A Hardware-in-the-loop (HWIL) simulation facility has been successfully contributing to the development and evaluation of missiles at the 3rd Research Center, Technical Research & Development Institute, Japan Defense Agency. This facility has two main characteristics. First, it has ability to generate both various RF target and background echoes in several frequency bands. Second, it can be used for the HWIL simulation tests of missiles which have RF/IR dual mode seekers. After the outline of this facility is presented, a technique to overcome the line-of-sight (LOS) angle limitation is proposed, because LOS angle limitation is inevitable in these HWIL simulation facilities. Moreover, a simulation method for the dual mode seeker missile is shown by using this proposed simulation technique.

This paper mainly deals with the hardware-in-the-loop system developed by Beijing Simulation Center and its chief applications. A detailed description is also given herein to the major hardware-in-the-loop systems in the center.

UBM is working on autonomous vision systems for aircraft for more than one and a half decades by now. The systems developed use standard on-board sensors and two additional monochrome cameras for state estimation of the aircraft. A common task is to detect and track a runway for an autonomous landing approach. The cameras have different focal lengths and are mounted on a special pan and tilt camera platform. As the platform is equipped with two resolvers and two gyros it can be stabilized inertially and the system has the ability to actively focus on the objects of highest interest. For verification and testing, UBM has a special HWIL simulation facility for real-time vision systems. Central part of this simulation facility is a three axis motion simulator (DBS). It is used to realize the computed orientation in the rotational degrees of freedom of the aircraft. The two-axis camera platform with its two CCD-cameras is mounted on the inner frame of the DBS and is pointing at the cylindrical projection screen with a synthetic view displayed on it. As the performance of visual perception systems has increased significantly in recent years, a new, more powerful synthetic vision system was required. A single Onyx2 machine replaced all the former simulation computers. This computer is powerful enough to simulate the aircraft, to generate a high-resolution synthetic view, to control the DBS and to communicate with the image processing computers. Further improvements are the significantly reduced delay times for closed loop simulations and the elimination of communication overhead.

The advent of missile seekers with dual-mode millimeter wave and infrared common-aperture sensors has led to a requirement to develop simulation tools necessary to test these systems. Traditionally, one of the most important techniques for supporting systems development has been a full seeker hardware-in-the-loop simulation. For the past three years, U.S. Army Aviation and Missile Command (AMCOM) has been developing the simulation technologies to test these types of system in a hardware-in-the-loop environment. The dichroic beam combiner is the key component of such a facility. This paper focuses on the various dichroic beam combiner technologies that have been considered and are currently under development at AMCOM. This paper will present both experimental and analytical data to describe the performance of each technology. The basis for this paper is work performed at the AMCOM Advanced Simulation Center (ASC). The ASC is managed and operated by the Systems Simulation and Development Directorate of the Missile Research, Development, and Engineering Center, Redstone Arsenal, Alabama.

We report on the characteristics of rare earth doped chalcogenide glasses and their applicability as sources for IR scene simulation (IRSS). The characteristics of Pr³⁺- doped chalcogenide glass fiber sources and arrays operating in the MWIR region between 3 - 5 micrometer are reported. Rare earth doped chalcogenide glasses for LWIR sources are also discussed.

Various technologies have been used to achieve IR dynamic scene simulation for evaluation, testing and training for infrared imaging scene sensors. One of the most promising technologies is the use of arrays of resistively heated plates. This technology comes closest to matching the broadband IR spectra of scenes of interest to the IR sensor community. Recent advances in electronics fabrication techniques and especially in the micro-machining of silicon, are enabling arrays to be built with high pixel densities, low power requirements and reasonable cost. Characterization of these arrays is necessary to verify design models and assess process control and feasibility for applications. Reported here are measurements made on three pixel structures designs: bridge resistor, suspended membrane resistor, and post mounted membrane resistor. The bridge resistor and the suspended membrane resistor designs are prototypes; the post mounted membrane resistor is an experimental design. Measurements reported include: near field radiance distributions over the pixel areas with calculated effective fill factors, and rise and fall times in a 4 - 4.5 micrometer band; and near field and temperature measurements in the 8 - 12 micrometer band.

Resistive emitter arrays are formed via the fabrication of microemitters on Si CMOS electronics. These IR emitter arrays using microstructures have been developed at Honeywell to project scenes for a wide range of applications. A new array which has been fabricated has a size of 544 X 672 pixels. Other arrays producing very high apparent temperatures in excess of 700 K have also been fabricated. Arrays have been fabricated for projecting low background scenes achieved through cryogenic operation. All arrays are designed to project IR radiation over the full MWIR and LWIR spectral bands. Individual arrays and their emission properties will be described. Array properties at different substrate temperatures will be described. Advances in packaging of these different array types will also be discussed.

Developments are described in the design and manufacture of full 512 X 512 infra-red scene projector (IRSP) systems, as well as in a high complexity demonstrator program to realize 1024 X 1024 complexity. Design aspects include choice of drive circuit, the suspended resistor pixel design factors, the choice of busbar configurations, and the optimization of emissivity coatings. Design of the peripheral drive systems for the 512 system is outlined, and progress on manufacture reported. Development plans for the provision of suitable high complexity computer scene generation is outlined.

