Charcoal heaps volume estimation based on unmanned aerial vehicles.

Abstract The charcoal stock in a forest company is controlled based on the theoretical capacity of the masonry ovens (input) and shipped trucks (output). During the year, the company must monitor the stock for the purposes of accountability reports. This study proposes a more efficient and equally precise survey method that overcomes the challenges of the common monitoring system in Brazil. During this study, a new monitoring method based on digital stereoscopy from UAV images was developed, implemented and evaluated. The results were compared with a traditional topographic survey. A masonry oven's complex containing eight charcoal heaps was flown and surveyed using a multi-engine UAV, with an integrated Global Navigation Satellite System (GNSS) and RTK equipment. Two stereoscopic processing methods were applied: (1) very low quality and (2) high quality to image alignment, reconstruction of the dense cloud, face count and in three-dimensional mesh creation. Low quality products showed geometric deformities when compared to high quality, but resulted in similar estimation to the topographic survey. The results indicated that the charcoal heaps' volume estimation using UAV derived orthomosaics can replace the conventional method of GNSS RTK surveys with considerable gains in stockpile volume accuracy, inventory frequency, and safety. In the case of high accuracy parameterization, improvements in geometric precision and accuracy are also produced.

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An Integrated Approach for Mapping Three-Dimensional CoSeismic Displacement Fields from Sentinel-1 TOPS Data Based on DInSAR, POT, MAI and BOI Techniques: Application to the 2021 Mw 7.4 Maduo Earthquake

Remote Sensing ◽

10.3390/rs13234847 ◽

2021 ◽

Vol 13 (23) ◽

pp. 4847

Author(s):

Lang Xu ◽

Qiang Chen ◽

Jing-Jing Zhao ◽

Xian-Wen Liu ◽

Qian Xu ◽

...

Keyword(s):

Three Dimensional ◽

Integrated Approach ◽

Satellite System ◽

Displacement Fields ◽

Fusion Algorithm ◽

High Quality ◽

Integrated Method ◽

Global Navigation Satellite ◽

Interferometric Sar ◽

Mean Square Errors

Sentinel-1 Terrain Observation by Progressive Scans (TOPS) data have been widely applied in earthquake studies due to their open-source policy, short revisit cycle and wide coverage. However, significant near-fault displacement gradients and the moderate azimuth resolution of TOPS data make achieving high-precision along-track measurements challenging, which prevents the generation of high-quality three-dimensional (3D) displacement maps. Here, we propose an integrated method to retrieve high-quality 3D displacements based on the differential interferometric SAR (DInSAR), burst-overlap interferometry (BOI), multiple-aperture InSAR (MAI) and pixel offset tracking (POT) techniques, which are achieved to use only two track Sentinel-1 TOPS data with different viewing geometries. The key step of this method is using a weighted fusion algorithm with the interpolated BOI-derived and MAI-derived 3D displacements. In a case study of the 2021 Maduo earthquake, the calculated root mean square errors (RMSEs) from global navigation satellite system (GNSS) data and the InSAR-derived 3D displacement fields were found to be 6.3, 5.8 and 1.7 cm in north–south, east–west and up–down components, respectively. Moreover, the slip model of the 2021 Maduo earthquake jointly estimated by DInSAR and BOI measurements indicates that this seismic event was dominated by sinistral strike-slip motion mixed with some dip-slip movements; the estimated seismic moment was 1.75 × 1020 Nm, corresponding to a Mw 7.44 event.

