This PDF file contains the front matter associated with SPIE Proceedings Volume 1725, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

'If I have seen further it is by standing on the shoulders of giants.' Sir Isaac Newton.It has been rightly pointed out that such has been the expansion of science in the twentiethcentury that well over 50% of scientists known to history are still alive today. Indeed, in awondrously mixed metaphor, one present-day researcher has stated that "In the sciences, we arenow uniquely privileged to sit side by side with the giants on whose shoulders we stand." Andnowhere is that more true than in the field of research covered by this Conference. Those of uswhose far-infrared experience reaches back to the 1950s will remember that virtually the onlysource we had was a mercury arc lamp and the only detector was a Golay. There were no booksand just a handful of relevant papers. Even by 1970 the authors of the introductory paper at theBrooklyn Symposium on Submillimeter Waves were writing "It is appropriate to view thesubmillimeter wave region as a transition region lying between the millimeter wave and infraredportions of the electromagnetic spectrum and possessing as yet no hallmark of its own". Thatwas perhaps a pessimistic summary, as there were nearly sixty papers at that meeting. Now thatwe have an annual conference - this one with over three hundred papers - I think we can say thatwhat used to be called the 'unexplored region' is being fully explored.

This paper describes Long Jump 4, a Government-contractor cooperative test of IR and EO sensor technology sponsored by the Naval Weapons Center, China Lake, California. The 10 days of testing took place in August 1990 at Barcroft Laboratory, a research facility run by the University of California, Los Angeles, and located above the 12,000-foot altitude in California's White Mountains. Long Jump 4 involved 14 different types of aircraft flying missions against a variety of infrared (IR) and electro-optical (E0) sensor systems. The data generated during Long Jump 4 is being used by technology users, developers, and manufacturers.

An IRAMMP field measurement exercise was conducted during July 1990 in the Florida Keys. The purpose of the exercise was to investigate horizon radiance phenomenology and associated clutter structure. In the exercise both the IRAMMP sensor and a PtSi imager were used. The sensors were located 31 m above the surface of the water in a ocean side apartment building. The IRAMMP sensor is a dual band 120 element radiometric scanner with an IFOV of 250 microradians. The PtSi sensor was a commercial staring instrument with a 85 microradian IFOV. High quality digital data were obtained on a number of days and nights over a three week time span. In most of the data sequences a bright IR point source on a small boat was observed as it transited over the horizon. The precise range to the point source was recorded at all times. An excellent set of meteorological "ground truth" data was collected in conjunction with a parallel NRL/NOSC field exercise called KEY90. This paper is a partial report on results obtained from the analysis of data from the Florida field measurements. Emphasis in this paper will be on three aspects of the low horizon phenomenology. These are: 1) the form of the radiance profile singularity in the vicinity of the horizon line, 2) the appearance of a point source as it traverses the horizon, and 3) the solar glitter pattern seen on the water under a favorable illumination geometry.

A model-based automatic target recognizer (ATR) is described. This system identifies, determines the aspect, and determines the range of aircraft based on their shape. The system is a knowledge- based system which utilizes the U.S. Army's Visual Aircraft Recognition Manual. It recognizes aircraft based on the FLIR or TV image of the target. The specific techniques that are used by the target recognizer to find the range, aspect angles, and identification of targets are described. Tests results obtained at the Naval Weapons Center sponsored Long Jump IV test are also described. Average identification, range, and aspect error are given.

A unique set of spectrally resolved line-of- sight radiance measurement from a large (100k lbs thrust) solid propellant rocket motor exhaust plume ob- served at low altitude static conditions is presented. Measured spectra from a line-of-sight through the plume about a nozzle diameter downstream from the exit plane in the spectral region 1-5.5 gm are com- pared with predictions from the signature code combi- nation RAMP/SPF-II/SIRRM-II. There is excellent agreement between the measurements and predictions over all but the spectral interval 1-2.25 gm. Particle thermal emission is the dominant source in this spectral region. It is suggested that the current database of A1203 particle index of refraction yields too small ab- sorption cross sections for this particular motor. This set of measured spectra is recommended to the plume signature community as a valuable basis for signature code validation.