The MIRAGE (Multispectral Infrared Animation Generation Equipment) Dynamic Infrared Scene Projector, is a joint project developed by Santa Barbara Infrared, Inc. and Indigo Systems Corporation. MIRAGE is a complete infrared scene projector, accepting 3-D rendered analog or digital scene data at its input, and providing all other electronics, collimated optics, calibration and thermal support subsystems needed to simulated a unit under test with high-fidelity, dynamic infrared scenes. At the heart of MIRAGE is a 512 X 512 emitter array, with key innovations that solve several problems of existing designs. The read-in integrated circuit (RIIC) features 'snapshot' updating of the entire 512 X 512 resistive array, thus solving synchronization and latency problems inherent in 'rolling- update' type designs, where data is always changing somewhere on the emitter array at any given time. This custom mixed- signal RIIC also accepts digital scene information at its input, and uses on-board D/A converters and individual unit- cell buffer amplifiers to create analog scene levels, eliminating the complexity, noise, and limitations of speed and dynamic range associated with external generation of analog scene levels. The proprietary process used to create the advanced technology micro-membrane emitter elements allows a wide choice of resistor and structure materials while preserving the dissipation and providing a thermal time constant of the order of 5 ms. These innovations, along with a compact electronics subsystem based on a standard desktop PC, greatly reduce the complexity of the required external support electronics, resulting in a smaller, higher performance dynamic scene simulator system.

An analytical model is developed suitable for optimizing the choice of the design parameters that govern the extent of spatial filtering and artifact generation (aliasing) in dynamic infrared scene projection systems. The filtering and sampling processes occurring at both the scene renderer and infrared projector are examined quantitatively in such a way that they can be compared to the filtering and sampling processes occurring within the imaging infrared unit-under- test. Graphs and formulae are included that enable the optimal choice of the relevant system parameters and allow quantitative assessment of the additional sources of spatial filtering and aliasing present within the infrared projection system.

Theory and data were used to characterize apparent blackbody temperature spatial variation for a thermal emitter array and determine its dependence on sensor wavelength. The effect of inactive resistor cells was also explored. Two kinds of spatial variations are (1) nonuniformities between the operating characteristics of different thermal array cells and (2) periodic variation due to spatially varying temperature within each cell. Essential developments were (a) curves for determining how thermal effects measured in one sensor band translate to that for another spectral band, (b) analysis of measured data in a one-temperature model and a two-temperature model, and (c) quantification of a defocus remedy for decreasing contrast between inactive and active cells. It is concluded that (A) apparent blackbody temperature and spatial variations thereof are lower for high wavelengths than at 2 microns, (B) use of a uniform, one-temperature blackbody model leads to the consequence of an exaggerated effective emissivity decrease at higher wavelengths, and (C) defocus circle diameter of 1.75 times the array cell spacing promotes optimum operation. This work was performed in Eglin's Guided Weapons Evaluation Facility (GWEF).

The inherent non-uniformity of a Wideband Infrared Scene Projector (WISP) necessitates an analytical prediction of the contribution of the scene projector's non-uniformity to a test article's output image non-uniformity. A mathematical model has been developed to calculate this non-uniformity based upon a number of input parameters. The output image non-uniformity is dependent on both the non-uniformity of the scene projector and the test article, as well as a weighting factor that results from the relative contribution of the different emitters to the individual detector elements. It is through this weighting factor that parameters such as the sampling ratio, the optical blur of the emitters on the detector' focal plane array, the fill factor of the detector array, and the alignment of the emitters with respect to the detector elements affect the non-uniformity of the output image. Using this model, a theoretical limit for the maximum output image non-uniformity can be calculated for particular values of the scene projector's non-uniformity and the test article's non- uniformity. Realistic situations likely to be encountered during simulation testing were all found to be below the maximum. In order to make this model a useful tool for the laboratory environment, a computer program has been written that calculates the output image non-uniformity based on a given set of input parameters and a numerical approximation of the weighting factor.

Resistive array technology is finding increasing application in representing synthetic infrared targets and backgrounds. This paper examines the implications for resistive array calibration and radiance nonuniformity when using a NUC sensor different from the intended unit under test (UUT). Pixel-to- pixel radiance nonuniformity is the prominent noise source from resistive arrays and must be minimized for high-fidelity testing of infrared imaging sensors. We begin by analyzing three primary concerns that arise from using a NUC sensor other than the UUT: differences in responsivity and transmission of the two sensors, and the spectral emissivity of the resistive array. Because the emitters are not blackbodies, one must introduce a model of the emittance that is more complicated than Planck's function alone and involves knowledge of the emitter spectral emissivity. Sensor responsivity and transmission may further emphasize one portion of the spectral band over another. Next, we discuss how these parameters can lead to nonuniformity for the UUT even when resistive array output is perfectly calibrated for the NUC sensor. We also examine how these three parameters impact band contrast and absolute radiometry of a projected scene. We propose a method that has been used in the past to provide radiometrically accurate signals (in equivalent blackbody temperature units) to the UUT. The paper concludes by analyzing the practical side of the proposed method and establishes error bounds on the procedure as being implemented on the U.S. Army's Dynamic Infrared Scene Projector (DIRSP).

