| With the increasing demand for high-precision positioning in social life,the application fields of high-precision positioning technology and its products are becoming more and more extensive,especially in the fields of buildings and slope deformation monitoring.Traditional deformation monitoring methods mainly rely on precise measuring instruments,which are often restricted by geographical,human and environmental factors,which makes it difficult to meet today's large-scale deformation monitoring requirements.The Global Navigation Satellite System(GNSS)is one of the most advanced positioning methods,and its precision measurement technology can be used in the field of deformation monitoring.However,in a city with high-rise buildings or a tortuous grand canyon,the positioning ability of the GNSS will be greatly reduced as the satellite signal is blocked,the birth of pseudolite(PL)technology can effectively make up for the deficiencies.The positioning system composed of pseudolites can be combined with GNSS system or a separate network to achieve deformation monitoring.The wide application of mobile communication represented by4G/5G provides new ideas and innovative possibilities for the network design of the deformation monitoring system.The distributed wireless data transmission network constructed by the 4G/5G technology can collect the data collected by the receiver in real time.The observation data is transmitted back to the data monitoring center for centralized processing.This dissertation aims at pseudolite technology and its application in the field of deformation monitoring,based on the distributed wireless data transmission network of4G/5G technology,a high-precision deformation monitoring system is designed by using pseudolite technology,and several key technologies in the system are analyzed and researched.The main research contents include the following aspects:(1)Design of high-precision deformation monitoring system scheme based on distributed wireless network.Through the analysis of the domestic and foreign pseudolite technology and deformation monitoring application and development status,according to the characteristics of distributed application of deformation monitoring,a high-precision deformation monitoring system that can realize remote automatic monitoring is designed by using pseudolite positioning technology and 4G/5G wireless transmission technology.(2)Aiming at the clock synchronization problem in pseudolite deformation monitoring system,a high-precision clock difference algorithm between pseudolite stations based on carrier phase is implemented.Based on the structure of the traditional pseudolite system,a masterslave pseudolite network structure is adopted,and the receiver of clock difference monitoring station with dual antenna is introduced.The simulation results show that the clock synchronization accuracy of the algorithm reaches the order of nanoseconds,and the correctness of the algorithm is verified through experiments.(3)In view of the problem of cycle slip and repair in pseudolite deformation monitoring system based on carrier phase technology,through the analysis of the existing single-frequency cycle slip detection and repair methods,a new method of cycle slip detection and repair based on outlier test is improved.Simulation results show that this method can effectively solve the problem of single frequency receiver cycle slip.(4)According to the different application environments and monitoring application requirements of the pseudolite deformation monitoring system,the carrier phase absolute positioning and relative positioning are adopted respectively,and the corresponding positioning algorithm is completed.Experimental results show that the positioning accuracy of the two positioning methods is similar in the horizontal direction,and the deformation monitoring effect is equivalent;relative positioning in the vertical direction can provide better positioning accuracy and better deformation monitoring effect. |
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