Journal articles: 'High-precision levelling'

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Jiang, Z., M. Becker, P. Jousset, A. Coulomb, L. Tisserand, P. Boulanger, D. Lequin, F. Lhermitte, J. L. Houillon, and F. Dupont. "High precision levelling supporting the International Comparison of Absolute Gravimeters." Metrologia 49, no. 1 (November 17, 2011): 41–48. http://dx.doi.org/10.1088/0026-1394/49/1/007.

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Boardman, J. C. "HIGH PRECISION LEVELLING OF MOTORWAYS. BY LOW LEVEL HELICOPTER SURVEY." Photogrammetric Record 14, no. 84 (October 1994): 925–42. http://dx.doi.org/10.1111/j.1477-9730.1994.tb00294.x.

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Ustavich, G. A., A. V. Nikonov, V. G. Salnikov, N. M. Ryabova, and A. S. Gorilko. "The technique of the III and IV classes levelling performed with trigonometric method." Geodesy and Cartography 949, no. 7 (August 20, 2019): 2–11. http://dx.doi.org/10.22389/0016-7126-2019-949-7-2-11.

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The III and IV classes leveling are applied in the Russian Federation for extension of height networks, at creating elevation control for building and large-scale surveying. The actual state levelling specification foresees applying the only geometric levelling technique. The geometric leveling performed in hilly and uneven terrain is difficult. Total stations of high precision increase the accuracy of height differences between two points by leap-frog trigonometric leveling. Using high precision total station and fulfillment of methodological requirements made it possible to perform trigonometric levelling of the III and IV classes. The developed methodology includes leveling with length of the sighting beam up to 250 m, as well as for the purpose of additional control, to use the vertical basis of a known length as a target sight. The implementation of trigonometric levelling makes the surveying of hilly and uneven area easier, and makes the beam of sight longer, increasing the productivity of work.

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Sevil, Jorge, Alfonso Benito‐Calvo, and Francisco Gutiérrez. "Sinkhole subsidence monitoring combining terrestrial laser scanner and high‐precision levelling." Earth Surface Processes and Landforms 46, no. 8 (March 31, 2021): 1431–44. http://dx.doi.org/10.1002/esp.5112.

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Volkov, Victor, and Nikita Volkov. "Use of the program and goal-oriented approach to observe the vertical displacements of the earth’s surface in Russia." E3S Web of Conferences 91 (2019): 07023. http://dx.doi.org/10.1051/e3sconf/20199107023.

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The paper considers the problematic issues of the special aspects of solution of the problems of modern geodynamics and technogenic geomechanics in oil and gas fields based on the results of re-levelling. The disadvantages and fundamental errors traditionally made by mining and land surveyors in organizing and performing re-levelling on the territories of oil and gas fields are given. The results of high precision levelling, obtained on the territory of an oil and gas field using the program and goal-oriented approach for its formulation, are presented. The representativeness and sufficient accuracy of obtaining the results of re-levelling allowed us to establish significant speeds of geodynamic and technogenic displacements of the earth’s surface (0.4 - 3.6 mm/year) in the shortest time possible with high economic efficiency.

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Badellas, A., and P. Savaidis. "High precision geodetic levelling for monitoring floor settlements in a spinning mill." Australian Surveyor 34, no. 5 (March 1989): 472–81. http://dx.doi.org/10.1080/00050326.1989.10438559.

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Xiao, Jiang, and Zhou Yan Yu. "The Research on Applying High Precision Ultrasonic Ranging in the Auto-Levelling System of Paver." Advanced Materials Research 443-444 (January 2012): 3–8. http://dx.doi.org/10.4028/www.scientific.net/amr.443-444.3.

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Paver can finish paving, ramming and pressing in a time, with certain density, thickness, width. It is suitable for various grades of highway, airport and road construction. The auto-levelling system, as an important part of paver, makes paver simple operation, safe and reliable, greatly reduce the loss of raw material and manpower, and the control accuracy directly influences the quality of paving flatness. The problems faced of auto-levelling system are introduced firstly. Secondly, ultrasonic sensor range finder technology at home and abroad and the present situation and basic principle, characteristics of ultrasonic sensor are clarified. Third,the range affecting factors of the ranging accuracy are found and appropriate method is put forward to compensating and correcting. Eventually, the method applied in the CPLD EPM570T100C5N, based on the C8051F040 singlechip , ultrasonic ranging circuit are formed. This paper illustrates the hardware and software design of every circuit module.

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Caputo, R., A. Pellegrinelli, C. Bignami, A. Bondesan, A. Mantovani, S. Stramondo, and P. Russo. "High-precision levelling, DInSAR and geomorphological effects in the Emilia 2012 epicentral area." Geomorphology 235 (April 2015): 106–17. http://dx.doi.org/10.1016/j.geomorph.2015.02.002.

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Wang, De Bao, Yong Xiang Liu, and Wen Jing Yang. "Establishment of High Precision Horizontal and Vertical Control Network in Zoucheng City." Advanced Materials Research 864-867 (December 2013): 2787–91. http://dx.doi.org/10.4028/www.scientific.net/amr.864-867.2787.

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The paper uses D level, E level and the level of GPS control network establishment satellite space geodetic network in Zoucheng city, through the baseline calculating, classic adjustment of free network, three-dimensional unconstrained adjustment and two-dimensional constraint adjustment to get the WGS-84 three dimensional coordinates and 1980 xi 'an horizontal coordinates of control points; then using the fourth-order levelling connection survey all D-level and part E-level control points to build vertical control network, for the remaining GPS control points we utilize quadric function method using GPS elevation fitting given its elevation seek to obtain three-dimensional coordinates of all the basic control points.

