Signal extraction for GPS deformation monitoring in mining survey

The basic signal model of deformation monitoring with GPS was introduced and the main problems of GPS deformation monitoring in mining area were discussed. For the problem of noise signal extraction in GPS deformation monitoring, the Kalman-EMD method was proposed to obtain the effective deformation signal. The reliability and effectiveness of the methodology were tested and verified by analog signal. The results of experiment in Mongolia show that the accuracy of the proposed GPS deformation monitoring model is equivalent to that of level method.

Occurrence and Damage of Maize Gray Leaf Spot and Its GPS Monitoring

Maize gray leaf spot is a kind of leaf disease seriously threatened the production of maize,which occurs all around the world.The occurrence and damage conditions of maize gray leaf spot at home and abroad and in Yunnan Province are described,the latest research process of maize gray leaf spot are summarized,and the integrated control methods of maize gray leaf spot and its GPS monitoring are further introduced.

A new method for mining deformation monitoring with GPS-RTK

Based on ranging intersection theory, a new method which is simple and easy to operate was proposed for data collection in the mine surface deformation monitoring with GPS-RTK centering rod measurements. It can fully eliminate the inevitable shaking error and the vertical deflection, and to some extent weaken the multipath effect on the estimates of coordinates in a relatively short period of time, using high-frequency observations. The results show that three-dimensional coordinates with a height accuracy better than 1 cm, horizontal accuracy better than 2-4 cm can be achieved through only 15-30 s continuous observation by 20 Hz high-frequency and effectively improve the measurement accuracy and efficiency of RTK, fully satisfying the high-speed and high-precision data acquisition in mine surface subsidence deformation monitoring.

Engineering vibration monitoring by GPS:long duration records

Monitoring the performance of any structure requires real-time measurements of the change of position of critical points. Different techniques can be used for this purpose, each one offering advantages and disadvantages. The technique based on satellite positioning systems （GPS, GLONASS and the future GALILEO） seems to be very promising at least for long period structures. The GPS in particular provides sampling rates that are able to track dynamic displacements with high accuracy. Its service ability is independent of atmospheric conditions, temperature variations and visibility of the monitored object. This paper investigates the reliability and accuracy of the measurements of dual frequency GPS receivers. A linear electromagnetic motor moves an object along a given direction. The changes of position are compared witb their estimates as recorded by a GPS receiver, whose antenna is located on the reference object. The comparison is based on sufficiently long records.

A New GPS System for Continuous Deformation Monitoring

This paper presents a multi-antenna GPS based system developed for local continuous deformation monitoring. Due to a large number of points that needs to be monitored, the standard approaches of using permanent GPS receiver arrays will cause high cost. It eventually becomes the limiting factor for large-scale use of GPS in these application areas. Multi-antenna GPS system allows a number of GPS antennas to be linked to one GPS receiver by a specially designed electronic component, i. e. the so-called GPS multi-antenna switch (GMS), The receiver takes data sequentially from each of the antennas attached to the receiver. A distinctive advantage of the approach is that one GPS receiver can be used to monitor more than one point. The cost per monitored point (i. e. the expenses of hardware) is therefore significantly reduced.

Dynamic Deformation Monitoring of Lotsane Bridge Using Global Positioning Systems (GPS) and Linear Variable Differential Transducers (LVDT)

