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  • 1. Andersson, Anders
    et al.
    Holmsten, Magnus
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Mätteknik för processindustrin2017 (oppl. 5)Bok (Annet vitenskapelig)
    Abstract [sv]

    Hur varmt är det i tanken? Vilket tryck ger pumpen? Det är två exempel på frågor som kan besvaras med processmätteknik.Att mäta är att veta, sägs det, men det gäller ocksåatt veta hur bra man mäter! Felaktiga mätresultat skaparproblem, osäkerhet och kan rent av vara farliga.I den här boken får du hjälp att undvika mätfel, du fårlära dig om olika mätprinciper och hur mätare av olika slagbäst används och monteras. Främst handlar det om temperatur,tryck, flöde och nivå men även annat som finns i enprocessindustri. Du får kunskap om kalibrering, spårbarhetoch mätosäkerhet, och samtidigt om saker runt omkringmätinstrumenten, till exempel CE-märkning, elstörningar,explosionsskydd, skrivregler, signalöverföring, standardermed mera

    Innehållsförteckning:  1: Mätteknik 2: Lästips – Gör så här 3: Mått i historien 4: CE-märkning 5: SI-systemet 6 :Signalöverföring 7: Säkerhet 8: Mätosäkerhet A 9: Fysik och matematik 10: Mättekniska begrepp 11: Temperaturmätning 12: Tryckmätning 13: Flödesmätning 14:Nivåmätning 15: Värmemätning 16: Vakter och larm 17:Serviceinstrument 18:Konduktivitetsmätning 19: pH-mätning 20: Densitetsmätning 21: Vägning 22: Fuktmätning 23: Mätosäkerhet B 24: Kalibrering 25: Pumpar och ventiler 26: Rörledningar 27: Mätosäkerhet C 28: Tabeller 29:Index

  • 2.
    Andersson, Bengt-Olof
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Eklund, Gunnar
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Bergsten, Tobias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Calibration of Gain Ratios on nV-Meters with the Reference Step Method2018Inngår i: CPEM 2018 - Conference on Precision Electromagnetic Measurements, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Reference Step Method for calibrators can be modified for calibration also of the gain ratios on a meter. The method has earlier been evaluated in the range 100 mV-1000 V on DMM HP 3458A1 and shows that an accuracy of typically < ± 0.2 μ V/V could be obtained. We have investigated the performance of the method when calibrating ratios in the range 1 mV-100 mV on two common nV-meters. In our comparisons with the Josephson Voltage Standard the differences are within ± ± 12μ V/V at the ratio 10m V:1mV and within ± ± 1.3μ V/V at 100mV:10mV.

  • 3.
    Arrhenius, Karine
    et al.
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Fischer, Andreas
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Büker, Oliver
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Methods for sampling biogas and biomethane on adsorbent tubes after collection in gas bags2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 6, artikkel-id 1171Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biogas is a renewable energy source with many different production pathways and numerous excellent opportunities for use; for example, as vehicle fuel after upgrading (biomethane). Reliable analytical methodologies for assessing the quality of the gas are critical for ensuring that the gas can be used technically and safely. An essential part of any procedure aimed at determining the quality is the sampling and transfer to the laboratory. Sampling bags and sorbent tubes are widely used for collecting biogas. In this study, we have combined these two methods, i.e., sampling in a gas bag before subsequent sampling onto tubes in order to demonstrate that this alternative can help eliminate the disadvantages associated with the two methods whilst combining their advantages; with expected longer storage stability as well as easier sampling and transport. The results of the study show that two parameters need to be taken into account when transferring gas from a bag on to an adsorbent; the water content of the gas and the flow rate used during transfer of the gas on to the adsorbent. © 2019 by the authors.

  • 4.
    Arrhenius, Karine
    et al.
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Karlsson, Anders
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Hakonen, Aron
    Ohlson, Lars
    Fordonsgas Sverige AB, Sweden.
    Yaghooby, Haleh
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Büker, Oliver
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Variations of fuel composition during storage at Liquefied Natural Gas refuelling stations2018Inngår i: Journal of Natural Gas Science and Engineering, ISSN 1875-5100, E-ISSN 2212-3865, Vol. 49, s. 317-323Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Liquefied Natural Gas (LNG) and Liquefied Biogas (LBG) utilization within the heavy duty transport sector is today a sustainable alternative to the use of oil. However, in spite of the high degree of insulation in the storage tank walls, it is impossible to fully avoid any net heat input from the surroundings. Due to some degree of vaporization this results in variation in gas composition during storage at refuelling stations, potentially leading to engine failures. Within this study, a vaporizer/sampler has been built and tested at a station delivering liquefied biomethane (LBG) and occasionally; such in this case, LNG to heavy and medium duty trucks. The vaporizer/sampler has then been used to study the variation of the LNG composition in the storage tank during a two weeks period. The results clearly underline a correlation between the gas phase and the liquid phase as the concentration changes follow the same trend in both phases. Two opposite effects are assumed to influence the concentration of methane, ethane and propane in the liquid and in the gas phase. On one hand, because of the probable presence of not fully mixed layers in the storage tank and due to vehicles being refuelled, both liquid and gas phases are enriched in methane at the expense of ethane and propane. On the other hand, due to boil-off effect towards the end of the storage period, both liquid and gas phases are enriched in ethane and propane at the expense of methane.

  • 5.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Absolute calibration of a 100 KV DC divider1996Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An absolute determination of the ratio of a 100 kV DC divider has been made. A new Zener device that has recently become available has been used in a step-up mode to obtain the divider ratio. The uncertainty of the determination is 5.5 ppm.

  • 6.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Achievable Accuracy in Industrial Measurement of Dissipation Factor of Power Capacitors2018Inngår i: NCSLI Measure, ISSN 1931-5775, Vol. 12, nr 1, s. 34-41Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Modern dielectrics used in power capacitors can exhibit a dissipation factor lower than 0.005 %, which approaches the limits of presently available measurement techniques. This article reviews techniques, apparatus, and available calibration services for dissipation factor with regard to lowest achievable uncertainties. It is shown that further metrological advances are necessary to lower uncertainty in the measurement to levels at least five times less than presently achievable, in order to ensure traceable and quality-assured measurement of modern dielectrics with such low dissipation factors

  • 7.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Influence of coaxial cable on response of high-voltage resisitive dividers2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An effort is pursued by several European National Measurement Institutes to lower the uncertainties in calibration of UHV measuring systems for lightning impulse. To this end, several reference dividers are investigated as regards their accuracy both for amplitude and for time parameters. During these investigations a deterioration of step response was identified when longer coaxial cables were inserted in the measuring circuit. The measured front time T1 was also affected, in one observed case by 2.5 % elongation of front time as another 25 m cable was inserted. Compared to the intention to calibrate front time measurement to better than 5 % uncertainty for front time, this contribution must be well known, or preferably be eliminated. This paper presents the experimental findings from these investigations. The investigated cables included selected coaxial, tri-axial, and cables with a corrugated screen. The effect of cable length was also studied. The influence was first discovered when applying a very fast step (rise-time < 4 ns) to the high voltage arm of a resistive divider and convolution of this step with the time derivative of an ideal lightning impulse with 0.84/60 µs impulse. The calculated output was analysed with IEC 61083 compliant software to evaluate the front time. Subsequently, these analyses have been augmented by additional comparative measurements where two reference dividers were connected to the same impulse generator, and varying the cable length of one of them. The summarized changes in front time calculated for different combinations of cable and impulse voltage dividers are shown and discussed. It is noted that a change in T1 error depends both on length of cable and its type. The results show that non-negligible front time errors may be introduced when the cable length is increased. To support these findings, further tests have been carried out with two reference impulse dividers connected in standard calibration configuration in accordance with IEC 60060-2. One divider was used as reference, while the cable for the other was varied. In this way, the change of error between configurations could be measured. A theoretical study has also been performed, calculating the distortion of a lightning impulse on a coaxial cable. The results agree qualitatively with experiments, but the detailed results show discrepancies that need further investigation.

  • 8.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Bergman, Sixten
    Consultant, Rönnvägen 1 A, 507 71 Gånghester, Sweden.
    Hoffmann, Christian
    Baur Gmbh, Austria.
    Paulus, Eberhard
    Baur Gmbh, Austria.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Traceable measurement of dielectric dissipation factor at Very Low Frequency2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Very Low Frequency (VLF) tests are often used for after-laying tests of power cables since the reactive power demand is much lower at VLF than at 50 Hz. In order to augment the usefulness of the test, it is often complemented by a measurement of dielectric dissipation factor (tan ), where the acceptance of the tested object is based on this measurement. A traceability chain for dissipation factor at high voltage and very low frequency has as yet not been recognized by the International Bureau of Weights and Measures (BIPM), which results in difficulties to prove the quality of the measurement. The measurement is complicated by the limited range of the current in the test object that can be resolved by available high voltage test equipment, thus limiting the possible choices of reference systems. A novel reference measuring system that can fulfil these needs has been developed at SP Technical Research Institute of Sweden in the capacity as National Measurement Institute. The traceability of the system to National Standards of Measurement is ensured by careful scientific work and analyses. This measuring system has the ability to measure dissipation factor at 0.1 Hz in the voltage range from 0.5 kV up to 50 kV with an uncertainty better than 0.004 %.