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Hirt, Christian, and Jakob Flury. "Astronomical-topographic levelling using high-precision astrogeodetic vertical deflections and digital terrain model data." Journal of Geodesy 82, no. 4-5 (July 18, 2007): 231–48. http://dx.doi.org/10.1007/s00190-007-0173-x.

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Popadyev, V. V., and D. A. Kuliev. "Application of global geopotential models to high-precesion levelling processing." Geodesy and Cartography 926, no. 8 (September 20, 2017): 2–9. http://dx.doi.org/10.22389/0016-7126-2017-926-8-2-9.

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The article studies the properties of the high-degree gravity field model EGM-2008 in the calculation of integral characteristics at large distances several times greater than the spatial resolution of the model. As an example of an indirect evaluation of a high-degree model, a gravimetric correction was computed into the sum of the measured elevations along the line of the high-precision I class leveling of the Krasnovodsk – Chardzhou line located in Turkmenistan. Using the calculator ICGEM, the Bouguer anomalies were calculated at each point of the line, then the attraction of the Bouguer layer (used heights are from catalog) excluded for the transition to free-air anomalies. In parallel, for a direct evaluation of the model, a regular grid of Bouguer anomalies with a step of 2 angular minutes within line area was also obtained, which were then compared with the anomalies from the gravity map J-40 of scale 1

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Borghi, Alessandra, Riccardo Barzaghi, Omar Al-Bayari, and Suhail Al Madani. "Centimeter Precision Geoid Model for Jeddah Region (Saudi Arabia)." Remote Sensing 12, no. 12 (June 26, 2020): 2066. http://dx.doi.org/10.3390/rs12122066.

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In 2014, the Jeddah Municipality made a call for an estimate of a centimetric precision geoid model to be used for engineering and surveying applications, because the regional geoid model available at that time did not reach a sufficient precision. A project was set up to this end and dedicated sets of gravity and Global Positioning System (GPS)/levelling data were acquired in the framework of this project. In this paper, a thorough analysis of these newly acquired data and of the last available Global Gravity Field Models (GGMs) has been done in order to obtain a geoid undulation estimate with the prescribed precision. In the framework of the Remove–Compute–Restore (RCR) approach, the collocation method was used to obtain the height anomaly estimation that was then converted to geoid undulation. The remove and restore steps of the RCR approach were based on GGMs, derived from the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) and Gravity Recovery and Climate Experiment (GRACE) dedicated gravity satellite missions, which were used to improve the long wavelength components of the Earth’s gravity field. Furthermore, two different quasi-geoid collocation estimates were computed, based on gravity data only and on gravity plus GPS/levelling data (the so-called hybrid estimate). The best solutions were obtained with the hybrid geoid estimate. This was tested by comparison with an independent set of GPS/levelling geoid undulations that were not included in the computed solutions. By these tests, the precision of the hybrid geoid is estimated to be 3.7 cm. This precision proved to be better, by a factor of two, than the corresponding one estimated from the pure gravimetric geoid. This project has been also useful to verify the importance and reliability of GGMs developed from the last satellite gravity missions (GOCE and GRACE) that have significantly improved our knowledge of the long wavelength components of the Earth’s gravity field, especially in areas with poor coverage of terrestrial gravity data. In fact, the geoid models based on satellite-only GGMs proved to have a better performance, despite the lower spatial resolution with respect to high-resolution models (i.e., Earth Gravitational Model 2008 (EGM2008)).

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Ketelaar, Gini, Hermann Bähr, Shizhuo Liu, Harry Piening, Wim van der Veen, Ramon Hanssen, Freek van Leijen, Hans van der Marel, and Sami Samiei-Esfahany. "Integrated monitoring of subsidence due to hydrocarbon production: consolidating the foundation." Proceedings of the International Association of Hydrological Sciences 382 (April 22, 2020): 117–23. http://dx.doi.org/10.5194/piahs-382-117-2020.

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Abstract. This paper describes several geodetic studies that consolidate the reliability and precision of monitoring subsidence due to hydrocarbon production: the deployment of Integrated Geodetic Reference Stations (IGRS); the application of high resolution InSAR; the comparison of different GNSS processing methodologies; the implementation of an efficient InSAR stochastic model, and the framework of integrated geodetic processing (levelling, GNSS, InSAR). The advances that have been made are applicable for any other subsidence monitoring project.

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Zhang, Hongliang, Jianhua Yang, Min Chen, Tengchao Huang, and Lijun Miao. "Design and calibration of a rotating laser transmitter for fast and high-precision laser self-levelling system." Measurement 171 (February 2021): 108850. http://dx.doi.org/10.1016/j.measurement.2020.108850.

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Popovas, Darius. "ANALYSIS OF THE IMPACT OF CELESTIAL BODIES ON DIFFERENCES IN MEASURED HEIGHT / DANGAUS KŪNŲ ĮTAKOS IŠMATUOTAM AUKŠČIŲ SKIRTUMUI TYRIMAS / АНАЛИЗ ВЛИЯНИЯ НЕБЕСНЫХ ТЕЛ НА ИЗМЕРЕННУЮ РАЗНИЦУ ВЫСОТ." Geodesy and Cartography 37, no. 3 (November 1, 2011): 101–4. http://dx.doi.org/10.3846/13921541.2011.626256.

