Autonomous Circling Tracking Control of Loitering Munitions Against Moving Targets

Loitering munitions are capable of conducting reconnaissance and strike missions against ground personnel and armored vehicles in low-altitude airspace, and have been widely used in combat. However, their deficiency in tracking moving targets continuously has also exposed. Field tests conducted in this study revealed that unexpected target maneuvers, limited tracking control, and field-of-view (FoV) constraints of the seeker can lead to tracking failures, especially when the loitering munition flies directly over the target early in engagement.To address this issue, this paper examines a typical operational scenario where a loitering munition (30 m/s) tracks a mobile self-propelled artillery target (10 m/s). It analyzes how traditional L1 guidance can cause the munition to overshoot the target point during circling maneuvers, resulting in seeker lock failure. This phenomenon is defined as the "overshoot problem" in this article. Based on the performance characteristics of both the loitering munition and its seeker, an autonomous tracking strategy using a fixed-radius circular path centered on the target is proposed. And a modified L1 guidance method is developed to improve tracking performance. The proposed method is implemented based on the open-source PX4 flight control system and is verified through the hardware-in-the-loop simulation and flight tests. Simulation and test results show that the proposed tracking method solves the overshoot problem effectively. It enables continuous tracking of ground targets with a speed up to 15 m/s. Analysis result shows an average tracking time ratio of 82.5% and a relative error of 5.26%, confirming improved tracking performance under constrained FoV conditions.