The measurements and analysis of deformation of engineering structures such as dams, bridges and high-rise buildings are important tasks for civil engineers. It is evident that, all civil engineering structures are susceptible for deterioration over a period of time. Bridges in particular, deteriorate due to loading conditions, environmental changes, earth movement, material used during construction, age and corrosion of steel. Continuous monitoring of such structure is the most important aspect as it provides quantitative information, assesses the state of the structure, detects unsafe positions and proposes early safety measures to be taken before it can threaten the safety of vehicles, goods and human life. Despite government’s efforts to construct roads and highways, bridge deformation monitoring has not been given priority in most of African countries and ultimately causes some bridges to collapse unexpectedly. The purpose of this research is to integrate Global Positioning System (GPS) and Linear Variable Differential Transducers (LVDT) to monitor deformation of a bridge. The horizontal positions of reference and monitoring points were determined using Global Positioning System (GPS) while the vertical deflections, accelerations and strain were determined using Linear Variable Differential Transducers (LVDT). The maximum displacements obtained between zero and first epochs in x, y and z components were 0.798 m, at point LT08, 0.865 m at point BR13, and 0.56 m at point LT02 respectively. The maximum deflections for LVDT 1, 2 and 3 are 28.563 mm, 31.883 mm and 40.926 mm respectively. Finally, the correlation coefficient for the observations was 0.679 with standard deviations of 0.0168 and 0.0254 in x and y respectively. Our results identified some slight displacements in horizontal components at the bridge.

Mining subsidence monitoring using the method of combining InSAR and GPS technology

Attempted to conduct a dynamic monitoring research on coal mining subsidence in western mining areas by using the method of combining D-InSAR and GPS technology. The observation points were installed on the main section and the three-dimensional coordinates of the points were measured by using the method of dynamic differential GPS. Meanwhile, the radar images of this subsidence area were processed by using the method of interferometry with daris software, and the interferogram of the subsidence area was obtained. Through this study, the GPS monitoring data and the InSAR deformation data were integrated and the dynamic subsidence contours of the experimental area were obtained. GPS/InSAR fusion technology provides a new technological means for large-scale dynamic monitoring of coal mining subsidence in western mountainous mining areas and shows good application prospects in coal mining subsidence monitoring and disaster warning.

Theory and Practice of the SSDM for GPS Deformation Monitoring

Global Positioning System technique is widely used to monitor the deformations of all kinds of buildings and constructions. According to the characteristics of the high precise GPS deformation monitoring, the theory and practice of the SSDM （Similar Single-Difference Methodology） for GPS deformation monitoring are introduced synthetically from the background, the essential mathematic model,the error sources and control measures, the monitoring schemes and the software development. Some arguments are also given in the form of reference literatures. Based on the first period observation results of the GPS monitor network, SSDM solves the monitoring points＇ deformation values at a single epoch from carder phases directly, without needing to solve baseline vectors and network adjustment. The SSDM avoids the troublesome problem of detecting and repairing cycle slips, and can be used in static and dynamic deformation monitoring. In the SSDM, the unknown parameters have no relation to the numbers of satellites. If the number of synchronous satellites between stations is not less than two, the monitoring point＇s deformation information can be solved easily.

GPS monitoring and analysis of ground movement and deformation induced by transition from open-pit to underground mining

To trace the potential hazards of open-pit slope in Longshou mine,global positioning system（GPS） is applied to monitoring ground movement and deformation induced by transition from open-pit to underground mining.Through long-term monitoring from 2003 to 2008,huge amounts of data were acquired.Monitoring results show that large-scale ground movement and deformation have occurred in mining area,and the movement area is ellipse-shaped.The displacement boundary of settlement trough is 2.0 km long along the exploratory line,and 1.5 km long along the strike of ore body.GPS monitoring results basically agree with the practical deformation state of open-pit slope.It is indicated that the long-term GPS monitoring is an effective way to understand the mechanism of ground movement and deformation in mine area. 更多

Coal mining GPS subsidence monitoring technology and its application

We proved theoretically that geodetic height, measured with Global Positioning System （GPS）, can he applied directly to monitor coal mine subsidence. Based on a Support Vector Machine （SVM） model, we built a regional geoid model with a Gaussian Radial Basis Function （RBF） and the technical scheme for GPS coal mine subsidence monitoring is presented to provide subsidence information for updating the regional Digital Elevation Model （DEM）. The theory proposed was applied to monitor mining subsi- dence in an Inner Mongolia coal mine in China. The scheme established an accurate GPS reference net- work and a comprehensive leveling conjunction provided the normal height of all GPS control points. According to the case study, the SVM model to establish geoid-model is better than a polynomial fit or a Genetic Algorithm based Back Propagation （GA-BP）neural network. GPS-RTK measurements of coal mine subsidence information can be quickly acquired for updating the DEM.