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Under the effect of celestial bodies, the deflection of vertical induces changes in the levelled height difference. Therefore, it is necessary to evaluate the produced effect on high-precision levelling data. The article analyses the dependency of lunisolar correction on the lunar phase and azimuth of the levelling line and correction rate of changes. The paper also revises formulas for calculating lunisolar correction derived from using tide generating potential. Santrauka Straipsnyje analizuojama vertikalės nuokrypio dėl dangaus kūnų įtaka išmatuotam aukščių skirtumui. Šią įtaką būtina įvertinti apdorojant precizinės niveliacijos matavimų duomenis. Įvertinta potvynio pataisos priklausomumas nuo Mėnulio fazių ir niveliacijos linijos azimuto bei pataisos kitimo greitis. Taikant potvynio potencialo išraišką, gautos patikslintos išmatuoto aukščių skirtumo vertinimo formulės. Резюме Под влиянием небесных тел отклонение вертикали вызывает изменения в разнице высот, полученной нивелированием. Необходимо оценить этот эффект в данных высокоточной нивеляции. Были проанали зированы зависимость лунно-солнечных поправок от лунных фаз, азимута линии нивеляций и скорости изменения поправки. Получены уточненные формулы для расчета лунно-солнечной поправки с использованием приливного потенциала.

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Jürgenson, Harli, Kristina Türk, and Jüri Randjärv. "DETERMINATION AND EVALUATION OF THE ESTONIAN FITTED GEOID MODEL EST-GEOID 2003 / ESTIJOS GEOIDO MODELIO EST-GEOID 2003 SUDARYMAS IR VERTINIMAS / СОЗДАНИЕ И ОЦЕНКА МОДЕЛИ ГЕОИДА ЭСТОНИИ EST-GEOID2003." Geodesy and Cartography 37, no. 1 (April 15, 2011): 15–21. http://dx.doi.org/10.3846/13921541.2011.558339.

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This paper focuses on issues related to the calculation of a high-precision fitted geoid model on Estonian territory. Model Est-Geoid2003 have been used in Estonia several years in geodesy and other applications. New data from precise levelling, new global models and terrestrial gravity data give plenty of possibilities for updates and accuracy evaluation. The model is based on a gravimetric geoid. From the gravimetric data gathered, a gravimetric geoid for Estonia was calculated as an approximately 3-km net using the FFT method. After including the new gravimetric data gathered, the gravimetric geoid no longer had any significant tilt relative to the height anomalies derived from GPS-levelling points. The standard deviation between the points was 2.7 cm. The surface of the calculated gravimetric geoid was fitted by high-precision GPS-levelling points. As a result, a height transformation model was determined to reflect the differences between the normal heights of BK77 and the ellipsoidal heights of EUREF-EST97 on Estonian territory. The model was originally called Est-Geoid2003 and is part of the official national geodetic system in Estonia. The model is updated and evaluated here using precise GPS-levelling points obtained from different measurement campaigns. In 2008–2010 the preliminary results from the latest precise levelling sessions became available, leading to a significant increase in the number of precise GPS-levelling points. Both networks are part of the Estonian integrated geodetic network. Using very precise levelling connections from new levelling lines, normal heights of several RGP points were calculated additionally. Misclosure of 300 km polygons are less than 2–3 mm normally. Ealier all precisely levelled RGP points were included into fitting points. Now many new points are available for fitting and independent evaluation. However, the use of several benchmarks for the same RGP point sometimes results in a 1–2 cm difference in normal height. This reveals problems with the stability of older wall benchmarks, which are widely used in Estonia. Even we recognized, that 0.5 cm fitted geoid model is not achievable using wall benchmarks. New evaluation of the model Est-Geoid2003 is introduced in the light of preliminary data from new precise levelling. Model accuracy is recognised about 1.2 cm as rms. Santrauka Akcentuojami klausimai, susiję su tiksliausio Estijos geoido modelio skaičiavimu. Šis modelis Estijoje geodezijoje ir kitose mokslo bei technikos šakose taikomas nuo 2003 metų. Nauji precizinės niveliacijos duomenys, nauji globalieji geopotencialo modeliai ir žemyno gravimetriniai duomenys – prielaidos geoido modeliui atnaujinti ir jo tikslumui įvertinti. Modelio pagrindas – gravimetrinis geoidas. Pagal surinktus gravimetrinius duomenis Estijos geoidas buvo apskaičiuotas greitųjų Furjė tranformacijų (FFT) metodu, sukuriant apie 3 km akių tinklą. Įtraukus naujuosius gravimetrinius duomenis, gravimetrinis geoidas daugiau nebeturi aukščių anomalijų. Vidutinė kvadratinė paklaida – 2,7 cm. Apskaičiuoto gravimetrinio geoido paviršius susietas su aukščių sistema pagal GPS niveliacijos taškus. 2008–2010 m. gavus precizinės niveliacijos duomenis, žymiai padidėjo GPS niveliacijos taškų skaičius bei jų tikslumas, nes precizinės niveliacijos poligonų iki 300 km nesąryšiai gauti mažesni nei 2–3 mm. Įvertinus naujo Estijos geoido modelio tikslumą nustatyta 1,2 cm vidutinė kvadratinė paklaida. Резюме Акцентируются вопросы, касающиеся вычисления точной модели геоида Эстонии. Эта модель применяется в Эстонии с 2003 г. в геодезии и других отраслях науки и техники. Новые данные высокоточной нивеляции, новые глобальные модели геопотенциала, а также гравиметрические данные создают предпосылки для обновления модели геоида и оценки его точности. Модель основана на гравиметрическом геоиде. Модель геоида Эстонии была вычислена быстрым методом Фурье с использованием всех гравиметрических данных и созданием сети 3×3 км. После использования новых гравиметрических данных в геоиде не оказалось значительного превышения высот по сравнению с точками, измеренными методом GPS. Среднеквадратическая погрешность составила 2,7 см. Вычисленная модель геоида была соединена с системой высот по точкам GPSнивелирования. Благодаря новым данным по высокоточной нивеляции, полученным в 2008–2010 гг., значительно увеличилось количество точек GPSнивелирования и тем самым увеличилась точность геоида, так как невязки полигонов нивелирования составляют всего 2–3 мм. Оценив точность нового геоида Эстонии, выявлено среднеквадратическое отклонение в 1,2 см.

