Autonomous landing is a challenging but important task for Unmanned Aerial Vehicles (UAV) to achieve high level of autonomy. The fundamental requirement for landing is the knowledge of the height above the ground. and a properly designed controller to govern the process. This paper presents our research results in the study of landing an autonomous helicopter. https://www.alarecre.com/Virescent-Harmony-Galaxy-A14-5G-Clear-Case-p106336/