Showing papers in "Journal of Surveying Engineering-asce in 2013"
TL;DR: In this paper, a point-based voxelization method was proposed to automatically transform point cloud data into solid models for computational modeling for both aerial and terrestrial data, which was achieved in less than 30 s for data sets up to 650,000 points.
Abstract: Automated conversion of point cloud data from laser scanning into formats appropriate for structural engineering holds great promise for exploiting increasingly available aerially and terrestrially based pixelized data for a wide range of surveying-related applications from environmental modeling to disaster management. This paper introduces a point-based voxelization method to automatically transform point cloud data into solid models for computational modeling. The fundamental viability of the technique is visually demonstrated for both aerial and terrestrial data. For aerial and terrestrial data, this was achieved in less than 30 s for data sets up to 650,000 points. In all cases, the solid models converged without any user intervention when processed in a commercial finite-element method program.
73 citations
TL;DR: The 3σ-rule is a simple and widely used heuristic for outlier detection as mentioned in this paper, which is a generic term of some statistical hypothesis tests whose test statistics are known as normalized or studentized residuals.
Abstract: The so-called 3σ-rule is a simple and widely used heuristic for outlier detection. This term is a generic term of some statistical hypothesis tests whose test statistics are known as normalized or studentized residuals. The conditions, under which this rule is statistically substantiated, were analyzed, and the extent it applies to geodetic least-squares adjustment was investigated. Then, the efficiency or nonefficiency of this method was analyzed and demonstrated on the example of repeated observations.
70 citations
TL;DR: In this article, the authors combine image-matching-based reconstruction and model-based image fitting to achieve sub-millimeter precision for the estimation of both vertical deflections and horizontal displacements.
Abstract: Periodic structural health monitoring of infrastructure systems is important to avoid economic losses and human casualties. Traditionally, deformation monitoring has been done through surveying techniques. Recently, with the increased availability of inexpensive off-the-shelf cameras, photogrammetry has become a viable noncontact alternative for complete three-dimensional reconstruction of the object or surface of interest. This paper aims at combining two methodologies of photogrammetric reconstruction—image-matching-based reconstruction and model-based image fitting—to achieve submillimeter precision for the estimation of both vertical deflections and horizontal displacements. The proposed methodology was tested with data collected using a photogrammetric system at a structures laboratory where a concrete beam was subjected to different loading conditions by a hydraulic actuator. The experimental results showed that the photogrammetric system was capable of monitoring both static and dynamic deformations. The methodology used exhibited a high level of automation and the final results yielded a root-mean-square error (RMSE) of half a millimeter.
41 citations
TL;DR: In this article, a method for the surveying and reliable processing of Global Navigation Satellite System (GNSS) observations in rapid and ultrarapid static surveying for determination of control-point coordinates is presented.
Abstract: This paper presents a method for the surveying and reliable processing of Global Navigation Satellite System (GNSS) observations in rapid and ultrarapid static surveying for determination of control-point coordinates. The presented technique allows for reliable determination of coordinates, even in the case of highly difficult observation conditions (e.g., for control points situated along forest edges or entirely in the forest, near buildings, or in the vicinity of power-transmission lines). The paper also analyzes different projects of the global positioning system (GPS/GLONASS) networks from the perspective of their credibility and reliability. The control-point coordinates are determined by three GNSS receivers positioned in line on a special base, providing a credible control of GNSS baselines during rapid and ultrarapid static surveys. The GNSS receivers are separated by the distance of 0.5 m. Given the gross errors in baseline coordinates determined that happen in practice, simultaneous use of three receivers for position determination of a control point allows reliable determination of the coordinates even under significantly obstructed access to satellites. The practical surveys were conducted using Topcon and Trimble receivers using real and virtual reference stations. The presented survey and GNSS data-processing methodology allow obtaining centimeter-level accuracy in a few minutes of GPS/GLONASS observations for control points located in obstructed conditions.
36 citations
TL;DR: In this article, the authors proposed a method for increasing satellite signal availability and positio-... for static and kinematic PPP based on the processing of global positioning system (GPS) observations, which is often insufficient for urban or mountain applications.
