REPORT OF TIME AND FREQUENCY LABORATORY (VIETNAM METROLOGY INSTITUTE)

Transcription

1 Nguyen Bang Head of Time and Frequency Laboratory (TFL) Vietnam Metrology Institute (VMI) N 0 8, Hoang Quoc Viet Road, Caugiay District, Hanoi, Vietnam

2 About Time & Frequency Laboratory (TFL) Time and Frequency Laboratory within Vietnam Metrology Institute (VMI). The Lab is a highest laboratory in the fields of Time and frequency in Vietnam testing measurement calibration scheme. + There are 7 staffs working at the TFL; + The laboratory has been accredited in accordance with ISO/IEC 17025:2005 by Vietnam Laboratory Accreditation Scheme (VILAS);

3 Main activities of Time & Frequency Laboratory (TFL) Currently, main activities of TFL are the maintenance of national time scale [UTC (VMI)] and its dissemination through calibration services. Namely: + Maintenance of UTC (VMI) + Time comparison via satellites + Dissemination of standard time and frequency

4 1. Maintenance of UTC (VMI) In time and frequency laboratory of VMI, the 5 MHz frequency from Symmetricom 5071A (high-performance tube) is used as the external reference for AOG (Auxiliary Output Generator) and output of 1 PPS and 5 MHz from the AOG are defined as UTC (VMI) and Vietnam standard Frequency (VSF), respectively. UTC (VMI) is maintained with the help of highperformance 5071A Cesium clocks. It is generated by following BIPM tracking schedule for time comparisons via GPS commonview. For dissemination, it is maintained less than 100 ns of UTC. The Vietnam Standard Time is then defined as: UTC (VMI) + 7h

5 1. Maintenance of UTC (VMI) UTC(VMI) data from Circular-T Frequency adjusting (UTC-trace as required) Antenna Pulse Dis. Amp. 6602B 1PPS 5MHz GPS receivers (Javad EU-80, Septentrio PolarRx3eTR) Cs 5071A (± ) Option 001 (Symmetricom) Cs 5071A (± ) (Symmetricom) 5MHz 1PPS 5MHz 1PPS AOG-110 Auxiliary Output Generator 1PPS TSC Time difference between clocks UTC(VMI) 1PPS VSF (5MHz) RF. Distribution Amp. 6502B Algorithm Ensemble atomic time PC GPS data send to BPPM Cs 5071A (± ) (HP 5071A) TSC-4077 Clocks data send to BIPM UTC(VMI) - TA(VMI) data Fig 1.1 Clock comparison system traceable to BIPM To BIPM Time and Gravimetry

6 1. Maintenance of UTC (VMI) UTC (VMI) is maintained with the help of high-performance 5071A Cesium clocks. It is generated by following BIPM tracking schedule for time comparisons via GPS commonview. For dissemination, it is maintained less than 100 ns of UTC. The Vietnam Standard Time is then defined as: UTC (VMI) + 7h The three atomic clocks have been compared with one another by the TSC This comparison is performed daily at UTC 0 h (VST + 7 h). We send the collective data to the BIPM time section monthly. The traceability of VST and VSF based on the data of BIPM Circular-T

7 2. Time comparison via satellites There are two systems used to GPS common view time transfers at the TFL as Javad EU-80 and Septentrio PolarRx3 systems. To retain the traceability of VST and VSF, the timecomparison data using the GPS satellite are sent to BIPM every month. At the same time, we send RINEX files of the Septentrio PolarRx3 receiver to BIMP daily. The reported data of (UTC UTC (VMI)) in Circular-T are checked regularly.

8 Comparison result GPS receiver SeptentrioPolaRx3TR

9 Comparison result of UTC-UTC(VMI) from to 55800

10 3. Dissemination of standard time and frequency 3.1 Dissemination of time in Vietnam - Standard time of UTC (VMI) is broadcasting though the radio the voice of Vietnam at 6:00, 12:00, 18:00, and 21:00 every day. - Time services though the internet: Standard time of UTC (VMI), we used the Sync Server S250i of Symmetricom (USA) to disseminate on the Website:

11 3. Dissemination of standard time and frequency 3.2 Calibration services Officially, we have been providing frequency calibration/ testing services for universal counters, signal generators, local clocks, local frequency standards and the time interval from 0.01s, GPS receiver, Stop-watches, Tachometers, National technical regulation on automobile tachograph In house computer programs have been written for the various types of counters and frequency measuring equipments used.

12 3. Dissemination of standard time and frequency 3.2 Calibration services

13 4. Other activities: + We have succeeded in the research, design, manufacture some equipments such as: tachometer; standard for verification of taximeters, + To develop calibration/ testing methods.

14 5. Future development plan - To develop remote calibration services; - To strengthen international and bilateral comparison with other NMIs in time and frequency field; - To develop dissemination of time in Vietnam through NTP server, speaking clock - To research and prepare any conditions to participate the program of experiment on rapid UTC of BIPM. - To continue research and application on time scale algorithm to steer of UTC(VMI) by UTC. - To built the TA (VMI).

15 Thank you for your attention!