Estimation and mapping of water erosion and soil loss:Application of Gavrilovic erosion potential model(EPM)using GIS and remote sensing in the Assif el mal Watershed,Western high Atlas

Water erosion is a serious problem that leads to soil degradation,loss,and the destruction of structures.Assessing the risk of erosion and determining the affected areas has become crucial in order to understand the main factors influencing its evolution and to minimize its impacts.This study focuses on evaluating the risk of erosion in the Assif el mal watershed,which is located in the High Atlas Mountains.The Erosion Potential Model(EPM)is used to estimate soil losses depending on various parameters such as lithology,hydrology,topography,and morphometry.Geographic information systems and remote sensing techniques are employed to map areas with high erosive potential and their relationship with the distribution of factors involved.Different digital elevation models are also used in this study to highlight the impact of data quality on the accuracy of the results.The findings reveal that approximately 59%of the total area in the Assif el mal basin has low to very low potential for soil losses,while 22%is moderately affected and 19.9%is at high to very high risk.It is therefore crucial to implement soil conservation measures to mitigate and prevent erosion risks.

Effect of digital elevation models on monitoring slope displacements in open-pit mine by differential interferometry synthetic aperture radar

Displacement monitoring in open-pit mines is one of the important tasks for safe management of mining processes.Differential interferometric synthetic aperture radar(DInSAR),mounted on an artificial satellite,has the potential to be a cost-effective method for monitoring surface displacements over extensive areas,such as open-pit mines.DInSAR requires the ground surface elevation data in the process of its analysis as a digital elevation model(DEM).However,since the topography of the ground surface in open-pit mines changes largely due to excavations,measurement errors can occur due to insufficient information on the elevation of mining areas.In this paper,effect of different elevation models on the accuracy of the displacement monitoring results by DInSAR is investigated at a limestone quarry.In addition,validity of the DInSAR results using an appropriate DEM is examined by comparing them with the results obtained by global positioning system(GPS)monitoring conducted for three years at the same limestone quarry.It is found that the uncertainty of DEMs induces large errors in the displacement monitoring results if the baseline length of the satellites between the master and the slave data is longer than a few hundred meters.Comparing the monitoring results of DInSAR and GPS,the root mean square error(RMSE)of the discrepancy between the two sets of results is less than 10 mm if an appropriate DEM,considering the excavation processes,is used.It is proven that DInSAR can be applied for monitoring the displacements of mine slopes with centimeter-level accuracy.

Remote sensing and geographic information systems techniques in studies on treeline ecotone dynamics

We performed a meta-analysis on over 100 studies applying remote sensing(RS)and geographic information systems(GIS)to understand treeline dynamics.A literature search was performed in multiple online databases,including Web of Knowledge(Thomson Reuters),Scopus(Elsevier),BASE(Bielefeld Academic Search Engine),CAB Direct,and Google Scholar using treeline-related queries.We found that RS and GIS use has steadily increased in treeline studies since 2000.Spatialresolution RS and satellite imaging techniques varied from low-resolution MODIS,moderate-resolution Landsat,to high-resolution WorldView and aerial orthophotos.Most papers published in the 1990s used low to moderate resolution sensors such as Landsat Multispectral Scanner and Thematic Mapper,or SPOT PAN(Panchromatic)and MX(Multispectral)RS images.Subsequently,we observed a rise in high-resolution satellite sensors such as ALOS,GeoEye,IKONOS,and WorldView for mapping current and potential treelines.Furthermore,we noticed a shift in emphasis of treeline studies over time:earlier reports focused on mapping treeline positions,whereas RS and GIS are now used to determine the factors that control treeline variation.

Geometrical feature analysis and disaster assessment of the Xinmo landslide based on remote sensing data

