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Title: Radar transponder apparatus and signal processing technique

An active, phase-coded, time-grating transponder and a synthetic-aperture radar (SAR) and signal processor means, in combination, allow the recognition and location of the transponder (tag) in the SAR image and allow communication of information messages from the transponder to the SAR. The SAR is an illuminating radar having special processing modifications in an image-formation processor to receive an echo from a remote transponder, after the transponder receives and retransmits the SAR illuminations, and to enhance the transponder's echo relative to surrounding ground clutter by recognizing special transponder modulations from phase-shifted from the transponder retransmissions. The remote radio-frequency tag also transmits information to the SAR through a single antenna that also serves to receive the SAR illuminations. Unique tag-modulation and SAR signal processing techniques, in combination, allow the detection and precise geographical location of the tag through the reduction of interfering signals from ground clutter, and allow communication of environmental and status information from said tag to be communicated to said SAR.
 [1];  [1];  [1]
  1. (Albuquerque, NM)
Issue Date:
OSTI Identifier:
United States of America as represented by United States (Washington, DC) SNL
Patent Number(s):
US 5486830
Contract Number:
Research Org:
Country of Publication:
United States
radar; transponder; apparatus; signal; processing; technique; active; phase-coded; time-grating; synthetic-aperture; processor; means; combination; allow; recognition; location; tag; image; communication; information; messages; illuminating; special; modifications; image-formation; receive; echo; remote; receives; retransmits; illuminations; enhance; relative; surrounding; ground; clutter; recognizing; modulations; phase-shifted; retransmissions; radio-frequency; transmits; single; antenna; serves; unique; tag-modulation; techniques; detection; precise; geographical; reduction; interfering; signals; environmental; status; communicated; aperture radar; signal processor; signal processing; processing techniques; signal process; special process; ground clutter; formation process; surrounding ground; processor means; processing technique; /342/