一种基于Q-R矩阵分解的自适应滤波算法

由于计算误差等因素的影响,致使滤波协方差阵不对称或负定,从而导致滤波器发散,影响滤波算法的收敛速度和稳定性。在机动加速度"当前"统计自适应卡尔曼滤波算法的基础上,引入了基于Q-R矩阵分解的自适应卡尔曼滤波算法。将协方差阵分解为两个矩阵的乘积,来保证协方差矩阵的正定性。仿真结果表明,该算法可以较好地跟踪机动目标,具有精度高、稳定好、收敛快等特点。     

强实时双系统中容错技术研究

在关键任务部门中 ,实时双系统的应用越来越广泛。如何保证高的可用度和高的响应时间是它们共同面临的问题。在本文中 ,全面论述了强实时双系统容错技术中的关键问题 ,包括系统结构定义、故障检测、状态切换。实际应用的结果表明 ,方案可以满足应用系统高可靠、强实时的需求 ,取得了良好的效果     

给定任务和模式下指挥体系节点重要性评估方法

针对一般节点重要度评估方法没有考虑指挥体系网络与外界的交互以及自身运行机制的问题,研究了指挥节点的重要度评估方法,在一般网络结构重要度分析基础上,综合作战任务和指挥模式对节点的需求,提出了作战任务对节点依赖度以及指挥模式对节点依赖度的计算方法,最后设计了评估算法并给出具体算法流程,案例分析结果证明该算法合理、有效。     

舰艇编队海上运输补给物资需求预测方法

按照是否与任务、事件相关,将物资需求分为两类,对于任务、事件相关物资需求的预测,将任务进行合理的分解,并根据物资消耗与任务、事件之间的关系,给出了预测的一般模型;对于与任务、事件联系不紧密的物资需求的预测,则根据历史经验及该物资固有的消耗规律,提出了经验预测模型。为了解决舰艇编队海上运输补给物资需求预测所存在的问题,利用案例推理的方法生成了预测所需的样本数据,以最小二乘向量机(LSSVM)模型为预测模型,并以岛屿进攻作战的防空弹药需求预测为例进行了实例分析。结果表明:案例推理生成的样本数据可用,选用LSSVM模型的预测结果与其他预测模型表现出了一致性,但LSSVM相对误差较小;该方法在某种程度上解决了样本数据有限的问题,适用于作战物资需求的预测问题。     

S弯进气道合成双射流流场控制特性分析

针对飞翼布局无人飞行器中S弯进气道明显流动分离和出口总压畸变等问题,提出了基于合成双射流的主动流动控制方法,建立了合成双射流的S弯进气道数值仿真模型。结果表明,在S弯进气道分离点附近施加合成双射流控制,在整个射流周期内通过“吹”“吸”接力可以有效抑制边界层流动分离,有效提升总压恢复系数。对比研究了合成双射流不同射流角度、射流峰值速度和激励频率对S弯进气道流场控制特性的影响规律。结果表明合成双射流与主流的角度越小,流动分离控制效果越好,较大射流峰值速度会对主流形成“阻挡”致使控制效果下降,激励频率与流场特征频率越接近控制效果越明显。     

Preparation of ammonium nitrate-based solid composite propellants supplemented with polyurethane/nitrocellulose blends binder and their thermal decomposition behavior

To improve the performance of solid composite propellants (SCPs) supplemented with ammonium nitrate (AN) as an oxidizer, the incorporation of energetic ingredients such as explosives, energetic binders or catalysts is a common effective approach. For this purpose, polyurethane (PU), a typical inert binder, was mixed with nitrocellulose (NC) as an energetic polymer. Numerous composite solid propellant compositions based on AN and NC-modified polyurethane binder with different NC ratios were prepared. The prepared formulations were characterized using Fourier transform infrared spectroscopy (FTIR), RAMAN spectroscopy, X-ray diffraction (XRD), electron densimetry, thermogravimetric (TG) analysis, and differential scanning calorimetry (DSC). A kinetic study was then performed using the iterative Kissinger-Akahira-Sunose (It-KAS), Flynn-Wall-Ozawa (It-FWO), and non-linear Vyazovkin integral with compensation effect (VYA/CE) methods. The theoretical performances, such as theoretical specific impulse, adiabatic flame temperature, and ideal exhaust gaseous species, were also determined using the NASA Lewis Code, Chemical Equilibrium with Application (CEA). Spectroscopic examinations revealed the existence of NC and full polymerization of PU in the prepared propellants. According to density tests, the density of the propellant increases as the nitrocellulose component increases. According to the thermal analysis and kinetics study, the increase in NC content catalyzed the thermal decomposition of the AN-based composite solid propellants. Based on the theoretical study, increasing the amount of NC in the propellant increased the specific impulse and, as a result, the overall performance.     

一种新的基于特征值分解的双站无源定位算法

在自卫式噪声干扰的条件下,地面制导雷达将无法得到目标的斜距信息,无法实现对目标的定位,此时只有采用雷达组网方式,利用2个或多个雷达站的测角信息来对空间目标进行定位。提出一种基于特征值分解的新的定位跟踪算法,该算法具有计算简单、清晰,运算量小的优点,仿真也表明该算法有较好的精度。     

The effect of al particle size on thermal decomposition,mechanical strength and sensitivity of Al/ZrH2/PTFE composite

To study the thermal decomposition of Al/ZrH2/PTFE with different Al particle size as well as mechanical strength and impact sensitivity under medium and low strain rates, molding-vacuum sintering was adopted to prepare four groups of power materials and cylindrical specimens with different Al particle size. The active decomposition temperature of ZrH2 was obtained by TG-DSC, and the quasi-static me-chanics/reaction characteristics as well as the impact sensitivity of the specimen were studied respec-tively by quasi-static compression and drop-hammer test. The results show that the yield strength of the material decreased with the increase of the Al particle size, while the compressive strength, failure strain and toughness increased first and then decreased, which reached the maximum values of 116.61 MPa, 191％, and 119.9 MJ/m respectively when the Al particle size is 12—14μm because of particle size grading. The specimens with the highest strength and toughness formed circumferential open cracks and reacted partly when pressed. Those with developmental cracks formed inside did not react. It is considered that fracture of specimens first triggered initial reaction between Al and PTFE to release an amount of heat. Then ZrH2 was activated and decomposed, and participated in subsequent reaction to generate ZrC. The impact sensitivity of the specimens decreased with the increase of Al particle size.