Academic literature on the topic 'GNSS NRTK Quality control'
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Journal articles on the topic "GNSS NRTK Quality control"
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Bernstein, T., and V. Janssen. "Positional uncertainty of network RTK observations in a modern datum." Journal of Geodetic Science 11, no. 1 (January 1, 2021): 38–47. http://dx.doi.org/10.1515/jogs-2020-0116.
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Abstract The Geocentric Datum of Australia 2020 (GDA2020) is Australia’s new and much improved national datum. It is based on a single, nationwide least squares network adjustment that rigorously propagates uncertainty. This paper explores three options to include Network Real-Time Kinematic (NRTK) observations and their Positional Uncertainty (PU) in the survey control network of New South Wales (NSW) via the GDA2020 state adjustment. In the first option, PU is empirically estimated based on a dataset of more than 1,500 observations to obtain values that can be uniformly applied to all NRTK observations. In the second option, PU is calculated for each NRTK observation, based on the coordinate quality indicators provided by the Global Navigation Satellite System (GNSS) equipment. Both options continue to treat NRTK observations as point-based position solutions, resulting in poor correlation with surrounding survey control marks. The third option overcomes this issue by utilising the automatically computed GNSS baselines between NRTK observations and their Virtual Reference Station (VRS) to create a connected network that can be adjusted like a static GNSS network. Using a typical urban NRTK survey in Sydney as an example, it is shown that this method offers a rigorous computation of PU, while maintaining the quick and easy nature of NRTK positioning.
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Famiglietti, Nicola Angelo, Gianpaolo Cecere, Carmine Grasso, Antonino Memmolo, and Annamaria Vicari. "A Test on the Potential of a Low Cost Unmanned Aerial Vehicle RTK/PPK Solution for Precision Positioning." Sensors 21, no. 11 (June 4, 2021): 3882. http://dx.doi.org/10.3390/s21113882.
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This paper investigated the achievable accuracy from a low-cost RTK (Real Time Kinematic)/PPK (Post Processing Kinematic) GNSS (Global Navigation Satellite Systems) system installed on board a UAV (Unmanned Aerial Vehicle), employing three different types of GNSS Bases (Alloy, RS2 and RING) working in PPK mode. To evaluate the quality of the results, a set of seven GCPs (Ground Control Points) measured by means of the NRTK (Network Real Time Kinematic) technique was used. The outcomes show a RMSE (Root Mean Square Error) of 0.0189 m for an ALLOY Base, 0.0194 m for an RS2 Base and 0.0511 m for RING Base, respectively, on the vertical value of DEMs (Digital Elevation Models) obtained by a photogrammetric process. This indicates that, when changing the Base for the PPK, the solutions are different, but they can still be considered adequate for precision positioning with UAVs, especially when GCPs could be used with some difficulty. Therefore, the integration of a RTK/PPK GNSS module on a UAV allows the reconstruction of a highly detailed and precise DEM without using GCPs and provides the possibility to carry out surveys in inaccessible areas.
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Barba, S., M. Barbarella, A. Di Benedetto, M. Fiani, and M. Limongiello. "QUALITY ASSESSMENT OF UAV PHOTOGRAMMETRIC ARCHAEOLOGICAL SURVEY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W9 (January 31, 2019): 93–100. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w9-93-2019.
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<p><strong>Abstract.</strong> The paper reports the results of a photogrammetric survey made using an Unmanned Aerial Vehicle (UAV) in the archaeological site of the Roman Amphitheatre in Avella (Avellino, Italy). The aim of the study is to verify which modality of image acquisition (if only nadiral images or nadiral plus Oblique images), together with the method of Global Positioning Satellite System (GNSS) survey of the Ground Control Points (GCP) is able to produce the better 3D model, in terms of accuracy, in order to extract traditional graphic drawings (plan, elevation and section), suited to the required representation scales (1<span class="thinspace"></span>:<span class="thinspace"></span>100 and 1<span class="thinspace"></span>:<span class="thinspace"></span>50). The accuracy in georeferencing was evaluated analysing the residues on the GCPs; subsequently, a more detailed analysis of the accuracy of the final 3D model was performed analysing the residuals on the image coordinates, also called re-projection error. The method developed is based on the statistical analysis of the different models, built changing the GCPs survey method and the photogrammetric shots acquired. The results of our analysis show that the photogrammetric survey is more ‘stable’ using only nadiral images and that the nRTK technique allows results comparable to those obtained with static measurements, both in precision and in reliability. Moreover, if the GCPs are measured in nRTK mode, taking into consideration the graphical error, the maximum representation scale is 1<span class="thinspace"></span>:<span class="thinspace"></span>100, whereas the use of static technique makes it possible to describe major details, at a scale of 1<span class="thinspace"></span>:<span class="thinspace"></span>50.</p>
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Amirrudin, Muhammad Afiq, Ami Hassan Md Din, Nur Adilla Zulkifli, Muhammad Asyran Che Amat, and Mohammad Hanif Hamden. "ASSESSMENT OF THE ACCURACY AND PRECISION OF MyRTKnet REAL-TIME SERVICES." Jurnal Teknologi 83, no. 1 (December 7, 2020): 93–103. http://dx.doi.org/10.11113/jurnalteknologi.v83.13892.
