23 May 2013 Point source localization from de-ramped phase history bound on interferometric synthetic aperture radar (IFSAR) accuracy
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The almost unique ability of azimuth deramping to preserve a smooth phase function in azimuth is exploited here to link two disparate spatial processing methods, Direction of Arrival (DOA) localization and Interferometric Synthetic Aperture Radar (IFSAR) and explore the achievable accuracy inherent in their common measurement scenario. Deramping in range quickly provides a …rst component for point source localization. Deramping in azimuth is phase preserving and provides an approximate localization in azimuth that is more accurate over narrower apertures and can be corrected in scenarios involving range migration and for its point source, azimuth location dependence. In cross-track IFSAR two antenna measurements azimuth/elevation DOAs can be calculated from their smooth azimuth functions at each range with a 1 D parametric estimate (exponential model) of point sources. Joint frequency estimates (both antennae) provide the azimuth DOA while the phase di¤erence between antenna amplitude estimates provides the elevation DOA. The cross track antenna measurements can also be processed via the IFSAR methodology producing two SAR images and the phase di¤erence between the two (an interferogram). This provides two images coordinates and a height for each pixel. The connection between the phase history DOA localization and the IFSAR is used to attain accuracy bounds for IFSAR. Extrapolation of the bounds is provided from two spatially un-aliased antennas to IFSAR scenarios with large baseline separations of the antennas. In addition imaging from the azimuth-elevation-range localization data and its ability to minimize layover (building tops imaged closer than their bases) is explored.
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Matthew Pepin, Majeed M. Hayat, "Point source localization from de-ramped phase history bound on interferometric synthetic aperture radar (IFSAR) accuracy", Proc. SPIE 8746, Algorithms for Synthetic Aperture Radar Imagery XX, 874605 (23 May 2013); doi: 10.1117/12.2015782; https://doi.org/10.1117/12.2015782

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