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Hedekvist, P. O., Ebenhag, S.-C., Rieck, C., Wallberg, D. & Bergroth, M. (2022). Fiber Optic Time Transfer from UTC(k) to a VLBI Antenna in a Coherent Communication Network. In: 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022 - Proceedings: . Paper presented at 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022, 24 April 2022 through 28 April 2022. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Fiber Optic Time Transfer from UTC(k) to a VLBI Antenna in a Coherent Communication Network
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2022 (English)In: 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2022Conference paper, Published paper (Refereed)
Abstract [en]

The local time scale at Onsala Space Observatory is connected to UTC(SP) through a White Rabbit time transfer system operating on the Swedish University Computer Network SUNET. The time transfer enables a robust synchronization of the VLBI and the IGS stations operating at the observatory and can potentially improve the reliability and availability of traceable time at sufficient accuracy. Several months of data are gathered to evaluate long term events and stability metrics. 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2022
Keywords
fiber, synchronization, time dissemination, WDM, White rabbit, Observatories, Coherent communication, Communications networks, Fiber-optics, Local time, Onsala Space Observatory, Time transfer, Time-scales, Transfer systems, Computer operating systems
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-60159 (URN)10.1109/EFTF/IFCS54560.2022.9850949 (DOI)2-s2.0-85137355028 (Scopus ID)9781665497183 (ISBN)
Conference
2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022, 24 April 2022 through 28 April 2022
Note

Funding details: Horizon 2020 Framework Programme, H2020; Funding details: Horizon 2020; Funding text 1: This work was supported by the TiFOON 18SIB06 Project through the EMPIR Programme co-financed by the Participating States and through the European Union’s Horizon 2020 Research and Innovation Program.; Funding text 2: This work was supported by the TiFOON 18SIB06 Project through the EMPIR Programme co-financed by the Participating States and through the European Union's Horizon 2020 Research and Innovation Program.

Available from: 2022-10-10 Created: 2022-10-10 Last updated: 2023-06-08Bibliographically approved
Alissa, S., Håkansson, M., Rieck, C., Dutta, U., Nord, S., Bergljung, P. & Bagge, A. (2021). Distribution of the adapted-NRTK correction data via VDES for the shipping navigation safety. In: Proceedings of the 34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021: . Paper presented at 34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021, 20 September 2021 through 24 September 2021 (pp. 521-534). Institute of Navigation
Open this publication in new window or tab >>Distribution of the adapted-NRTK correction data via VDES for the shipping navigation safety
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2021 (English)In: Proceedings of the 34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021, Institute of Navigation , 2021, p. 521-534Conference paper, Published paper (Refereed)
Abstract [en]

In this study the maritime communication system VDES (VHF Data Exchange System) is proposed to distribute Network-RTK (NRTK) correction data to shipborne GNSS receivers in fairways, port areas, or inland water ways. The transport layer used for transmission of VDES messages (related to the standard IEC61162-450) is the UDP multicast protocol. This makes it possible to transmit the RTCM packages from the VDES transponder to the shipborne GNSS receivers as a UDP payload without any additional formatting. In order to minimize the impact on the overall VDES data capacity in a local service area, NRTK correction data shall at most occupy a single VDES slot with a net capacity of 650 bytes denoted Link ID 19. This is the fastest link in VDES. Update rates may vary but are preferably at 1Hz. However, depending on the number of visible satellites NRTK correction data size changes instantly and the data rate can therefore sometimes be in excess of 1000 byte/s per reference station to be distributed. In order to comply with the VDES requirements, the Lantmäteriet Adjustment Solution (LAS) for GNSS correction data adjustment was developed and is presented in this paper. The responsibility of this solution is to produce a correction data stream that complies with the bandwidth limitation of 650 bytes/s. To provide corrections for a potentially large number of users, dissemination is done by broadcasting corrections for a grid of VRSs. The proposed solution has therefore also the capability to combine several correction data streams from several Virtual Reference Stations (VRSs) into one single correction data stream. To reduce the required data rate, the LAS has the ability to filter streamed GNSS correction data in the RTCM3 MSM format constellation-wise, satellite-wise, and signal-wise. The objective is to achieve optimal performance in terms of accuracy for the ship's differential positioning solution, while at the same time adhering to constraints that might locally apply for individual transmitters. For this paper LAS was configured to interface with the SWEPOS to provide reference data to static and kinematic testing scenarios. The results presented here were obtained using RTK post-processing with RTKLib for a combination of GPS and Galileo multi-frequency observations. Results indicated that LAS solution can achieve robust positioning performance with decimeter-level accuracy which meet the requirements expected for the navigation safety at Sea. Adapted-NRTK correction data (LAS data) via VDES has the potential to be part of a world-wide standard VDES application for all vessels sailing under SOLAS and for ships that voluntarily uses VDES in the near future (inland, yachts, navies, leisure).