The Wideband Infrared Scene Projector (WISP) has been undergoing development for the AF Research Laboratory Kinetic Kill Vehicle Hardware-in-the-loop Simulator facility (KHILS) at Eglin AFB, FL. Numerous characterization measurements defining array dynamic range, spectral output, temporal response and nonuniformity have been performed and reported on in the past. This paper addresses the measurements and analyses performed to characterize the radiometric, spatial, and temporal noise errors induced by the array on a unit under test (UUT). An Amber camera was used as the UUT. The Amber camera spectral, spatial and radiometric response characteristics were measured. The camera spatial and temporal noises were measured by observing an extended blackbody. Similar measurements were then made on the WISP/UUT system by projecting uniform scenes. The WISP spatial and radiometric responses and the WISP-induced spatial and temporal noise were determined from the measurements. Although the measurements are unique to the UUT adopted, the WISP contribution to the system noise-equivalent temperature difference (NEDT) was determined. The spatial noise measurements provided data for validating a spatial noise model described in a companion paper. The measurements and models are useful for analyzing future measurements and predicting the impact of WISP on various test articles.

To address the many challenges that are required to support testing of state-of-the-art guided weapons the Kinetic Kill Vehicle Hardware-in-the-Loop Simulation (KHILS) facility located at Eglin AFB, FL has integrated two projector technologies into one Infrared (IR) projector. This new projector combines the capabilities of the resistor array technology with the capabilities of a non-imaging laser scanning projector (SLP) to provide KHILS with a unique testing asset. To provide representative simulations of the real world both systems will need to perform a radiometric and spatial calibration to the unit-under-test (UUT) and will need to be synchronized together. This projector was utilized to perform closed-loop hardware-in-the-loop (HWIL) testing using real-time 3D scene generation to support several test entries. Using the UUT several measurements of the projector were proposed to characterize the performance of the two technologies. This paper will report the results of these tests along with the methods used to integrate the two projectors into one system.

This paper presents mathematical models and measurements of the spatial noise a camera observes as it views a projection system with nonuniform emitter responses. The models account for the effects of the projector and camera spatial resolutions and of the alignment of the emitters with respect to the camera detectors. The models attempt to provide a better understanding of the spatial effects in a projection system and provide mathematical models for analyzing measurements and designing future hardware-in-the-loop tests. In previous work, one of the authors presented a model of the spatial, spectral, and temporal effects in a pixelized projector. In this paper, the previous model is simplified omitting the temporal effects (the scenes are assumed static). The model is then modified to describe random variations (noise) in the responses from one emitter to the next. This paper presents two different methods of modeling these effects. The first involves evaluating the spatial model directly. The second method involves performing a first order error propagation analysis on the spatial model and neglecting alignment effects. Measurements were performed to validate the models. The measurements are described in detail in a companion paper. In this paper, the spatial noise measurements are compared with model results. It was found that alignment effects were negligible, and the resulting predictions of the simplest model were in good agreement with the measured spatial noise.

For more than a decade, there has been considerable discussion about using different IR bands for the detection of low contrast military targets. Theory predicts that a target can have little to no contrast against the background in one IR band while having a discernible signature in another IR band. A significant amount of effort has been invested towards establishing hardware that is capable of simultaneously imaging in two IR bands to take advantage of this phenomenon. Focal plane arrays (FPA) are starting to materialize with this simultaneous two-color imaging capability. The Kinetic Kill Vehicle Hardware-in-the-loop Simulator (KHILS) team of the Air Force Research Laboratory and the Guided Weapons Evaluation Facility (GWEF), both at Eglin AFB, FL, have spent the last 10 years developing the ability to project dynamic IR scenes to imaging IR seekers. Through the Wideband Infrared Scene Projector (WISP) program, the capability to project two simultaneous IR scenes to a dual color seeker has been established at KHILS. WISP utilizes resistor arrays to produce the IR energy. Resistor arrays are not ideal blackbodies. The projection of two IR colors with resistor arrays, therefore, requires two optically coupled arrays. This paper documents the first demonstration of two-color simultaneous projection at KHILS. Agema cameras were used for the measurements. The Agema's HgCdTe detector has responsivity from 4 to 14 microns. A blackbody and two IR filters (MWIR equals 4.2 t 7.4 microns, LWIR equals 7.7 to 13 microns) were used to calibrate the Agema in two bands. Each filter was placed in front of the blackbody one at a time, and the temperature of the blackbody was stepped up in incremental amounts. The output counts from the Agema were recorded at each temperature. This calibration process established the radiance to Agema output count curves for the two bands. The WISP optical system utilizes a dichroic beam combiner to optically couple the two resistor arrays. The transmission path of the beam combiner provided the LWIR (6.75 to 12 microns), while the reflective path produced the MWIR (3 to 6.5 microns). Each resistor array was individually projected into the Agema through the beam combiner at incremental output levels. Once again the Agema's output counts were recorded at each resistor array output level. These projections established the resistor array output to Agema count curves for the MWIR and LWIR resistor arrays. Using the radiance to Agema counts curves, the MWIR and LWIR resistor array output to radiance curves were established. With the calibration curves established, a two-color movie was projected and compared to the generated movie radiance values. By taking care to correctly account for the spectral qualities of the Agema camera, the calibration filters, and the diachroic beam combiner, the projections matched the theoretical calculations. In the near future, a Lockheed- Martin Multiple Quantum Well camera with true two-color IR capability will be tested.