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From a network of ninety-six (96) Continuously Operating Reference Stations (CORS), the Department of Survey and Mapping Malaysia (DSMM) has developed a reliable real-time data streaming service known as the Malaysia Real-Time Kinematic GNSS Network (MyRTKnet). MyRTKnet is now operating on Leica SpiderNet system that is configured to provide coordinate to users in Geocentric Datum of Malaysia 2000 (GDM2000). As the name implied, GDM2000 is a geocentric datum for Malaysia, developed based upon the International Terrestrial Reference Frame (ITRF) 2000 or ITRF2000. One could argue that the quality of coordinates provided by MyRTKnet are less optimal as the latest realisation of ITRF at present is ITRF2014. This study aims to investigate the accuracy and precision of the resultant coordinates from MyRTKnet real-time services through a comparison with the control-quality coordinates from a network of post-processed data at some independent points for positioning purpose. Meanwhile for mapping purpose, the coordinates from Network Real-Time Kinematic (NRTK) at selected Cadastral Reference Marks (CRM) points were compared with their known values. The results show that the observed points in ITRF2000 move approximately 37 cm away from the points in ITRF2014 due to the constant movement of Sundaland Block. Meanwhile for the assessment of NRTK technique, there is no significant displacement for coordinates in ITRF2000 but ITRF2014 with the values of 4.4 and 39.8 cm at KDOJ point, respectively. The discrepancy in ITRF2014 could be due to the improper datum transformation procedure.
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Taddia, Yuri, Laura González-García, Elena Zambello, and Alberto Pellegrinelli. "Quality Assessment of Photogrammetric Models for Façade and Building Reconstruction Using DJI Phantom 4 RTK." Remote Sensing 12, no. 19 (September 24, 2020): 3144. http://dx.doi.org/10.3390/rs12193144.
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Aerial photogrammetry by Unmanned Aerial Vehicles (UAVs) is a widespread method to perform mapping tasks with high-resolution to reconstruct three-dimensional (3D) building and façade models. However, the survey of Ground Control Points (GCPs) represents a time-consuming task, while the use of Real-Time Kinematic (RTK) drones allows for one to collect camera locations with an accuracy of a few centimeters. DJI Phantom 4 RTK (DJI-P4RTK) combines this with the possibility to acquire oblique images in stationary conditions and it currently represents a versatile drone widely used from professional users together with commercial Structure-from-Motion software, such as Agisoft Metashape. In this work, we analyze the architectural application of this drone to the photogrammetric modeling of a building with particular regard to metric survey specifications for cultural heritage for 1:20, 1:50, 1:100, and 1:200 scales. In particular, we designed an accuracy assessment test signalizing 109 points, surveying them with total station and adjusting the measurements through a network approach in order to achieve millimeter-level accuracy. Image datasets with a designed Ground Sample Distance (GSD) of 2 mm were acquired in Network RTK (NRTK) and RTK modes in manual piloting and processed both as single façades (S–F) and as an overall block (4–F). Subsequently, we compared the results of photogrammetric models generated in Agisoft Metashape to the Signalized Point (SP) coordinates. The results highlight the importance of processing an overall photogrammetric block, especially whenever part of camera locations exhibited a poorer accuracy due to multipath effects. No significant differences were found between the results of network real-time kinematic (NRTK) and real-time kinematic (RTK) datasets. Horizontal residuals were generally comparable to GNSS accuracy in NRTK/RTK mode, while vertical residuals were found to be affected by an offset of about 5 cm. We introduced an external GCP or used one SP per façade as GCP, assuming a poorer camera location accuracy at the same time, in order to fix this issue and comply with metric survey specifications for the widest architectural scale range. Finally, both S–F and 4–F projects satisfied the metric survey requirements of a scale of 1:50 in at least one of the approaches tested.
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Tufarolo, E., C. Vanneschi, M. Casella, and R. Salvini. "EVALUATION OF CAMERA POSITIONS AND GROUND POINTS QUALITY IN A GNSS-NRTK BASED UAV SURVEY: PRELIMINARY RESULTS FROM A PRACTICAL TEST IN MORPHOLOGICAL VERY COMPLEX AREAS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W13 (June 4, 2019): 637–41. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w13-637-2019.
