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  • 1.
    Alizadeh Khameneh, Mohammad Amin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning. WSP Civils, Department of Geographic Information and Asset Management.
    Horemuž, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Jensen, Anna B. O.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Vium Andersson, Johan
    WSP Civils, Department of Geographic Information and Asset Management.
    Optimal Vertical Placement of Total Station2018In: Journal of Surveying Engineering, ISSN 0733-9453, E-ISSN 1943-5428Article in journal (Refereed)
    Abstract [en]

    When using the free station method, a Total Station (TS) is established by performing distance and angle observations toward a number of Control Points (CPs). The quality of the establishment is crucial for the quality of subsequent measurements. The optimal horizontal location of the TS has been investigated in previous studies. Even the vertical precision is important in many applications, especially with significant height variations. Therefore in this paper, we focus on the optimality of vertical location of the TS. As an optimality criterion, the sum of TS coordinates and orientation variances is used. To investigate the optimization problem, an analytical as well as a trial and error method is developed. Both methods showed that the height component has no significant influence on the optimal vertical placement of the TS. Inspection of results from the trial and error method, where the CPs are moved in different height layers, indicates differences in the height uncertainty of the establishment in micrometer range, which is negligible for most engineering applications.

  • 2.
    Alizadeh Khameneh, Mohammad Amin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning. WSP Civils, Department of Geographic Information and Asset Management.
    Jensen, Anna B. O.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Horemuž, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Andersson, Johan Vium
    WSP Civils, Department of Geographic Information and Asset Management.
    Investigation of the RUFRIS Method with GNSS and Total Station for Leveling2017Conference paper (Refereed)
    Abstract [en]

    The establishment of leveling benchmarks for performing geodetic measurements, for instance in construction works, is usually costly and laborious due to a mass of field works in transferring the height from nearby known benchmarks. In this study, a real-time updated free station (RUFRIS) method is investigated to be used as an alternative approach for the traditional leveling. The coordinates of a RUFRIS station are determined by establishing a total station on the point, and performing a free-station by observing some points with both Real-Time Kinematic (RTK) GNSS and total station distance and direction observations. The study is conducted based on data from the East Link project in Sweden, where a 150 km long high-speed railway is to be constructed. The results show a standard deviation of 7 mm between the RUFRIS and leveling heights in this project and imply the feasibility of replacing the traditional leveling methods with RUFRIS in projects with low accessibility to benchmarks.

  • 3.
    Eshagh, Mehdi
    et al.
    Univ West, Dept Engn Sci, Trollhattan, Sweden..
    Johansson, Filippa
    Univ West, Dept Engn Sci, Trollhattan, Sweden..
    Karlsson, Lenita
    Univ West, Dept Engn Sci, Trollhattan, Sweden..
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Geodesy and Satellite Positioning.
    A case study on displacement analysis of Vasa warship2018In: Journal of Geodetic Science, ISSN 2081-9919, E-ISSN 2081-9943, Vol. 8, no 1, p. 43-54Article in journal (Refereed)
    Abstract [en]

    Monitoring deformation of man-made structures is very important to prevent them from a risk of collapse and save lives. Such a process is also used for monitoring change in historical objects, which are deforming continuously with time. An example of this is the Vasa warship, which was under water for about 300 years. The ship was raised from the bottom of the sea and is kept in the Vasa museum in Stockholm. A geodetic network with points on the museum building and the ship's body has been established and measured for 12 years for monitoring the ship's deformation. The coordinate time series of each point on the ship and their uncertainties have been estimated epoch-wisely. In this paper, our goal is to statistically analyse the ship's hull movements. By fitting a quadratic polynomial to the coordinate time series of each point of the hull, its acceleration and velocity are estimated. In addition, their significance is tested by comparing them with their respective estimated errors after the fitting. Our numerical investigations show that the backside of the ship, having highest elevation and slope, has moved vertically faster than the other places by a velocity and an acceleration of about 2 mm/year and 0.1 mm/year(2), respectively and this part of the ship is the weakest with a higher risk of collapse. The central parts of the ship are more stable as the ship hull is almost vertical and closer to the floor. Generally, the hull is moving towards its port and downwards.

