Research On Real-time Monitoring Data Processing Of GNSS Geological Disasters

Sudden geological disasters such as volcanoes and landslides occur abruptly and cause great harm.People are difficult to prevent and often caused very serious losses.Therefore,it is particularly important to conduct timely and accurate monitoring.This puts forward new requirements for the real-time and accuracy of GNSS deformation monitoring.Thence,in order to meet the accuracy and real-time requirements,this dissertation deeply studies the relative positioning theory of GNSS,and focuses on the principle and key technologies of GPS and BeiDou joint positioning,and applies to the algorithm of sequential adjustment of robustness in Real-time monitoring of GNSS.The main research contents and conclusions of this article are as follows:(1)Detailed introduction of GPS,GLONASS and BeiDou time system,coordinate system and signal broadcast method.For the problem of determining the stochastic model in the relative positioning of GPS and BeiDou joint,the error of the observed values of each satellite system was analyzed by the zero baseline test method.The results show that: The BDS satellite observations are basically the same as the GPS satellite residuals.The two types of observations can be treated as equal-precision observations,and the GLONASS satellite observations are appropriately weighted to participate in adjustment calculations.(2)In order to meet the real-time and accuracy of geological disaster monitoring and improve the robustness of the adjustment results,the theory of robust sequential adjustment of the parameters changes is introduced in detail,and the parameters of the sequential adjustment of the tolerance adjustment are also described.The method is applied to the real-time solution of GNSS data.This method solves the adjustment problem when the number of satellites is less than 4 in the single epoch solution and is not affected by the cycle slip.The results show that the RMS of the horizontal direction error of the monitoring point is 1-2.5cm and the RMS of the elevation direction error is between 2-3cm,and the influence of gross errors can be well avoided.(3)In order to verify the superiority of GPS & BDS combined system in the monitoring of geological disasters in complex environments,the deformation period of geological disasters was simulated using the vehicle-mounted vehicle dynamic relative positioning method,and analyzed from two aspects: the fixed rate of ambiguity and the PDOP value of satellites.The results show that GPS & BDS combined system can effectively improve the accuracy of dynamic positioning and ensure the continuity of positioning,especially for GNSS dynamic positioning in complex environments.(4)The application of the sequential differential adjustment algorithm of GPS and BeiDou combination to Xuanhang railway and earth dam deformation monitoring in the east,and compared with the results of GPS and BeiDou system,the results show that: GPS & BDS combination system combination The accuracy is better than single system in E,N,U directions.