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Galindo-Zaldívar, Jesus, Maria Jesus Borque, Antonio Pedrera, Carlos Marín-Lechado, Antonio José Gil, and Angel Carlos López-Garrido. "Deformation behaviour of the low-rate active Balanegra Fault Zone from high-precision levelling (Betic Cordillera, SE Spain)." Journal of Geodynamics 71 (November 2013): 43–51. http://dx.doi.org/10.1016/j.jog.2013.07.003.

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Miao, Qingfeng, José M. Gonçalves, Ruiping Li, Diana Gonçalves, Tiago Levita, and Haibin Shi. "Assessment of Precise Land Levelling on Surface Irrigation Development. Impacts on Maize Water Productivity and Economics." Sustainability 13, no. 3 (January 23, 2021): 1191. http://dx.doi.org/10.3390/su13031191.

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The new technologies of surface irrigation require the adoption of effective Laser-controlled precision land levelling (PLL) to reach the high irrigation performance standards, with significant benefits on water saving, salinity control, crop productivity, and farmer’s income. This study aimed to assess the performance and the impacts of PLL on surface irrigation systems, focusing the maize crop on the irrigation districts Hetao (China) and Lower-Mondego (Portugal). The experimental study at field scale assessed the PLL and evaluated the on-farm irrigation under precise levelled fields and well management practices. PLL operators have been inquired to improve the knowledge about hiring services. The design of surface irrigation scenarios allowed to explain the effects of field size and slope on irrigation and land levelling performance. The best practice to manage the PLL maintenance is an important issue to guarantee a high effectiveness of irrigation performance. The optimization of PLL appeals the application of best soil tillage practices and the monitoring of soil surface elevations with newest information technologies. Efficient operational guidelines to support the PLL planning, schedule, and operation, well trained operators and carefully adjusted equipment, are key factors to the improvement.

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Kobe, Martin, Gerald Gabriel, Adelheid Weise, and Detlef Vogel. "Time-lapse gravity and levelling surveys reveal mass loss and ongoing subsidence in the urban subrosion-prone area of Bad Frankenhausen, Germany." Solid Earth 10, no. 3 (May 13, 2019): 599–619. http://dx.doi.org/10.5194/se-10-599-2019.

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Abstract. We present results of sophisticated, high-precision time-lapse gravity monitoring that was conducted over 4 years in Bad Frankenhausen (Germany). To our knowledge, this is the first successful attempt to monitor subrosion-induced mass changes in urban areas with repeated gravimetry. The method provides an approach to estimate the mass of dissolved rocks in the subsurface. Subrosion, i.e. leaching and transfer of soluble rocks, occurs worldwide. Mainly in urban areas, any resulting ground subsidence can cause severe damage, especially if catastrophic events, i.e. collapse sinkholes, occur. Monitoring strategies typically make use of established geodetic methods, such as levelling, and therefore focus on the associated deformation processes. In this study, we combine levelling and highly precise time-lapse gravity observations. Our investigation area is the urban area of Bad Frankenhausen in central Germany, which is prone to subrosion, as many subsidence and sinkhole features on the surface reveal. The city and the surrounding areas are underlain by soluble Permian deposits, which are continuously dissolved by meteoric water and groundwater in a strongly fractured environment. Between 2014 and 2018, a total of 17 high-precision time-lapse gravimetry and 18 levelling campaigns were carried out in quarterly intervals within a local monitoring network. This network covers historical sinkhole areas but also areas that are considered to be stable. Our results reveal ongoing subsidence of up to 30.4 mm a−1 locally, with distinct spatiotemporal variations. Furthermore, we observe a significant time-variable gravity decrease on the order of 8 µGal over 4 years at several measurement points. In the processing workflow, after the application of all required corrections and least squares adjustment to our gravity observations, a significant effect of varying soil water content on the adjusted gravity differences was figured out. Therefore, we place special focus on the correlation of these observations and the correction of the adjusted gravity differences for soil water variations using the Global Land Data Assimilation System (GLDAS) Noah model to separate these effects from subrosion-induced gravity changes. Our investigations demonstrate the feasibility of high-precision time-lapse gravity monitoring in urban areas for sinkhole investigations. Although the observed rates of gravity decrease of 1–2 µGal a−1 are small, we suggest that it is significantly associated with subterranean mass loss due to subrosion processes. We discuss limitations and implications of our approach, as well as give a first quantitative estimation of mass transfer at different depths and for different densities of dissolved rocks.

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Salnikov, Valerij G. "IMPROVEMENT OF HIGH-PRECISION LEVELLING METHOD BY DIGITAL LEVELS IN THE CONDITION OF NON-SUFFICIENT LIGHT INTENSITY OF LINED ROD." Vestnik SSUGT (Siberian State University of Geosystems and Technologies) 25, no. 3 (2020): 63–71. http://dx.doi.org/10.33764/2411-1759-2020-25-3-63-71.

