基于可达区预测的高速机动目标多弹拦截决策

针对大气层内高速机动目标的多弹拦截问题,提出了一种基于可达区预测的多弹拦截决策方法。基于机动能力分析与曲线拟合方法建立了拦截弹可达区的解析模型,可实现在给定发射点与预测命中点后拦截弹可达区边界生成;结合进攻弹的可达区快速预测方法,将高速机动目标的多弹拦截决策转化为攻防可达区覆盖优化问题,设计寻优算法并求解得到使用最少拦截弹覆盖最大范围进攻弹可达区的多弹拦截策略;通过数值仿真验证了所提方法的有效性。

交会与拦截动力学内涵探讨

交会与拦截是动力学中的两个典型应用场景,都是研究空间中两个运动质点的精确相对运动的问题。传统的课程教学忽视了两者的内在联系,教学内容存在交叉重复、不统一等问题,本文以理论力学中点的复合运动为基础,从动力学模型与制导律两个维度对交会和拦截的内涵关系进行深度挖掘和阐释,打通两类相对运动之间的壁垒,建立起教学内容的有效链接,探索了航天动力学教学的新框架,有助于提升教学效率。

海南古代医药卫生类文献的收集与整理

基于文献调研、收集与整理的成果,探讨了海南古代医药卫生类文献的内涵、外延,分析了其在时间、体裁、内容、馆藏上的分布及相关特征,并以与医药卫生有关的特产药材、医学教育、卫生行政、流行病疫情、医学人物、医学著作等内容为类别,分述了相关古代文献收集、整理的标准、方法、体例及成果概况。

基于改进GoogLeNet的锌渣识别算法

针对目前热镀锌工艺中捞渣机器人工作效率低、缺乏选择性等问题,提出一种基于深度学习的锌渣识别算法,以提高捞渣生产线无人化水平。首先,在GoogLeNet网络基础上进行改进,并搭建了适用于实际生产环境的锌渣识别模型;其次,利用经验丰富的工作人员所标注的薄渣和厚渣这两类锌渣图片来建立数据库,完成锌渣分类模型的训练;最后,将工业相机采集到的锌渣图像进行分块处理,标记每张小图的位置,将分割后的小图输入到训练好的模型中完成分类,并得到待捞锌渣的位置。实验结果显示,本文方法在测试集上的识别准确率达到99.1%,高于对比算法,并且针对每张锌渣原始图像的平均识别时间为0.36 s,只有传统GoogLeNet模型的53%,这证明所提出的锌渣识别算法具有较好的工业应用前景。

纯比例导引律解析解与三维碰撞角约束制导

为提高空地导弹碰撞角约束制导的精度和鲁棒性,增强其对防空系统的突防能力和对目标的打击效果,基于纯比例导引律(pure proportional navigation,PPN)拦截固定目标的解析解,提出了一种新的三维碰撞角约束制导律(three-dimensional PPN-based impact-angle-control guidance law,3D-PPNIACG)。首先,基于PPN拦截固定目标解析解,分析了基于PPN的二维碰撞角约束制导律(two-dimensional PPN-based impact angle constraint guidance law,2D-PPNIACG)的拦截制导性能,包括最大过载、能量消耗与捕获区域。其次,基于2D-PPNIACG和三维拦截制导的垂直分解方法,结合对空间几何关系的深入分析,提出了控制铅垂面内落角和水平面内碰撞角的三维碰撞角约束制导律(3D-PPNIACG),并对该制导律的实用性和鲁棒性进行了充分讨论。最后通过数值仿真,验证了3D-PPNIACG在碰撞角约束制导中的有效性和鲁棒性。研究和仿真结果表明,所提出的3D-PPNIACG结构简单、易于实现、鲁棒性好,在考虑测量误差、动力学响应延迟等现实因素的情况下,可有效实现水平面内的碰撞角约束制导和铅垂面内的落角约束制导,具有良好的应用前景。

