Raw SNR data for Manuscript "GPS Interferometric Reflectometry : Using a Low Cost Antenna to Measure Water Levels"

Raw GPS L1 SNR (and ancillary) data for an experiment to use a low-cost GPS antenna/receiver to measure water levels using the GNSS - Interferometric Reflectometry technique. The data were recorded at the RNLI lifeboat station in Sligo, Ireland (N 54o 18' 17.8'', W 8o 34' 5.4'' ) using a Globalsat BU353S4 USB puck that uses a SirfStar IV receiver with patch antenna (2018 data) and a Maestro A2200A SirfStar IV module (2019 data). Both systems were mounted to a radio mast at around 16m above sea level. The data are stored in daily files with the naming convention sligDDD0.YY.TNR.gz where DDD is the Day of Year and YY is the year in short format (18,19). Each file is gzipped. The files are flat text files with fixed width columns in the following order 1) PRN GPS satellite code 2) Elevation (degrees) 3) Azimuth (degrees) 4) Seconds of Day 5) change in elevation angle with time (degrees/second) : needed for reflector height change corrections 6) Blank 7) S1 SNR signal (dB-Hz) 8) Blank reserved for S2 SNR signal 9) Blank reserved for S5 SNR signal

本数据集为利用低成本GPS天线与接收机，通过GNSS干涉反射测量（GNSS Interferometric Reflectometry, GNSS-IR）技术开展水位测量实验所获取的原始GPS L1信噪比（Signal-to-Noise Ratio, SNR）及辅助数据。数据采集于爱尔兰斯莱戈市的英国皇家全国救生艇协会（Royal National Lifeboat Institution, RNLI）救生艇站，坐标为北纬54°18′17.8″、西经8°34′5.4″。2018年的采集设备为搭载SirfStar IV接收机与贴片天线的Globalsat BU353S4 USB型GPS接收机；2019年则使用Maestro A2200A SirfStar IV模块。两套系统均安装在海拔约16米的无线电桅杆上。数据以单日文件形式存储，命名格式为`sligDDD0.YY.TNR.gz`，其中DDD为年积日，YY为两位简写年份（18、19），所有文件均经过gzip压缩。文件为固定宽度列的纯文本文件，各列顺序依次为：1) GPS卫星PRN（Pseudo-Random Noise）码；2) 仰角（单位：度）；3) 方位角（单位：度）；4) 当日秒数；5) 仰角随时间的变化率（单位：度/秒，用于反射面高度校正）；6) 空白列；7) S1信噪比信号（单位：dB-Hz）；8) 预留空白列，用于存储S2信噪比信号；9) 预留空白列，用于存储S5信噪比信号