ARL Electro-Optics Laboratory Lidar Applications
Document ID: 356
1 The Pennsylvania State University, Applied Research Laboratory, Electro-Optics Department
Presented: The Pennsylvania State University
Pennsylvania, 1987
Abstract
Over the past five years ARL has established a capability for optical and spectroscopic research, and the development, design, prototyping, and testing of electro-optical instruments and systems. The Laboratory is in a position to exploit the rapidly developing technology of lasers and electro-optical devices for basic research and advanced system development. Familiarity with diverse sensors and the electronics for mating them with digital signal processing systems is leading to improvements in techniques for the acquisition of atmospheric and oceanographic data.
Laser experiments in light propagation through air and water are underway. The present emphasis is on lidar systems that transmit pulsed laser light and measure the intensity of backscattered light in a manner analogous to radar. Lidar, operating in the infrared, visible and ultraviolet spectral regions, is a unique tool for monitoring the atmosphere. It can provide data on meteorological phenomena, and can measure atmospheric properties of interest for the development of future optical communication and tracking systems. There will be similar opportunities in the next decade for the development of underwater electro-optical systems.
The ARL Electro-Optics Laboratory is a center for a wide range of research and development activities, applying state-of-the-art optical techniques and devices to scientific investigations and advances in technology. Current efforts are in the application of lidar systems for remote sensing of atmospheric properties, and studies of underwater propagation of light in the bluegreen spectral region. Experiments with ARL's Lidar Atmospheric Measurements Profiler (IAMP) providedata on meteorological phenomena, atmospheric chemistry and dynamics, and microwave refractivity. Investigations of underwater propagation will produce data to support the development of underwater lidar, imaging, and communication systems. The laboratory has several special instruments and facilities backed up by a wide variety of test equipment and calibration systems.
A major effort is on the development of a Lidar Atmospheric Profile Sensor (LAPS), the prototype of an operational meteorological instrument. The LAPS will become a key component of the Navy's Shipboard Meteorological and Oceanographic Observing System (SMOOS) to provide data inputs to Tactical Environmental Support System 3 (TESS3). The LAPS program is sponsored by the Environmental Program Office of SPAWAR (PMWl 65). Navy plans call for LAPS sea tests in 1995, a step in the transition from basic research ( 6.1) to hardware demonstration ( 6. 4) within a five-year time frame.
Another system scheduled for completion in 1993 is the Water Aerosol/Vapor EnvironmentLidar And Radar Sounder (WAVE-LARS) to investigate aerosols and clouds, sponsored by the Department of Energy. The goal is a better understanding of environmental effects of the national fuel policy. The WAVE-LARS uses a volume-scanning lidar to investigate microphysical processes such as cloud formation. Data on aerosol scattering at multiple wavelengths will provide critical information on radiative transport of energy in the atmosphere. Programmed simultaneous scans by lidar and 94-GHz radar will provide repeated mapping of a selected volume of the atmosphere. The lidar and radar returns are processed in real time to produce a common database. The instruments are housed in shipping containers. and can be set up to operate as a remote field laboratory.
A Giant Atmospheric Lidar (GAL) is being assembled from residual property from major programs of the Navy and the Penn State Astronomy Department. Its transmitter is a large injection-seeded excimer laser with an output of more than 250 watts. The receiver uses seven mirrors of one-meter diameter in a close-packed hexagonal array. With a signal intensity, three orders of magnitude higher than that of the best current lidar sounders, the GAL, will make measurements to the heights of low-orbit satellites. It will measure minor atmospheric species in regions previously inaccessible to remote sensing. The Electro-Optics Laboratory is also equipped to investigate underwater light propagation with several Lasers at different wavelengths. Measurements of depolarization, attenuation, time-domain pulse spreading, and spatial beam spreading produce information on the basic physical properties of the waters of different oceanic regions.
| Citation: | "ARL Electro-Optics Laboratory Lidar Applications", Philbrick, C. R., The Pennsylvania State University, 1987, pp. 36 - 40 |