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EGNOS Based APV Procedures Development Possibilities In The South-Eastern Part Of Poland

Annual of Navigation ◽

10.1515/aon-2015-0007 ◽

2014 ◽

Vol 21 (1) ◽

pp. 85-94 ◽

Cited By ~ 3

Author(s):

Wojciech Z. Kaleta

Keyword(s):

Three Dimensional ◽

Dimensional Accuracy ◽

Satellite System ◽

Civil Aviation ◽

The South ◽

South Eastern ◽

System Integrity ◽

New Instrument ◽

Global Navigation Satellite ◽

First Time

AbstractOn 14th and 15th March 2011 for the first time approach with vertical guidance (APV-I) was conducted on Polish territory in Katowice, Kraków and Mielec. This was the milestone for GNSS (Global Navigation Satellite System) and Area Navigation (RNAV) use as a new instrument approach chance for NPA (Non-Precision Approach) and PA (Precision Approach) in Poland. The paper presents the experiment study of EGNOS SIS (Signal in Space) due to APV (Approach with Vertical Guidance) procedures development possibilities in the south-eastern part of Poland. Researches were conducted from January 2014 till June 2014 in three Polish cities: Warszawa, Kraków and Rzeszów. EGNOS as SBAS (Satellite Based Augmentation System) in according with ICAO's Annex 10 has to meet restrictive requirements for three dimensional accuracy, system integrity, availability and continuity of SIS. Because of ECAC (European Civil Aviation Conference) states to EGNOS coverage in the eastern part of Europe, location of mention above stations, shows real usefulness for SIS tests and evaluation of the results [EUROCONTROL, 2008].

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Algorithm for Generating 3D Geometric Representation Based on Indoor Point Cloud Data

Applied Sciences ◽

10.3390/app10228073 ◽

2020 ◽

Vol 10 (22) ◽

pp. 8073

Author(s):

Min Woo Ryu ◽

Sang Min Oh ◽

Min Ju Kim ◽

Hun Hee Cho ◽

Chang Baek Son ◽

...

Keyword(s):

Point Cloud ◽

Indoor Environment ◽

Three Dimensional ◽

Satellite System ◽

Normal Vector ◽

Geometric Representation ◽

Point Cloud Data ◽

Cloud Data ◽

Data Process ◽

Global Navigation Satellite

This study proposes a new method to generate a three-dimensional (3D) geometric representation of an indoor environment by refining and processing an indoor point cloud data (PCD) captured through backpack laser scanners. The proposed algorithm comprises two parts to generate the 3D geometric representation: data refinement and data processing. In the refinement section, the inputted indoor PCD are roughly segmented by applying random sample consensus (RANSAC) to raw data based on an estimated normal vector. Next, the 3D geometric representation is generated by calculating and separating tangent points on segmented PCD. This study proposes a robust algorithm that utilizes the topological feature of the indoor PCD created by a hierarchical data process. The algorithm minimizes the size and the uncertainty of raw PCD caused by the absence of a global navigation satellite system and equipment errors. The result of this study shows that the indoor environment can be converted into 3D geometric representation by applying the proposed algorithm to the indoor PCD.

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An Analysis of Alternatives for the COSMIC-2 Constellation in the Context of Global Observing System Simulation Experiments

Weather and Forecasting ◽

10.1175/waf-d-19-0185.1 ◽

2020 ◽

Vol 35 (1) ◽

pp. 51-66 ◽

Cited By ~ 1

Author(s):

L. Cucurull ◽

M. J. Mueller

Keyword(s):

