逐历元GNSS-R测高单差和双差算法

GNSS-R测高是一种高效监测水面高度及其变化的新技术。与传统水面测量技术,如验潮站、卫星测高等相比,其主要优点包括可实现更高时空分辨率的观测、测高结果不受板块垂直运动的影响等。本文提出了一种基于单差观测值组合的cGNSS-R逐历元测高算法,可提高水面高度测量的时空分辨率,并给出了基于双差观测值逐历元cGNSS-R测高算法。利用武汉东湖清河桥上cGNSS-R试验中GPS反射信号观测数据,给出了高精度高时空分辨率的湖面到反射天线相位中心垂直距离,验证了本文算法的准确性,精度可达±2~±4 cm。与水面高实际观测比较结果表明,cGNSS-R单差、双差算法可有效削弱钟差以及电离层和对流层误差对反演水面高度的影响。

Improved Water Level Retrieval from Epoch-by-Epoch Single and Double Difference GNSS-R Algorithms

GNSS-R is a new technology for monitoring the water level with high efficiency.Compared with conventional water level measurement technique,such as satellite altimetry and tide gauges,GNSS-R can observe more reflected points with high temporal and spatial resolution and unaffected by the influence of the plate vertical motion.This paper presented an improved cGNSS-R altimetry algorithm based on single difference to derive the reflector heights epoch-by-epoch,which can enhance the temporal and spatial resolution of surface height measurements, furthermore, the other algorithm based on the double differenced carrier phase measurements was also presented in this paper.By using the observed data of cGNSS-R altimetry experiment conducted on Qinghe bridge of East Lake,Wuhan,the reflector heights between the reflected antenna and the lake surface were given to prove the above mentioned algorithms, and the precision were ±2~±4 cm.The results show that the proposed algorithms based on single and double difference which are used for water level retrieval can sufficiently decrease the influences due to clock error,ionospheric and tropospheric error.