Predictions of near exit plane spectral radi- ance are made with CHARM 1.3 and compared with a unique set of vacuum plume measurements from solid propellant rockets. Two propellants are used, a nomi- nal 15 percent and a low 2 percent Al-loading. A small research motor with three nozzles was used. These noz- zles included a conical and a contoured expansion with area ratios of 40 and a conical expansion with an area ratio of 10. Spectra between about 1.9 and 5.2 gm along with some gas dynamic measurements were ob- tained. Predictions agree with measurements near the exit plane for the low Al-propellant which is very nearly like a purely gaseous plume. Predictions for the nominal Al-propellant are greater than the measure- ments near the exit plane. It is suggested that CHARM overpredicts the particle temperatures in the nozzle. The utility of simple research-like tests to validate plume signature codes is emphasized.

Aerodyne has recently developed an "IRST Engagement Model" under contract for Lockheed Aeronautical Systems Company [LASC]. The model's purpose is to simulate the performance of an IRST system in long-range air-to-air detection and tracking engagements. The hallmark of the model is its end-to-end first-principles modeling of all major elements which determine specific performance. The target aircraft IR signature, the atmospheric cloud and sky background, and associated atmospheric effects are modeled at high fidelity, thereby producing an input image matched to the specific IRST under study. A detailed deterministic model of the IRST accounts for optical and sensor effects, signal processing, and track association typical of first-generation IRSTs. These model elements are coupled together along with a dynamic target and observer [IRST] trajectories model so that an analyst can specify air-to-air engagements at various velocities, ranges, and viewing angles. The analyst can study the effects of varying IRST algorithms, sensor characteristics, optical bandpass, cloud background levels, atmospheric effects, and target performance characteristics as well as varying the target aircraft itself. This computer model was designed for portability and growth.

The optical performance of near-horizon viewing infrared airborne sensors is affected by atmospheric variations along the line of sight, which are associated with (a) ambient atmospheric vertical structure and turbulence, and (b) the aircraft boundary layer. We have modeled systematic (non-fluctuating) errors and random variations in line-of-sight (LOS) angle and target intensity for several MWIR and LWIR wavelengths as a function of LOS elevation angle from a high altitude aircraft-borne sensor. A range of atmospheric temperature, density, and structure models was used to investigate the sensitivity of target scintillation, jitter angle, and image spread effects to altitude.

The latest version of the Strategic High-Altitude Radiance Code, is now ready for distribution. It calculates atmospheric radiation and transmission for arbitrary paths between 50 and 300 km altitude. The new version contains significant upgrades which include a fully integrated auroral model with time-dependent chemistry, extension down to 50 km altitude and the important isotopes of CO2.

Clutter scenes are nonstationary in space and in time. In order to model clutter environments for extended spatial regions over lengthy time intervals, it is necessary to address the requirements for extended dynamic nonstationary scene generation. This capability is important for testing and evaluating clutter mitigation algorithms that employ spatiotemporal filtering techniques. Traditional Fourier-based and Autoregressive/Moving Average-based (ARMA-based) methods are compared and contrasted for their utility in meeting the objectives of dynamic scene generation. It is shown that Fourier-based approaches can be computationally intensive and that ARMA-based approaches require long warmup periods for structures having long temporal correlations. An alternative approach is presented referred to as the MEMERS (Multiple Extended Moving Evolving Radiance Screens) technique that is computation efficient and satisfies the specified nonstationary spatiotemporal clutter statistics. The MEMERS technique uses multiple radiance screen projection planes to achieve angle decorrelation of clutter scenes. It is shown that by applying motion vectors and imposing time evolution to each projection plane, dynamic clutter scenes having the proper nonstationary spatiotemporal statistics with proper space, time, and angle correlations is achieved.