At 5:39 am on June 24, 2017, a landslide occurred in the village of Xinmo in Maoxian County, Aba Tibet and Qiang Autonomous Prefecture(Sichuan Province, Southwest China). On June 25, aerial images were acquired from an unmanned aerial vehicle(UAV), and a digital elevation model(DEM) was processed. Landslide geometrical features were then analyzed. These are the front and rear edge elevation, accumulation area and horizontal sliding distance. Then, the volume and the spatial distribution of the thickness of the deposit were calculated from the difference between the DEM available before the landslide, and the UAV-derived DEM collected after the landslide. Also, the disaster was assessed using high-resolution satellite images acquired before the landslide. These include Quick Bird, Pleiades-1 and GF-2 images with spatial resolutions of 0.65 m, 0.70 m, and 0.80 m, respectively, and the aerial images acquired from the UAV after the landslide with a spatial resolution of 0.1 m. According to the analysis, the area of the landslide was 1.62 km2, and the volume of the landslide was 7.70 ± 1.46 million m3. The average thickness of the landslide accumulation was approximately 8 m. The landslide destroyed a total of 103 buildings. The area of destroyed farmlands was 2.53 ha, and the orchard area was reduced by 28.67 ha. A 2-km section of Songpinggou River was blocked and a 2.1-km section of township road No. 104 was buried. Constrained by the terrain conditions, densely populated and more economically developed areas in the upper reaches of the Minjiang River basin are mainly located in the bottom of the valleys. This is a dangerous area regarding landslide, debris flow and flash flood events Therefore, in mountainous, high-risk disaster areas, it is important to carefully select residential sites to avoid a large number of casualties.

The Role of Remote Sensing and GIS for Locating Suitable Mangrove Plantation Sites along the Southern Saudi Arabian Red Sea Coast

This paper investigated a methodology for locating suitable sites for establishing mangrove plantations along the south Saudi Arabian Red Sea coast based on Geological characteristics, geomorphology and discharge of drainage effluents as primary sitting criteria. Remote sensing Satellite imagery and digital elevation models were interpreted to determine most of the parameters, the rest were measured in field. In the study, it was found that some healthy mangrove stands now exist along the Red Sea coast near the city of Jizan although many stands have been destroyed in recent years due to rapid development, infilling and over-grazing and use of the mangroves as fuel. Remote sensing satellite imagery was used to map exiting Mangrove stands of different densities along the study area. The study determined that mangrove stands are primarily concentrated in the southern part of the study area and that they are sparsely found northward. Interpretation of A Landsat Thematic Mapper panchromatic band image and DEM showing that red sea coast along the study area are mainly covered by fans of ten drainage basins where the Flood potentiality of these basins was determined. The study was able to determine that three areas, which have a moderate to low flash flood potential, have the necessary environmental elements necessary to support mangroves. One, in particular, would be the best site to establish a mangrove plantation project.

Determination of Potential Runoff Coefficient Using GIS and Remote Sensing

Flash floods in arid environments are a major hazard feature to human and to the infrastructure. Shortage of accurate environmental data is main reason for inaccurate prediction of flash flooding characteristics. The curve number (CN) is a hydrologic number used to describe the storm water runoff potential for drainage area. This study introduces an approach to determine runoff coefficient in Jeddah, Saudi Arabia using remote sensing and GIS. Remote sensing and geographic information system techniques were used to obtain and prepare input data for hydrologic model. The land cover map was derived using maximum likelihood classification of a SPOT image. The soil properties (texture and permeability) were derived using the soil maps published my ministry of water and agriculture in Saudi Arabia. These soil parameters were used to classify the soil map into hydrological soil groups (HSG). Using the derived information within the hydrological modelling system, the runoff depth was predicted for an assumed severe storm scenario. The advantages of the proposed approach are simplicity, less input data, one software used for all steps, and its ability to be applied for any site. The results show that the runoff depth is directly proportional to runoff coefficient and the total volume of runoff is more than 136 million cubic meters for a rainfall of 103.6 mm.

Remote Sensing Multitemporal Data for Geomorphological Analysis of the Murghab Alluvial Fan in Turkmenistan

Archaeological studies are ever more landscape-oriented, in order to study archaeological evidences in relation with their territorial contexts. In such a framework, reconstruction and understanding of ancient landscapes assume a crucial role for archaeological research. This study proposes a first morphological analysis of the whole Murghab alluvial fan in Turkmenistan, by means of the SRTM-DEM datum, and then the reconstruction of the ancient hydrography in the northeastern fringe of the fan, based on medium-high geometric resolution satellite data, and in continuity with previous studies. The importance to know historical fluvial network is due to the strict relationship between fresh water availability and human settlement distribution. SRTM-DEM, Corona, Soyouz KFA, Landsat, and Aster data were used, overlaying them in a GIS, and digitizing palaeochannels through photo-interpretation were done. Today, this is an almost desert area of the fan, and that is why it is easier to recognize buried forms by means of photo-interpretation, even though sometimes in a doubtful way. Despite the uncertainties, this model provided a useful tool for next and focused archaeological field surveys and excavations, aimed to find out human settlement evidences in correlation with ancient waterways.

