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 missile defense and tactical missile weapon system acquisition beginning with studies of new concepts of war-fighting through user training and post-deployment support. The Aviation and Missile Research, Engineering, and Development Center (AMRDEC) of the U.S. Army Aviation and Missile Command (AMCOM) has an extensive history of applying all types of M&S to weapons system development and has been a particularly strong advocate of hardware-in-the-loop (HWIL) simulation and test for many years. Over the past 40 years AMRDEC has developed and maintained the Advanced Simulation Center (ASC) which provides world-class, high fidelity, specific and dedicated HWIL simulation and test capabilities for the Army's missile defense and tactical missile program offices in both the infrared and radio frequency sensor domains. The ASC facility uses M&S to conduct daily HWIL missile simulations and tests 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 ASC role, recaps the past year, describes the HWIL components and advancements, and outlines the path-ahead for the ASC in terms of both missile and complete system HWIL simulations and test with a focus on the imaging infrared systems.

The U.S. Army Aviation and Missile Command (AMCOM) Advanced Simulation Center (ASC) provides hardware-in-the-loop (HWIL) simulation support to Program Executive Officers (PEO) and Project Managers (PM) who are responsible for developing and fielding precision guided missiles and sub-munitions for the U.S. Army. The ASC is also engaged in cooperative HWIL simulation tasks supporting other Armed Service Agencies, NATO and other U.S. allies. HWIL simulation provides a means of exercising missile guidance and control hardware in simulated flight, wherein the missile sensors are stimulated with input signals which make the system behave as though it were in actual operation. Real-time computers are used to control the target and countermeasure signatures and battlefield scenarios. Missile flight dynamics, responding to the commands issued by the guidance and control system hardware/software, are simulated in real-time to determine the missile trajectory and to calculate target intercept conditions. The ASC consists of 10 HWIL simulation facilities developed over a period of 20 years. These facilities contain special purpose infrared and RF signal generation equipment, flight motion simulators, radiation chambers, optics, and computers. They provide in- band target signatures, countermeasures, and background scenarios in the microwave, millimeter wave, infrared and visible regions of the electromagnetic spectrum. The ASC HWIL simulation facilities are an important source of test and evaluation data and have a critical role in all phases of a missile system life cycle. The development of a new generation of missile systems that use multi-spectral seekers has imposed unique and difficult requirements on ASC HWIL simulation facilities. For the past three years, the U.S. Army Aviation and Missile Command (AMCOM) has been developing a HWIL simulation facility to test common aperture multi-spectral missile seekers. This paper discusses the problems encountered during the development of this facility, the solutions, and the resulting capability of this unique HWIL simulation facility.

A new imaging infrared hardware-in-the-loop (HWIL) simulation laboratory has been added to the already rich set of HWIL assets at the U.S. Army Aviation and Missile Command (AMCOM) for evaluation of weapons systems with infrared seekers. This paper provides a system description of the new laboratory, the Imaging Infrared Simulation System III (IIRSS3), and discusses the application of the facility to two different weapon systems.

Testing advanced weapons systems, like the Comanche helicopter, has always presented technical challenges to the Test and Evaluation (T&E) community. Because these weapon systems are on the cutting edge of technology, it is the tester's responsibility to develop the tools and techniques to fully exercise a new weapon system's capability. As with most testing, state-of-the-art tools which provide test stimuli that matches or exceeds the fidelity of the systems under test must be developed. One such tool under development to test FLIR senors is the Mobile Infrared Scene Projector (MIRSP). This paper will investigate current plans to support the T&E of the Comanche FLIR sensor during SIL testing. Planning the T&E usage of the MIRSP has involved identifying limitations, both in hardware and software, and determining how to minimize the effects of these limitations or proposing solutions to correct these limitations. The final result of this effort is to maximize the operational effectiveness of the MIRSP in order to benefit T&E of all FLIR sensors in the future.

This paper details a Hardware-in-the-Loop Facility (HIL) developed for evaluation and verification of a missile system with dual mode capability. The missile has the capability of tracking and intercepting a target using either an RF antenna or an IR sensor. The testing of a dual mode system presents a significant challenge in the development of the HIL facility. An IR and RF target environment must be presented simultaneously to the missile under test. These targets, simulated by IR and RF sources, must be presented to the missile under test without interference from each other. The location of each source is critical in the development of the HIL facility. The requirements for building a HIL facility with dual mode capability and the methodology for testing the dual mode system are defined within this paper. Methods for the verification and validation of the facility are discussed.