System Simulation ◽

Three Dimensional ◽

Lower Troposphere ◽

Weather Forecast ◽

Satellite System ◽

Forecast Skill ◽

Added Value ◽

Simulation Experiments ◽

Global Navigation Satellite ◽

The Impact

Abstract Observing system simulation experiments (OSSEs) were conducted to evaluate the potential impact of the six Global Navigation Satellite System (GNSS) radio occultation (RO) receiver satellites in equatorial orbit from the initially proposed Constellation Observing System for Meteorology, Ionosphere, and Climate-2 (COSMIC-2) mission, known as COSMIC-2A. Furthermore, the added value of the high-inclination component of the proposed mission was investigated by considering a few alternative architecture designs, including the originally proposed polar constellation of six satellites (COSMIC-2B), a constellation with a reduced number of RO receiving satellites, and a constellation of six satellites but with fewer observations in the lower troposphere. The 2015 year version of the operational three-dimensional ensemble–variational data assimilation system of the National Centers for Environment Prediction (NCEP) was used to run the OSSEs. Observations were simulated and assimilated using the same methodology and their errors assumed uncorrelated. The largest benefit from the assimilation of COSMIC-2A, with denser equatorial coverage, was to improve tropical winds, and its impact was found to be overall neutral in the extratropics. When soundings from the high-inclination orbit were assimilated in addition to COSMIC-2A, positive benefits were found globally, confirming that a high-inclination orbit constellation of RO receiving satellites is necessary to improve weather forecast skill globally. The largest impact from reducing COSMIC-2B from six to four satellites was to slightly degrade weather forecast skill in the Northern Hemisphere extratropics. The impact of degrading COSMIC-2B to the COSMIC level of accuracy, in terms of penetration into the lower troposphere, was mostly neutral.

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Hybrid 3D Models: When Geomatics Innovations Meet Extensive Built Heritage Complexes

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi8030124 ◽

2019 ◽

Vol 8 (3) ◽

pp. 124 ◽

Cited By ~ 6

Author(s):

Filiberto Chiabrando ◽

Giulia Sammartano ◽

Antonia Spanò ◽

Alessandra Spreafico

Keyword(s):

Three Dimensional ◽

Laser Scanner ◽

3D Models ◽

Satellite System ◽

3D Data ◽

Mapping System ◽

Aerial Vehicle ◽

Mobile Mapping System ◽

Global Navigation Satellite ◽

Topographic Surveys

This article proposes the use of a multiscale and multisensor approach to collect and model three-dimensional (3D) data concerning wide and complex areas to obtain a variety of metric information in the same 3D archive, which is based on a single coordinate system. The employment of these 3D georeferenced products is multifaceted and the fusion or integration among different sensors’ data, scales, and resolutions is promising, and it could be useful in the generation of a model that could be defined as a hybrid. The correct geometry, accuracy, radiometry, and weight of the data models are hereby evaluated when comparing integrated processes and results from Terrestrial Laser Scanner (TLS), Mobile Mapping System (MMS), Unmanned Aerial Vehicle (UAV), and terrestrial photogrammetry, while using Total Station (TS) and Global Navigation Satellite System (GNSS) for topographic surveys. The entire analysis underlines the potentiality of the integration and fusion of different solutions and it is a crucial part of the ‘Torino 1911’ project whose main purpose is mapping and virtually reconstructing the 1911 Great Exhibition settled in the Valentino Park in Turin (Italy).

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An improved pixel-based water vapor tomography model

Annales Geophysicae ◽

10.5194/angeo-37-89-2019 ◽

2019 ◽

Vol 37 (1) ◽

pp. 89-100

Author(s):

Yibin Yao ◽

Linyang Xin ◽

Qingzhi Zhao

Keyword(s):

Water Vapor ◽

Three Dimensional ◽

Satellite System ◽

Reference Station ◽

Weather Forecasts ◽

Satellite Positioning ◽

Optimal Polynomial ◽

Improved Model ◽

Global Navigation Satellite ◽

Gnss Data

Abstract. As an innovative use of Global Navigation Satellite System (GNSS), the GNSS water vapor tomography technique shows great potential in monitoring three-dimensional water vapor variation. Most of the previous studies employ the pixel-based method, i.e., dividing the troposphere space into finite voxels and considering water vapor in each voxel as constant. However, this method cannot reflect the variations in voxels and breaks the continuity of the troposphere. Moreover, in the pixel-based method, each voxel needs a parameter to represent the water vapor density, which means that huge numbers of parameters are needed to represent the water vapor field when the interested area is large and/or the expected resolution is high. In order to overcome the abovementioned problems, in this study, we propose an improved pixel-based water vapor tomography model, which uses layered optimal polynomial functions obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF) by adaptive training for water vapor retrieval. Tomography experiments were carried out using the GNSS data collected from the Hong Kong Satellite Positioning Reference Station Network (SatRef) from 25 March to 25 April 2014 under different scenarios. The tomographic results are compared to the ECMWF data and validated by the radiosonde. Results show that the new model outperforms the traditional one by reducing the root-mean-square error (RMSE), and this improvement is more pronounced, at 5.88 % in voxels without the penetration of GNSS rays. The improved model also has advantages in more convenient expression.