  • 4.
    Gajdamowicz, Krzysztof
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Laser scanning and 3D Modeling of War Ship Vasa2005Conference paper (Refereed)
  • 5.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatik och Geodesi.
    Car collision warning system based on RTK GPS.2008In: FIG Working Week 2008 - Integrating Generations and FIG/UN-HABITAT Seminar – Improving Slum Conditions through Innovative Financing / [ed] Stig Enemark, 2008Conference paper (Refereed)
    Abstract [en]

    Many serious traffic accidents happen when a car drives over to the opposite lane. Aneffective way to prevent such accidents is to mount a barrier between opposite drivingdirections in form of cable fence. This is a quite expensive solution, which is not applicableon all roads. Therefore it is desirable to find alternative methods.One possible alternative is to use GPS, namely a RTK method (Real Time Kinematics), whichis capable to deliver sufficiently accurate position to compute if the car drives in correct laneand if the distance to the road edge is safe. The basic concept of the warning system is toplace the actual position of the car into a precise road model and to compute if the car isoutside or on its way out of the correct lane. If so, the system will warn the driver.This paper describes a prototype of such a warning system. The system was tested on 10 kmlong road section. The car performed 38 intentional manoeuvres that should trigger alarm.The evaluation of the tests was done visually, using video sequence synchronised with thegraphical output from the warning system. 32 manoeuvres were correctly alarmed by thesystem. The system issued 32 false alarms during 40 minutes driving. However, most of themhad only short duration, less than 0.2 s.

  • 6.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatik och Geodesi.
    Citynavigering - metoder och infrastruktur2010Conference paper (Other (popular science, discussion, etc.))
  • 7.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatics (closed 20110301).
    Infrastructure for navigation in urban and indoor araes-feasibility sudy2009Report (Other (popular science, discussion, etc.))
  • 8.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatik och Geodesi.
    Realtidsuppdaterad fristation: Kontrollerbarhetsanalys2011Report (Other academic)
  • 9.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatik och Geodesi.
    Realtidsuppdaterad fristation: Korrelationsanalys2011Report (Other academic)
  • 10.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Realtidsuppdaterad fristation: Precisionsanalys2008Report (Other academic)
  • 11.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Tröghetsnavigering för mätning2006Conference paper (Other (popular science, discussion, etc.))
  • 12.
    Horemuz, Milan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatik och Geodesi.
    Anderson, Johan
    WSP.
    Analysis of the precision in free station establishment by RTK GPS2011In: Survey Review, ISSN 1752-2706, Vol. 43, no 323, p. 679-686Article in journal (Refereed)
    Abstract [en]

    The coordinates and orientation of a total station can be determined by using common points, i.e. pointssurveyed both by total station and RTK (Real Time Kinematics) GPS. In this paper we use a trial anderror method to analyse how the number and distribution of common points affects the precision of thetotal station establishment. It was found that a reasonable number of common points is 10 – 30, and thatthese should be distributed around the total station on a half circle. The radius of the half circle doesnot significantly affect precision of horizontal and vertical positions; it affects only orientationprecision. Therefore we suggest locating most of the common points close to the total station and a fewof them at longer distance.

  • 13.
    Horemuz, Milan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Andersson, Johan Vium
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Polynomial interpolation of GPS satellite coordinates2006In: GPS Solutions, ISSN 1080-5370, E-ISSN 1521-1886, Vol. 10, no 1, p. 67-72Article in journal (Refereed)
    Abstract [en]

    This article describes an algorithm for polynomial interpolation of GPS satellite coordinates and its implementation in MATLAB. The algorithm is intended for realtime processing software and computes the position and velocity of GPS satellites from both broadcast and precise ephemerides. Tests with different orders of polynomials, and with different time spans used for polynomial fitting, show suitable settings with respect to the required interpolation precision.

