Optimal midcourse trajectory cluster generation and trajectory modification for hypersonic interceptions

The hypersonic interception in near space is a great challenge because of the target’s unpredictable trajectory, which demands the interceptors of trajectory cluster coverage of the predicted area and optimal trajectory modification capability aiming at the consistently updating predicted impact point(PIP) in the midcourse phase. A novel midcourse optimal trajectory cluster generation and trajectory modification algorithm is proposed based on the neighboring optimal control theory. Firstly, the midcourse trajectory optimization problem is introduced; the necessary conditions for the optimal control and the transversality constraints are given.Secondly, with the description of the neighboring optimal trajectory existence theory(NOTET), the neighboring optimal control(NOC)algorithm is derived by taking the second order partial derivations with the necessary conditions and transversality conditions. The revised terminal constraints are reversely integrated to the initial time and the perturbations of the co-states are further expressed with the states deviations and terminal constraints modifications.Thirdly, the simulations of two different scenarios are carried out and the results prove the effectiveness and optimality of the proposed method.

Optimal midcourse trajectory planning considering the capture region

An optimal midcourse trajectory planning approach that considers the capture region（CR） of the terminal guidance is proposed in this article based on the Gauss pseudospectral method（GPM）. Firstly, the planar CR of the proportional navigation in terminal guidance is analyzed and innovatively introduced in the midcourse trajectory planning problems, with the collision triangle（CT） serving as the ideal terminal states parameters of the midcourse phase, and the CR area serving as the robustness against target maneuvers. Secondly, the midcourse trajectory planning problem that considers the path, terminal and control constraints is formulated and the well-developed GPM is used to generate the nominal trajectory that meets the CR demands. The interceptor will reshape the trajectory only when the former CR fails to cover the target, which has loosened the critical demand for frequent trajectory modification. Finally, the simulations of four different scenarios are carried out and the results prove the effectiveness and optimality of the proposed method.

Aero-thermal heating constrained midcourse guidance using state-constrained model predictive static programming method

This paper proposes a multiple-constraints-guaranteed midcourse guidance law for the interception of the hypersonic targets. In traditional midcourse law design, the constraints of the aero-thermal heating are rarely taken into consideration. The performance of the infrared detection system may be degraded and the instability of the flight control system may be induced.To address this problem, a state-constrained model predictive static programming method is introduced such that both terminal constraints(position and angle) and optimal energy consumption can be ensured. As a result, a sub-optimal midcourse guidance,guaranteeing the aforementioned multiple-constraints to be never violated, is synthesized. Simulation results demonstrate the effectiveness of the proposed method.

INVESTIGATION OF TIGHTLY COUPLED SINS/GPS INTEGRATION MIDCOURSE GUIDANCE FOR AIR-TO-AIR MISSILES

The applied problems of SINS/GPS integration navigation system existing in midcourse guidance of air to air missiles have been investigated recently. In comparison with those investigations existing in current publications, a new tightly coupled SINS/GPS integration navigation system for air to air missiles, based on the decorrelated pseudo range approach, is presented in this paper. Because of high jamming and dynamic of air to air missiles, inertial velocity aiding GPS receiver is used to provide a more accurate, jam resistant measurement for midcourse guidance systems. A tracking error estimator is designed to distinguish the correlation that existed between pseudo range measurements and inertial information. It is found better to regard inertial velocity aiding errors as the noise of which statistical properties are unknown. So using mixed Kalman/minimax filtering theory, one can obtain the new tracking error estimator with simple and robust algorithm through constructing a composite filter consisting of two parts: Kalman filter for the noise of known statistics and minimax filter for the unknown. In order to ensure this simple estimator stability, a new method is proposed to choose its parameters, based on Khargonekars work. Moreover, it is demonstrated that the given method also ensures the proposed estimator optimality. All the work mentioned above is involved in the tightly coupled SINS/GPS integration midcourse system design in which a set of low accuracy inertial components is shared by SINS and autopilot. Simulation results of a certain type of air to air missile are presented. Due to decorrelation by the tracking error estimator, only small white noise of pseudo range measurements remains. So it is shown that application of the new midcourse guidance system results in better guidance accuracy, higher jam resistance.