An advanced sensor test facility, located at Arnold Engineering Development Center (AEDC) has been designed for sensor calibration and performance characterization of advanced infrared sensors for strategic and tactile systems. During the past few years a sensor test facility, known as the 7V Chamber, has been used to support the Army's Interceptor Programs. This chamber complements other focal-plane-array and sensor-test capabilities developed at AEDC to provide ground test support for strategic and tactical sensor systems. The 7V Chamber is a state-of-the-art cryo-vacuum facility providing calibration and high-fidelity mission simulation using complex backgrounds and targets. This paper describes a validation effort for determining the point spread function (PSF) and corresponding wavefront errors. A method is described for measuring a highly under-sampled PSF and determining the corresponding wavefront error. This method employs a knife- edge distribution inversion of Bessel-distributed densities with a Gaussian approximation to implement a nonlinear least- squares functional fit using a Levenberg-Marquardt method.

Techniques and tools for validation of real-time infrared target signature models are presented. The model validation techniques presented in this paper were developed for hardware-in-the-loop (HWIL) simulations at the U.S. Army Missile Command's Research, Development, and Engineering Center. Real-time target model validation is a required deliverable to the customer of a HWIL simulation facility and is a critical part of ensuring the fidelity of a HWIL simulation. There are two levels of real-time target model validation. The first level is comparison of the target model to some baseline or measured data which answers the question 'are the simulation inputs correct?' The second level of validation is a simulation validation which answers the question 'for a given target model input are the simulation hardware and software generating the correct output?' This paper deals primarily with the first level of target model validation.

The Composite Hardbody and Missile Plume (CHAMP) program is a computer simulation used to provide time dependent high- fidelity infrared (IR) simulations of airborne vehicles. CHAMP computational algorithms are based on first principle physics that compute hardbody and exhaust plume radiation (absorption, emission, and reflection) for arbitrary vehicle operational state, position, orientation and atmospheric condition. All computations are performed as a function of time to allow complex vehicle dynamics to be simulated. Image processing functions are included to generate anti-aliased focal plane imagery. CHAMP can be utilized to simulate post-boost vehicle, re-entry vehicle, boost missile, theater missile, cruise missile, aircraft, and helicopter applications. CHAMP development is sponsored by the Kinetic Kill Vehicle Hardware- In-the-Loop Simulator (KHILS) facility at Eglin AFB, Florida. CHAMP is routinely utilized by KHILS to support on-going hardware-in-the-loop testing of IR seekers. Many of these tests are complex and diversified. CHAMP has been structured to support these tests by employing current generation object oriented design methodologies that facilitate adaptation to specific test requirements.

Realistic backgrounds are necessary to support high fidelity hardware-in-the-loop testing. Advanced avionics and weapon system sensors are driving the requirement for higher resolution imagery. The model-test-model philosophy being promoted by the T&E community is resulting in the need for backgrounds that are realistic or virtual representations of actual test areas. Combined, these requirements led to a major upgrade of the terrain database used for hardware-in-the-loop testing at the Guided Weapons Evaluation Facility (GWEF) at Eglin Air Force Base, Florida. This paper will describe the process used to generate the high-resolution (1-foot) database of ten sites totaling over 20 square kilometers of the Eglin range. this process involved generating digital elevation maps from stereo aerial imagery and classifying ground cover material using the spectral content. These databases were then optimized for real-time operation at 90 Hz.

As cost becomes an increasingly important factor in the development and testing of Infrared sensors and flight computer/processors, the need for accurate hardware-in-the- loop (HWIL) simulations is critical. In the past, expensive and complex dedicated scene generation hardware was needed to attain the fidelity necessary for accurate testing. Recent technological advances and innovative applications of established technologies are beginning to allow development of cost-effective replacements for dedicated scene generators. These new scene generators are mainly constructed from commercial-off-the-shelf (COTS) hardware and software components. At the U.S. Army Aviation and Missile Command (AMCOM) Missile Research, Development, and Engineering Center (MRDEC), researchers have developed such a dynamic IR scene generator (IRSG) built around COTS hardware and software. The IRSG is used to provide dynamic inputs to an IR scene projector for in-band seeker testing and for direct signal injection into the seeker or processor electronics. AMCOM MRDEC has developed a second generation IRSG, namely IRSG2, using the latest Silicon Graphics Incorporated (SGI) Onyx2 with Infinite Reality graphics. As reported in previous papers, the SGI Onyx Reality Engine 2 is the platform of the original IRSG that is now referred to as IRSG1. IRSG1 has been in operation and used daily for the past three years on several IR projection and signal injection HWIL programs. Using this second generation IRSG, frame rates have increased from 120 Hz to 400 Hz and intensity resolution from 12 bits to 16 bits. The key features of the IRSGs are real time missile frame rates and frame sizes, dynamic missile-to-target(s) viewpoint updated each frame in real-time by a six-degree-of- freedom (6DOF) system under test (SUT) simulation, multiple dynamic objects (e.g. targets, terrain/background, countermeasures, and atmospheric effects), latency compensation, point-to-extended source anti-aliased targets, and sensor modeling effects. This paper provides a comparison between the IRSG1 and IRSG2 systems and focuses on the IRSG software, real time features, and database development tools.

