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An electronically focused multiple beam side scan sonar
Phased arrays have been in use since World War II but their commercial application has been constrained by the bulk and cost of the beam forming system. High resolution side scan sonar systems have many operational parameters that may only be extended with the aid of phased arrays, the resolution an...
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| Format: | Thesis |
| Language: | English |
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Department of Electrical Engineering
2017
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| _version_ | 1867613150730256385 |
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| access_status_str | Open Access |
| author | Fox, Peter |
| author2 | Denbigh, P N |
| author_browse | Denbigh, P N Fox, Peter |
| author_facet | Denbigh, P N Fox, Peter |
| author_sort | Fox, Peter |
| collection | Thesis |
| description | Phased arrays have been in use since World War II but their commercial application has been constrained by the bulk and cost of the beam forming system. High resolution side scan sonar systems have many operational parameters that may only be extended with the aid of phased arrays, the resolution and the imaging rate being the most important. This thesis describes a microprocessor controlled dynamically focused side scan sonar where high resolution and high image acquisition rates are achieved. Dynamic focusing prevents the depth of field limitations of fixed focus arrays by updating the array phases at regular intervals so as to create a focal point which recedes from the array in synchronism with the returning echoes from the transmitted pulse. A high image acquisition rate is achieved through the simultaneous formation of multiple beams. Using a microprocessor as a low-cost controller demands rapidly executable software and a little specialized hardware. Programmable quadrature phase shifters give phase and amplitude control. A beam forming board combines the phase shifted signals into a beam and samples it. A 'time domain multiplexed' transmitter solves the problem of efficient insonification of swaths. The system timing is complex; while image samples are captured data is formatted and presented for recording on a chart recorder. This occurs in real-time, while the focus of each of the multiple beams is changed almost every two meters. Tank tests of the completed system provide confirmation of the resolution predicted with theory and computer simulation. Sea trials confirm that resolution close to that predicted may be obtained under operational circumstances. The results obtained fully justify the assertion that low cost microprocessor controlled dynamically focused multiple beam phased arrays are both an attainable and an attractive solution to the problems faced by the designer of high resolution side scan sonar systems. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/26521 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:31:34.243Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| publisher | Department of Electrical Engineering |
| publisherStr | Department of Electrical Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/26521 An electronically focused multiple beam side scan sonar Fox, Peter Denbigh, P N Electrical Engineering Phased arrays have been in use since World War II but their commercial application has been constrained by the bulk and cost of the beam forming system. High resolution side scan sonar systems have many operational parameters that may only be extended with the aid of phased arrays, the resolution and the imaging rate being the most important. This thesis describes a microprocessor controlled dynamically focused side scan sonar where high resolution and high image acquisition rates are achieved. Dynamic focusing prevents the depth of field limitations of fixed focus arrays by updating the array phases at regular intervals so as to create a focal point which recedes from the array in synchronism with the returning echoes from the transmitted pulse. A high image acquisition rate is achieved through the simultaneous formation of multiple beams. Using a microprocessor as a low-cost controller demands rapidly executable software and a little specialized hardware. Programmable quadrature phase shifters give phase and amplitude control. A beam forming board combines the phase shifted signals into a beam and samples it. A 'time domain multiplexed' transmitter solves the problem of efficient insonification of swaths. The system timing is complex; while image samples are captured data is formatted and presented for recording on a chart recorder. This occurs in real-time, while the focus of each of the multiple beams is changed almost every two meters. Tank tests of the completed system provide confirmation of the resolution predicted with theory and computer simulation. Sea trials confirm that resolution close to that predicted may be obtained under operational circumstances. The results obtained fully justify the assertion that low cost microprocessor controlled dynamically focused multiple beam phased arrays are both an attainable and an attractive solution to the problems faced by the designer of high resolution side scan sonar systems. 2017-12-11T10:14:41Z 2017-12-11T10:14:41Z 1985 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/26521 eng application/pdf Department of Electrical Engineering Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Electrical Engineering Fox, Peter An electronically focused multiple beam side scan sonar |
| thesis_degree_str | Doctoral |
| title | An electronically focused multiple beam side scan sonar |
| title_full | An electronically focused multiple beam side scan sonar |
| title_fullStr | An electronically focused multiple beam side scan sonar |
| title_full_unstemmed | An electronically focused multiple beam side scan sonar |
| title_short | An electronically focused multiple beam side scan sonar |
| title_sort | electronically focused multiple beam side scan sonar |
| topic | Electrical Engineering |
| url | http://hdl.handle.net/11427/26521 |
| work_keys_str_mv | AT foxpeter anelectronicallyfocusedmultiplebeamsidescansonar AT foxpeter electronicallyfocusedmultiplebeamsidescansonar |