Accession Number : ADA310740

Title :   Three Dimensional SAR from Curvilinear Apertures.

Descriptive Note : Progress rept. Oct 93-Oct 94,

Corporate Author : NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD SIGNATURES DIRECTORAT E

Personal Author(s) : Knaeil, Kenneth

PDF Url : ADA310740

Report Date : JAN 1994

Pagination or Media Count : 39

Abstract : Three-dimensional (3-D) radar imaging is presently at an exploratory stage of development. Such imagery is of proven usefulness and would undoubtedly find increased application if more readily available. The 3-D information content in data taken from a curved SAR aperture is significant if sizable data projections are produced when the date are projected in three orthogonal directions. Such sparce data does not generate visually acceptable 3-D images by straight forward Fourier transformation however. The high sidelobes present in such images may be larger than major scatterers and thus veil their appearance and they also very nearly always interfere with visual lines of sight to other scatterers. A coherent adaptation of the CLEAN algorithm is shown to be very effective in eliminating sidelobes in such images allowing the 3-D character of the target to be observed. Images obtained for a target consisting of eight corner reflector scatterers within several resolution distances of one another show only moderate dependence upon the aperture chosen. Comparison of results from real and simulated data indicate that the dynamic range available was not limited by sidelobe interferences in the subtractive deconvolution process but was inherent in the data in this experiment. These results indicate that it may be possible to form visually useful 3-D images of targets in an operational situation from SAR data taken along a curvilinear aperture path.

Descriptors :   *SYNTHETIC APERTURE RADAR, ALGORITHMS, SIGNAL PROCESSING, FOURIER TRANSFORMATION, LINEAR SYSTEMS, SIMULATION, SCATTERING, FORWARD AREAS, COMPARISON, RESOLUTION, COHERENCE, ORIENTATION(DIRECTION), RADAR IMAGES, THREE DIMENSIONAL, INTERFEROMETRY, ADAPTATION, APERTURES, ORTHOGONALITY, SIDELOBES, DYNAMIC RANGE, CURVES(GEOMETRY), CONVOLUTION, CORNER REFLECTORS.

Subject Categories : Active & Passive Radar Detection & Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE