The importance of remote sensing for high-rate, high-accuracy position feedback in the control of large flexible structures is gaining wide recognition. Less obvious is the equally important use of these sensors for target tracking, proximity sensing, systems identification, and other control-related applications. The remote attitude measurement sensor (RAMS) can be easily adapted to satisfy each of these applications by selecting the optical components to meet specific measurement needs. The RAMS system has been configured to accept many different lens/target combinations and thereby provide versatility, easy of use, and reliable performance. Examples of typical applications are provided, along with descriptions of the sensor configurations and performance. Recent experiences in RAMS hardware development and testing are also described, including the use of RAMS for the Control, Astrophysics, and Structures Experiment in Space (CASES) Advanced Development Facility (ADF) and the controls-structures interaction demonstration experiment (C-SIDE).

A near-UV and near-IR image mixing technique capable of clearing peculiar details of the scene and determining relative ranges between the different elements without any degradation in the spatial resolution is described. Several pictures were recorded in these two spectral regions, then they were digitized, and mixed together. A red-green-blue balance was used to obtain a pseudo-color image.

An accuracy requirement of ±0.011 degrees in the declination measurement of a remotely imaged munition cannot be satisfied using a conventional camera. A camera, error characterization, and error correction techniques are designed and developed that satisfy the accuracy requirement. The images are acquired and processed using an ARDEC developed data acquisition and image processing system. Based on internal testing, the developed system is expected to meet design goals during a formal certification process.

Time-Delay and Integration (TDI) CCD sensors have been proven to increase the effective sensitivity in imaging applications where the image is scanned across the focal plane. This paper describes the development of a 6032 element, 32-stage TDI imager for airborne reconnaissance applications. The device is fabricated using a 3-poly 3-phase NMOS process, incorporating buried channel CCDs throughout. It is one-side buttable to produce an array of over 12,000 contiguous elements and is capable of read rates of over 4000 lines per second. For fast readout, the design incorporates dual horizontal CCDs for a total of four outputs in the abutted configuration. The architecture also allows dynamic selection in the number of TDI stages.

Two major technological developments have benefited stars sensors in recent years: the charge-coupled device (CCD) detector and the microprocessor. The ASTRA-1 star tracker developed by Hughes Danbury Optical Systems, Inc. (HDOS) is a CCD, microprocessor-based replacement for the NASA Standard Fixed Head Star Tracker. This paper will provide an overview of the measured performance of the ASTRA-1 star trackers delivered to Fairchild Space Company for use on the TOPEX/POSEIDON mission scheduled for July 1992.

Stellar imaging systems require complex focal plane device structures to perform the basic functions of detection time - delay-and-integration (TDI) and scanning in field of large array formats. Charge coupled devices (CCDs) are the regular structure for scanning system focal planes which utilize principle TDI. A star sensor making use a linear and matrix CCD-TDI imaging processing system is presented.

In fogging, using laser and CCD sensor (charge coupled device) measuring, because of scattering effect to laser and other light, the output signal from CCD is not stable and make errors. For example, measuring the diameter of cable by laser and CCD on vulcanization line, there is vapor around cable, so it can produce water bead and line on cable and window used to observe. The fogging and water make the measure result neither stable nor accuracy. A special signal processing method of CCD which combines soft-ware with hard-ware is deeply discussed in this paper. The experiment has proved that this method to measure the diameter of cable is absolutely feasible and very successful.

Hardware design based on 20 MHz transputers, 120 ns first-in, first-out (FIFO) memory, and a 20 MHz counter is discussed. The two transputers are used to generate the states and to write them into the FIFO memory. The data generated by the transputers is written in the FIFO memory in parallel. The system design is characterized by a minimal state of 100 ns, a resolution of 33.3 ns, and fast data rate generation.

