scholarly journals Influence of Flight Height on The Accuracy of UAV Derived Digital Elevation Model at Complex Terrain

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Nguyen QUOC LONG ◽  
Ropesh GOYAL ◽  
Bui KHAC LUYEN ◽  
Le VAN CANH ◽  
Cao XUAN CUONG ◽  
...  
Keyword(s):  
Complex Terrain ◽  
Mining Industry ◽  
Open Pit ◽  
Control Points ◽  
Open Pit Mines ◽  
Ground Control Points ◽  
Digital Elevation ◽  
Flight Height ◽  
Aerial Vehicle ◽  
Elevation Model

Lightweight Unmanned Aerial Vehicle (UAV) for 3D topographic mapping in mining industry has been raised significantly in recent years. Especially, in complex terrains such as in open-pit mines in which the elevation is rapidly undulating, UAV-based mapping has proven its economical efficiency and higher safety compared to the conventional methods. However, one of the most important factors in UAV mapping of complex terrain is the flight altitude, which needs to be considered seriously because of the safety and accuracy of generated DEMs. This paper aims to evaluate the influence of the flight height on the accuracy of DEMs generated in open-pit mines. To this end, the study area is selected in a quarry with a complex terrain, which is located in northern Vietnam. The investigation was conducted with five flight heights of 50 m, 100 m, 150 m, 200 m, and 250 m. To assess the accuracy of resulting DEMs, ten ground control points (GCPs), and 385 checkpoints measured by both GNSS/RTK and total station methods were used. The accuracy of DEM was assessed by root-mean-square error (RMSE) in X, Y, Z, XY, and XYZ components. The results show that DEM models generated at the flight heights of less than 150 m have high accuracy. RMSEs of the 10 GCPs increase from 1.8 cm to 6.2 cm for the vertical (Z), and from 2.6 cm to 6.3 cm for the horizontal (XY), whereas RMSE of 385 checkpoints increase gradually from 0.05 m to 0.15 m for the vertical (Z) when the flight height increases from 50 m to 250 m.

scholarly journals Experimental Investigation on the Performance of DJI Phantom 4 RTK in the PPK Mode for 3D Mapping Open-Pit Mines

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Le VAN CANH ◽  
Cao XUAN CUONG ◽  
Nguyen QUOC LONG ◽  
Le THI THU HA ◽  
Tran TRUNG ANH ◽  
...  
Keyword(s):  
Coal Mines ◽  
Daily Basis ◽  
Open Pit ◽  
Surface Model ◽  
Test Field ◽  
Open Pit Mines ◽  
Ground Control Points ◽  
Aerial Vehicle ◽  
Topographic Surveys

Open-pit coal mines’ terrain is often complex and quickly and frequently changes. Therefore, topographic surveys of open-pit mines are undertaken on a daily basis. While these tasks are very time-consuming and costly with traditional methods such as total station and GNSS, the unmanned aerial vehicle (UAV) based method can be more efficient. This method is a combination of the “Structure from motion” (SfM) photogrammetry technique and UAV photogrammetry which has been widely used in topographic surveying. With an increasing popularity of RTK-enabled drones, it is becoming even more powerful method. While the important role of ground control points (GCP) in the accuracy of digital surface model (DSM) generated from images acquired by “traditional” UAVs (not RTK-enabled drones) has been proved in many previous studies, it is not clear in the case of RTK-enabled drones, especially for complex terrain in open-pit coal mines. In this study, we experimentally investigated the influence of GCP regarding its numbers and distribution on the accuracy of DSM generation from images acquired by RTK-enabled drones in open-pit coal mines. In addition, the Post Processing Kinematic (PPK) mode was executed over a test field with the same flight altitude. DSM generation was performed with several block control configurations: PPK only, PPK with one GCP, and PPK with two GCPs. Several positions of GCPs were also examined to test the optimal locations for placing GCPs to achieve accurate DSMs. The results show that the horizontal and vertical accuracy given by PPK only were 9.3 and 84.4 cm, respectively. However, when adding at least one GCP, the accuracy was significantly improved in both horizontal and vertical components, with RMSE for XY and Z ranging between 3.8 and 9.8 cm (with one GCP) and between 3.0 and 5.7 cm (with two GCPs), respectively. Also, the GCPs placed in the deep areas of the open-pit mine could ensure the cm-level accuracy.

scholarly journals Detecting drainage pitfalls in open-pit mines and haul roads using UAV-photogrammetry

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 190-195
Author(s):  
Felipe Dille Benevenuti ◽  
Rodrigo De Lemos Peroni
Keyword(s):  
Three Dimensional ◽  
Open Pit ◽  
Road Maintenance ◽  
Open Pit Mines ◽  
Cycle Times ◽  
Course Material ◽  
Aerial Vehicle ◽  
Haul Road ◽  
Elevation Model