A classification method of building structures based on multi-feature fusion of UAV remote sensing images

In order to improve the accuracy of building structure identification using remote sensing images,a building structure classification method based on multi-feature fusion of UAV remote sensing image is proposed in this paper.Three identification approaches of remote sensing images are integrated in this method:object-oriented,texture feature,and digital elevation based on DSM and DEM.So RGB threshold classification method is used to classify the identification results.The accuracy of building structure classification based on each feature and the multi-feature fusion are compared and analyzed.The results show that the building structure classification method is feasible and can accurately identify the structures in large-area remote sensing images.

A DEM Inversion Method for Inter-Tidal Zone Based on MODIS Dataset:A Case Study in the Dongsha Sandbank of Jiangsu Radial Tidal Sand-Ridges,China

Surthce elevation is tile basic data for geo-science. It is difficult to retrieve tidal-flats＇ elevation from a single Re- mote Sensing （RS） image because of the complicated sediment dynanical environment and huge spatial difference in tidal-flats＇ moisture content. A Digital Elevation Model （DEM） construction method for inconstant inter-tidal zone based on high tempo-resolution MODIS data set in a short period is proposed in a ease study on the Dongsha Sandbank of the Jiangsu Radial Tidal Sand-ridges. In the present study, a batch-preprocessing method based on image partition to handle massive MODIS IB images is developed and applied to 8163 scenes of MODIS images. The dataset of short-period and muhi-temporal MODIS images for inter-tidal flats＇ DEM inversion is selected and the usability of MODIS dataset is analyzed. Shorelines of the Dongsha Sandbank are extracted by use of batch supervised classification. In accord with tidal- 0 level forecasted by the Chenjiawu Tidal Gauge Station at the overpass moment of each RS image, DEMs of inter-tidal flats in January and sutmner（Jul, Aug and Sept）, 2003 are built under ArcG1S9.2. Studies show that： （1） The dataset of short-duration and muhi-phase MODIS images can be used to retrieve the historical DEM of tidal-flats at changeful tidal flats. （2） Aualysis on usability of MODIS images from Aqua and Terra indicates that there are more usable and higbquality MODIS images in spring, autumn and winter, but less in summer. Therefore, the period for building inter-tidal fiats＇ DEM is suggested to be one month in spring, autumn and winter and three months in summer.

Glacier variations and their response to climate change in an arid inland river basin of Northwest China

Glaciers are a critical freshwater resource of river recharge in arid areas around the world.In recent decades,glaciers have shown evidence of retreat due to climate change,and the accelerated ablation of glaciers and associated impacts on water resources have received widespread attention.Glacier variations result from climate change,so they can serve as an indicator of climate change.Considering the climatic differences in different elevation ranges,it is worthwhile to explore whether different responses exist between glacier area and air temperature in each elevation zone.In this study,we selected a typical arid inland river basin(Sugan Lake Basin)in the western Qilian Mountains of Northwest China to analyze the glacier variations and their response to climate change.The glacier area data from 1989 to 2016 were delineated using Landsat Thematic Mapper(TM),Enhanced TM+(ETM+)and Operational Land Imager(OLI)images.We compared the relationships between glacier area and air temperature at seven meteorological stations in the glacier-covered areas and in the Sugan Lake Basin,and further analyzed the relationship between glacier area and mean air temperature of the glacier surfaces in July–August in the elevation range of 4700–5500 m a.s.l.by the linear regression method and correlation analysis.In addition,based on the linear regression relationship established between glacier area and air temperature in each elevation zone,we predicted glacier areas under future climate scenarios during the periods of 2046–2065 and 2081–2100.The results indicate that the glaciers experienced a remarkable shrinkage from 1989 to 2016 with a shrinkage rate of–1.61 km^2/a(–0.5%/a),and the rising temperature is the decisive factor dominating glacial retreat;there is a significant negative linear correlation between glacier area and mean air temperature of the glacier surfaces in July–August in each elevation zone from 1989 to 2016.The variations in glaciers are far less sensitive to changes in precipitation than to changes in air temperature.Due to the influence of climate and topographic conditions,the distribution of glacier area and the rate of glacier ablation first increased and then decreased in different elevation zones.The trend in glacier shrinkage will continue because air temperature will continue to increase in the future,and the result of glacier retreat in each elevation zone will be slightly slower than that in the entire study area.Quantitative glacier research can more accurately reflect the response of glacier variations to climate change,and the regression relationship can be used to predict the areas of glaciers under future climate scenarios.These conclusions can offer effective references for assessing glacier variations and their response to climate change in arid inland river basins in Northwest China as well as other similar regions in the world.