  • 14.
    Horemuz, Milan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Gajdamiwicz, Krzysztof
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Integration of digital camera with INS2005Conference paper (Refereed)
  • 15.
    Horemuz, Milan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Jansson, Patric
    Optimal placering av en totalstation2016In: SINUSArticle in journal (Other (popular science, discussion, etc.))
  • 16.
    Horemuz, Milan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Jansson, Patric
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Optimum Establishment of Total Station2016In: Journal of Surveying Engineering, ISSN 0733-9453, E-ISSN 1943-5428, Vol. 143, no 2Article in journal (Refereed)
    Abstract [en]

    At least two control points (CPs) must be available to determine the position and orientation of a total station (TS). This paper analyzes the optimum horizontal location of the TS with respect to the CPs and answers the question: What is the best location of the TS with respect to the CPs if the goal is to determine the coordinates of the TS and detail points (DPs) as precisely as possible? The optimality is based on the uncertainty of the horizontal coordinates of the TS and of the points measured from it, as well as on the uncertainty of the TS orientation. The investigation of this optimality problem was performed both analytically and by the trial-and-error method. It was found that the optimum location of TS is in the center of gravity of all CPs. For a given configuration of the control and DPs, the location of the TS does not influence significantly the positional uncertainty of the surveyed DPs.

  • 17.
    Horemuz, Milan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Jensen, Anna B. O.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Analysis of temporal correlation in free station establishment with RTK GNSS2016In: European Journal of Navigation, ISSN 1571-473XArticle in journal (Refereed)
  • 18.
    Horemuz, Milan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Yueming, Zhao
    Motion of moving camera from point matches: comparison of two robust estimation methods2014In: IET Computer Vision, ISSN 1751-9632, E-ISSN 1751-9640, Vol. 8, no 6, p. 682-689Article in journal (Refereed)
    Abstract [en]

    A robust estimation method, Balanced Least Absolute Value Estimator (BLAVE), is introduced and compared with thetraditional RANdom SAmple Consensus (RANSAC) method. The comparison is performed empirically by applying bothestimators on the camera motion parameters estimation problem. A linearised model for this estimation problem is derived.The tests were performed on a simulated scene with added random noise and gross errors as well as on actual images takenby a mobile mapping system. The greatest advantage of BLAVE is that it processes all observations at once as well as itsmedian-like property: the estimated parameters are not influenced by the size of the outliers. It can tolerate up to 50% outliersin data and still produce accurate results. The greatest disadvantage of RANSAC is that the results are not repeatable becauseof the random sampling of data. Moreover, the results are less accurate, because RANSAC generally does not produce a‘best-fit’ parameter estimation. The number of trials, which must be tested by RANSAC to find a reasonable solution,depends on the portion of outliers in data. The computational time for BLAVE does not depend on the portion of outliers inthe observations, but it grows with the number of observations, same as RANSAC.

  • 19.
    Horemuž, Milan
    et al.
    KTH, Superseded Departments, Geodesy and Photogrammetry.
    Sjöberg, Lars Erik
    KTH, Superseded Departments, Infrastructure.
    Rapid GPS ambiguity resolution for short and long baselines2002In: Journal of Geodesy, ISSN 0949-7714, E-ISSN 1432-1394, Vol. 76, no 07-jun, p. 381-391Article in journal (Refereed)
    Abstract [en]

    A method of quick initial carrier cycle ambiguity resolution is described. The method applies to high-quality dual-band global positioning system observations. Code measurements on both frequencies must be available. The rapidity of the method is achieved through smoothing pseudoranges by phase observables and forming linear combinations between the phase observables. Two cases are investigated. Case 1: ionospheric bias is neglected (short distances); and case 2: the bias is taken into account (longer distances, more than, say, 10 km). The method was tested on six baselines, from 1 to 31 km long. In most cases, single-epoch ambiguity resolution was achieved.

