We propose a method for autonomous precision drone landing with fiducial
markers and a gimbal-mounted, multi-payload camera with wide-angle, zoom, and
IR sensors. The method has minimal data requirements; it depends primarily on
the direction from the drone to the landing pad, enabling it to switch
dynamically between the camera's different sensors and zoom factors, and
minimizing auxiliary sensor requirements. It eliminates the need for data such
as altitude above ground level, straight-line distance to the landing pad,
fiducial marker size, and 6 DoF marker pose (of which the orientation is
problematic). We leverage the zoom and wide-angle cameras, as well as visual
April Tag fiducial markers to conduct successful precision landings from much
longer distances than in previous work (168m horizontal distance, 102m
altitude). We use two types of April Tags in the IR spectrum - active and
passive - for precision landing both at daytime and nighttime, instead of
simple IR beacons used in most previous work. The active IR landing pad is
heated; the novel, passive one is unpowered, at ambient temperature, and
depends on its high reflectivity and an IR differential between the ground and
the sky. Finally, we propose a high-level control policy to manage initial
search for the landing pad and subsequent searches if it is lost - not
addressed in previous work. The method demonstrates successful landings with
the landing skids at least touching the landing pad, achieving an average error
of 0.19m. It also demonstrates successful recovery and landing when the landing
pad is temporarily obscured.

无人机自主精确降落方法：利用标志物和云台式多传感器相机（包括广角、变焦和红外传感器）进行精确降落，通过使用不同传感器和变焦倍数，消除了大部分辅助传感器要求，最大程度利用了航向信息，以及利用红外标志物在昼夜间进行精确降落，提出了初始搜索和丢失后的搜索的高级控制策略。