GPS bridge deformation monitoring technology research?

What are the GPS technology bridge monitoring measurement methods? How to carry out the test? Please see the article edited by Zhongda Consulting.

1 deformation monitoring

The so-called deformation monitoring refers to the use of relevant measuring instruments and methods of mine rock and surface movement, dams, slopes, surface settlement, earth deformation, etc. in the form of data or images recorded as a basic information to analyze its safety, for the prediction and forecasting of deformation development trend and speed to make a scientific and reasonable explanation. According to the scope of deformation monitoring can be divided into three categories: engineering construction and local deformation research, regional deformation research, global deformation research.

But no matter which type of deformation monitoring, its detection principle and method are similar, the monitoring content can basically be divided into the following categories: First, ground settlement, in order to accurately make accurate prediction of ground settlement and timely protective measures, the need for ground deformation to do cyclical observation, and to effectively grasp the basic laws of the ground uplift and settlement; Second, the geotechnical buildings, this type of deformation monitoring Secondly, geotechnical buildings, this kind of deformation monitoring is mainly based on different structures to make different deformation monitoring content; thirdly, industrial and civil buildings, this kind of deformation monitoring mainly includes vertical displacement, horizontal displacement, dynamic deformation monitoring, building itself tilt crack monitoring and uniform subsidence of building foundation. The main significance of deformation monitoring is to study the law of deformation, do deformation analysis and prediction, verify the structural design, feedback construction quality and assess the safety status of the building.

At present, the deformation monitoring methods and technologies mainly include four categories: First, ground photogrammetry technology, such technology has its limitations, due to the reduced resolution of the photographic equipment, resulting in the monitoring of the scope of the small, low-precision, but with the flourishing development of digital photography technology, coupled with the gradual maturation of real-time photography technology, ground photogrammetry technology has ushered in a new opportunity for development; Second, specialized measurement methods, such as tilt measurement, collimation measurement, and the use of the ground photogrammetry technology to monitor the deformation of the building foundation. Measurement methods, such as tilt measurement, collimation measurement, static level measurement and other non-civil engineering deformation monitoring within the scope of traditional measurement methods.

Third is geodetic measurement, which is the most commonly used traditional methods, mainly through leveling, edge measurement, angle measurement and other related technologies to complete the determination of deformation, geodetic accuracy is high, and has formed a more perfect theory and method, but its own also has many defects, such as low measurement efficiency, low degree of mechanization, modernization, in large-scale engineering measurements, the workload is large, difficult; fourth is the new deformation monitoring methods, such as inclination measurement, collimation measurement, static level measurement, and other non-civil engineering deformation monitoring traditional measurement category. Difficulty; Fourth, the deformation monitoring of new technologies, the promotion and application of new technologies has been the direct impetus to improve the level of monitoring, in recent years, such as computerized tomography, laser scanning, InSAR technology, etc. have become the deformation monitoring of emerging technologies, although some of the technology is not mature enough, but it does greatly improve the monitoring of the accuracy and reduces the difficulty of monitoring.

2 bridge deformation monitoring

The health monitoring of bridge has become an important method to prevent the instability of bridge structure, especially the deformation monitoring during the operation of the bridge, which is of great significance. The main content of bridge monitoring includes the following aspects:

(1) bridge tower deformation monitoring, which the main observations include the overall inclination observation of the tower column body, the observation of the expansion and contraction of the inclined tower column body, the observation of the disturbance of the tower column body, the observation of the horizontal displacement of the top of the tower column, and so on.

(2) bridge plane displacement monitoring, vehicle load, wind load and other external factors will cause the displacement of the bridge foundation, so the monitoring of the bridge deck displacement is perpendicular to the direction of the bridge axis of the horizontal displacement.

(3) bridge pier deformation monitoring, the main content includes pier vertical displacement monitoring and pier horizontal displacement monitoring.

(4) bridge deflection monitoring, the bridge deck in the external load will occur under the action of the bridge directly affects the safety of the bridge deck and the bridge life along the bridge axis direction of the vertical displacement, that is, deflection.

Bridge deflection monitoring methods are more, in the deflection observation there are photogrammetric methods, total station observation hair, leveling methods, overhanging method, special deflectometer observation method and GPS measurement method, etc.; Horizontal displacement monitoring methods, including the wire method, angular method, baseline method, rendezvous method and GPS measurement method; Vertical displacement monitoring methods, including precision leveling method, static leveling method, Vertical displacement monitoring methods include precision leveling, static leveling, triangular elevation measurement and GPS measurement.

From the above introduction, it can be seen that GPS measurement can be carried out in all aspects of bridge deformation monitoring, high synchronization, high precision, convenient and reliable and so on a little bit decided that GPS technology in the bridge deformation monitoring in the development of a bright future.

3 Based on the bridge monitoring GPS deformation monitoring technology

GPS is known as GlobalPositioningSystem, that is, the global positioning system, the system contains user acceptance equipment, ground monitoring part and space part of the three major components. The user accepts the equipment that is GPS signal receiver, through some series of signal capture, data acquisition, data processing steps to calculate the equipment is located in the geographic location of the time, speed, altitude and latitude and longitude and other information; Ground control system is composed of monitoring station, ground antennae, the main control station; The space part of the 3 standby satellites and 21 working satellites, uniformly distributed in the 6 orbital plane, from the surface of the earth 20,200,000 kilometers above the ground.

The principle of GPS positioning measurement is based on the data code (D code), ranging code (C/A code, P code) and carrier signal under the GPS satellite emission calculation. The basic principle of pseudo-ranging measurement principle is based on the space backward rendezvous, assuming that at a certain moment t, a certain point P to the three satellites of the spatial distance were (), the satellite's spatial coordinates for (√(〖__^〗^〖__^〗

The formula: for the receiver clock difference correction; for the satellite clock difference correction for the troposphere delay correction for the ionosphere delay correction.

Carrier phase measurement principle is based on the GPS satellite's L-band carrier and carrier of the two high-frequency signals and positioning, assuming that the satellite at the moment of the phase of the ___D_Dd ______, the amount of phase change that occurs, the carrier phase measurement principle of the basic expression for:

Equation: for the integer week, ___D_Dd ____

There are two main measurement methods of GPS technology in bridge deformation monitoring, one is the decision positioning method, and the other is the relative positioning method. the GPS static relative positioning method is a linear combination of phase observation and carrier phase observation techniques, assuming that the two receivers and, respectively, they are in, at the moment, respectively, the satellite m, n for synchronized observation, and so the following phase angles are obtained:

GPSPTK mode is based on carrier phase, GPS receiver is set up in the reference station for receiving satellite signals, and at the same time transferring the observation value and coordinates to the mobile station, which is set up in the measurement point for receiving the information of the reference station and satellite signals, and at the same time, using the differential technology to process the information, so as to realize the real-time positioning, and give the coordinates of the point to be measured.

The above GPS bridge deformation monitoring technology research collected and organized by Zhongda Consulting

More about the engineering/service/procurement category of the tender writing production, to enhance the winning rate, you can click on the bottom of the official website customer service for free consultation:/#/?source=bdzd