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The sensitivity of GNSS measurements in Fennoscandia to distinct three-dimensional upper-mantle structures

Solid Earth Discussions ◽

10.5194/sed-5-2389-2013 ◽

2013 ◽

Vol 5 (2) ◽

pp. 2389-2418

Author(s):

H. Steffen ◽

P. Wu

Keyword(s):

Upper Mantle ◽

Gravity Data ◽

Three Dimensional ◽

High Sensitivity ◽

Element Model ◽

Satellite System ◽

Underlying Structure ◽

Gnss Measurements ◽

Global Navigation Satellite ◽

Three Dimensional Finite Element

Abstract. We present the sensitivity of Global Navigation Satellite System (GNSS) measurements at selected GNSS stations used both in the EUREF Permanent Network as well as in the BIFROST project to distinct areas in a laterally heterogeneous upper mantle beneath Fennoscandia. We therefore use a three-dimensional finite element model for glacial isostatic adjustment (GIA) calculations. The underlying structure is based on the S20A seismic tomography model, whose shear-wave velocities have been transformed into a viscosity structure of the upper mantle. Lower mantle is not investigated as previous results showed negligible sensitivity of Fennoscandian GIA data to it. We subdivide the upper mantle in four layers with lateral viscosity structure. Areas with similar viscosity within a layer are combined to larger blocks. Further subdivision is made into areas inside and outside the formerly glaciated areas. This leads to about 20 differently shaped areas per layer. We then calculate the sensitivity kernels at 10 selected GNSS stations for all blocks in comparison to a well-fitting one-dimensional GIA model. We find that GNSS stations are most sensitive to mantle viscosity in the near surrounding of the station, i.e. in the nearest about 250 km, and only within the formerly glaciated area. This area can be enlarged up to 800 km when velocities of stations in the uplift center are investigated. There is no indication of sufficiently high sensitivity of all investigated GNSS stations to regions outside the glaciated area. We also note that in the first mantle layer (70–250 km depth) below the lithosphere, there is only small sensitivity to parts along the Norwegian coast. Most prominent features in the Fennoscandian upper mantle may be detected in the second (250–450 km depth) and third layer (450–550 km depth). In future investigations on the lateral viscosity structure using GNSS measurements one should only consider GNSS stations within the area of former glaciation. They can be further grouped to address certain areas. In a combination with other GIA data, e.g. relative sea-level and gravity data, it is then highly recommended to assign more weight on those GNSS results with high sensitivity in order to determine the viscosity of a certain region.

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Assessment of global navigation satellite system (GNSS) radio occultation refractivity under heavy precipitation

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-11697-2018 ◽

2018 ◽

Vol 18 (16) ◽

pp. 11697-11708 ◽

Cited By ~ 7

Author(s):

Ramon Padullés ◽

Estel Cardellach ◽

Kuo-Nung Wang ◽

Chi O. Ao ◽

F. Joseph Turk ◽

...

Keyword(s):

Radio Occultation ◽

Three Dimensional ◽

Heavy Precipitation ◽

Satellite System ◽

Specific Humidity ◽

Positive Bias ◽

Actual Measurement ◽

Excess Phase ◽

Global Navigation Satellite ◽

Ray Paths

Abstract. A positive bias at heights between 3 and 8 km has been observed when comparing the radio-occultation (RO)-retrieved refractivity with that of meteorological analyses and reanalyses in cases where heavy precipitation is present. The effect of precipitation in RO retrievals has been investigated as a potential cause of the bias, using precipitation measurements interpolated into the actual three-dimensional RO ray paths to calculate the excess phase induced by precipitation. The study consisted of comparing the retrievals when such extra delay is removed from the actual measurement and when it is not. The results show how precipitation itself is not the cause of the positive bias. Instead, we show that the positive bias is linked to high specific-humidity conditions regardless of precipitation. This study also shows a regional dependence of the bias. Furthermore, different analyses and reanalyses show a disagreement under high specific-humidity conditions and, in consequence, heavy precipitation.

