The Air Force Electronic Warfare Evaluation Simulator IR Countermeasures 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, LASERs, flares and lamp-based jammer systems. The simulations of IR missiles in flight include real missile seeker hardware mounted in a six degree-of-freedom flight simulation table. The simulations of aircraft signatures and IR countermeasures are accomplished by using up to eight xenon arc lamps, located in 9 inch X 3 inch cylindrical housings, in the presentation foreground. A mirror system keeps the high intensity IR sources in the missile field of view. Range closure is simulated in the background by zooming in on the scene and int eh foreground by separating and controlling the irises of the arc lamp sources for property spatial and intensity characteristics. Al relative motion and range closure is controlled by missile flyout software and aircraft flight-profile software models.

The U.S. Army Aviation Technical Test Center (ATTC) provides developmental test support to the Army's aviation community. An increasing dependence on modeling and simulation activities has been required to obtain more data as funding decreases for traditional flight-testing. The Mobile Infrared Scene Projector (MIRSP) system, maintained and operated by ATTC, is being used to gather initial data to measure the progress of developmental Forward Looking IR (FLIR) system activities. The Army continues to upgrade and add new features and algorithms to their FLIR sensors. The history with MIRSP shows that it can benefit the FLIR system development engineers with immediate feedback on algorithm changes. ATTC is also heavily involved with testing pilotage FLIR sensors that typically are less algorithm intensive. The more subjective nature of the pilotage sensor performance specifications requires a unique test approach when using IRSP technologies. This paper will highlight areas where IRSP capabilities have benefited the aviation community to date, describe lessons that ATTC has gained using a mobile system, and outline the areas being planned for upgrades and future support efforts to include pilotage sensors.

The floating point Fast Fourier Transform (FFT) is one of the most useful basic functions available to the image and signal processing engineer allowing many complex and detailed special functions to be implemented more simply in the frequency domain. In the Hardware-in-the-Loop field an image transformed using FFT would allow the designer to think about accurate frequency based simulation of seeker lens effects, motion blur, detector transfer functions and much more. Unfortunately, the transform requires many hundreds of thousands or millions of floating point operations on a single modest sized image making it impractical for realtime Hardware-in-the-Loop systems. .until now. This paper outlines the development, by Nallatech, of an FPGA based IEEE floating point core. It traces the subsequent use of this core to develop a full 256 X 256 FFT and filter process implemented on COTS hardware at frame rates up to 150Hz. This transform can be demonstrated to model optical transfer functions at a far greater accuracy than the current spatial models. Other applications and extensions of this technique will be discussed such as filtering for image tracking algorithms and in the simulation of radar processing in the frequency domain.

With the rapid increase in computational power of the standard personal computer, many tasks that could only be performed by a mini-computer or mainframe can now be performed by the common personal computer. Ten years ago, computational and data transfer requirements for a real-time hardware-in-the-loop simulator could only be met by specialized high performance mini-computers. Today, personal computers shoulder the bulk of the computational load in the U.S. Army Aviation and Missile Command's Radio Frequency Simulation System, and one of the U.S. Army Aviation and Missile Command's millimeter wave simulation systems is currently undergoing a transition to personal computers. This paper discusses how personal computers have been used as the computational backbone for a real-time hardware-in-the-loop simulator, and some of the advantages and disadvantages of a PC based simulation. This paper also provides some general background on what the Radio Frequency Simulation System (RFSS) is and how it works, since the RFSS has successfully implemented a PC based real-time hardware-in-the-loop simulator.

Control system architecture will help eliminate or reduce non-linear behavior of flight table axes motions. This elimination and reduction will help improve dynamic transparency in HWIL simulations. This paper presents the design, analysis and test results of a three-axis hydraulic flight table using acceleration feedback as a part of the axes servo structure. This approach significantly improves the transient motion of the axis under control producing a very high fidelity flight motion table.

Flight motion simulator (FMS) controllers must be tuned to compensate for nonlinear hydraulic plant characteristics and optimize dynamic response within the specified operating bandwidth of each axis. Carco has developed the Matlab-based Carco Tool Kit that adapts the SigLab data acquisition system to perform the specific stimulus and measurement routines required for efficient FMS tuning. Each controller filter is first simulated in Matlab, added to acquired uncompensated-loop data, and optimized using interactive Bode and Nichols charts. The analog filter tuning component values are then extracted from equivalent PSPICE simulations, while the digital filter coefficients are copied directly into the digital controller programming script.

