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題 名 | 單音束水深測量誤差之探討=Research on the Errors of Single Beam Echo Sounding |
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作 者 | 薛憲文; 史天元; 吳泓毅; 王韋樺; 王聖瀚; 劉黃宗隆; | 書刊名 | 海洋工程學刊 |
卷 期 | 14:2 2014.06[民103.06] |
頁 次 | 頁121-131 |
分類號 | 351.923 |
關鍵詞 | 單音束測深儀指標常數; 測深板測深檢校; 聲速剖面; 壓力式潮位計; 大氣壓修正; Index constant for single beam echo sounder; Bar check; Sound velocity profile; Pressure tide gauge; Air pressure correction; |
語 文 | 中文(Chinese) |
中文摘要 | 測量誤差的來源有:人為誤差、儀器誤差及自然誤差。而測量誤差的種類則可分為:錯誤、系統誤差及偶然誤差。由於海底之底床是不可見的,加上海底地形會隨時風、浪、流及潮汐等外力之影響而變化,因此水深測量之檢核常需要特別注意其時效性。水深測量之精度評估可以分為相對精度(或內精度)及絕對精度(或外精度),雖然相對精度之成果極佳,但仍可能存在系統誤差,而絕對精度通常需要以相同等級或更高等級的設備及測量方法施測相同水域來獲知,在測深實務上常受限於時程或經費而不易做到,所以水深測量作業程序之正確性相形重要。單音束水深測量的誤差來源包含:量測誤差、音鼓靜態吃水量誤差、音鼓動態吃水量誤差、聲速剖面誤差、船隻上下起伏量誤差、潮位誤差及各感測器之偏移量誤差等。因此在水深測量之作業時,常需要針對這些可能發生的誤差來源及測深原理,來擬定正確的作業程序、作業方法與資料處理過程。單音束測深儀是否存在指標常數,是需要時時加以探討試驗的。測深板測深檢校程序之原理雖然簡單,然而該作業仍必須要配合所使用不同的單音束測深儀,而注意其設定及作業程序之差異。雖然目前操作者會覺得聲速剖面儀及壓力式潮位儀容易上手,然而除了需要特別注意遵循標準操作程序外,仍常需要配合測深板測深檢校程序來檢核之;若狀況允許最好固定時間就將這些測深的輔助儀器送回原廠檢修為宜。由於利用測深的交錯檢核只能瞭解相對精度,加上該成果若有系統誤差,即使閱讀乙方的測量成果或報告通常也不易發現這些誤差,因此為避免失去重測或立即探討問題所在的時機,委請第三方(或丙方)來執行水深測量監驗也是另一種極佳的選擇。 |
英文摘要 | Surveying error sources include: human error, equipment error and natural error. The error types of surveying are mistake, systematic error and random error. Owing to invisability of the ocean water plus sea bottom change often caused by wind, wave, current and tide, hydrographic check survey should be done with care within reasonable time difference between two surveys. Accuracy estimation for hydrographic survey can be relatively (internal accuracy) or absolutely (external accuracy). You should always understand it may include systematic error even its relative accuracy is good. It needs to use a similar or higher accurate echo sounding system to do absolute accuracy estimation, however, it is usually hard to be done in practice. That means performing a correct Standard Operating Procedure (SOP) for hydrographic survey is very important. Error sources from single beam echo sounding includes: Measurement errors, draft error, settlemnt and squat, sound profiling error, heave error, tide error, and offset measurement errors etc. The hydrographer always needs to operate according to SOP, its theories and correct processing process. It may exist index constant of a single beam echo sounder. So, bar check is needed all the time. Its operating and parameters setting procedures are different according to echo sounders. Most of the sound velocity profiler and pressure tide gauge are easily to use, but it should be operated according to SOP. And it is needed to check the accuracy of these equipments. Sending back to above mentioned accessories manfacurer to check and calibrate every 1-2 years is a good way of making sure in its good condition. Cross check can only obtains relative accuracy, but it is not easy to find out existing errors from reading survey reports and isolate existed systematic errors. In order to avoid missing the opportunity of re-survey and investigation of possible problems, it is suggested to offer a supervised project to a third pary for quality assurance. |
本系統中英文摘要資訊取自各篇刊載內容。