Research On GNSS Dynamic And Static Combined Measurement Technology In The Bridge Deformation Monitoring

With the development of GNSS,the capabilities of software and hardware systems are continuously improved,and GNSS is applied more and more widely in the deformation monitoring of super large bridges.The GNSS real-time kinematic positioning measurement method can measure the position of the rover receiver in real time,but only one epoch satellite observation data is used for the baseline solution,the measurement accuracy can only reach the centimeter level.Real-time kinematic method can not fully meet the needs of high-precision deformation monitoring of bridges.The GNSS static relative positioning data processing method performs the post-baseline solution by multi-epoch satellite observation data,and constructs the baseline vector into the baseline vector network to adjust the position of the receivers,although the measurement accuracy can reach millimeter level,but this method requires a large number of epoch observation data for post-processing,and the data processing frequency is limited,and the deformation monitoring result of the bridge feature points can not be obtained in real time.Based on the advantages and disadvantages of the above two methods,this paper proposes a new static post-processing method for GNSS dynamic measurement of bridge deformation monitoring,and relies on the Chongqing Sunxi River Bridge health monitoring project to research GNSS dynamic and static combined measurement technology in bridge deformation monitoring.The main research contents of this paper include the following:Firstly,according to the principle of GNSS positioning measurement,the static post-processing method of GNSS dynamic measurement for bridge deformation monitoring is proposed.The realization process of this method is discussed in detail.The advantages and calculation results' accuracy and reliability of the method are analyzed by comparing with the traditional real-time kinematic positioning method.Secondly,combined with the operation monitoring project of the Sunxi River Bridge,the GNSS deformation monitoring system of the Sunxi River Bridge was designed.The system design,system integration,coordinate system design and data processing methods were introduced in detail.Thirdly,the accuracy difference between the Beidou navigation and positioning system and the US global positioning system in the bridge deformation monitoring work is studied,and the feasibility of the Beidou navigation and positioning system in the bridge deformation monitoring is discussed.Fourthly,according to the GNSS deformation monitoring data of the Sunxi River Bridge,combined with the temperature and wind sensor data,the relationship between the deformation monitoring point of the Sunxi River Bridge and the temperature and wind is studied in depth.And visualization of Sunxi River Bridge dynamic deformation are realized by the least squares curve fitting method.Fifthly,the principle of spectrum analysis method is studied.The GNSS monitoring results are compared with the monitoring results of the Sunxi River Bridge acceleration sensor to verify the availability of GNSS in bridge vibration frequency monitoring.