Development of an autonomous multi-rotor copter for collecting atmospheric data near the ground

Vertical profiling of atmospheric data for the first several hundred meters above ground level is a powerful mechanism by which environmental scientists conduct research and development. Accurate measurements of atmospheric variables such as wind, temperature, and relative humidity, are essential to the many applications of this type of environmental research. The current methods of taking measurements by free-flying or tethered balloons can be inconsistent and unreliable. Beyond the scientific implications, balloons are also unpractical for large research projects that demand multiple profiles at high spatial and temporal resolution. Free-flying balloons and the attached sensors are often not recovered after use, and they can be costly to replace. Tethered balloons can be reused, but the cost of helium as well as the time and work required to operate make them undesirable for repetitive observation. The purpose of this project is to develop an unmanned aerial vehicle (UAV) that can collect atmospheric data for the purpose of generating vertical profiles of the first several hundred meters above the ground. This overall goal for the project includes not only the development of the vehicle itself, but also a data collection system and a mechanism for users to interface with the data both during and after data collection. The system is designed to be pre-programmable and autonomous, providing researchers the precision and control required to generate accurate profiles of the lower atmosphere. It will also be reusable, offering a clear advantage over the traditional balloons, and customizable to fit varying research needs. The system in its current form is a hexacopter built on the open source ArduCopter platform. It is outfitted with an extensive sensor package to measure wind speed and direction, temperature, humidity, and pressure. Data are logged directly to an onboard SD card, and additionally transmitted wirelessly to a laptop ground station when the vehicle is in use. When this team took control of the project, much of the hardware was already in place. As such, the team’s efforts this past scholastic year were 1) the development of a robust information system that will allow users to both see the data in real-time in a useful format and easily manage and process the data after they are measured, and 2) further stabilization of the copter’s flight while hovering at a fixed altitude. In its final form, the copter and its counterpart information system will provide environmental scientists with a powerful tool that will both simplify and augment the process of low-altitude atmospheric research.