Place, publisher, year, edition, pages
Institute of Navigation, 2021
National Category
Signal Processing
Identifiers
urn:nbn:se:ri:diva-57955 (URN)10.33012/2021.18142 (DOI)2-s2.0-85120911143 (Scopus ID)9780936406299 (ISBN)
Conference
34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021, 20 September 2021 through 24 September 2021
Note

Funding details: Horizon 2020 Framework Programme, H2020, 870239; Funding details: Horizon 2020; Funding text 1: ?This work has received funding from the European Union Agency for the Space Programme under the European Union's Horizon 2020 research and innovation programme under grant agreement No 870239?.; Funding text 2: “This work has received funding from the European Union Agency for the Space Programme under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 870239”.

Available from: 2022-01-12 Created: 2022-01-12 Last updated: 2023-05-10Bibliographically approved
Rieck, C., Jarlemark, P., Nord, S., Alissa, S. & Gunnarsson, F. (2021). Harmonization of NPRS observations for a seamless RTK positioning service in automated driving applications. In: Proceedings of the 34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021: . Paper presented at 34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021, 20 September 2021 through 24 September 2021 (pp. 402-423). Institute of Navigation
Open this publication in new window or tab >>Harmonization of NPRS observations for a seamless RTK positioning service in automated driving applications
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2021 (English)In: Proceedings of the 34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021, Institute of Navigation , 2021, p. 402-423Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Institute of Navigation, 2021
National Category
Communication Systems
Identifiers
urn:nbn:se:ri:diva-57956 (URN)10.33012/2021.17887 (DOI)2-s2.0-85120899513 (Scopus ID)9780936406299 (ISBN)
Conference
34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021, 20 September 2021 through 24 September 2021
Note

Funding text 1: The NPAD project (2018-2020) was funded by Vinnova FFI – Electronics, Software and Communication.

Available from: 2022-01-12 Created: 2022-01-12 Last updated: 2023-05-10Bibliographically approved
Nord, S., Tidd, J., Gunnarsson, F., Alissa, S., Rieck, C., Hanquist, C.-H., . . . Chaisset, C. (2021). NPAD - Final Report D1.3: Network-RTK Positioning for Automated Driving. Borås
Open this publication in new window or tab >>NPAD - Final Report D1.3: Network-RTK Positioning for Automated Driving
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2021 (English)Report (Other academic)
Abstract [en]

Future automated vehicles and advanced driver assistance systems are highly dependent on sensors to detect their environment as well as robust, accurate, and cost-effective sensor systems for positioning. 

Global Navigation Satellite systems (GNSS) provide a key technology that enables an absolute position estimate and Network-RTK (Real Time Kinematic) has the potential to meet the requirements of cost, accuracy, and availability. This technology is based on correction data being received from a fixed reference station via e.g. mobile communication. Current implementations have been driven by requirements from applications which operate within a limited region for lengthy periods of time, such as surveying and precision agriculture. These applications can tolerate relatively long initialization times and can afford expensive equipment.

