Study On The Application Of GPS Coordinate Time Series In Hazard Analysis Of Houses

Housing safety has always been a hot issue that people pay attention to and discuss.Accurate analysis results of housing risk are of great significance to the security of people's lives and property.In some projects,the result of how the housing is dangerous should be got during long-term observation,including tilt state and settlement of the housing.If using levelling instrument,total station instrument or other traditional instruments,it will produce large workload.The process of observation is also susceptible to environmental factors,and unable to realize the real-time dynamic monitoring of the housing.The GPS deformation monitoring technology and its real-time coordinate time series will not be bound by internal structure of the house.In addition,this method can observe multiple monitoring points at the same time,with all-weather,high degree of automation,low cost for long-term monitoring.It is suitable for long-term monitoring of deformation characteristics such as tilt state and settlement change.However,when analyzes the risk of housing by GPS method,the following two factors influence the accuracy of analysis:(1)The GPS coordinates of time series usually contains noise,the noise and dynamic change characteristics of building mix together.As a result,it is hard for us to extract the dynamic change law of the house,brought adverse effects to the data analysis;(2)Due to receiver failures,power supply problems or satellite anomalies,the time series of GPS coordinates are often missing to varying degrees.The missing sequence fragments destroy the integrity and continuity of the dynamic change law of the house,resulting in inaccurate deformation characteristics,deformation law and the judgment of trend.Therefore,this paper studies the impact of the quantitative analysis of housing hazards on the noise and sequence absence contained in the GPS coordinate time series.The specific work contents are as follows:(1)According to the plane regression model of housing tilting state and the identification method of dangerous houses,this paper proposes to obtain the index of housing tilting rate and housing settlement by GPS monitoring sequence,and applies it to the quantitative analysis of housing hazard.(2)Aiming at the noise contained in the GPS coordinate time series,an improved wavelet threshold method and EMD method are introduced to reduce the noise of the time series,so as to obtain a smoother,less noisy and more accurate coordinate time series.(3)In the case of missing GPS coordinate time series,a GPS coordinate time series completion model based on chaos theory and LSTM is proposed to improve the completion accuracy of missing sequences.(4)Based on the actual deformation monitoring results of the building,this paper discusses the influence of improved threshold wavelet noise reduction method,chaos theory and LSTM completion method on the accuracy error of quantitative analysis of housing hazard.That is,after denoising or completion of the GPS coordinate time series by using the method in this paper,the error of tilt rate and settlement change of the house can be reduced compared with the real deformation degree of the house.Among them,the minimum error of the tilt rate of the house in three months is about 0.113 mm,and the error of settlement is 0.387 mm,both of which can meet the requirements of quantitative analysis of the risk of the house for data accuracy.