A standard electro-optical sensor can perform several different surveillance missions to support tactical military users. The missions include environmental sensing, land and ocean remote sensing, tactical missile tracking, and space object surveillance. The key is that while the spacecraft is a standard configuration for all missions, its design is a compromise between the specific requirements for each mission; the orbit chosen and operations mode for each mission also vary. Although sub-optimal for any given mission, standard sensor systems have the advantage of achieving a higher benefit-to-cost ratio by realizing economies of scale in production and reduced development. Point designs of three different multi-mission sensors are presented, supported by design analysis, and encompassing several approaches to telescope design, focal plane design, scanning system design, data processing system design, and orbits/coverage and operations. The resulting sensor system designs are highly capable, compared to existing systems, meet the performance goals established, and yet fit within the tactical satellite class.

Since July 1985, the Foreign Technology Division of the Air Force Systems Command has been sponsoring collections against missiles and space launches from the Western Test Range. The effort is called the Field Observations and Measurements Experiment, or Project FOME. The collections have been done by the Sverdrup Corporation operations located at the Arnold Engineering Development Center (AEDC) in Tennessee. FOME is a ground based program designed for efficient collection of data on plume radiation during flight. Radiometric and spectrometric collections are made from the JR to the UV, the UV measurements being taken during night launches only. One of the advantages of this effort is that it utilizes many of the same instruments used in the AEDC test cells. This helps reduce differences between what is seen in the test cells and what is collected in the field. It also allows the use of off-the-shelf products, as we have not yet seen a need for special "field hardened" instrumentation. The data are used for algorithm development.

The first and the most important step on the way to the absolute high accuracy pointing in balloon-borne remote sensing is a good azimuth stabilization. For this goal it is absolutely necessary to control the non linear friction of the suspension bearings in order to isolate the instrumentation, as much as possible, from the random rotation of the cruise balloon. The paper describes a program simulation of a servo-system that is theoretically capable of 2.6 arc mm of accuracy with a magnetometer sensor in the feedback path only. This pointing accuracy strongly depends on the signal to noise ratio of the sensor employed, but it is possible to approach the theoretical value by means of a particular mechanical arrangement, powered by a torque motor. This active mechanical arrangement (named Pivot and strategically placed at the interconnecting point balloon-payload) houses the necessary suspension bearings. The leakage torque, transmitted from the balloon to the gondola through the load stress of this interconnecting point, is controlled and attenuated simply by putting the bearings of the Pivot in rotation. The parameters of this Pivot and the features of two DC torque motors are the starting points of our simulation design. The second motor, according to the inertia moment of a reaction wheel, provides the torque necessary for any platform motion around the vertical axis. However some mechanical non-linearities, localized exactly at the Pivot level, impose a time domain design either for any settling time control whenever the gondola experiences a new change in azimuth coordinate or during the tracking action of an astrophysical target. The program simulation in the time domain, that is the first step towards a full digital pointing design, has the same utility, for the servo-system analysis, of the unity step response in the Laplace transform field.

A technique based on IR Thermography measurements is proposed to estimate realistic values of electric hardware failure rates corresponding to secondary failures, that is, those caused by past or present out-of-tolerance or abnormal operating conditions. The technique allows the establishment of useful correlations between these failure rates, and the corresponding relevant thermal patterns as mapped using JR Thermography. The technique is applied to practical cases of secondary failures in typical AC and DC electric power network components having to do with failure modes due to abnormal stress, corrosion, and erosion. The application of this technique to fault and failure diagnosis, and both Reliability, Availability, and Maintainability (RAM) Analysis and Probabilistic Risk Assessment (PRA) of electric power networks is also briefly discussed.

GaAs/Al(0.31)Ga(0.69)As IR detector of multiquantum well structure with a single bound state in a GaAs well have been fabricated. The peak wavelength of spectral responsivity at 77 K was 8.3 microns. The measured responsivities were 20 V/W for A-type detectors, 65 V/W for B-type detectors, and 130 V/W for C-type detectors. The corresponding specific detectivities at peak wavelength were 2.8 x 10 exp 9 cm sq rt Hz/W, 2.7 x 10 exp 9 cm sq rt Hz/W, and 2.7 x 10 exp 9 cm sq rt Hz/W, respectively. These values are about one order lower than those of conventional CdHgTe photoconductive devices.

