| In recent years,the global navigation satellite system has been continuously developed.With the completion of the global network of BDS,the positioning accuracy has reached the centimeter or even millimeters,so that it can be better used in the field of precise measurement.This paper studies the key technology of precise measurement of Real-time kinematic(RTK)carrier phase differential settlement monitoring based on satellite navigation.In the precision measurement of RTK settlement monitoring,the determination of integer ambiguity is the key issue to realize high-precision monitoring.This paper mainly for integer ambiguity resolution in RTK technology,the design and implementation of a steel structure settlement monitoring system based on GNSS-RTK technology,and the data processing of settlement monitoring the three parts are studied in detail.Firstly,in response to the problems of the traditional SSA in searching for integer ambiguity in DGPS,such as weak global search ability and easily falling into local optimization,a hybrid strategy Sparrow Search Algorithm is proposed for integer ambiguity search.Before searching,a Circle chaotic map is introduced to initialize the population to improve the diversity of the initial population;During the search process,the particle velocity strategy of particle swarm optimization is introduced into the discoverer location update formula to improve the optimization ability of the algorithm;At the later stage of the search,a Gaussian mutation strategy is introduced to perturb the optimal sparrow position,enhancing the ability to jump out of the local optimum.The proposed algorithm is applied to nine benchmark functions with different characteristics for experiments,and the results show that the hybrid strategy sparrow search algorithm has good optimization accuracy and convergence speed.Finally,the improved algorithm is applied to the integer ambiguity search problem.The experimental results show that the improved algorithm has a better success rate compared to SSA and LAMBDA algorithms.Then,on the basis of the above,carrying out the research on the practical engineering application of RTK technology.A steel structure settlement monitoring system based on GNSS-RTK is proposed.This system is divided into a reference station and a monitoring station.The stations are transmitted wirelessly for easy installation.The settlement data collection and data transmission based on GNSSRTK technology is realized.Finally,a processing method to improve the accuracy of settlement data is proposed to address the problem of low data accuracy and inability to effectively monitor settlement when GNSS-RTK technology is applied to settlement monitoring.The experimental results show that the improved quartile distance method and Kalman filter can effectively improve the accuracy of settlement data,making the steel structure settlement monitoring system achieve millimeter level settlement monitoring accuracy.At the same time,the abnormal data warning line can also achieve effective monitoring of settlement data. |
