Impact time control guidance law with large impact angle constraint

In this work, a new guidance law with a meaningful performance index is designed to satisfy terminal impact angle and impact time constraints based on optimal error dynamics, which can be used for salvo attacks or cooperative missions of multi-missile. The analytical solution of the proposed guidance law is a combination of trajectory shaping guidance law and an additional impact time error feedback term that is proportional to the difference between the desired and the true impact times. Trajectory shaping guidance law aims to achieve the desired terminal impact angle and zero miss distance, whereas the extra term aims to meet the desired impact time. The minimum and maximum feasible impact times that consider the seeker's field-of-view limit, terminal impact angle constraint, and missile's maneuvering acceleration limit are calculated to provide the feasible boundary range of the desired impact time. Numerical simulations of several engagement situations demonstrate the effectiveness of the proposed guidance law in the accuracy of terminal impact angle and impact time.

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Trajectory shaping guidance law design using constraint-combining multiplier

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410020986371 ◽

2021 ◽

pp. 095441002098637

Author(s):

Min-Guk Seo ◽

Chang-Hun Lee ◽

Tae-Hun Kim

Keyword(s):

Design Method ◽

Impact Angle ◽

State Variables ◽

Flight Trajectory ◽

Potential Significance ◽

Guidance Law ◽

Terminal Constraints ◽

The Impact ◽

Guidance Laws ◽

Impact Angle Constraint

A new design method for trajectory shaping guidance laws with the impact angle constraint is proposed in this study. The basic idea is that the multiplier introduced to combine the equations for the terminal constraints is used to shape a flight trajectory as desired. To this end, the general form of impact angle control guidance (IACG) is first derived as a function of an arbitrary constraint-combining multiplier using the optimal control. We reveal that the constraint-combining multiplier satisfying the kinematics can be expressed as a function of state variables. From this result, the constraint-combining multiplier to achieve a desired trajectory can be obtained. Accordingly, when the desired trajectory is designed to satisfy the terminal constraints, the proposed method directly can provide a closed form of IACG laws that can achieve the desired trajectory. The potential significance of the proposed result is that various trajectory shaping IACG laws that can cope with various guidance goals can be readily determined compared to existing approaches. In this study, several examples are shown to validate the proposed method. The results also indicate that previous IACG laws belong to the subset of the proposed result. Finally, the characteristics of the proposed guidance laws are analyzed through numerical simulations.

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Adjustable impact-time-control guidance law against non-maneuvering target under limited field of view

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/09544100211012996 ◽

2021 ◽

pp. 095441002110129

Author(s):

Jun-Yong Lee ◽

Hyeong-Guen Kim ◽

H Jin Kim

Keyword(s):

Field Of View ◽

Control Technique ◽

Moving Target ◽

Time Error ◽

Stationary Target ◽

Impact Time ◽

Maneuvering Target ◽

Time Control ◽

Guidance Law ◽

Intercept Point

This article proposes an impact-time-control guidance law that can keep a non-maneuvering moving target in the seeker’s field of view (FOV). For a moving target, the missile calculates a predicted intercept point (PIP), designates the PIP as a new virtual stationary target, and flies to the PIP at the desired impact time. The main contribution of the article is that the guidance law is designed to always lock onto the moving target by adjusting the guidance gain. The guidance law for the purpose is based on the backstepping control technique and designed to regulate the defined impact time error. In this procedure, the desired look angle, which is a virtual control, is designed not to violate the FOV limit, and the actual look angle of the missile is kept within the FOV by tracking the desired look angle. To validate the performance of the guidance law, numerical simulation is conducted with different impact times. The result shows that the proposed guidance law intercepts the moving target at the desired impact time maintaining the target lock-on condition.

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