红外预警机对弹道导弹中段弹头探测能力研究

文中着眼发挥预警机的灵活性、拓展弹道导弹防御层次,对红外预警机探测弹道导弹中段弹头的能力进行研究。从红外传感器作用距离影响因素入手分析了中段弹头红外辐射特性及其红外背景,借助大气传输软件MODTRAN分析了大气透过率随观测天顶角的变化情况,进而建立了机载红外传感器对中段弹头的最大作用距离模型。结合弹道导弹运动特性分析了地球曲率、预警机与目标直线距离等条件对探测能力的约束,以2500km射程导弹为例仿真分析了预警机不同配置位置下对中段弹头的探测能力,所得结论可为弹道导弹防御作战中预警兵力配置提供参考。

导弹突防后弹道机动调整策略强化学习

针对弹道导弹中段突防后飞行弹道与标准弹道产生较大偏离的弹道机动调整问题,建立了机动调整时机策略最优化模型。设计了机动调整逆序Q学习算法,采用Tile coding逼近器编码状态特征空间,并对其进行线性逼近。构建了Q学习算法与蒙特卡罗方法相结合的逆序更新策略机制,以对导弹机动调整最优时机进行训练。仿真测试分析结果表明,在给定场景参数下,通过10000代强化学习算法训练得到的策略能够可靠地使用最少机动次数控制导弹突防后飞行弹道的调整决策,验证了方法的有效性。

基于动力学守恒定律的弹道目标关联方法

中段伴飞突防造成的各种有源或无源的弹道群目标会给雷达跟踪系统带来极大的挑战,导致其跟踪非本体实体目标或电假目标,从而出现关联错误的情况。中段实体弹道目标满足动力学守恒定律,可以充分利用该特性来改善跟踪系统的数据关联机制,因此提出一种基于动力学守恒定律的弹道目标概率数据关联(probability data association,PDA)方法,即在传统关联门筛选出有效量测的基础上,对动量矩和机械能进行联合统计检验,进一步剔除电假目标点迹或其他错误量测,并使用动量矩和机械能对加权关联概率进行修正。蒙特卡罗仿真验证了该方法的有效性。仿真结果表明,与传统PDA方法相比,所提方法能够有效抑制有源距离欺骗干扰和杂波的影响,提高跟踪精度。

上升段气动加热对飞行中段高速飞行器红外辐射特性影响分析

飞行中段高速飞行器红外辐射特性是对其进行红外探测、识别及跟踪的基础。飞行中段高速飞行器红外辐射与表面温度密切相关,而飞行器表面温度又与上升段气动加热、空间环境热辐射、防热材料结构等有关,特别是上升段气动加热对飞行中段飞行器红外辐射的影响不容忽视。为获得复杂环境背景下高速飞行器在飞行中段的红外辐射,综合考虑上升段气动加热、环境辐射加热、表面辐射散热和结构热传导等主要因素影响,采用气动热工程计算模型、空间辐射加热、一维多层热传导计算方法,建立了高速飞行器红外辐射分析技术,实现了气动加热、环境辐射加热、自身辐射散热、结构热传导等多种主要因素影响下的高速飞行器飞行中段温度场和红外辐射分析。结果表明:上升段的气动加热会对飞行中段的高速飞行器红外辐射产生较大影响;在飞行中段,飞行器在长波8~12μm波段的红外辐射强度明显大于在中波3~5μm波段的红外辐射强度,选择8~12μm波段更有利于对飞行中段高速飞行器的探测。

