Variable Structure Proportional Navigation for Homing Missile

The purpose of this paper is to design control loop and guidance loop for the homing missile, to prove that the modified variable structure proportional navigation (VSPN) can be used in passive homing guidance system, and to compare the VSPN with the proportional navigation (PN). Angular rate and linear acceleration are fed back to improve the stability and robust of autopilot, VSPN and PN are compared in mathematics simulation of homing missile in attacking tanks and helicopters. The damp and the stability of the missile body are increased. The VSPN cuts down the overload of guidance phase dramatically, makes the ballistic trajectory straighter than PN and leads to smaller missdistance. The VSPN can be used for passive homing guidance system, and is especially suitable for attacking helicopter.

Combined proportional navigation law for interception of high-speed targets

A new proportional navigation(PN) guidance law,called combined proportional navigation(CPN),is proposed.The guidance law is designed to intercept high-speed targets,which is a common case for ballistic targets.The range of target-to-interceptor speed ratio during target interception is derived when guidance laws are applied in high-speed targets interception,and the effectiveness of negative navigation ratio in the PN-based guidance law is proven analytically in some lemmas.Based on the lemmas,the lateral acceleration command of CPN is defined,and the solution to the appearance of singularity in time-varying navigation ratio is given.The simulation results show that CPN can determine headon engagement(as PN) or tail-chase engagement(as RPN) through initial path angle compared with PN and retro proportional navigation(RPN),and can adjust the value of navigation ratio for head-on engagement or tail-chase engagement.Therefore,the capture region of CPN is larger than that of other guidance laws using PN-based methods.

Improved bias proportional navigation with multiple constraints for guide ammunition

According to the infrared guidance ammunition(GA)attacking non-maneuvering targets on the ground or sea level,an improved bias proportional navigation(IBPN) is put forward,which can meet the constraints of the impact angle and the angle of attack(AOA). The motion equations and the collision triangle for the GA and the target are established in the two-dimensional plane. In accordance with the collision triangle, the integral value of the bias term is solved and BPN is designed on the basis of the relative velocity. To ensure the new method can be solved, closedloop equation of the IBPN is deduced. Considering the limitation of the AOA and the seeker angle, a four-phase IBPN is improved by setting different phases of the bias term. At the same time, the guidance law will make the impact angle achieve the desired angle and the normal acceleration also converges to zero. The simulation results show that the improved guidance law can be applied to various flight tasks and has great potential for engineering applications.

Proportional Navigation Guidance Law with Variable Coefficient Gravity Compensation

Based upon a discussion on the merits and limitations of proportional navigation（PN）guidance law in which constant gravity compensation is included as a part,a counterpart having varying compensations,which changes with pitching angle and line-of-sight angle,is substituted.Flight trajectory simulation over a submissile model is conducted,resulting in increased impact angle,shorter miss distance,smaller maximum normal overload and narrower terminal angle of attack.

Biased retro-proportional navigation law for interception of high-speed targets with angular constraint

A new guidance law, called biased retro proportional navigation(BRPN), is proposed. The guidance law is designed to intercept high-speed targets with angular constraint, which can be used for ballistic target interception. BRPN guidance law is defined, and the exact time-varying bias for a required impact angle is derived. Furthermore, the simulation results(trajectory, variation of navigation ratio, capture region, etc) are compared with those of biased proportional navigation(BPN), proportional navigation and retro-proportional navigation. The results show that,at the cost of a higher intercept time, BRPN demands lower terminal lateral acceleration and has larger capture region compared to BPN.

Realization of proportional navigation and lateral acceleration autopilot for endoatmospheric kinetic interceptor with pulse thrusters

The guidance and control strategy for endoatmospheric kinetic interceptor controlled by lateral pulse thrusters was detailed.The pulse thruster control system was firstly proposed.The sample-and-hold approach was introduced to design a novel lateral acceleration autopilot on the basis of traditional two-loop topology.Combined with proportional navigation guidance law and the novel autopilot,the overall ballistic trajectory was presented and examined.Simulation results show that the pulse thruster control strategy can greatly improve the control system response speed and the maximal acceleration capability for realizing kinetic kill interception.

基于STM32的智能航行系统设计

为解决航行器智能确定航向并航行的问题,本文采取模块化的思想设计了一款基于STM32的红外导引的智能航行控制系统。该智能航行系统利用红外接收模块进行红外导引信号的接收,采取线性加权法进行航向与导引信号之间的偏离角确定,利用比例-积分-微分(proportion-integration-differentiation,PID)控制算法对控制舵机转角的脉冲宽度调制(pulse width modulation,PWM)信号的占空比进行确定,从而对螺旋桨的转速与舵桨的转角进行可靠控制。根据水池测试结果,该智能航行控制系统能够对红外接收信号进行快速处理,在保持较高航速的条件下进行可靠的航行控制。