GPS Dynamic Monitoring Experiment and Result Analysis of Long-Span Cable-Stayed Bridge

For the sake of timely appraising the working con di tion of the bridge, measuring the dynamic characteristics of the bridge structur e is very important and necessary. A GPS dynamic monitoring test was carried out in the Wuhan Baishazhou Bridge, which is one of the longest span cable-stayed bridges having been built in China. This paper introduces the experimental imple menting scheme and data processing method. The vibration characteristics of the middle span of cable-stayed bridge are availably obtained by use of the spectra l analytic approach. The measuring results are very identical to the theoretical designed values. The research demonstrates that, with GPS receiver of the high sampling rate and suitable data processing method, the vibration characteristics of the bridge structure can be determined with high accuracy.

Monitoring crustal movements in northern Tianshan Mountain based on GPS technology

Monitoring results for the period 2009-2014 by ten standard GPS stations allowed to determine the crustal movements of seismically active region in south-eastern Kazakhstan. Maps of movement velocity were made in geocentric coordinate system and in reference system of the Eurasian continent. GPS points displacements reflect the features of modern deformation processes that are notable in the high seismic activity region. The structure of the velocity field divergence qualitatively confirms major deformation in the sublatitudinal direction which is parallel to the main ridge of the northern Tianshan Mountain. The epicenters of earthquakes are in agreement with the border areas of compression -tension, as well as the allocated areas of multidirectional rotary motion. The conclusion is that GPS monitoring of the movements of the Earth＇s crust can be used to evaluate the territory＇s stress-strain state for the purpose of seismic zoning and seismic risk assessment.

Experimental research on daily deformation monitoring of steel box girder bridge based on BDS/GPS

In order to investigate the feasibility of BDS/GPS in the deformation monitoring of long-span bridges,analysis and research on aspects like number of visible satellites,PDOP value and monitoring precision are carried out. To analyze daily deformation characteristics of steel box girder bridge,observation data for 48 consecutive hours is computed by self-programmed software. Experiment results show that the monitoring-points on the bridge demonstrate obvious periodicity and recoverability in vertical and horizontal directions,meanwhile,changes in the elevation direction are relatively stable. The deformation-monitoring results of BDS/GPS combination system and GPS single system show good consistency. However,in a complex environment of the bridge,especially under the condition that satellite signals are severely affected,the advantages of BDS/GPS combination over GPS single system are more obvious.

Rigid Bridges Health Dynamic Monitoring Using 100 Hz GPS Single-Frequency and Accelerometers

This article presents the modal frequency recordings of a rigid bridge, monitored by the GPS receivers (Global Positioning System) with a data recording rate of 100 Hz and accelerometers. The GPS data processing was performed through the double-difference phase, using the adjusted interferometry technique (i.e. phase residue method—PRM&reg). In the method, the double-difference phase of the carrier L1 is realized by using two satellites only, one was positioned at the zenith of the structure and the other satellite was positioned near the horizon. The results of the parametric adjustment of the PRM observations were finalized through software Interferometry, mathematical algorithm were applied and compared with the accelerometer. The comparison served to validate the use of GPS as a fast and reliable instrument for the preliminary monitoring of the dynamic behavior of the bridge, road artworks which are common in several countries, especially in the Brazilian road network. The data time series from the GPS and accelerometers were processed using the Wavelet. The detection of frequencies means that the combination of 100 Hz GPS receivers and the PRM allows detecting vibrations up to 5 mm. It presented significant results which were never obtained by the Fourier Transform.