The present version of the PRUV code (Plume Radiation of Ultra-Violet) utilizes flowfield input from the JANNAF SPF2 code and computes plume ultra-violet spectral signatures resulting from the emissions of CO-0 chemiluminescence, aluminum oxide, zirconium oxide or carbon particulates, and the individual lines of four molecular band systems. Collision and Doppler effects are computed for each molecular line for use in absorption calculations. Spectral signatures were computed for two missiles, herein named Missile A and Missile B. The Missile A plume contains aluminum oxide particulates while those of Missile B are composed of zirconium oxide. Temperature dependent imaginary refractive index (n ) values of zirconium oxide were estimated through use of the phenomenological Urbach Tail Model. Agreement with measured results for both missiles was generally within a factor of two. Such agreement is considered good for this stage of development of the code. A brief description of the present stage of development of the PRUV code is given.

The DELTA STAR 17 sensor launched by Delta 183 presents a unique opportunity to examine the physical properties of earth backgrounds at spatial and temporal resolution not previously available in the 2.7µm water and 4.3µm CO2 absorption bands. However, due to partial instrument failure, and to certain design features, we have had to develop a very complicated calibration procedure for the data. We have designed and fabricated a special purpose analog video signal manipulation and storage device to allow us to recover data from the sensor. We have analyzed one background scene containing the earth limb and mid and high level clouds of various types in the 2.7 µm band. We have obtained calibrated intensity values, and energy distribution such as power spectral density. Our preliminary results indicate that clouds show a log normal (definitely non-Gaussian) intensity distribution. We hope to examine spatial decorrelation lengths, intensity gradients and the short term temporal variations in cloud properties, and as we acquire more scenes, the variation of gross cloud morphology. We also intend to examine the 4.3µm data, particularly to determine if small scale structure (contrast variations) are observable at or near the specular point.

The Strategic Defense Initiative (SDI) must simulate the detection, acquisition, discrimination and tracking of anticipated targets and predict the effect of natural and man-made background phenomena on optical sensor systems designed to perform these tasks. NRL is developing such a capability using a computerized methodology to provide modeled data in the form of digital realizations of complex, dynamic scenes. The Strategic Scene Generation Model (SSGM) is designed to integrate state-of-science knowledge, data bases and computerized phenomenological models to simulate strategic engagement scenarios and to support the design, development and test of advanced surveillance systems. Multi-phenomenology scenes are produced from validated codes - thereby serving as a standard against which different SDI concepts and designs can be tested. This paper describes the SSGM architecture, the software modules and data bases which are used to create scene elements, the synthesis of deterministic and/or stochastic structured scene elements into composite scenes and scene sequences, and the software system to manage the various data bases and digital image libraries. We will discuss the existing Prototype Model (SSGMP) and the design architecture of the fully-functional Baseline Model (SSGMB) which is currently being developed. We will also describe the relationship between this project, the phenomenological models, and proposed data centers to improve access to the relevant empirical data.

The Strategic Scene Generation Model (SSGM) generates representations of terrain and cloud background images using government standard codes: Generic Scene Simulation Software (GENESSIS) for terrain and Cloud Simulation (CLDSIM) for clouds. The SSGM generates image representations of the plumes of boosting missiles and midcourse hardbo.dy post-boost vehicles, reentry vehicles, and decoys. Plumes are represented using the Standard Plume Flowfield - Version 2 (SPF2) and the Standard Infrared Radiance Model (SIRRM) for altitudes less than 50 km, and the Composite High Altitude Radiance Model (CHARM) 1.2 for altitudes above 50 km. Midcourse vehicles are represented using the BIDIRC software of the Optical Signatures Code (OSC). The plume and midcourse images are overlayed upon background images to generate composite output scenes. This paper presents the automated methodology by which the SSGM interfaces with the user to invoke the execution of the requisite computer codes, formats code output for input to the scene generation process, interpolates and resamples code output to form images, and overlays individual images into composite scenes. This paper also presents overviews of the GENESSIS and CLDSIM codes, including discussions of the procedures used to treat the various radiation mechanisms. Example outputs from GENESSIS and CLDSIM are presented in addition to plume images as they appear when composited with the background images.