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The performing of high-precision geometric leveling by short beams with the purpose of control for the process of building and exploitation of engineering structures and industrial equipment is carried out with visual reading levels or digital levels in case there are a lot of disturbance effects, the basic of which are the vibrations of some equipment in operation, rapid temperature changes, and also non-sufficient and irregular light intensity of bar-code or lined rods. The purpose of the article is the improvement of high-precision leveling method performance by digital levels in the condition of insufficient light intensity of bar-code rods. The article considers the influence of insufficient light intensity of bar-code rods on the leveling station work by digital levels. Due to irregular and insufficient light intensity of the rod the receiver of the digital level does not allow to read distinctly the bar-code and to perform its processing and output to the indication unit in metric system. That’s why for accurate measurement on the station the light intensity of the rods should be sufficient, nearly similar and regular. The article gives the results of using the rod, equipped with light-emitting diodes to provide its sufficient and regular lighting.

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Ardha, Mohammad, Argo Galih Suhadha, Atriyon Julzarika, Fajar Yulianto, Dipo Yudhatama, and Rofifatuz Zulfa Darwista. "Utilization of Sentinel-1 satellite imagery data to support land subsidence analysis in DKI Jakarta, Indonesia." Journal of Degraded and Mining Lands Management 8, no. 2 (December 31, 2020): 2587–93. http://dx.doi.org/10.15243/jdmlm.2021.082.2587.

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Land subsidence had been a significant problem in DKI Jakarta and Semarang, with at least 20 kilometres of roads affected. Repairing them will require at least US $ 1 million per kilometre. Land subsidence monitoring has been carried out using terrestrial methods (GPS and levelling), which are believed to have a high degree of accuracy. The high accuracy of the terrestrial method results in a lack of precision over a large area. On the other hand, remote sensing technology as a non-terrestrial method has developed to monitor land subsidence which can produce high precision over a large area. This study aimed to test the Sentinel-1 satellite data using the Differential Interferometric Synthetic Aperture Radar (DInSAR) method in monitoring land subsidence in DKI Jakarta. DInSAR is a method in Remote Sensing that utilizes radar sensors to analyze the phase differences of a SAR data pair that have different times of capture and have been catalogued to obtain displacement along the area of collection. The results showed that the North Jakarta area experienced the highest land subsidence in the entire Jakarta area. The annual average rate from 2017-2019 is 3.4 cm. The value of 3.4 cm is the average value of all samples in the North Jakarta area. The second area where high land subsidence is West Jakarta, where the maximum amount value of subsidence is 2.8 cm. The accuracy-test results with the MONAS test point showed that the difference between field data and DInSAR results was ± 6.5 cm. The results of this research indicate that the DInSAR method is quite capable of describing land subsidence in the DKI Jakarta area with a relatively good level of precision.

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Cheloni, D., N. D’Agostino, E. D’Anastasio, and G. Selvaggi. "Reassessment of the source of the 1976 Friuli, NE Italy, earthquake sequence from the joint inversion of high-precision levelling and triangulation data." Geophysical Journal International 190, no. 2 (July 3, 2012): 1279–94. http://dx.doi.org/10.1111/j.1365-246x.2012.05561.x.

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Bitelli, Gabriele, Giorgia Gatta, Valentina Alena Girelli, Luca Vittuari, and Antonio Zanutta. "Integrated Methodologies for the 3D Survey and the Structural Monitoring of Industrial Archaeology: The Case of the Casalecchio di Reno Sluice, Italy." International Journal of Geophysics 2011 (2011): 1–8. http://dx.doi.org/10.1155/2011/874347.

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The paper presents an example of integrated surveying and monitoring activities for the control of an ancient structure, the Casalecchio di Reno sluice, located near Bologna, Italy. Several geomatic techniques were applied (classical topography, high-precision spirit levelling, terrestrial laser scanning, digital close-range photogrammetry, and thermal imagery). All these measurements were put together in a unique reference system and used in order to study the stability and the movements of the structure over the period of time observed. Moreover, the metrical investigations allowed the creation of a 3D model of the structure, and the comparison between two situations, before and after the serious damages suffered by the sluice during the winter season 2008-2009. Along with the detailed investigations performed on individual portions of the structure, an analysis of the whole sluice, carried out at a regional scale, was done via the use of aerial photogrammetry, using both recently acquired images and historical photogrammetric coverage. The measurements were carried out as part of a major consolidation and restoration activity, carried out by the “Consorzio della Chiusa di Casalecchio e del Canale di Reno”.

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Mill, Tarvo, Artu Ellmann, Martti Kiisa, Juhan Idnurm, Siim Idnurm, Milan Horemuz, and Andrus Aavik. "Geodetic monitoring of bridge deformations occurring during static load testing." BALTIC JOURNAL OF ROAD AND BRIDGE ENGINEERING 10, no. 1 (March 10, 2015): 17–27. http://dx.doi.org/10.3846/bjrbe.2015.03.

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Terrestrial laser scanning technology has developed rapidly in recent years and has been used in various applications but mainly in the surveying of different buildings and historical monuments. The use for terrestrial laser scanning data for deformation monitoring has earlier been tested although conventional surveying technologies are still more preferred. Since terrestrial laser scanners are capable of acquiring a large amount of highly detailed geometrical data from a surface it is of interest to study the metrological advantages of the terrestrial laser scanning technology for deformation monitoring of structures. The main intention of this study is to test the applicability of terrestrial laser scanning technology for determining range and spatial distribution of deformations during bridge load tests. The study presents results of deformation monitoring proceeded during a unique bridge load test. A special monitoring methodology was developed and applied at a static load test of a reinforced concrete cantilever bridge built in 1953. Static loads with the max force of up to 1961 kN (200 t) were applied onto an area of 12 m² in the central part of one of the main beams; the collapse of the bridge was expected due to such an extreme load. Although the study identified occurrence of many cracks in the main beams and significant vertical deformations, both deflection (–4.2 cm) and rising (+2.5 cm), the bridge did not collapse. The terrestrial laser scanning monitoring results were verified by high-precision levelling. The study results confirmed that the TLS accuracy can reach ±2.8 mm at 95% confidence level.

