The electrical inspection of unmanned aerial vehicles （UAVs） during their autonomous landing at distributed airports is difficult， particularly when the landing cannot be performed accurately， safely， and reliably owing to unsatisfactory light conditions. In this study， a touch-down navigation system for inspecting UAVs was developed. A set of systematic strategies for landing UAVs at distributed airports was proposed， as well as a novel criterion for selecting the landing strategy. First， a touch-down navigation system was established， which included an inspecting UAV， as well as ultrawide band （UWB） positioning modules on the ground and at distributed airports. Second， based on an open-source flight control system， an exclusive landing flight controller was designed and embedded into the UAV， and a novel speed controller and algorithm for landing were designed. Third， an evaluating criterion for the landing strategy was proposed， and systematic landing strategies were proposed to accommodate challenging circumstances. Experimental results indicate the following： The landing error is within 0.3 m， and the reliability is 100%； the touch-down navigation system can guide the UAV to land safely and accurately when one or two UWB modules on the ground are disabled； each landing strategy presents its own advantages and can accommodate different landing circumstances. The touch-down navigation system can satisfy the requirements of UAVs for autonomous landing， and the proposed landing strategies significantly improve the landing reliability， thus providing a foundation for the construction of autonomous UAV systems intended for power grid inspection.