Surveillance systems, especially for mid-course detection missions, must acquire and track targets against a naturally structured earthlimb and aurora background. The background levels are highly variable both in wavelength and radiance. "Standard" one-dimensional line-of-sight models for describing such backgrounds have been developed by organizations such as the Geophysics Laboratory, Naval Research Laboratory and Defense Nuclear Agency. As part of the newly established SDI/NRL Strategic Scene Generator Model effort, we have developed techniques for applying these background models to represent multi- dimensional earthlimb and aurora background scene realizations. We present these model techniques and sample scene results for both earthlimb and auroral phenomenology. Naturally occurring statistical structure for both earthlimb and aurora modelling is described as it effects clutter representation in the scenes. Specific systems-oriented scene realizations are illustrated.

The structured infrared backgrounds created by nuclear detonations in the atmosphere are an important element of the scenes generated by the SSGM code. SSGM utilizes state-of-the science Defense Nuclear Agency (DNA) computer codes to provide nuclear disturbance caused environments. The SSGM Prototype was delivered with a data base for a single nuclear burst (10 Megatons at 120 km) in three spectral bands (SWIR, MWIR and LWIR). The data base was generated with the DNA NORSE code. The Baseline SSGM will have a more robust capability to generate Nuclear Backgrounds with the incorporation of the DNA PEM code into its run- time generation capabilities. PEM (Propagation Engagement Module) calculates propagation environments from a NORSE-generated data base. NORSE-gener- ated data bases will be included in the SSGM element library. PEM will be exercised by SSGM to create scenario specific background radiance maps and opacity maps which will be stored in the run-time library. Initially Version 3.3 of PEM will be installed in SSGM. The architecture will be flexible so that future PEM versions and database upgrades can be included straighforwardly in SSGM. The impact of bright nuclear backgrounds on sensors is highly dependent on the spatial and temporal structure exhibited by those backgrounds. The DNA produced STRCTR module, which modulates deterministic backgrounds with small scale temporally correlated spatial structure, has been incorporated into SSGM. STRCTR will be extended to support several of the phenomena modeled in SSGM. In the paper, high resolution examples of structured nuclear images will be shown. Also the range of nuclear burst scenarios that will be handled in the baseline SSGM will be indicated.

This poster paper will discuss the design of the Blue Airborne Targets signature (BATS) data base. A discussion of the AFEWC mission to upgrade the Infrared signature data base is included along with issues concerning the objectives of the signature data.

The emphasis of this paper is the establishment of procedures for defining Certification Criteria for the construction of surrogates, in place of the real threat, for the testing of smart weapons. The focal point of the effort is the publication of a handbook which forms the basis for the acceptance of these criteria as valid rules for the construction of surrogates. Input to the handbook will require the expertise of scientists and engineers, inside and outside of ERIM, whose understanding of various topics such as targets, sensors, modeling, and experimental investigative techniques in the laboratory and the field, need to be tapped.

The Strategic High-Altitude Radiance Code (SHARC) is a new computer code that calculates atmospheric radiation in the mesoshpere and thermosphere. The initial version, SHARC-1, is available for distribution. This talk discusses the capabilities of this code and describes the new auroral model which will be incorporated in the next version. SHARC calculates radiance and transmittance for paths from 60 to 300 km altitude in the 2-40 pm spectral region. It models radiation due to NLTE (Non-Local Thermodynamic Equilibrium) molecular emissions which are the dominant sources at these altitudes.

The ELIAS (Earth Limb Infrared Atmospheric Structure) experiment was flown from the Poker Flat Research Range, Alaska in 1983 and successfully monitored visible and infrared emissions from an IBC III+ aurora. Measure- ments were performed in both staring and scanning modes over several hundred seconds. The data for short- and mid-wave infrared regions have been analyzed in terms of auroral excitation of NO, CO2 and NO+ vibrational bands, and auroral excitation efficiencies and kinetic implications will be presented.