Granted Patent
Utility
US 5,790,474 · App. 07/391,835
Active sonar for under-ice conditions
Inventor:
Paul L. Feintuch
Patented Case
View Patent ↗
Granted: Aug 4, 1998
Filed: Aug 4, 1989
Inventor
Paul L. Feintuch
Assignee (at issue)
HUGHES ELECTRONICS LIMITED
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.