Open-pit mines generally have operational problems such as puddling and inappropriate water flow over haul roads, particularly if located in areas with high rainfall indices. These situations increase truck cycle times, promote rapid deterioration of haul-road wearing-course material, reduce productivity due to downtime and increase road maintenance. In addition, operational costs are raised as the frequency of truck maintenance and tire failures also increase. The use of a high-resolution three-dimensional elevation model, created based on Unmanned Aerial Vehicle (UAV) photogrammetry, has been shown to be an effective technique to detect anomalies in a fast and precise way. With the proposed approach, it is possible to diagnose haul-road conditions after rainfall or to anticipate the potential occurrence of such anomalies before they become a greater problem. This diagnosis can then be used to prioritize maintenance activities in open-pit mines. To describe the methodology, a case study is presented demonstrating and validating the results obtained.

scholarly journals Accuracy assessment of open - pit mine’s digital surface models generated using photos captured by Unmanned Aerial Vehicles in the post - processing kinematic mode

2021 ◽  
Vol 62 (4) ◽  
pp. 38-47
Author(s):  
Long Quoc Nguyen ◽  
Keyword(s):  
Accuracy Assessment ◽  
Open Pit ◽  
Ground Control ◽  
Surface Model ◽  
Control Points ◽  
Post Processing ◽  
Ground Control Points ◽  
Satellite Positioning ◽  
Surface Models ◽  
Aerial Vehicle

To evaluate the accuracy of the digital surface model (DSM) of an open-pit mine produced using photos captured by the unmanned aerial vehicle equipped with the post-processing dynamic satellite positioning technology (UAV/PPK), a DSM model of the Deo Nai open-pit coal mine was built in two cases: (1) only using images taken from UAV/PPK and (2) using images taken from UAV/PPK and ground control points (GCPs). These DSMs are evaluated in two ways: using checkpoints (CPs) and comparing the entire generated DSM with the DSM established by the electronic total station. The obtained results show that if using CPs, in case 1, the errors in horizontal and vertical dimension were 6.8 and 34.3 cm, respectively. When using two or more GCPs (case 2), the horizontal and vertical errors are at the centimetre-level (4.5 cm and 4.7 cm); if using the DSM comparison, the same accuracy as case 2 was also obtained.

scholarly journals 3-D modelling and visualization of large building using photogrammetric approach

2021 ◽  
Author(s):  
Raad Awad Kattan ◽  
◽  
Farsat Heeto Abdulrahman ◽  
Sami Mamlook Gilyana ◽  
Yousif Youkhna Zaya ◽  
...  
Keyword(s):  
Bundle Adjustment ◽  
Ground Control ◽  
Control Points ◽  
Distance Measurements ◽  
Ground Control Points ◽  
Digital Elevation ◽  
Elevation Model ◽  
College Of Engineering ◽  
User Friendly ◽  
D Model

The progress in modern technologies such as precise lightweight cameras mounted on unmanned aerial vehicles (UAV) and the more user-friendly software in the photogrammetric field, allows for 3-D model construction of any structure or shape. Software now achieves in sequence the processes of matching, generating tie points, block bundle adjustment, and generating digital elevation models.The aim of this study is to make a virtual 3-D model of the college of engineering /University of Duhok. Kurdistan Region, Iraq. The data input is vertical and oblique imagery acquired by UAV, ground control points distributed on the surrounded ground, facades, and roof. Ground control points were measured by the GPS RTK system in addition to the reflectorless total station instrument. The data is processed mainly using Agisoft PhotoScan software as well as the Global Mapper and the ReCap software. The output is a 3-D model, digital elevation model, and orthomosaic.Geometric and visual inspections were carried out. Some imperfections appeared on the sharp edges and parapets of the building. In the geometric accuracy of selected points on the building, the maximum standard deviation in the coordinates was ±4cm. The relative accuracy in distance measurements were in the range of 0.72% to 4.92 %

scholarly journals EVALUATION OF ASTER GDEM V3 USING ICESAT LASER ALTIMETRY

2016 ◽  
Vol XLI-B4 ◽  
pp. 117-124
Author(s):  
C. C. Carabajal ◽  
J.-P. Boy
Keyword(s):  
Thermal Emission ◽  
Ground Control ◽  
Control Points ◽  
Ice Cloud ◽  
Aster Gdem ◽  
Ground Control Points ◽  
Digital Elevation ◽  
Elevation Model ◽  
Globally Distributed