Back-illuminated, 16-port 512 X 512 and 32-port 1024 X 1024 charge coupled device (CCD) imagers have been fabricated. The measured performance of the 512 X 512 pixel chip is described, including data on quantum efficiency, dynamic range, dark current, frame rates, uniformity, contrast transfer function, and on-chip correlated double- sampling (CDS) amplifier noise. We have previously reported on these designs. The CCD arrays are designed with a unique combination of parameters optimized for applications requiring high resolution combined with high frame rates and wide dynamic range. The imaging registers achieve 100% optical fill factor and high quantum efficiency through the use of substrate thinning and back-side illumination. The high frame-rate readout is obtained by the use of a dual storage register and multiple floating-diffusion output ports which reduce the 512 X 512 array readout frequency to 15 MHz for 800 frame per second operation. On- chip CDS amplifiers are included in each output port to reduce the readout noise and simplify off-chip analog signal processing. Both designs include a buried anti-blooming drain structure and electro static discharge (ESD) protection.

This paper describes a programmable timing generator designed and built to provide timing for focal plane arrays. The timing generator hardware consists of a plug-in board for a PC/XT/AT/386/486 personal computer. The board features 24 output channels, data rates from 175 Hz to 10 MHz, two levels of nested looping, and allows the bit rate to be changed while routine is being executed. Associated software includes a pattern editor, timing routine compiler, memory loader, and generator controller. The board has been successfully used to operate a 4 X 138 X 128 HgCdTe infrared array, a 2098 X 3 linear CCD array, and a 1024 X 1024 full-frame readout CCD. Although intended for use with focal plane arrays, the timing generator can be used in any application where multiple channels of complex and repeated timing are desired. For example, it was used to emulate a TMSC30 digital signal processor serial interface. The timing generator and associated software has proven to be easy to use, and take advantage of the PC/XT/AT/386/486 compatibility and popularity. The board is inexpensive due to the use of standard CMOS logic and one programmable gate array. The programmable part allows the design to be easily upgraded. Future plans include an upgrade to 3 levels of looping.

focusing on work on large device formats, improvements in quantum efficiency, and reduction of CCD degradation in the natural space-radiation environment. Research was based on a 420 x 420-pixel frame-transfer device and a new 1024 x 1024-pixel device. To obtain high quantum efficiency from the visible into the UV, a technology for making back-illuminated versions of these devices is being developed. Quantum efficiencies greater than 80 percent in the 500-800 nm band have been obtained with a SiO antireflection coating. Particular attention is given to the problem of charge-transfer inefficiency degradation caused by energetic protons in space-based systems. It is shown that CCDs can be significantly hardened to radiation effects by a combination of special buried channel potential profiles and operation at temperatures around 150 K, where the trap sites created by the protons have emission times much longer than the clock periods.

A model of back illuminated CCDs is presented that concentrates on the fields that can exist at or near the illuminated surface. The parameters that influence these fields and how they affect the device quantum efficiency are explored. We also present a design for a thinned CCD using ion implantation and KrF excimer laser anneal that is tuned for enhanced UV response.

Detector arrays made with polysilicon gate charge-coupled device (CCD) technology have been used as visible imaging sensors for many years. The sensitivity of these detectors is limited by the absorption of incident energy in the polysilicon gate electrodes which prevents it from reaching the bulk silicon body of the device. In order to overcome the limited optical transmission of polysilicon films, electrically conductive, optically transparent films of tin oxide have been employed as gate electrodes for CCD visible imaging detector devices. With a quantum efficiency of 85% in the mid range of the visible spectrum, these front side illuminated arrays offer superior sensitivity over devices fabricated with polysilicon gate technology. The use of tin oxide as the gate material imposes several constraints on the CCD device structure and the fabrication process technology. These constraints include limits on processing temperatures and the ambient to which the material can be exposed during processing. This presentation will describe the technology used to fabricate tin oxide gate CCD devices as well as design considerations for both staring and TDI scanning devices. Both open pinned phase and four phase device architectures will be discussed.

Spreading a picture on a cylindrical object is presented. After alignment which utilizes correlation for determining automatically the width of each snap, the summarized picture is displayed.