Review on strategies of space-based optical space situational awareness

Space-based optical(SBO)space surveillance has attracted widespread interest in the last two decades due to its considerable value in space situation awareness(SSA).SBO observation strategy,which is related to the performance of space surveillance,is the top-level design in SSA missions reviewed.The recognized real programs about SBO SAA proposed by the institutions in the U.S.,Canada,Europe,etc.,are summarized firstly,from which an insight of the development trend of SBO SAA can be obtained.According to the aim of the SBO SSA,the missions can be divided into general surveillance and space object tracking.Thus,there are two major categories for SBO SSA strategies.Existing general surveillance strategies for observing low earth orbit(LEO)objects and beyond-LEO objects are summarized and compared in terms of coverage rate,revisit time,visibility period,and image processing.Then,the SBO space object tracking strategies,which has experienced from tracking an object with a single satellite to tracking an object with multiple satellites cooperatively,are also summarized.Finally,this paper looks into the development trend in the future and points out several problems that challenges the SBO SSA.

以c-Met为靶向的抗肿瘤药物研究进展

c-Met蛋白为酪氨酸蛋白激酶,又称肝细胞生长因子(HGF)受体。c-Met在许多肿瘤中被高效表达并有效激活,在各种肿瘤的病程进展中发挥着关键作用。本文对c-Met的分子结构、信号通路、靶向药物治疗和相关药物专利进行综述。

基于最优误差动力学的变速导弹飞行路程控制制导律

针对基于常速假设的飞行时间控制制导律在实际应用中存在性能下降的问题,将飞行时间控制问题转化为飞行路程控制问题,提出一种适用于变速导弹的飞行路程控制制导方案。首先,基于古典微分几何曲线原理构建弧长域内导弹打击固定目标的相对运动方程,消除了导弹速度大小变化的影响。其次,基于高斯超几何函数,推导了纯比例导引律制导下变速导弹对固定目标的剩余飞行路程精确解。然后,进一步基于最优误差动力学方法,在不考虑小角假设和其他近似假设的前提下,设计了变速导弹全局非线性飞行路程控制制导律。最后,通过数值仿真验证了所提方法的有效性。

基于PSO和RRT的智能弹群任务分配算法

设计新的粒子群(PSO)算法的粒子结构,以解决智能弹群任务分配问题。首先,引入战场态势信息以确定智能弹群任务时间窗口,并将其融入任务分配数学模型。其次,基于快速搜索随机树(RRT)算法,在任务分配阶段完成躲避禁飞区的航迹规划,以减小实际航程与预估航程之间的差异,确保分配结果的合理性,使优化结果更具实际意义。最后,在不同任务规模下将所提出的算法与遗传算法和禁忌搜索算法结果进行仿真对比分析,所得结果验证了本文方法的原理简单、参数较少、计算代价小、更易于智能弹群任务分配问题的实际工程应用。

基于误差动力学的全局非线性精确飞行时间控制制导律设计

针对当前飞行时间控制制导律在大前置角场景中存在失效风险的问题,本文提出了一种基于误差动力学原理的全局非线性精确飞行时间控制制导律设计方法.首先基于导弹非线性制导模型,利用高斯超几何函数方法推导了比例导引律导引的导弹剩余飞行时间精确解和级数解.在此基础上,将基于误差动力学原理的制导律设计方法拓展到大前置角场景中,推导了精确剩余飞行时间误差动力学方程,利用剩余飞行时间精确解分别给出了基于最优误差动力学和固定时间收敛误差动力学的精确飞行时间控制制导律,最后通过仿真验证了所设计制导律的优越性.