A technique for longwave infrared (LWIR) synthetic image generation is shown which yields improved radiometric accuracy in the 8-14 micron bandpass. This process uses a modified LOWTRAN 6 atmospheric transmission/upwelled radiance code and computer graphics ray-tracing techniques. A scene is created by placing faceted objects into world coordinates with rotation, translation, and scaling parameters. Each facet is assigned a material index and temperature. The material index points to optical properties for that material. The modified LOWTRAN 6 code incorporates sensor response function when computing tables of the atmospheric transmission and upwelled and downwelled radiances. A ray-traced image is then generated. A final synthetic LWIR scene is generated to geometrically match an actual acquired scene so that radiometric comparisons can be made.

A compact focal plane assembly which consists of a linear array of 128 InSb photodiodes and two Si-MOSFET multiplexer IC chips has been developed. The design and fabrication of the photodiode array, the readout circuit on the focal plane, the hybrid packaging, and the operation of the focal plane assembly are described. A small InSb pixel size of 60 microns is used, and the total length of the array is 7.60 mm. A measured radiometric resolution of 0.04 K NE Delta T is obtained for a 300 K target with a simple circuit configuration under the TV-compatible operation.

In this paper a statistical analysis of thermal images, obtained by the line scanning technique, with the view of reducing the image data redundancy is given. The analyzed thermal images are produced by the infrared line scanner on board and by a computer simulation. The statistical analysis is based on grey level mean values, standard deviations and correlations. A special filtering method is proposed to eliminate the line-like interference which appears on enlarged thermal image photographs made from the film.

Deterministic images in the shapes of cos-like variation of average terrain temperature are computer generated with superimposed noise fluctuations due to the terrain and SPRITE detector. The thermal infrared images in this model are generated pixel by pixel. The images are made for periodic cos-like structures along the x-axis, y-axis and isolated hot plates on the flat terrain. The effects of line scanning on noiseless and noisy images are analyzed.

Analytical and experimental research has been conducted to assess the feasibility of detecting and diagnosing deep cracks in concrete dams by means of IR Thermography measurements. A simplified scale-down model of the nonoverflow section in a conventional concrete gravity dam and its reservoir has been designed with the capability of simulating both air-filled and water-filled deep cracks. A high-resolution CMT thermal imager (BSI 7000 equipment) has been utilized for mapping the temperatures at the downstream face of the latter model, under realistic quasi-static thermal conditions, in similar situations both with and without deep cracks present in the concrete body. The results obtained from these measurements compare reasonably well with calculations based on an ad hoc one-dimensional heat-transfer model of the simulated dam-reservoir complex. Appropriate thermal correlations have been found that appear to indicate the feasibility of detecting and diagnosing both air-filled and water-filled deep cracks in concrete dams using IR Thermography. The operating requirements imposed on the IR Thermography equipment to be used, and the reliability of the above detection and diagnosis process have been explicitly addressed.

We have conducted experiments to prove feasibility of a boresighting method between a laser and a Forward Looking Infra- Red (FLIR) system, which has the advantage of working with or without synchronization between the laser pulses and the FLIR scanning. The method is based on the Thermal Target concept (TT); the laser energy is focused on a special substrate which is locally heated and produces a point image on the FLIR screen with respect to the FLIR line of sight which is boresighted. Resistance to laser damage by the required pulse energy densities was established by target lifetime measurements. The TT method can be also used for real time boresighting of the laser with the FLIR, which means that the boresighting is done while looking at the scenery.

A laser heterodyne spectrometer in the 10 micron range is described which enables spectra to be recorded with high resolution and to obtain the true shape of the IR absorption lines. The adjustable temperature and multiple-path optical cell of the instrument permits ozone stratospheric conditions to be simulated. The true shape of the atmospheric absorption ozone line can be obtained by analyzing the solar flux with the spectrometer and its sun tracker. The concentration of stratospheric ozone versus altitude can be deduced by a synthetic spectra calculation and a nonlinear least squares fitting method.

