Discrete autofocus for ultra-high resolution synthetic aperture radar
CA 2003469 C · Owner: Hughes Aircraft Company · Inventors: Niho, Yoji G.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention provides improved focus by phase corrections for Synthetic Aperture Radar images by operation on the range bin containing a selected isolated target. A phase correction signal is generated by first obtaining a non-interfering radar return from the selected target through band pass filtering operation and then extracting a non-linear residual phase from the band pass filtered data with an arctangent generator. The residual phase derived by the arc-tangent generator is then applied to the range compressed SAR data as a phase correction signal.
Read the whole patent
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 November 21, 1989 and granted November 8, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 21, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 21, 2011.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.