This paper describes a hardware-in-the-loop (HWIL) system developed for testing Radio Frequency (RF), Infra-Red (IR), and Dual-Mode missile seekers. The system consists of a unique hydraulic five-axis (three seeker axes plus two target axes) Flight Motion Table (FMT), an off-axis parabolic reflector, and electronics required to generate the signals to the RF feeds. RF energy that simulates the target is fed into the reflector from three orthogonal feeds mounted on the inner target axis, at the focal point area of the parabolic reflector. The parabolic reflector, together with the three RF feeds (the Compact Range), effectively produces a far-field image of the target. Both FMT target axis motion and electronic control of the RF beams (deflection) modify the simulated line-of-sight target angles. Multiple targets, glint, multi-path, ECM, and clutter can be introduced electronically. To evaluate dual-mode seekers, the center section of the parabolic reflector is replaced with an IR- transparent, but RF-reflective section. An IR scene projector mounts to the FMT target axes, with its image focused on the intersection of the FMT seeker axes. The system eliminates the need for a large anechoic chamber and 'Target Wall' or target motion system used with conventional HWIL systems. This reduces acquisition and operating costs of the facility.

The essential benefit of Hardware-in-the-loop (HWIL) simulation can be summarized as that the performance of missile guidance/control system is evaluated realistically without the modeling error by using actual hardware such as seeker systems, autopilot systems and servo equipments. HWIL simulation, however, requires very expensive facilities: in these facilities, target model generators are indispensable subsystems. In this paper, a target model generator for RF/IR seeker systems is introduced, and then, two technical problems with this facility are discussed: a method to overcome the line-of-sight (LSO) angle limitation and the RF/IR dual mode seeker simulation technique.

A realtime hardware-in-the-loop simulation facility for a multimode sensor is in use at the U.S Army Aviation and Missile Command's Advanced Simulation Center. The purpose of this facility is to simulate battlefield scenarios and generate performance data vital to the development and testing of such a system. The simulation has proven to be a cost- effective alternative to live-fire field tests and a valuable tool for performing engineering studies. A plan for verifying and validating the simulation has been developed and is currently being executed. The paper describes the simulation facility's role in the development and testing of a multimode sensor. Also presented are the simulation theory of operation and the target and environmental modeling methodologies employed in the laboratory. Finally, the simulation verification and validation (V&V) plan is outlined. In particular, the major challenges encountered thus far in the V&V process and the solutions devised to overcome them are described.

The Air-to-Ground Missiles Systems (AGMS) Project Management Office (PMO) chose to invest in hardware-in-the-loop (HWIL) simulation as an integral part of their Longbow/HELLFIRE (Helicopter Launched, Fire-and-Forget) Modular Missile System program throughout the development and production phases. This investment has resulted in two HWIL simulations, developed by the U.S. Army Aviation and Missile Command (AMCOM) Missile Research Development and Engineering Center, that have had unprecedented success in program support from the early development through production phases. The Millimeter Simulation System 1 (MSS-1) facility is capable of edge-of- the-envelope performance analysis and verification using high- fidelity target, background, and countermeasures signature modeling. The System Test/Acceptance Facility (STAF), developed in partnership with Redstone Technical Test Center, tests full-up missiles for production lot acceptance. Between these two facilities, HWIL simulation is responsible for pre- flight confidence testing of missile hardware and software, software independent verification and validation (IV&V) testing, comprehensive performance evaluation, component verification, production lot acceptance, and data gathering for the shelf life extension program. One payoff of the MSS-1 HWIL investment has been an extremely effective flight test program with MSS-1 receiving credit for saving three flight tests and documenting over 40 failure modes. With the advent of the Performance Based Specification, the MSS-1 has become involved in continuous verification of high level specifications since contractor controlled, low-level specifications are subject to change. The STAF has saved 8 million annually through providing a non-destructive lot acceptance-testing paradigm, and further benefited the production phase by discovering three production problems. This paper will highlight the innovative uses of HWIL simulation as utilized in the Longbow/HELLFIRE program and document the successes demonstrated as this program has transitioned from development into the production phases.

CMOS/MEMS is used as a technique to create infrared emitters. A commercial CMOS process is used that, with a post-processing silicon etch, creates thermally isolated, electronically addressable polysilicon resistors suitable for infrared scene generation. Previous efforts have focused on 2.0 micron CMOS processes which require large suspended structures in order to accommodate the design rules. This work has successfully used a 1.2 micron commercial process with a post-processing silicon etch to scale down the emitter structure to 40 X 40 microns. This allows higher density arrays, and together with using the high value poly resistor available in the 1.2 micrometer process, allows lower current operation, significantly relaxing the design constraints previously encountered. A 128 X 128 design was fabricated in this process and is characterized using a microradiometer. A silicon-on-insulator thermal pixel array design with a further reduction in emitter dimensions is also presented.