  • 9.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Hällström, Jari
    VTT-MIKES, Finland.
    Evaluation of step response of transient recorders for lightning impulse2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    High voltage equipment will be subjected to several types of electrical stress during operation. A battery of factory tests is defined to ensure that the equipment will perform satisfactorily in service. One of the crucial tests is to apply a simulated lighting impulse as standardised to a double-exponential impulse with at front time of 1.2 µs (± 30 %) and a time to half value of 50 µs (± 20 %). Although this wave-shape only approximates natural lightning, there is a solid body of experience within industry, proving that reliability of equipment in service is adequately proven by the standard waveform. It is however crucial for consistency of results that the both voltage level and wave-shape are correctly measured. This paper discusses the requirements and performance of the recording instruments used, leaving the properties of high voltage impulse dividers outside the discussion. The requirements for the recording instrument – transient recorder – are given in IEC 61083-1. The standard provides requirements for, and/or tests to verify, that the recorder has moderately fast response, fast settling time, high resolution, linearity under dynamic conditions, high accuracy and reasonably low internal noise. This is partly in contrast to major trends in transient recorder development, where fast sampling and fast step response are prioritized ahead of high accuracy and fast settling without creeping response. We have therefore evaluated several commercially available recorders in order to find one with respectively flat and reasonably fast step response. In this campaign, a proprietary step generator based on the use of a mercury reed relay has been used. Evaluation of this device is submitted to ISH 2017. It has been found that the measured flatness of the step response directly after the step is a good first indicator of the performance of the transient recorder. This is identified in IEC 61083-1 clauses 1.5.2 and 1.5.3, as a requirement on stability of the recorded step from 0.5 T1min to T2max. For lightning impulse this means from 0.42 µs to 60 µs. For approved transient recorders the requirement is to be within 1 %. For reference transient recorders, a limit of not more than 0.5 % should be applied. Further proof of the accuracy of the transient recorder can be achieved by convolution of an ideal waveform with the recorded step response and analysing the resulting curve with lightning impulse parameter software. A third possibility is to make direct calibration of the transient recorder, using a calculable impulse calibrator. Several state-of-art transient recorders have been evaluated and the results show that only a few are suited for measurement of lightning impulse. Also, the variation of the performance between the ranges and channels of one instruments are significantly large. Both direct assessment of step response as well as result of convolution with a theoretical 0.84/50 µs impulse will be reported. The agreement with results obtained with a calculable impulse calibrator will be illustrated.

  • 10.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Nordlund, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Characterisationat low voltage of two reference lightning impulse dividers2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An effort is pursued by several European National Measurement Institutes to lower the uncertainties in calibration of UHV measuring systems for lighting impulse. To this end, several reference dividers are investigated as regards their accuracy both for amplitude and for time parameters. At SP - RISE Research Institutes of Sweden, a 500 kV resistive reference divider has been in use since 2000. Additionally an 800 kV resistive divider is investigated as a possible reference divider for UHV lightning impulse measuring systems. The best uncertainty for the 500 kV reference measuring system is 1 % for voltage amplitude and 3 % for time parameters. The present work aims at lowering these uncertainties by means of better characterisation and evaluation of the possibilities to apply corrections for known errors. The scale factor and dynamic behaviour of a resistive divider can be conveniently determined at low voltage and frequency. Further experiments such as linearity tests and augmented by scientific work is needed to ascertain the performance at high voltage. Step response plays a major role in the characterisation of dividers, and in this work much effort has gone into gathering step responses and evaluating them for various circuit layouts to characterise the variation of the step response due to circuit dimensions and diverse proximity effects. The step applied to the divider is generated by a mercury wetted relay based step generator with an output voltage of 200 V. The step rise-time is a few ns, and thus appreciably faster than the response of the divider. Apart from inspection of the step response itself, evaluation of measurement errors is performed by convolving an ideal curve with the step response of the divider, including its transmission cable. The convolved signal is evaluated with impulse evaluation software and the parameters compared to the ideal input. The difference is a measure of the errors introduced by the divider. This procedure follows IEC 60060-2: 2010.

  • 11.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Nordlund, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Meisner, Johann
    Physikalisch-Technische Bundesanstalt PTB, Germany.
    Passon, Stephan
    Physikalisch-Technische Bundesanstalt PTB, Germany.
    Hällström, Jari
    VTT-MIKES, Finland.
    Lehtonen, Tapio
    VTT-MIKES, Finland.
    Characterization of a fast step generator2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Lighting impulse measurements are made as a matter of routine in high voltage testing of high-voltage electrical equipment. The test is often decisive for acceptance of the equipment under test, and consequently proper and precise calibration of the measuring system is needed. The present work centres on the need to quantify the errors of reference measuring systems for lightning impulse. Scale factor determination at low frequency (or DC) is the starting point for this determination. The extrapolation from this frequency domain to the domain where microsecond pulses must be faithfully captured requires application either of methods in the frequency domain or in the time domain. Radio frequency measurements are only well defined for coaxial structures and at impedances in the range of 50 O or thereabouts, making them difficult to apply to the large structures of high-voltage measuring systems. The converse method in the time domain is to apply a Dirac impulse to the system and calculate the response to an assumed input signal by convolution. A true Dirac pulse is not readily available and in practice the applied pulse is a step voltage, which is then derived with respect to time and convolved with the applied signal to obtain the response of the measuring system. The step generator used for this purpose should have very fast front without oscillations. The intent is to achieve a close approximation of an ideal step function, which when derived with respect to time, yields the impulse response of a tested system. A necessary prerequisite is that the step is much steeper than the lightning impulse, and is flat after the step on times much longer than the impulse. The ideal switch element in such a step generator should have infinite resistance and zero capacitance in the off-state, very fast switching to on-state and very low resistance in on-state. The mercury wetted reed switch has often been used for this purpose since it has good characteristics in all these respects. Few, if any, electronic components exhibit competitive advantages compared to the reed switch. The relative lack of parasitic effects means that it is close to being an ideal device. Based on earlier experiences by the authors, a new design has been developed with focus on electrical screening and coaxial design in order to realise a step generator that works into a high impedance instrument. Considerable work has been performed to characterise the new device with regard to steepness of step and most importantly, to voltage stability after the step. The most demanding part of this work has been to separate the performance of the switch from that of the oscilloscope. Findings indicate that the step rise-time is less than 0.5 ns, and settling to within 0.5 % within 10 ns.

  • 12.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Rietveld, Gert
    VSL, Netherlands.
    CIGRE Science & Enginering, Volume No.15, October 2019: Innovation in the Power Systems industry2019Inngår i: CIGRE Science & Engineering, ISSN 2426-1335, Vol. 15, s. 85-93Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Losses of HVDC converter stations need to be accurately quantified to support evaluation of bids for such systems and to underpin efforts to reduce greenhouse gas emissions. At present, these losses are estimated, based on loss calculations for individual converter components, and no reliable method exists to measure the actual HVDC converter station loss as difference between power on the AC- and DC-side of the station. The necessary requirements for such a measurement are investigated in this study, and a tentative design of a suitable loss measuring setup is explored. This approach is a useful alternative for those cases where a direct measurement of losses via a temporary connection with two converters operating in back-to-back mode cannot be made.

  • 13.
    Bergsten, Tobias
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Eklund, Gunnar
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Comparison between GaAs and graphene QHR standards for resistance realisation at SP2016Inngår i: Conference on Precision Electromagnetic Measurements (CPEM 2016), 2016, artikkel-id 7540514Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We report the first precision QHR measurements at SP using a graphene chip. We compare the results of a resistance calibration using GaAs based chips with the results using a graphene chip. The results agree within a few parts in 109 for calibrations of 100 Ω and 10 kΩ resistors. Consistency checks indicate that the uncertainty is lower with the graphene chip, and the noise level is slightly lower. The measurements with the graphene chip were performed exclusively at 4.2 K, which simplifies the calibration procedure considerably compared with GaAs chips.

  • 14.
    Bergsten, Tobias
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Eklund, Gunnar
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    He, Hans
    Chalmers University of Techology, Sweden.
    Comparing GaAs and graphene QHR standards for resistance realisation at SP2016Inngår i: Conference on Precision Electromagnetic Measurements 2016 (CPEM 2016), 2016Konferansepaper (Annet vitenskapelig)
  • 15.
    Bergsten, Tobias
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Rydler, Karl Erik
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Realization of Absolute Phase and AC Resistance of Current Shunts by Ratio Measurements2019Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 68, nr 6, s. 2041-2046Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a simplified method for realizing absolute phase and ac resistance for current shunts using only impedance ratio measurements. The method is based on three geometrically identical current shunts with different resistances, but with the same inductance, capacitance, and ac-dc resistance change of resistance at ac compared to dc). We demonstrate how the inductance, capacitance, and ac resistance can be calculated from the complex impedance ratio measurements, therefore realizing absolute current shunt impedance. The method gives competitive uncertainties of around 200 μΩ/Ω for amplitude and 400 μrad for phase at 1 MHz in the 1-Ω range.

  • 16.
    Bergsten, Tobias
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Rydler, Karl-Erik
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Realisation of Absolute Phase and Ac Resistance of Current Shunts by Ratio Measurements2018Inngår i: CPEM 2018 - Conference on Precision Electromagnetic Measurements, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This article presents a method for realising absolute phase and ac resistance for current shunts using only impedance ratio measurements. The method is based on three geometrically identical current shunts with different resistances, but with the same inductance, capacitance and ac resistance (change of resistance at ac compared to dc), We demonstrate how the inductance, capacitance and ac resistance can be calculated from the complex impedance ratio measurements, thereby realising absolute current shunt impedance. This method simplifies the procedure of current shunt calibration, since the same impedance ratio setup which is used to compare a shunt to a reference shunt, is used to realise the impedance of the starting reference shunt.

  • 17.
    Bergstrand, Sten
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Herbertsson, Magnus
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Rieck, Carsten
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Spetz, Jörgen
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Svantesson, Claes-Göran
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Haas, Rüdiger
    Chalmers University of Technology, Sweden.
    A gravitational telescope deformation model for geodetic VLBI2019Inngår i: Journal of Geodesy, ISSN 0949-7714, E-ISSN 1432-1394, Vol. 93, nr 5, s. 669-680Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have measured the geometric deformations of the Onsala 20 m VLBI telescope utilizing a combination of laser scanner, laser tracker, and electronic distance meters. The data put geometric constraints on the electromagnetic raypath variations inside the telescope. The results show that the propagated distance of the electromagnetic signal inside the telescope differs from the telescope’s focal length variation, and that the deformations alias as a vertical or tropospheric component. We find that for geodetic purposes, structural deformations of the telescope are more important than optic properties, and that for geodetic modelling the variations in raypath centroid rather than focal length should be used. All variations that have been identified as significant in previous studies can be quantified. We derived coefficients to model the gravitational deformation effect on the path length and provide uncertainty intervals for this model. The path length variation due to gravitational deformation of the Onsala 20 m telescope is in the range of 7–11 mm, comparing elevation 0$$^{\circ }$$∘and 90$$^{\circ }$$∘, and can be modelled with an uncertainty of 0.3 mm.

