,说明设计具有很好的灵活性.文中还给出了相应的硬件框图、软件流程图,并对实际设计的前端进行了调试,给出了实测结果.     

BOC信号跟踪技术的研究

BOC调制是通过将扩频码与一个频率为扩频码速率的整数倍的方波副载波相乘得到。由于其自相关函数的多峰性，将增加这种信号的捕获难度和误跟踪的可能性。文中通过讨论BOC（1，1）信号，详述了BOC（1，1）信号的跟踪模糊问题，找出了一种适合其本身的码跟踪技术，并给出一种改进的适用于新的相关函数的鉴相器算法。这种算法消除了边峰带来的误跟踪威胁。最后通过仿真验证了所述算法的正确性和有效性。     

基于AHP的跟踪算法性能评价研究

针对跟踪算法评价方法不够健全的问题,文中提出了基于AHP法的跟踪算法评价方法。主要从跟踪算法的跟踪准确度、算法的实时性以及算法的硬件可实现性这三个指标考虑了算法性能的评价问题,讨论了三个指标量化和规范的方法,运用AHP法给出了计算各个指标的权重和综合评价分数的方法。最后采用4种典型的跟踪算法和实际拍摄的红外图像序列进行了小目标的跟踪实验,并根据实验得到的数据计算了算法的评价分数,结果表明了文中跟踪算法评价方法的合理性。     

移动卫星通信天线系统的矢量控制法

本文论述移动卫星通信天线系统的矢量控制方法,采用天线对准卫星不依赖于卫星信号,并且借助于捷联惯导系统的数字平台可以排除角运动干扰和长距离线运动干扰。为实现在赤道附近大范围地区的移动卫星通信,本文讨论了方位-俯仰与横滚-俯仰两种结构的矢量控制方法和它们的控制方程。另一台MEMS捷联惯导系统安装在天线上,给出了天线导航参数。天线信号的极值搜索法提高了跟踪精度。GPS信号用于与捷联惯导系统构成GPS/SINS组合系统以修正捷联惯导系统的误差,最后给出了移动卫星通信天线矢量控制系统方框图。     

一种GPS软件接收机的同步算法研究与仿真

空间卫星的高速运动、钟差、GPS接收机应用平台的高动态性是影响信号同步的主要因素。为了积极应对这些因素对系统同步带来的挑战,实现对导航电文准确、快速解调的目的。文中基于对圆周捕获算法、非相干全时间超前-滞后码跟踪环及Costas载波跟踪环工作机理深入研究的基础上,提出了一种GPS软件接收机的同步算法,并通过仿真验证了该算法的有效性、合理性,从而为今后我国发展多种类GPS接收机应用平台提供现实依据。     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

Stability of the Third Generation Intensifier under Illumination

The stability under illumination of transmission-mode GaAs photocathode sealed in the third generation intensifier is investigated by use of spectral response testing instruments. The variations of spectral response with the illumination times under weak and intense illumination are compared. The variations of photoemission performance parameters are also characterized. The results show that during initial several weak illuminations photocathode behaves no evident decay and a maximum sensitivity is achieved, while under intense illumination the sensitivity of photocathode begin to decrease largely at the first illumination. The calculated performance parameters show that the variation of surface escape probability with illumination times is a direct cause of instability of photocathode. It is also found that under intense illumination peak wavelength is moved towards short-wave and peak response is decreased, which shows that the ability of long-wave response of photocathode is decreased.     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Experimental Study on the Small Flyer Initiating Behavior of Fine-grained Explosives

The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.     

Passive Acoustic Radar for Detecting Supersonic Cruise Missile

A Passive Acoustic Radar is presented as a necessary complement to electromagnetic wave radar, which will be expected to be an effective means for detecting cruise missiles. Acoustic characteristics of supersonic flying projectiles with diverse shapes are expounded via experiment. It is pointed out that simulation experiment could be implemented using bullet or shell instead of cruise missile. Based on theoretical analysis and experiment, the ““acoustic fingerprint““ character of cruise missile is illustrated to identify it in a strong noise environment. After establishing a locating mathematical model, the technique of acoustic embattling is utilized to resolve a problem of confirming the time of early-warning, considering the fact that velocity of sound is much slower than that of light. Thereby, a whole system of passive acoustic radar for detecting supersonic cruise missile is formed.     

Algorithm for Multi-laser-target Tracking Based on Clustering Fusion

Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.     

Robust Graded Sliding Mode Tracking Control for Low Speed Spinning Ballistic Missiles

The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent ＂explosion of terms＂. Owing to the upper bounds of the uncertainties are difficult to obtain in advance, adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.