Auto-focusing correction for rotational acceleration effects on inverse synthetic aperture radar images
CA 2128683 C · Owner: Lockheed Martin Corporation · Inventors: Hatlestad, John David; Farmer, Michael Edward
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Inverse synthetic aperture radar imaging systems that are used to image targets that undergo rotational accelerations are enhanced by signal processing techniques which provide correction factors to reduce the frequency-shift and frequency-stretch errors that occur due to such accelerations. A target scan is subdivided into a number of sub-apertures and a Fast Fourier Transfer (FFT) is performed on the data for each subaperture to provide associated frequency sub-images. The FFT is then subdivided in "sub-swaths" of amplitude versus frequency for a plurality of frequency bands. The change-of-frequency, or frequency shift data between, prominent scattering points of each sub-image are …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed July 22, 1994 and granted April 9, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 22, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 22, 2016.
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.