We have used a set of Ground Control Points (GCPs) derived from altimetry measurements from the Ice, Cloud and land Elevation Satellite (ICESat) to evaluate the quality of the 30 m posting ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) Global Digital Elevation Model (GDEM) V3 elevation products produced by NASA/METI for Greenland and Antarctica. These data represent the highest quality globally distributed altimetry measurements that can be used for geodetic ground control, selected by applying rigorous editing criteria, useful at high latitudes, where other topographic control is scarce. Even if large outliers still remain in all ASTER GDEM V3 data for both, Greenland and Antarctica, they are significantly reduced when editing ASTER by number of scenes (N≥5) included in the elevation processing. For 667,354 GCPs in Greenland, differences show a mean of 13.74 m, a median of -6.37 m, with an RMSE of 109.65 m. For Antarctica, 6,976,703 GCPs show a mean of 0.41 m, with a median of -4.66 m, and a 54.85 m RMSE, displaying smaller means, similar medians, and less scatter than GDEM V2. Mean and median differences between ASTER and ICESat are lower than 10 m, and RMSEs lower than 10 m for Greenland, and 20 m for Antarctica when only 9 to 31 scenes are included.

scholarly journals Rectification of Bowl-Shape Deformation of Tidal Flat DEM derived from UAV Imaging

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1602 ◽  
Author(s):  
Hyoseong Lee ◽  
Dongyeob Han
Keyword(s):  
Tidal Flat ◽  
Tidal Flats ◽  
Control Points ◽  
Matching Method ◽  
Height Difference ◽  
Ground Control Points ◽  
Digital Elevation ◽  
Aerial Vehicle ◽  
Rotation Parameters ◽  
Uav Images

It is necessary to periodically obtain topographic maps of the geographical and environmental characteristics of tidal flats to systemically manage and monitor them. Accurate digital elevation models (DEMs) of the tidal flats are produced while using ground control points (GCPs); however, it is both complicated and difficult to conduct GPS surveys and readings of image coordinates that correspond to these because tidal flat areas are not easy to access. The position and distribution of GCPs affect DEMs, because the entire working area cannot be covered during a survey. In this study, a least-squares height-difference (LHD) DEM matching method with a polynomial model is proposed to increase the number of DEM grids while using a presecured precise DEM to rectify the distortion and bowl effect produced by unmanned aerial vehicle (UAV) images. The most appropriate result was obtained when the translation parameters were quadratic curve polynomials with an increasing number of grids and the rotation parameters were constant. The experimental results indicated that the proposed method reduced the distortion and eliminated the error caused by the bowl effect while only using a reference DEM.

scholarly journals Continuous Monitoring and Improvement of the Blasting Process in Open Pit Mines Using Unmanned Aerial Vehicle Techniques

2020 ◽  
Vol 12 (17) ◽  
pp. 2801
Author(s):  
Thomas Bamford ◽  
Filip Medinac ◽  
Kamran Esmaeili
Keyword(s):  
Unmanned Aerial Vehicle ◽  
High Speed ◽  
Field Experiments ◽  
Block Size ◽  
Structural Data ◽  
Open Pit ◽  
Open Pit Mines ◽  
Digital Elevation ◽  
Aerial Vehicle ◽  
Technical Manpower

The current techniques used for monitoring the blasting process in open pit mines are manual, intermittent and inefficient and can expose technical manpower to hazardous conditions. This study presents the application of unmanned aerial vehicle (UAV) systems for monitoring and improving the blasting process in open pit mines. Field experiments were conducted in different open pit mines to assess rock fragmentation, blast-induced damage on final pit walls, blast dynamics and the accuracy of blastholes including production and pre-split holes. The UAV-based monitoring was done in three different stages, including pre-blasting, blasting and post-blasting. In the pre-blasting stage, pit walls were mapped to collect structural data to predict in situ block size distribution and to develop as-built pit wall digital elevation models (DEM) to assess blast-induced damage. This was followed by mapping the production blasthole patterns implemented in the mine to investigate drillhole alignment. To monitor the blasting process, a high-speed camera was mounted on the UAV to investigate blast initiation, sequencing, misfired holes and stemming ejection. In the post-blast stage, the blasted rock pile (muck pile) was monitored to estimate fragmentation and assess muck pile configuration, heave and throw. The collected aerial data provide detailed information and high spatial and temporal resolution on the quality of the blasting process and significant opportunities for process improvement. The current challenges with regards to the application of UAVs for blasting process monitoring are discussed, and recommendations for obtaining the most value out of an UAV application are provided.

scholarly journals GENERATION AND EVALUATION OF RADARGRAMMETRIC DEM FROM RADARSAT-1 STANDARD IMAGES IN LOW RELIEF AREA IN THE AMAZON COASTAL PLAIN