  • 20.
    Håkansson, Martin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning. Lantmäteriet.
    Jensen, Anna B. O.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Gunnar, Hedling
    Lantmäteriet.
    Review of code and phase biases in multi-GNSS positioning2017In: GPS Solutions, ISSN 1080-5370, E-ISSN 1521-1886, Vol. 21, no 3, p. 849-860Article in journal (Refereed)
    Abstract [en]

    A review of the research conducted until present on the subject of Global Navigation Satellite System (GNSS) hardware-induced phase and code biases is here provided. Biases in GNSS positioning occur because of imperfections and/or physical limitations in the GNSS hardware. The biases are a result of small delays between events that ideally should be simultaneous in the transmission of the signal from a satellite or in the reception of the signal in a GNSS receiver. Consequently, these biases will also be present in the GNSS code and phase measurements and may there affect the accuracy of positions and other quantities derived from the observations. For instance, biases affect the ability to resolve the integer ambiguities in Precise Point Positioning (PPP), and in relative carrier phase positioning when measurements from multiple GNSSs are used. In addition, code biases affect ionospheric modeling when the Total Electron Content is estimated from GNSS measurements. The paper illustrates how satellite phase biases inhibit the resolution of the phase ambiguity to an integer in PPP, while receiver phase biases affect multi-GNSS positioning. It is also discussed how biases in the receiver channels affect relative GLONASS positioning with baselines of mixed receiver types. In addition, the importance of code biases between signals modulated onto different carriers as is required for modeling the ionosphere from GNSS measurements is discussed. The origin of biases is discussed along with their effect on GNSS positioning, and descriptions of how biases can be estimated or in other ways handled in the positioning process are provided.

  • 21. Mill, Tarvo
    et al.
    Ellmann, Artu
    Aavik, Andrus
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Sillamaee, Sven
    Determining Ranges and Spatial Distribution of Road Frost Heave by Terrestrial Laser Scanning2014In: Baltic Journal of Road and Bridge Engineering, ISSN 1822-427X, E-ISSN 1822-4288, Vol. 9, no 3, p. 225-234Article in journal (Refereed)
    Abstract [en]

    The technology of terrestrial laser scanning has evolved rapidly in recent years and it has been used in various applications, including monitoring vertical and horizontal displacements of constructions but significantly less in road frost heave assessment. Frost heave is categorised as one of the main causes of pavement surface damage in seasonal frost regions. Frost heave occurs in wintertime and in early spring at the freezing process of the ground supported structures such as roads. The major change in the structure is the increase of soil volume due to freezing of its water content. This contribution assesses vertical displacements caused by frost heave on a road using novel terrestrial laser scanning technology. The study emphasises on benefits using the technology in determining accurate magnitudes and spatial distribution of frost heave of roads. The results of case study revealed uneven spatial distribution of frost heave, which may also be an evidence of relatively poor road design quality. Therefore it is also advisable using terrestrial laser scanning in applications such as quality assessment of existing roads and in the pre-reconstruction design stage for detecting any frost heave sensitive areas in existing embankments.

  • 22.
    Mill, Tarvo
    et al.
    Tallin University of Technology.
    Ellmann, Artu
    Tallin University of Technology.
    Kiisa, Martti
    University of Applied Sciences, Tallin.
    Idnurm, Juhan
    Tallin University of Technology.
    Idnurm, Siim
    Tallin University of Technology.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Aavik, Andrus
    Tallin University of Technology.
    Geodetic monitoring of bridge deformations occurring during static load testing2015In: Baltic Journal of Road and Bridge Engineering, ISSN 1822-427X, E-ISSN 1822-4288, Vol. 10, no 1, p. 17-27Article in journal (Refereed)
    Abstract [en]

    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 m(2) 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.