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<p><strong>Abstract.</strong> Open pit mines localized in high mountains are probably one of the most complex environments for Structure-From-Motion (SfM) based photogrammetry. The case study presented in this paper refers to the realization of a detailed topographic mapping in the Torano marble basin (Apuan Alps, Italy) which needed, after decades of excavation activity, a new topographic survey.</p><p>Given the requested very high resolution, the time constraints and safety-related problems, a photogrammetric approach by a fixedwing Unmanned Aerial Vehicle (UAV) was chosen to carry out thesurvey of the basin. In addition, given the morphological complexity of the area, characterized by extreme steep slopes more than hundreds of meters high, and the necessity to minimize the fieldwork without sacrificing the work quality, an UAV equipped with a L1/L2 Network Real Time Kinematic (NRTK) Global Navigation Satellite System (GNSS) was used.</p><p>The scope of this work is to compare the accuracy of UAV derived 3D photogrammetric models realized with different approaches: by using traditional Ground Control Points (GCPs), by using the on-board Network Real Time Kinematic system for camera position detection, and a mix of both. At the end, we tested the quality of the models to verify the reachable levels of accuracy.</p>
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Bae, Tae-Suk, and Minho Kim. "Performance Analysis of Network-RTK Techniques for Drone Navigation considering Ionospheric Conditions." Journal of Sensors 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/5154697.
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Recently, an accurate positioning has become the kernel of autonomous navigation with the rapid growth of drones including mapping purpose. The Network-based Real-time Kinematic (NRTK) system was predominantly used for precision positioning in many fields such as surveying and agriculture, mostly in static mode or low-speed operation. The NRTK positioning, in general, shows much better performance with the fixed integer ambiguities. However, the success rate of the ambiguity resolution is highly dependent on the ionospheric condition and the surrounding environment of Global Navigation Satellite System (GNSS) positioning, which particularly corresponds to the low-cost GNSS receivers. We analyzed the effects of the ionospheric conditions on the GNSS NRTK, as well as the possibility of applying the mobile NRTK to drone navigation for mapping. Two NRTK systems in operation were analyzed during a period of high ionospheric conditions, and the accuracy and the performance were compared for several operational cases. The test results show that a submeter accuracy is available even with float ambiguity under a favorable condition (i.e., visibility of the satellites as well as stable ionosphere). We still need to consider how to deal with ionospheric disturbances which may prevent NRTK positioning.
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Koivula, Hannu, Jaakko Kuokkanen, Simo Marila, Sonja Lahtinen, and Tuukka Mattila. "Assessment of sparse GNSS network for network RTK." Journal of Geodetic Science 8, no. 1 (December 1, 2018): 136–44. http://dx.doi.org/10.1515/jogs-2018-0014.
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Abstract We tested the accuracy and usability of a sparse GNSS reference station network for network RTK (NRTK) using the Finnish permanent GNSS network FinnRef. We modified the configuration of the FinnRef network stations used in NRTK computation. This allowed us to perform the test both inside and outside of the network area using different NRTK methods and two different RTK receivers. In the test area the average distance between the FinnRef stationswas 160 km. As a comparison,we tested also with the commercial Trimnet and HxGN SmartNet positioning services operated by Geotrim Oy and Leica Geosystems Finland, respectively. Tests showed that the horizontal and vertical rms of Trimnet servicewas 16mmand 40 mm, and of HxGN SmartNet service 23mmand 48 mm. The best rms for the sparse NLS (National Land Survey of Finland) Service was 22 mm and 56 mm. These results indicate that a good NRTK solution can be achieved with a sparser network than typically used. This study also indicates, that the methods for NRTK processing can also affect the quality of the solution.
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Xu, Ying, and Wu Chen. "Performance Analysis of GPS/BDS Dual/Triple-Frequency Network RTK in Urban Areas: A Case Study in Hong Kong." Sensors 18, no. 8 (July 26, 2018): 2437. http://dx.doi.org/10.3390/s18082437.
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Network Real Time Kinematic (NRTK) positioning with instantaneous ambiguity resolution (AR) is currently one of the most popular techniques for real-time precise positioning using Global Navigation Satellite Systems (GNSS) carrier phase observations. Although NRTK has been successfully applied in many fields in surveying and navigation, the initialization speed, accuracy, and ambiguity successfully fixed rate of NRTK in urban areas (Hong Kong, for instance) would be significantly affected by blocked satellite signals. To address these problems and analyze the performance of GPS/BDS dual/triple-frequency NRTK in urban areas, we developed a new Hong Kong GNSS Network RTK Service Platform. Based on this platform, the performance of NRTK in urban areas was examined through a series of experiments. The results showed that: (1) The initialization time of the NRTK varied with the number of the visible satellite and the quality of the observation. (2) Centimeter-level NRTK service could be provided for users over Hong Kong using the Hong Kong GNSS Network RTK Service Platform. (3) In urban areas, GPS/BDS NRTK services for static, walking, and driving users significantly improved the ambiguity successfully fixed rate of the NRTK service when compared with that using the GPS signal alone. The NRTK ambiguity successfully fixed rate in Hong Kong was better than 99% in good environment. In typical urban environment, the RTK ambiguity successfully fixed rate with GPS/BDS was 33.4–72.4%, which was about 12.7–32.4% with GPS only. (4) BDS triple-frequency observation improved the initialization speed and positioning accuracy of RTK in Hong Kong.