基于序列凸规划的拦截弹中制导轨迹优化

针对强非线性多约束条件下拦截弹中制导轨迹优化问题,基于序列凸规划方法和捕获区域,提出一种针对固定时间约束下的轨迹优化算法。序列凸优化方法求解复杂多项式具有高效的计算效率,但在轨迹优化问题中应用序列凸规划有控制变量的强非线性和固定时间内终端约束难以收敛两大难点。首先,采用仿射变量将问题转化为仿射系统,并将仿射系统进行凸化与离散化,来解决非线性问题,然后,提出一种终端约束加权松弛化方法来解决固定时间内终端约束难以收敛问题,并将中制导问题转化为序列凸规划问题。仿真结果表明,所提算法能较快地生成符合多约束条件的拦截弹中制导轨迹。

美国陆基中段防御核心能力分析评估

基于美国陆基中段防御系统发展情况与公开情报信息,结合美国弹道导弹防御工业基础与技术水平,运用系统工程方法,对其预警与跟踪识别能力、保护区、导弹单发杀伤概率、多目标能力、对付目标能力水平5项核心能力进行了定量分析或定性评估,有助于更深入准确地认识美国陆基中段防御能力。

美国陆基中段防御威胁控制区解析

基于美国陆基中段防御系统公开情报信息与性能参数,提出一种弹道导弹防御威胁控制区分析方法,建立美国陆基中段防御威胁控制区分析模型,并对GBI飞行中保持与基地视距通信、有多点IDT充分支持2种情况下美国陆基中段防御的威胁控制区进行了仿真分析,有助于更深入准确地认识美国陆基中段防御能力。

基于零控脱靶量的大气层外拦截中制导方法研究

针对大气层外拦截器在中制导结束后还需要长时间无控飞行的情况,基于零控脱靶量思想采用最优控制理论,对拦截器和目标的相对运动关系进行了理论推导,以脱靶量和中制导加速度为性能指标,设计了一种拦截器发动机固定推进时间的中制导策略,研究了拦截器制导精度与零控脱靶量预测精度的关系,提出了调节拦截器机动过载大小的实现途径。仿真结果表明,设计的中制导律精度高、可靠性好、形式简单,在脱靶量计算得足够精确时,中制导结束后的零控脱靶量可控制在百米量级内,为拦截器以动能碰撞方式拦截目标创造了优良的末制导条件。

利用低数据率HRRP序列进行弹道中段目标识别

雷达目标识别是弹道防御阶段的关键环节,为节约雷达时间资源和降低对计算机处理能力的要求,需研究低数据率雷达回波信号的弹道中段目标识别方法,本文以低数据率目标高分辨一维距离像序列(High Resolution Range Profile,HRRP)为研究对象,提出了基于图像投影法的进动频率特征提取算法和基于特征级融合的弹道中段目标识别方法,解决了由于HRRP回波序列数据率过低而导致的时频曲线周期模糊和单一特征造成目标识别准确率浮动大的问题。本文通过仿真弹道导弹中段飞行场景中弹头、重诱饵、轻诱饵、碎片目标的特性数据,同时考虑目标尺寸、形状和微运动模型等差异,结合仿真数据对本文所提算法进行验证。实验结果表明在低数据率(10~100 Hz)下,HRRP序列利用本文算法提取的进动频率特征结果误差值小于0.05 Hz,具有较高准确性和稳定性,通过特征融合方法联合进动频率和目标结构特征将弹道中段目标的识别准确率提升到了96%以上且趋于稳定。

Discussion on neighborhood optimal trajectory online correction algorithm and its application range

This paper presents a neighborhood optimal trajectory online correction algorithm considering terminal time variation,and investigates its application range.Firstly,the motion model of midcourse guidance is established,and the online trajectory correction-regenerating strategy is introduced.Secondly,based on the neighborhood optimal control theory,a neighborhood optimal trajectory online correction algorithm considering the terminal time variation is proposed by adding the consideration of terminal time variation to the traditional neighborhood optimal trajectory correction method.Thirdly,the Monte Carlo simulation method is used to analyze the application range of the algorithm,which provides a basis for the division of application domain of the online correction algorithm and the online regeneration algorithm of midcourse guidance trajectory.Finally,the simulation results show that the algorithm has high real-time performance,and the online correction trajectory can meet the requirements of terminal constraint change.The application range of the algorithm is obtained through Monte Carlo simulation.