An approach to utilize the symmetric multiprocessing environment of the Silicon Graphics Inc.^R (SGI) Onyx2^TM has been developed to support the generation of IR/EO scenes in real-time. This development, supported by the Naval Air Warfare Center Aircraft Division (NAWC/AD), focuses on high frame rate hardware-in-the-loop testing of multiple sensor avionics systems. In the past, real-time IR/EO scene generators have been developed as custom architectures that were often expensive and difficult to maintain. Previous COTS scene generation systems, designed and optimized for visual simulation, could not be adapted for accurate IR/EO sensor stimulation. The new Onyx2 connection mesh architecture made it possible to develop a more economical system while maintaining the fidelity needed to stimulate actual sensors. An SGI based Real-time IR/EO Scene Simulator (RISS) system was developed to utilize the Onyx2's fast multiprocessing hardware to perform real-time IR/EO scene radiance calculations. During real-time scene simulation, the multiprocessors are used to update polygon vertex locations and compute radiometrically accurate floating point radiance values. The output of this process can be utilized to drive a variety of scene rendering engines. Recent advancements in COTS graphics systems, such as the Silicon Graphics InfiniteReality^R make a total COTS solution possible for some classes of sensors. This paper will discuss the critical technologies that apply to infrared scene generation and hardware-in-the-loop testing using SGI compatible hardware. Specifically, the application of RISS high-fidelity real-time radiance algorithms on the SGI Onyx2's multiprocessing hardware will be discussed. Also, issues relating to external real-time control of multiple synchronized scene generation channels will be addressed.

The emergence of sensor systems which detect ultraviolet missile signatures defines the need for an ultraviolet environment simulation capability. This paper discusses the development of a real-time hardware-in-the-loop testing capability for ultraviolet missile warning receiver systems. The requirements for real-time ultraviolet simulation will be defined and a real-time architecture which addresses these requirements is presented. The requirements and real-time architecture address the modeling of ultraviolet sensor characteristics and ultraviolet phenomenology. Specific issues which will be addressed include ultraviolet sensor system characteristics, ultraviolet source signature modeling, atmospheric off-axis spatial scatter modeling through the use of the Off-Axis Scattered Intensity Calculation (OSIC) code, and the simulation of these effects in a real-time scene rendering environment. Particular emphasis is placed on the refinement of a lookup table for the OSIC code and consideration for the use of the MSIG ultraviolet missile signature database. Also discussed is the real-time hardware- in-the loop architecture developed for testing of the Common Missile Warning System. This work was performed to support the test and evaluation of modern missile warning systems at Wright Labs Integrated Defense Avionics Lab.

Real-time infrared (IR) scene generation for Hardware-in-the- Loop (HWIL) testing of IR seeker systems is a complex operation. High frame rates and high image fidelity are required to properly evaluate a seeker system's designation, identification, tracking, and aim-point selection tasks. Rapidly improving Commercial-off-the-Shelf (COTS) scene generation hardware has become a viable solution for HWIL test activities conducted at the Kinetic Kill Vehicle Hardware-in- the-Loop Simulator (KHILS) facility at Eglin AFB, Florida. A real-time IR scene generation implementation for a complete closed-loop guided missile simulation test entry was accomplished at KHILS. The scenarios used for the simulation were Theater Missile Defense (TMD) exo-atmospheric hit-to-kill intercepts of a re-entry target. Innovative scene generation techniques were devised to resolve issues concerning scene content and rendering accuracy while maintaining the required imaging frame rate. This paper focuses on the real-time scene generation requirements, issues, and solutions used for KHILS test entries.

Development and generation of high-fidelity IR scenes to support testing requirements at the Kinetic Kill Vehicle Hardware-in-the-Loop Simulator (KHILS) facility at Eglin AFB, Florida has been the mission for the Air Force Research Laboratory's (AFRL) scene generation team throughout the past ten years. During that time scene generation efforts have supported operational scenarios ranging from surveillance through terminal homing. Recent programs have required the development of IR target and background models to support the testing needs of a high-speed fuze. Development of IR models and techniques to support high-speed fuze applications required advancing the state-of-the-art in IR scene generation. This effort required the development of several target models not available from other sources. In addition, due to the unusual proximity fuze seeker configuration that utilizes a wide angle lens to encompass a full 360 degree field-of-view (FOV) and very fast frame rate requirements, normal scene generation techniques were not adequate. Hundreds of scenarios consisting of hundreds of image frames were needed to develop the fuzing algorithms. This scene generation requirement necessitated that realistic scene sequences be produced in minutes rather than hours. This paper discusses the IR model development path to generate IR scene sequences to support the algorithm development for this fuzing program. The discussion describes the process and unique modeling techniques that were implemented to build foreign target models that include fighter and bomber aircraft, low-flying cruise missiles, and helicopters. Implementation of appropriate rendering techniques to support the generation of backgrounds that include atmospherics, terrain, and sea for realistic target engagements are also discussed. Finally, a description of the process utilized in merging IR model and commercial hardware solutions to satisfy the IR scene generation requirements for this program is presented.