A comprehensive compilation of improved line positions, intensities, and lower state energies has been generated for ozone between 0 and 3400/cm by combining the best experimental results with powerful theoretical methods. Various examples are presented which clearly show the improvements obtained with these new results compared to previously available line parameters. The importance of hot band absorption in atmospheric spectra is also demonstrated. It is shown that, without these new results, the first detection and measurement of the isotopic species (O-16)(O-16)(O-18) and (O-16)(O-18)(O-16) in the atmosphere by balloon-borne interferometer would not have been possible.

The SOIRDETE (Synthese d'Ouverture en Infra Rouge avec DEux TElescopes) infrared interferometry instrument at the Obervatoire de la Cote d'Azur in France is described. The basic principles of the instrument are set forth and the nature of the data it provides is explained. The design and operation mode of the instrument are examined together with its measurement procedure. A preliminary result from the instrument on Alpha Orion is reported which indicates the possible existence of an additional shell of dust surrounding the central star.

The setup and results of the experiment AROME to measure the 3.3 micron feature in diffuse galactic emission attributed to PAHs using stratospheric balloons are described. The main balloon project, Pronaus, consists of a 2 m telescope with two focal plane instruments: a submillimeter photometer dedicated to the measurement of very faint sources and a high resolution heterodyne spectrometer that measures water vapor and other species not observable from the ground.

The most recent projects in which the space research department of the Paris Observatory has participated are summarized. These include the Common User Near-Infrared CIRCUS (Camera Infrared Rouge Courtes longueurs d'onde pour Utilisation au Sol) camera, the adaptive optics COME-ON system, the High-Resolution Near-IR Camera for VLT, and the on-board IR 2D array camera of the ISO satellite, called ISOCAM. Technical characteristics and performance data for these instruments are listed.

The SAFIRE (Spectroscopy of the Atmosphere using Far-Infrared Emission) spaceborne instrument is discussed. The aim of SAFIRE is to improve understanding of the ozone distribution in the middle atmosphere by conducting global scale measurements of the important chemical, radiative, and dynamical processes which influence it changes. The SAFIRE FIR focal plane arrays are reviewed and the selection of photoconductive material, is examined. The Blocked Impurity Band (BIB) technology used in the detector is discussed. Finally, recent developments in Ge:Ga photoconductor stress technology are summarized.

A series of currently available IR detectors for astronomical observations are reviewed and various applications of the devices to instrumental astronomy are examined, emphasizing the parameters relevant to each of them. Emphasis is given to the 1-5 micron window critical to near-IR astronomy. Some recent results in this field are reviewed.

In a previous work, BSFR type silicon solar cells designed for space applications have been electrically tested under forward and reverse bias in a large temperature range (-30°C to 150°C), and their thermal behaviour simultaneously observed by infrared thermography. This study was done in order to know the highest reverse voltage a cell can be biased to, without damage caused by breakdown, and to follow the evolution of cell temperature during the breakdown development. In the present work, more realistic conditions of operation in space are imposed to a cell assembly bonded on a test sample representative of a solar generator structure, hung in a vacuum chamber (1 06 torr) equipped with a cryogenic wall and illuminated by an AMO 1 ,4 kW/m2 solar simulator through a window. Thermal analysis of the test sample is achieved using thermocouples and an infrared long wave camera viewing through a ZnSe window 45° tilted by reference to illumination axis. Partial shadowing of the solar cells can be introduced to simulate perturbations by antennas or other arms of the satellite. This cell shadowing can involve reverse biasing of a cell in a series assembly and cause local heating (hot spot) of the cell. Experiments have been conducted on two test samples, the first one equipped with two 20 mm x 40 mm BSFR cells, the second one, with nine cells of the same type. Results of this last experiment are presented, with attention paid to temperature measurements by IR thermography and thermal behaviour simulation of the system.

