The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 02, 1985
Filed:
Mar. 18, 1982
Atul Jain, La Canada, CA (US);
Abstract
A synthetic aperture radar (10) is employed for .DELTA.k measurement of ocean current from a spacecraft (11) without the need for a narrow beam and long observation times. The SAR signal is compressed (12) to provide image data for different sections of the chirp bandwidth, equivalent to frequencies f.sub.1 (t.sub.a,t), f.sub.2 (t.sub.a,t) . . . f.sub.n (t.sub.a,t), and a common area for the separate image fields is selected (14). The image for the selected area at each frequency is deconvolved (16) to obtain the image signals for the different frequencies (f.sub.1, f.sub.2 . . . f.sub.n) and the same area. A product of pairs of signals is formed (18, 20), Fourier transformed (22) and squared (24). The spectrum thus obtained from different areas for the same pair of frequencies f.sub.jk, f.sub.j+n,k are added (26) to provide an improved signal to noise ratio. The shift of the peak from the center of the spectrum is measured and compared (28) to the expected shift due to the phase velocity of the Bragg scattering wave. Any difference is a measure of current velocity v.sub.c (.DELTA.k).