| 1. |
- Merlone, A., et al.
(författare)
-
The MeteoMet project - metrology for meteorology: challenges and results
- 2015
-
Ingår i: Meteorological Applications. - : Wiley. - 1350-4827 .- 1469-8080. ; 22, s. 820-829
-
Tidskriftsartikel (refereegranskat)abstract
- The study describes significant outcomes of the Metrology for Meteorology' project, MeteoMet, which is an attempt to bridge the meteorological and metrological communities. The concept of traceability, an idea used in both fields but with a subtle difference in meaning, is at the heart of the project. For meteorology, a traceable measurement is the one that can be traced back to a particular instrument, time and location. From a metrological perspective, traceability further implies that the measurement can be traced back to a primary realization of the quantity being measured in terms of the base units of the International System of Units, the SI. These two perspectives reflect long-standing differences in culture and practice and this project - and this study - represents only the first step towards better communication between the two communities. The 3 year MeteoMet project was funded by the European Metrology Research Program (EMRP) and involved 18 European National Metrological Institutes, 3 universities and 35 collaborating stakeholders including national meteorology organizations, research institutes, universities, associations and instrument companies. The project brought a metrological perspective to several long-standing measurement problems in meteorology and climatology, varying from conventional ground-based measurements to those made in the upper atmosphere. It included development and testing of novel instrumentation as well as improved calibration procedures and facilities, instrument intercomparison under realistic conditions and best practice dissemination. Additionally, the validation of historical temperature data series with respect to measurement uncertainties and a methodology for recalculation of the values were included.
|
|
| 2. |
- Ebenhag, Sven-Christian, 1976, et al.
(författare)
-
Measurements and Error Sources in Time Transfer Using Asynchronous Fiber Network
- 2010
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - 1557-9662 .- 0018-9456. ; 59:7, s. 1918-1924
-
Tidskriftsartikel (refereegranskat)abstract
- We have performed time transfer experiments basedon passive listening in fiber optical networks using Packet over synchronous optical networking (SONET)/synchronous digital hierarchy(SDH). The experiments have been performed with differentcomplexity and over different distances. For assessmentof the results, we have used a GPS link based on carrier-phase observations. On a 560-km link, precision that is relative to the GPS link of
|
|
| 3. |
- Ebenhag, Sven-Christian, 1976, et al.
(författare)
-
Time Transfer over a 560 km Fiber Link
- 2008
-
Ingår i: EFTF 2008 - 22nd European Frequency and Time Forum. ; , s. Paper E5A04 -
-
Konferensbidrag (refereegranskat)
|
|
| 4. |
- Ebenhag, Sven-Christian, 1976, et al.
(författare)
-
TIME TRANSFER USING AN ASYNCHRONOUS COMPUTER NETWORK: RESULTS FROM A 500 KM BASELINE EXPERIMENT
- 2007
-
Ingår i: Topical Meeting on Precise Time and Time Interval, 27-30/11, Long Beach, CA.
-
Konferensbidrag (refereegranskat)abstract
- SP Technical Research Institute of Sweden and STUPI have performed a time transferexperiment over a 500km long baseline between Borås and Stockholm. The time transfertechnique passively utilizes the data bit stream generated in an optical fiber computer networkbased on the packet over SONET/SDH technique. A small fraction of the optical signal ismonitored both at the transmitter and at the receiver. When an occurrence of a unique bitsequence of the SDH frames is detected, an electrical pulse is generated and compared with aresolution of 100 ps to a local clock. With data from all four positions of an optical bidirectionallink, two-way time-transfer can be achieved and any symmetrical variations in delay canpotentially be cancelled. The results presented here have been obtained over OptoSUNET, thenew Swedish University Network. In the experiment, 10 Gbit/s traffic from SP over OptoSUNETis extended in Stockholm to STUPI, a clock laboratory which is the second node in this setup.This reconnection enables that a communication channel is established between two nodes,with no intermediate jump. The time-transfer experiment includes more than 500 km of fibertransmission, of which several km is via air-lines. By comparing the results from a GPS carrierphaselink, a precision better than ± 1 ns is achieved over several months of measurementsbetween two Hydrogen-masers.
|
|
| 5. |
- Ebenhag, Sven-Christian, 1976, et al.
(författare)
-
Time transfer using an asynchronous computer network: Results from three weeks of measurements
- 2007
-
Ingår i: European Frequency and Time Forum, 29/5 - 1/6, Geneva, CH.
-
Konferensbidrag (refereegranskat)abstract
- We have performed a time transfer experimentbetween two atomic clocks, over a distance of approximately 75km using an 10 Gbit/s asynchronous fiber-optic computernetwork. The time transfer was accomplished through passivelistening on existing data traffic and a pilot sequence in the SDHbit stream. In order to assess the fiber-link clock comparison, wesimultaneously compared the clocks using a GPS carrier phaselink. The standard deviation of the difference between the twotime transfer links over the three-week time period was 243 ps.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Hedekvist, Per Olof E, 1967, et al.
(författare)
-
Accurate time transfer utilizing the synchronization in an SDH-network
- 2006
-
Ingår i: 2006 Optical Fiber Communication Conference, and the 2006 National Fiber Optic Engineers Conference; Anaheim, CA; United States; 5 March 2006 through 10 March 2006. - 9781557528032
-
Konferensbidrag (refereegranskat)abstract
- A nationwide system for accurate time distribution is being developed, utilizing synchronization in an SDH-network. The first experimental results based on this technique are presented, performed on, but not limited to, STM-64.
|
|
| 10. |
|
|