Abstract: Precise point positioning (PPP) involves observations from a single global navigation satellite system (GNSS) receiver and benefits of satellite orbit and clock products obtained from the global infrastructure of permanent stations. PPP avoids the expense and logistic difficulties of deploying a network of GNSS receivers around survey areas in isolated places, such as the arctic or less populated areas. Potential accuracies are at the centimeter level for static applications and at the subdecimeter level for kinematic applications. Static and kinematic PPP based on the processing of global positioning system (GPS) observations is limited by the number of visible satellites, which is often insufficient for urban or mountain applications, or it can be partially obstructed or present multipath effects. Even if a number of GPS satellites are available, the accuracy and reliability can still be affected by poor satellite geometry. One possible way of increasing satellite signal availability and positio...
36 citations
TL;DR: In this article, the authors investigated the effect of the subsidence experienced by continuously operating reference stations (CORS) around Houston on the accuracy of online positioning user service (OPUS) vertical results.
Abstract: The Houston area has been suffering from subsidence for several decades. Therefore, continuously operating reference stations (CORS) in this area may have experienced considerable vertical displacements. The Online Positioning User Service (OPUS), provided by the National Geodetic Survey (NGS), uses CORS as references in its data processing. This study investigated what effects, if any, the subsidence experienced by these CORS around Houston contributes to the accuracy of OPUS vertical results. Our OPUS results were determined from three long-term (over 10-year) blocks of continuous data using Global Positioning System (GPS) stations located in different parts of the Houston area. The OPUS results were compared with the vertical measurements from the precise point positioning with single receiver phase ambiguity (PPP-SRPA) solution implicit in the GIPSY/OASIS 6.1.2 software. This particular study indicates that OPUS achieves 1.0-cm vertical accuracy for daily sessions (24 h) in the region around H...
28 citations
TL;DR: In this paper, the least square variance component estimation is applied to global positioning system (GPS) observables using the geometry-based observation model (GBOM) rather than GFOM.
Abstract: To achieve the best linear unbiased estimation of unknown parameters in geodetic data processing a realistic stochastic model for observables is required. This work is a follow-up to work carried out recently in which the geometry-free observation model (GFOM) was used. Here, least-squares variance component estimation is applied to global positioning system (GPS) observables using the geometry-based observation model (GBOM). The benefit of using GBOM, rather than GFOM, is highlighted in the present contribution. An appropriate stochastic model for GPS observables should include different variances for each observation type, the correlation between different observables, the satellite elevation dependence of the observables’ precision, and the temporal correlation of the GPS observables. Unlike the GFOM, in the GBOM two separate variances along with their corresponding covariances are simultaneously estimated for the phase observations of the L1 and L2 frequencies. The numerical results for two re...
25 citations
TL;DR: In this paper, a sign-constrained robust least-squares (SRLS) method was proposed for surveying networks utilizing the shuffled frog-leaping algorithm (SFLA).
Abstract: The least-squares (LS) method is highly susceptible to outlying observations. For this reason, various types of robust estimators have been developed; for example, M estimators. In this paper, it is proposed to use the sign-constrained robust LS (SRLS) method in surveying networks utilizing the shuffled frog-leaping algorithm (SFLA). The robustness of SRLS is directly implemented as constraints. Therefore, a penalty function approach is used to deal with the constraints. In addition, the performance of any stochastic optimization approach such as SFLA strongly depends on the search domain. Hence, a strategy to define the boundaries of the search domain has been developed for use in surveying networks. The results indicate that SRLS yields better results than the LS method even if there are more outliers among the observations.
12 citations
TL;DR: In this article, the authors study the non-iterative method in terms of the multivariate least-squares theory with two-dimensional empirical affine transformation as a case study.