  • 18.
    Bergstrand, Sten
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Ralf, Schmid
    German Geodetic Research Institute, Germany.
    Activities of the IERS Working Group on Site Survey and Co-location2016Inngår i: International VLBI Service for Geodesy and Astrometry 2016 General Meeting Proceedings: "New Horizons with VGOS" / [ed] Dirk Behrend, Karen D. Baver, and Kyla L. Armstrong, Greenbelt, MD: National Aeronautics and Space Administration , 2016, s. 113-117Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The objective of the International Earth Rotation and Reference Systems Service (IERS) Working Group on Site Survey and Co-location is to improve local measurements at space geodesy sites. We appointed dedicated Points of Contact (POC) with the four different services of IERS as well as the NASA Space Geodesy Project in order to improve the efficiency of internal communication within the working group. Following the REFAG2014 conference, the POCs agreed on a common and general terminology on local ties that clarifies the communication regarding site surveying and co-location issues between and within the IERS services. We give brief introductions to the different observation techniques and mention some contemporary issues related to site surveying and co-location.

  • 19.
    Boork, Magdalena
    et al.
    RISE - Research Institutes of Sweden, Samhällsbyggnad.
    Wendin, Karin
    RISE - Research Institutes of Sweden, Biovetenskap och material, Jordbruk och livsmedel.
    Nordén, Johan
    RISE - Research Institutes of Sweden.
    Nilsson Tengelin, Maria
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Innemiljö i nytt ljus: Metoder för objektiv bedömning av belysning2017Rapport (Annet vitenskapelig)
    Abstract [sv]

    Nuvarande belysningsstandarder baseras enbart på tekniska krav, såsom ljusstyrka, jämnhet och luminans. Att även inkludera upplevelsebaserade krav skulle troligen främja bättre ljuskomfort, men även mer energieffektiva ljusmiljöer och produkter. Kunskapen om hur upplevda belysningsparametrar kan beskrivas är dock begränsad. Detta hämmar fastighetsägare och brukare att precisera önskvärda ljusmiljöer, liksom belysningstillverkare att utveckla produkter för nya marknader och tillämpningar. Syftet med detta forskningsprojekt var att utveckla och tillämpa sensoriska metoder på belysning. Till skillnad från tidigare metoder möjliggör sensoriska metoder objektiva bedömningar av upplevda belysningsparametrar.

    En analytisk panel bestående av åtta personer som uppfyller särskilda urvalskriterier rekryterades och tränades att bedöma belysningsprodukter i ett multisensoriskt laboratorium på SP Sveriges Tekniska Forskningsinstitut i Borås. Metodutvecklingen fokuserade särskilt på en effektiv träningsprocedur, hantering av ögats adaption, samt bedömning av färg och skuggningar. Förutom laboratorie-försök undersöktes möjligheten att genomföra analytiska bedömningar i en verklig kontext med samma försöksuppställning och panel.

    Resultaten visar att det är möjligt att använda sensorisk metodik för att genomföra objektiva belysningsbedömningar av armaturer; paneldeltagarna kunde skilja mellan attribut och prover. Signifikanta skillnader identifierades mellan de olika armaturerna, både i form av sensoriska och fysikaliska egenskaper såsom läsbarhet och bländning. Fysikaliska och sensoriska parametrar samvarierar dock inte alltid, vilket visar att fysikaliska och sensoriska mätningar ger kompletterande information om belysningskvalitet. Vidare visade bedömningsförsök i en verklig kontext att samma resultat uppnåddes som i laboratoriet, men med lägre signifikans, vilket verifierar metodens tillämpbarhet på belysning.

    Den genererade kunskapen väntas på sikt bidra till utveckling av verktyg som stödjer kommunikationen mellan olika professioner inom ljusdesign och planering och på så vis främja mer önskvärda och energieffektiva ljusmiljöer.

  • 20.
    Brolin, Magnus
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Aggregator trading and demand dispatch under price and load uncertainty2016Inngår i: IEEE PES Innovative Smart Grid Technologies Conference Europe, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The liberalization of electricity markets and the transformation of electric power systems to include large amounts of variable output generation, has led to a growing interest in flexible demand and demand response. Making demand response available on the wholesale market on a large scale is a challenge. Retailers and aggregators, providing services to individual consumers as well as bringing aggregated flexibility to the wholesale market, is foreseen to play important roles in this respect. This paper presents a aggregator decision support model for demand scheduling, including demand response and purchase bid optimization for day-ahead markets. Income from providing electricity to consumers, and costs related to imbalances, rescheduling and energy not served are also considered. The model includes risk management by applying the conditional value-at-risk risk measure. The feasibility of the developed model is validated through a case study using historical data from the Swedish power system and market.

  • 21.
    Cano, Stefan J
    et al.
    Modus Outcomes, UK.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Barbic, Skye P
    University of British Columbia, Canada.
    Fisher Jr, William P
    University of California, USA.
    Patient-centred outcome metrology for healthcare decision-making2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Valid and precise quantification of clinical variables is essential for appropriate interpretation to inform healthcare decision making. The outcomes produced from different measurement procedures and instruments, purporting to quantify the same measurand, should be directly comparable. This ensures the appropriate application and widespread adoption of clinical research findings. Metrology provides a framework for the development of a common language of reference measurement systems, which have the potential to improve the accuracy and comparability of patients’ results. However, the practices, procedures and instruments used in social measurement are currently excluded from any formal metrological framework. In this paper, we build on previous arguments, and propose a new international body to bring together metrology, psychometrics, philosophy, and clinical management to support the global comparability and equivalence of measurement results in patient centred outcome measurement to improve healthcare.

  • 22.
    Cano, Stefan
    et al.
    Modus Outcomes, UK.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Melin, Jeanette
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Fisher, William
    University of California, US.
    Towards consensus measurement standards for patient-centered outcomes2019Inngår i: Measurement, Vol. 141, s. 62-69Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Patient centered outcomes pertain to a patient's beliefs, opinions and needs in conjunction with a clinician's medical expertise and assessment. The rise of patient-centered outcome (PCO) measurement parallels increased interest in patient-centered care. PCO measures offer the opportunity for more meaningful measurement of health outcomes informative enough to guide treatment decisions. However, it has been suggested that, for practical and scientific reasons, existing PCO measures are currently not capable of delivering the kind of quality assured measurement required for high-stakes decision making. Potential solutions include: addressing the lack of units in PCO measurement through recourse to mathematical models devised to define meaningful, invariant, and additive units of measurement with known uncertainties; establishing coordinated international networks of key stakeholders guided by five principles (i.e., collaboration, alignment, integration, innovation and communication); better use of technology leveraging measurement through item banks linking PCO reports via common items, common patients, or specification equations based in strong explanatory theory. And finally ensuring PCO measurement always is associated with: (1) a clear definition of the measurand in regards to the intended clinical use; (2) a clear definition of the clinically allowable error of measurement; (3) international cooperation and consensus to navigate the complexities of the development of metrologically sound reference measurement systems; and (4) continued clinical validation of newly calibrated measures. In this article, we illustrate the principles to improve PCO measures with examples from breast cancer, vision-related patient-reported outcome measures, and dementia clinician-reported and performance outcome measures.

  • 23.
    De Huu, Marc A.
    et al.
    METAS Federal Institute of Metrology, Switzerland.
    Büker, Oliver
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Christensen, R.
    FORCE Technology, Denmark.
    Macdonald, Marc
    NEL, UK.
    Maury, René C.
    CESAME-EXADEBIT SA, France.
    Schrade, M.
    Justervesenet, Norway.
    Petter, Harm Tido
    VSL, The Netherlands.
    Stadelmann, P.
    Empa, Switzerland.
    The European Research Project on Metrology for Hydrogen Vehicles - MetroHyVe2018Inngår i: Journal of Physics: Conference Series, Institute of Physics Publishing , 2018, Vol. 1065, nr 9, artikkel-id 092017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A large hydrogen infrastructure is currently in development across Europe. However, the industry faces the dilemma that they are required to meet certain measurement requirements set by European legislation that cannot currently be followed due to the lack of available methods and standards. The EMPIR Metrology for Hydrogen Vehicles project will be the first large scale project of its kind that will tackle the four measurement challenges that currently prevent the industry from meeting requirements set by International Standards such as flow metering, quality control, quality assurance and sampling. This paper presents a brief overview of the specific objectives of the project and focuses on the flow metering work package and the presentation of its planned tasks, which comprise laboratory and measurements in the field. Laboratory work will assess the use of substitute fluids to hydrogen to provide a safer and more cost effective method for the type approval of Hydrogen Refuelling Stations (HRS). To be able to link laboratory work to field testing, mobile primary standards will be developed and the design of a field testing primary standard will be addressed. The aim is to inform what the European national metrology institutes are currently developing in the field of hydrogen flow metering and quality control of HRS.