To enhance the fidelity of numerical flow field (plume) imagery in hardware-in-the-loop (HIL) systems, new methods using particle system graphics have been developed. To render infrared (IR) images that are consistent with the underlying physical phenomenology, techniques for particle placement, pixel rasterization and drawing were developed and implemented in computer software. The software was integrated into an existing HIL scene generator and used to demonstrate several new capabilities. Moving particle systems were used to depict the internal flow and turbulence common to plumes. Persistent particle systems were used to depict the trail of hot gas and particulates left behind typical plumes. The addition of plume dynamic behaviors such as these can potentially improve HIL systems and, as a result, improve the testing of seekers and other weapon systems.

New computing architectures based on the DIME standard have been previously introduced which allow for processing of high frame rate imaging systems which may also need low latency capability, a common requirement for HWIL systems. This paper is presented in two sections: To achieve future realism in image generation systems for hardware-in-the-loop (HWIL) testing a significant increase in processing power is required, but additionally a suitable architecture is essential to provide low latency response on the data flow. Nallatech previously introduced DIME as a novel platform for HWIL systems which is capable of handling sub-frame latencies and greater than 100 Hz frame rates. We will demonstrate the system operating on traditional complex imaging problems, such as large convolution masks of 13 X 13 and also on new image generation techniques such as the particle method which is being developed by Matra British Aerospace Dynamics UK (MBDUK). MBDUK are proceeding on upgrading existing HWIL image generation systems for real-time particle models, to higher frame rates and increased complexity. Using Nallatech's latest DIME based architectures, models containing thousands of individual particles can be created at frame rates over 100 Hz and a resolution of 1024 X 1024 oversampled 4 times. This is possible because particle models exhibit high levels of parallelism ideal for exploiting the architecture of an FPGA. This paper will demonstrate the versatility of these particle models to create highly realistic signatures in terms of spatial dynamics and IR signature. Particle models are ideal for simulating dynamic objects such as flares, exhaust plumes, fires and explosions.

This paper describes advances in the development of IR/EO scene generation to support the Infrared Sensor Stimulator system (IRSS) which will be used for installed system testing of avionics electronic combat systems. The IRSS will provide a high frame rate, real-time, reactive, hardware-in-the-loop test capability for the stimulation of current and future infrared and ultraviolet based sensor systems. Scene generation in the IRSS is provided by an enhanced version of the Real-time (IR/EO Scene Simulator (RISS) which was previously developed by Comptek Amherst Systems. RISS utilizes the symmetric multiprocessing environment of the Silicon Graphics^R Onyx2^TM to support the generation of IR/EO scenes in real-time. It is a generic scene generation system which can be programmed to accurately stimulate a wide variety of sensors. Significant advancements have been made in IRSS capabilities in the past year. This paper will discuss the addition of new simulation techniques which have been added to the system to better support the high resolution, geospecific testing requirements of a new generation of imaging sensors. IRSS now better supports the use of high resolution databases which contain material maps at photo realistic precision. Other developments which will be discussed include extensive improvements to the database and scenario development tools, advancements in the support for multiple synchronized scene generation channels, and new support for sea and ship models.

This paper describes advances in the development IR/EO scene generation using the second generation Comptek Amherst Systems' Scene Rendering Subsystem (SRS). The SRS is a graphics rendering engine designed specifically to support real-time hardware-in-the-loop testing of IR/EO sensor systems. The SRS serves as an alternative to commercial rendering systems, such as the Silicon Graphics^R InfiniteReality, when IR/EO sensor fidelity requirements surpass the limits designed into COTS hardware that is optimized for visual rendering. The paper will discuss the need for such a system and will present examples of the kinds of sensor tests that can take advantage of the high radiometric fidelity provided by the SRS. Examples of situations where the high spatial fidelity of the InfiniteReality is more appropriate will also be presented. The paper will also review models and algorithms used in IR/EO scene rendering and show how the design of the SRS was driven by the requirements of these models and algorithms. This work has been done in support of the Infrared Sensor Stimulator system (IRSS) which will be used for installed system testing of avionics electronic combat systems. The IRSS will provide a high frame rate, real-time, reactive, hardware-in-the-loop test capability for the stimulation of current and future infrared and ultraviolet based sensor systems. The IRSS program is a joint development effort under the leadership of the Naval Air Warfare Center -- Aircraft Division, Air Combat Environment Test and Evaluation Facility (ACETEF) with close coordination and technical support from the Electronic Combat Integrated Test (ECIT) Program Office. The system will be used for testing of multiple sensor avionics systems to support the Development Test & Evaluation and Operational Test & Evaluation objectives of the U.S. Navy and Air Force.

