Title :
Space variant filtering of polar format spotlight SAR images for wavefront curvature correction and interferometric processing
Author :
Preiss, M. ; Gray, D. ; Stacy, N.
Author_Institution :
Defence Sci. & Technol. Organ., Edinburgh, SA, Australia
Abstract :
In repeat pass SAR interferometry the scene coherence can be used to detect subtle scene changes that occur in the interval between image collections. In spotlight SAR mode the azimuth resolution of the baseline and repeat pass imagery may be improved by collecting an extended aperture therefore allowing finer resolution estimates of the scene coherence. The formation of the imagery however requires adequate compensation of the wavefront curvature effects which become increasing significant in finer resolution imagery. In N. E. Doren (1997) it is shown that for spotlight SAR imagery, formed using the Polar Format Algorithm (PFA), wavefront curvature effects give rise to residual phase errors that may be removed using an image domain filtering technique. The analysis however is based on the formation of a slant plane image obtained by projection of the scene reflectivity along circular arcs centered on the flight track. In this paper a full 3D imaging geometry is considered to derive an appropriate post PFA image domain filter to form a ground plane image. This allows multipass images to be formed in a common image plane for subsequent interferometric processing. The technique is used to generate a fine resolution coherence map using data collected in a repeat pass SAR experiment using the DSTO Ingara SAR.
Keywords :
geophysical signal processing; geophysical techniques; radar imaging; radar signal processing; remote sensing by radar; synthetic aperture radar; terrain mapping; 3D imaging geometry; InSAR; SAR; geophysical measurement technique; image domain filtering; interferometric processing; land surface; polar format algorithm; polar format spotlight SAR images; radar remote sensing; repeat pass SAR interferometry; residual phase errors; scene changes; scene coherence; slant plane image; space variant filtering; spotlight SAR; synthetic aperture radar; terrain mapping; wavefront curvature correction; Apertures; Azimuth; Coherence; Filtering algorithms; Geometry; Image analysis; Image resolution; Interferometry; Layout; Reflectivity;
Conference_Titel :
Geoscience and Remote Sensing Symposium, 2002. IGARSS '02. 2002 IEEE International
Print_ISBN :
0-7803-7536-X
DOI :
10.1109/IGARSS.2002.1024980