The Fast Line-of-sight Imagery for Target and Exhaust Signatures (FLITES) is a High Performance Computing (HPC-CHSSI) and Missile Defense Agency (MDA) funded effort that provides a scalable program to compute highly resolved temporal, spatial, and spectral hardbody and plume optical signatures. Distributed processing capabilities are included to allow complex, high fidelity, solutions to be generated quickly generated. The distributed processing logic includes automated load balancing algorithms to facilitate scalability using large numbers of processors. To enhance exhaust plume optical signature capabilities, FLITES employs two different radiance transport algorithms. The first algorithm is the traditional Curtis-Godson bandmodel approach and is provided to support comparisons to historical results and high-frame rate production requirements. The second algorithm is the Quasi Bandmodel Line-by-line (QBL) approach, which uses randomly placed "cloned" spectral lines to yield highly resolved radiation spectra for increased accuracy while maintaining tractable runtimes. This capability will provide a significant advancement over the traditional SPURC/SIRRM radiance transport methodology.

This paper describes the use of an image query database (IQ-DB) tool as a means of implementing a validation strategy for synthetic long-wave infrared images of sea clutter. Specifically it was required to determine the validity of the synthetic imagery for use in developing and testing automatic target detection algorithms. The strategy adopted for exploiting synthetic imagery is outlined and the key issues of validation and acceptance are discussed in detail. A wide range of image metrics has been developed to achieve pre-defined validation criteria. A number of these metrics, which include post processing algorithms, are presented. Furthermore, the IQ-DB provides a robust mechanism for configuration management and control of the large volume of data used. The implementation of the IQ-DB is reviewed in terms of its cardinal point specification and its central role in synthetic imagery validation and EOSS progressive acceptance.

The German MoD Research Establishment for Electronics and Communication Technology is currently implementing one of the world's largest advanced dome based Hardware-in-the-Loop simulation facility with high dynamics multispectral target representation. e.sigma Systems, Munich, is the prime contractor for the simulation systems and associated infrastructure. The facility will be used for research, development and validation of fire control and optronic seeker systems. The visual system for the target simulation contains a 40m dome with a special screen surface of 2200 sqm and a number of high resolution projection systems for the visual and IR spectrum. The simulation system also includes high dynamics, high precision motion simulators for the multispectral target projectors and the seeker systems under test. A high speed computer network for control, data acquisition and data recording links the subsystems at real time simulation rates of 1000Hz. The paper discusses the purpose of the simulation facility and its implementation.

The effectiveness of a HWIL facility for developing missile guidance and targeting systems is limited by the quality of the elements that simulate the continuous physical processes. A motion simulator, which stimulates the inertial measurement and targeting sensors, must produce motion that is consistent with the actual physical processes. The effectiveness of a HWIL simulation is progressively degraded by each non-ideal element or process in the loop. The interface between the simulation computer and the motion system is traditionally a problematic link that is resolved once and for all in the Acutrol3000 Motion Control instrumentation. This paper focuses on issues relating to data synchronization, time skew correction, multi-rate data smoothing, and reduced state motion vectors. Concepts are addressed and results are presented.

This paper discusses the major discriminators and parameters in the selection of a type of motion simulator. Boundary curves are presented for each type of system to allow an initial selection of a motion simulator. A discussion of the advances of magnetic materials, hydraulic pressures, and sealing techniques are presented to show future trends in both types of simulators.

EADS/LFK-Lenkflugkoerpersysteme GmbH develops missile systems for a wide field of military applications. The Hardware-in-the-Loop (HWIL) facility of LFK in Unterschleissheim uses a five axis motion simulation table, an IR scene projection system and powerful simulation computers. The system is designed for test and evaluation of different missile programs fitting the dimensions of the five axis table and it's dynamic performance. Development, configuration management and maintenance of HWIL applications are time and cost consuming processes. Current missile programs are very complex and the development of modern missile systems has to be completed within short time intervals. Programming of HWIL as a test bench is getting a very complex and a high sophisticated task, which runs usually parallel to the missile development process. Programming of HWIL applications, despite physical missile models, means in the most cases low level programming of control loops, state machines, communication tasks, device drivers and integration of physical models. Hard requirements on the faultless functionality and on the accurate real-time behavior make the development and the test of HWIL software an ambitious and complex software development project. So new generation software development methods dealing with complex systems for HWIL applications are needed to shorten the development time, to lower the costs, to simplify the test and to reach a faultless functionality.