The core concept developed here is one of digital registration of multiple frames of moderate resolution from such readily available recording sources as palm VCRs. The multiple frames are then coalesced into a single frame of highly sampled imagery to increase the critical Nyquist sampling rate in regions of interest. To achieve the highest resolution of the final product, special data driven spatially varying image enhancement techniques are the employed. Both mathematics and results are shown.

As a part of the MIT Lincoln Laboratory Critical Mobile Target program an experiment was conducted jointly by the Jet Propulsion Laboratory and MIT Lincoln Laboratory in July 1990 using the NASA/JPL airborne SAR system, to investigate the effects of foliage on Synthetic Aperture Radar (SAR) imaging of targets concealed by trees. A large number of 8-ft corner reflectors were deployed for the investigation of two-way propagation through foliage, and tone generators were deployed at four locations to investigate one-way pulse-to-pulse phase and amplitude fluctuations to study possible SAR beam distortions caused by trees. In addition, a 40 km² area was imaged over five passes at each of 30 degree(s), 45 degree(s), and 60 degree(s) depression angles, simultaneously at C-, L-band and UHF frequencies, fully polarimetrically. Several trucks of varying sizes were also deployed in the open and behind trees for limited testing of target detection. Analysis of the data is near completion. This paper will summarize results on attenuation and clutter statistics, SAR pattern distortion through trees as well as results on multichannel processing of the images containing vehicle masked by foliage.

Exploitation of commercial multispectral satellite imagery (e.g., Landsat Thematic Mapper (TM) and SPOT multispectral scanner) can be extremely useful for surveillance and broad area search due to the large geographic areas covered with each orbital pass. However, most multispectral sensors are not designed for the specialized tasks associated with surveillance. As a result, multispectral exploitation for surveillance faces significant technical problems. Principle among these problems is the low spatial resolution of the sensor. This paper presents an innovative technique that synergistically fuses high resolution panchromatic imagery with lower resolution multispectral imagery to generate a 'sharpened multispectral image', which is an estimation of high resolution multispectral information. This is a two stage paradigm where an initial estimate of the sharpened image is made using the pseudoinverse and then refined using a set of fuzzy rules. The pseudoinverse produces a minimum mean-squared error estimate of the sharpened pixel while the fuzzy rules refine this estimate using the local information contained in the surrounding pixels. This technique and preliminary processing results are presented. Implications for surveillance is also discussed.

This paper describes the work completed by Martin Marietta in support of the U.S. Army's standoff minefield detection system, advanced technology transition demonstration. This paper discusses the high priority and urgent need for the standoff mine detection system within the Army Combat Engineers, it presents the results of the successful application of non developmental technology/hardware in an airborne mine/minefield detection system, and it discusses the significant payoff of applying advanced ATR and high speed parallel processing. The technologies discussed include the IR imager as the source of mine imagery, advanced image processing algorithms including neural nets, and a high speed parallel processor unique to Martin Marietta called GAPP (geometric arithmetic parallel processor).

One requirement of an endoatmospheric interceptor window system is to allow the seeker to collect sufficient energy for object detection. The capability to collect energy can be significantly affected by the design of the wind and its accompanying support structure. The Segmented Window Analysis Program (SWAP) has been developed and validated as a flexible computer program for use in determining the transmission of various segmented window designs. Forty-six window configurations consisting of various window materials and structure designs were used in an experimental validation of the SWAP code. A direct comparison of over 1200 data points was made between the experimental data and the SWAP predictions, with an average difference of 1.68 percent. The algorithms were then exercised over a larger range of inputs to parameterize the performance of a generic window design as a function of the established variables. In general segmented window designs can be optimized by using high index of refraction materials, minimizing support width and minimizing support thickness. While some factors have a greater impact on the performance of the window system than others, an overall design optimized for throughput must be based upon a particular sensor's operating conditions and requirements. Specifically, we have shown that there are conditions where a wide range of window thicknesses and segment sizes perform nearly identically. Other issues, such as thermal, mechanical, and imaging requirements, while not considered in this study, must be included in the final design.

