Research And Application Of GPS Building Deformation Monitoring

GPS has become one of the main methods for real-time deformation monitoring of buildings because of its advantages.Because GPS measurement values are affected by a variety of errors,the accuracy of GPS single point positioning has difficult to meet the monitoring accuracy requirements specified in the national building measurement standard specification;GPS deformation monitoring data usually contains noise,gross error and real deformation,so it is necessary to process the monitoring data to remove the noise and gross error,and retain the real displacement.In order to solve the above problems,this paper focuses on the following work:(1)The research of carrier phase differential GPS mainly includes the analysis of various errors of GPS measurements,the derivation of single and double difference equations,and the solution of the whole cycle ambiguity of double difference.(2)The post-processing method of GPS deformation monitoring data is studied,and a fusion algorithm combining wavelet transform and adaptive robust Kalman filter is proposed.(3)Construct the composite denoising evaluation index,test the GPS monitoring data with different wavelet functions,different wavelet decomposition levels and different adaptive robust filtering process noise covariance,and obtain the best denoising effect guided by the composite evaluation index.(4)The baseline three-dimensional coordinates of GPS real-time deformation monitoring data of a high building are calculated,and the processing effects of wavelet transform,adaptive robust Kalman filter and fusion algorithm on baseline noise and abnormal data are tested respectively.(5)Analyze the periodicity of satellite distribution and baseline coordinates,and use this periodicity combined with the multi day displacement curve of the monitoring point to analyze the deformation of the monitoring point.On the basis of the above work,this paper has achieved the following results:using the GPS baseline solution program to get the baseline three-dimensional coordinates of a monitoring point,the coordinate accuracy in three directions has reached the millimeter level;the fusion algorithm can effectively remove the noise and gross errors in the baseline,at the same time,it can quickly adjust the actual displacement,successfully extract the deformation information and further improve the accuracy The monitoring accuracy of GPS is improved,and the baseline displacement curve of 5 consecutive days is combined to analyze,and it is found that the monitoring point has a certain degree of displacement in the elevation direction.