A broadband, low-distortion, 2:1 zoom collimator has been designed for projection of infrared scenes in the spectral region of 3.0 to 12.0 micrometers. This collimator provides dynamic scenes for the Kinetic Kill Vehicle Hardware-in-the Loop Simulation (KHILS) facility for testing of missile seekers and other FLIRs. This system, the Target Simulator Optical System (TSOS) is similar to the WISP Optical System already installed at KHILS by Brashear LP, but is lightweighted to allow mounting onto the outside axis of a Flight Motion Simulator. This paper explains the general requirements of the projection collimator optics and describes the system design, assembly and test. The collimator projects dynamic scenes generated by two 1024 x 1024 or 512 x 512 arrays of resistive-emitter elements. The system is composed of four off-axis, powered mirrors, a beamcombiner, spectral filters and array windows. Three of the mirrors are moveable to accommodate changing the field-of-view. Distortion is less than 1.0% at any field position.

A continual effort to develop the latest scene simulation technologies into actual space simulation test chambers is necessary to ensure that the U.S. has the proper ground test capabilities to test space defense systems. This involves the integration of high-fidelity, complex, and dynamic scene projection systems, including multiple-band source subsystems and the spectral tailoring methods used to simulate the desired target temperatures. Comprehensive analysis and measurement of the properties of the optical components involved are also required. This paper discusses implementation of these techniques in the space sensor test facilities of the Arnold Engineering Development Center (AEDC).

This paper will present the results and progress of AMRDEC'S development of two cold background, flight motion simulator (FMS) mountable, emitter array based infared scene projectors for use in hardware-in-the-loop systems simulation. The goal for this development is the ability to simulate realistic low temperature backgrounds for windowed/domed seekers operating in tactical and exo-atmospheric simulations. Two projectors have been simultaneously developed; the first represents a streamlined pathfinder version consisting of a Honeywell emitter array and refractive optical system contained within an FMS-mountable environmental chamber cooled to -55 degrees Celsius. The second system is the full-capability version including a cryogenically operated BRITE II emitter array, zoom optics, integrated steerable point source and high-frequency jitter mirror contained within a similar FMS-mountable environmental chamber. This system provides a full-FOV cold background, two dimensional dynamic IR scene projection, a high dynamic range independently steerable point source and combined optical path high frequency jitter control. Both projectors are designed to be compatible with operation on a 5 axis electric motor driven Carco flight motion simulator. Results presented will include design specifications, optical performance, samlple imagery, apparent temperature and proposed future improvements.

The KHILS Vacuum Cold Chamber (KVACC) has formed the basis for a comprehensive test capability for newly developed dual-band infrared sensors. Since initial delivery in 1995, the KVACC chamber and its support systems have undergone a number of upgrades, maturing into a valuable test asset and technology demonstrator for missile defense systems. Many leading edge test technologies have been consolidated during the past several years, demonstrating the level of fidelity achievable in tomorrow's missile test facilities. These technologies include resistive array scene projectors, sub-pixel non-linear spatial calibration and coupled two-dimensional radiometric calibration techniques, re-configurable FPGA based calibration electronics, dual-band beam-combination and collimation optics, a closed-cycle multi-chamber cryo-vacuum environment, personal computer (PC) based scene generation systems and a surrounding class-1000 clean room environment. The purpose of this paper is to describe this unique combination of technologies and the capability it represents to the hardware-in-the-loop community.