A computer program has been developed to provide closed-loop infrared imagery of composite targets and backgrounds in real- time. This program operates on parametric databases generated off-line by computationally intensive first principle physics codes such as the Composite Hardbody and Missile Plume (CHAMP) program, Synthetic Scene Generation Model (SSGM), and Multi- Spectral Modeling and Analysis (MSMA/Irma program. The parametric databases allow dynamic variations in flight and engagement scenarios to be modeled as closed-loop guidance and control algorithms modify the operational dynamics. The program is tightly coupled with the parametric databases to produce infrared radiation results in real-time and OpenGL graphic libraries to interface with high performance graphic hardware. The program is being sponsored for development by the Kinetic Kill Vehicle Hardware-in-the-Loop Simulator facility of the Air Force Research Laboratory Munitions Directorate located at Eglin AFB, Florida.

In hardware-in-the-loop (HWIL) testing of infrared and electro-optical (IR/EO) sensor systems, stimulation of the unit under test (UUT) is achieved through either the projection of in-band scene radiance into the sensor's optical aperture or injection of the signals into the system's processing electronics. The injection of a signal representing the IR/EO scene into the electronics of the UUT requires an interface to translate the computer generated scene into the appropriate format for processing by the signal processing electronics. Likewise, the optical scene projection requires a pre-processing interface to translate the computer generated scene into the appropriate format for the optical projection system. Although the development of unique direct injection and optical projection interfaces can meet testing requirements, the effort can be costly, time consuming, and largely redundant from system to system. In order to provide the testing community with a configurable consumer-off-the- shelf (COTS) solution to address the unique emulation and interfacing problem of HWIL test facilites, Amherst Systems, under contract to the Air Force Flight Test Center (AFFTC) at Edwards Air Force Base, has developed the Universal Programmable Interface (UPI). In this paper, the UPI solution for HWIL interfacing will be reviewed. First, the requirements for the UPI system will be detailed. Next, the functional and performance capabilities of the UPI system will be described. Finally, the UPI hardware and software design and architecture will be discussed.

Many test facilities currently have the requirement to project dynamic, infrared (IR) imagery into sensors under test. This imagery must be of sufficient quality and resolution so that, sensors under test will perceive and respond just as they do to real-world scenes. In order to achieve this fidelity from an infrared micro-resistor based emitter array, Non-Uniformity Correction (NUC) is necessary. An important step in performing NUC is to calibrate the IR projection system so as to be capable of projecting a uniform temperature/IR image. The quality of the projected image is significantly enhanced by proper application of this calibration. To properly implement non-uniformity correction, it is necessary to accurately measure the IR emissions of each display element, or display pixel (dixel), in the emitter array. Performing these measurements involves collecting a large volume of data at a high rate. The U.S. Army's Test and Evaluation Command (TECOM) has developed a high-speed, relatively inexpensive and flexible means of digitally capturing IR emissions from an emitter array. This method of digitally capturing IR imagery is also useful in performing sensor and overall system characterization. TECOM has investigated, planned, and developed a non-uniformity data collection system, using primarily Commercial Off-The-Shelf (COTS) hardware and software, capable of digitally capturing the emissions of a long wave IR emitter array at 30 frames per second. The digital images are then processed to characterize individual dixels of the IR scene projection system. This paper presents a description of a test facility's need, along with a history of the design, development and actual implementation of a non- uniformity data collection system. In addition to the primary purpose of collecting digital imagery for NUC, other system uses for digital imagery collection are discussed.

Hardware-in-the-loop (HWIL) testing of infrared missile seekers has been a proven method for seeker evaluation for many years. Infrared HWIL testing has two primary modes, projection or injection. With infrared projection HWIL testing, the seeker's optics and detectors are retained as part of the simulation since an infrared scene in the correct waveband is presented to the seeker's optics, and is then detected and processed. When using the injection mode of HWIL testing the infrared scene is injected directly into the seeker's electronics and bypasses the imaging and detection process. When this type of simulation is used it is critical to model the optical and electrical processes that would have degraded the image in a real-world scenario. Real-time modeling of sensor system modulation transfer functions and other forms of image degradation is a computationally intensive task. The types of calculations necessary for real- time sensor modeling often push the processing requirements past the capabilities of standard processors and custom processing hardware is required. This paper discusses solutions to this problem that have been implemented for infrared seekers at the U.S. Army's Aviation and Missile Command's, Missile Research, Development, and Engineering Center.

Providing a flexible and reliable source of IR target imagery is absolutely essential for operation of an IR Scene Projector in a hardware-in-the-loop simulation environment. The Kinetic Kill Vehicle Hardware-in-the-Loop Simulator (KHILS) at Eglin AFB provides the capability, and requisite interfaces, to supply target IR imagery to its Wideband IR Scene Projector (WISP) from three separate sources at frame rates ranging from 30 - 120 Hz. Video can be input from a VCR source at the conventional 30 Hz frame rate. Pre-canned digital imagery and test patterns can be downloaded into stored memory from the host processor and played back as individual still frames or movie sequences up to a 120 Hz frame rate. Dynamic real-time imagery to the KHILS WISP projector system, at a 120 Hz frame rate, can be provided from a Silicon Graphics Onyx computer system normally used for generation of digital IR imagery through a custom CSA-built interface which is available for either the SGI/DVP or SGI/DD02 interface port. The primary focus of this paper is to describe our technical approach and experience in the development of this unique SGI computer and WISP projector interface.