Evidence for Accelerating Glacier Ice Loss in the Takht' e Solaiman Mountains of Iran from 1955 to 2010

This study reports on the clean ice area and surface elevation changes of the Khersan and Merjikesh glaciers in the north of Iran between 1955 and 2010 based on several high to medium spatial resolution remote sensing data.The object-oriented classification technique has been applied to nine remote sensing images to estimate the debris-free areas.The satellite-based analysis revealed that the clean ice areas of Khersan and Merjikesh glaciers shrank since 2010 with an overall area decrease of about 45% and 60% respectively.It means that the dramatic proportions of 1955 glaciers surface area are covered with debris during the last five decades.Although the general trend is a clean ice area decrease,some advancement is observed over the period of 1997-2004.During 1987-1991 the maximum decrease in the clean ice area was observed.However,the clean ice area had steadily increased between 1997 and 2010.To quantify the elevation changes besides the debris-free change analysis,several Digital Elevation Models(DEMs) were extracted from aerial photo(1955),topographic map(1997),ASTER image(2002) and Worldview-2 image(2010) and after it a 3-D Coregistration and a linear relationship adjustments techniques were used to remove the systematic shifts and elevation dependent biases.Unlike the sinusoidal variation of our case studies which was inferred from planimetric analysis,the elevation change results revealed that the glacier surface lowering has occurred during 1955-2010 continuously without any thickening with the mean annual thinning of about 0.4 ± 0.04 m per year and 0.3 ± 0.026 m per year for Khersan and Merjikesh glaciers,respectively.The maximum thinning rate has been observed during 1997-2002(about 1.1 ± 0.09 per year and 0.96 ± 0.01 mper year,respectively),which was compatible partially with debris-free change analysis.The present result demonstrates that although in debris-covered glaciers clean ice area change analysis can illustrate the direction of changes(retreat or advance),due to the high uncertainty in glacier area delineation in such glaciers,it cannot reveal the actual glacier changes.Thus,both planimetric and volumetric change analyses are very critical to obtain accurate glacier variation results.

Comparison of DEM accuracies generated from different stereo pairs over a plateau mountainous area

Digital elevation models(DEMs) can be quickly and conveniently generated using very high resolution(VHR) satellite stereo images. Previous studies have evaluated and compared DEM accuracy based on VHR satellite stereo pairs collected by different satellite sensors. However, few studies analyzed the accuracy of a DEM based on stereo image pairs from a satellite with the same orbit and different orbits for a region with significant topographic fluctuations in the plateau area. Referring to former studies, this paper had two objectives: to generate a digital elevation model(DEM) and evaluate its horizontal and vertical accuracy over a plateau area with high relief;and to study the mapping capability of multiorbit and multitemporal stereo pair images in the plateau mountainous region. To achieve these objectives, we collected the 2015 Worldview-2 stereo image pair and another three World View-2 images acquired in 2013, 2014, and 2015. First, the 2015 DEM was obtained using a strict physical model based on along-track stereo image pairs, and the reliability of the DEM was verified with field data. Then, the images obtained in 2013, 2014, and 2015 were combined into different-orbit stereo image pairs, DEMs were produced using rational function models, and the DEMs were verified using field data and the 2015 DEM as standards. The results showed that the relief degree has a particular influence on the DEM, and the precision of the DEM decreases as the topographic relief increases. Off-nadir angles can also influence DEM accuracy, with a larger angle corresponding to a lower DEM accuracy. The research also shows that the DEM obtained from four sets of experiments meets the accuracy requirement of a 1:5,000 digital elevation map, digital line graphic(DLG), and digital orthophoto map(DOM). Among these four groups of DEMs, the one based on the 2015 stereo pairs with the same satellite achieved the highest precision.

Morphotectonic and Lithostratigraphic Analysis of Intermontane Karewa Basin of Kashmir Himalayas,India