A comparison is made between stepwise and continuous scanning high-resolution Fourier transform spectrometers (HRFTSs) for the study of laser-induced fluorescence spectra of simple models in the infrared with a dense spectrum. The high-quality data show that the HRFTS is an excellent instrument for studying molecular structures from emission spectra. The stepwise instrument produces a better SNR in a given recording period.

We discuss the relative advantages of FT spectrometers over scanning instruments in the case of Raman spectroscopy in the near infrared. We also describe a conventional Raman laser installation especially designed for the near IR and we present some results obtained on fluorescent samples.

Far-IR transmission spectra of YBa23Cu3O(7-d) thin films have been obtained at 300, 80, 60, and 7 K, and the normal state transmissions have been calculated. The gap frequency is briefly discussed, and the low-temperature transmission in the superconductive phase at 7 K is calculated for the FIR range 10-200/cm.

An I.R. cell which can be used, in heterogeneous catalysis, as a continuous flow reactor up to 3 MPa and 575K is described. It is coupled to an on-line gas chromatograph for product analysis. It simultaneously allows recording the I.R. spectra of adsorbed species during the reaction, a pressed wafer being the catalyst. Using a FT-JR spectrometer, spectra can be recorded every 5 seconds. The system has been used to study different reactions such as i) n-hexane isomerization on H-mordenite and Pt-H-mordenite catalysts; ii) CO hydrogenation over Rh/CeO2 catalysts; iii) methanol synthesis on Cu-ZnAl2O4 catalysts with variable CO + CO2 + H2 feeds. Special attention has been paid to determine if the species which are observed are intermediates in the studied processes. In such a case, their detection provides very useful access to the reaction mechanisms. Moreover, the system allows us to follow the state of catalysts, under working conditions, for instance the degree of the zeolite deactivation or the reduction state of copper in the case of methanol catalysis.

Vibrational dissociation of hydrogen bonded complexes trapped in inert matrices at 10 K can be induced either upon selective infrared laser excitation or after broad band JR irradiation. Because of the rigidity of the host crystal the photodissociation corresponds to an internal reorganization of the complex, the new non hydrogen bonded form being metatastable and susceptible of a back transformation upon temperature increase or by tunneling. Kinetic measurements of the interconversion between the H-bonded (C) and non H-bonded (U) forms as a function of the temperature and irradiation domain allow conclusions to be drawn about the vibrational modes efficient for inducing the photoprocess and the energy barriers involved in the C &rlarr2; U interconversion. Two kinds of examples will be reported, one relating to hetero dimers of the type B:HJ, where B is a weak or medium strength base, the other to ammonia polymers. Comparison with recent predissociation studies in the gas and in the liquid phases evidences great similarities, in particular mode selectivity, whatever the physical state.

A mirrorless multiple path cell which can be efficiently used in the FIR is described. The device is based on the White cell and light pipe methods, and requires no setup even after cooling. It is shown how the system can be efficiently operated if certain geometrical conditions are maintained which ensure a uniform light energy distribution inside the cell. The optimization of some physical parameters is discussed, and it is shown that an effective absorption pathlength as long as 4 or 5 m can be obtained with a simple absorption cell which is 10 cm long. The FIR spectrum of CH4 obtained using the cell is presented.

Precise refractive index values of liquids have been obtained by an innovating method using two Michelson interferonieters. The first interferometer measures the variation of the optical pathlength in the liquid while the second controls the variation of the sample thickness. The present method may attain accuracies as high as iO- 1O6 for the refractive index values of liquids.

This facility has been operated since 1986 for the French laser matter interaction program at Limeil. It is the third most powerful laser system in the world. We will emphasize in this presentation the 1.06 micron performances of the facility, although it is mainly aimed at working for .53 and .35 micron plasma experiments1.

Work being done on solid-state lasers in a single laboratory is reviewed. Recent results on broadly tunable laser systems based on transition metal ions are addressed, discussing excited-state absorption measurements and the search for new emitting centers. The main emission spectra obtained with the rare earth doped laser materials Nd(3+), Er(3+), Tm(3+), and Ho(3+) are shown and discussed.

The photoresistive response of granular YBCO films on MgO has been monitored, and bolometric response times of a few 10 exp -8 s in the range 8-60 K have been obtained. At lower temperatures, the system behaves as if the electrons gradually decouple from the lattice. A two-temperature hypothesis qualitatively accounts for the observations.