As scene generator platforms begin to rely specifically on commercial off-the-shelf (COTS) hardware and software components, the need for high speed programmable personality interfaces (PPIs) are required for interfacing to Infrared (IR) flight computer/processors and complex IR projectors in the hardware-in-the-loop (HWIL) simulation facilities. Recent technological advances and innovative applications of established technologies are beginning to allow development of cost effective PPIs to interface to COTS scene generators. At the U.S. Army Aviation and Missile Command (AMCOM) Missile Research, Development, and Engineering Center (MRDEC) researchers have developed such a PPI to reside between the AMCOM MRDEC IR Scene Generator (IRSG) and either a missile flight computer or the dynamic Laser Diode Array Projector (LDAP). AMCOM MRDEC has developed several PPIs for the first and second generation IRSGs (IRSG1 and IRSG2), which are based on Silicon Graphics Incorporated (SGI) Onyx and Onyx2 computers with Reality Engine 2 (RE2) and Infinite Reality (IR/IR2) graphics engines. This paper provides an overview of PPIs designed, integrated, tested, and verified at AMCOM MRDEC, specifically the IRSG2's PPI.

Holographic Interferometry as been successfully employed to characterize the materials and behavior of diverse types of structures under stress. Specialized variations of this technology have also been applied to define dynamic and vibration related structural behavior. Such applications of holographic technique offer some of the most effective methods of modal and dynamic analysis available. Real-time dynamic testing of the modal and mechanical behavior of aerodynamic control structures for advanced missiles systems has always required advanced instrumentation for data collection in either actual flight test or wind-tunnel simulations. Advanced optical holography techniques are alternate methods when define actual behavioral data on the ground in a nondestructive Hardware-in-the-loop environment. These methods offer significant insight in both the development and subsequent operational test and modeling of advanced composite control structures and their integration with total vehicle system dynamics. Structures and materials can be analyzed with very low amplitude excitation and the resultant data can be used to adjust the accuracy of mathematically derived structural models. Holographic Interferometry offers a powerful tool to aid in the primary engineering and development of advanced graphite-epoxy fiber composite materials for use in advanced aerodynamic platforms. Aircraft, missile, and smart weapon control structure applications must consider environments where extremes in vibration and mechanical stresses can affect both operation and structural stability. These are ideal requisites for unlaces using advanced holographic methods in the initial design and subsequent test of such advanced components. Holographic techniques are nondestructive, real-time, and definitive in allowing the identification of vibrational modes, displacements, and motion geometries. Holographic analysis is also directly indicative of various types of induced mechanical, thermal, and acoustic structural stress related to hidden structural anomalies and defects. Deriving such information can be crucial to the determination of mechanical configurations and designs, as well as critical operational parameters of structures composed of advanced engineering materials.

The KHILS facility in the Air Force Research Laboratory (AFRL) Munitions Directorate at Eglin AFB has developed a hardware- in-the-loop (HIL) simulation for the Low Cost Autonomous Attack System (LOCAAS). This simulation was developed to provide risk reduction for the LOCAAS guided test vehicle (GTV) flight test program. This paper reports on the results of this support activity and describes the simulation techniques employed to enable real-time closed-loop testing of the LOCAAs Laser Radar (LADAR) concept. The overall HIL layout will be described, including a discussion of interfaces, transport delays associated with these interfaces, compensation techniques employed to minimize the effects of these interface delays, real-time 3-D LADAR scene generation, and flight motion simulation.

The Infrared Simulation and Test Acceptance Facility (IR STAF) will be a state-of-the-art hardware-in-the-loop (HWIL) simulation/test facility for performing all-up-round missile testing in a non-destructive laboratory environment. Full-up IR guided missiles will be placed on a five-axis flight motion simulator (FMS) to allow closed-loop testing of the missile for the full range of tactical flight scenarios. This paper focuses on the unique requirements placed on the FMS, and the design trade-offs that led to performance parameters that could meet mission requirements. The inner three axes of the FMS carries the all-up-round missile under test and the outer two axes move a dynamic IR scene projector system. A real-time control computer simulates the aerodynamic and kinematics response of the missile and generates commands for the FMS and IR scene projector. This system puts the missile under test through multiple scenarios as opposed to a single live-firing. Non-destructive HWIL testing can reduce the number of live firings during lot acceptance tests (LATs) while verifying system performance with a high degree of confidence. The purpose of the facility is to substantially reduce the cost of missile lot acceptance testing while maintaining or improving the confidence in missile hardware.

All hardware-in-the-loop (HWIL) missile simulations use motion platforms that position the missile seeker and simulated target to relative positions and motions that reproduce a live engagement. These motion platforms are usually called Flight Motion Simulators (FMS). Real-time control computers manage the engagement by simulating the aerodynamic and kinematic responses the missile anticipates, and commanding the missile and target motions to simulate the engagement. The advantages of this technique over live firings are well known: shorter development time, reduced development cost, greater variety in the test scenarios, and generation of objective, measurable, and repeatable criteria for subsystem and system evaluation. This paper focuses on the history of the FMS used in HWIL missile testing and the current applications of these systems. Systems with up to nine axes of rotary motion have been developed for infrared missile seeker simulation, and large target positioning systems have been deployed for RF and point IR target movement. As digital computers have become more powerful and semiconductor infrared scene generation systems developed, new demands have been placed on the FMS. Several of these applications are described. The use of aeroload simulators to study the response of missile aerodynamic control surfaces is also briefly described.

