Development of an Unmanned Aerial System for Maritime Environmental Observation

Abstract

We developed an octocopter-based unmanned aerial system (UAS) to monitor remote environments. The system contains various environmental monitoring sensors that measure wind speed and direction, temperature, relative humidity, atmospheric pressure, fine dust, and multispectral and RGB data. We studied the UAS—consisting of an unmanned aerial vehicle (UAV), a ground control station, and a server—with respect to its electrical, mechanical, and software (SW) configurations. Specifically, we developed both hardware (HW) and SW to control the yaw and gimbal pitch directions of a UAV conveying multispectral and RGB cameras. To prevent the obtained solar reflectance from affecting the multispectral and RGB data and to improve the quality of the obtained data, we maneuvered the yaw so that it would always deviate 135° from the solar azimuth angle, with the sun at its rear. Managing the yaw direction involves controlling the UAV based on the micro air vehicle link (MAVLink) message-based robot operating system (ROS), MAVROS. To safely test the UAS performance before the maiden flight in an ocean area, we first evaluated PX4 and ROS-based SW through indoor software-in-the-loop simulation (SILS) by using the Gazebo tool. After the SILS experiment, we used an F450 UAV and an actual maritime UAV to perform pre-flight and flight experiments sequentially. This paper explains the system operation scenario, UAS component, and simulation and experimental results. According to the results, the average yaw angle error during the mission, |θy,des -θy|, is approximately 8°, and the average pitch angle of the gimbal during the mission, |50° - |θc||, is less than 5°.