The mass market wants to benefit from infrastructure in place for these applications, but the requirements are somewhat different. Problems occur when the device moves from the coverage area of one reference station to another and reinitialization must be made. Consumer devices must also deliver similar performance with inexpensive components. In addition to this, the existing public-sector system for distribution of correction data, in Sweden governed by Lantmäteriet/ SWEPOS, is not designed for handling a large number of clients and efficiently distributing correction data to these clients based on their location.The telecom industry in 3GPP (Third generation partnership project) is currently addressing the need for a scalable provisioning of network RTK corrections. Based on the 3GPP specification, the project aimed to develop, implement, test and demonstrate an efficient distribution system for Network-RTK correction data in order to enable cm-level accuracy GNSS positioning for a large number of mobile platforms e.g. automated vehicles.

The NPAD project has:

  • Leveraged the existing Lantmäteriet/SWEPOS GNSS reference infrastructure to implement a virtual network of reference stations that provided coverage over selected test areas suitable for supporting a large number of simultaneous users.
  • Implemented a scalable GNSS correction data provisioning based on the ongoing work in 3GPP that provides correction data from the reference network to mobile devices;
  • Developed test cases for automated vehicle platforms related to positioning and implemented demonstrators;
  • Investigated tools and methods for validating the accuracy of integrated GNSS positioning and navigation systems.

The project was coordinated by RISE Research Institutes of Sweden and involved besides Lantmäteriet and AstaZero the following industrial partners: AB Volvo, Caliterra, Einride, Ericsson, Scania, and Waysure.

Place, publisher, year, edition, pages
Borås: , 2021. p. 100
Keywords
Automated Driving, Network-RTK, NRTK, GNSS positioning, measurement technology, Real Time Kinematic, 3GPP, SWEPOS, GNSS augmentation, positioning and navigation system, reference station, positioning accuracy
National Category
Communication Systems
Identifiers
urn:nbn:se:ri:diva-52475 (URN)
Projects
NPAD
Funder
Vinnova, 2017-05498
Available from: 2021-02-22 Created: 2021-02-22 Last updated: 2023-05-10Bibliographically approved
Dutta, U., Rieck, C., Håkansson, M., Gerbeth, D., Alissa, S. & Nord, S. (2021). Satellite selection in the context of network RTK for limited bandwidth applications. In: Proceedings of the 34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021: . Paper presented at 34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021, 20 September 2021 through 24 September 2021 (pp. 2474-2492). Institute of Navigation
Open this publication in new window or tab >>Satellite selection in the context of network RTK for limited bandwidth applications
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2021 (English)In: Proceedings of the 34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021, Institute of Navigation , 2021, p. 2474-2492Conference paper, Published paper (Refereed)
Abstract [en]

The increasing number of modernized GNSS signals and the availability of multi-constellation receivers are crucial for improvements of both precision and robustness of GNSS based positioning. However, the abundance of GNSS observations is not always useable as applications, using differential positioning or other techniques, may have limitations with respect to computational resources or communication bandwidth for reference data, and therefore require a qualified selection of a subset of observations for positioning. This paper is based on the work conducted in the project PREParE SHIPS funded by the European Union Agency for the Space Programme (EUSPA) on the specific application of Maritime Navigation using Network Real Time Kinematic (NRTK) and will focus on the satellite selection algorithms of the Prepare Ships dissemination solution. This study is motivated by data rate requirements and restrictions of the VDES dissemination solution developed in Prepare Ships. The restricted data rate for dissemination of RTK observations via VDES implies the need for a qualified pre-selection of satellite subsets to match the available bandwidth and the requirements of the positioning system. For this, multiple algorithms have been developed and tested in static and dynamic scenarios. Optimization techniques for height (for vertical position), two and three dimensions were examined. Different weighting schemes were used. During the evolution of the satellite selection study, it was concluded that it is necessary to retain satellites with the highest elevation as this will empirically improve integer ambiguity resolution for position fixing. Also fixing a minimum number of satellites for each constellation was required to enable a fair weightage to the different constellations used. Such algorithms should prove to be very useful for research on various Network RTK applications which require/prefer limited bandwidth such as for cadastral surveying and mapping, for airborne geo-referencing of aerial mapping data using Unmanned Aerial Vehicles (UAV) and on the road and sea for positioning and navigation of automated transport. Additionally, these algorithms could also be extended to consider satellite visibility in e.g. urban areas (i.e. urban canyons) by inclusion of true surface information for more robust GNSS positioning in automated transport applications [1]. This could either be for pre-evaluation or for dynamically considering spatial information. While this work is a part of PREParE SHIPS, it is also motivated by a more general applicability of the algorithms presented for other similar applications. RTK correction dissemination with limited bandwidth requirements is very promising for RTK research and therefore this study on optimized selection of satellite subsets is of vital importance and could tap multiple opportunities of huge potential such as those involving NRTK or combination of Precise Point Positioning with RTK. © 2021 Proceedings of the 34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021. 

