採用多衛星跨軌干涉合成孔徑雷達偵測內波

Abstract

內波易對水下行動產生威脅，但由於其在水面上的足跡易被風浪掩埋，即時偵測很困難。本論文使用多衛星跨軌干涉合成孔徑雷達成像(multi-satellite cross-track interferometric synthetic aperture radar) 技術，獲取內波在水面上的足跡。多組衛星以不同方向、海拔飛行，將獲取的海面高度影像作平均，以消除周遭風浪的影響，但水平方向的解析度因此變差。本論文參照三起內波事件進行模擬，輔以適當參數與運作情境，可在風速每秒六公尺內達到水平方向解析度 14 公尺，海面高度誤差則在公分等級。

Internal waves, which can wreak havoc on underwater activities, are difficult to detect because their signatures on the sea surface are easily obscured by wind waves. In this work, a cross-track interferometric synthetic aperture radar (XTI-SAR) imaging technique based on multiple satellite-pairs is proposed to detect the surface signatures of internal wave, with higher height accuracy and finer horizontal resolution that can be achieved by using conventional satellite pair. By superposing the XTI-SAR images acquired from multiple satellite pairs, random features of wind waves are filtered out to reveal the surface signatures of internal wave, without compromising the horizontal resolution. Three internal-wave events are simulated to demonstrate the efficacy of the proposed approach, with height accuracy of centimeters and spatial resolution of 14 m, under wind speed of U₁₀ ≦ 6 m/s.