The objective of the HFMS Program Phase II is to finalize the development and produce a '6 DOF High Frequency Motion Simulator' (HFMS). This system is a continuation of a Phase I Conceptual Design study completed in 2000. The introduction of a unique non-cascaded gimbal configuration offers the ability to increase the closed-loop frequency response of this motion simulator to the 1000 Hz region. The motion base is based on a variant of a hexapod configuration. Unique joints are utilized to provide low friction coupling between the platform and actuators. The high modal frequency is achieved by using a beryllium-aluminum alloy for the platform structure and actuator extensions. A multi-variable feedback system, which uses the actuator position and platform inertial accelerations, provides a control system directly related to the airframe coordinate frame. A unique Forward Kinematics filter has been developed to permit a real time solution of the platform variables by a measurement of the leg extensions. The system provides control of the three angular rotations and three linear displacements, each control loop exhibiting a 1000 Hz bandwidth.

In this paper, LIDAR imaging sensors, 3D synthetic and natural object-centric environment, and temporal ATR are discussed in the context of Modeling and Simulation and Hardware-in-the-loop testing.

We present a design for an IR scene projector for live-fire training applications, based on modification of a commercial-off-the-air laser-light-scene scanner retrofitted with a CO₂ laser and associated IR optics. Design goals include a reusable or at least very inexpensive shoot- through projection screen. This application calls for a wide projection field as compared to typical IR scene-projection systems intended for hardware in the loop testing.

SBIR's MIRAGE Infrared scene projector continues to break new ground in the area of dynamic IR scene projection. In July 2001, SBIR reached an exclusive licensing agreement with Honeywell Research Laboratories to fabricate emitter arrays using their industry standard process. SBIR has moved out aggressively to bring the benefits of this process coupled with the MIRAGE CMOS to the IR projection community. This paper discusses emitter array performance from Honeywell devices fabricated on legacy MIRAGE CMOS. It also discusses SBIR's upgraded CMOS plans, which will take advantage of the Honeywell process to extend the state-of-the-art of IR scene projector performance.

Santa Barbara Infrared (SBIR) is producing a high performance 1,024 x 1,024 Large Format Resistive emitter Array (LFRA) for use in the next generation of IR Scene Projectors (IRSPs). LFRA requirements were developed through close cooperation with the Tri-Service IR Scene Projector working group, and through detailed trade studies sponsored by the OSD Central T&E Investment Program (CTEIP) and a Phase I US Navy Small Business Innovative Research (SBIR) contract. The CMOS Read-In Integrated Circuit (RIIC) is being designed by SBIR and Indigo Systems under a Small Business Innovative Research (SBIR) contract. Performance and features include 750 K MWIR maximum apparent temperature, 5 ms radiance rise time, 200 Hz full frame update, and 400 Hz window mode operation. Ten 8-inch CMOS wafers will be fabricated and characterized in mid-2002, followed by emitter fabrication in late 2002. This paper discusses array performance, requirements flow-down, array design, fabrication of 2 X 2-inch CMOS devices, and plans for subsequent RIIC wafer test and emitter pixel fabrication.

The search for optimal IR scene projection nonuniformity correction procedures reported in earlier papers is continued. In this paper the application of the flood nonuniformity correction procedure described earlier is extended to the case where only a sublattice of projector pixels is lit, enabling nonuniformity correction for the practically interesting case of greater-than-unity mapping ratios.

An alternative class of infrared projector real-time nonuniformity correction processor is introduced, based on the concept that the fundamental role of the processor is to reverse each of the projector processing steps as the input DAC voltage word is converted into infrared signal radiance output. The design is developed by assessment of the sequence of processes occurring within the projector and is tested by simulation. It is shown that there is potential for high fidelity nonuniformity correction across the infrared dynamic range without the need for the introduction of curve-fitting breakpoints.

The Aviation and Missile Research, Engineering, and Development Center (AMRDEC) of the US Army Aviation and Missile Command (AMCOM) has an extensive history of applying all types of modeling and simulation to weapon system development and has been a particularly strong advocate of hardware-in-the-loop (HWIL) simulation and test for many years. Key to the successful application of HWIL testing at AMCOM has been the use of state-of-the-art IR Scene Projector technologies. This paper describes recent advancements within the AMRDEC Advanced Simulation Center HWIL facilities with a specific emphasis on the sate of the various IRSP technologies employed. Included in these IRSP technologies are the latest Honeywell and Santa Barbara IR emitter arrays, the DMD-based IR projectors, and the laser diode array projector.