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Three-dimensional morphology of equatorial plasma bubbles deduced from measurements onboard CHAMP

Annales Geophysicae ◽

10.5194/angeo-33-129-2015 ◽

2015 ◽

Vol 33 (1) ◽

pp. 129-135 ◽

Cited By ~ 6

Author(s):

J. Park ◽

H. Lühr ◽

M. Noja

Keyword(s):

Three Dimensional ◽

Satellite System ◽

Low Earth Orbit ◽

Electron Content ◽

Total Electron ◽

Plasma Bubbles ◽

Equatorial Plasma Bubbles ◽

Global Navigation Satellite ◽

Plasma Depletion

Abstract. Total electron content (TEC) between Low-Earth-Orbit (LEO) satellites and the Global Navigation Satellite System (GNSS) satellites can be used to constrain the three-dimensional morphology of equatorial plasma bubbles (EPBs). In this study we investigate TEC measured onboard the Challenging Minisatellite Payload (CHAMP) from 2001 to 2005. We only use TEC data obtained when CHAMP passed through EPBs: that is, when in situ plasma density measurements at CHAMP altitude also show EPB signatures. The observed TEC gradient along the CHAMP track is strongest when the corresponding GNSS satellite is located equatorward and westward of CHAMP with elevation angles of about 40–60°. These elevation and azimuth angles are in agreement with the angles expected from the morphology of the plasma depletion shell proposed by Kil et al.(2009).

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Using Geomatic Techniques to Estimate Volume–Area Relationships of Watering Ponds

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi10080502 ◽

2021 ◽

Vol 10 (8) ◽

pp. 502

Author(s):

Ubaldo Marín-Comitre ◽

Álvaro Gómez-Gutiérrez ◽

Francisco Lavado-Contador ◽

Manuel Sánchez-Fernández ◽

Alberto Alfonso-Torreño

Keyword(s):

Storage Capacity ◽

Laser Scanner ◽

Satellite System ◽

Volume Estimation ◽

Quadratic Functions ◽

Average Error ◽

Power Relationship ◽

Hydrological Simulation ◽

Stereo Photogrammetry ◽

Global Navigation Satellite

Watering ponds represent an important part of the hydrological resources in some water-limited environments. Knowledge about their storage capacity and geometrical characteristics is crucial for a better understanding and management of water resources in the context of climate change. In this study, the suitability of different geomatic approaches to model watering pond geometry and estimate pond-specific and generalized volume–area–height (V–A–h) relationships was tested. Terrestrial structure-from-motion and multi-view-stereo photogrammetry (SfM-MVS), terrestrial laser scanner (TLS), laser-imaging detection and ranging (LIDAR), and aerial SfM-MVS were tested for the emerged terrain, while the global navigation satellite system (GNSS) was used to survey the submerged terrain and to test the resulting digital elevation models (DEMs). The combined use of terrestrial SfM-MVS and GNSS produced accurate DEMs of the ponds that resulted in an average error of 1.19% in the maximum volume estimation, comparable to that obtained by the TLS+GNSS approach (3.27%). From these DEMs, power and quadratic functions were used to express pond-specific and generalized V–A–h relationships and checked for accuracy. The results revealed that quadratic functions fit the data particularly well (R2 ≥ 0.995 and NRMSE < 2.25%) and can therefore be reliably used as simple geometric models of watering ponds in hydrological simulation studies. Finally, a generalized V–A power relationship was obtained. This relationship may be a valuable tool to estimate the storage capacity of other watering ponds in comparable areas in a context of data scarcity.

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