Study On Methods Of Monitoring Deformations Of Offshore Oil Platform Based On GNSS And Static Leveling

Offshore oil drilling platform is an important infrastructure for exploration and development of offshore oil and gas resources.The harsh marine environment,means that the structural health monitoring of offshore oil platforms is important for operation and maintenance of platforms.In this paper,the structural health monitoring method of offshore oil platform based on GNSS-RTK positioning technology and static leveling technology is studied,and the dynamic deformation monitoring test analysis of the actual offshore oil platform project is carried out by using these two technologies.The main research contents and research results are as follows:According to the working principle of GNSS,this paper analyzes the influencing factors of GNSS positioning quality,discusses the positioning accuracy and reliability of GPS + BDS integrated system,and reveals that the introduction of BDS system into GPS positioning is helpful to improve the number of visible satellites,the effective number of positioning data and the reliability ratio of calculation data,and reduce the PDOP value and RMS of spatial position accuracy attenuation factor,so as to improve the accuracy and reliability of system positioning.In this paper,several kinds of GNSS-RTK positioning methods on the sea are tested.Through the comparison of RTK conventional difference,Beacon difference and MSAS difference,the results show that the positioning accuracy of RTK conventional difference is in the order of centimeters,while the positioning accuracy of Beacon differential and MSAS station differential is in the order of decimeters.And MSAS satellite station differential positioning has one characteristic: its positioning error has continuous drift phenomenon.It means that,in a short positioning time domain,the difference of MSAS satellite station has a high internal coincidence positioning accuracy.In view of the application of GNSS technology in deformation monitoring of offshore oil platform,the surrounding environment of the platform is seawater with strong reflection of satellite signals and various metal facilities and electrical equipment on the platform with strong interference to satellite signals.According to the principle of multipath effect error of GNSS-RTK technology,this paper discusses the regularity of multipath effect error,selects various kinds of ground environment to test multipath effect error,and analyzes the test results,revealing the difference of multipath effect error between different ground environment.In order to reduce the multipath effect error of GNSS-RTK technology,a hybrid filtering method based on Chebyshev and EEMD analysis is proposed for joint denoising,and this method is applied to process the GNSS-RTK monitoring test data of offshore oil platform.The experimental results show that this method can effectively eliminate the multipath effect error in the monitoring data.A set of remote automatic monitoring system of offshore oil platform settlement based on the principle of static leveling is designed.And it is applied to the settlement monitoring test of offshore oil platform.Through the processing and analysis of the test data,the results show that the system is running well.It can continuously and automatically monitor the settlement of offshore oil platform at millimeter level,and realize remote transmission and early warning.GNSS-RTK technology is applied to three-dimensional deformation(horizontal displacement and settlement)monitoring of offshore oil platform.Through 24-hour continuous monitoring test and data processing analysis,the results show that GNSS-RTK is not suitable for the monitoring of centimeter scale or smaller settlement of offshore oil platform at present.By filtering and denoising the monitoring data,GNSS-RTK technology is expected to meet the requirements of10 km offshore Requirements for centimeter level displacement monitoring of offshore oil platforms.