Place, publisher, year, edition, pages
Institute of Navigation, 2021
National Category
Signal Processing
Identifiers
urn:nbn:se:ri:diva-57957 (URN)10.33012/2021.17948 (DOI)2-s2.0-85120872427 (Scopus ID)9780936406299 (ISBN)
Conference
34th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS+ 2021, 20 September 2021 through 24 September 2021
Note

Funding details: Horizon 2020 Framework Programme, H2020, 870239; Funding details: Horizon 2020; Funding text 1: This work is carried out as part of the PREParE SHIPS project [23] and has been supported by funding from the European Union Agency for the Space Programme under the European Union's Horizon 2020 research and innovation programme under grant agreement No 870239. We also acknowledge the RTKLib project initiated by Tomoji Takasu and contributed to by others, notably Tim Everett of rtkexploer.com, Dirk St?cker for the rtcm3torinex tool that was heavily abused.; Funding text 2: The increasing number of modernized GNSS signals and the availability of multi-constellation receivers are crucial for improvements of both precision and robustness of GNSS based positioning. However, the abundance of GNSS observations is not always useable as applications, using differential positioning or other techniques, may have limitations with respect to computational resources or communication bandwidth for reference data, and therefore require a qualified selection of a subset of observations for positioning. This paper is based on the work conducted in the project PREParE SHIPS funded by the European Union Agency for the Space; Funding text 3: This paper is based on the work carried out in the project PREParE SHIPS funded by European GNSS Agency (GSA) on the specific application of Maritime Navigation using Network Real Time Kinematic. VDES [15] is proposed for dissemination of these observations and potentially restricts the available data rate. Therefore, there is a need for optimal selection of satellite/signal subsets from the set of the available GNSS provided by the NRTK service. The objective of the algorithms presented in this paper is to systematically choose a combination of specific signals, satellites or even constellations that optimizes RTK positioning performance as per guidelines mentioned in [16].

Available from: 2022-01-12 Created: 2022-01-12 Last updated: 2023-05-10Bibliographically approved
Rieck, C., Gewies, S., Grundhofer, L. & Hoppe, M. (2020). Synchronization of R-Mode Base Stations. In: IFCS-ISAF 2020 - Joint Conference of the IEEE International Frequency Control Symposium and IEEE International Symposium on Applications of Ferroelectrics, Proceedings: . Paper presented at 2020 Joint Conference of the IEEE International Frequency Control Symposium and IEEE International Symposium on Applications of Ferroelectrics, IFCS-ISAF 2020, 19 July 2020 through 23 July 2020. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Synchronization of R-Mode Base Stations
2020 (English)In: IFCS-ISAF 2020 - Joint Conference of the IEEE International Frequency Control Symposium and IEEE International Symposium on Applications of Ferroelectrics, Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2020Conference paper, Published paper (Refereed)
Abstract [en]

