Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force Volume 3: Information in Warfare (1997) / Chapter Skim
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4 ADVANCED SENSORS
4 ADVANCED SENSORS
Pages 50-75
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From page 50... ...
In addition to providing new services and products, this industry will drive the development of low-cost, lightweight advanced sensors that will have spin-offs for uniquely military applications. In spite of the major contributions the commercial sector is likely to make toward satisfying future military sensing requirements, there will always be a subset of those requirements that has no identifiable, profitable commercial counterpart.
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From page 51... ...
Processing technology will enable surveillance coverage rates that are orders of magnitude higher than those achieved today. Wide-band communication via satellite or terrestrial channels will provide surveillance products on demand to warfighters in the field, who will be provided with the data storage and the tools necessary to take advantage of them.
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From page 52... ...
In fact, wartime conditions usually drive airborne platforms many tens of miles further back from the front once hostilities begin. As a consequence, airborne sensors are significantly limited in their ability to see deep into enemy territoryactive radar sensors because of limitations on power versus slant range, and passive imaging sensors because of loss of spatial resolution due to limited angular resolution.
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From page 53... ...
radar surveillance in support of theater missile defense. In general, providing surveillance for moving targets strains the ability to field affordable radar solutions from space because it requires a high revisit rate for near-continuous coverage.
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From page 54... ...
The total operational concept for the deployment of such surveillance systems must, however, be thoroughly understood. For example, the classical problem of providing radar surveillance of ground or airborne moving targets usually requires a radar with a certain power-aperture product in response to a requirement for target radar cross section and slant range.
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From page 55... ...
A standoff ground surveillance system could provide high-quality wide-area moving target detection, location, and target development, tasking the small systems to provide positive target identification based on cues from the "mother ship." The small systems could also complement the coverage of the standoff platform using LPI "spot mode" moving target indicator and synthetic aperture radar capability, together with intermittent operating protocols, to provide survivable focused surveillance of small areas, such as those screened from the large URAV by mountains. When cued by intelligence information to a narrow search area, this mode of operation could also be used to find deep targets out of range of the standoff system.
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From page 56... ...
Ship-based air defense radars will see a similar benefit in enhanced sensitivity as well as flexibility in the prosecution of multiple simultaneous fire control solutions. Exciter and receiver technology will achieve increasing levels of stability, permitting the detection of small moving targets in very-high-clutter backgrounds.
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From page 57... ...
Much is left to be done to achieve robust classification at low false alarm rates for targets partially screened by foliage or other obstructions, and targets deliberately camouflaged by an enemy to defeat the classifier. As sensor resolutions improve, yielding more pixels on target, and as processing technology continues to advance at its rapid pace, enabling more sophisticated algorithms to be employed, the performance of the classifiers will improve steadily, and should provide a very power
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From page 58... ...
Consequently, there is very little knowledge in the surveillance community about the potential benefits of moving target exploitation, and almost no prior body of knowledge on the subject. Moving target exploitation comes in several flavors, starting with the knowledge to be gained from the basic scan-to-scan detection picture obtained from a wide-area airborne ground surveillance system.
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From page 59... ...
profile of each moving target, providing a one-dimensional crude ATR capability as well as a powerful vector association variable for maintaining track continuity. All moving targets will be automatically tracked, and individual targets will be aggregated into groups based on various rule-based filtering criteria.
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From page 60... ...
The fusion of SAR change detection products and FOPEN radar products with MTI will provide a further enhancement to the long-term tracking of mobile targets. A major challenge in the surveillance component of this architecture is the target identification problem discussed above.
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From page 61... ...
The U.S. Air Force has successfully demonstrated reliable automatic target detection in airborne multispectral imagery in the visible through SWIR region.
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From page 62... ...
This hyperspectral measurement approach is enabled by the advances in large focal plane array (FPA) technology and can support the sensing of very narrow spectral features for specific target discrimination tasks or to enable adaptive measurement of fewer or coarser bands (through postdetection aggregation)
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From page 63... ...
spectral signatures, the active version will make use of lasers for illuminating scenes at specific wavelengths to interrogate their reflective spectral features. The primary driver for using active multispectral sensing is that, unlike passive sensors, the illumination and apparent reflectivities are not dependent on sun illumination and are not dependent on the thermal status of the target.
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From page 64... ...
Both color signature and differential absorption techniques could be used to perform identification of cloud or plume contents, but could also evaluate plumes via their shapes or dispersal patterns. Finally, active multispectral measurements can be coupled with additional laser discriminants to perform more thorough target identification.
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From page 65... ...
Electronic Beam Steering Optical sensors are currently burdened with heavy, complex, and expensive gimbals. Electronic optical-phased array technology has the potential to provide lightweight, agile, and simple beam-steering subsystems that not only can rapidly and accurately point a single beam but also can point multiple simultaneous beams.
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From page 66... ...
or spot sensors to provide either high-resolution or moving target imagery. Because of the high frame rate, video sensors are invaluable for detection of real-time change and motion.
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From page 67... ...
The designating platform might contain an imaging system to perform some functions; however, laser radiation would not be used to close the loop with the designator. The advantage of this system is that the laser power does not have to be boosted to compensate for the 1/(R2)
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From page 68... ...
The panel first considered the FPA developments that are likely due to the forces of market demand and next considered some of the emerging areas of technology development that are likely to occur due to related research and development. Commercial and Other Nonmilitary Market Demand Forces The demand forces of the commercial and nonmilitary marketplace will be responsible for technology improvements that will directly benefit military applications of focal plane arrays.
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From page 69... ...
The above applications are less affected by developments in the commercial sector since information processing techniques required to discriminate targets from background clutter and perform target identification must exploit unique signatures of the target and background. These unique characteristics include spatial and temporal features as well as electromagnetic wavelength and polarization.
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From page 70... ...
and false alarm probabilities. In the above application areas, the demand will be for multiband focal plane arrays (for spectral discrimination)
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From page 71... ...
This can be accomplished with very simple optical hardware. For example, the combination of a simple beam splitter and a second detector array, translated along the optical axis, further degrades the imagery with a known amount of defocus.
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From page 72... ...
Wavelength diversity has been demonstrated in simulation, although the algorithms are embryonic at this stage. As exploitation of multispectral data matures so that spatial resolution becomes more important, wavelength diversity will provide increased performance at no additional sensor cost.
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From page 73... ...
In the future, passive interferometric systems will also be used for several other purposes. One of these is to perform passive synthetic aperture three
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From page 74... ...
Geometrical path differences between the two optical paths cause the light to exhibit differential Doppler shifts. By examining the temporal content of the optical interferogram, one can readily measure the differences between stationary and moving targets to perform moving target identification with a passive multipleaperture system.
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From page 75... ...
Although the goal of "near-perfect knowledge" may never, in fact, be truly achievable due to fundamental physical limitations, removal of implementation limitations through advanced technology will nonetheless provide surveillance systems that will be dramatic force multipliers for future naval forces.
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