Bounded-Input True Proportional Navigation for Impact-Time Control

TL;DR

This paper introduces a nonlinear guidance law that ensures interception of a non-maneuvering target within specified control input bounds using true proportional-navigation and sliding mode control.

Contribution

It develops a novel guidance strategy that explicitly incorporates control input limits into the true proportional-navigation framework using sliding mode control.

Findings

Successfully intercepts targets with bounded acceleration commands.

Employs true time-to-go formulation for wide-range target motions.

Achieves time-constrained interception with control input constraints.

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.