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Pepe, Massimiliano. "CORS ARCHITECTURE AND EVALUATION OF POSITIONING BY LOW-COST GNSS RECEIVER." Geodesy and cartography 44, no. 2 (August 8, 2018): 36–44. http://dx.doi.org/10.3846/gac.2018.1255.
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In recent years, the use of low cost GNSS receivers is becoming widespread due to their increasing performance in the spatial positioning, flexibility, ease of use and really interesting price. In addition, a recent technique of Global Navigation Satellite System (GNSS) survey, called Network Real Time Kinematic (NRTK), allows to obtain to rapid and accurate positioning measurements. The main feature of this approach is to use the raw measurements obtained and stored from a network of Continuously Operating Reference Stations (CORS) in order to generate more reliable error models that can mitigate the distance-dependent errors within the area covered by the CORS. Also, considering the huge potential of this GNSS positioning system, the purpose of this paper is to analyze and investigate the performance of the NTRK approach using a low cost GNSS receiver, in stop-and-go kinematic technique. By several case studies it was shown that, using a low cost RTK board for Arduino environment, a smartphone with open source application for Android and the availability of data correction from CORS service, a quick and accurate positioning can be obtained. Because the measures obtained in this way are quite noisy and, more in general, increasing with the baseline, by a simple and suitable statistic treatment, it was possible to increase the quality of the measure. In this way, this low cost architecture could be applied in many geomatics fields. In addition to presenting the main aspects of the NTRK infrastructure and a review of several types of correction, a general workflow in order to obtain quality data in NRTK mode, regardless of the type of GNSS receiver (multi constellations, single or many frequencies, etc.) is discussed.
Dissertations / Theses on the topic "GNSS NRTK Quality control"
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DABOVE, PAOLO. "Quality control of the kinematic positioning into GNSS networks." Doctoral thesis, Politecnico di Torino, 2013. http://hdl.handle.net/11583/2507275.
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GNSS (Global Navigation Satellite System) positioning is nowadays a common practice, not only in academia but also in the professional world, thanks to the development of several types of instruments and the decreasing costs of the receivers and antennae.
Today, considering also the new constellations that are emerging, it is possible to affirm that GNSS positioning can be assessed almost everywhere: therefore, it is no longer necessary to ask whether satellite positioning is possible but rather how precise it can be.
The main focus and goal of this thesis is to suggest new and innovative methodologies to control the quality of the positioning, focusing attention on the network positioning both in real time and post processing. Different types of instruments will be considered, in terms of both cost and performance: in fact, geodetic, GIS and mass-market receivers will be considered when used for Network Real-Time Kinematic (NRTK) or differential positioning.
This thesis consists of five enlightening chapters.
Chapter 1 includes a brief introduction to the subject as well as encompassing the research objectives and this outline.
Chapter 2 outlines the quality control of geodetic and GIS receivers in a network of permanent stations, considering different types of networks, as a function of inter-station distances.
Chapter 3 focuses attention on the quality of ambiguity fixing, considering an innovative method based on the creation of a tool that is able to predict a wrong geodetic receiver fix when it is used in a CORSs (Continuously Operating Reference Stations) network.
Chapter 4 describes the quality control of the positioning when mass-market instruments (receivers and antennae) were used both in a network of permanent stations and as a network itself.
Chapter 5 gives the conclusions and recommendations for further work.
Two appendices conclude this work: the first concerns the Kalman filter in geodesy and its importance for real-time positioning, considering both the classical configuration and other versions (e.g. the extended Kalman filter and unscented Kalman filter); the second analyses more deeply the neural network concepts that are mentioned briefly in Chapter 3.
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Hewitson, Steve Surveying & Spatial Information Systems Faculty of Engineering UNSW. "Quality control for integrated GNSS and inertial navigation systems." Awarded by:University of New South Wales. Surveying and Spatial Information Systems, 2006. http://handle.unsw.edu.au/1959.4/25534.
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The availability of GPS signals is a major limitation for many existing and potential applications. Fortunately, with the development of Galileo by the European Commission (EC) and European Space Agency (ESA) and new funding for the restoration of the Russian GLONASS announced by the Russian Federation the future for satellite based positioning and navigation applications is extremely promising. This research primarily investigates the benefits of GNSS interoperability and GNSS/INS integration to Receiver Autonomous Integrity Monitoring (RAIM) from a geometrical perspective. In addition to these investigations, issues regarding multiple outlier detection and identification are examined and integrity procedures addressing these issues are proposed. Moreover, it has been shown how the same RAIM algorithms can be effectively applied to the various static and kinematic navigation architectures used in this research.
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Wang, Lei. "Reliability control of GNSS carrier-phase integer ambiguity resolution." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/86976/1/Lei_Wang_Thesis.pdf.