  • 24.
    Draxler, K.
    et al.
    CTU, Czech Republic.
    Styblikova, R.
    CMI, Czech Republic.
    Hlavacek, J.
    CTU, Czech Republic.
    Rietveld, G.
    VSL, Netherlands.
    Van Den Brom, H. E.
    VSL, Netherlands.
    Schnaitt, M.
    BEV, Austria.
    Waldmann, W.
    BEV, Austria.
    Dimitrov, E.
    BIM, Bulgaria.
    Cincar-Vujovic, T.
    DMDM, Serbia.
    Paczek, B.
    GUM, Poland.
    Sadkowski, G.
    GUM, Poland.
    Crotti, G.
    INRIM, Italy.
    Martin, R.
    LCOE, Spain.
    Garnacho, F.
    LCOE, Spain.
    Blanc, I.
    LNE, France.
    Kampfer, R.
    METAS, Switzerland.
    Mester, C.
    METAS, Switzerland.
    Wheaton, A.
    NPL, UK.
    Mohns, E.
    PTB, Germany.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Hammarquist, Maria
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Cayci, H.
    UME, Turkey.
    Hallstrom, J.
    VTT, Finland.
    Suomalainen, E. -P
    VTT, Finland.
    Results of an International Comparison of Instrument Current Transformers up to 10 kA at 50 Hz Frequency2018Inngår i: CPEM 2018 - Conference on Precision Electromagnetic Measurements, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Traceability of the current ratio is crucial for the measurement of electrical energy in revenue metering. A comparison of the AC current ratio was therefore performed within EURAMET in the time period 2012-2016, using a precision CT as the traveling device. The Czech Metrology Institute (CMI) as coordinator processed the measurement results of the 15 European participating laboratories. The comparison of the results for transformer ratios of (4, 5, 6, 8, 10) kA 5 A at 15 VA burden and (4 and 10) kA 5 A ratios at 5 VA burden indicates good agreement between the participating laboratories. The main differences are found for phase displacement, at least in part due to instability of the traveling standard. .

  • 25.
    Ebenhag, Sven Christian
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Hedekvist, Per Olof
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Jarlemark, Per
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Sundblad, Ragnar
    Netnod Internet Exchange, Sweden.
    Redundant Distributed Timescale Traceable to UTC(SP)2019Inngår i: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A variety of commerce needs or requires accurate time, such as air traffic control, bank transactions and computer log file comparisons. Whenever the used time needs to be compared with a timestamp generated by another system, both systems must be traceable to a common reference, such as a local UTC(k) realization. Within this paper a distributed timescale using five nodes across Sweden is presented. The foundation for time keeping at each node is two cesium clocks, which are connected to time analysis equipment and equipment for producing redundant timescales. Both timescales are used and distributed throughout the time node and then prioritized by the local NTP servers, PTP grand masters, and other time distribution services. The timescales are monitored by RISE Research Institute of Sweden to ensure traceability to UTC(SP).To compare the timescales of each location with the other locations, GNSS common view is primarily used with an alternative fiber-based solution as back-up. All available time signals are measured relative to the master timescale, and that data is distributed to the other locations to be used as input in the steering of the local timescales. The NTP servers of the time nodes are directly connected to Internet Exchange points, for central, highly available and fair connectivity to the Internet. 

  • 26.
    Ebenhag, Sven Christian
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Hedekvist, Per Olof
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Rieck, Carsten
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Bergroth, Magnus
    SUNET, Sweden.
    Krehlik, Przemyslaw
    AGH University of Science and Technology, Poland.
    Sliwczynski, Lukasz
    AGH University of Science and Technology, Poland.
    Evaluation of Fiber Optic Time and Frequency Distribution System in a Coherent Communication Network2019Inngår i: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A fiber-based time transfer between UTC(SP) and the VLBI-station at Onsala Space Observatory has been evaluated. The transfer uses a single wavelength in an active coherent DWDM-network in unidirectional duplex fibers and is routed through Reconfigurable Optical Add-Drop Multiplexers.

  • 27.
    Ebenhag, Sven-Christian
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Hedekvist, Per Olof
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Liström, Stefan
    SUNET Swedish University Computer Network, Sweden.
    Bergroth, Magnus
    NORDUnet, Sweden.
    Time and Frequency Dissemination in an All-optical Coherent Fiber Communication Network2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A nationwide fiber optic communication network utilizing state-of-the-art technologies with data modulation both in the polarization and in multi-level amplitude and phase is being deployed in Sweden. The network is operated by the Swedish University computer Network, and connects all universities and several research facilities in the country through redundant connections. Since there is a limited amount of clients connected to the network, each client will be assigned a personal wavelength. With a network that is all-optical through an advanced utilization of dynamically reconfigurable optical add and drop multiplexers, each wavelength can theoretically be connected to any other client within the network, enabling broadcasting on allocated wavelengths. The coherent modulation formats also enables signal recovery through electronic digital signal processing after detection, and no optical dispersion compensation is thereby installed. This new network scheme enables a brand new implementation of frequency and time dissemination in the network. The omission of dispersion compensation fibers enhances the symmetry in duplex fiber pair transmission. These optical add-drop installations allow for future efficient frequency and time signal broadcasting from reference nodes operated by distributors such as SP Technical Research Institute of Sweden to users connected to the network.

  • 28.
    Ebenhag, Sven-Christian
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Hedekvist, Per Olof
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Weddig, Ludvig
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Measurement and Analysis of Polarization Variations in an Optical Coherent Fiber Communication Network Utilized for Time and Frequency Distribution2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    When fiber optic communication networks are used for ultra-stable timing or frequency transfer, there will always be an influence of polarization variation to some extent. The variations can be induced by e.g. mechanical vibration or electromagnetic effects from adjacent power lines. The output polarization from a 120 km fiber transmission of an ultra-stable optical frequency is analyzed and the requirements of a compensation device are quantified.

  • 29.
    Ehnberg, Jimmy
    et al.
    Chalmers University of Technology, Sweden.
    Lennerhag, Oscar
    Independent Insulation Group, Sweden.
    Hillberg, Emil
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Perez, A.
    ABB, Sweden.
    Mutule, Anna
    Institute of Physical Energetics, Latvia.
    Zikmanis, I.
    Institute of Physical Energetics, Latvia.
    Categorisation of Ancillary Services for Providers2019Inngår i: Latvian Journal of Physics and Technical Sciences, ISSN 0868-8257, Vol. 56, nr 1, s. 3-20Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The focus of the work presented here is to raise awareness of how ancillary services within the NordPool area could be of value in supporting the future grid, and who could be the provider of these services. The ancillary services considered here are not limited to the current market, but also services for future market solutions as well as services for fulfilment of grid codes. The goal is to promote the development of existing and novel solutions to increase the utilisation and thus the value of equipment within the power system. The paper includes a techno-economical categorisation of ancillary services, from a provider's perspective, presenting opportunities and competition. Furthermore, procurers of services could utilise this kind of categorisation to identify possible providers or partners. The analysis of the categorisation shows a broad range of possible providers for each service and a broad range of possible services from each provider.

  • 30.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Qualifying a Transient Recorder for Traceable Measurements of Very Fast Transients2018Inngår i: CPEM 2018 - Conference on Precision Electromagnetic Measurements, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the qualification of a transient recorder used in a system for traceable measurements of Very Fast Transients. The system is designed for traceable measurements of VFT up to 100 kV, having a target settling time < 10 ns, a peak voltage error < 1\%, and a front time error < 5\%. The rise time of the digitizer is 1.6 ns at 50Ω and 1.2 ns at 1 MΩ. Step responses show settling times of 4.5 ns. A convolution method gives a peak voltage error of 0.12% and a front time error of 4.1% for 4.5ns front times. © 2018 IEEE.

  • 31.
    Flys, Olena
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik. Halmstad University, Sweden.
    Jarlemark, Per
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Petronis, Sarunas
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Stenlund, Patrik
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Rosen, B. -G
    Halmstad University, Sweden.
    Applicability of characterization techniques on fine scale surfaces2018Inngår i: Surface Topography: Metrology and Properties, ISSN 2051-672X, Vol. 6, nr 3, artikkel-id 034015Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, several surface topographies typical for dental implants were evaluated by different measurement techniques. The samples were prepared by machine turning, wet chemical etching and electrochemical polishing of titanium discs. The measurement techniques included an atomic force microscope (AFM), coherence scanning interferometer (CSI) and a 3D stereo scanning electron microscope (SEM). The aim was to demonstrate and discuss similarities and differences in the results provided by these techniques when analyzing submicron surface topographies. The estimated surface roughness parameters were not directly comparable since the techniques had different surface spatial wavelength band limits. However, the comparison was made possible by applying a 2D power spectral density (PSD) function. Furthermore, to simplify the comparison, all measurements were characterized using the ISO 25178 standard parameters. Additionally, a Fourier transform was applied to calculate the instrument transfer function in order to investigate the behavior of CSI at different wavelength ranges. The study showed that 3D stereo SEM results agreed well with AFM measurements for the studied surfaces. Analyzed surface parameter values were in general higher when measured by CSI in comparison to both AFM and 3D stereo SEM results. In addition, the PSD analysis showed a higher power spectrum density in the lower frequency range 10-2-10-1 μm-1 for the CSI compared with the other techniques.

  • 32.
    Gidlund, Henrik
    et al.
    Trafikverket, Sweden.
    Lindgren, Mikael
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Muzet, Valerie
    CEREMA, France.
    Rossi, Giuseppe
    INRIM Istituto Nazionale di Ricerca Metrologica, Italy.
    Iacomussi, Paola
    INRIM Istituto Nazionale di Ricerca Metrologica, Italy.
    Road surface photometric characterisation and its impact on energy savings2019Inngår i: Coatings, ISSN 2079-6412, Vol. 9, nr 5, artikkel-id 286Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    How road surfaces reflect light in space is a physical characteristic that plays a key role in the design of road lighting installations: by European Standards the average luminance is the target quantity to assure the required safety conditions of the motorized road traffic. Lighting systems are designed (luminous flux installed per kilometre) to comply with the above requirement, starting from reference values of road surfaces reflection published in an old scientific document. These data are obsolete and not representative of current road surfaces, but they are still used to design current LED lighting systems. European Community funded a SURFACE project to provide to EU standard organization new traceable reference data, representative of current road surfaces used in EU. The paper presents the data collections and the impact on road lighting of using available old reference data versus SURFACE collected data of current road surfaces. Results highlight advantages in using bright pavements as well the need for introducing systems for flux control in road lighting installation to compensate for the discrepancies between current reference data and actual road surface data.