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Cheloni, D., R. Giuliani, E. D'Anastasio, S. Atzori, R. J. Walters, L. Bonci, N. D'Agostino, et al. "Coseismic and post-seismic slip of the 2009 L'Aquila (central Italy) MW 6.3 earthquake and implications for seismic potential along the Campotosto fault from joint inversion of high-precision levelling, InSAR and GPS data." Tectonophysics 622 (May 2014): 168–85. http://dx.doi.org/10.1016/j.tecto.2014.03.009.

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Jia, Hongguo, Hao Zhang, Wenjing Ren, and Bin Yan. "Deformation Monitoring of Landslide Based on Adapted Distributed Scatter Interferometric Synthetic Aperture Radar." Abstracts of the ICA 1 (July 15, 2019): 1. http://dx.doi.org/10.5194/ica-abs-1-149-2019.

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Abstract. Landslide is a typical geological disaster, which may be caused by long-term heavy rainfall, human activities, and earthquakes. Landslides are extremely destructive so as to result in a serious threat to local public security. The deformation monitoring of landslide can provide an early warning and disaster prevention and mitigation measures. At present, the traditional landslide monitoring methods include absolute deformation monitoring, e.g. GPS surveying, total station and levelling， and relative deformation monitoring, e.g. displacement meter, crack meter and fiber optical sensors. Although these methods by ground measuring have the advantage of high precision, they can monitor only a limited number of points on the landslide body and need a large amount of field work and the high cost.In order to improve the accuracy of potential hazard of landslide detection and achieve deformation information for landslide areas, we proposed an adaptive distributed scatterer interferometric Radar method (ADS-InSAR), which can automatically adjust the detection threshold according to the spatiotemporal coherence of different distributed scatterer (DS) so as to improve the density and reliability of spatial distribution of DS. After the time series network modelling and deformation solution of the ADS are achieved, the displacement deformation details of the landslide area are extracted. In this paper, the experimental area of Shuibuya Town, Enshi Prefecture, Hubei Province, China was selected and the Sentinal-1A radar images data were used from March 5, 2016 to April 5, 2017. The ADS-InSAR method was utilized to obtain the subsidence time series of the region. The deformation time series is finally analysed combined with hydro meteorological and related data. Experimental results indicated that the method proposed in this paper can effectively improve the density of DS distribution and can successfully detect the existing ancient landslide group and find multiple suspected landslide areas for disaster warning, and has high reliability and accuracy in landslide disaster prevention and mitigation.

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Spaner, D., D. B. McKenzie, A. G. Todd, A. Simms, M. MacPherson, and E. F. Woodrow. "Six years of adaptive and on-farm spring cereal research in Newfoundland." Canadian Journal of Plant Science 80, no. 1 (January 1, 2000): 205–16. http://dx.doi.org/10.4141/p99-076.

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Livestock farmers in Newfoundland use most available land for forages. The local production of feed grains is negligible and expensive imported feed accounts for almost one half of farm operating expenses. Here, our objectives were to develop basic agronomic principles of mechanized spring grain production and to demonstrate grain production techniques to the Newfoundland farming community. Barley seeding date trials were conducted at five environments in eastern and western Newfoundland between 1996 and 1998. The relationship between soil pH and barley grain yield was explored through grid soil and yield sampling in two large fields in both 1997 and 1998. Between 1993 and 1998 over 20 livestock farmers throughout Newfoundland cooperated with the Newfoundland Grain Project, growing and comparing varieties of barley (Hordeum vulgare L.), spring wheat (Triticum aestivum L.) and oats (Avena sativa L.) on their farms. Late seeding of barley in the spring/summer resulted in linear grain yield reductions. A levelling off of yield response did not occur at greater cumulated growing degree days, possibly because optimum accumulation for maximum barley yield potential does not occur in Newfoundland. Resistant regression lines, describing the relationship between soil pH and grain yield were developed for two barley varieties, indicated that Sterling reached a yield plateau around a soil pH 6 in 1998, while Chapais reached a yield plateau at soil pH 5.4 in 1997. Barley is well adapted to Newfoundland growing conditions, normally providing a high-yielding, mature grain of good feeding quality. Farmers collaborating with the project were generally impressed with the potential of growing barley for grain and some are now regularly doing so. Key words: Seeding date; barley; wheat; oats; precision farming research

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Muszyński, Zbigniew, and Jarosław Rybak. "Evaluation of Terrestrial Laser Scanner Accuracy in the Control of Hydrotechnical Structures." Studia Geotechnica et Mechanica 39, no. 4 (December 1, 2017): 45–57. http://dx.doi.org/10.1515/sgem-2017-0036.