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This research investigates how to obtain accurate and reliable positioning results with global navigation satellite systems (GNSS). The work provides a theoretical framework for reliability control in GNSS carrier phase ambiguity resolution, which is the key technique for precise GNSS positioning in centimetre levels. The proposed approach includes identification and exclusion procedures of unreliable solutions and hypothesis tests, allowing the reliability of solutions to be controlled in the aspects of mathematical models, integer estimation and ambiguity acceptance tests. Extensive experimental results with both simulation and observed data sets effectively demonstrate the reliability performance characteristics based on the proposed theoretical framework and procedures.
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Goode, Matthew Emyr David. "Quality control procedures for GNSS precise point positioning in the presence of time correlated residuals." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2533.
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Precise point positioning (PPP) is a technique for processing Global Navi- gation Satellite Systems (GNSS) data, often using recursive estimation methods e.g. a Kalman Filter, that can achieve centimetric accuracies using a single receiver. PPP is now the dominant real-time application in o shore marine positioning industry. For high precision real-time applications it is necessary to use high rate orbit and clock corrections in addition to high rate observations. As Kalman filters require input of process and measurement noise statistics, not precisely known in practice, the filter is non-optimal. Geodetic quality control procedures as developed by Baarda in the 1960s are well established and their extension to GNSS is mature. This methodology, largely unchanged since the 1990s, is now being applied to processing techniques that estimate more parameters and utilise many more observations at higher rates. \Detection, Identification and Adaption" (DIA), developed from an optimal filter perspective and utilising Baarda's methodology, is a widely adopted GNSS quality control procedure. DIA utilises various test statistics, which require observation residuals and their variances. Correct derivation of the local test statistic requires residuals at a given epoch to be uncorrelated with those from previous epochs. It is shown that for a non-optimal filter the autocorrelations between observations at successive epochs are non-zero which has implications for proper application of DIA. Whilst less problematic for longer data sampling periods, high rate data using real-time PPP results in significant time correlations between residuals over short periods. It is possible to model time correlations in the residuals as an autoregressive process. Using the autoregressive parameters, the effect of time correlation in the residuals can be removed, creating so-called whitened residuals and their variances. Thus a whitened test statistic can be formed, that satisfies the preferred assumption of uncorrelated residuals over time. The effectiveness of this whitened test statistic and its impact on quality control is evaluated.
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Nicolau, Francisca Edcarla de Araujo. "Raios de curvatura, larguras de bitola e comprimentos do cabeçalho influenciam na qualidade do paralelismo? /." Jaboticabal, 2020. http://hdl.handle.net/11449/192275.
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Orientador: Carlos Eduardo Angeli FurlaniResumo: As propriedades que atuam no deslizamento lateral de um equipamento de arrasto em áreas agrícolas, variam amplamente, indo desde as relacionadas ao solo até aos parâmetros envolvidos no sistema trator-equipamento que podem afetar o deslocamento lateral. O objetivo com o estudo foi mensurar o erro de paralelismo do conjunto trator-protótipo em função de diferentes raios de curvatura, larguras de bitola e comprimentos do cabeçalho de um protótipo de arrasto, além de avaliar a variabilidade do processo por meio do Controle Estatístico do Processo. Os testes foram realizados em área experimental da Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Câmpus de Jaboticabal. Foi adaptado o chassi de uma semeadora-adubadora, que possibilitasse mudança no comprimento do cabeçalho e variação na largura da bitola do equipamento, o qual denominamos protótipo de arrasto. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 5x4x15, com cinco comprimentos do cabeçalho e quatro larguras de bitola do protótipo em quinze raios de curvatura médio. A medição do paralelismo entre as passadas do conjunto trator-protótipo foi obtida por meio de um instrumento desenvolvido que denominamos “pirulito” e com o auxílio de uma trena. Nos raios de 16,4 m e de 20 m os erros de paralelismo são maiores, em todas as bitolas e vão diminuindo à medida que se aumenta a circunferência do raio. O comprimento do cabeçalho de 2,40 m, quando comparado com ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The properties that act on the lateral sliding of a trailed equipment in agricultural areas, change widely, ranging from those related to the soil to the parameters involved in the tractor-equipment system that can affect lateral displacement. The objective of the study was to measure the parallelism error of the tractor-prototype set as a function of different curvature radius, the widths of the gauge and the lengths of the header of a drag prototype, in addition, the evaluating process of the variability through the Statistical Process Control. The tests were carried out in an experimental area at the São Paulo State University (Unesp), School of Agricultural and Veterinary Sciences, Campus of Jaboticabal. The chassis of a seeder-fertilizer was adopted, so that it would allow a change in the length of the header and a variation in the width of the gauge of the equipment, which we call the trailed prototype. The experimental design was entirely randomized, in a 5x4x15 factorial scheme, with five header lengths and four widths of gauge of the prototype in fifteen average curvature radius. The measurement of the parallelism between the steps of the tractor-prototype set was obtained by using an instrument that we call “lollipop” and with the help of a measuring tape. In the 16.4 m and 20 m radius the parallelism errors were greater than the other gauges, and it decreased as the radius circumference increased. The header length of 2.40 m, when compared to the others, obtained t... (Complete abstract click electronic access below)
Doutor
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(6843914), Radhika Ravi. "Interactive Environment For The Calibration And Visualization Of Multi-sensor Mobile Mapping Systems." Thesis, 2019.