In this report, we show both theoretically and experimentally how the IR signature of a semiconductor scene (with band gap energy Eg) can be monitored through contactless emissivity control even if this scene thermometric temperature is kept constant. More specifically, we show how a scene emissivity in the spectral band beyond the fundamental absorption range (ω2 < Eg / h, 3 to 5 μm and 8 to 12 μm transparency windows) can be dynamically (frame frequency > 20 kHz) monitored by a shorter wavelength photo excitation of non-equilibrium charge carriers (ω1 > Eg/h, "visible range"). Experimental tests performed on Si and Ge scenes (300 < T < 600 K), demonstrate optically generated cold and hot images and, what is more important, negligible temperature contrast between an object and a background (Stealth effect in IR).

The next generation of resistively heated emitter pixels will be required to attain MWIR apparent temperatures on the order of 2000K, which will require pixel temperatures on the order of 3000K. Numerical simulations have been carried out to determine the material properties required to support the desired performance. Research has been performed to identify a set of potential materials for fabricating these devices based on materials science, existing thermophysical properties, thermodynamic stability and compatibility with thin film processing.

The U.S. Army's Research, Development, and Engineering Command's (RDECOM) Aviation and Missile Research, Development, and Engineering Center (AMRDEC) provides Hardware-in-the-Loop (HWIL) test support to numerous tactical and theatre missile programs. Critical to the successful execution of these tests is the state-of-the-art technologies employed in the visible and infrared scene projector systems. This paper describes the results of characterizations tests performed on new mid-wave infrared (MWIR) quantum well laser diodes recently provided to AMRDEC by the Naval Research Labs and Sarnoff Industries. These lasers provide a +10X imrovement in MWIR output over the previous technology of lead-salt laser diodes. Performance data on output power, linearity, and solid-angle coverage are presented. A discussion of the laser packages is also provided.

Hardware-in-the-Loop (HWIL) testing of seeker systems usually requires a 5-axis flight motion simulator (FMS) coupled to expensive hardware for infrared (IR) scene generation and projection. Similar tests can be conducted by using a 3-axis flight motion simulator, bypassing the seeker optics and injecting a synthetically calculated detector signal directly into the seeker. The constantly increasing speed and memory bandwidth of high-end personal computers make them attractive software rendering platforms. A software OpenGL pipeline provides flexibility in terms of access to the rendered output, colour channel dynamic range and lighting equations. This paper describes how a system was constructed using personal computer hardware to perform closed tracking loop HWIL testing of a single detector frequency modulated reticle seeker. The main parts of the system that are described include: * The software-only implementation of OpenGL used to render the IR image with floating point accuracy directly to system memory. * The software used to inject the detector signal and extract the seeker look position. * The architecture used to control the flight motion simulator.

Standard OpenGL-based rendering has sampling limitations. By default these rendering systems point sample rendered pixels. For highly resolved objects, this sampling is adequate to represent the object accurately, but when the object has a relatively small projected area that is on the order of a few pixels, the object intensity is corrupted with aliasing. Hardware anti-aliasing such as multisampling provides minimal relief by offering 4, 8, or 16 samples within a single pixel. However, for hardware-in-the-loop (HITL) scene generation where accurate energy conservation of unresolved sub-pixel objects must be maintained, standard hardware anti-aliasing is not good enough. Zoom anti-aliasing (ZAA) has been proven as a viable solution for rendering objects that would otherwise be grossly under-sampled. Techniques in the past have focused on processing the zoom window pixels in the CPU because the graphics processor unit (GPU) was not general purpose enough to support the zoom window processing. However, this is no longer the case because of the new capabilities of modern graphics processors. This paper presents a modern GPU-based zoom window approach and compares the results to a classic CPU-based approach.

Santa Barbara Infrared's (SBIR) family of MIRAGE infrared scene projection systems is undergoing significant growth and expansion. The first lot of production IR emitters is in fabrication at Microelectronics Center of North Carolina/Research and Development Institute (MCNC-RDI), the state-of-the-art MEMS foundry and R&D center which completed prototype fabrication in early 2003. The latest emitter arrays are being produced in support of programs such as Large Format Resistive Array (LFRA) and MIRAGE 1.5, MIRAGE II, and OASIS. The goal of these new development programs is to increase maximum scene temperature, decrease radiance rise time, support cryogenic operation, and improve operability and yield. After having completed an extremely successful prototype run in 2003, SBIR and MCNC-RDI have implemented a variety of emitter process improvements aimed at maximizing performance and process yield. SBIR has also completed development and integration of the next-generation MIRAGE command and control electronics (C&CE), an upgraded calibration radiometry system (CRS), and has developed test equipment and facilities for use in MIRAGE device wafer probing, test, evaluation, diagnostic, and assembly processes. We present the latest emitter performance data, an overview of emitter foundry processing and packaging improvements, and an update on MIRAGE II, LFRA, and OASIS development programs.