R-Mode is an alternative maritime PNT technology currently under development. It is based on synchronous transmissions and multilateration. Base station synchronization errors are recognized as the major error source. Introduction to R-Mode using maritime radio beacons, timing requirements, and the concept of R-Mode in-band synchronization are briefly presented.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2020
Keywords
GNSS vulnerability mitigation, maritime PNT, R-Mode Baltic, Range Mode, time synchronization, Synchronization, Error sources, In-band, Radio beacons, Synchronization error, Synchronous transmission, Timing requirements, Base stations
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-51205 (URN)10.1109/IFCS-ISAF41089.2020.9234840 (DOI)2-s2.0-85096982194 (Scopus ID)9781728164304 (ISBN)
Conference
2020 Joint Conference of the IEEE International Frequency Control Symposium and IEEE International Symposium on Applications of Ferroelectrics, IFCS-ISAF 2020, 19 July 2020 through 23 July 2020
Note

Funding details: Interreg; Funding details: European Commission***Delivered and deleted from Elsevier end because this record is to be no longer updated or in business with Elsevier on Date 10-03-2020***, EC; Funding details: European Regional Development Fund, FEDER; Funding text 1: 1 The R-Mode Baltic project is co-financed by the European Union through European Regional Development Fund within the Interreg Baltic Sea Region Program.

Available from: 2021-01-11 Created: 2021-01-11 Last updated: 2023-05-10Bibliographically approved
Rieck, C., Jaldehag, K., Ebenhag, S.-C., Jarlemark, P. & Hedekvist, P. O. (2020). Time and frequency laboratory activities at RISE. In: Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI: . Paper presented at 51st Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI 2020, 21 January 2020 through 24 January 2020 (pp. 169-180). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Time and frequency laboratory activities at RISE
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2020 (English)In: Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI, Institute of Electrical and Electronics Engineers Inc. , 2020, p. 169-180Conference paper, Published paper (Refereed)
Abstract [en]

RISE Research Institutes of Sweden is since 2018 the result of a rebranding of SP Technical Research Institute of Sweden and several other national research facilities and test beds in Sweden. This also comprises most national metrology institute (NMI) activities, including time and frequency that is still located at its Borås facilities in the southwest of Sweden since 1995. UTC(SP) remains the official designation of the Swedish UTC(k) realization. It is realized in a classical master clock and phase stepper setup and is locally distributed to different users and time transfer applications. The most recent local clock ensemble consists of four hydrogen masers and three high performance 5071A Cs standards. UTC(SP) is linked to TAI using TWSTFT and GNSS. The primary link is a combination TWGPPP with current calibration uncertainties of 1.1 ns. The time scale is regularly kept within ±5 ns of UTC. RISE has also established several distributed UTC(SP) copies, with both local backups in Borås and facilities at remote sites linked together by GNSS time transfer. Network time distribution at those sites make UTC(SP) publicly available. Additionally, RISE offers several calibration services for the distribution of UTC-traceable time and frequency signals. Time and frequency related metrological research at RISE is mostly concentrated on further refinement of GNSS and TWSTFT methods, their calibration and the dissemination using those methods. We are also active in research on fiber based optical time and frequency transfer. Outside the metrological responsibilities, many research projects focus on establishing metrological aspects of time and frequency within for instance the automotive and maritime domain.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2020
Keywords
Clocks, Hydrogen masers, Time measurement, Calibration uncertainty, National metrology institutes, Research facilities, Research institutes, Technical research, Time and frequencies, Time and frequency transfers, Time distribution, Calibration
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-44903 (URN)10.33012/2020.17297 (DOI)2-s2.0-85081552388 (Scopus ID)0936406259 (ISBN)
Conference
51st Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI 2020, 21 January 2020 through 24 January 2020
Note

