多音束測深系統(Multi-Beam Echo Sounder)是同時以多個窄波束聲波向海底發射以測量海底地形。各音束投射在海底的位置稱之為足印(footprint)。足印位置的推算有賴於精確掌握船隻位置、姿態、音鼓架設相對位置。有了上述資訊，經過數個坐標轉換後，才能獲得每一個足印的精確位置。其中音鼓主軸架設的方向和船隻主軸的方向略有差異，會有橫搖角(rolling)、縱搖角(pitching)、航偏角(yawing)等的常偏差量。本研究中嘗試用未校正前之原始數據產生海底的近似平面，藉由不同測線所得之近似平面間的差異，修正這三個架設角的偏差量。我們選取三鄰近測線A、B及C，測線選擇的條件為：A與B平行且反向，C與A、B垂直。A、B兩測線所獲得之近似平面，若有橫搖角偏差存在時，兩平面交界處會有V型或倒V型的情形。修正橫搖角會使這個V型漸漸展平；當兩平面平行時，即完成橫搖角的修正。A、B兩測線經過海底斜坡的環境，如一測線順坡，另一測線逆向爬坡時，若有縱搖角偏差量存在時，兩平面會平行但存在高度差距。修正縱搖角會使兩平面相互接近或遠離，當兩平面重合時，即完成縱搖角的偏差修正。經過前面兩個角度的修正後，若兩正交的測線經過一個有坡度的海底環境時，求得的兩近似平面間仍會有一夾角存在。此時改變航偏角將可消弭這個誤差。當兩平面重合時，即完成航偏角之修正。本文用模擬的海底地形及實測資料驗證這個方法的可行性。並將所得結果與商用軟體(HYSWEEP)校正所得之結果互相比較。

Multibeam sonar systems are much more efficient than the convectional single-beam echo sounders for seafloor-mapping in hydrographic surveying. On the other hand, the operation of multibeam sonar systems needs to integrate more auxiliary sensor units. Because the world coordinates of each footprint is calculated based on the geometry of the sonar head relative to the GPS of the ship. Therefore, the resulting survey quality highly depends on the accuracy of the estimated mounting configuration of the sonar head, and other sensor units. Basically, the configuration parameters include the three Euler's angles, three linear translations and the asynchronous latency of signals between the transducer and other sensors. These parameters can not be measured directly. They can only be estimated from the post-process of the bathymetry data called patch test. Generally, the patch test requires the survey ship to follow several designated paths which are parallel, reciprocal or perpendicular to each other. Furthermore, the choice of seabed slope is also an important factor for the quality of the result. The contour plots of the seabed for the different paths are used to estimate the mounting configuration of the sonar head.

In this work, we propose best-fitting a small flat patch to represent the seabed right beneath a segment of the path. A pair of patches from the two adjacent segments of reciprocal or perpendicular paths are selected for comparison. The difference between the two patches gives us an idea how the mounting parameters, i.e. the rolling, pitching and yawing angles, might be. If the parameters are accurately estimated, the two patches should be co-plane. We design several semi-positive definite functions and feed back control algorithms to steer the mounting angles to search for the solutions. One more advantage of this approach is that the variation of each mounting angles as the survey undergoes can be monitored. We test this idea with simulated seabed data, and field data as well. The result is within 1\% difference compared with respect to the angles calibrated by commercial software, such as Hypack.

摘要
Abstract
目錄 …………………………………………………………………i
圖目錄 ………………………………………………………………iii
表目錄 ………………………………………………………………vii
第一章 緒論 1
1.1 前言 ……………………………………………………………1
1.2 文獻回顧 ………………………………………………………2
1.3 研究方法 ………………………………………………………4
第二章 校正原理 5
2.1 前言 ……………………………………………………………5
2.1.2 相關文獻 ……………………………………………………5
2.1.2 本研究 ………………………………………………………8
2.2 橫搖角偏差之修正 ……………………………………………9
2.3 縱搖角偏差之修正 ……………………………………………10
2.4 航偏角偏差之修正 ……………………………………………11
2.5 坐標轉換說明 …………………………………………………13
第三章 模擬 15
3.1 地形設計 ………………………………………………………16
3.2 不規則平面 ……………………………………………………17
第四章 實測資料處理 19
4.1 實驗區簡介 ……………………………………………………19
4.1.1 A區 …………………………………………………………19
4.2.2 B區 …………………………………………………………22
4.2 偏差角度估算 …………………………………………………23
4.2.1 A區 …………………………………………………………24
4.2.2 B區 …………………………………………………………30
4.3 大型目標物重建 ………………………………………………33
4.4 分析與討論 ……………………………………………………41
第五章 結語 42
5.1 結論 ……………………………………………………………42
5.2 建議 ……………………………………………………………43
5.3 未來工作 ………………………………………………………44
參考書目 ……………………………………………………………45
附錄A　檔案格式 47
A.1 DGPS原始資料格式 ……………………………………………47
A.2 船隻動態收集儀原始資料格式 ………………………………48
A.3 多音束原始資料格式 …………………………………………49
A.4 航向儀原始資料格式 …………………………………………50
A.5 資料分布情形 …………………………………………………51
附錄B　修正程式 52
B.1 β修正程式 ……………………………………………………52
B.2 α修正程式 ……………………………………………………55
B.3 γ修正程式 ……………………………………………………55

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