Three-Dimensional Nonlinear Guidance with Impact Time and Field-of-view Constraints

TL;DR

This paper develops a novel three-dimensional guidance law for intercepting targets within a specified time and field-of-view constraints, improving performance and avoiding reliance on time-to-go estimates.

Contribution

It introduces a new guidance strategy using velocity lead angles and backstepping that extends 2D guidance to 3D without requiring time-to-go estimation.

Findings

The proposed guidance law achieves successful interception within impact time bounds.

It outperforms existing guidance strategies in simulations.

The method effectively manages field-of-view constraints without high-frequency switching.

Abstract

This paper addresses the time-constrained interception of targets at a predetermined time with bounded field-of-view capability of the seeker-equipped interceptors. We propose guidance laws using the effective lead angle and velocity lead angles of the interceptor to achieve a successful interception of the target. The former scheme extends the existing two-dimensional guidance strategy to a three-dimensional setting. We have shown that such an extension may result in high-frequency switching in the input demand, which may degrade the interceptor's performance. To overcome the potential limitations of such a guidance strategy, we propose an elegant solution using the velocity lead angles and the range error with a backstepping technique. Using the velocity lead angles as virtual inputs, the effective lead angle profile is subsequently regulated to satisfy the seeker's field-of-view bound. Unlike the existing strategies, the proposed guidance strategy does not rely on the time-to-go estimate, which is an appealing feature of the design, as the time-to-go estimate may not always be available with high precision. We provide a theoretical analysis of the error variable and subsequently analytically derive the bounds on achievable impact times. Numerical simulations are performed to support the theoretical findings. The performance of the proposed guidance strategy is compared with that of an existing one, and it has been shown to yield better performance. Finally, a study on different choices of virtual inputs is also provided.