Comptek Amherst Systems has been involved in the development of a Universal Programmable Interface (UPI) for use in hardware-in-the-loop (HWIL) testing of infrared/electro-optic (IR/EO) sensor systems. The UPI provides an interface between a scene generation system (SGS) and the unit under test (UUT) for either direct injection or optical projection. Unlike custom interfaces, the reconfigurable UPI supports a wide range of sensor systems. It was designed to simulate various sensor effects, emulate bypassed sensor components, and reformat the data for input to the UUT. This paper discusses the advances we have made in the past year on the UPI, including those in both hardware and software.

This paper describes the Sensor Emulator System developed at AMCOM using custom off the shelf image processing hardware combined with in-house designed interfaces to SGI Digital Video Port (DVP) input and output hardware. The system was designed to allow the emulation processing elements to be inserted in the image output path of the SGI computers currently being used in the Hardware-in-the-Loop (HWIL) facilities. This is accomplished by converting the SGI's DVP output to the emulator's input bus format, and after being processed, the output is converted back to DVP format. The images can then be input to in-house designed injector or projector interfaces. Sixteen bit images of 256 X 256 pixels, at frame rates of 800 Hz have been input, processed in parallel on 5 nodes, and output with this system. The system's processing elements are Matrox Genesis image processing boards. Each processing node consists of a Texas Instruments C80, a Matrox Neighborhood Operation Accelerator ASIC (NOA²) and a Matrox Video Interface ASIC (VIA). The NOA² is a multiplier/accumulator (MAC) array capable of 32 simultaneous sum of products at 50 MHz. The VIA provides high- speed links between acquisition, processing and display devices by controlling multiple independent 32 bit wide busses. It controls the image acquisition and fan-out to the processing Nodes and output without adding overhead. The C80 provides the processing for sensor electronic functions such as gains, offsets, dead pixels, saturation, etc. This combination has the capability of processing large, high frame rate images in real time.

Recent advances in real-time synthetic scene generation for Hardware-in-the-loop (HWIL) testing at the U.S. Army Aviation and Missile Command (AMCOM) Aviation and Missile Research, Development, and Engineering Center (AMRDEC) improve both performance and fidelity. Modeling ground target scenarios requires tradeoffs because of limited texture memory for imagery and limited main memory for elevation data. High- resolution insets have been used in the past to provide better fidelity in specific areas, such as in the neighborhood of a target. Improvements for ground scenarios include smooth transitions for high-resolution insets to reduce high spatial frequency artifacts at the borders of the inset regions and dynamic terrain paging to support large area databases. Transport lag through the scene generation system, including sensor emulation and interface components, has been dealt with in the past through the use of sub-window extraction from oversize scenes. This compensates for spatial effects of transport lag but not temporal effects. A new system has been developed and used successfully to compensate for a flashing coded beacon in the scene. Other techniques have been developed to synchronize the scene generator with the seeker under test (SUT) and to model atmospheric effects, sensor optic and electronics, and angular emissivity attenuation.

Infrared dynamic scene simulation using resistive arrays and projection optics is becoming increasingly common for FLIR's and missile seekers that have narrow to moderate fields of view. This simulation capability enables an imaging system to be tested under a wide variety of simulated scenarios while mitigating some of the cost and complexity of field-testing. OPTICS 1, Inc. has completed a Phase I SBIR and is currently conducting Phase II activities to design, fabricate and test an infrared scene projector for wide-angle infrared imaging systems. Specifically, a need was identified to develop dynamic scene simulation capability for extremely wide-angle infrared imagers such as that under development by OPTICS 1 for contract FO8630-98-C-0022 in support of the Programmable Integrated Ordinance Suite (PIOS) program. This sensor images a full hemispheric field of view in the long-wave infrared (LWIR) waveband and therefore presents extreme challenges for scene projection. A paper under the same title was submitted and presented in 1999 defining the progress reached under the Phase I program. This paper describes progress under the Phase II program which will culminate in hardware delivered to the KHILS facility at Eglin AFB, FL in the fall of 2000. A brief overview of the units to be tested is included in Section 2 and a similar overview of the projector layout and nominal performance is contained in Section 3. The majority of this publication discusses the analyses conducted for the projector assembly and specific issues that were address both from the analyses and in the specification of several components. This information is included in Section 4. The design consists of a scene projection channel and a solar simulation channel. The scene channel is designed to use a resistive array and contains a 2X zoom relay assembly to accept array formats between 1.0 and 2.0 inches. The solar simulation channel uses a tunable laser diode to simulate the sun in the field of view (FOV). This channel utilizes orthogonal mirrors driven by galvanometer motors to simulate apparent movement of the sun in the FOV due to missile body motions. The two channels are combined at a dichroic beamsplitter and utilize the final collimating subassembly together.

