The Active Range of the Optical Systems Test Facility was established in 2003 to allow for rapid development and demonstration of active electro-optic technology in a system context, investigate critical phenomenology issues in a repeatable environment, and enhance expertise in electro-optic technology. The test facility consists of four major parts: a control room, a 50-m range with installed ladar systems, a far-field emulator comprising of a 1-m primary mirror and zoom optics, and a dynamic target manipulator for full-scale (1-m) targets. This paper will focus on the capabilities of the Optical Systems Test Facility and present some examples of laser radar experiments and data taken in the range.
The Optical Systems Test Facility was established at MIT Lincoln Laboratory to support a broad scope of program areas, encompassing tactical ground-based sensors through strategic space-based sensors. The Optical Systems Test Facility comprises several separate ranges developed as a coordinated set of test sites at MIT Lincoln Laboratory. There are currently four separate ranges in the facility, an active range (Laser Radar Test Facility), a passive range (Seeker Experimental System), an aerosol range (Standoff Aerosol Active Signature Testbed) and an optical material measurements range. The active range has optical and target facilities for evaluating elements of laser radar sensors as well as complete ladar systems. It has facilities for simulating long range wavefronts and for dynamic target motions. The passive range concentrates on evaluating passive infrared sensors, with capabilities for static and dynamic scene generation in both cryogenic and room temperature environments. The aerosol range is currently configured for the measurement of both particulate and bio-agent aerosol dispersion characteristics. The optical materials measurements range started with measurement capabilities for laser radar target materials and is currently being expanded to measure both emissivity and reflectance of materials from the visible through the infrared.
The Seeker Experimental System (SES) is the passive range within MIT Lincoln Laboratory's Optical System Test
Facility (OSTF). The SES laboratory focuses on the characterization of passive infrared sensors. Capable of projecting
static and dynamic scenes in both cryogenic and room temperature environments, SES supports sensors that range from
tactical ground based systems through strategic space-based architectures. Optical infrared sensors are a major
component of military systems, having been used to acquire, track, and discriminate between potential targets and
improve our understanding of the physics and phenomenology of objects. This paper delineates the capabilities of the
SES laboratory and describes how they are used to characterize infrared sensors and develop new algorithms and
hardware in the support of future sensor technology. The SES Cryogenic Scene Projection System vacuum chamber has
recently been upgraded to allow dynamic projection of radiometrically accurate two-color infrared imagery. Additional
capabilities include the ability to combine imagery from multiple sources, NIST traceable radiometric calibration, and
dynamic scene projection in an ambient environment using a combination of high speed mirrors, point source
blackbodies, and resistive array based dynamic infrared scene projectors.
The Standoff Aerosol Active Signature Testbed (SAAST) is the aerosol range within the MIT Lincoln Laboratory's Optical System Test Facility (OSTF). Ladar and Lidar are promising tools for precise target acquisition, identification, and ranging. Solid rocket effluent has a strong Lidar signature. Currently, calculations of the Lidar signature from effluent are in disagreement from measurements. This discrepancy can be addressed through relatively inexpensive laboratory measurements. The SAAST is specifically designed for measuring the polarization-dependent optical scattering cross sections of laboratory-generated particulate samples at multiple wavelengths and angles. Measurements made at oblique angles are highly sensitive to particle morphology, including complex index of refraction and sample shape distribution. With existing hardware it is possible to re-aerosolize previously collected effluent samples and, with online and offline diagnostics, ensure that these samples closely represent those found in situ. Through comparison of calculations and measurements at multiple angles it is possible to create a realistic model of solid rocket effluent that can be used to extrapolate to a variety of conditions. The SAAST has recently undergone a dramatic upgrade, improving sensitivity, flexibility, sample generation, sample verification, and level of automation. Several measurements have been made of terrestrial dust and other samples.