带有攻击角度和攻击时间控制的三维制导

 在三维空间导引动力学与运动学模型的基础上,假设目标静止,而导弹本身以恒速运动,根据实际的攻击角度与设定的攻击角度误差,分析和设计了期望的视线（LOS）角运动学,基于李雅普诺夫稳定性理论设计了带有攻击角度控制的三维导弹导引律。为了对攻击时间进行预测与控制,假设导弹本身以恒速或者匀加/减速运动,先将导弹导引到预定的攻击角度上,根据待飞直线距离对待飞时间进行估算,再根据预测时间误差,确定导弹按照特定的圆弧轨迹机动飞行的指令和机动飞行的时间,通过机动飞行来对时间误差进行补偿,最后,再利用所设计的导引律攻击目标。给出了仿真结果。     

一种导弹攻击时间协同导引律

研究了具有攻击时间约束的多枚导弹协同导引律。首先,根据各枚导弹的估计到达时间来指定攻击时间,并由指定攻击时间设计期望的弹目距离,使攻击时间控制问题转化为弹目距离跟踪问题;然后,引入导弹导引非线性模型,采用反馈线性化的方法将其转化为线性模型;最后,利用线性极点配置的方法设计出稳定的控制律。仿真结果证明,所有导弹都能非常精确地按照指定攻击时间到达目标。     

基于轨迹成型的攻击角度与时间控制

假定所成型的导弹飞行轨迹由圆弧段和直线段构成,直线段经过目标点且满足导弹末端攻击角度的要求,圆弧段起始于导弹初始位置且与直线段相切于待定的点,该点由指定的导弹攻击时间通过迭代算法得到。给出了可行的攻击时间范围。在轨迹成型的基础上,提出一种新的虚拟目标轨迹跟踪控制方法：在圆弧段提出一种前馈加反馈的复合控制方案,在直线段提出一种带角度控制的比例导引方案。该方法是一种几何方法,易于工程实施。仿真结果表明,该方法可以有效地同时对攻击角度与攻击时间进行控制。     

基于最优误差动力学的时间角度控制制导律

针对带有攻击时间和终端攻击角度约束的导弹制导问题,设计了一种基于最优误差动力学的时间角度控制制导律,并给出了明确的性能指标。推导广义最优角度控制制导律作用下的剩余飞行时间估算表达式,在广义最优角度控制制导律的基础上增加攻击时间误差反馈项,将攻击时间误差看做跟踪误差,设计的制导律使跟踪误差以最优模式在有限时间内收敛到零,最终实现攻击时间和终端攻击角度的共同控制。对不同参数下的情况进行仿真,验证了所提制导律的有效性。     

Lyapunov-based switched-gain impact angle control guidance

To hit stationary ground targets in specified direction, a nonlinear impact angle control guidance law based on Lyapunov stability theory is proposed. The proposed law ensures the convergence of the heading angle and the miss distance to guarantee a successful engagement. The impact angle can be adjusted by varying a single parameter. And the maximum value of acceleration has been analyzed to get the proper range for control parameter. Considering the achievable impact angle set is limited, an additional phase is added to form a two-phase control strategy. The first phase is to establish a proper initial condition for the second phase, and the second phase is to hit the target with a certain impact angle. An analysis of the proper selection of control parameters to expand the achievable impact angle set is presented. The performance of the proposed guidance law is illustrated with simulations.     

Composite impact vector control based on Apollo descent guidance

A new three-dimensional missile guidance law to control the impact vector against a stationary target is proposed. The composite guidance law has two well-known components: Apollo descent guidance and trajectory shaping guidance. These respectively linear and planar guidance laws are combined to achieve a specified impact direction. The main idea is to define an impact plane and to steer the missile onto this plane using Apollo descent guidance while concurrently performing trajectory shaping wi...     

基于双圆弧原理的协同制导律研究

为了突破舰艇配备的近程防御武器系统,反舰导弹需对攻击时间与攻击角度进行协同制导,以实施饱和攻击。文章基于双圆弧原理提出了一种多导弹攻击时间与攻击角度协同制导律。首先,采用双圆弧原理规划导弹的航路,将导弹导引到预定的攻击角度上。然后,根据待飞直线距离对待飞时间进行估算,求出预测时间误差,确定导弹按照特定的圆弧轨迹机动飞行的指令和机动飞行的时间,通过机动飞行来对时间误差进行补偿。最后,再利用所设计的导引律导引导弹攻击目标。     

