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.ngetikin.com/limited-save-Apple-iPhone-14-Pro-Clear-Case-with-MagSafe-save-big/