Research On Reconfigurable Antenna Array Based On MEMS Technology

In recent years,building collapse accidents have emerged one after another.From 2000 to 2019,83 large-scale bridge collapse accidents occurred in China,which seriously threatened the safety of life and property of the broad masses of people and caused serious national economic losses.Considering the safety hazards in the design,construction and use of construction facilities such as Bridges,DAMS and tall buildings,deformation monitoring will become an indispensable technical means.GPS high precision positioning technology has been widely used in building deformation monitoring in recent years.In GPS short baseline double-difference positioning,ionospheric delay,tropospheric delay,satellite orbit error,receiver clock error and satellite clock error can be reduced or eliminated by carrier phase difference technology,but the multi-path interference at both ends of the baseline is not correlated,so it cannot be eliminated by carrier phase difference technology.Therefore,how to reduce and eliminate the multi-path error has become an urgent problem to be solved in deformation monitoring using GPS high-precision positioning technology.The existing solutions are mainly divided into three categories:one is to choose the appropriate base station construction address;Second,the design of excellent performance of the antenna and receiver;Third,we study more robust filters and algorithms.But these schemes have some problems:first,the hardware equipment is expensive,the universality is poor;Second,the end effect is serious in signal processing.Third,it is impossible to extract the high frequency multipath effectively.In order to solve these problems,this paper proposes a technical solution based on GPS high-precision positioning technology to eliminate multi-path errors.The program mainly contains three research contents.One is the pre-processing technology for observation noise,and a smoothing algorithm based on two-dimensional moving weighted average is proposed.The second is the full-band multipath error extraction technology.The wavelet packet threshold denoising algorithm based on the optimal decomposition layer is proposed.As a correction technique for the position of the monitoring point,a periodic position correction algorithm based on GPS multipath is proposed.The algorithms used in these key technologies together form the WP-TD algorithm model.The algorithm model mainly solves two problems,one is to effectively avoid the end effect,and the other is to achieve multi-path error elimination of the full frequency band.Through simulation and actual measurement.It is verified that when wp-td algorithm model is applied to GPS deformation monitoring,it can effectively suppress the end effect and eliminate the multi-path error in the whole frequency band.According to the quantitative analysis,the correlation between the coordinate residual sequences for three consecutive days after filtering by wp-td algorithm is 3.02%and 1.78%higher than that of WT algorithm and Vondrak algorithm,respectively.The positioning accuracy of the adjacent days after the position correction is improved by 57.47%,65.98%and 71.61%,respectively,through the multi-path error sequence of the reference days extracted by WT algorithm,Vondrak algorithm and wp-td algorithm.It is further verified that the proposed wp-td algorithm model can more effectively extract the multi-path error model and improve the accuracy of GPS deformation monitoring.