基于纯比例导引的拦截碰撞角约束制导策略

拦截碰撞角约束制导是当前导弹制导研究的关键问题之一。首先基于理想比例导引(IPN)律拦截非机动目标的解析解,推导了纯比例导引律(PPN)拦截固定目标的解析解,得到了弹目相对距离、制导指令加速度和导弹前置角的显示表达式,并进一步得到了拦截碰撞角与弹目相对运动状态和比例导引系数之间的解析表达式。其次,基于该解析表达式,提出了基于PPN的拦截碰撞角约束制导策略(PPNIACG),并探讨了在铅垂面内进行落角约束打击和水平面内进行拦截碰撞角约束打击的2种实现方式。最后,以弹道成型制导律(TSG)和最优碰撞角约束制导律(OIACG)为参考,通过数值仿真算例,对PPNIAC的拦截性能进行了对比分析,验证了所提出制导策略的有效性和正确性。

面向空间态势感知的天基可见光空间目标自主跟踪方法

天基可见光(space-based optical,SBO)监视是空间态势感知的重要手段之一.传统的天基观测平台都需要在自身精密星历已知的情况下,通过对目标的测量,确定其状态.而本文提出了自主天基空间目标监视的概念,天基可见光观测平台在自身精密星历未知时,也可以完成空间态势感知任务.与传统的目标跟踪不同,此方法只需依靠平台获取的在惯性系下描述的仅测角测量信息,便可实现自主定轨.结合长弧段的观测数据,本文给出了基于历史数据的事后自主轨道改进算法.通过分析发现,观测卫星对其他目标观测的历史数据也可用于改进原有的被观测目标的轨道.基于此,本文提出了通过额外测量量辅助下的实时自主跟踪策略,可通过单星搭载多SBO相机,对多目标同时跟踪的方式实现.最后,本文通过仿真算例验证了所提出方法的可行性.与传统的空间目标跟踪相比,虽然自主跟踪的精度较低,但在同时跟踪两目标时,尤其是在同时跟踪低轨和高轨两目标的情况下,估计精度能接近传统方法的水平.本文为发展自主天基空间态势感知平台提供了可行的方法.

现实真比例导引拦截任意机动目标捕获区域

主动机动突防技术的发展给大气层外动能拦截带来了严重困难。假设目标机动加速度方向垂直于弹目视线、形式任意且有界,分析了用于大气层外拦截制导的现实真比例导引律(RTPN)对该任意机动目标的捕获区域。首先在考虑拦截器存在机动过载饱和限制的情况下,推导了比例导引系数的选择范围,可使RTPN的制导指令加速度在拦截过程中不超过拦截器饱和过载;其次基于不等式分析方法,在不考虑拦截器过载限制时,推导了RTPN对任意机动目标的捕获区域;然后结合拦截器机动过载限制,推导了RTPN对任意机动目标的更加实用的捕获区域;最后通过数值仿真算例,验证了所提出的理论。

Improved differential geometric guidance commands for endoatmospheric interception of high-speed targets

Pure proportional navigation(PPN) is suitable for endoatmospheric interceptions,for its commanded acceleration is perpendicular to interceptor velocity.However,if the target is much faster than the interceptor,the homing performance of PPN will be degraded badly.True proportional navigation(TPN) does not have this problem,but its commanded acceleration is perpendicular to the line of sight(LOS),which is not suitable for endoatmospheric interceptions.The commanded acceleration of differential geometric guidance commands(DGGC) is perpendicular to the interceptor velocity,while the homing performance approximates the LOS referenced guidance laws(PPN series).Therefore,DGGC is suitable for endoatmospheric interception of high-speed targets.However,target maneuver information is essential for the construction of DGGC,and the guidance commands are complex and may be without robustness.Through the deep analysis of three-dimensional engagement,a new construction method of DGGC is proposed in this paper.The target maneuver information is not needed any more,and the robustness of DGGC is guaranteed,which makes the application of DGGC possible.

Algebraic solution of differential geometric guidance command and time delay control

According to the three-dimensional geometry of the engagement,the explicit algebraic expression of differential geometric guidance command(DGGC)is proposed.Compared with the existing solutions,the algebraic solution is much simpler and better for the further research of the characteristics of DGGC.Time delay control(TDC)is a useful method to tackle the uncertainty problem of a control system.Based on TDC,taking the target maneuvering acceleration as a disturbance,the estimation algorithm of the target maneuvering acceleration is presented,which can be introduced in DGGC to improve its performance.Then,the augmented DGGC(ADGGC)is obtained.The numerical simulation of intercepting a high maneuvering target is conducted to demonstrate the effectiveness of ADGGC.