This paper describes recent developments and the current status of the Laser Diode Array Projector (LDAP) Technology. The LDAP is a state-of-the-art dynamic infrared scene projector system capable of generating high resolution in-band infrared imagery at high frame rates. Three LDAPs are now operational at the U.S. Army Aviation and Missile Command's (AMCOM) Missile Research, Development, and Engineering Center (MRDEC). These projectors have been used to support multiple Hardware-in-the-Loop test entries of various seeker configurations. Seeker configurations tested include an InSb 256 X $256 focal-plane array (FPA), an InSb 512 X 512 FPA, a PtSi 640 X 480 FPA, a PtSi 256 X 256 FPA, an uncooled 320 X 240 microbolometer FPA, and two dual field- of-view (FOV) seekers. Several improvements in the projector technology have been made since we last reported in 1997. The format size has been increased to 544 X 544, and 672 X 512, and it has been proven that the LDAP can be synchronized without a signal from the unit-under test (UUT). The control software has been enhanced to provide 'point and click' control for setup, calibration, image display, image capture, and data analysis. In addition, the first long-wave infrared (LWIR) LDAP is now operational, as well as a dual field of view LDAP which can change its FOV within 0.25 seconds. The projector is interfaced to a Silicon Graphics scene generation computer which is capable of real-time 3-D scene generation. Sample images generated with the projector and captured by an InSb FPA sensor are included in the text.

We describe incremental improvements in measurement, understanding and control of sensor-perceived scene accuracy factors for BAe resistor-array IR scene projector devices by means of system and device design, analysis and measurement methodology. Progress has been made in the areas of fill- factor measurement, aliasing effects, dead pixel statistics, image spreading, the design of non-uniformity correction (NUC) systems, busbar robbing, heatsink effects and noise sources.

A multi-band infrared plume simulator (MIPS) system capable of projecting light from three spectrally separate, dynamic infrared (IR) sources has been developed by the Defense Special Weapons Agency (DSWA) and Mission Research Corporation (MRC). The purpose of this system is to provide long-wave IR (LWIR) movies of bomb explosions for a forward looking IR (FLIR), and high power pulses of medium-wave IR (MWIR) light to simulate the radiance intensity from the plumes in two bands for a non-imaging radiometer. The FLIR and two-color radiometer are detectors in the new Tactical FLIR Pod Modification (TFPM). The LWIR movies are generated with a DSWA Nuclear Optical Dynamic Display System (NODDS) 512 X 512 suspended membrane emitter array. The MWIR plume signatures are generated with two lead-salt laser diodes. The emitter array supplies the 8 micrometer to 12 micrometer, time-varying images with peak apparent temperatures of about 350 K. The two laser diodes, one emitting at 4.6 micrometer and the other at 3.8 micrometer, supply the higher power signals to simulate greater than 1000 K plumes for the two-color radiometer. The design of the MIPS is based on the design of the TFPM and the TFPM is based on the results from the Dipole Pride test series, so this paper will review the Dipole Pride results and the TFPM specifications in addition to examining the operation of the MIPS.

A greater awareness of and increased interest in the use of modeling and simulation (M&S) has been demonstrated at many levels within the Department of Defense (DoD) and all the Armed Services agencies in recent years. M&S application is regarded as a viable means of lowering the life cycle costs of theater missile defense (TMD) weapon system acquisition beginning with studies of new concepts of warfighting through user training and post-deployment support. The Missile Research, Engineering, and Development Center (MRDEC) of the U.S. Army Aviation and Missile Command (AMCOM) has an extensive history of applying all types of M&S to TMD weapon system development and has been a particularly strong advocate of hardware-in-the-loop (HWIL) simulation for many years. Over the past 10 years MRDEC has developed specific and dedicated HWIL capabilities for TMD applications in both the infrared and radio frequency sensor domains. This paper provides an overview of the infrared-based TMD HWIL missile facility known as the Imaging Infrared System Simulation (I²RSS) which is used to support the Theater High Altitude Air Defense (THAAD) missile system. This facility uses M&S to conduct daily THAAD HWIL missile simulations to support flight tests, missile/system development, independent verification and validation of weapon system embedded software and simulations, and missile/system performance against current and future threat environments. This paper describes the THAAD TMD HWIL role, process, major components, HWIL verification/validation, and daily HWIL support areas in terms of both missile and complete system.

The Wideband Infrared Scene Projector (WISP) was developed to project dynamic, detailed scenes to imaging infrared (IR) missile seekers. However, the vast majority of IR seekers currently in inventory are nonimaging and pseudo-imaging reticle-based seekers. Air Force Research Laboratory's (AFRL) Dynamic Infrared Missile Evaluator (DIME) Facility is interested in the response of these conventional seekers to detailed IR scenes, as would be encountered in the final phase of a missile engagement. Conventional seekers have different scene projection requirements than the imaging seekers for which the WISP was designed. To assess the applicability of an IR scene projector for testing conventional seekers, DIME Facility personnel used two reticle-based seekers to measure spatial and temporal characteristics of the WISP. A description of the testing performed and the results obtained are presented in this paper.