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LiDAR units onboard airborne and terrestrial platforms have been established as a proven technology for the acquisition of dense point clouds for a wide range of applications, such as digital building model generation, transportation corridor monitoring, precision agriculture, and infrastructure monitoring. Furthermore, integrating such systems with one or more cameras would allow forward and backward projection between imagery and LiDAR data, thus facilitating several high-level data processing activities such as reliable feature extraction and colorization of point clouds. However, the attainment of the full 3D point positioning potential of such systems is contingent on an accurate calibration of the mobile mapping unit as a whole.
This research aims at proposing a calibration procedure for terrestrial multi-unit LiDAR systems to directly estimate the mounting parameters relating several spinning multi-beam laser scanners to the onboard GNSS/INS unit in order to derive point clouds with high positional accuracy. To ensure the accuracy of the estimated mounting parameters, an optimal configuration of target primitives and drive-runs is determined by analyzing the potential impact of bias in mounting parameters of a LiDAR unit on the resultant point cloud for different orientations of target primitives and different drive-run scenarios. This impact is also verified experimentally by simulating a bias in each mounting parameter separately. Next, the optimal configuration is used within an experimental setup to evaluate the performance of the proposed calibration procedure. Then, this proposed multi-unit LiDAR system calibration strategy is extended for multi-LiDAR multi-camera systems in order to allow a simultaneous estimation of the mounting parameters relating the different laser scanners as well as cameras to the onboard GNSS/INS unit. Such a calibration improves the registration accuracy of point clouds derived from LiDAR data and imagery, along with their accuracy with respect to the ground truth. Finally, in order to qualitatively evaluate the calibration results for a generic mobile mapping system and allow the visualization of point clouds, imagery data, and their registration quality, an interface denoted as Image-LiDAR Interactive Visualization Environment (I-LIVE) is developed. Apart from its visualization functions (such as 3D point cloud manipulation and image display/navigation), I-LIVE mainly serves as a tool for the quality control of GNSS/INS-derived trajectory and LiDAR-camera system calibration.
The proposed multi-sensor system calibration procedures are experimentally evaluated by calibrating several mobile mapping platforms with varying number of LiDAR units and cameras. For all cases, the system calibration is seen to attain accuracies better than the ones expected based on the specifications of the involved hardware components, i.e., the LiDAR units, cameras, and GNSS/INS units.
Book chapters on the topic "GNSS NRTK Quality control"
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Chen, Hanzhi, and Rui Sun. "A GNSS Quality Control Based GNSS/IMU Integrated Navigation Algorithm in Urban Environments." In Lecture Notes in Electrical Engineering, 426–36. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2588-7_40.
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Yang, Ling, Yong Li, and Youlong Wu. "Efficient Quality Control Procedure for GNSS/INS Integrated Navigation System." In Lecture Notes in Electrical Engineering, 673–84. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-37407-4_62.
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Qiu, Ming, and Rui Sun. "W-Test Aided Quality Control Algorithm for GNSS/IMU Integrated Navigation in Urban Environments." In Lecture Notes in Electrical Engineering, 540–48. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-3146-7_50.
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Lutz, Alexander, and Axel Lachmeyer. "SciPPPer: Automatic Lock-Passage for Inland Vessels – Practical Results Focusing on Control Performance." In Lecture Notes in Civil Engineering, 959–68. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-6138-0_85.
