GNSS RTK技术下海洋平台桩腿动态变形监测及数据处理

海洋平台及其桩腿在长期使用中存在着波浪、海流、风荷载等环境激励作用下的动态响应。本文以海星达H32全能型GNSS RTK双频接收机为试验仪器,采用GPS+GLONASS+BDS三星系组合系统对位于渤海海域的埕岛油田某平台桩腿进行动态变形监测。结合Ensemble Empirical Mode Decomposition(EEMD)和Butterworth滤波方法的降噪特性,提出一种适用于海洋平台工作环境的新型混合滤波方法 MDB,并用Matlab软件编制的程序对GNSS RTK监测数据进行分析,得到桩腿测点的实时振动位移曲线。结果表明:GNSS RTK结合MDB滤波技术用于海洋平台桩腿动态变形监测是可行的;MDB滤波器能有效去除海洋平台振动信息的随机噪声和多路径误差;从去除多路径误差和随机噪声之后的海洋平台桩腿测点位移云图,可以非常清楚地看出桩腿在环境激励作用下水平方向产生的可逆位移轨迹,这对海洋平台结构健康监测、诊断和评估具有重要意义。

Dynamic deformation monitoring and the data processing of offshore platform piles based on GNSS RTK technology

Dynamic responses of offshore platforms and their piles under environmental excitations such as waves, currents and wind loads exist in long-term service. In this paper, the dynamic deformation monitoring of the pile of a platform in Chengdao oil field of Bohai Bay is carried out by using the H32 omnipotent GNSS RTK dual frequency receiver as the test instrument with the GPS+GLONASS+BDS three-star system. Combined with the noise reduction characteristics of Ensemble Empirical Mode Decomposition (EEMD) and Butterworth filtering methods, a hybrid filtering method, MDB, which is suitable for the working environment of offshore platform, is proposed, and the real-time curve of the measuring point of the pile is obtained by using the program compiled by Matlab software to analyze the monitoring data of the GNSS. Results show that GNSS RTK combined with MDB filtering technology is feasible to monitor the dynamic deformation of offshore platform leg, and MDB filter can effectively remove the random noise and multipath error of vibration information of offshore platforms. And from the displacement nephogram of offshore platform legs after removing multi-path errors and random noises, the reversible displacement trajectory of the legs in the horizontal direction can be clearly seen, which is of great significance to the health monitoring, diagnosis and evaluation of offshore platform structures.