  • 33.
    Havunen, Jussi
    et al.
    VTT-MIKES, Finland.
    Hällström, Jari
    VTT-MIKES, Finland.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Bergman, Allan E.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Using deconvolution for correction of non-ideal step response of lightning impulsedigitizers and measurement systems2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Lightning impulse measurements can be highly influenced by measurement arrangement, characteristics of high voltage divider, digitizer (transient recorder) performance, and algorithms used for parameter evaluation. The main sources of measurement errors are the non-ideal step responses of digitizer and voltage divider. This paper discusses the use of deconvolution to correct for the non-ideal step response of a digitizer, and of a large mixed divider. Correcting the step response of the complete measuring system by one part at a time is desirable because it allows to evaluate the effectiveness of the correction with trustworthy methods. Step response describes the output of a system as function of time when its input changes between two levels infinitely fast. Real life impulse digitizers and impulse voltage dividers have a finite rise time, and the response does not immediately settle to final value. Slow rise time is often the cause of error for front time parameter. Creeping response is often the cause of error for time to half-value parameter. Step response of an instrument can be determined by applying a stable, known direct voltage, which is then shorted to ground by a mercury-wetted relay. The mercury-wetted relay is assumed nearly an ideal switch, which creates almost an ideal voltage step for input of the instrument. Convolving the derivative of the measured step response with an ideal input gives a measure of distortion caused by the non-perfect step response, and conversely deconvolving the measured step response with the measured signal gives the original input signal. This paper presents an FFT-based method for step response correction using deconvolution. Deconvolution is a mathematical process, which is used to reverse the non-ideal effects of measuring instrument on recorded data. Effectiveness of the method is demonstrated by two examples. In the first example, the non-ideal step responses of the different ranges of an impulse digitizer are corrected. Functionality of the step response correction is evaluated by comparing the results against a calculable impulse voltage calibrator. Results showed that the step response correction reduced errors in lightning impulse parameters. Stability of the step response correction was analysed by studying several impulse calibration results that have been performed for the instrument within a year. The second example corrects the response of a 2400 kV impulse voltage divider. The effectiveness of the correction is evaluated by comparing its results to a 400 kV reference divider.

  • 34.
    Havunen, Jussi
    et al.
    VTT, Finland.
    Passon, Stephan
    PTB, Germany.
    Hallstrom, Jari
    VTT, Finland.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Effect of Coaxial Cables on Measurements Performed with Resistive Lightning Impulse Voltage Dividers2018Inngår i: CPEM 2018 - Conference on Precision Electromagnetic Measurements, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The effect of the coaxial cable type and length on the lightning impulse parameters is often neglected. However, studies have shown that the coaxial cable length can affect the parameters that are calculated according to IEC 60060-1:2010. This study investigates how different coaxial cables influence the impulse waveforms by measuring the input and output of the cable under test with a 2-channel digitizer. Non-standard lightning impulses were generated using an impulse voltage calibrator. Results indicate that coaxial cables attenuate the test voltage and increase both the front time and time-to-half value.

  • 35.
    He, Hans
    et al.
    Chalmers University of Technology, Sweden.
    Lara-Avila, Samuel
    Chalmers University of Technology, Sweden.
    Bergsten, Tobias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Eklund, Gunnar
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Kim, Kyung
    Chalmers University of Technology, Sweden.
    Yakimova, Rositza
    Linköping University, Sweden.
    Park, Yung Woo
    Seoul National University, South Korea.
    Kubatkin, Sergey
    Chalmers University of Technology, Sweden.
    Stable and Tunable Charge Carrier Control of Graphene for Quantum Resistance Metrology2018Inngår i: 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018), 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Here we demonstrate a stable and tunable method to alter the carrier concentration of epitaxial graphene grown on silicon carbide. This technique relies on chemical doping by an acceptor molecule. Through careful tuning one can produce chemically doped graphene quantum resistance devices which show long-term stability in ambient conditions and have performance comparable to that of GaAs quantum resistance standards. This development paves the way for controlled device fabrication of graphene quantum hall resistance standards, which can be reliably tailored to operate below 5 T and above 4 K out-of-the-box, without further adjustments from the end-user.

  • 36.
    He, Hans
    et al.
    Chalmers University of Technology, Sweden.
    Lara-Avila, Samuel
    Chalmers University of Technology, Sweden; National Physical Laboratory, UK.
    Kim, Kyung
    Chalmers University of Technology, Sweden.
    Fletcher, Nick
    National Physical Laboratory, UK.
    Rozhko, Sergiy
    National Physical Laboratory, UK.
    Bergsten, Tobias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Eklund, Gunnar
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Cedergren, Karin
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Yakimova, Rositsa
    Linköping University, Sweden.
    Park, Yung
    Seoul National University, South Korea; University of Pennsylvania, US.
    Tzalenchuk, Alexander
    National Physical Laboratory, UK.
    Kubatkin, Sergey
    Chalmers University of Technology, Sweden; University of London, UK.
    Polymer-encapsulated molecular doped epigraphene for quantum resistance metrology2019Inngår i: Metrologia, ISSN 0026-1394, E-ISSN 1681-7575, Vol. 56, nr 4, artikkel-id 045004Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the aspirations of quantum metrology is to deliver primary standards directly to end-users thereby significantly shortening the traceability chains and enabling more accurate products. Epitaxial graphene grown on silicon carbide (epigraphene) is known to be a viable candidate for a primary realisation of a quantum Hall resistance standard, surpassing conventional semiconductor two-dimensional electron gases, such as those based on GaAs, in terms of performance at higher temperatures and lower magnetic fields. The bottleneck in the realisation of a turn-key quantum resistance standard requiring minimum user intervention has so far been the need to fine-tune the carrier density in this material to fit the constraints imposed by a simple cryo-magnetic system. Previously demonstrated methods, such as via photo-chemistry or corona discharge, require application prior to every cool-down as well as specialist knowledge and equipment. To this end we perform metrological evaluation of epigraphene with carrier density tuned by a recently reported permanent molecular doping technique. Measurements at two National Metrology Institutes confirm accurate resistance quantisation below 5n-1. Furthermore, samples show no significant drift in carrier concentration and performance on multiple thermal cycles over three years. This development paves the way for dissemination of primary resistance standards based on epigraphene

  • 37.
    Hedekvist, Per Olof
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Weddig, Ludwig
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Ebenhag, Sven C
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Analysis and compensation of polarization in an optical frequency transfer through a fiber communication network2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the fiber optic link, connecting RISE research facilities in Borås with the Photonics Lab at Chalmers University of Technology in Gothenburg, the signal is substantially distorted by polarization variations. It has been verified that the variations are induced by the electrical power grid, however unknown at which segment of the link that it occurs. While this distortion is effectively handled by standard equipment for the data transmission, it deteriorates the detection of a transmitted ultra-stable frequency, using heterodyne mixing. Thus, the magnitude and severity of this distortion is quantified, and some compensation techniques are evaluated.

  • 38.
    Hillberg, Emil
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    A proposed framework for coordinated power system stability control: reference 7422018Rapport (Annet vitenskapelig)
    Abstract [en]

    Power system security is defined as the ability of the power system to withstand the occurrence of

    credible disturbances as defined by security criteria or standards. Stability control, which is one of the

    pillars to system security and the subject of this technical brochure, aims at maintaining the security

    of supply according to cost-effective criteria. It has always been a top priority in both industrial

    practice and academic research to ensure the reliable operation of power systems. To this end,

    extensive activities have already been undertaken by e.g. CIGRE in the field of power system stability

    control and Dynamic Security Assessment (DSA).

    Analysis from past blackouts and major system disturbances has pointed out some potential

    deficiencies in current stability control techniques. These deficiencies are related to various aspects of

    design and maintenance of control systems, being a direct result of the insufficient systematic design

    and adaptability of, and coordination among, the conventional stability controls. According to a

    questionnaire survey conducted by this JWG, the full benefits from a systematic framework approach

    for power system stability were recognized by many of the respondents. All these key elements are

    integrated in the framework proposed by this JWG and reflect the existing experience.

    This TB proposes a framework consisting of the four established control types described below and

    coordinating them to achieve enhanced performance. As fundamental requirement to achieve this

    goal, the proposed framework associates these stability control types with their respective system

    states. The first control type is named preventive control. It is activated in the normal or alert state,

    and is carried out to maintain a sufficient stability margin. Once a predefined contingency occurs the

    system could rapidly evolve towards an emergency state, where the second stability control type,

    called event-based control, is triggered. The third stability control type, called response-based control,

    is usually initiated following the violation of key variable limits in the emergency state. In cases where

    the operation of all the previous controls proves insufficient, the system will degrade to a blackout

    state. Restorative control, the fourth control type, is activated following a blackout or after an

    emergency state and remains active over the whole restoration process.

    This TB emphasises that these control types gain added value if they are adaptive and coordinated as

    recommended in the proposed framework. When adaptive, they are able to adjust their control

    decision set to the current operating condition and identify the contingencies. The coordination of

    these adaptive controls yields a more cost-effective set of planned control decisions

    This TB describes the functional structure of the proposed framework whose design shares the same

    architecture of an online DSA system as well as the same configuration and hardware of existing

    automatic control devices at substations.

    This functional structure is comprised of four high-levels modules:

    Wide area data acquisition and information processing,

    Real-time monitoring, online estimation and online stability analysis,

    Adaptive and coordinated decision planning of stability control, and

    Automatic activation of event-based and response-based controls.

    The first and second high-level modules are already well established in the industry. However, the

    third module is not yet at the same maturity level. To this end, this TB recommends the following

    elements in order to design and develop software with required functionalities in the proposed

    framework: Quantitative stability analysis, Determining in advance the optimal stability control decision for each relevant control type,

    and

    Coordinating the previously determined stability control decisions across all control types.

    This framework and its underlying software strongly rely on its integration with online DSA and other

    tools used at the control centre. Besides, these systems are fed with field data from measurement

    devices (e.g. PMUs) whose number and location should be effectively selected. Data exchange

    protocols between all these elements are critical for their integration into the framework. Bad data

    detection is a prerequisite for online monitoring and analysis, and absolutely critical for the smooth

    functioning of the framework so that proper stability control decisions are always taken.

