Abstract- I. INTRODUCTIONConventional synthetic aperture radar (SAR) requires sufficient integration time to generate pixels that are roughly symmetric in the range and cross-range dimensions. Pixel deviations from perfect symmetry (ellipticity) are normally considered undesirable because human visual perception is optimized for images consisting of round pixels. As pixel ellipticity increases, image interpretability by human operators decreases. However, in conventional SAR, useful moving target effects noticeable over short processing intervals can be significantly suppressed unless extensive target-specific motion compensation techniques are applied. The most noticeable form of moving target degradation is caused by range walk, wherein the signal returns from moving targets successively "walk" through many adjacent range/cross-range pixels during the image data collection time interval, causing substantial target blurring.Without some form of motion compensation, SAR images experience significant range walk and be quite blurred. In 1997, MITRE reported development of the Keystone Process [1].Keystone Formatting simultaneously compensates for multiple target motion at multiple radial velocities. Thus no matter what radial velocity the target is moving at, it will remain in a given range cell determined by its position at the center of the coherent processing interval.Coherent processing of the data without any compensation for target motion results in an integration loss and smearing of the target over multiple range cells. Standard motion compensation will only correct the range walk for one target at a time. The Keystone process compensates for the motion of all the targets simultaneously. (See Figure 1).Further, the SAR data has to be acceleration-compensated to produce focused images. Since each target may have a different acceleration, the moving targets can be individually and automatically focused after detection using the procedures previously reported in [1].The target motion causes the moving targets to appear at locations different from their true instantaneous locations on the ground. This is due to the coupling of the cross-range position to the target radial velocity and the fact that the moving target and the ground under it have different radial velocities relative to the platform. The result is the well known 'train off the track' or 'boat off the wake' phenomenon (Figure 2). Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwi...
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