US4460987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable focus sonar with curved array
Assignee: United States Department of the Navy
•
Filing: 1982-04-22
•
Granted: 1984-07-17
•
Expires: 2002-04-22
Abstract
Abstract Variable focus in a sonar system of the time delay beamformer type using aonvexly curved electroacoustic array is achieved by changing the operating frequency.
Inventors
- 👤 Robert H. Stokes
- 👤 James F. Lynch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:53
CPC Classifications
G; G01; G01S; G01S15/00; G01S15/02; G01S15/06; G01S15/08; G01S15/10; G01S15/102; G01S15/107; G10; G10K; G10K11/00; G10K11/18; G10K11/26; G10K11/34; G10K11/341; G10K11/343
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
100 words
A variable focus sonar system comprising: a convexly curved array of electroacoustic transducer elements; time delay beamforming means, connected to said array, for effecting predetermined delays in individual electrical signals having a selected operating frequency f o within a range of operating frequencies and corresponding to predetermined ones of said transducer elements so that said array is characterized by a corresponding focal length; selectively variable frequency means, coupled to said time delay beamforming means, and operative to change said selected operating frequency to a different operating frequency f o whereby said array is characterized by a corresponding different focal length.
Claim 2
Dependent Claim
100 words
A variable focus sonar system comprising: a convexly curved array of electroacoustic transducer elements; time delay beamforming means, connected to said array, for effecting predetermined delays in individual electrical signals having a selected operating frequency f o within a range of operating frequencies and corresponding to predetermined ones of said transducer elements so that said array is characterized by a corresponding focal length; selectively variable frequency means, coupled to said time delay beamforming means, and operative to change said selected operating frequency to a different operating frequency f o whereby said array is characterized by a corresponding different focal length.
Claim 3
Dependent Claim
21 words
A variable focus sonar system as defined in claim 1, and wherein: said variable frequency means comprises a variable oscillator means.
Claim 4
Dependent Claim
36 words
A variable focus sonar system as defined in claim 2, and wherein: said convexly curved array is a circular array, and said predetermined ones of said transducer elements comprise an arcuate segment of said circular array.
Claim 5
Dependent Claim
39 words
A variable focus sonar system as defined in claim 3, and wherein: said beamforming means forms part of a transceiver, and said array is adapted to both project and receive acoustic signals of said selected and different operating frequencies.
Claim 6
Dependent Claim
73 words
A variable focus sonar system as defined in claim 3, and wherein: the relationship between the refocused range ρ o ' and the original range ρ o from the array to a point in a refocused zone of focus due to change from said selected operating frequency f o to said different operating frequency f o ' can be expressed substantially as ##EQU2## where R.sub.τ is the radius of curvature of said array.
References Cited (Backward Citations)
US2875355A
Cited
US3086195A
Cited
US3090030A
Cited
US4187556A
Cited
US3474402A
Cited
US3585579A
Cited
US3914731A
Cited
US4152678A
Cited
US4271490A
Cited
US4241611A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-17 | 1988-01-16 | 1988-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-17 | 1992-01-16 | 1992-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-17 | 1996-01-16 | 1996-07-17 | $7700.00 | Window Closed / Lapsed |