基于协同滤波轨迹预测的机动目标RTPN拦截制导律

针对当前空中威胁目标拦截的实际需求,结合拦截器本身的机动能力,基于全覆盖协同策略,提出一种协同探测的现实真比例导引律(RTPN)制导拦截方法。所提方法解决了传统RTPN方法未考虑拦截器饱和过载限制及对任意机动目标捕获区域的确定问题。此外,针对拦截过程中对目标运动轨迹测量误差及协同探测数据丢包所引起的数据融合精度和鲁棒性问题,提出一种分布式协同滤波算法;针对数据传输和拦截器本身动力学响应延迟等问题,提出一种航迹预测算法。仿真结果验证所提方法能够有效解决饱和过载下的捕获区域确定及动力学延迟问题,及协同探测数据融合中数据丢包所引起的鲁棒性和精度问题。

基于粒子群优化的组合导引律模型

针对导弹打击机动目标的问题,提出了一种基于组合导引律的粒子群优化算法以应对战场环境中的机动目标打击问题。首先对三维弹目运动关系进行分析,设计了一种包含角度和时间偏置项的比例导引律,旨在有效抑制终端角度变化,同时确保打击时间的精确控制。为实现最优导引律参数的求解,研究构建了以打击角、打击时间、法向加速度和脱靶量等约束条件为基础的代价函数。采用标准粒子群算法进行自适应寻优,通过迭代计算确定使代价函数最小化的最优导引律参数,进而得到满足约束条件的最优弹道。为验证算法的有效性,设置了机动目标场景,并设计了与原始比例导引律的对比仿真实验以及多种打击时间测试实验。实验结果表明,相较于传统比例导引律,基于粒子群优化的组合导引律算法在应对机动目标时能够生成满足打击时间要求及其他约束条件的弹道,并在不同打击时间设定下均展现出良好的打击效果,具有广阔的应用前景。

一种基于迁移学习的多任务制导算法

针对典型的飞行器制导任务,利用深度学习算法可以有效地拟合导弹飞行状态与制导指令之间的函数关系。然而当制导任务发生变化时,其二者之间的映射关系也会随之改变,从而导致在当前环境下预训练好的模型无法直接作用于新环境,重新训练制导模型需要大量的弹道数据和巨额的时间成本。为解决上述问题,基于迁移学习的思想引入域对抗神经网络,提出基于迁移学习的多任务制导算法。以1个含有大量标签数据的源域任务辅助2个含有极少量标签数据的目标域任务进行迁移学习,从而克服预训练与在线控制之间的环境差异。使用特征提取器和域判别器提取出对任务环境不敏感的关键特征,使神经网络学习到各个任务所共享的底层信息;为提高预测精度,分别设计针对不同任务的偏置加速度预测器。数值仿真结果表明:基于迁移学习的多任务制导算法实现了导弹在不同任务中的加速度指令预测。

Design and Analysis of Terminal Guidance Law for Kinetic Interceptors based on Pulse Engine

A new terminal guidance law is proposed based on a solid propellant pulse engine and an improved proportional navigation method to address the terminal guidance issue for kinetic interceptors.On this basis,the start-stop curve of the pulse motor during the terminal guidance process is designed,along with its start-up logic.The effectiveness of the proposed guidance strategy is verified through simulation.

Impact time control using biased proportional navigation for missiles with varying velocity

A feasible guidance scheme with impact time constraint is proposed for attacking a stationary target by missiles with time-varying velocity.The main idea is to replace the constant velocity with the future mean velocity;therefore, the existing time-to-go estimation algorithm of the proportional navigation guidance law can be improved to adapt to varying conditions.In order to obtain the prediction of the velocity profile, the velocity differential equation to the downrange is derived, which can be numerically integrated between the current downrange and the target position by the on-board computer.Then, a third-order polynomial is introduced to fit the velocity profile in order to calculate the future mean velocity.At the beginning of each guidance loop, the future mean velocity is predicted and the time-to-go information is updated, based on which a novel biased proportional navigation guidance law is established to achieve the impact time constraint.Finally,numerical simulation results verified the effectiveness of the time-to-go estimation algorithm and the proposed law.

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.

子拦截弹拦截无人机集群防碰撞制导律

为解决子拦截弹拦截无人机集群过程中可能发生的碰撞问题,本文将虚拟排斥力与纯比例导引律结合,提出一种防碰撞纯比例导引制导律(Collision Avoidance-Pure Proportional Guidance Law,CA-PPN)。首先,提出一种子母导弹拦截无人机集群的作战构想,并分析了其中的子拦截弹制导问题。随后,针对子拦截弹制导中可能发生的碰撞问题,在子拦截弹之间设计了一种用于避碰的人工势场,分析了PPN的特性,在此基础上将人工势场下的虚拟排斥力与PPN结合,并加入视场角与过载约束,提出了CA-PPN。仿真结果表明,CA-PPN能在制导子拦截弹有效拦截目标的同时避免相互之间的碰撞。

Cubature Kalman filter with closed-loop covariance feedback control for integrated INS/GNSS navigation

