利用多系统GNSS干涉反射测量估计长江巴东水位变化

Water level changes at Badong station of the Yangtze River from multi-GNSS interferometric reflectomery

水位信息是研究水循环、气候和生态环境变化的重要参数,近实时、高精度地监测其变化具有重要的意义.传统水位计测量成本高、范围小,且是相对水位测量.全球导航卫星系统干涉反射测量(GNSS-IR)利用岸边架设的GNSS接收机所获取的信噪比(SNR)数据估计水位变化,为水位测量提供了一种新的监测方法,具有全天候、高精度和近实时等优点.本文利用长江上游巴东多系统GNSS观测站采集30 d的GPS、BDS以及GLONASS系统SNR数据,反演了水位变化,并和水位站进行比对,结果表明GNSS-IR获得厘米级的水位反演精度,RMSE最低为6.43 cm.GPS和GLONASS系统L1频段以及BDS系统B1频段估计结果较好,GLONASS系统L2频段的反演精度低于其他频段.联合不同GNSS系统估计水位变化,提高了GNSS-IR反演水位的时间分辨率.

Water level information is an important parameter for studying changes in the water cycle,even the climate and ecological environments.It is of great significance to monitor the water level changes in near real-time and with high precision.However,traditional water level gauge is a relative water level measurement approach in a small range and has a high cost.The Global Navigation Satellite System Interferometric Reflectometry(GNSS-IR)uses the Signal-to-Noise Ratio(SNR)data from the GNSS receiver installed on the coast to estimate the water level change,which provides a new monitoring approach for water level measurement with high accuracy and near real-time.Here,30 days of GPS,BDS and GLONASS SNR data from a multi-GNSS station at Badong station in the upper reaches of the Yangtze River are used to estimate the water level changes,which are then compared with the in-suit water level station observations.The results show that GNSS-IR obtains centimeter-level water level results with the minimum RMSE of 6.43 cm.The estimation results of GPS and GLONASS system at L1 frequency and BDS system at B1 frequency are better,and the accuracy of GLONASS L2 frequency is lower than that of other frequencies.The joint multi-GNSS system improves the time resolution of GNSS-IR estimation of water level changes.