GPS AUTOMATIC MONITORING SYSTEM FOR OUTSIDE DEFORMATION OF GEHEYAN DAM ON THE QINGJIANG RIVER

In this paper,the background of developing GPS Automatic Monitoring System for outside deformation of Geheyan Dam is described concisely.The framework,precision and features of the system are stated in detail.Finally,the prospective application of the system is introduced.

Monitoring of ground subsidence movements over territory of mines being flooded in Budyonnovsky and Proletarsky districts in Donetsk city with help of GPS-technology

This paper considers the processes of activation in ground subsidence movements in flooding mine workings of mines being liquidated in two districts in Donetsk city on the area of more than 60km^2. A concept is given to build up control network of geomechanical monitoring in conditions of existing old mining operations at shallow depths (down to 100m), strong damages of objects of urban building. Given are GPS network structure, layouts for location of basic and local profile lines, special control stations for monitoring ground subsidence movements over the territory of mines being flooded. Results of the series of observations made are discussed and their accuracy is analyzed.

A new approach of single epoch GPS posi- tioning for landslide monitoring

When the deformation of landslide becomes larger, the conventional static GPS surveying cannot satisfy the real-time requirement in landslide monitoring. In this paper we present a new method for single epoch GPS posi- tioning combining with the accuracy of approximate coordinates of monitored station in landslide monitoring. This algorithm does not consider troublesome cycle-slip problem of carrier phase, and integer ambiguities can be solved at a single epoch, so the centimeter level accurate coordinates can be calculated instantaneously. By means of fil- tering or smoothing, this method can be extended to detect millimeter level deformation and velocity. In order to test the new method, low-cost single frequency receivers have been used in a real landslide, which happened in Jiangxi Province, China.

Analysis on the noises from continuously monitoring GPS sites

In this paper, we analyze the time series of site coordinates of 27 continuously monitoring GPS sites covered by the Crustal Movement Observation Network of China over the whole country. The data are obtained in the period from the beginning of the observation to the November of 2005. On the basis of data processing, we analyze the power spectrum density of coordinate component noise at each site and calculate the spectral indexes manifesting the noise property of each component. The spectral indexes indicate that for most sites, the noise of time series of each coordinate component can be addressed by the model of white noise ＋ flicker noise; and for a small amount of sites, it can be described by the model of white noise ＋ flicker noise ＋ random walk noise. We also quantitatively estimate each noise component in the model by using the criterion of maximum likelihood estimation. The result shows that the white noise in the time series of GPS site coordinates does not constitute the main part of noise. Therefore, the error estimation of site movement parameters is usually too small, or too optimistic if we consider the white noise only. Correspondingly, if this factor is not fully considered in explaining these movement parameters, it might mislead the readers.

Arctic glacier movement monitoring with GPS method on 2005

During the 2005 Arctic Yellow River Station expedition, the research on monitoring the movement and mass balance of two glaciers around Ny-Alesund, Austrelovenbreen and Pedersenbreen, which were selected in the 2004 Yellow River Station expedition were conducted. This paper analyzes the feasibility and advantage in using GPS method to monitor the Arctic glaciers＇movement, estimates the precision of first time measured GPS data and discusses the relevant problems in surveying on the Arctic Glaciers with GPS.

Establishment and Data Processing of High-Precision City Subsidence Monitoring Network by GPS Surveying Instead of Leveling

The feasibility of moni-toring the change of city settlementusing GPS surveying instead of level-ing is studied. A fiducial network anda monitoring network are establishedin Ningbo city. Two periods of GPSobservation are completed. Somemeasures are taken during the obser-vation in order to ensure to obtain thehigh-precise height component. TheSaastamoinen model is adopted in thedata processing of the dry componentpart of the tropospheric delay. Thewet component change of the tropo-spheric delay is estimated by stochasticprocesses model. When Bernese soft-ware is used to process the data, themillimeter level precision of heightmeasuring is achieved.