Low-Altitude Laser Altimeter to Assist UAV Autolanding

Abstract

This project presents a low-altitude laser altimeter system to assist UAV autolanding. This system generates aircraft altitude and attitude estimates; it consists of laser illuminators, a digital imaging unit (image sensor, lens, and optical filter), and a processor. The purpose of this project is to provide real-time altitude above terrain, roll, and pitch to an existing onboard autopilot system with sufficient accuracy to facilitate the automated landing of the UAV on uncharted landing strips. The laser altimeter system presented by this project employs an optical triangulation concept to estimate the altitude above terrain, roll, and pitch of the aircraft. To implement this system, the Leopardboard 365 is used for the processor; the digital imaging unit is comprised of the Aptina MT9P031 CMOS image sensor, the SY110M ultra-wide angle lens, and the Edmund Optics 780-nm bandpass optical filter; and, four US Lasers 780-nm laser diode modules act as the laser illuminators. Finally, a test fixture was built to assess the speed and accuracy of the system.