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Abstract In many cases of monitoring or load testing of hydrotechnical structures, the measurement results obtained from dial gauges may be affected by random or systematic errors resulting from the instability of the reference beam. For example, the measurement of wall displacement or pile settlement may be increased (or decreased) by displacements of the reference beam due to ground movement. The application of surveying methods such as high-precision levelling, motorized tacheometry or even terrestrial laser scanning makes it possible to provide an independent reference measurement free from systematic errors. It is very important in the case of walls and piles embedded in the rivers, where the construction of reference structure is even more difficult than usually. Construction of an independent reference system is also complicated when horizontal testing of sheet piles or diaphragm walls are considered. In this case, any underestimation of the horizontal displacement of an anchored or strutted construction leads to an understated value of the strut’s load. These measurements are even more important during modernization works and repairs of the hydrotechnical structures. The purpose of this paper is to discuss the possibilities of using modern measurement methods for monitoring of horizontal displacements of an excavation wall. The methods under scrutiny (motorized tacheometry and terrestrial laser scanning) have been compared to classical techniques and described in the context of their practical use on the example hydrotechnical structure. This structure was a temporary cofferdam made from sheet pile wall. The research continuously conducted at Wroclaw University of Science and Technology made it possible to collect and summarize measurement results and practical experience. This paper identifies advantages and disadvantages of both analysed methods and presents a comparison of obtained measurement results of horizontal displacements. In conclusion, some recommendations have been formulated, which are relevant from the point of view of engineering practice.

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Alimonti, Claudio, Valerio Baiocchi, Giorgia Bonanotte, and Gábor Molnár. "Roman Aqueduct Flow Estimation Using Geomatic Measurement." ISPRS International Journal of Geo-Information 10, no. 6 (May 25, 2021): 360. http://dx.doi.org/10.3390/ijgi10060360.

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The aqueducts built by the ancient Romans are among the most impressive evidence of their engineering skills. The water inside the aqueducts was transported for kilometers, exploiting only the slight but constant differences in altitude throughout the route. To keep the differences in height constant, the aqueducts could proceed underground or aboveground on well-known arched structures that supported lead, ceramic or stone pipes. In order to reconstruct the characteristics of these structures, it is necessary to carry out an accurate survey of the orthometric heights, and therefore the most suitable technology is geometric levelling. In this case, however, it is not applicable, and therefore here we propose an alternative methodology. The final goal of this work was to estimate the flow of some sectors of these aqueducts preserved in the area south of the city of Rome. This has two main purposes: The first is to reconstruct the flow rate of these aqueducts for historical studies; the second is to check how much the orthometric heights have changed over the centuries, in order to reconstruct the movements from a geophysical and geodynamic point of view. The latter analysis will be developed in a following phase of this research. For this purpose, a high-precision geomatic survey was carried out in the area under study, partly retracing a survey already carried out in 1917 whose purpose and methodologies are not known. The area has been affected by a gradual subsidence over centuries, including since 1917. The observed sections of the aqueducts showed average inclinations, slightly lower than the 2 per thousand that is reported in the literature for similar aqueducts. The measurements carried out allowed the flow rate of the two specific aqueducts to be estimated more accurately, both as they were originally and in the presence of deposits that have accumulated during the years of use of the aqueducts. The reconstruction of the initial geometry will later be used as a reference to estimate how much the geodynamic deformations of the area have deformed the aqueducts themselves.

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Santillan, J. R., and M. Makinano-Santillan. "VERTICAL ACCURACY ASSESSMENT OF 30-M RESOLUTION ALOS, ASTER, AND SRTM GLOBAL DEMS OVER NORTHEASTERN MINDANAO, PHILIPPINES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B4 (June 13, 2016): 149–56. http://dx.doi.org/10.5194/isprsarchives-xli-b4-149-2016.

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The ALOS World 3D – 30 m (AW3D30), ASTER Global DEM Version 2 (GDEM2), and SRTM-30 m are Digital Elevation Models (DEMs) that have been made available to the general public free of charge. An important feature of these DEMs is their unprecedented horizontal resolution of 30-m and almost global coverage. The very recent release of these DEMs, particularly AW3D30 and SRTM- 30 m, calls for opportunities for the conduct of localized assessment of the DEM’s quality and accuracy to verify their suitability for a wide range of applications in hydrology, geomorphology, archaelogy, and many others. In this study, we conducted a vertical accuracy assessment of these DEMs by comparing the elevation of 274 control points scattered over various sites in northeastern Mindanao, Philippines. The elevations of these control points (referred to the Mean Sea Level, MSL) were obtained through 3rd order differential levelling using a high precision digital level, and their horizontal positions measured using a global positioning system (GPS) receiver. These control points are representative of five (5) land-cover classes namely brushland (45 points), built-up (32), cultivated areas (97), dense vegetation (74), and grassland (26). Results showed that AW3D30 has the lowest Root Mean Square Error (RMSE) of 5.68 m, followed by SRTM-30 m (RMSE = 8.28 m), and ASTER GDEM2 (RMSE = 11.98 m). While all the three DEMs overestimated the true ground elevations, the mean and standard deviations of the differences in elevations were found to be lower in AW3D30 compared to SRTM-30 m and ASTER GDEM2. The superiority of AW3D30 over the other two DEMS was also found to be consistent even under different landcover types, with AW3D30's RMSEs ranging from 4.29 m (built-up) to 6.75 m (dense vegetation). For SRTM-30 m, the RMSE ranges from 5.91 m (built-up) to 10.42 m (brushland); for ASTER GDEM2, the RMSE ranges from 9.27 m (brushland) to 14.88 m (dense vegetation). The results of the vertical accuracy assessment suggest that the AW3D30 is more accurate than SRTM-30 m and ASTER GDEM2, at least for the areas considered in this study. On the other hand, the tendencies of the three DEMs to overestimate true ground elevation can be considered an important finding that users of the DEMs in the Philippines should be aware of, and must be considered into decisions regarding use of these data products in various applications.