The Multi-Spectral Stimulator described in this paper has been designed to answer the future testing and evaluation needs for emerging multi-spectral technology. This system is portable, low cost, and scalable, and can produce synchronous IR and RF images and signals, respectively, for both injection and projection to multi-mode sensors. The scenes generated are temporally and spatially registered and generated from a three-dimensional database. Its present development provides closed-loop capabilities to a missile simulation. Two adaptive technologies are merged into a flexible system that can stimulate multiple sensors simultaneously in real time. It merges Scientific Research Corporation's Adaptable Radar Environment Simulator (ARES) and Quantum3D/CG2 Inc.'s real-time, multi-spectral Scene Generation system. The stimulator can run in either real-time or stepped mode, providing signals on demand. The resulting stimulator test bed is integrated to a non-real-time high fidelity missile simulation that consists of an IR seeker, IR imaging tracker, and a 6-DOF/Autopilot model. The stimulator design can be modified to stimulate multiple passive sensors, active laser systems, multi-mode systems, multiple radar systems, or almost any combination of sensors. The next planned development stage integrates the system to real-time closed-loop system and associated interface electronics. This will provide a bridge to full hardware-in-the-loop (HWIL) integration for the simulation of a dual mode missile system.

We compare modulation-transfer-function (MTF) measurements for both mid-wave (MWIR) and long-wave IR (LWIR) bands for an IR-laser scene projector based on the digital micro-mirror device (DMD). We evaluate MTF for both IR-CO2 (10.6 micron) and IR-HeNe (3.39 micron) laser systems. This gives a quantitative image-quality criterion for verifying system performance using identical configurations of the DMD, lens, and screen. Different angles of illumination for the MWIR and LWIR were used, to give an output beam always perpendicular to the DMD. For this experiment a set of bar-target images was used to measure the residual modulation depth at the fundamental spatial frequency of the bars. As expected, the MWIR projector system has better MTF than the LWIR system because of diffraction effects occurring at the 17-micron pixels of the DMD.

Hardware-in-the-loop (HWIL) testing has been an integral part of the modeling and simulation efforts at the U.S. Army Aviation and Missile Research, Engineering, and Development Center (AMRDEC). AMRDEC's history includes the development and implementation of several unique technologies for producing synthetic environments in the visible, infrared, MMW and RF regions. With the emerging sensor/electronics technology, LADAR sensors are becoming more viable option as an integral part of weapon systems, and AMRDEC has been expending efforts to develop the capabilities for testing LADAR sensors in a HWIL environment. There are several areas of challenges in LADAR HWIL testing, since the simulation requirements for the electronics and computation are stressing combinations of the passive image and active sensor HWIL testing. There have been several key areas where advancements have been made to address the challenges in developing a synthetic environment for the LADAR sensor testing. In this paper, we will present the latest results from the LADAR projector development and test efforts at AMRDEC's Advanced Simulation Center (ASC).

The new generation PC-based array control electronics (PACE) system for emissive infrared projector real-time scene data processing has opened the potential for the development of more complex real-time nonuniformity correction (RNUC) algorithms than were formerly possible. In this paper, emitter array response data are analyzed in order to identify the underlying physical processes and to identify the form of the RNUC algorithm they suggest. It is shown that although the PACE system is capable of processing the algorithm, the development of a practical RNUC processor would seem to be limited by the complexities that underlie the observed variability in emitter response.