Optical Sciences Corporation has designed and implemented a 116 inch exit pupil relief optical system for dynamic infrared scene projection to flight table mounted seekers at the U.S. Army Missile Command (AMCOM) Research, Development, and Engineering Center (RDEC). The optical system collimates the output from a 512 X 512 element resistor array in the 3 - 5 micrometer waveband. The large pupil stand-off is necessary to support projector operation in a millimeter wave (MMW) anechoic chamber. The facility is designed to stimulate a common aperture, dual-band seeker with millimeter wave and IR imagery via a dichroic beam combiner. The dichroic beam combiner is located in the anechoic chamber and reflects the IR scene while transmitting MMW signals. The optical system exhibits distortion of less than 0.5% over the full field of view and chromatic focal shift of less than 10% of the diffraction limited range. The performance of the system is limited by the diffraction limit. This document describes the simulation environment and arrangement, outlines the design procedure from predesign and achromatization to final tolerancing, and presents final test data and sample imagery.

It is shown that commercial-off-the-shelf (COTS) renderers can be used for covering the simultaneous fine temperature resolution and large dynamic range specifications associated with the demands of medium-wave infrared scene projection applications. Appropriate use of the RGB capabilities of the COTS renderer combined with redistribution of the binary scene data by using a nonlinear transformation enables the dual specifications for 0.1 degree Celsius small signal temperature resolution and > 400 degree Celsius range in simulated temperature difference to be simultaneously met.

The one-dimensional nonuniformity scene generation method presented in an earlier paper is extended to the two- dimensional case of real interest. It is shown that the algorithm applied to the one-dimensional case is extendable although its speed of convergence is reduced in two dimensions because of the increased mixing of nonuniformity information. Alternative nonuniformity correction algorithms are developed and compared and it is demonstrated that by utilizing an estimate of the point spread function the scene correction efficiency can be substantially improved.

The 1:1 projector:NUC sensor mapping system reported in 1999 showed that small sub-arrays of projector pixels could be corrected to a fine degree. This system has been developed to join together sub-arrays and complete the NUC operation on a whole resistor array in service. Outline detail is given of the general principle of the correction, the methods involved, covering merging of sub-arrays, strategies for dead pixels and the application of corrections in real time, together with comment on the measurement time and performance against specification.

The KHILS Vacuum Cold Chamber (KVACC) was developed to provide the capability of performing hardware-in-the-loop testing of infrared seekers requiring scenes involving cold backgrounds. Being able to project cold backgrounds enables the projector to simulate high-altitude exoatmospheric engagements. Previous tests with the KVACC projection system have used only one resistive-array projection device. In order to realistically stimulate a 2-color seeker, it is necessary to project in two, independently controlled IR bands. Missile interceptors commonly use two or more colors; thus, a 2-color projection capability has been developed for the KVACC system. The 2- color projection capability is being accomplished by optically combining two Phase 3 WISP arrays with a dichroic beam combiner. Both WISP arrays are cooled to user-selected temperatures ranging from ambient temperature to below 150 K. In order to test the projection system, a special-purpose camera has also been developed. The camera is designed to operate inside the vacuum chamber. It has a cooled, all- reflective broadband optical system to enable the measurement of low radiance levels in the 3 - 12 micrometer spectrum. Camera upgrades later this year will allow measurements in two independent wavebands. Both the camera and the projector will be described in this paper.