Performance of 3D TPN against true-arbitrarily maneuvering target for exoatmospheric interception

True proportional navigation(TPN) guidance law is widely used for exoatmospheric interception, for its robustness and ease of implementation. The performance of TPN against nonmaneuvering target or the maneuvering target with a specific acceleration had been analyzed before. However, the obtained results are not suitable for the realistic exoatmospheric interception scenario,since the target may maneuver along an arbitrary direction with an arbitrary but upper-bounded acceleration in the threedimensional(3 D) space, which is the so-called "true-arbitrarily maneuvering target" in this paper. With the help of the line-ofsight(LOS) rotation coordinate system, the performance of 3 D TPN against the true-arbitrarily maneuvering target is thoroughly analyzed using the Lyapunov-like approach. The upper-bound of the 3 D LOS rate is obtained, and so is that of the commanded acceleration of 3 D TPN. After that, the capture region of 3 D TPN is presented on the initial relative velocity plane. The nonlinear3 D relative kinematics between the interceptor and the target is taken into full account. Finally, the new theoretical findings are demonstrated by numerical simulations.

A novel biased proportional navigation guidance law for close approach phase

A novel biased proportional navigation guidance （BPNG） law is proposed for the close approach phase, which aims to make the spacecraft rendezvous with the target in specific relative range and direction. Firstly, in order to describe the special guidance requirements, the concept of zero effort miss vector is proposed and the dangerous area where there exists collision risk for safety consideration is defined. Secondly, the BPNG, which decouples the range control and direc- tion control, is designed in the line-of-sight （LOS） rotation coordinate system. The theoretical anal- ysis proves that BPNG meets guidance requirements quite well. Thirdly, for the consideration of fuel consumption, the optimal biased proportional navigation guidance （OBPNG） law is derived by solving the Schwartz inequality. Finally, simulation results show that BPNG is effective for the close approach with the ability of evading the dangerous area and OBPNG consumes less fuel compared with BPNG.

Ideal proportional navigation for exoatmospheric interception

Ideal proportional navigation （IPN） is a natural choice for exoatmospheric interception for its mighty capture capability and ease of implementation. The closed-form solution of two- dimensional ideal proportional navigation was conducted in previous public literature, whereas the practical interception happens in the three-dimensional space. A novel set of relative dynamic equations is adopted in this paper, which is with the advantage of decoupling relative motion in the instantaneous rotation plane of the line of sight from the rotation of this plane. The dimension-reduced IPN is constructed in this instantaneous plane, which functions as a three-dimensional guidance law. The trajectory features of dimension-reduced IPN are explored, and the capture regions of dimension-reduced IPN with limited acceleration against nonmaneuvering and maneuvering targets are analyzed by using phase plane method. It is proved that the capture capability of IPN is much stronger than true proportional navigation （TPN）, no matter the target maneuvers or not. Finally, simulation results indicate that IPN is more effective than TPN in exoatmospheric interception scenarios.

Impact Angle/Time Constraint Guidance Design Based on Fast Terminal Error Dynamics

Considering the problem that the optimal error dynamics can only converge at the terminal time,an impact angle/time constraint missile guidance law with finite-time convergence is designed in this paper,which is based on the pure proportional navigation(PPN)guidance law and the fast terminal error dynamics(FTED)approach.The missile guidance model and FTED equation are given first,and the dynamic equation of impact angle/time error based on PPN is also derived.Then,the guidance law is designed based on FTED,and the guidance error can converge to 0 in a finite time.Furthermore,considering the field of view constraint,the guidance law is improved by using the saturation function mapping method.Finally,a numerical simulation example is given to verify the effectiveness of the guidance law,which shows that the guidance law proposed in this paper can make the missile quickly adjust to the desired states in advance,and effectively relieve the overload saturation pressure of the actuator.