全球導航衛星系統反射訊號反演海水位數據處理：以烈嶼LIEY站為例

On the Data Processing of Sea Level Height using GNSS-IR:A Case Study at LIEY Station

「全球導航衛星系統反射訊號干涉技術」（GNSS interferometric reflectometry, GNSS-IR）可以用於獲得反射面至接收機天線相位中心之垂直距離。當反射面為感潮水面時，可用於海水潮位觀測，亦即達成潮位站之功能。地基式單一右旋圓極化（Right-Hand Circular Polarization, RHCP）天線的GNSS觀測方式具備良好的便利性與普及性，相對於雙天線（右旋圓極化及左旋圓極化）的系統，較能容忍反射面的粗糙度。本文使用Prof. Kristine M. Larson所提供之「gnssrefl」程式（Larson, 2024），以設置於烈嶼南山頭之LIEY站，記述操作之流程與初步成果。
本程式為開源軟體，為使用者便利，Prof. Larson提供Docker版本，方便於微軟Windows環境中安裝。在一般性的處理中，已可以產出良好成果。

The ''Global Navigation Satellite System Interferometric Reflectometry'' (GNSS-IR) technique can be used to determine the vertical distance between a reflective surface and the phase center of the receiver antenna. If the reflective surface is a tide-sensitive water surface, this method can be applied for sea-level observations, effectively functioning as a tide gauge. Using ground-based GNSS observations with a single Right-Hand Circular Polarization (RHCP) antenna offers significant convenience and accessibility. Compared to dual-antenna (RHCP and LHCP) systems, it also exhibits greater tolerance to surface roughness.
This study utilizes the ''gnssrefl'' program provided by Prof. Kristine M. Larson, applying it to the LIEY station located at Nanshan, Lieyu. The operational workflow and preliminary results are documented.
The program is open-source, and for user convenience, Prof. Larson offers a Docker version, simplifying installation on Microsoft Windows systems. This software (open source) has already demonstrated the capability to produce reliable results in general processing scenarios.