    This TB also provides some key considerations and recommendations in the design and

    implementation of the proposed framework for 1) specification designers, 2) manufacturers and 3)

    system operators.

    Before implementing such a framework, the grid owner (and also the specification designer) should

    conduct a cost benefit analysis to compare its effectiveness with alternatives.

    After the grid owner decides to implement such framework, demonstration projects and trial

    operations have to be conducted with a particular focus on validation of

    control decision planning. It is

    highly recommended to develop laboratory or field validation tests for key devices and systems. These

    tests need to be conducted before as well as after commissioning. Especially for event-based and

    response-based controls, which operate infrequently, post-commissioning testing remains important.

    It has to be mentioned that there are still some remaining issues. One of these is the execution of the

    optimisation process that is quite complex and consists of an iterative search based on simulations.

    Currently this optimisation does not guarantee a global optimum or even convergence. This issue

    should be the focus of research and development by both manufacturers and academia. Another

    major issue to be tackled by specification designers relates to cyber security aspects, which have only

    been briefly touched upon in this TB. Thirdly, the remote modification of control settings is not yet a

    widely accepted practice, and the proper design of operator’s intervention and validation mechanisms

    is still lacking. To address these issues more effort is needed mainly from the system operator’s perspectives.

    The proposed framework is expected to overcome most of the deficiencies of the current stability

    controls. Yet, some challenges do remain and the following suggestions for future work are provided.

    Firstly, the applicability of the proposed framework in a multi-TSO environment with common grid

    model, mainly in the emergency state, needs further investigation. Secondly, power oscillations that

    occasionally occur and might cause the triggering of incorrect control decisions, should be fully

    understood and have their adverse consequences mitigated. Further development would be directed

    towards the improvement of control decision planning by combining system-wide response

    measurements with pre-disturbance simulation results. Thirdly, the stability characteristics of modern

    power systems are changing due to the increasing level of power electronics devices. Its impact on

    stability control needs to be properly determined in order to ensure the correct operation of the proposed framework.

  • 39.
    Hillberg, Emil
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Development of improved aggregated load models for power system network planning in the Nordic power system Part 2: Method verification2018Rapport (Annet vitenskapelig)
    Abstract [en]

    In this paper, we describe the results from an ongoing project to update the modelling strategies of load models used for planning purposes by the Nordic Transmission System Operators (TSOs) Svenska kraftnät, Fingrid & Statnett. The background to this project and a description of the development of this methodology was published as Part 1 of this set of papers, presented at the Cigré 2016 Session [1]. During 2016, the methodology has been through a verification phase which is partly presented in [2] and [3] with further details presented in this paper.

    The load response to voltage and frequency changes may have a significant impact on the dynamic behaviour of the power system. In this sense, the selection of load model structures and load model parameterisation gain an increased interest as power systems are operated closer to their limits. Modelling of loads is however highly complex due to the vast number of load devices in a power system, making it unfeasible to model each device separately as well as making it unfeasible to model each possible loading scenario. Based on this, a methodology for development of load models has been presented in [1]. In the work with validating this methodology, several challenges as well as strengths of the method have been identified. For the voltage dependency of the active power part of the load, the validation successfully provided evidence of the validity of the method. For reactive power, only a partial validation could be performed due to limited level of reactive power in gathered measurements. The load model structure used in this project is identified as a limiting factor for the representation of the non-linear behaviour of this part of the load. Frequency dependency of load has only been addressed to a limited extent, with results illustrating the difficulties to assess this kind of behaviour from measurements gathered during this project.

    All in all, from the results of the validation it is found that the method is suitable to be employed on a larger scale with some differences in approach regarding the assessment of the voltage and frequency behaviour of the load. Furthermore, this work has provided valuable input for the understanding of the behaviour of the load.

  • 40.
    Hillberg, Emil
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Une proposition d'architecture ducontrôle de la stabilité des réseauxélectriques: 7422018Rapport (Annet vitenskapelig)
  • 41.
    Hiller, Carolina
    et al.
    RISE - Research Institutes of Sweden, Samhällsbyggnad.
    Wendin, Karin
    RISE - Research Institutes of Sweden, Biovetenskap och material, Jordbruk och livsmedel.
    Nilsson Tengelin, Maria
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Utveckling och tillämpning av sensoriska metoder för objektiva belysnings-bedömningar, del I2017Rapport (Annet vitenskapelig)
    Abstract [sv]

    I dag finns tekniska belysningsstandarder som inkluderar parameterar så som ljusstyrka, jämnhet och luminans. Det som saknas är krav som grundar sig på människors upplevelser av belysning och ljusmiljöer. Att få med den upplevelsebaserade dimensionen skulle betyda ett helhetstänk som förmodligen skulle gynna både ljuskomforten och än mer energieffektiva ljusmiljöer och produkter. Att beskriva upplevda belysningsparametrar har hittills visat sig inte vara helt enkelt, och här saknas både kunskap och en gemensam begreppsvärld inom branschen; något som hämmar fastighetsägare att ställa lämpliga krav vid en upphandling liksom belysningstillverkare att utveckla produkter för nya marknader och tillämpningar. Det övergripande syftet med detta forskningsprojekt är att utveckla och tillämpa sensoriska metoder på belysning. Till skillnad från tidigare metoder möjliggör sensoriska metoder objektiva bedömningar av upplevda belysningsparametrar. Syftet med försöken som redovisas i denna delrapport är att vidareutveckla och testa metoden ytterligare. Detta görs genom att nya armaturer testas liksom att försök utförs i en ny verklig kontext (kontorsmiljö). Försöken bygger vidare på resultat från tidigare försök som har rapporterats om i (Boork et al, 2017).

    En analytisk panel bestående av åtta personer, som uppfyllde särskilda urvalskriterier, har tidigare rekryterats och dessa personer tränades nu för detta specifika delprojekt för att bedöma belysningsprodukter i ett multisensoriskt laboratorium på RISE Research Institutes of Sweden i Borås. Metodutvecklingen fokuserade särskilt på en effektiv träningsprocedur, hantering av ögats adaption, samt bedömning av färg och skuggningar. Förutom laboratorieförsök undersöktes möjligheten att genomföra analytiska bedömningar i en verklig kontext med samma försöksuppställning och panel.

    Resultaten visade att det är möjligt att använda sensorisk metodik för att genomföra objektiva belysningsbedömningar även för de testade belysningsprodukterna, dvs mindre LED-spotlights. Signifikanta skillnader identifierades mellan de olika armaturerna och som i tidigare försök spelade färgtemperaturen en stor roll för flera av de bedömda egenskaperna; inte minst förstås för ljuskällans gulhet och för läsbarhet (textkontrasten). Liksom i tidigare försök fanns det samband mellan de fysikaliska mätningarna och sensoriska bedömningarna, men inte för alla egenskaper, vilket visar att fysikaliska och sensoriska mätningar ger kompletterande information om belysning.  Vidare visade bedömningsförsök i en verklig kontext att likvärdiga resultat uppnåddes som i laboratoriet, om ändock något spretigare och inte heller lika entydiga i jämförelse med verklig kontext i tidigare försök.

    Den genererade kunskapen väntas på sikt bidra till utveckling av verktyg som stödjer kommunikationen mellan olika professioner inom ljusdesign och planering och på så vis främja mer önskvärda och energieffektiva ljusmiljöer.

  • 42.
    Hällström, J
    et al.
    Helsinki University of Technology (TKK), Finland.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Ding,
    Beijing Hua Tian Mechanical-Electrical Institute (BHT), China.
    Garnacho, F
    Electrotechnical Official Central Laboratory (LCOE), Spain.
    Gobbo, R
    University of Padova, Italy.
    Kato, T
    Doshisha University, Japan.
    Li, Y
    National Measurement Institute (NMIA), Australia.
    Nilsson, Andreas
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Pesavento, G
    University of Padova, Italy.
    Sato, S
    Utsunomiya University, Japan.
    Yu, AX
    Beijing Hua Tian Mechanical-Electrical Institute, China.
    International comparison of software for calculation of lightning impulse parameters based on a new processing algorithm2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A new algorithm has been proposed to calculate the parameters of full lightning voltage impulses. The new algorithm enables the application of the test voltage factor (also referred to as k-factor in some literatures) for calculation of the equivalent test voltage of impulses with superimposed oscillations/overshoots. The new algorithm at the same time provides a robust procedure for obtaining time parameters of the impulses from not only smooth waveforms but also waveforms with varying degrees of distortions in the front part of the impulses. These distortions include oscillations on the impulse front and overshoots in the peak region. A critical part of the new algorithm is a 4-parameter fitting procedure to obtain the base curve, which is used for calculation of the test voltage curve. Another important part of the algorithm is applying a filtering procedure in the calculation of the test voltage curve.

     

    The new algorithm was tested in different laboratories using different programming languages and different techniques for realising the fitting and filtering routines. The paper reports the results obtained from the participating laboratories using the proposed algorithm. The results obtained by the participating laboratories using existing software based on the requirement of IEC 60060-1: 1989 were also compared. It is anticipated that the results can serve as a part of the basis for a new procedure for determination of lightning impulse parameters in the revised IEC 60060-1.

  • 43.
    Iacomussi, P
    et al.
    INRIM, Italy.
    Rossi, G
    INRIM, Italy.
    Blatter, P
    METAS, Switzerland.
    Reber, J
    METAS, Switzerland.
    Chain, C
    Cerema, France.
    Muzet, V
    Cerema, France.
    Dubard, J
    LNE, France.
    Van Tang, C
    LNE, France.
    Jouanin, A
    OPTIS, France.
    Kubarsepp, T
    Metrosert, Estonia.
    Lindgren, Mikael
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Manocheri, F
    Aalto University, Finland.
    Zehntner, P
    Zehntner GmbH, Switzerland.
    Metrology of Road Surface for Smart Lighting2017Inngår i: PROCEEDINGSOF THE LUX EUROPA 2017 European Lighting Conference: Lighting for modern society / [ed] Matej B. Kobav, University of Ljubljana, Slovenia, Ljubljana, 2017, s. 103-107, artikkel-id OM17Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The knowledge of the luminance coefficient q or of the reduced luminance coefficient r of road surface is an unavoidable requirement for designing road lighting installations able to assure adequate road luminance for visual conditions, energy consumption and traffic safety according to standard requirements. Unfortunately q available data refers to measurements made during the seventies with no traceability or measurement uncertainty. In the last 40 years the road surfaces pavements evolved as well the road lighting sources and luminaires. EMPIR project SURFACE will provide validated, optimised and reliable geometrical conditions for the measurement of q as well as reference data representative of current road pavements and future needs, as support of the European Standardisation process, CIE and European Metrology infrastructure.

