Bounded-Input True Proportional Navigation for Impact-Time Control

2026-05-13

AI Summary

This study addresses precise impact-time control for constant-velocity non-maneuvering targets within the true proportional navigation guidance (TPNG) framework while strictly enforcing bounded control inputs. By incorporating an accurate closed-form expression for time-to-go, the interceptor’s acceleration is modeled as a bounded dynamic variable, and a sliding mode control–based guidance law is developed that explicitly embeds input saturation constraints—eliminating the need for small-angle assumptions or linearization approximations. To the best of the authors’ knowledge, this is the first approach to directly handle input saturation within the TPNG paradigm, making it suitable for a wide range of engagement geometries. Numerical simulations demonstrate that the proposed guidance law consistently satisfies acceleration limits and achieves the desired impact time with high precision across diverse interception scenarios.

Abstract

This paper proposes a nonlinear guidance strategy capable of intercepting a constant-velocity, non-maneuvering target while strictly satisfying the prescribed bounds on the control input (commanded acceleration). Unlike conventional strategies that estimate time-to-go using linearization or small-angle approximations, the proposed strategy employs true proportional-navigation guidance (TPNG) as a baseline, which utilizes an exact time-to-go formulation and is applicable over a wide range of target motions. In contrast to most existing strategies, which do not incorporate control input bounds into the guidance design, the proposed approach explicitly accounts for these limits by modeling the interceptor acceleration as a dynamic variable. Based on the sliding mode control technique, an effective guidance law that achieves time-constrained interception while accounting for bounded input is then derived. The performance of the proposed strategy is evaluated for various engagement scenarios.

Problem

• impact-time control
• bounded control input
• true proportional navigation
• interception
• time-to-go

Innovation

• True Proportional Navigation
• bounded control input
• impact-time control
• sliding mode control
• time-to-go estimation