The present status of SOFRADIR IRFPA technology is briefly reviewed. Sensitive arrays, readout circuits, interconnections, and dewar technologies are examined. Typical SOFRADIR products are listed, and production of these products is discussed, including the production center, production equipment, test equipment, and production yield. A manufacturing flow chart is shown.

Research conducted at ONERA to make quantitative infrared thermography operational and applicable to any 3D model is discussed. The problems of precise thermometry using this technique are considered, and the methodological and hardware choices made to obtain quantitative thermograms are described. The problem of determining the convective flows once the unsteady temperatures are known is addressed for two kinds of methods: classical passive thermography, in which only the heating due to convection is used, and active, or stimulated, thermography, in which the heat-transfer coefficients are calculated directly from the additional heating of the model by a radiation source, applied for short periods during the test.

This paper aims to illustrate the use of infrared thermography as a nondestructive and noncontact technique (a) to observe the physical processes of unstable crack propagation or flaw coalescence of engineering materials subject to various loadings, (b) to detect material defects or leakage phenomena and (c) to aid tribology experiments.

This study deals with the conclusions drawn from infrared thermal analysis experiments that were carried out over a period of several years. In the context of these experiments, we analyzed the aptitude of a system to switch between two functions an imaging and a measuring system for thermal flux. Temperature measurements were not dealt with in this analysis, as temperature readings introduce numerical values associated with material properties and radiative balance that are in no way characte ristic of infrared analysis. Our analysis deals with "single-detector" motion-picture cameras fitted with a "line/column" scanning system and with signal sampling on the amplified output of the detector. The image was thus reconstituted on a micro-computer, using the pixels from the sampling data, with a numerical depth determined by the digital convertor. This analysis was conducted within the constraints imposed by calibration procedures. These constraints are particularly severe when calibrating the spatial frequencies response function (within the frequency range). This calibration leads to a study of the image's structure and of its ability to produce output values that are of the same order of those produced by a measuring device.

The long-wavelength channel detector of Isocam, a camera aboard the Iso satellite designed to provide 32 x 32 pictures in the 2.5-5.5 micron and 4-17 micron bands, is discussed. The detector, readout circuit, and hybridization technology are addressed, and the main electrooptical measurements are reported. The spatial qualification of the device is briefly addressed.

Recent results obtained at LIR on PV detectors made on LPE layers and interconnected by metallic bumps to CCD silicon circuits are described. Test results are reported on 128 x 128 mosaics with 50 micron pitch detecting in the 3-5 micron wavelength rate at 77 and 200 K operating temperatures. The high quality and homogeneity of the CMT epilayers and the maturity of the photovoltaic and hybrid technology for large-size arrays are demonstrated, and the feasibility of operation at the above temperatures is shown.

The method described is based on emission-absorption of thermal radiation in the near infrared between 1 and 5 μm. Unlike conventional optical methods, it allows the determination of local temperatures rather than an average temperature integrated along aiming line of the pyrometer. The particle and gas temperature radial fields together with the relative particle concentration radial fields in a semi-industrial pulverized coal flame have been established. The distributions which have been obtained show that industrial flames are neither isothennal nor homogeneous. Particle and gas temperature profiles exhibit the same shape but particle temperatures are about 100°C higher than gas temperatures. Measurements have also been made with a suction pyrometer and the results obtained are generally found between those determined for the particules and gases respectively.

This paper is a follow-up of a paperl given in the 1980 SPIE Conference, "Modern Utilization of Infrared Technology VI". A brief review is given of the earlier paper describing the test target, "BTP#4". This target is used in estimating the effects of various image chain processes, particularly displays on intage quality for image exploitation. The paper then presents an abstracted version of a study2, "Effects of CRT Display Variable and Image Analysis" conducted by D. Heagy and R. Holmes in 1982. This study supports the hypothesis that the BTP#4 target scores can be used to evaluate the quality of a monitor for presenting images for exploitation. A correlation of .74 was found between average BTP#4 scores and image interpretability quality ratings on a monitor calibrated and set to 12 operating characteristics. The paper concludes with some examples of BTP#4 applications and coimuents on its advantages and disadvantages.