  • 44.
    Jaldehag, Kenneth
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Jarlemark, Per
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Rieck, Carsten
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Further Evaluation of CGGTTS Time Transfer Software2019Inngår i: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A new software tool for GNSS time transfer implementing the Common GNSS Generic Time Transfer Standard (CGGTTS) was developed by the time and frequency group at RISE Research Institutes of Sweden. The software is called RISEGNSS and converts RINEX observational data into CGGTTS data. It handles codes and carriers of the satellite navigation systems GPS, GLONASS, Galileo and BeiDou including the most important ranging codes for time transfer applications. The software is also prepared for single-frequency applications, and for the use of non-standard codes and carriers such as Galileo PRS and those from SBAS. The aim of the development is to provide an alternative to existing software and to support time transfer with new GNSS. This paper presents a full comparison of new versions of RISEGNSS and the well-established software R2CGGTTS, developed by the Royal Observatory of Belgium. The evaluation includes the linear combinations recommended in the CGGTTS standard for time transfer applications using GPS, GLONASS, Galileo and BeiDou. The aim of the evaluation is to support the development in making CGGTTS data compatible between different stand-alone software as well as those implemented in receivers, which is important to make Common-View (CV) time transfer results precise and accurate. The paper also presents CV time transfer results for three different baselines based on CGGTTS data obtained from the RISEGNSS software. The results include those obtained from dual-frequency code combinations of the four GNSS: GPS, Galileo, GLONASS and BeiDou. The results also include those of using standard single-frequency code observables as well as nonstandard codes and carriers such as L5 for GPS, E5b and E5 (Alt-BOC) for Galileo, G3 for GLONASS, and B3 for BeiDou. It finally studies the possibility and quality of using SBAS for time transfer. 

  • 45.
    Jaldehag, Kenneth
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Rieck, Carsten
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Jarlemark, Per
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Evaluation of CGGTTS time transfer software using multiple GNSS constellations2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A new software tool for GNSS time transfer implementing the Common GNSS Generic Time Transfer Standard (CGGTTS) has been developed by the time and frequency group at RISE Research Institutes of Sweden. The software handles signals from the satellite navigation systems GPS, GLONASS, Galileo and BeiDou including the most important ranging codes for time transfer applications. The aim of the development is to provide an alternative to existing software and to support time transfer with new GNSS. The paper presents an evaluation of CGGTTS data calculated with the new software tool in comparison with those calculated using two other, independently developed software tools. It is shown that the results obtained from the different software agree to the sub-nanosecond level. Specifically, the agreement seen between individual GPS, Galileo and BeiDou CGGTTS data is at the 100- to 200-picosecond level. Similarly, GLONASS CGGTTS data agree to the sub-nanosecond level. Further, the paper presents a comparison between time transfer links for both long baselines and short, common-clock baselines obtained from a common view analysis of CGGTTS data from the four mentioned GNSS, as well as a combination of them. It finally discusses other features available from the RISE software, such as non-smoothed CGGTTS data, adoption of satellite orbit and clock products from the IGS as well as the results of an evaluation using linear combinations with non-standard CGGTTS codes and signals.

  • 46.
    Jiang, Zhiheng
    et al.
    BIPM Bureau International des Poids et Mesures, France.
    Zhang, Victor
    NIST National Institute of Standards and Technology, USA.
    Huang, Yi-Jiun
    Telecommunication Laboratories, Chinese Taipei.
    Achkar, Joseph
    Sorbonne Université, France.
    Piester, Dirk
    PTB, Germany.
    Lin, Shinn-Yan
    Telecommunication Laboratories, Chinese Taipei.
    Wu, Wenjun
    National Time Service Center, China.
    Naumov, Andrey
    Main Metrological Center for State Service of Time and Frequency, Russia.
    Yang, Sung-hoon
    Korea Research Institute of Standards and Science, South Korea.
    Nawrocki, Jerzy
    Space Research Center Astrogeodynamic Observatory, Poland.
    Sesia, Ilaria
    Istituto Nazionale di Ricerca Metrologica, Italy.
    Schlunegger, Christian
    Federal Institute of Metrology METAS, Switzerland.
    Yang, Zhiqiang
    National institute of Metrology, China.
    Fujieda, Miho
    NICT National Institute of Information and Communications Technology, Japan.
    Czubla, Albin
    Central Office of Measures, Poland.
    Esteban, Hector
    ROA Real Instituto y Observatorio de la Armada, Spain.
    Rieck, Carsten
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Whibberley, Peter
    NPL National Physical Laboratory, UK.
    Use of software-defined radio receiversin two-way satellite time and frequencytransfers for UTC computation2018Inngår i: Metrologia, ISSN 0026-1394, E-ISSN 1681-7575, Vol. 55, s. 685-698Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two-way satellite time and frequency transfer (TWSTFT) is a primary technique for thegeneration of coordinated universal time (UTC). About 20 timing laboratories around theworld continuously operate TWSTFT using satellite time and ranging equipment (SATRE19)modems for remote time and frequency comparisons in this context. The precision of theSATRE TWSTFT as observed today is limited by an apparent daily variation pattern (diurnal)in the TWSTFT results. The observed peak-to-peak variation have been found as high as 2 nsin some cases. Investigations into the origins of the diurnals have so far provided no completeunderstanding about the cause of the diurnals. One major contributor to the diurnals, however,could be related to properties of the receive part in the modem. In 2014 and 2015, it wasdemonstrated that bypassing the receive part and the use of software-defined radio (SDR) receivers in TWSTFT ground stations (SDR TWSTFT) instead could considerably reduce boththe diurnals and the measurement noise.In 2016, the International Bureau of Weights and Measures (BIPM) and the ConsultativeCommittee for Time and Frequency (CCTF) working group (WG) on TWSTFT launched a pilotstudy on the application of SDR receivers in the TWSTFT network for UTC computation.The first results of the pilot study were reported to the CCTF WG on TWSTFT annualmeeting in May 2017, demonstrating that SDR TWSTFT shows superior performancecompared to that of SATRE TWSTFT for practically all links between participating stations.In particular, for continental TWSTFT links, in which the strongest diurnals appear, the useof SDR TWSTFT results in a significant suppression of the diurnals by a factor of betweentwo and three. For the very long inter-continental links, e.g. the Europe-to-USA links wherethe diurnals are less pronounced, SDR TWSTFT achieved a smaller but still significant gainof 30%. These findings are supported by an evaluation of some of the links with an alternatetechnique based on GPS signals (GPS IPPP) as reported in this paper.Stimulated by these results, the WG on TWSTFT prepared a recommendation for the 21stCCTF meeting, which proposed the introduction of SDR TWSTFT in UTC generation. WithCCTF approval of the recommendation, a roadmap was developed for the implementationof SDR TWSTFT in UTC generation. In accordance with the roadmap, most of the stationsthat participated in the pilot study have updated the SDR TWSTFT settings to facilitatethe use of SDR TWSTFT data in UTC generation. In addition, the BIPM conducted a finalevaluation to validate the long-term stability of SDR TWSTFT links, made test runs using theBIPM standard software for the calculation of UTC, now including SDR TWSTFT data, andstarted to calculate SDR TWSTFT time links as backup from October 2017. The use of SDRTWSTFT in UTC generation will begin in 2018.