Both thresholding and windowing are important tools in the reduction of false alarm rates in high sensitivity point source detection and correlation sensor signal processors. In a variable background environment, adaptive thresholding is required to maintain a constant false alarm rate, and in a variable target environment, adaptive windowing is helpful in controlling false alarm rate, while maintaining correlation performance. Several issues arise when applying adaptive detection thresholding and windowing in a scanning infrared sensor processor. Choice of control loops for both thresholding and windowing should be such that instabilities caused by interactions between them are minimized. Instabilities in operation can also occur due to the various states of the system itself, such as scanning state changes or gain mode changes. The current presentation will describe the application of adaptive thresholding and windowing in the sensor subsystem design of the Airborne Surveillance Testbed. Control loop closure choices will be outlined for both thresholding and windowing, and their effect on false alarm rate and correlation will be covered. The correction of scanning state and gain mode effects on thresholding will also be addressed, as well as the impact on correlation performance.

The spectrally agile staring sensor (SASS) is an instrument system that is able to get image and spectrum information. This paper analyzes the expression of signal-to-noise ratio and overall performance of the SASS system that uses an acousto-optic tunable filter as its spectral filter, and points out improving methods and limiting factors of the system performance. The complete SASS system experimental set-up is constructed. Using this set-up, the theory is verified, and the image and spectrum information of the simulated target is acquired.

The author selected fuzzy-logic motion control (MC) that is propulsion and/or guidance and/or suspension control algorithms to the mechatronically controlled Intelligent Mobile (IM) small all-weather & all-terrain Surveillance Unmanned Autonomous Vehicle (SUAV). Fuzzy logic was chosen because it is easier to implement human driver (HD) skills using fuzzy-logic MC than using conventional MC algorithms. It filters even the uncertainty of the precision of the sensors. Therefore, the SUAV may move as smoothly as a well-skilled or experienced HD being along straight and curved routes on the hostile location or battlefield. MC for a SUAV requires many of the same elements that the military Command Control Communication and Intelligence system use. The IM small all-weather & all-terrain SUAV will have two types of moving mode-IR vision-camera mode and US sonar mode-originating from the differing methods used to detect the SUAV position.

The performance of the Lightning Mapper Sensor is dependent on the temperature shifts of its narrowband spectral filter. To perform over a 10 degree FOV with an 0.8 nm bandwidth, the filter must be 15 cm in diameter and mounted externally to the telescope optics. The filter thermal control required a filter design optimized for minimum bandpass shift with temperature, a thermal analysis of substrate materials for maximum temperature uniformity, and a thermal radiation analysis to determine the parameter sensitivity of the radiation shield for the filter, the filter thermal recovery time after occultation, and heater power to maintain filter performance in the earth-staring geosynchronous environment.

The Visible Ultraviolet Experiment sensor was successfully flown on a Defense Support Program satellite at geosynchronous orbit. This paper discusses the thermal design employed for the sensor which was mounted on the rotating DSP platform. The most critical thermal design problem involved maintaining an isothermal telescope temperature. Thermal performance data is presented showing that observed performance is in good agreement with predicted performance.

A SiC based telescope is an extremely attractive emerging technology which offers the lightweight and stiffness features of beryllium, the optical performance of glass to diffraction limited visible resolution, superior optical/thermal stability to cryogenic temperatures, and the cost advantages of an aluminum telescope. SSG has developed various SiC mirrors with and without a silicon coating and tested these mirrors over temperature ranges from +50 C to -250 C. Our test results show less than 0.2 waves P-V in visible wavefront change and no hysteresis over this wide temperature range. Several SSG mirrors are representative of very lightweight SiC/Si mirrors including (1) a 9 cm diameter, high aspect ratio mirror weighing less than 30 grams and (2) a 23 cm diameter eggcrated mirror weighing less than 400 grams. SSG has also designed and analyzed a 0.6 meter SiC based, on axis, three mirror reimaging telescope in which the primary mirror weighs less than 6 kg and a 0.5 meter GOES-like scan mirror. SSG has also diamond turned several general aspheric SiC/Si mirrors with excellent cryo optical performance.