  • 23.
    Reshetyuk, Yuriy
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Horemuž, Milan
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Sjöberg, Lars Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Determination of the optimal diameter for spherical targets used in 3D laser scanning2005In: Survey review - Directorate of Overseas Surveys, ISSN 0039-6265, E-ISSN 1752-2706, Vol. 38, no 297, p. 243-253Article in journal (Refereed)
    Abstract [en]

    An efficient use of 3D laser scanning requires the development of standardized calibration procedures available to the users. This is part of the research recently started at the Royal Institute of Technology; (KTH) in Stockholm and the establishment of a calibration field is planned, which may he realized by means of spherical targets. An approach for the rigorous theoretical determination of the optimal diameter for those targets is presented. It is based on the least-squares adjustment according to the mixed model when observations are combined with the unknown parameters. The weight function was chosen based on the Lambertion standard reflectance model. The computations were performed for the scanners Leica HDS 3000 and Imager 5003 (Zoller+Frohlich) for two cases - with fixed and free (to be estimated in the adjustment) target diameter. The value of 14 cm has been obtained for the optimal diameter, which is independent on the range to the scanner.

  • 24.
    Shirazian, Masoud
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatik och Geodesi.
    Sjöberg, Lars E.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatik och Geodesi.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatik och Geodesi.
    A remark on the GNSS differenced phase ambiguity parameters2011In: Acta Geodaetica et Geophysica Hungarica, ISSN 1217-8977, E-ISSN 1587-1037, Vol. 46, no 4, p. 431-440Article in journal (Refereed)
    Abstract [en]

    In the global navigation satellite system (GNSS) carrier phase data processing, cycle slips are limiting factors and affect the quality of the estimators in general. When differencing phase observations, a problem in phase ambiguity parameterization may arise, namely linear relations between some of the parameters. These linear relations must be considered as additional constraints in the system of observation equations. Neglecting these constraints, results in poorer estimators. This becomes significant when ambiguity resolution is in demand. As a clue to detect the problem in GNSS processing, we focused on the equivalence of using undifferenced and differenced observation equations. With differenced observables this equivalence is preserved only if we add certain constraints, which formulate the linear relations between some of the ambiguity parameters, to the differenced observation equations. To show the necessity of the additional constraints, an example is made using real data of a permanent station from the network of the international GNSS service (IGS). The achieved results are notable to the GNSS software developers.

  • 25.
    Sjöberg, Lars
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Walyeldeen, Hassan Edres
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Estimation of crustal motions at the permanent GPS station SVEA, Antarctica, from 2005 to 20092011In: Journal of Geodetic Science, ISSN 2081-9919, E-ISSN 2081-9943, Vol. 1, no 3Article in journal (Refereed)
    Abstract [en]

    In November 2004 the permanent GPS station SVEA (Latitude: 74°34' 34" S, Longitude: 11° 13' 31" W, Height 1261.2 m) was installed in Drottning Maud's Land, Antarctica. The main aim of this paper is to evaluate the collected data for on-going crustal motions. About 40% ("3-days weekly") of the continuous four years GPS data from 2005 to 2009 was processed together with the simultaneous data of five IGS reference stations using Bernese GPS software V 5.0. A linear regression analysis was used to estimate the linear motion of the station, yielding the estimated velocities' components (in mm/year) of 6.6± 0.4 North, -1.4 ± 0.2 East and 4.4 ± 0.6 Up. Although all components appear highly significant, the abnormal development of the E-W component needs further analyses. Post-glacial rebound is estimated to contribute only to 0.2-0.3 mm/yr (James and Ivin, 1998) of the vertical uplift rate, suggesting that the observed vertical motion mainly has another origin, possibly tectonic. The crustal motion results should be regarded as preliminary, and they need both further data and analyses to be confirmed.

    It is also concluded that the remote continuously running GPS station SVEA works well after more than five years of operation with only annual checks and data retrieval in the harsh environment of Antarctica.

