使用海床聲學特徵估測機器魚橫移運動之模擬研究

Simulation Study on Sway Estimation of Robotic Fish Using Acoustic Features of Seafloor

李宗益(Tsung-Yi Lee)

指導教授 ： 郭振華

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201904310

摘要

本研究以提升聲納微導航技術之參考地圖特徵為主軸，選用擺尾型機械魚為載體來執行模擬，並搭配具高解析度之合成孔徑聲納。因機械魚的擺動運動及非完美剛性結構的特點，使聲納陣列產生橫移(sway)誤差，讓輸入回聲訊號會隨之抖動，導致合成參考地圖失真的問題。故在本研究導入演算法來估測並修正此誤差現象，提升參考地圖特徵在微導航技術上之精準度，利於未來微導航技術運用。
本文中以簡介合成孔徑聲納為基礎，進一步比較合成孔徑及真實孔徑對影像的解析能力，和相關影響影像解析之參數，並介紹合成孔徑常用的ω-k、CS、ACS演算法。利用合成孔徑聲納特性，選用冗餘相位偏移中心演算法估測橫移誤差，使合成孔徑聲納探測過程，雖受橫移誤差影響，但仍具有足夠估測能力，得以校正參考地圖，達成輔助微導航系統之目的。
接續以多目標物為模擬場景，討論載具目標物於不同條件下，對於橫移誤差的估測能力。最後將針對此模擬研究應用在機械魚橫移運動估測上，並於各式模擬的比較中做出結論。

關鍵字

微導航系統 ； 機械魚 ； 合成孔徑聲納 ； ACS演算法 ； RPC演算法

並列摘要

This purpose of this study is to improve the performance of the micro-navigation system for describing the seabed image. The high resolution sonar image create from information to the synthetic aperture sonar (SAS). When the SAS system placed on the hard structure robotic fish, it will receive not only the shake signal but the sway error, forming the blurred image. In order to correct the sway error of the SAS system, this thesis will discuss the method of the estimation of the sway error for improving accuracy of the micro-navigation system.
This thesis will introduce the fundamental of the SAS, compare the difference of synthetic aperture and real aperture to discuss the resolution and interferences of the sonar image. Continuously, bring in the commonly used sonar imaging algorithm, as the ω-k, CS and ACS algorithm, in this research.
As the characteristic of the SAS system, it can apply the redundancy phase center (RPC) algorithm to estimate the phase error from the raw data from, and prove that it can get the enough compensate to correct the sonar image though the raw data including the sway error. Discussing the multiple cases of the targets can get the more clearly discussion of the sway error.

並列關鍵字

micro-navigation system ； robotic fish ； synthetic aperture sonar ； ACS algorithm ； RPC algorithm

參考文獻

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