Funding details: National Measurement Institute, NMI; Funding details: VINNOVA; Funding text 1: RISE has inherited the function of the Swedish NMI from SP Technical Research Institute of Sweden in 2018 when the RISE institutes Innventia, Swerea, SP and Swedish ICT merged to create a stronger research and innovation partner for businesses and society. The intention is to make industrial research institutes internationally more competitive and to facilitate continued sustainable growth in Sweden by strengthening competitiveness and renewal in the business community [1]. RISE is appointed as the Swedish NMI by the Ministry of Enterprise and Innovation. The NMI is funded from Vinnova [2], Sweden’s innovation agency and any strategic decisions are made by an advisory board composed of experts from Swedish industry. Vinnova decides the level of NMI funding and also the Swedish level of participation in European funded research of the EMPIR program and its possible successor.; Funding text 2: This report was supported by the Swedish National Metrology Program, program owner Swedish Agency for Innovation Systems (VINNOVA). We acknowledge the work of the BIPM, the CCTF and EURAMET, further the Swedish Post and Telecom Authority (PTS) who finances critical Swedish communication infrastructure and thereby strengthens resiliency in national timing.

Available from: 2020-05-20 Created: 2020-05-20 Last updated: 2023-06-08Bibliographically approved
Bergstrand, S., Herbertsson, M., Rieck, C., Spetz, J., Svantesson, C.-G. & Haas, R. (2019). A gravitational telescope deformation model for geodetic VLBI. Journal of Geodesy, 93(5), 669-680
Open this publication in new window or tab >>A gravitational telescope deformation model for geodetic VLBI
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2019 (English)In: Journal of Geodesy, ISSN 0949-7714, E-ISSN 1432-1394, Vol. 93, no 5, p. 669-680Article in journal (Refereed) Published
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.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36562 (URN)10.1007/s00190-018-1188-1 (DOI)2-s2.0-85053236319 (Scopus ID)
Available from: 2018-12-06 Created: 2018-12-06 Last updated: 2023-06-08Bibliographically approved
Ebenhag, S.-C., Hedekvist, P. O., Rieck, C., Bergroth, M., Krehlik, P. & Sliwczynski, L. (2019). Evaluation of Fiber Optic Time and Frequency Distribution System in a Coherent Communication Network. In: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings: . Paper presented at 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Evaluation of Fiber Optic Time and Frequency Distribution System in a Coherent Communication Network
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2019 (English)In: 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. , 2019Conference paper, Published paper (Refereed)
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.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
fiber optics, time dissemination, traceable, Coherent communication, DWDM networks, Onsala Space Observatory, Reconfigurable optical add-drop multiplexer, Single wavelength, Time and frequencies, Fibers
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-40617 (URN)10.1109/FCS.2019.8856039 (DOI)2-s2.0-85073779075 (Scopus ID)9781538683057 (ISBN)
Conference
2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019
Note

Funding text 1: This work was supported by 15SIB05-OFTEN, which has received funding from the EMPIR programme co-financed by the Participating States within Euramet and from the European Union's Horizon 2020 research and innovation programme.

Available from: 2019-11-25 Created: 2019-11-25 Last updated: 2023-06-08Bibliographically approved
Jaldehag, K., Jarlemark, P. & Rieck, C. (2019). Further Evaluation of CGGTTS Time Transfer Software. In: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings: . Paper presented at 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Further Evaluation of CGGTTS Time Transfer Software
2019 (English)In: 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. , 2019Conference paper, Published paper (Refereed)
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. 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
CGGTTS, GNSS, Software, Time Transfer, Codes (symbols), Computer software, Global positioning system, Petroleum reservoir evaluation, Radio navigation, Linear combinations, Research institutes, Satellite navigation systems, Stand-alone software, Time and frequencies, Application programs
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-40615 (URN)10.1109/FCS.2019.8856022 (DOI)2-s2.0-85073778760 (Scopus ID)9781538683057 (ISBN)
Conference
2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019
Available from: 2019-11-26 Created: 2019-11-26 Last updated: 2023-05-23Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1710-6058

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