Array nonuniformity is the dominant factor limiting the temperature resolution of the current generation of emissive dynamic infrared scene projectors. Over the past five years or so numerous papers have been presented associated with the measurement of the array nonuniformities and the design and implementation of efficient nonuniformity correction (NUC) techniques. A considerable amount of progress has been made towards achieving the desired NUC goals. A number of factors, however, limit the achievement of fine temperature resolution within emissive infrared projection systems, improvements still being needed to achieve residual nonuniformity levels low enough to satisfy the demanding requirements of low NETD thermal imaging systems. In particular, the NUC camera has a strong influence on the effectiveness of the projector NUC procedure. In this paper we describe an alternative method for collecting projector NUC data that relies on the use of several integration times and also multiple calibration points for correcting the camera nonuniformities, the method being designed to improve the accuracy of the projector NUC procedure.

Spatial distortion effects in infrared scene projectors, and methods to correct them, have been studied and reported in several recent papers. Such effects may be important when high angular fidelity is required of a projection test. The modeling and processing methods previously studied, though effective, have not been well suited for real-time implementation. However, the “spatial calibration” must be achieved in real-time for certain testing requirements. In this paper we describe recent efforts to formalize and implement real-time spatial calibration in a scene projector test. We describe the effect of the scene generation software, “distortion compensation”, the projector, the sensor, and sensor processing algorithms on the transfer of spatial quantities through the projection system. These effects establish requirements for spatial calibration. The paper describes the hardware and software recently developed at KHILS to achieve real-time spatial calibration of a projection system. The technique extends previous efforts in its consideration of implementation requirements, and also in its explicit treatment of the spatial effects introduced by each of the distinct components of the overall system, as mentioned above.

One proven technique for nonuniformity correction (NUC) of a resistor array infrared scene projector requires careful measurement of the output-versus-input response for every emitter in a large array. In previous papers, we have discussed methods and results for accomplishing the projector NUC. Two difficulties that may limit the NUC results are residual nonuniformity in the calibration sensor, and nonlinearity in the calibration sensor's response to scene radiance. These effects introduce errors in the measurement of the projector elements' output, which lead to residual nonuniformity. In this paper we describe a recent effort to mitigate both of these problems using a procedure that combines sensor nonuniformity correction and sensor calibration, detector by detector, so that these problems do not contaminate the projector NUC. By measuring a set of blackbody flood-field images at a dozen or so different temperatures, the individual detector output-versus-input radiance responses can be measured. Similar to the projector NUC, we use a curve-fitting routine to model the response of each detector. Using this set of response curves, a post-processing algorithm is used to correct and calibrate the images measured by the sensor. We have used this approach to reduce several sensor error sources by a factor of 10 to 100. The resulting processing is used to correct and calibrate all of the sensor images used to perform the projector NUC, as one step in the projector NUC. The procedure appears to be useful for any application where sensor nonuniformity or response nonlinearities are significant.

The Air Force Electronic Warfare Evaluation Simulator (AFEWES) Infrared Countermeasures (IRCM) test facility currently has the ability to simulate a complete IRCM test environment, including IR missiles in flight, aircraft in flight, and various IR countermeasures including maneuvers, point-source flares and lamp- and LASER-based jammer systems. The simulations of IR missiles in flight include missile seeker hardware mounted on a six degree-of-freedom flight simulation table. This paper will focus on recent developments and upgrades to the AFEWES IR capability. In particular, current developments in IR scene generation/projection and efforts to optically combining the IR image produced by a resistive array with existing foreground lamp sources.

We at Army Research Laboratory (ARL) have developed 2xD light emitting device (LED) arrays for possible application in infrared (IR) scene projection experiments. These LEDs emit light in the 3-4 μm wavelength region with peak at 3.75 μm when operate at room temperature. The epitaxial structure for LED was grown on GaSb substrate by molecular beam epitaxial (MBE) technology. Mesa sizes ranging from 30-100 μm diameters were used in the device fabrication. By comparing with radiation from blackbody source, we found that the brightness temperature of the infrared LED is in the range of 300-600 K. We obtained very good uniformity in device current and voltage (I-V) characteristics. This paper discusses the LED array design, fabrication and evaluation results.