A critical technology area for lightweight SiC-based telescope systems is the structural integrity and thermal stability over spaceborne environmental launch and thermal operating conditions. Note, it is highly desirable to have an inherently athermal design of both SiC mirrors and structure. SSG has developed an 8 inch diameter SiC telescope system for brassboard level optical and thermal testing. The brassboard telescope has demonstrated less than 0.2 waves P-V in the visible wavefront change over +50 C to -200 C temperature range. SSG has also fabricated a SiC truss structural assembly and successfully qualified this hardware at environmental levels greater than 3 times higher than normal Delta, Titan, and ARIES launch loads. SSG is currently developing two SiC telescopes; an 20 cm diameter off-axis 3 mirror re-imaging and a 60 cm aperture on-axis 3 mirror re-imager. Both hardware developments will be tested to flight level environmental, optical, and thermal specifications.

The type of structure and thermal control system for a radiometer operating in a GEO environment are considered, focusing on design considerations for pointing stability and radiometric calibration. It is pointed out that the thermal control system and the structural design must be compatible. They must both strive to reduce distortion due to thermal expansion and contraction. The thermal control system design must minimize both maximum temperatures and temperature variations. The structural design must minimize the structure response to temperature changes.

A research project intended to design and fabricate a dimensionally stable 2 mu spherical mirror 0.4 m in diameter, carried out by Composite Optics, Incorporated, is briefly reported. A laminate for the facesheet and the back surface that is intended to be exceptionally uniform in-plane has been designed using the P75/ERL 1999 material. The core is designed to be pseudoisotropic in all three directions.

This paper will address the design considerations and challenges for a radiometer scanning mirror in a Geostationary (GEO) orbit. With increasingly demanding imaging requirements, mirror designs that are insensitive to the harsh thermal environment will be required. The compatibility of various mirror designs for a precision radiometer will be examined and discussed. The design solutions considered will include material, geometry and thermal design tradeoffs.

A critical component of IR sensors is the infrared detector. In order to predict sensor performance, a step-function optical response is typically assumed. This model is then used to predict overall sensor performance and to optimize signal processing algorithms. However, pixels rarely exhibit this ideal behavior. Two deviations in ideal response are described: a pixel center region degradation and an exponentially decaying region on the outside of the pixel corresponding to carrier diffusion. The corresponding MTFs are calculated and the effect on matched filters and sensor performance is modeled.

A PEARLSS (Particulate Effects Analysis on Response Levels of Spaceborne Sensors) approach is presented with particular attention given to the code structure and on-going code developments. PEARLSS is a system response simulation which models the degradation of sensor performance due to particulates in the near field-of-view and deposited on optical surfaces. This flexible, modular code is aimed at performing parametric studies on design parameters including sunshade geometry, system materials, temperatures, prelaunch cleanliness levels, and pointing directions.

When you are designing an advanced optical system thre are several problems to consider. The optical concept has to enable a reasonable mechanical design with respect to size, mechanical stability and mounting of optical components. The optical design has to be checked for interference between rays and mechanical parts. The optical components have to be individually optimized for an appropriate size of the optical surface. In this paper it is shown how a CAD system can simplify the optical design. An interface program has been developed to be used together with an optical program and a 3D CAD system. The interface program can read optical data files, alter the data if required and output ray coordinates to the CAD system. The rays can be drawn in 2D from different views or generated as 3D volumes.