导弹协同作战飞行时间裕度

 基于导弹协同作战任务规划系统进行合理任务分配的需求,研究了导弹可以修正控制飞行时间的裕度。根据导弹-目标在视线坐标系和角动量坐标系下的运动关系,得出了导弹相对于目标的加速度,并基于此给出了导弹剩余飞行时间的估算方法;当前时刻导弹剩余飞行时间的估算值与已经飞行的时间以及任务规划系统指定的期望到达时间构成时间反馈作用,用于修正控制导弹到达目标的最终飞行时间。由于真比例导引律在工程实现和解析运算中具有一定的优势,选择在真比例制导加速度的视线方向施加时间反馈控制作用,进而得出了基于真比例导引律的导弹协同作战飞行时间控制导引律;最后重点研究了在该时间控制导引律的作用下,存在导弹的飞行速度限制以及弹目相对运动约束时,导弹飞行过程中任一时刻对应解析形式的可控飞行时间的裕度。仿真结果表明,本文的设计合理可行,对于多弹协同作战的实现具有重要意义。     

基于锥形运动的制导火箭速度控制导引律设计

针对制导火箭落点速度的约束要求,提出了一种采用锥形运动控制导弹飞行速度的导引方法。该方法首先设计了满足速度约束的虚拟目标理想运动轨迹,将导弹减速控制问题转化为对虚拟目标的追踪导引问题,通过建立制导火箭与虚拟目标的相对运动模型,分析了弹目相对位置和相对速度的关系,推导了具有速度控制的导引律一般形式,并采用动态逆控制理论设计了锥形运动控制指令和导引参数。通过数字仿真对比了不同落角约束条件下导弹锥形运动的速度控制效果,结果表明该方法设计的导引律能够满足制导火箭速度约束要求,且制导精度高、控制效果好,为导弹锥形运动速度控制技术提供了参考。     

Recursive time-to-go estimation for homing guidance missiles

This paper addresses the problem of computing accurate time-to-go estimates, which is an important issue in implementing various optimal guidance laws developed for missiles of time-varying velocity. A recursive time-to-go computation method which updates the time-to-go in a noniterative way is presented. The recursive method includes an error compensation feature which explicitly computes the time-to-go error produced by nonzero initial heading errors. The proposed method is simple and straightforward to implement for any missile velocity profiles. Various numerical examples show that the proposed method works effectively for optimal guidance laws as well as proportional navigation and augmented proportional navigation     

An adaptive fast fixed-time guidance law with an impact angle constraint for intercepting maneuvering targets

Sliding mode guidance laws based on a conventional terminal sliding mode guarantees only finite-time convergence, which verifies that the settling time is required to be estimated by selecting appropriate initial launched conditions. However, rapid convergence to a desired impact angle within a uniform bounded finite time is important in most practical guidance applications. A uniformly finite-time/fixed-time convergent guidance law means that the convergence (settling) time is predefined independently on initial conditions, that is, a closed-loop convergence time can be estimated a priori by guidance parameters. In this paper, a novel adaptive fast fixed-time sliding mode guidance law to intercept maneuver targets at a desired impact angle from any initial heading angle, with no problems of singularity and chattering, is designed. The proposed guidance law achieves system stabilization within bounded settling time independent on initial conditions and achieves more rapid convergence than those of fixed-time stable control methods by accelerating the convergence rate when the system is close to the origin. The achieved acceleration-magnitude constraints are rigorously enforced, and the chattering-free property is guaranteed by adaptive switching gains. Extensive numerical simulations are presented to validate the efficiency and superiority of the proposed guidance law for different initial engagement geometries and impact angles.     

一种弹目遭遇点预测方法

为充分利用舰空导弹中制导段所获信息并减小导弹中制导段的弹道曲率,给出一种弹目预测遭遇点的解算方法,并据此设计比例导引制导律。在初始发射坐标系中,假设目标由当前位置以当前速度大小沿当前速度方向匀速运动至遭遇点,导弹由当前位置以当前速度大小按照一定的导引规律匀速运动至遭遇点。在该假设条件下,导弹到达遭遇点的总航路大小一方面...     

Modified rolling guidance law for single moving mass controlled reentry vehicle against maneuvering target with impact angle constraints

This paper deals with the problem of guidance law design for the single moving mass controlled reentry vehicle when impact angle constraints and maneuvering target are taken into consideration. More specifically, a modified rolling guidance law is proposed with the interactive virtual target and the landing point prediction strategy. First, considering the fact that the roll channel can be controlled directly, the relative motion between the single moving mass controlled reentry vehicle and the ...     