Abstract: In geospatial applications, the datum transformation has been necessarily employed to transform the geospatial outcomes from the data-collection system to the user-interested system. Its key is to compute the transformation parameters that describe the geometric relation between two datum systems. The ordinary least-squares based transformation parameter estimation needs the iterative computations unless the initial values of parameters are approximate enough, which is usually time-consuming. Particularly with the development of (near) real-time data collection techniques, such iterative datum transformation method cannot meet the real-time applications. In this paper, we study the noniterative method in terms of the multivariate least-squares theory with two-dimensional empirical affine transformation as a case study. We address the noniterative transformation for the partially and fully error-affected affine models, respectively. The study indicates that the noniterative solution exists when the...
8 citations
TL;DR: In this article, a methodology was proposed to produce continuous surfaces without inconsistent normals and minimizes holes and self-intersections, and the few intersecting triangles and holes may be quickly repaired using existing algorithms and were shown to be easily repaired.
Abstract: Light detection and ranging (LIDAR) scanners can rapidly collect high-resolution, centimeter-level-accurate point clouds representing topography, suitable for change detection if scans are repeated over time. To perform meaningful volumetric change analyses, point clouds are commonly triangulated to produce continuous, digital terrain models (DTMs). However, DTM creation methods generally require a fixed-look direction tied to a specific plane, which results in less than ideal triangulations when modeling areas with largely varying topography, such as coastal cliffs and beaches. Furthermore, for accurate volumetric change analysis, surfaces must be free of intersecting triangles, have consistent facet-normal orientations, and be free of data gaps (holes). The methodology presented herein produces continuous surfaces without inconsistent normals and minimizes holes and self-intersections. The few intersecting triangles and holes may be quickly repaired using existing algorithms and were shown to be...
7 citations
TL;DR: An efficient approach that utilizes the intensity information provided in most light detection and ranging (LIDAR) data sets for feature conjugation is proposed and illustrated that by fully exploring the existing spectral information, a reliable feature conjjugation across multipliers is illustrated.
Abstract: Feature conjugation is a major task in modern-day spatial analysis and contributes to efficient integration across multiple data sets. In this study, an efficient approach that utilizes the intensity information provided in most light detection and ranging (LIDAR) data sets for feature conjugation is proposed. First, a two-dimensional (2D) intensity map is generated based on the original intensity-coded LIDAR observables in three-dimensional (3D) space. The 2D map is further transformed into a regularly sampled image, and an image feature detection technique is subsequently applied to identify point conjugations between a pair of intensity maps. Finally, the paired conjugations in the image space are mapped backward into the LIDAR space, and the object coordinates of the conjugate points can be verified and obtained. Based on the numerical results from a real world case study, it is illustrated that by fully exploring the existing spectral information, a reliable feature conjugation across multipl...
TL;DR: This approach breaks down the connections between the stations and satellites of the DD corrections in the current NRTK methods, such that corrections can be broadcast by the base station and automatically selected and optimized by a rover during the real-time kinematic (RTK) processing when the rover is transitioning into a more favorable subnetwork configuration.
Abstract: In this paper, the network real-time kinematic (NRTK) positioning method based on undifferenced (UD) observation corrections (abbreviated as URTK) are described, in which instantaneous ambiguity resolution can be carried out within rover’s precise point positioning (PPP) software, thus achieving position solutions equivalent to NRTK. The URTK method transforms the fixed double-differenced (DD) ambiguities of the reference network into UD ambiguities. With the transformed ambiguities, the residuals of the UD observation are used for interpolating the corrections at the user side. This approach breaks down the connections between the stations and satellites of the DD corrections in the current NRTK methods, such that corrections can be broadcast by the base station and automatically selected and optimized by a rover during the real-time kinematic (RTK) processing when the rover is transitioning into a more favorable subnetwork configuration, thus avoiding ambiguity reinitialization as a result of th...
TL;DR: In this article, the authors present a simple method of finding the solution to the planar three point resection problem based on an idea of two intersecting circles, which is not new in the literature, and the points of intersection of two circles are obtained by solving a quadratic equation.
Abstract: The paper presents a simple method of finding the solution to the planar three point resection problem. The main concept leading to the solution is based on an idea of two intersecting circles (which is not new in the literature). The points of intersection of two circles (of which one solves the problem) are obtained by solving a quadratic equation. As a result of the fact that one root of the quadratic equation is known, Vieta’s formula is applied to find the other. When one of the measured angles is equal to 0 or 180°, the problem reduces to the intersection of a straight line and a circle. This also leads to a quadratic equation which is solved by Vieta’s formula. The derivation of the method is very simple (purely analytic) and free from any intermediate parameters, for example, angles, distances, or azimuths.