2014 ◽  
Vol 32 (3) ◽  
pp. 405 ◽  
Author(s):  
Edson Adjair de Souza Pereira ◽  
Pedro Walfir M. Souza-Filho ◽  
Waldir R. Paradella ◽  
Wilson Da Rocha Nascimento Jr.
Keyword(s):  
Coastal Plain ◽  
Geometric Modeling ◽  
Specific Model ◽  
Depth Information ◽  
Control Points ◽  
Ground Control Points ◽  
Digital Elevation ◽  
Imaging Mode ◽  
Elevation Model ◽  
Relief Area

ABSTRACT. The generation of digital elevation models (DEMs) from the Standard imaging mode of RADARSAT-1 stereo-images was investigated to evaluate theviability of producing 1:100,000 scale altimetric maps in areas with a low topographic relief on the Brazilian Amazon coastal plain. Absolute DEMs were generatedusing RADARSAT-1 Standard stereopairs (S2Asc/S1Des, S6Des/S1Des, and S7Asc/S6Des) with ground control points collected using a Differential Global Positioningsystem. The geometric modeling for the DEM extractions was based on the “RADARSAT Specific Model” from the OrthoEngine Satellite Edition of the PCI Geomaticasoftware; this model is an automated matching solution that considers the slant range distances from sensors and terrain. Thirteen independent control points were usedto validate the accuracy of the absolute DEM. Only the S2Asc/S1Des pair was effective in highlighting depth information, which was a result of the pair’s intermediateintersection angle (47◦) and higher vertical parallax ratio (4.31). Therefore, RADARSAT-1 Standard images are a useful alternative for generating absolute DEM at thescale of 1:100,000 in cartographic gap areas on the Amazon coastal plain.Keywords: digital elevation model, stereoscopy, RADARSAT-1, Amazon, Brazil. RESUMO. A geração de modelos digitais de elevação (MDEs) a partir de pares estereoscópicos RADARSAT-1 modo Standard foi empregada com o objetivo deavaliar a produção de mapa altimétrico na escala de 1:100.000 em uma área de baixo relevo na planície costeira amazônica. MDEs absolutos foram gerados usandopares estereoscópicos RADARSAT-1 Standard (S2Asc/S1Des, S6Des/S1Des e S7Asc/S6Des) com pontos de controle do terreno coletados usando-se um sistema deposicionamento global diferencial. Omodelamento geométrico para extração doMDE foi baseado no “Modelo Específico para o RADARSAT”, do programa PCIGeomatica, através do cálculo que maximiza o coeficiente de correlação e leva em consideração as distâncias no alcance inclinado entre o sensor e o terreno. Para a validação do MDE absoluto foram usados 13 pontos de controle independentes. Apenas o par S2Asc/S1Des foi eficaz no realce da informação de profundidade, devido aos ângulos de intersecção intermediários (47◦), mas principalmente, devido a maior razão da paralaxe vertical observada (4,31). Portanto, as imagens RADARSAT-1 Standard representam uma ótima alternativa para a produção de MDEs absolutos na escala de 1:100.000 em áreas com vazios cartográficos na planície costeira amazônica.Palavras-chave: modelo digital de elevação, estereoscopia, RADARSAT-1,Amazônia, Brasil.

scholarly journals DEM Generation from Fixed-Wing UAV Imaging and LiDAR-Derived Ground Control Points for Flood Estimations

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3205 ◽  
Author(s):  
Jairo R. Escobar Villanueva ◽  
Luis Iglesias Martínez ◽  
Jhonny I. Pérez Montiel
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Structure From Motion ◽  
Local Level ◽  
Control Point ◽  
Ground Control ◽  
Control Points ◽  
Ground Control Points ◽  
Digital Elevation ◽  
Elevation Data ◽  
Aerial Vehicle

Geospatial products, such as digital elevation models (DEMs), are important topographic tools for tackling local flood studies. This study investigates the contribution of LiDAR elevation data in DEM generation based on fixed-wing unmanned aerial vehicle (UAV) imaging for flood applications. More specifically, it assesses the accuracy of UAV-derived DEMs using the proposed LiDAR-derived control point (LCP) method in a Structure-from-Motion photogrammetry processing. Also, the flood estimates (volume and area) of the UAV terrain products are compared with a LiDAR-based reference. The applied LCP-georeferencing method achieves an accuracy comparable with other studies. In addition, it has the advantage of using semi-automatic terrain data classification and is readily applicable in flood studies. Lastly, it proves the complementarity between LiDAR and UAV photogrammetry at the local level.

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