A distributed cooperative guidance law for salvo attack of multiple anti-ship missiles

The consensus problem of impact time is addressed for multiple anti-ship missiles. A new distributed cooperative guidance law with the form of biased proportional navigation guidance(BPNG) is presented. The proposed guidance law employs the available measurements of relative impact time error as the feedback information to achieve the consensus of impact time among missiles and, by exploiting the special structure of the biased cooperative control term, it can handle the seeker's field-of-view(FOV) constraint. The proposed scheme ensures convergence to consensus of impact time under either fixed or switching sensing/communication network, and the topological requirements are less restrictive than those in the existing results. Numerical examples are provided to illustrate the effectiveness of the proposed guidance law.     

Two-phase guidance law for impact time control under physical constraints

An impact-time-control guidance law is required for the simultaneous attack of suicide attack unmanned aerial vehicles. Based on the nonlinear model, a two-phase guidance strategy is proposed. The impact time is derived in a simple analytical form of initial states and switching states, and it can be controlled by switching at an appropriate range. Firstly, a two-phase guidance law is designed to make the magnitude of the heading error decrease monotonically from its initial value to zero. And then, the feasible interval of the switching ranges and of the impact times under the acceleration constraint are given analytically in sequence. Furthermore, a general form of two-phase guidance law is proposed, which allows the magnitude of the heading error to increase in the first phase, to improve the applicability of the methodology. Having the same structure as proportional navigation guidance with a time-varying gain, the proposed algorithms are simple and easy to implement. The corresponding feedback form is presented for realistic implementation. When a predefined impact time is taken within its permissible set, the constraints on the acceleration and field-of-view will not be violated during the interception. Finally, simulations validate the effectiveness of the methodology in impact time control and salvo attack.     

Trajectory reshaping based guidance with impact time and angle constraints

This study presents a novel impact time and angle constrained guidance law for homing missiles. The guidance law is first developed with the prior-assumption of a stationary target, which is followed by the practical extension to a maneuvering target scenario. To derive the closed-form guidance law, the trajectory reshaping technique is utilized and it results in defining a specific poly-nomial function with two unknown coefficients. These coefficients are determined to satisfy the impact time and angle constraints as well as the zero miss distance. Furthermore, the proposed guidance law has three additional guidance gains as design parameters which make it possible to adjust the guided trajectory according to the operational conditions and missile’s capability. Numerical simulations are presented to validate the effectiveness of the proposed guidance law. ? 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).     

Biased PNG law for impact with angular constraint

A new homing guidance law is proposed to impact a target with a desired attitude angle. It is a variation of the conventional proportional navigation guidance (PNG) law which includes a supplementary time-varying bias. The proposed guidance law does not require a time-to-go estimation and has a simpler form. Analytic conditions for fulfilling the guidance goal are also provided. Simulation results demonstrate that the proposed guidance law has wider launch envelopes than the previous one and shows a good performance even against a maneuvering target     

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.     

基于解析剖面的时间协同再入制导

针对高超声速滑翔飞行器再入段时间协同制导问题，提出一种基于高度-速度剖面的预测校正协同制导律。首先在高度-速度剖面内设计了参考轨迹，利用两个轨迹参数在线预测剩余飞行航程和时间；通过数值算法校正两个轨迹参数以满足航程和时间约束并求取实际控制量，结合侧向航向角走廊实现了单飞行器的时间约束再入制导。在此基础上分析了飞行器的时间可调范围，针对多飞行器协同再入任务设计了协同飞行时间和协同策略，实现了时间协同再入飞行。该策略考虑到再入过程中的通讯困难，避免了弹间通讯，且充分利用了飞行器纵向动力学，时间可控范围较大，更加适用于实际的再入过程。仿真结果说明了时间约束再入制导律对时间的可控性和协同策略的有效性。     

Optical flow based guidance system design for semi-strapdown image homing guided missiles

This paper focuses mainly on semi-strapdown image homing guided (SSIHG) system design based on optical flow for a six-degree-of-freedom (6-DOF) axial-symmetric skid-to-turn mis-sile. Three optical flow algorithms suitable for large displacements are introduced and compared. The influence of different displacements on computational accuracy of the three algorithms is ana-lyzed statistically. The total optical flow of the SSIHG missile is obtained using the Scale Invariant Feature Transform (SIFT) algorithm, which is the best among the three for large displacements. After removing the rotational optical flow caused by rotation of the gimbal and missile body from the total optical flow, the remaining translational optical flow is smoothed via Kalman filtering. The circular navigation guidance (CNG) law with impact angle constraint is then obtained utilizing the smoothed translational optical flow and position of the target image. Simulations are carried out under both disturbed and undisturbed conditions, and results indicate the proposed guidance strat-egy for SSIHG missiles can result in a precise target hit with a desired impact angle without the need for the time-to-go parameter.