The Honeywell resistor arrays produce radiance outputs, which are observed to have a strong non-linear dependence on the voltage out of the digital-to-analog-converters (DACs). In order for the projection system to run in a radiometrically calibrated mode, the radiances in the image generator must be transformed with exactly the inverse of the resistor array response function before they are sent to the DACs. Representing the image values out of the image generator and the values into the DACs with quantized, digital values introduces errors in the radiance out of the resistor array. Given the functional form of the emitter array response and the number of bits used to represent the image values, these errors in the radiometric output due to the quantization effects can be calculated. This paper describes the calculations and presents results for WISP, MSSP, and the new extended range and standard range BRITE II arrays.

This paper describes a simulation and analysis of a sensor viewing a 'pixelized' scene projector like the KHILS' Wideband Infrared Scene Projector (WISP). The main objective of this effort is to understand and quantify the effects of different scene projector configurations on the performance of several sensor signal processing algorithms. We present simulation results that quantify the performance of two signal processing algorithms used to estimate the sub-pixel position and irradiance of a point source. The algorithms are characterized for different signal-to-noise ratios, different projector configurations, and two different methods for preparing images that drive the projector. We describe the simulation in detail, numerous results obtained by processing simulated images, algorithms and projector properties, and present conclusions.

As discussed in a previous paper to this forum, optical components such as collimators that are part of many infrared projection systems can lead to significant distortions in the sensed position of projected objects versus their true position. The previous paper discussed the removal of these distortions in a single waveband through a polynomial correction process. This correction was applied during post-processing of the data from the infrared camera-under-test. This paper extends the correction technique to two-color infrared projection. The extension of the technique allows the distortions in the individual bands to be corrected, as well as providing for alignment of the two color channels at the aperture of the camera-under-test. The co-alignment of the two color channels is obtained through the application of the distortion removal function to the object position data prior to object projection.

A new hardware-in-the-loop modeling technique was developed at the US Naval Research Laboratory (NRL) for the evaluation of IR countermeasures against advanced IR imaging anti-ship cruise missiles. The research efforts involved the creation of tools to generate accurate IR imagery and synthesize video to inject in to real-world threat simulators. A validation study was conducted to verify the accuracy and limitations of the techniques that were developed.

DGA/DCE/LRBA, the French MoD missiles and navigation evaluation center has developed several HWIL facilities in order to test the IR-autoguidance-loops of tactical missiles. LRBA has initiated the acquisition of SPECTRAL, a dedicated hardware and software configuration. SPECTRAL (Multipurpose System for Laboratory Evaluation of Image Processing Calculators) is a complete system including hardware and software designed for the evaluation of different missile functions or equipment (on-board image processing software, image processing calculators, imagers, terminal guidance and control performances). The main feature of this system is its capability to generate images representative of those elaborated by an infrared missile seeker, in real time. SPECTRAL is designed with an architecture for a multi-user environment including workstations carrying out several operations. Acceptance Test Procedures of SPECTRAL are being discussed and the first results are presented here. As a conclusion, we provide a comparison with existing image generating systems at LRBA's facilities.

Amherst Systems has previously developed a Real-time IR/EO Scene Simulator (RISS) for use in reactive, hardware-in-the-loop testing of infrared sensor systems. This paper will report on how RISS is currently being used to test and develop a variety of sensor systems, with emphasis on the use of both measured and modeled signature data to create test scenarios. Ongoing efforts to utilize models and data such as DIRSIG, RadTherm, MuSES, TERTEM, and PRA WITMaps will be examined, and their relevance to specific testing requirements will be explored. For example, Amherst Systems has recently completed an effort for a U.S. Government organization to construct a suite of operational scenarios to be used in conjunction with its previously installed RISS in order to stimulate a specific IR/EO sensor in a test environment. These scenarios used both measured and modeled data. This paper will explain how data from several sources were assembled into cohesive scenarios to model real, operational environments and engagements. It will detail the sources for all measured data that were used throughout the scenario development process. It will also explain how readily available, government-furnished models (such as MODTRAN, DISAMS, SPF/SPURC, and BLUEMAX) were used to construct these integrated scenarios, making validation of the scenarios much more feasible.

Future types of direct detection LADAR seekers will employ focal plane arrays in their receivers. Existing LADAR scene projection technology cannot meet the needs of testing these types of seekers in a Hardware-in-the-Loop environment. It is desired that the simulated LADAR return signals generated by the projection hardware be representative of the complex targets and background of a real LADAR image. A LADAR scene projector has been developed that is capable of meeting these demanding test needs. It can project scenes of simulated 2D LADAR return signals without scanning. In addition, each pixel in the projection can be represented by a 'complex' optical waveform, which can be delivered with sub-nanosecond precision. Finally, the modular nature of the projector allows it to be configured to operate at different wavelengths. This paper describes the LADAR Scene Projector and its full capabilities.