Small body exploration is a pertinent challenge due to low gravity environments and strong sensitivity to perturbations like Solar Radiation Pressure (SRP). Thus, autonomous methods are being developed to enable safe navigation and control around small bodies. These methods often involve using Optical Navigation (OpNav) to determine the spacecraft's location. Ensuring OpNav reliability would allow the spacecraft to maintain an accurate state estimate throughout its mission. This research presents an observability-constrained Lyapunov controller that steers a spacecraft to a desired target orbit while guaranteeing continuous OpNav observability. We design observability path constraints to avoid regions where horizon-based OpNav methods exhibit poor performance, ensuring control input that maintains good observability. This controller is implemented with a framework that simulates small body dynamics, synthetic image generation, edge detection, horizon-based OpNav, and filtering. We evaluate the approach in two representative scenarios, orbit maintenance and approach with circularization, around spherical and ellipsoidal target bodies. In Monte Carlo simulations, the proposed approach improves the rate of attaining target orbits without observability violations by up to 94% compared to an unconstrained Lyapunov baseline, demonstrating improved robustness over conventional methods.

翻译：小天体探测因低重力环境及对太阳辐射压力等扰动的强敏感性而成为一项重要挑战。因此，自主导航与控制方法的开发对于保障小天体附近的安全运行至关重要。这些方法通常依赖光学导航技术来确定航天器的位置。确保光学导航的可靠性可使航天器在整个任务期间保持精确的状态估计。本研究提出了一种可观测性约束的李雅普诺夫控制器，该控制器在将航天器引导至目标轨道的同时，保证光学导航的持续可观测性。我们设计了可观测性路径约束，以规避基于地平线的光学导航方法性能较差的区域，从而确保控制输入能够维持良好的可观测性。该控制器通过一个集成框架实现，该框架模拟小天体动力学、合成图像生成、边缘检测、基于地平线的光学导航以及滤波过程。我们在球形和椭球体目标天体的两种典型场景（轨道维持与接近圆化机动）中对方法进行了评估。蒙特卡洛仿真结果表明，与无约束的李雅普诺夫基准方法相比，所提方法将不违反可观测性条件下达成目标轨道的成功率提升了最高94%，证明了其相较于传统方法具有更强的鲁棒性。