Phase 3 WISP arrays and BRITE arrays are currently being used extensively in many projection systems in many different facilities. These arrays have not been annealed at the factory, and previous tests with the arrays have revealed instabilities in the radiometric output when the arrays are driven at higher voltages. In some applications, the instabilities can be avoided by operating the arrays at lower voltages. In many KHILS applications, it is desirable to drive the arrays with the highest possible voltages to simulate hot missile targets. In one KHILS application (the KHILS VAcuum Cold Chamber, KVACC), the arrays are cooled to near cryogenic temperatures and then driven to high voltages. At lower substrate temperatures, the characteristic responses of the emitters change. Thus, it is important that the response and the stability of the radiometric output of the arrays be well understood for various substrate temperatures, and that the arrays either be annealed or operated below the voltage where the emitters begin to anneal. KHILS has investigated annealing procedures in the past, but there was concern that the annealing procedures themselves -- driving the arrays at high voltages for long times -- would damage the arrays. In order to understand the performance of the arrays better, and to reduce risks associated with driving the arrays at high voltages and operating the arrays at low substrate temperatures, a systematic measurement program was initiated. The radiometric output of new Phase 3 WISP arrays was accurately measured as a function of voltage and time. Arrays designated for testing were driven to the higher voltages and the radiometric output was measured for as long as two hours. Curves indicative of the annealing were observed, and it was determined that the maximum stable output without annealing was about 500 K (MWIR apparent temperature). Blocks of emitters were annealed and tested again. It was determined that stable output of as much as 680 K could be obtained with annealed emitters. KHILS personnel worked with Honeywell Technology Center (HTC) to establish annealing procedures that could be done by HTC in the future. Conclusions to date are that once the emitters are sufficiently annealed, their output does not change further with time, except for some small transient effects that will be discussed in the paper.

The Factory Acceptance Test (FAT) results for the projection optical subsystem (POS) of US Army STIRCOM's dynamic infrared scene projector (DIRSP) are presented in this paper. DIRSP is a low background (-35 degrees Celsius) hardware-in-the- loop (HWIL), long-wave infrared (LWIR) scene projector built by Mission Research Corporation (MRC) for use by the Redstone Technical Test Center (RTTC). It has an effective emitter array size of 1632 X 672 suspended-membrane micro-resistor elements. The POS is responsible for generating this effective array size from three smaller arrays using a mosaic image combiner, adding background light from an external blackbody, and collimating the combined radiation with a 5:1 vacuum enclosed -35 degree Celsius zoom lens. The FAT results reported demonstrate good POS performance compared to the design for focal length, F/#, MTF and apparent temperature.

The advent of high resolution infrared resistor arrays, has greatly increased the level of fidelity of infrared sensor testing that can be accomplished in the cost effective laboratory environment. However, the sensor output image quality depends on the uniformity of the projector array. In addition to the advanced proprietary design and fabrication process used to create a highly uniform emitter array. Santa Barbara Infrared, Inc. (SBIR) applies a high speed correction algorithm to the incoming data stream that improves the uniformity of the final infrared image. The key to this algorithm is a set of calibrated tables that are measured for each emitter element in the array. SBIR has developed a Calibration Radiometry System (CRS) which is used to quickly perform these high precision measurements for each emitter element. This paper looks at the CRS system, reviews the algorithms used for applying the correction and for making the calibration measurements. It concludes with some initial results showing the effect of the calibration tables derived using the CRS.

This paper describes the recent addition, characterization, and integration of emerging technologies for dynamic infrared scene projection at the US Army Aviation and Missile Command's (AMCOM) Advanced Simulation Center (ASC). Infrared scene projection performs a vital role in the daily testing of tactical and theatre missile systems within these Hardware-in- the-Loop (HWIL) laboratories. Topics covered within this paper include the addition and characterization of new Honeywell and Santa Barbara infrared emitter arrays, a five-axis flight motion table test configuration, unique calibration/NUC schemes, added software support, verification/validation results, and supplemental projection systems. A new dynamic IR scene projector technology based upon the Digital Micromirror Device^TM is also presented in the paper, as well as example imagery from several of the projector systems.

This paper describes infrared (IR) scene generation and validation activities at the U.S. Army Aviation and Missile Command's (AMCOM) Dual-Mode Hardware-in-the-Loop (HWIL) Simulation. The HWIL simulation validation results are based on comparison of infrared seeker data collected in the HWIL simulation to infrared seeker data collected during captive flight tests (CFTs). Use of CFT data allows a simulation developer to quantify not only the radiometric fidelity of the simulation inputs, but also the effects that any limitations of the inputs may have on simulation validity with respect to a particular seeker and its algorithms. Validation of this type of simulation is a complex process and all aspects of the validation are covered. Topics include real-time IR signature modeling and validation, simulation output verification, projected energy verification, and total end-to-end simulation validation. Also included are descriptions of the different types of CFT scenarios necessary for simulation validation and the comparison methodologies used for each case.

Turntable data collection on ground targets using an instrumentation W-band monopulse radar is reported. The data collection site, instrumentation, and test methodology are described. Preliminary analysis results showing target RCS comparisons are reported. The turntable measurements are used to generate point scatterer target models for all-digital and real-time hardware-in-the-loop (HWIL) simulations. Model development techniques are described. The models are validated against measured data utilizing generic high range resolution acquisition and tracking algorithms.

