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This article proposes barrier Lyapunov function-based guidance strategies to achieve target interception, by a seeker-equipped interceptor having a limited field-of-view (FOV), at a prespecified impact time. A novel approach to respect the FOV constraint, using the conditions on time-to-go of the engagement, is first proposed. Guidance commands are then derived to steer the course of the interceptor in a way so as to adhere to the necessary conditions. Guidance strategy is first derived for 3-D engagements, and then, the same for planar scenarios is presented as a special case. The set of achievable impact times for given initial conditions, while satisfying FOV constraints, is first obtained, and then, a way to expand the achievable range of impact time is suggested using a two-stage approach. The behavior of lead angle is analyzed, and it is shown that guidance commands remain nonsingular and converge to zero near interception. Simulations are shown to validate the efficacy of proposed methods for various initial engagement geometries. [ABSTRACT FROM AUTHOR]

In this article, a nonlinear three-dimensional guidance strategy for multiple identical constant speed interceptors is proposed to capture a stationary target simultaneously. To design this proposed guidance strategy, a proportional navigation based time-to-go estimate, without any small angle assumption, is used. Based on the maximum value of time-to-go estimates of all interceptors, the range error for each interceptors is computed. Sufficiency conditions for simultaneous capture are satisfied by ensuring the range errors and their rates converge to zero for all interceptors. The proposed guidance strategy employs Lyapunov and sliding-mode control-based techniques to achieve these sufficiency conditions. Simulation studies demonstrate that this proposed strategy performs satisfactorily for various geometric engagements and in the presence of a first-order autopilot. [ABSTRACT FROM AUTHOR]

This article proposes a leader–follower cooperative salvo guidance strategy to intercept nonmaneuvering targets by exploiting the advantages of supertwisting sliding mode control. An improved estimate of time-to-go, that does not assume interceptor's small heading angle, is used in the guidance design. This allows the guidance strategy to remain effective even for large initial heading of the interceptor. Under the action of supertwisting control, the error in impact time settles precisely to zero in finite time. The proposed guidance strategy provides robustness against uncertainties and a smooth control signal, along with finite-time convergence of error. The guidance performance has been shown for one-to-one engagement, and in a cooperative framework, to achieve a salvo in a predetermined time. Numerical simulations are presented for various engagement scenarios to aid the analysis, and illustrate the efficacy of the proposed guidance scheme, even under noisy environment. [ABSTRACT FROM AUTHOR]

This paper proposes integrated guidance and control design to intercept a target, which may execute various motions, at a pre-specified time of interception. The problem is addressed considering nonlinear engagement kinematics and the interceptor is steered using the combined effects of canard as well as tail configurations (dual-controlled interceptors). Different formulations of time-to-go, without the restrictive assumption of interceptor's small heading angle, have been used in deriving the guidance commands, allowing the proposed strategy to remain effective over a wide range of impact time values. A weighted effort allocation scheme, in canard and tail deflections, has been proposed to generate the required lateral acceleration. The overall design uses sliding mode control owing to its simplicity of design, while a nonlinear finite-time disturbance observer is used to estimate the target's maneuver. Finally, simulations are presented for various target motions, and time-constrained interception with an impaired actuator is also shown, vindicating the efficacy of the proposed technique. [ABSTRACT FROM AUTHOR]