Midcourse correction of Earth-Moon distant retrograde orbit transfer trajectories based on high-order state transition tensors

Midcourse correction design is key to space transfers in the cislunar space.Autonomous guidance has garnered significant attention for its promise to decrease the dependence on ground control systems.This study addresses the problem of midcourse corrections for Earth-Moon transfer orbits based on high-order state transition tensors(STTs).The scenarios considered are direct Earth-Moon transfers and low-energy transfers to lunar distant retrograde orbits(DROs),where the latter involve weak stability boundary(WSB)and lunar gravity assist(LGA)techniques.Semi-analytical formulas are provided for computing the trajectory correction maneuvers(TCMs)using high-order STTs derived using the differential algebraic method.Monte Carlo simulations are performed to evaluate the effectiveness of the proposed approach.Compared with existing explicit guidance algorithms,the STT-based approach is much cheaper computationally and features fewer final position errors.These results are promising for fast and efficient orbital autonomous correction guidance approaches in the cislunar space.

多约束条件下多目标反导最优分配策略研究

针对弹道导弹中段拦截问题,研究了多对多场景下的武器-目标最优分配策略。首先,提出了一种拦截弹发射诸元和拦截诸元快速解算方法,并建立了最优分配指标模型,实现了拦截效能和威胁指标的快速求解。由于能够预判弹-目末交战过程,较传统的基于单发拦截概率的方法而言,提出的方法在拦截效能的计算上更具实际意义。其次,提出了一种改进粒子群优化算法,以及一种基于种群平均适应度方差的动态变异策略,通过量化群体进化过程的方式从根本上提升了算法的搜索效率,保证了最优分配策略的快速生成。最后通过仿真计算验证了方法的准确性和可行性。

弹道导弹中段弹头表面温度场分布理论分析

论述了弹道导弹中段弹头表面温度场分布的理论计算方法,采用节点网络法,建立恰当的计算模型,并运用四阶RungeK-utta法求解了热平衡方程组,得出弹头中段任意时刻的温度场分布,最后定量分析了各种因素对弹头温度场分布的影响。

弹道中段目标动态红外辐射特性仿真计算

利用红外光谱辐射特性进行弹道式空间目标探测和识别是一种有效的方法,用该技术探测弹道式空间目标就要对空间目标的红外辐射特性进行研究。在原有目标和诱饵红外辐射特性模型的基础上,综合考虑目标弹道和姿态运动,空间热环境辐射和内热源传热等因素,利用节点网络法建立了弹道中段目标的动态红外辐射计算模型,实现了在不同时刻、不同观测点、不同运动状态下的中段目标红外辐射特性的仿真计算。根据公开的相关资料,设计了两种目标和诱饵,通过对比分析不同弹道条件下目标与诱饵的辐射特性,验证了计算模型的正确性。

弹道中段雷达目标识别仿真系统的关键模型及实现

雷达是弹道中段的主要传感器,在中段目标识别中发挥着核心作用。根据弹道目标雷达识别仿真系统的要求及弹道目标识别的特点,建立了弹道目标雷达特征数据产生、雷达目标识别特征提取、识别算法融合等多个关键模型,设计并实现了弹道中段雷达目标识别仿真系统。进行了典型战情下的雷达目标识别仿真,仿真结果表明所设计的仿真系统稳健可行,系统可以为弹道中段雷达目标识别研究提供仿真支撑。

弹道中段目标RCS周期特性及其估计方法

分析了弹头目标的RCS周期特性,指出了传统频域分析方法的不足,提出了一种新的RCS周期估计方法。通过合成循环平均幅度差函数(CAMDF)和循环自相关函数(CAUTOC),有效克服了传统频域估计方法的不足,且具有优良的抗噪性能。仿真实验结果表明该方法能明显改善RCS周期估计的精确性和稳定性。