It is well known that the ocean has enormous important for human life. The Ocean Color Imager is going to be one of the most important optical remote sensors on the ocean satellites, with missions to survey the distribution of suspended sediment, phytoplankton, and chlorophyll. The latter two items will be used to evaluate the primary productivity of ocean. China is a country with a long coastline and large territorial ocean remote sensing is very important. Changchun Institute of Optics and Fine Mechanics (CIOFM) is studying a prototype Ocean Color Imager to determine its feasibility and applications. It is expected that the visible near infrared region (0.4 - 1.06 micrometers ) Ocean Color Imager will have a spectral resolution of 10 to 20 nm, a spatial resolution of about 1 km and a global coverage period of two to three days from an orbit 700 to 900 km in height.

The suggested algorithm and propose construction of an electro-optical system provide an abrupt drop in information flow in a situation like global visioning of the earth's surface. An estimation of the efficiency of this algorithm gives the data flow compression in the vision system by a factor of 10³ - 10⁵. Initial experiments confirm the basic principles of this proposal.

This paper describes a new focal plane evaluation system based on the IBM 386 PC. It has been used to evaluate three devices--a 4 X 128 X 128 pixel SWIR array, a 2098 X 3 linear CCD used as a panoramic camera, and a 1024 X 1024 MPP split frame CCD. Results and images from each are presented. The system includes a word generator implemented as a single PC/AT card, which generates all the complex looping timing signals required for focal plane operation and data acquisition. The word generator is described more fully in a companion paper. Software simulates a popular 'subpattern' style of timing editing. A commercial analog data acquisition module on a single PC/AT card, and software are used to acquire, pre-process and display up to four channels of an image at pixel rates to 1 MHz, continuously up to the extended memory limit of the 386, many Mbytes. Commercial image processing software is used to further process and display images. The system has proven to be powerful, easy and fast to use, flexible, transportable, and yet inexpensive due to the choice of the PC as its base.

A planned and integrated geophysical approach, using all available data, has proven effective in detecting shallow tunnels and buried objects in different geological environments. Elements of the integrated approach included information from intelligence, historical reviews, computer modelling, and multiple geophysical survey methods. The use of the integrated approach resulted in a higher rate of success in detecting tunnels and small objects at shallow depths; however, no single survey technique has been universally effective. Several different survey methods were used to determine specific characteristics of a potential target. Magnetic sensors detected ferromagnetic materials used in tunnel construction. Analyses of the magnetic anomaly characteristics and the surface patterns of the anomalies indicated the depth and path of the tunnel. Tunnels were also detected by intrinsic parameters of observed electromagnetic anomalies and the surface patterns of instrument responses. Both methods have successfully differentiated materials used in tunnel construction and operational support systems from surface features such as utility or sewer lines. Cross-borehole radar was used to confirm the existence of a deep tunnel through crystalline rock in the southern part of the Demilitarized Zone in the Republic of Korea. Additional indications of tunnels were obtained from analyses of migrated seismic compression waves (P-waves) collected by a vertical stack, common- midpoint method. Ground-penetrating radar (GPR) and magnetic and EM sensors were effective in detecting shallow-depth caches constructed of various materials.

In the last 15 years, law enforcement efforts have fallen behind in the area of technology. Narcotic traffickers and suppliers have vast amounts of monies to subvert law enforcement counter narcotic efforts. With this money, narcotic offenders have been able to develop, purchase and utilize technological and scientific measures to further their drug trade. These advances range from simple radio scanners to scientific process to alter drugs until they are ready for distribution. Law enforcement effort needs the assistance of these technological advances to hold the line on narcotic enforcement.

The design and preliminary evaluation of a low cost video based multispectral camera system developed in the Standoff Mine Detection Ground (SMDG) exploratory development project for the US Marine Corps is described. The system is composed of an intensified and gated video camera fitted with six user selectable filters in a synchronous spinning filter wheel which provides a different spectral filter for each video frame. The camera system is microprocessor controlled for automatic exposure and matched with custom designed spectrally corrected optics. The associated analog and digital image storage and processing equipment and techniques are also discussed. This system has been field tested to detect land mines at long standoff distances.