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:
Sep. 01, 1998
Filed:
Nov. 05, 1997
Isao Yamaguchi, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A synthetic-aperture sonar system of the present invention includes a range curvature compensating section having a divided aperture propagation time calculation 32. The calculation 32 calculates a round-trip signal propagation time on the basis of a divided aperture for transmission and a divided aperture for reception, thereby calculating a range curvature correction time. A transmission/reception section includes a PRF (Pulse Repetition Frequency) modificator and a divided aperture switch. The PRF modificator adjusts PRF such that a ratio between the aperture length and the divided aperture length of the transducer is an integral multiple. The divided aperture switch 16 switches the outputs of elements on the transducer each being assigned to one of the divided apertures, produces a sum of the outputs of the individual element on each divided-aperture, and feeds the sum to a range compressing section. With this configuration, the system reduces range curvature compensation errors, prevents the transducer from being scaled up, and eases limitations on the number of multi-transmission/reception ascribable to a platform speed.