Guidance navigation and control for approaching upper-stage rocket body using illumination-robust event camera

Active space debris removal is required for upper-stage rocket bodies, and removal satellites need to recognize the circular shape of the upper-stage rocket body as a visual marker and approach it by utilizing on-board visual sensors. However, the lighting conditions make it difficult to observe the target stably. Moreover, limited power resources of removal satellites is also a limitation. This study proposes a method to detect the circular shape of upper-stage rocket bodies using an event camera as a visual sensor, which is robust to lighting conditions and has low power consumption. The output of an event camera becomes sparse when the relative velocity to the target is low, making ellipse tracking challenging. To address this, this study proposes a method to accumulate events over a defined period and track ellipses based on the number of accumulated events. Additionally, a passivity-based control method utilizing ellipses tracked by the navigation system is proposed for guidance and control. Simulations were conducted to verify the robustness of the proposed method under varying sunlight conditions.