TL;DR: A single-frequency single-epoch GPS attitude determination method, aimed at attitude determination without the prior knowledge of measurement precision, is presented, which is a combination of an analytical resolution and the constrained integer least-squares theory.
Abstract: During attitude determination using the Global Positioning System (GPS), incomplete knowledge of the stochastic model of the observables often occurs in realistic applications, resulting in the failure of the traditional least-squares method for the Global Navigation Satellite System baseline model. This paper presents a single-frequency single-epoch GPS attitude determination method, which is aimed at attitude determination without the prior knowledge of measurement precision. The new approach is a combination of an analytical resolution and the constrained integer least-squares theory. By using the global minimizer of the fixed ambiguity objective function, our method identifies the most likely solution from all possible analytical candidates. Simulation experiments demonstrate the performance of the proposed algorithm for different noise levels and different baseline lengths. To determine the applicable scope of this scheme, the success rate gap of the least-squares method is also analyzed. Act...
TL;DR: This new method, APLAT, combines the GPS absolute-positioning method and a loop-based accumulated-solution time-relative positioning method, which means the kinematic surveying trajectory must form a loop.
Abstract: As of this writing, there are two popular methods to perform precise surveying using the single dual-frequency Global Positioning System (GPS) receiver One is the Real-Time Kinematic (RTK) technique The other is the Precise Point Positioning (PPP) technique The RTK technique requires GPS surveyors to have at least one GPS base station while the PPP technique needs a long observation period to resolve the carrier-phase ambiguities This paper proposes a new, fast method that can conduct precise kinematic surveying using a single dual-frequency GPS receiver, overcoming the aforementioned problems This new method, Absolute Plus Loop-based Accumulated-solution Time-relative (APLAT), combines the GPS absolute-positioning method and a loop-based accumulated-solution time-relative positioning method In this APLAT method, the kinematic surveying trajectory must form a loop The coordinates of the start-point of the loop can be precisely determined using the absolute positioning function of APLAT by m
TL;DR: In this article, a surveying-engineering procedure is presented for gravimetric geoid model verification along selected railway traverse lines using collocated ellipsoid and orthometric heights.
Abstract: A surveying-engineering procedure is presented for gravimetric geoid model verification along selected railway traverse lines using collocated ellipsoid and orthometric heights. The proposed method relies on (1) a tactical-grade, multisensor [Global Navigation Satellite System (GNSS)/inertial navigation system (INS)] kinematic-surveying system used to measure the ellipsoid heights along the traveled section and (2) the orthometric heights derived from the railway-line construction and/or maintenance works. Compared with the standard static GPS/leveling technique, the proposed approach produces geoid height profiles in a very short acquisition time, with dense point spacing, and in a considerably inexpensive manner. The quality of the final results reflects the accuracy of modern GNSS/INS systems and available rail-track orthometric height information. The method was applied to a long (101-km) railway traverse in central Greece using a custom-built mobile mapping system. Gravimetric geoid model verification was undertaken in an absolute and relative manner for the Earth Gravitational Model 2008 (EGM08) and 1996 (EGM96) geopotential models. Analysis of the results has demonstrated the potential of the method both in terms of efficiency and in terms of the evaluation checks performed. Based on the absolute- and relative-quality tests undertaken, the superiority of EGM08 over EGM96 is clearly evident for the tested line. Also, these results are cross compared and evaluated with the findings obtained from previous studies in Greece.
TL;DR: This case study aims to demonstrate a multi-antenna GNSS technique and quality evaluation approach that can be used to determine the attitude parameters for a moving platform and shows that the proposed approach is capable of giving efficient and reliable attitude parameter estimates independently without the need for auxiliary information.