  • 47.
    Jiang, Zhiheng
    et al.
    BIPM Bureau International des Poids et Mesures, France.
    Zhang, Victor S.
    NIST National Institute of Standards and Technology, USA.
    Huang, Yi Jiun
    TL National Standard Time and Frequency Laboratory, Taiwan.
    Achkar, Joseph
    Observatoire de Paris, France.
    Piester, Dirk
    PTB Physikalisch-Technische Bundesanstalt, Germany.
    Lin, Shinn Yan Calvin
    TL National Standard Time and Frequency Laboratory, Taiwan.
    Wu, Wenjun
    NTSC National Time Service Center, China.
    Naumov, Andrey
    Main Metrological Center for State Service of Time and Frequency, Russia.
    Yang, Sunghoon
    KRISS: Korea Research Institute of Standards and Science, South Korea.
    Nawrocki, Jerzy
    AOS Space Research Center, Poland.
    Sesia, Ilaria
    INRIM Istituto Nazionale di Ricerca Metrologica, Italy.
    Schlunegger, Christian
    Metas Federal Institute of Metrology, Switzerland.
    Yang, Zhiqiang
    NIM National Institute of Metrology, China.
    Fujieda, Miho
    NICT National Institute of Information and Communications Technology, Japan.
    Czubla, Albin
    Central Office of Measures, Poland.
    Esteban, Hector
    Real Instituto y Observatorio de la Armada, Spain.
    Rieck, Carsten
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Whibberley, Peter B.
    NPL National Physical Laboratory, UK.
    Use of software-defined radio receivers in two-way satellite time and frequency transfers for UTC computation2018Inngår i: Metrologia, ISSN 0026-1394, E-ISSN 1681-7575, Vol. 55, nr 5, s. 685-698Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two-way satellite time and frequency transfer (TWSTFT) is a primary technique for the generation of coordinated universal time (UTC). About 20 timing laboratories around the world continuously operate TWSTFT using satellite time and ranging equipment (SATRE19) modems for remote time and frequency comparisons in this context. The precision of the SATRE TWSTFT as observed today is limited by an apparent daily variation pattern (diurnal) in the TWSTFT results. The observed peak-to-peak variation have been found as high as 2 ns in some cases. Investigations into the origins of the diurnals have so far provided no complete understanding about the cause of the diurnals. One major contributor to the diurnals, however, could be related to properties of the receive part in the modem. In 2014 and 2015, it was demonstrated that bypassing the receive part and the use of software-defined radio (SDR) receivers in TWSTFT ground stations (SDR TWSTFT) instead could considerably reduce both the diurnals and the measurement noise. In 2016, the International Bureau of Weights and Measures (BIPM) and the Consultative Committee for Time and Frequency (CCTF) working group (WG) on TWSTFT launched a pilot study on the application of SDR receivers in the TWSTFT network for UTC computation. The first results of the pilot study were reported to the CCTF WG on TWSTFT annual meeting in May 2017, demonstrating that SDR TWSTFT shows superior performance compared to that of SATRE TWSTFT for practically all links between participating stations. In particular, for continental TWSTFT links, in which the strongest diurnals appear, the use of SDR TWSTFT results in a significant suppression of the diurnals by a factor of between two and three. For the very long inter-continental links, e.g. the Europe-to-USA links where the diurnals are less pronounced, SDR TWSTFT achieved a smaller but still significant gain of 30%. These findings are supported by an evaluation of some of the links with an alternate technique based on GPS signals (GPS IPPP) as reported in this paper. Stimulated by these results, the WG on TWSTFT prepared a recommendation for the 21st CCTF meeting, which proposed the introduction of SDR TWSTFT in UTC generation. With CCTF approval of the recommendation, a roadmap was developed for the implementation of SDR TWSTFT in UTC generation. In accordance with the roadmap, most of the stations that participated in the pilot study have updated the SDR TWSTFT settings to facilitate the use of SDR TWSTFT data in UTC generation. In addition, the BIPM conducted a final evaluation to validate the long-term stability of SDR TWSTFT links, made test runs using the BIPM standard software for the calculation of UTC, now including SDR TWSTFT data, and started to calculate SDR TWSTFT time links as backup from October 2017. The use of SDR TWSTFT in UTC generation will begin in 2018.

  • 48.
    Johansson, Jan
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik. Chalmers University of Technology, Sweden.
    Lidberg, Martin
    Lantmäteriet, Sweden.
    Jarlemark, Per
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Ohlsson, Kent
    Lantmäteriet, Sweden.
    Löfgren, Johan
    Chalmers University of Technology, Sweden.
    Jivall, Lotti
    Lantmäteriet, Sweden.
    Ning, Tong
    Lantmäteriet, Sweden.
    CLOSE-RTK 3: High-performance Real-TimeGNSS Services2019Rapport (Annet vitenskapelig)
    Abstract [en]

    This report presents the results from the third project of the CLOSE effort (Chalmers,Lantmäteriet, Onsala, RISE). The first project, CLOSE-RTK, investigated error sources inNetwork-RTK and simulated how to improve the performance. The results were used as a basisfor the densification, improvement and development of SWEPOS(https://swepos.lantmateriet.se/ ) during the last decade. The second project investigated how theionosphere effects the Network-RTK services.When the SWEPOS network are densified, the measurement uncertainty in the services arereduced. Thus, there is a need to continuously work in order to minimize effects from allsignificant error sources. Based on indications and experience from some 25 years operation ofSWEPOS, we have here focused on effects and error sources related to GNSS referencestations. Several new GNSS monuments are installed in the vicinity of the new Twin telescopesat the Onsala Space Observatory. Four good locations for permanent GNSS installations wereequipped with steel-grid masts serving as monuments for permanent GNSS installations. In twoof these, the installation has been untouched over a period extending over one year, while twohave been used to experiment with different installations of antennas, radomes, masthead, andthe environment of the receiving systems. The purpose of CLOSE-RTK III has been both toimprove the knowledge of the station-dependent effects in SWEPOS, and to quantify sucheffects by analyzing the collected observational data. Thus, the first work package has had theultimate goal to provide knowledge and recommendations when building a new GNSS stationand choosing the equipment to be used. The first work package also addresses the issue of somespecific station-dependent effects such as the monument stability as a function of airtemperature and sun radiation. The most important and significant results from these testsrelates to the effects of using different radomes and antennas. The influence of adding a tribrachbetween the antenna and the mast as well as adding a microwave-absorbing plate at the stationshas been investigated in detail. Furthermore, this study has looked in to the problem with birdslanding on the antennas in order to keep watch over the surrounding. A bird-detection algorithmhas been developed within the project.In second work package we investigate the necessity, and possibility, to develop methods forstation-dependent calibration in addition to the antenna-specific calibrations used to today.Since the performance of positioning services, e.g. Network-RTK, is steadily improved the errorsources related to the continuously operating reference stations may soon be limiting factors forfurther improvement of performance. Station dependent effects are thus important in highaccuracy GNSS positioning. Electrical coupling between the antenna and its near-fieldenvironment changes the characteristics of the antenna from what has been determined in e.g.absolute robot or chamber calibration.When using the presently available antenna models GNSS determination of the heightdifference between the SWEPOS pillar antennas and the surrounding reference antennas gave ~10 mm too low heights for the SWEPOS antennas. This error was derived from a comparisonwith conventional terrestrial surveys. The result varied significantly between days, and alsobetween different processing strategies. PCO/PCV errors derived from GNSS phase differencesshowed clear elevation-angle signatures that may cause systematic differences in the estimatedheight component and atmospheric delay, respectively. Electromagnetic coupling between theantenna and a metal plate below the antennas is probably contributing to the systematicPCO/PCV errors found.Starting already in 2008 and continued in this project we have developed methods andcarried out in-situ station calibration of the core permanent reference stations in SWEPOS. The station calibration intends to determine the electrical center of the GNSSantenna, as well as the PCV (phase center variations) when the antenna is installed at aSWEPOS station. The purpose of the calibration has been to examine the site-dependenteffects on the height determination as well as to establish site-dependent PCVs as acomplement to absolute calibrations of the antenna-radome pair.Our results have implications on a number of practical applications. To be mentioned isdetermination of the “local tie” between the GNSS reference point and the one from otherinstrumentation at fundamental geodetic stations. Usually, the L1 observable are used whileobserving the local GNSS networks in order to get as precise results as possible. But when usedin the IGS, the L3 (ionosphere-free) observable is used and also solving for troposphere delays.Thus, an error at the 1 cm level is easily introduced due to PCO/PCV errors.Since there are also other concepts emerging for precise real-time positioning, besides the so farused VRS-concept, the potential of these new concepts (MAC and PPP) are investigated inwork package three. Basically, the requirements from the infrastructure are invariant of thechosen concept if we aim for a certain level of performance. There is e.g. an ongoingdevelopment of real time methods for Precise Point Positioning (PPP) based on local or regionalaugmentation systems often referred to as PPP-RTK. The present development also includednew satellite signals and systems, thus, make available a three-frequency technique. The reportalso provides a schematic plan how such a service, based on PPP-RTK or rather Network-RTK,could be provided in the region of the Baltic Sea.Finally, the design of a high precision positioning service for the Baltic Sea are investigated.Motivation is that international vessel-traffic could be further optimized if the uncertainty ofvertical component in the navigation could be improved. The performance in the “Baltic Seanavigation service” would benefit from installation of some few off-shore GNSS referencestations that would be possible to locate to relatively shallow waters!

  • 49.
    Järn, Mikael
    et al.
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Grund Bäck, Lina
    RISE - Research Institutes of Sweden, Samhällsbyggnad, Byggteknik.
    Andersson, Anne
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Karlsson, Stefan
    RISE - Research Institutes of Sweden, Samhällsbyggnad, Byggteknik.
    Mesoporous sol-gel based SiO2 thin films with ordered pore orientation as antireflective coatings on glass2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Antireflective coatings on glass have increasing applications, on e.g. cover glass of PV modules, display glass, spectacle lenses or window glazing’s. Sol-gel derived mesoporous coatings can be tuned both in terms of porosity and thickness, thus allowing tuning of the refractive index. Additionally, the sol-gel approach is bottom-up, which facilitates easy upscaling. In the current work we present dip-coated mesoporous silica coatings of different pore orientation and film thickness prepared on microscope glass slides and silicon wafers. The silica coatings were derived from TEOS (tetraorthosilicates) mixed with ethanol and diluted HCl. Hexagonal and cubic pore ordering of the thin films with a pore size in the range of 5-10 nm were obtained. The thin films were characterized in terms of non-contact profilometry, stylus profilometry,  nanohardness, scratch resistance, UV-Vis-NIR transmittance and UV-Vis-NIR reflectance. The thicknesses of the studied films varied from 100 nm up to several hundreds of nm without jeopardizing the film homogeneity. All the mesoporous films exhibited higher transmittance than the uncoated glass substrate. The film with hexagonal pore orientation has a somewhat higher nanohardness than the cubic one, however,  no difference was found in the scratch resistance for the films with different pore orientations.

  • 50.
    Kampik, Marian
    et al.
    SUT Silesian University of Technology, Poland.
    Grzenik, Michał L.
    SUT Silesian University of Technology, Poland.
    Lippert, Torsten
    Trescal Ltd, Denmark.
    Rydler, Karl Erik
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Tarasso, Valter
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Trilateral Comparison of a Planar Thin-Film Thermal AC Voltage Standard in Frequency Range 1 MHz-30 MHz2018Inngår i: CPEM 2018 - Conference on Precision Electromagnetic Measurements, Institute of Electrical and Electronics Engineers Inc. , 2018, artikkel-id 8501130Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper presents results of a trilateral comparison of a travelling AC voltage standard, which was a fused-silica NIST planar multijunction thin-film thermal converter. The AC-DC voltage transfer difference of the standard was measured at 2 V and selected frequencies from 1 MHz to 30 MHz against primary thermal AC voltage standards at SUT, RISE and Trescal.

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