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:
Dec. 03, 1991
Filed:
Nov. 08, 1990
Applicant:
Inventors:
Christopher Lewis, Isle of Wight, GB;
Robert J Barton, Isle of Wight, GB;
Assignee:
Siemens Plessey Electronic Systems Limited, Ilford, GB;
Primary Examiner:
Int. Cl.
CPC ...
G01S / ; G01S / ;
U.S. Cl.
CPC ...
342 90 ; 342192 ;
Abstract
A pulse doppler radar system for helicopter recognition has a receiver (5) for receiving reflected pulse radar signals. A distinguishing circuit (22) is provided for distinguishing a group of received frequencies within a predetermined spectral range and for ignoring at least the largest amplitude frequency within that group. A threshold detector (24) is arranged to determine when the amplitude of the remaining frequencies in the group exceed a predetermined value to provide a recognition signal.