Cubature Kalman Filter(CKF)offers a promising solution to handle the data fusion of integrated nonlinear INS/GNSS(Inertial Navigation System/Global Navigation Satellite System)navigation.However,its accuracy is degraded by inaccurate kinematic noise statistics which originate from disturbances of system dynamics.This paper develops a method of closed-loop feedback covariance control to address the above problem of CKF.In this method,the posterior state and its covariance are fed back to the filtering process to constitute a closed-loop structure for CKF covariance propagation.Subsequently,based on the maximum likelihood principle,a control scheme of the prior state covariance is established by using the feedback state and covariance within an estimation window and further adopting a proportional coefficient to amplify the feedback terms in recent time steps for the full use of new information to reflect actual system characteristics.Since it does not directly use kinematic noise covariance,the proposed method can effectively avoid the adverse impact of inaccurate kinematic noise statistics on filtering solutions.Further,it can also guarantee the prior state covariance to be positive semi-definite without involving extra measures.The efficacy of the proposed method is validated by simulations and experiments for integrated INS/GNSS navigation.

不依赖剩余飞行时间的数据驱动攻击时间控制导引律

针对导弹的攻击时间控制问题,基于比例导引法和数据驱动方法设计出一种不依赖剩余飞行时间信息的两阶段攻击时间控制导引律。第1阶段为攻击时间控制阶段,在比例导引法框架下仿真构建弹道倾角与导弹飞行状态之间的关系数据集,利用神经网络方法离线训练出相应的映射网络模型,根据该映射网络可在导弹飞行过程中实时解算攻击时间对应的理想弹道倾角,导引指令将控制实际弹道倾角收敛至该理想弹道倾角;第2阶段则直接采用比例导引法,最终实现导弹攻击时间控制。不同条件下的仿真结果验证了该导引律的可行性和有效性,与现有同类导引律相比,所设计导引律对攻击时间的控制精度更高、所需控制能量更少。理论分析表明,该导引律可通过更换映射网络推广至攻击角度控制。

应用比例导引法的探测机器人机械臂路径规划

为加快机械臂路径规划速率、提升作业效率,在比例导引法的基础上,提出了探测机器人机械臂路径规划方法。通过RRT算法探索机器人的作业环境,经过滤和分配确定机械臂转动边界点信息;根据机械臂与探测目标间位置关系,计算二者在运动状态下相对距离变化率和视线角变化率,即可得到二者相对运动方程;引入比例导引法,计算探测目标的动态轨迹,在确保机械臂动态跟踪时间和路径最短的前提下,实现目标的探测。实验结果表明,所提方法具有较强的通用性,同时在路径规划和时间成本的控制上也展现出了明显的优势。

阻尼参数连续可调的惯导水平内阻尼方法

针对惯导系统传统阻尼方法存在的阻尼网络设计复杂、状态切换产生较大超调误差等主要问题,提出了一种基于变阻尼比例控制的惯导水平内阻尼方法,在无阻尼惯导东向、北向水平修正回路中增加一条前向比例环节通道,通过合理设计比例参数,利用提取的加速度信息进行惯导水平内阻尼,抑制惯导中舒拉振荡误差。相对于传统阻尼方法,该方法使得阻尼网络设计大为简化。该方法通过连续调整比例控制系数,可实现阻尼系数的连续线性修正,能有效抑制无阻尼状态向阻尼状态切换时超调误差。

拦截高速目标的比例与反比例导引捕获区分析

针对拦截高速目标的作战特点,分析了比例导引(PN)与反比例导引(RPN)的捕获区。首先,通过分析拦截弹与目标的相对运动关系,推导得到了顺轨和逆轨的零控拦截条件,此条件由目标和拦截弹的速度前置角以及二者速度比确定;其次,以拦截弹和目标速度前置角为坐标系,推导得到了PN以及RPN捕获区以及各自导航比设置范围。PN的捕获区由逆轨零控拦截条件以及与其相切且斜率为1/(N-1)的两条直线构成,RPN的捕获区由顺轨零控拦截条件以及与其相切且斜率为1/(-N-1)的两条直线构成;然后,利用函数对称性将PN与RPN捕获区转换到同一坐标区间,得到了相同条件下RPN捕获区要大于PN捕获区的结论;最后,开展了四种情形下的仿真,验证了本文捕获区分析的合理性及有效性。

攻击机动目标的多导弹分布式协同制导律

在分布式通信和增广比例导引的基础上,基于网络同步原理设计了一种多导弹拦截机动目标的分布式协同制导律.该分布式协同制导律由导弹本地导引律和分布式协调策略两部分组成:本地导引律由增广比例导引得到;基于网络同步原理设计了导弹之间的分布式协调策略,实现多弹对机动目标的同时协同攻击.该分布式协同制导律只需要视距内相邻导弹之间传输状态信息,具有通信量小、可扩展性好等特点.仿真结果表明多弹网络系统采用该制导律能够有效地协同攻击机动目标.