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The development of correlation log
A measure of ship speed is needed for dead reckoning navigation, docking, and as an input to satellite navigation systems. Ship speed is also used as an input to fire control systems on Naval vessels. The need for an accurate speed measuring device, that measures ship speed relative to the sea bed i...
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| Format: | Thesis |
| Language: | English |
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Department of Electrical Engineering
2017
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| _version_ | 1867613143759323136 |
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| access_status_str | Open Access |
| author | Horwitz, Adrian Miles |
| author2 | Denbigh, P N |
| author_browse | Denbigh, P N Horwitz, Adrian Miles |
| author_facet | Denbigh, P N Horwitz, Adrian Miles |
| author_sort | Horwitz, Adrian Miles |
| collection | Thesis |
| description | A measure of ship speed is needed for dead reckoning navigation, docking, and as an input to satellite navigation systems. Ship speed is also used as an input to fire control systems on Naval vessels. The need for an accurate speed measuring device, that measures ship speed relative to the sea bed is thus apparent. All non acoustic logs measure ship speed relative to the water, and absolute ship speed can only be estimated if a knowledge of water currents is available. An acoustic log that provides an absolute measure of ship speed at limited operating depths is the Doppler log. For deep water the Doppler log measures speed relative to the water and it is thus affected by currents. A new development in acoustic logs is the correlation log. The correlation log can measure absolute speed at much greater depths than can the Doppler log. This is because it utilises a wide beam pointing vertically at the sea bed. The.wide beam permits a low operating frequency to be used which implies low attenuation. The high backscattering strength at normal angles of incidence combined with the low attenuation, means that relative to the Doppler log, the correlation log can measure absolute speed at much greater depths. The correlation log consists of a transmitter, which utilises tone burst transmission, and two or more receivers in line with the direction of motion. The signals received by two transducers will be similar except for a time shift 'T', which is given by the equation T = d/2V, where V is the speed and d the transducer separation. A device based on these principles has been built and tested. Results have shown that the system concepts are viable and will lead to an absolute speed measuring device that can operate at great depth. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/26076 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:31:28.055Z |
| 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:11427/26076 The development of correlation log Horwitz, Adrian Miles Denbigh, P N Electrical Engineering, Electronic and Electrotechnical Engineering A measure of ship speed is needed for dead reckoning navigation, docking, and as an input to satellite navigation systems. Ship speed is also used as an input to fire control systems on Naval vessels. The need for an accurate speed measuring device, that measures ship speed relative to the sea bed is thus apparent. All non acoustic logs measure ship speed relative to the water, and absolute ship speed can only be estimated if a knowledge of water currents is available. An acoustic log that provides an absolute measure of ship speed at limited operating depths is the Doppler log. For deep water the Doppler log measures speed relative to the water and it is thus affected by currents. A new development in acoustic logs is the correlation log. The correlation log can measure absolute speed at much greater depths than can the Doppler log. This is because it utilises a wide beam pointing vertically at the sea bed. The.wide beam permits a low operating frequency to be used which implies low attenuation. The high backscattering strength at normal angles of incidence combined with the low attenuation, means that relative to the Doppler log, the correlation log can measure absolute speed at much greater depths. The correlation log consists of a transmitter, which utilises tone burst transmission, and two or more receivers in line with the direction of motion. The signals received by two transducers will be similar except for a time shift 'T', which is given by the equation T = d/2V, where V is the speed and d the transducer separation. A device based on these principles has been built and tested. Results have shown that the system concepts are viable and will lead to an absolute speed measuring device that can operate at great depth. 2017-11-08T12:34:02Z 2017-11-08T12:34:02Z 1985 2017-03-06T10:29:23Z Master Thesis Masters MSc (Eng) http://hdl.handle.net/11427/26076 eng application/pdf Department of Electrical Engineering Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Electrical Engineering, Electronic and Electrotechnical Engineering Horwitz, Adrian Miles The development of correlation log |
| thesis_degree_str | Master's |
| title | The development of correlation log |
| title_full | The development of correlation log |
| title_fullStr | The development of correlation log |
| title_full_unstemmed | The development of correlation log |
| title_short | The development of correlation log |
| title_sort | development of correlation log |
| topic | Electrical Engineering, Electronic and Electrotechnical Engineering |
| url | http://hdl.handle.net/11427/26076 |
| work_keys_str_mv | AT horwitzadrianmiles thedevelopmentofcorrelationlog AT horwitzadrianmiles developmentofcorrelationlog |