Morpho-tectonic study plays an important role in deciphering the effects of tectonic activity in the geomorphic evolution of the drainage basins.Romushi watershed forms one of the major watersheds of the intermontane Karewa Basin of Kashmir Valley.The Karewa sediments are characterized by glacio-fluvio-lacustrine deposits capped by the aeolian loess.The geomorphic,morphometric and lithostratigraphic studies of these cap deposits have been carried out to elucidate the effect of tectonics on the geomorphic evolution of Romushi Watershed.Geomorphic mapping was carried out using GPS measurements,DEM at 30m resolution,Topographic Position Index(TPI) model,topographic maps,LANDSAT TM Imagery and field data.Morphometric and morphotectonic analyses in GIS environment were used to calculate various geomorphic indices(Mountain Front Sinuosity Index,Bifurcation Ratio,Asymmetry Factor,River Profile,etc).These indices reveal that the tectonic uplift observed in the region due to Himalayan orogeny coupled with mass movement and aeolian deposition have dominated the landscape evolution of intermontane Karewa Basin of Kashmir throughout the Late Quaternary Period.Additional data from lithostratigraphic measurements were analyzed to understand the geomorphic evolution of intermontane Karewa Basin.The data revealed that the basin has experienced differential uplift and erosion rates from time to time in the geological past.This was corroborated by the results from the morphometric and morphotectonic analysis.

Distribution of Initial Vegetation Recruitment on Bare Bar in Sand Bed River

Riparian vegetation is known to affect the flood flow and the riparian environment, and it is important for river engineers to know the vegetation dynamics in river. Despite a number of researches have been performed for vegetation dynamics, the mechanism of initial vegetation recruitment is still not clear. In this study, two field surveys by using Unmanned Aerial Vehicle (UAV) remote sensing, UAV aerial photographs analysis and a numerical simulation were conducted to detect the location of initial vegetation recruitment and explore its relationship with hydrology and river morphology. The initial vegetation recruitment was identified by comparing vegetation distributions before and after vegetation germination. Most of the initial vegetation recruitment locations were found either along dunes on sandbar or along the wet/dry rotational area of shore bank. Results of the aerial photographs analysis showed that the initial vegetation recruitment occurred at the downstream side of crest of dunes. As for the vegetation recruitment zone located along shore bank, the relative elevation of different recruitment zones is almost same, and the mean value of the relative elevation is around 0.33 m. With the comparison of the contour map of river morphology and the initial vegetation recruitment zone, the shape of initial vegetation recruitment zone is positively consistent with the shape of river morphology distribution. The results of numerical analysis show that the initial vegetation recruitment zone located along shore bank experienced intermediate flood pulse. The inundation frequencies during seed dispersal and germination period for the internal and external boundaries of vegetation recruitment zone are 23.87% and 6.2%, respectively.

Elevation change of the Urumqi Glacier No.1 derived from Sentinel-1A data

Accurate measurements of glacier elevation changes play a crucial role in various glaciological studies related to glacier dynamics and mass balance. In this paper, glacier elevation changes of Urumqi Glacier No.1 between August 2015 and August 2017 were investigated using Sentinel-1 A data and DInSAR technology. Meanwhile, the atmospheric delay error was corrected with the MODIS MOD05L2 products. The weight selection iteration method was applied to calibrate the glacier elevation changes in the mass balance years 2015-2016 and 2016-2017. Finally, the geodetic method was employed to calculate the elevation change values of individual stakes of Urumqi Glacier No.1. Moreover, the elevation change values corrected by the weight selection iteration method were verified. Results showed as follows:(1) the elevation of Urumqi Glacier No.1 glacier affected by atmospheric delay was 1.270 cm from 2015 to 2016. The glacier elevation affected by atmospheric delay from 2016 to 2017 was 1.071 cm.(2) The elevation change value of Urumqi Glacier No.1 was-1.101 m from 2015 to 2016, and the elevation of Urumqi Glacier No.1 decreased by 1.299 m from 2016 to 2017. The overall thickness of Urumqi Glacier No. 1 was thinning.(3) By comparing the elevation change results of individual stakes with corresponding points corrected by the weight selection iteration method, the mean squared errors of difference were 0.343 m and 0.280 m between the two mass balance years, respectively.(4) The accuracy of elevation change in non-glaciated areas was 0.039 m from 2015 to 2016 and 0.034 m from 2016 to 2017. Therefore, it is reliable to use Sentinel-1 A data and the study method proposed in this paper to calculate the elevation change of mountain glaciers with very low horizontal movement.

