| Land subsidence is the ground elevation loss under the comprehensive effect of natural factors and human factors. Excessive settlement, particularly uneven settlement, can make the surface building tilt, cracking so that cannot be used properly. In recent years, subsidence disaster has grown more serious. All levels of government and industry have attached great importance to it. The State Council twice issued circulars on further strengthening the safe production in enterprises, safety first, prevention first, comprehensive treatment. Therefore it has practical significance to study settlement observation technology. Existing settlement observation technology is mostly to use measuring instruments such as precise level, high precision alloy steel level ruler, total station, displacement sensor. There are many shortcomings:the operation period is long, artificial measure is time-consuming and laborious, the automation degree is not high. Thus this subject develops a new settlement observation automatic system based on the Beidou II high-precision positioning technology, wireless data link technology and intelligent information processing technology. Responsible for the server software design, this paper mainly research on following aspects:(1) Based on C/S architecture, we design an automatic web server software for surface subsidence observation. First of all, the software can get the settlement observation data from Internet network in real time transmitted from multiple field observation equipment; Then calculating the precise location of observation point based on high-precision positioning algorithm, and the precision can reach millimeter; Finally using the powerful database to store calculating results in real time, meanwhile graphically display many index of settlement observation.(2) We design a layered-belief data filtering algorithm combining with the least square method to guarantee the accuracy of the positioning results. Insufficient satellite observation data will result in positioning calculation results error, in this paper the layered-belief data filtering algorithm, based on the epoch number of received satellite observation data every day, gives the positioning results different confidence levels, further based on confidence levels uses filtering method to determine the final positioning result each day, and it effectively ensures the positioning accuracy.(3) We design a functional software combining industry standard and the customization demand of application unit. For the standardization demand of settlement field, we design many index of settlement observation including settlement, settlement rate, period settlement and period settlement rate, etc. This software can automatically produce the settlement curve and data tables, can graphically display the regional subsidence state, and have functions of database query and analysis, etc. The software can also be applied to other observations fields of earth deformation monitoring.Through this software, users can master the security situation of subsidence area of concern. This software can help users to checkup security risks and can provide users decision support, and to reduce the harm brought by settlement. It is full-time, high-precision, automatic, high real-time. It can effectively solve the shortcomings of traditional method, such as time-consuming, laborious, low degree of automation, and it has important guiding significance and reference value for the settlement observation. |
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