Signature predictions for full-scale vehicles at Ka-band frequencies can require weeks or months of CPU time for completion; consequently, high performance computers are required in order for prediction codes to be useful in simulation support. Recent advances in Commodity-off-the-Shelf (COTS) personal computer (PC) hardware along with open-source operating systems such as Linux allow for a cost-effective solution to computational requirements routinely encountered in signature analysis and synthetic data generation in support of hardware-in-the-loop (HWIL) simulation. This paper presents the development and evaluation of a Pile-of-PC (PoPC) cluster in support of full-scale, high-frequency signature predictions.

This paper describes a High Fidelity Synthetic IR Imaging Model which attempts to generate accurate static images as would be seen by a defined IR sensor given the target type and the atmospheric conditions. The model attempts to be quite general in its accommodation of physical processes yet maintain radiometric accuracy. Its main application are to assist in the validation of real-time IR scene generation software, and as a tool which can be used for range performance studies of electro-optical systems. The software model allows facet modeling of targets including temperature profiles and material properties. LOWTRAN/MODTRAN is used to provide atmospheric data for transmittance and self-radiation. Optical systems are described in terms of their transmittance and point spread function, both as functions of wavelength, and a self radiation term having temperature and material properties. At each wavelength desired the model generates descriptions of the flux distribution falling on the focal plane of the sensor system. The flux from different sources is added together to form the total flux distribution on the focal plane. Pixels on the focal plane are modeled by groups of facets with associated material properties allowing the shape and wavelength sensitivity to be expressed. The raw pixel output is obtained by integrating the flux distribution over the component facets and across wavelengths. Following non-uniformity modeling a convolution is applied which models readout smearing. Bandlimited noise is then added. The model is also able to generate and apply a matched filter to the output image. The model is designed to use common commercial software tools such as Multigen for target modeling and Open GL for the rendering. The model currently executes on Silicon Graphics hardware.

The Defence Science and Technology Organization (DSTO) of Australia is currently considering the implementation of a commercial-off-the-shelf (COTS) software package called SensorVision^TM to fulfil the scene generation function of an infrared (IR) hardware-in-the-loop (HIL) system. Before the software can be used in the intended application, there is a need to verify and validate the SensorVision models to ensure that the generated scenes are sufficiently realistic for HIL simulation purposes. This paper reports a section of work pertaining to the validation of the temperature prediction models employed by SensorVision. Predicted diurnal temperature profiles of air and a concrete sample are compared against experimental data collected from a location in northern Australia. It is shown that these models generate results that are inaccurate for the location considered. The errors are attributed to the inability of the code to allow users to define atmospheric profiles customized to geo-specific locations. However, reasonable agreement between predicted and measured concrete surface temperatures were obtained empirically by manipulating the heat transfer parameters associated with the concrete sample.

The status of development of resistor-array infra-red scene projector devices at BAE SYSTEMS is that two variants of a 512 X 512 array have each been brought to a second development stage, whilst work on higher complexity arrays is slow but purposeful. In this paper we describe the latest features of the 512 arrays, exhibiting on the one hand high fidelity performance through a ballast-load configuration, and on the other hand very high apparent temperature output, coupled with high speed performance. For higher complexity arrays we describe some of the system philosophy and preliminary design work.

In the past year, Honeywell has developed a 512 X 512 snapshot scene projector containing pixels with very high radiance efficiency. The array can operate in both snapshot and raster mode. The array pixels have near black body characteristics, high radiance outputs, broad band performance, and high speed. IR measurements and performance of these pixels will be described. In addition, a vacuum probe station that makes it possible to select the best die for packaging and delivery based on wafer level radiance screening, has been developed and is in operation. This system, as well as other improvements, will be described. Finally, a review of the status of the present projectors and plans for future arrays is included.

DGA/DCE/LRBA (Laboratoire de Recherches Balistiques et Aerodynamiques), the French MoD missiles and navigation evaluation center has developed several HWIL facilities in order to test the IR-autoguidance-loops of tactical missiles. This IR autoguidance laboratory is composed of several IR image projection systems based on a visible to IR transduction principle. A previous paper has presented the 1999 achievements of LRBA in this field of research. This new paper first describes the latest evolutions achieved by LRBA in this domain, and then details the image projection layouts based on these improvements. It consists in two main facilities: a ground target scene projection layout and a much more complex animated air target scene projection system. This second testbed features the simultaneous use of a low temperature scene projection layout and three high temperature channels designed to modelize the hot parts of an aircraft and its environment. This allows the delivery of continuous images (100% fill factor) for anti-aircraft missile evaluation, at a relatively low cost. The optimization of this facility and especially the channels synchronization and spatial superposition is also discussed. As a conclusion, future HWIL facilities are presented.