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AbstractNavigating through locks is one of the most challenging tasks that skippers have to perform in inland navigation. Typical dimensions of a ship (width = 11.45 m) and a lock (width = 12 m) result in an error margin of less than 30 cm to the left and to the right of the ship when navigating within a lock chamber. Typical inland vessels on European waters have a length of 82 to 186 m. The wheel house on cargo vessels is located close to the stern of the vessel. This leads to low visibility of the bow in the lock chamber. In order to cope with this issue, a deck hand monitors the bow and announces distances to the skipper via radio. The quality of this information depends on the deck hand’s ability to judge distances correctly and is prone to error. This highly demanding maneuver needs to be performed up to 15 times per day. Each lock passage can take up to 30 minutes. The research project SciPPPer aims at automating this complex navigational task.The German acronym SciPPPer stands for Schleusenassistenzsystem basierend auf PPP und VDES für die Binnenschifffahrt – lock assistant system based on PPP and VDES for inland navigation. The idea is to fully automate the navigation into and out of a lock using high-precision GNSS (Global Navigation Satellite System) with PPP (precise point positioning) correction data which is transmitted from shore to ship using VDES (VHF Data Exchange System), an extension to AIS (Automatic Identification System). This absolute measurement data is complemented by relative measurement data using LiDAR and automotive RADAR and fused with inertial measurement data delivered by a mechanical gyro system. Apart from the challenge of precisely measuring the position and orientation of the vessel within the lock chamber, the control task poses an interesting problem as well. This contribution introduces both, the measuring and the control problem. However, the focus lies on the results of the control performance that was achieved on a full-bridge simulator as well as during real-world trials. A full-bridge simulator was used in order to test the control strategy and its algorithms safely. A number of different actuator configurations were investigated. Typical inland cargo vessels use one or two propellers with Kort nozzle and a twin rudder behind each propeller and a 360° turnable bow thruster. Typical inland passenger vessels use several (2–4) 360° turnable rudder propellers as main propulsion as well as a 360° turnable bow thruster or a classical tunnel thruster which can only apply forces to starboard or portside. These typical configurations were examined by simulation. The real-world trials were performed on a passenger vessel with three rudder propellers as main propulsion as well as a classical tunnel bow thruster acting left and right.This contribution presents the results of the simulator study as well as the real-world trials in terms of control performance. It explains specific challenges due to the navigation within an extremely confined space. The contribution concludes with lessons learned as well as an outlook focusing on the potential of the introduction of such a system to the inland navigation market.
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Estanqueiro, Rossana, José António Tenedório, Carla Rebelo, and Joao Pedro Marques. "Future 3D Urbanism." In Methods and Applications of Geospatial Technology in Sustainable Urbanism, 552–85. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-2249-3.ch018.
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Urbanism has mainly used 2D data for both the urban analysis and diagnosis and the presentation of proposals for changes in the whole city or parts of the city. Even regarding the production of urban indicators, using, for example, the quantification of the existing green area in relation to the resident population, this practice is regularly based on the area and rarely on volume. This situation is mainly justified by the sluggishness and costs associated with obtaining 3D data. The recent development of data collection technology by unmanned aerial vehicles has triggered a change in this scenario. This chapter presents the UAV data acquisition and processing chain, analyses the positional accuracy of UAV data processing performed with GCP measurements obtained from GNSS, demonstrates how positional accuracy assessment and UAV workflow's quality control are relevant for ensuring the accuracy of derived UAV geospatial products, and demonstrates the usability of 3D models in a theoretical 3D urbanism context.
Conference papers on the topic "GNSS NRTK Quality control"
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Huang, Wenjie, and Lei Wang. "Adaptive tracking channel control for GNSS receivers under renewable energy." In 2015 16th International Symposium on Quality Electronic Design (ISQED). IEEE, 2015. http://dx.doi.org/10.1109/isqed.2015.7085427.
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Arai, Hironori, Mehrez Zribi, Kei Oyoshi, Karin Dassas, Mireille Huc, Shinichi Sobue, and Thuy Le Toan. "Quality Control of Cygnss GNSS-Reflectivity for Robust Spatio-Temporal Detection of Tropical Wetlands." In IGARSS 2022 - 2022 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2022. http://dx.doi.org/10.1109/igarss46834.2022.9883228.
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Lu, Debiao, Baigen Cai, Jian Wang, Jiang Liu, and Federico Grasso Toro. "Safety Margin Estimation Using Risk Assessment Method for Satellite-Based Train Localization Unit." In 2016 Joint Rail Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/jrc2016-5803.
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Safety as the key quality property among RAMS (reliability, availability, maintainability, and safety) demonstrates the most stringent performance in correspondence with the safety requirements and performance standards like EN 50126. Meanwhile, GNSS (Global Navigation Satellite Systems) are penetrating the railway now widely in non-safety related applications as passenger information, fleet management, etc. GNSS also have great potential for safety-related applications in railway such as the train location determination function, which the safety performance needs to be assured through hazard analysis and risk assessment process. The train location determination by satellite-based localization system is elevating the train control to the next level. The European Train Control System (ETCS) has being trying to implementing Level 3, the Chinese Train Control System (CTCS) has been implementing CTCS Level 3 low cost especially for secondary lines, and the U.S. is implementing train control systems under Positive Train Control (PTC) requirements. The train control system needs GNSS to provide more accurate location information of trains, more flexible and condensed trains on tracks with the consistency of still keeping the current safety level or even improve safety. Some researchers are trying to understand the performance of GNSS (GPS / EGNOS / Beidou) for railway applications from the fundamental accuracy level. A satellite-based train localization unit (SaLuT) as the entity to perform the train location determination function is to bring the GNSS accuracy evaluation up to safety integrity according to the safety requirements and standards for risk assessment. One of the key consequential result derived from the train location is the adequate safety margin. The safety margin, which can also be called as “safe braking distance”, is a margin indicated to rail traffic that would allow the train to stop with the application of normal service braking. The safety margin estimation quality and the risk of the safety margin shows the hazard rate for the safety margin estimation function performed by the designed localization unit SaLuT. This paper discusses the safety margin estimation method considering both GNSS accuracy and integrity assessment aspects of SaLuT, in accordance of the settled safety requirements of location determination function. To analyze the hazard of the safety margin estimation, a formal method is applied to model the SaLuT behavior and functions. The formal method based on stochastic Petri net enables the modeling process to include the GNSS receiver collected real data on the test track into it. The safety margin estimation method together with the risk assessment method using the real data can generate quantitative indicators to represent the localization function and safety margin estimation quality. The data used for the analysis is collected in the Qinghai-Tibet railway line from Golmud station to Ganlong station by SaLuT installed on a locomotive along the track. With the stochastic Petri net model and the systematic equation using the real collected data to estimate the safety margin based on the GNSS technologies, the SaLuT can be validated and verified for its hazard rates, which provides information for the safety cases in order to meet the industrial normative requirements.