An overview of the increasing understanding of rocket plume phenomenology is given and selected recent observations are discussed. It is found that significant progress has been made over the last 10 yeats, but much needs to be done yet.

The thermal response of a surface layer of a pixel on an infrared target simulator is discussed. This pixel is maintained at a constant temperature by a rapidly scanning laser beam. An analytical model has been developed to describe the exact temperature dependence of a pixel as a function of time for different pixel refresh rates. The top layer of the pixel surface that generates the gray-body radiation shows the temperature dependence on time that is characteristic of a low-pass filter. The experimental results agree with the analytical predictions. The application of a pulsed laser beam to a noncontact, nondestructive diagnostic technique of surface characterization for the presence of microdefects is discussed.

The development of a PtSi array for use in ground-based astronomy has been the goal of a joint effort between the National Optical Astronomy Observatories (NOAO) and the Hughes Microelectronics Center. This has been accomplished by the introduction of the SWIR PtSi hybrid array for astronomy. The resulting array has an optical cavity tuned to enhance the internal quantum efficiency at 1.7 microns, low noise, and low dark current. The use of PtSi Schottky detector material yields high uniformity and exceptional stability of performance compared to other SWIR materials. Hybrid technology allows the array to achieve the 100% fill factor needed for astronomical applications and the NMOS SFD readout yields very low noise performance. In this paper we describe these characteristics in more detail and present test data to demonstrate the array performance.

A comprehensive computer code and a ratchet staring model for evaluating advanced electrooptical system are described and used to show how some of the different parameters of PtSi cameras affect total system performance. The performance of cameras predicted by these codes are compared with manufacturer-supplied data.

A two-dimensional 128 x 128 detector array for the 1.0 - 1.7 micron spectral region has been demonstrated with indium gallium arsenide. The 30 micron square pixels had 60 micron spacing in both directions and were designed to be compatible with a 2D Reticon multiplexer. Dark currents below 100 pA, capacitance near 0.1 pF, and quantum efficiencies above 80 percent were measured. Probe maps of dark current and quantum efficiency are presented along with pixel dropout data and wafer yield which was as high as 99.89 percent (7 dropouts) in an area of 6528 pixels and 99.37 percent (103 dropouts) over an entire 128 x 128 pixel region.

We have measured the noise factor and the gain of a high gain, low noise, large area hybrid detector for use at near infrared wavelengths (850-900 nm). The detector consists of an image intensifier tube optically coupled to a photomultiplier tube. Pulseheight analysis techniques enabled us to observe single photoelectron and dark electron events. We acquired pulseheight distributions using a pulseheight analysis system we designed based on a spectroscopy preamplifier and a spectroscopy amplifier/gated integrator with variable integration time. From these distributions we calculated noise factor and gain for the combined detector as well as its individual components. We found that the noise factors ranged from 1.89 at 5 kY bias to 1.64 at 9 kY bias. The gain also depended on the bias voltage with a maximum of 8x106 PMT anode electrons for every electron from the intensifier's photocathode at 9 kY bias. We compared our results to those obtained using conventional techniques and found that pulseheight analysis is a valid and useful method for characterizing devices.

This paper describes the successful completion of a long wavelength second generation infrared camera which was designed, fabricated and tested at Kolisman Co. The design focused on a low cost approach based on state-of-the art components which were sufficiently mature in their development cycle to be readily available if no design modifications were necessary (i.e. 'off the shelf'). The system design approach for the sensor package allows for retrofit to existing sensor platforms thereby reducing integration costs while offering second generation performance. The design is based on a 7.5-10.7 micron long wavelength focal plane array (FPA) consisting of 240 x 4 elements. Cryogenic cooling is supplied for the array using a state-of-the-art linear drive Stirling cycle refrigerator. The system is a parallel scanned type utilizing on-focal plane time delay and integration to achieve improved signal to noise ratio. Digital scan conversion is used to obtain RS-170 TV compatible output.