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Santillan, J. R., and M. Makinano-Santillan. "VERTICAL ACCURACY ASSESSMENT OF 30-M RESOLUTION ALOS, ASTER, AND SRTM GLOBAL DEMS OVER NORTHEASTERN MINDANAO, PHILIPPINES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B4 (June 13, 2016): 149–56. http://dx.doi.org/10.5194/isprs-archives-xli-b4-149-2016.

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The ALOS World 3D – 30 m (AW3D30), ASTER Global DEM Version 2 (GDEM2), and SRTM-30 m are Digital Elevation Models (DEMs) that have been made available to the general public free of charge. An important feature of these DEMs is their unprecedented horizontal resolution of 30-m and almost global coverage. The very recent release of these DEMs, particularly AW3D30 and SRTM- 30 m, calls for opportunities for the conduct of localized assessment of the DEM’s quality and accuracy to verify their suitability for a wide range of applications in hydrology, geomorphology, archaelogy, and many others. In this study, we conducted a vertical accuracy assessment of these DEMs by comparing the elevation of 274 control points scattered over various sites in northeastern Mindanao, Philippines. The elevations of these control points (referred to the Mean Sea Level, MSL) were obtained through 3rd order differential levelling using a high precision digital level, and their horizontal positions measured using a global positioning system (GPS) receiver. These control points are representative of five (5) land-cover classes namely brushland (45 points), built-up (32), cultivated areas (97), dense vegetation (74), and grassland (26). Results showed that AW3D30 has the lowest Root Mean Square Error (RMSE) of 5.68 m, followed by SRTM-30 m (RMSE = 8.28 m), and ASTER GDEM2 (RMSE = 11.98 m). While all the three DEMs overestimated the true ground elevations, the mean and standard deviations of the differences in elevations were found to be lower in AW3D30 compared to SRTM-30 m and ASTER GDEM2. The superiority of AW3D30 over the other two DEMS was also found to be consistent even under different landcover types, with AW3D30's RMSEs ranging from 4.29 m (built-up) to 6.75 m (dense vegetation). For SRTM-30 m, the RMSE ranges from 5.91 m (built-up) to 10.42 m (brushland); for ASTER GDEM2, the RMSE ranges from 9.27 m (brushland) to 14.88 m (dense vegetation). The results of the vertical accuracy assessment suggest that the AW3D30 is more accurate than SRTM-30 m and ASTER GDEM2, at least for the areas considered in this study. On the other hand, the tendencies of the three DEMs to overestimate true ground elevation can be considered an important finding that users of the DEMs in the Philippines should be aware of, and must be considered into decisions regarding use of these data products in various applications.

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de Lacy, M. Clara, M. Isabel Ramos, Antonio J. Gil, Óscar D. Franco, Antonio M. Herrera, Manuel Avilés, Alicia Domínguez, and Juan Carlos Chica. "Monitoring of vertical deformations by means high-precision geodetic levelling. Test case: The Arenoso dam (South of Spain)." Journal of Applied Geodesy 11, no. 1 (January 1, 2017). http://dx.doi.org/10.1515/jag-2016-0034.

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AbstractThe Arenoso reservoir is created by an embankment dam, with central clay core, slates and greywacke shoulders. This kind of engineering structure is subject of deformation due to factors such as changes of water level of the reservoir, seat structure, climate changes, etc. In general, dam monitoring involves measurements both outside (external shell) and inside the structure. A number of control points is established around the area of the dam and the measurements of the displacements of the control points take place at several epochs. In this study high-precision levelling techniques have been used to monitor the vertical deformations. In particular five high-precision levelling profiles were measured in five surveys: February and July 2008, March and July 2013 and August 2014. In this study the design, observations and results are presented. On the one hand the results put in evidence the precision of the observations that are always under 1-mm level. On the other hand these results indicate downstream (southeastward) motion of the thrust block center of the dam probably during the fall and winter. The subsidence reachs here the maximum with a value of −14 cm in 2014 (in respect of February 2008). The displacements observed at the berms of the dam exhibit a similar trend to the displacements observed at the crest but they are significantly smaller, as expected. The accumulative vertical displacements and the settlement index indicate the magnitude of the movements decrease in time, confirming the dam tends to stabilize.

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M.Salim, Sarmad Abdullah, and Sarhat Mustafa Adam. "Investigating the vertical displacement of Duhok embankment Dam: A 31- Years Case Study." Journal of Engineering Research 9, ICRIE (August 22, 2021). http://dx.doi.org/10.36909/jer.v9iicrie.11655.

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The paper studies the long-term settlement behaviour of more than 30-year of the Duhok dam. The dam uses as the major lake for water supply to the city of Duhok and nearby areas. High-precision levelling was used to measure the deformation of the dam to monitor vertical displacements. Five survey campaigns were conducted over 30-year duration: 1988, March 1990, June 1999, March 2017 and February 2019. Analysis of the results found that the highest downward displacement of roughly 20.4 cm was witnessed between 1988 and 2019 for a monitoring point (BM24) located centrally along the bank of the dam. On the other hand, the highest vertical movement of roughly 1.5 cm was estimated between 1990 and 2019 at the monitoring point (BM27) on the west side of the dam. The monitoring point (BM24) had the highest average absolute movement of about 6.0 mm (per year) over the 31 years. Detailed results and analyzes are presented in this article.

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"Appication of high precision levelling and photogrammetry to the detection of the movements of an architectonic complex produced by subsidence in the town of Bologna." International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts 24, no. 6 (December 1987): 241. http://dx.doi.org/10.1016/0148-9062(87)92471-5.

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Journal articles on the topic 'High-precision levelling'

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