Reports on the topic "GNSS NRTK Quality control"
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Bhatt, Parth, Curtis Edson, and Ann MacLean. Image Processing in Dense Forest Areas using Unmanned Aerial System (UAS). Michigan Technological University, September 2022. http://dx.doi.org/10.37099/mtu.dc.michigantech-p/16366.
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Imagery collected via Unmanned Aerial System (UAS) platforms has become popular in recent years due to improvements in a Digital Single-Lens Reflex (DSLR) camera (centimeter and sub-centimeter), lower operation costs as compared to human piloted aircraft, and the ability to collect data over areas with limited ground access. Many different application (e.g., forestry, agriculture, geology, archaeology) are already using and utilizing the advantages of UAS data. Although, there are numerous UAS image processing workflows, for each application the approach can be different. In this study, we developed a processing workflow of UAS imagery collected in a dense forest (e.g., coniferous/deciduous forest and contiguous wetlands) area allowing users to process large datasets with acceptable mosaicking and georeferencing errors. Imagery was acquired with near-infrared (NIR) and red, green, blue (RGB) cameras with no ground control points. Image quality of two different UAS collection platforms were observed. Agisoft Metashape, a photogrammetric suite, which uses SfM (Structure from Motion) techniques, was used to process the imagery. The results showed that an UAS having a consumer grade Global Navigation Satellite System (GNSS) onboard had better image alignment than an UAS with lower quality GNSS.
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Pstuty, Norbert, Mark Duffy, Dennis Skidds, Tanya Silveira, Andrea Habeck, Katherine Ames, and Glenn Liu. Northeast Coastal and Barrier Network Geomorphological Monitoring Protocol: Part I—Ocean Shoreline Position, Version 2. National Park Service, June 2022. http://dx.doi.org/10.36967/2293713.
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Following a review of Vital Signs – indicators of ecosystem health – in the coastal parks of the Northeast Coastal and Barrier Network (NCBN), knowledge of shoreline change was ranked as the top variable for monitoring. Shoreline change is a basic element in the management of any coastal system because it contributes to the understanding of the functioning of the natural resources and to the administration of the cultural resources within the parks. Collection of information on the vectors of change relies on the establishment of a rigorous system of protocols to monitor elements of the coastal geomorphology that are guided by three basic principles: 1) all of the elements in the protocols are to be based on scientific principles; 2) the products of the monitoring must relate to issues of importance to park management; and 3) the application of the protocols must be capable of implementation at the local level within the NCBN. Changes in ocean shoreline position are recognized as interacting with many other elements of the Ocean Beach-Dune Ecosystem and are thus both driving and responding to the variety of natural and cultural factors active at the coast at a variety of temporal and spatial scales. The direction and magnitude of shoreline change can be monitored through the application of a protocol that tracks the spatial position of the neap-tide, high tide swash line under well-defined conditions of temporal sampling. Spring and fall surveys conducted in accordance with standard operating procedures will generate consistent and comparable shoreline position data sets that can be incorporated within a data matrix and subsequently analyzed for temporal and spatial variations. The Ocean Shoreline Position Monitoring Protocol will be applied to six parks in the NCBN: Assateague Island National Seashore, Cape Cod National Seashore, Fire Island National Seashore, Gateway National Recreation Area, George Washington Birthplace National Monument, and Sagamore Hill National Historic Site. Monitoring will be accomplished with a Global Positioning System (GPS )/ Global Navigation Satellite System (GNSS) unit capable of sub-meter horizontal accuracy that is usually mounted on an off-road vehicle and driven along the swash line. Under the guidance of a set of Standard Operating Procedures (SOPs) (Psuty et al., 2022), the monitoring will generate comparable data sets. The protocol will produce shoreline change metrics following the methodology of the Digital Shoreline Analysis System developed by the United States Geological Survey. Annual Data Summaries and Trend Reports will present and analyze the collected data sets. All collected data will undergo rigorous quality-assurance and quality-control procedures and will be archived at the offices of the NCBN. All monitoring products will be made available via the National Park Service’s Integrated Resource Management Applications Portal.