Design, Manufacture, and Testing of Volume Scanning Mechanisms for a Lidar and Radar Sounder
Document ID: 101
Master's Thesis
The Pennsylvania State University
The Graduate School
Department of Aerospace Engineering
Abstract
Understanding the physical mechanisms involved in complicated atmospheric processes, such as cloud formation, requires simultaneous measurements of many atmospheric parameters. However, because individual systems such as lidars and radars measure only a few quantities as functions of space and time, complete data sets are rarely obtained and the majority of data acquired by individual instruments is under-utilized. To improve this situation, a group of researchers at Penn State University is building an integrated observing system featuring simultaneous measurements by several instruments. This integrated system is being developed to simultaneously measure condensed water, aerosols, temperature, and water vapor in a volume of the troposphere. The measurements will be made with lidar and radar systems that are mounted on volume scanning mechanisms.
This thesis addresses the development, design, manufacture, and testing of the volume scanning mechanisms for the lidar and radar systems. Design requirements, based on the scientific needs for the project, include a 10 degree per second scanning rate with a 0.1 degree accuracy and reproducibility. Eight initial concepts were developed and reduced to three concepts by preliminary assessments of performance and practicality. The three retained concepts were analyzed for motor sizing, feasibility, and cost to determine the final focus design.
Two identical structures, one for the each of the lidar and radar systems, using micro-stepping motors with 20:1 gear reduction were manufactured to move the atmospheric measuring systems. The motors are controlled with a 4-axis, closed-loop controller that is run from a PC to create motion in the azimuth and elevation coordinates. A test plan was developed to determine the capabilities and limitations of the system.
| Citation: | T. E. Manning II, "Design, Manufacture, and Testing of Volume Scanning Mechanisms for a Lidar and Radar Sounder", The Pennsylvania State University, Master's Thesis, August 1993, 146 pages |