Quantifying the Accuracy of LiDAR-Derived DEM in Deciduous Eastern Forests of the Cumberland Plateau

Digital elevation models (DEMs) derived from light detection and ranging (LiDAR) technology are becoming the standard in representing terrain surfaces. They have numerous applications in forestry, agriculture, and natural resources. Although elevation errors are much lower than those derived from traditional methods, accuracies have been reported to decrease with terrain slope and vegetation cover. In this study, we quantified the accuracy of airborne LiDAR-derived DEM in deciduous eastern forests of the Cumberland Plateau. We measured relative elevation changes within field plots located across different slope and ruggedness classes to quantify DEM accuracy. We compared elevation change errors of DEMs derived from three LiDAR datasets: a low-density (~1.5 pts•m−2), a high-density (~40 pts•m−2), and a combined dataset. We also compared DEMs obtained by interpolating the ground points using four interpolation methods. Results indicate that mean elevation change error (MECE) increased with terrain slope and ruggedness with an average of 73.6 cm. MECE values ranged from 23.2 cm in areas with lowest slope (0% - 39%) and ruggedness (0% - 28%) classes to 145.5 cm in areas with highest slope (50% - 103%) and ruggedness (46% - 103%) classes. We found no significant differences among interpolation methods or LiDAR datasets;the latter of which indicates that similar accuracy levels can be achieved with the low-density datasets.

Altimetry Quality of SRTM and ASTER GDEM Products for Areas with Different Reliefs

Hydroelectric power plants cause impacts that are usually estimated by an indicator, the hydroelectric power generation per hectare of flooded area. And, although entrepreneurs use quality-declared cartographic bases to comply with the standards, at the project stages of a hydroelectric plant it is not a priori determined whether the altimetry tolerance of such bases is sufficient to ensure that the impacts will not increase, which in the project consolidation becomes a huge problem. This work aims to define the altimetry quality of SRTM Digital Elevation Models (DEM) and ASTER GDEM and whether they are a priori sufficient to simulate the flood level of hydroelectric power plants in different reliefs. To accomplish this objective, a morphological method of assessment of the DEM quality was developed, through Geographic Information Systems (GIS), so that the altimetry information generated by the models and field surveys, when compared, would show their actual differences also in relation to their areas. To this end, two study areas were used: one with a slightly undulated relief and the other with undulated relief. To validate the models, quality assessments were carried out: based on points, according to the Brazilian Map Accuracy Standard (MAS) and STANAG 2215;and based on surfaces, according to Article 500 of the Brazilian Civil Code and the morphological method. At the end, practical applications relating to the M&P indicator and hydroelectric power plants projects were also carried out. The results presented demonstrate that the quality of an SRTM DEM when used in undulating or gently undulating reliefs can be used up to 1:80,000 scale. Already for DEM ASTER under the same conditions, it is possible to use on the scale 1:100,000. In DEM SRTM and DEM ASTER, after removing the systematic error (−7.3 m) and (−6.2 m), respectively, the quality between 65% and 79% is verified for DEM SRTM and 53%, and 68% for DEM ASTER for common areas in flood level simulation.

阳江地区咸酸田土地改良的试验研究

通过对阳江地区沿海丢荒的咸酸田进行地力监测,通过“水改+肥改”措施对土壤改良,引入水稻-禾虫综合种养模式改善土壤生态,并持续地力监测,评估经济效益。以期达到沿海咸酸田生态环境改善、水稻提质增效和丢荒农田复耕的目的,为治理土壤污染、修复耕地提供有益参考。

电梯门系统故障在线监测技术研究

本文在分析电梯门系统常见故障现象基础上,选取振动加速度、位移、电流三个物理参数来表征电梯门系统运行状态;搭建的实验平台上设置了振动加速度传感器、红外线位移传感器、霍尔传感器,采集门系统的振动加速度、开关门位移、门机电流三个运行状态数据,并通过人为设置故障,在实验状态下获得典型故障特征数据,并提取了门系统常见故障特征曲线。应用电梯门系统在线监测技术,可实时在线监测门系统的运行,并快速、准确定位门系统故障,实现门系统故障诊断。

基于间接高差法的自动化竖向位移监测方法研究

目前,针对铁路及轨道交通既有线结构物监测工作,相关管理部门要求采用自动化监测手段,并需要将监测数据实时上传至监测网络平台,而传统的人工几何水准测量方法十分耗时耗力,已不能满足该行业监测的相关要求。为了解决全站仪自动化竖向位移监测精度达不到人工几何水准测量精度的问题,采用间接高差测量的基本原理方法,获取相邻监测点间的间接高差,以减弱地球曲率和大气折光对竖向位移监测的影响。首先以“相邻监测点观测距离相近”的原则进行监测路线自动化设计;接着对自动化测量得到的天顶距、距离进行预处理,以判断外业观测数据是否超限,进而保证原始观测数据精度;最后进行水准测量线路平差,计算出每个监测点的高程值。实测结果表明,在相邻监测点测距相差较小的情况下采用0.5″全站仪可以达到二等水准精度要求。