Abstract: This case study aims to demonstrate a multi-antenna Global Navigation Satellite System (GNSS) technique and quality evaluation approach that can be used to determine the attitude parameters for a moving platform. First, considering the highly dynamic behavior of a moving platform, a noniterative parameter determination approach was introduced. A rigorous error analysis approach was then established to give explicit indications on the obtained attitude parameters. Based on the numerical results from both simulated and real datasets, it has been illustrated that the proposed approach is capable of giving efficient and reliable attitude parameter estimates independently without the need for auxiliary information. Consequently, the multi-antenna GNSS system can serve as an immediate resolution for the attitude determination of moving platforms in modern day applications.
TL;DR: In this contribution, PPP usage and the performance of these global and regional BCs are analyzed for the North American Datum of 1983 (NAD83), and the limitations of the current regional BC approach for NAD83 are identified.
Abstract: Real-time precise point positioning (PPP) is possible through the availability of the real-time satellite orbit and clock corrections to broadcast ephemeris, the real-time broadcast corrections (BCs). The real-time BCs are currently available in global as well as in regional reference frames. In this contribution, PPP usage and the performance of these global and regional BCs are analyzed for the North American Datum of 1983 (NAD83). The limitations of the current regional BC approach for NAD83 are identified and the coordinate differences it leads to compared with the traditional global BC approach are shown. Although the biases as a result of the different reference frame usage are shown to be subcentimeter, it is also shown how they can be reduced or eliminated by modifying either the PPP algorithm or the regional BC approach. Analyses were performed for three different PPP variants, a single-frequency ionosphere-free variant, a dual-frequency ionosphere-free variant, and a single-frequency ion...
TL;DR: In this paper, the authors developed a global positioning system (GPS)-based information system, which integrated six major modules to provide a real-time positioning and guidance solution for pile-driving barge control in a marine pier construction project.
Abstract: Pile positioning, for driving piles below the surface of water in a marine pier construction project, is typically a time-consuming task owing to the fact that the pile wharf is affected significantly by environmental limitation and marine meteorology. As a result, it is always a goal to minimize the positioning time while maintaining a desired level of accuracy. This study developed a global positioning system (GPS)-based information system, which integrated six major modules. This system was designed to provide a real-time positioning and guidance solution for pile-driving barge control in a marine pier construction project. In a case study, the developed system has been implemented successfully in a real project and proved this system can improve the horizontal accuracy of real-time pile positions by less than 1 cm. It also contributed to a 42% reduction in the construction time and thus an 11% reduction in the final budget. Consequently, the efficiency of a piling construction project could be improved significantly by incorporating such a system.
TL;DR: In this article, the authors classified the most common type of horizontal curves used to connect intersecting straight sections of highways and other infrastructures into three groups according to their solution type: direct analytical solutions can be easily obtained using simple algebraic operations, full analytical solutions with physical meaning are not available, and existing methods rely on a tedious trial procedure for most cases.
Abstract: The most common type of horizontal curves used to connect intersecting straight sections of highways and other infrastructures are circular curves. Given the radius and the deflection angle of a horizontal circular curve, the other curve elements can be explicitly determined. However, there are 10 practical situations in which these parameters are unknown, and they have to be determined from two other given elements. In the present paper, these cases are classified into three groups according to their solution type. In the first group, direct analytical solutions can be easily obtained using simple algebraic operations. In the second group, full analytical solutions with physical meaning are not available, and in the third group, existing methods rely on a tedious trial procedure for most cases. The paper develops noniterative exact solutions for the two cases of the second group and noniterative near-exact solutions for the four cases of the third group. The proposed near-exact solutions for the ...
TL;DR: Nobody envisioned in 1955, when Eugene Garfield introduced the concept of impact factor as ametric tomeasure the average number of citations published in a particular scientific journal, that this simple mathematically based idea would eventually be completely blown out of proportion.
Abstract: Nobody envisioned in 1955, when Eugene Garfield introduced the concept of impact factor (IF) as ametric tomeasure the average number of citations published in a particular scientific journal (Garfield 1955), that this simple mathematically based idea would eventually be completely blown out of proportion. For those unfamiliar with the terminology, the definition of IF for a specific journal is computed according to the following straightforward equation: