Consolidating the Precision of Interferometric GNSS-R Ocean Altimetry Using Airborne Experimental Data
Consolidating the Precision of Interferometric GNSS-R Ocean Altimetry Using Airborne Experimental Data
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DOI：
10.1109/tgrs.2013.2286257
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发表时间：
2014-08-01
影响因子：
8.2
通讯作者：
D'Addio, Salvatore
中科院分区：
文献类型：
--
作者：
Cardellach, Estel;Rius, Antonio;D'Addio, Salvatore
本文对利用全球导航卫星系统（GNSS）反射信号（GNSS-R）进行高度测量的精度进行了修正。特别是，我们研究了两种不同的GNSS-R技术的性能，在这里被称为清洁副本和干涉方法。前者自1990年代末以来一直用于GNSS-R活动，而后者仅于2010年在静态条件下和河口沃茨从一座18米高的桥梁上测试过一次。2011年，我们在波罗的海3公里高度进行了一次空中实验，以测试动态和粗糙条件下的干涉概念。该运动还飞行了一个干净的复制品GNSS-R仪器，目的是比较两种方法。我们详细分析了数据集，以提取和验证这两种技术中存在的噪声模型。在预测噪声模型并与飞机数据进行验证之后，我们使用它们来获得高度测量的精度并将性能分析外推到星载场景。主要结论是，建议的噪声模型与实测数据相符，全球导航卫星系统R干涉测量技术的精度至少比使用公开的全球定位系统代码的干净复制品的技术高两倍。这表示沿磁道分辨率至少精细四倍。使用近地轨道器近底点干涉式全球导航卫星系统-R观测，65公里沿轨平均应可达到22厘米的精度。
This paper revises the precision of altimetric measurements made with signals of the Global Navigation Satellite Systems (GNSS) reflected (GNSS-R) off the sea surface. In particular, we investigate the performance of two different GNSS-R techniques, referred to here as the clean-replica and interferometric approaches. The former has been used in GNSS-R campaigns since the late 1990s, while the latter has only been tested once, in 2010, from an 18-m-high bridge in static conditions and estuary waters. In 2011, we conducted an airborne experiment over the Baltic Sea at 3-km altitude to test the interferometric concept in dynamic and rougher conditions. The campaign also flew a clean-replica GNSS-R instrument with the purpose of comparing both approaches. We have analyzed with detail the data sets to extract and validate models of the noise present in both techniques. After predicting the noise models and verifying these with aircraft data, we used them to obtain the precision of altimetric measurements and to extrapolate the performance analysis to spaceborne scenarios. The main conclusions are that the suggested noise model agrees with measured data and that the GNSS-R interferometric technique is at least two times better in precision than a technique based on using a clean replica of the publicly available GPS code. This represents a factor of at least four times finer along-track resolution. A precision of 22 cm in 65-km along-track averaging should be achievable using near-nadir interferometric GNSS-R observations from a low earth orbiter.