Current test and evaluation methods are not adequate for fully assessing the operational performance of imaging infrared sensors while they are installed on the weapon system platform. The use of infrared (IR) scene projection in test and evaluation will augment and redefine test methodologies currently being used to test and evaluate forward looking infrared (FLIR) and imaging IR sensors. The Mobile Infrared Scene Projector (MIRSP) projects accurate, dynamic, and realistic IR imagery into the entrance aperture of the sensor, such that the sensor would perceive and respond to the imagery as it would to the real-world scenario. The MIRSP domain of application includes development, analysis, integration, exploitation, training, and test and evaluation of ground and aviation based imaging IR sensors/subsystems/systems. This applies to FLIR systems, imaging IR missile seekers/guidance sections, as well as non-imaging thermal sensors. The MIRSP Phase I, 'pathfinder' has evolved from other scene projector systems, such as the Flight Motion Simulator Infrared Scene Projector (FIRSP) and the Dynamic Infrared Scene Projector (DIRSP). Both of these projector systems were designed for laboratory test and evaluation use rather than field test and evaluation use. This paper will detail the MIRSP design to include trade-off analysis performed at the system/subsystem levels. The MIRSP Phase II will provide the capability to test and evaluate various electro-optical sensors on weapon platform. The MIRSP Phase I and II will be advancing current IR scene projector technologies by exploring other technologies such as mobility/transportability, packaging, sensors, and scene generation.

Santa Barbara Infrared's (SBIR) MIRAGE (Multispectral InfraRed Animation Generation Equipment) is a state-of-the-art dynamic infrared scene projector system. Imagery from the first MIRAGE system was presented to the scene simulation community during last year's SPIE AeroSense 99 Symposium. Since that time, SBIR has delivered five MIRAGE systems. This paper will provide an overview of the MIRAGE system and discuss the current status of the MIRAGE. Included is an update of system hardware, and the current configuration. Proposed upgrades to this configuration and options will be discussed. Updates on the latest installations, applications and measured data will also be presented.

The IR detector array, which is the heart of any imaging system or missile seeker, continues to evolve toward larger size, smaller pixels, and higher sensitivity. Any scene projector that is intended to test one of these advanced devices must keep pace. As IR scene projection evolves to 1024 X 1024 and 1024 X 2048 arrays, both the emitter array and drive electronics must overcome numerous technological challenges. This paper discusses the approach taken to provide the same 200 Hz frame rate, 16-bit accuracy, and high operability already demonstrated with 512 X 512 MIRAGE arrays in a larger format. In addition to current capabilities that are to be preserved in the design of larger devices, scalability of the architecture to allow growth to even larger formats is desired. Other features such as windowing and even higher frame rates are critical for future applications.

Flight tables are a 'necessary evil' in the Hardware-In-The- Loop (HWIL) simulation. Adding the actual or prototypic flight hardware to the loop, in order to increase the realism of the simulation, forces us to add motion simulation to the process. Flight table motion bases bring unwanted dynamics, non- linearities, transport delays, etc to an already difficult problem sometimes requiring the simulation engineer to compromise the results. We desire that the flight tables be 'dynamically transparent' to the simulation scenario. This paper presents a State Variable Feedback (SVF) control system architecture with feed-forward techniques that improves the flight table's dynamic transparency by significantly reducing the table's low frequency phase lag. We offer some actual results with existing flight tables that demonstrate the improved transparency. These results come from a demonstration conducted on a flight table in the KHILS laboratory at Eglin AFB and during a refurbishment of a flight table for the Boeing Company of St. Charles, Missouri.

This paper describes work performed by the DERA Farnborough UK to provide a laboratory based simulation capability for investigating airborne Infra Red Countermeasure performance against both current reticle threat seekers and future seekers incorporating focal plane array imaging technology. The object of the work was to provide a hardware in the loop facility based around a Five Axis Motion Simulator (FAMS) built by Carco, to allow tests and flyout simulations to be undertaken for performance evaluation. The principal area of research involved the design and construction of a number of source rigs for fitting to the target, or outer, arm of the FAMS to allow both aircraft and countermeasure sources to move realistically in relation to a seeker mounted on the inner FAMS axes. Rigs that have been built include, a multiple point source rig capable of allowing aircraft and multiple countermeasure point sources to move independent of each other, a wide band source rig incorporating a multiple wavelength refractive collimator for investigating spectral countermeasures and two color seeker technology and a rig based on a two port collimator which allows optical mixing of high temperature countermeasure sources.