  • 26.
    Uggla, Gustaf
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Geodesy and Satellite Positioning.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Geodesy and Satellite Positioning.
    Geographic capabilities and limitations of Industry Foundation Classes2018In: Automation in Construction, ISSN 0926-5805, E-ISSN 1872-7891, Vol. 96, p. 554-566Article in journal (Refereed)
    Abstract [en]

    Infrastructure design is conducted in a 3D Cartesian coordinate system with the assumption that the Earth is flat and that the scale is constant over the entire project area. Map projections are commonly used to georeference the designed geometries before constructing them on the surface of the Earth. The scale in a map projection varies depending on the position in the map plane, which leads to scale distortions between the designed geometries and the geometries staked out for construction. These distortions are exaggerated for large longitudinal projects such as the construction of roads and railroads because the construction site spans a larger area. Building Information Modeling (BIM) is increasing in popularity as a way to manage information within a construction project. Its use is more widespread in the building industry, but it is currently being adopted by the infrastructure industry as well. The open BIM standard IFC (Industry Foundation Classes) has recently developed support for alignment geometries, and full support for disciplines such as road and railroad construction is underway. This study tests whether the current IFC standard can facilitate georeferencing with sufficiently low distortion for the construction of infrastructure. This is done by performing georeferencing using three different methods, all using the information provided in the IFC schema, and by calculating the scale distortions caused by the different methods. It is concluded that the geographic capabilities of the IFC schema could be improved by adding a separate scale factor for the horizontal plane and support for object-specific map projections.

  • 27.
    Uggla, Gustaf
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Geodesy and Satellite Positioning.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Geodesy and Satellite Positioning.
    Georeferencing Methods for IFC2018In: Proceedings - 2018 Baltic Geodetic Congress, BGC-Geomatics 2018, Institute of Electrical and Electronics Engineers Inc. , 2018, p. 207-211Conference paper (Refereed)
    Abstract [en]

    Building Information Modelling (BIM) is becoming a standard tool for information management throughout the life cycle of a construction project. Elements in BIM are designed in a Cartesian coordinate system (Engineering system) with no direct relation to the project's geographic location. Accurate georeferencing of BIM data is required both for construction and integration with Geographic Information Systems (GIS), as improperly treated or neglected scale distortions can lead to costly delays in construction as problems requiring ad hoc solutions may arise on site Industry Foundation Classes (IFC) is an open BIM standard developed by buildingSMART, and the current version IFC 4 has recently been extended with IFC Alignment, which includes support for alignment geometries used for infrastructure design. This paper investigates the geographic capabilities of IFC 4 and its extension IFC Alignment. The study identifies a lack of support for non-uniform scale factors and object-specific map projections as the largest weaknesses.

  • 28.
    Zhao, Yueming
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Horemuz, Milan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Sjöberg, Lars E.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Stochastic modelling and analysis of IMU sensor errors2011In: Archives of Photogrammetry, Cartography and Remote Sensing, ISSN 2083-2214, Vol. 22, p. 437-449Article in journal (Refereed)
    Abstract [en]

    The performance of a GPS/INS integration system is greatly determined by the ability of stand-alone INS system to determine position and attitude within GPS outage. The positional and attitude precision degrades rapidly during GPS outage due to INS sensor errors. With advantages of low price and volume, the Micro Electrical Mechanical Sensors (MEMS) have been wildly used in GPS/INS integration. Moreover, standalone MEMS can keep a reasonable positional precision only a few seconds due to systematic and random sensor errors. General stochastic error sources existing in inertial sensors can be modelled as (IEEE STD 647, 2006) Quantization Noise, Random Walk, Bias Instability, Rate Random Walk and Rate Ramp. Here we apply different methods to analyze the stochastic sensor errors, i.e. autoregressive modelling, Gauss-Markov process, Power Spectral Density and Allan Variance. Then the tests on a MEMS based inertial measurement unit were carried out with these methods. The results show that different methods give similar estimates of stochastic error model parameters. These values can be used further in the Kalman filter for better navigation accuracy and in the Doppler frequency estimate for faster acquisition after GPS signal outage.

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