Upgradation and Strengthening of National Time Scale of India

Transcription

1 Upgradation and Strengthening of National Time Scale of India (ATF 2017) Ashish Agarwal, P. Thorat, M. P. Olaniya, S. Yadav, P. Kandpal, P. Arora, S. Panja, S. De, T. Bharadwaj, N. Sharma, S. Kazim, B. Ehtesham, V. N. Ojha and D. K. Aswal 1

2 Outline Generation of UTC(NPLI) Performance of UTC(NPLI) Objectives of the Upgradation Users of Indian Standard Time Dissemination of UTC(NPLI) Internet Web Time Display Telephone line TWSTFT Backup Time Scale Concluding Remarks

3 NIST PTB NPLI Others ~400 atomic clocks Cesium Fountain Primary Frequency Standards NPL s contribution to generation of UTC Calibration Free Atomic Time (EAL) International Atomic Time (TAI) Leap seconds Coordinated Universal Time (UTC) UTC (NPLI) IST=UTC (NPLI)+5:30 Teleclock ~1 s NTP Server ~100 ms CVGNSS & TWSTFT ~ 20 ns Parliament House IR IAF NIC-NKN CCA IDRBT SBI ISRO

4 NIST PTB NPLI Others ~400 atomic clocks Cesium Fountain Primary Frequency Standards NPL s contribution to generation of UTC Calibration Free Atomic Time (EAL) International Atomic Time (TAI) Leap seconds Coordinated Universal Time (UTC) UTC (NPLI) IST=UTC (NPLI)+5:30 FonOclock ~10 m s NTP Server ~100 ms CVGNSS & TWSTFT ~ 20 ns Parliament House IR IAF NIC-NKN CCA IDRBT SBI ISRO

5 10 MHz out out out Schematics of Generation of UTC(NPLI) To Fountain Lab Active Hydrogen Maser - HM1 MHM MHz 1 PPS IN 5 MHzout Distribution Amplifier-1 5 MHz IN Micro Phase Stepper 5 MHz UTC(NPLI) FREQUENCY DOUBLER Cs Clock A-C001 Cs Clock A-C001 Cs Clock A-C001 Cs Clock A-C001 Cs Clock A-C001 Automatic Switching Unit START START STOP Time interval counter (25psec resolution) - - Controller Workstation To Satellite Links PHM

6 Temperature ±1.2 C UTC- UTC(NPLI), ns 40 Performance of UTC (NPLI ) Environmental conditions in laboratory degraded New Environmental Control system commissioned in Aug MJD /9/ /10/ MJD Large temperature variation

7 BIPM Weights of Cesium Clocks of NPLI Performance shows aging of Atomic clocks Two new Cesium Clocks and one Passive Hydrogen Maser installed.

8 10 MHz Data Schematics of GNSS and TWSTFT Links 10 MHz GTR51-A Rx 10 MHz GTR51-B Rx Saw Filter 2.5MHz Antenna Control unit 10 MHz TTS4 Rx Beacon Receiver 10 MHz PolaRx3eTR Rx Workstation for controlling SATRE MODEM operation Workstation for controlling GNSS Rx operation 10 MHz Distribution Amplifier-2 10 MHz To Calibration Lab

9 Atomic Clocks and Satellite links at NPLI Clock Setup GNSS Rx Setup TWSTFT Setup 9

10 Upgradation of Primary Time Scale Two New Cesium Clocks started contributing to International Time Scale, UTC. Environmental control system upgraded. Three more Cesium Clocks will be installed during April One additional Hydrogen Maser to be installed during December 2018 and will provide the desired stability to the time scale. Current uncertainty of ±20 ns to be reduced by calibration of GNSS receivers. Leap second was added at UTC 23:59:59 on December 31, 2016.

11 Data and Network Security Architecture

12 Objective of Upgradation To cater to the national needs of e-governance and disaster management, digital financial transactions, digital archiving, and time stamping, satellite navigation, smart power grid, cyber security and internet of things, communication systems, improved transportation, National Security and radar synchronisation.

13 MoU signed with ISRO for time and frequency traceability services on August 4, 2017

14 Dissemination of IST with 1 ns uncertainty wrt UTC(NPLI) established via Two-way Satellite Time Transfer link to ISRO. NPL ISTRAC Bangalore

15 Dissemination of Indian Standard Time (IST) Service from CSIR-NPL Protocol Uncertainty Users Internet Time Service Network Time Protocol (NTP) Teleclock Landline Mobile 100 ms 1 s 1 s AADHAR, SHCIL, NIC, CSIR-NPL, All computers with internet Parliament, Railways, Airports, Ministries in central and state Govt. Fonoclock Landline 10 ms Same as above Important users:

16 IST dissemination through Web

17 Network Time Displays in NPL Campus

18 Backup Time Scale Laboratory

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21 Concluding Remarks Long wave Radio (LWR) based transmission infrastructure to disseminate Indian Standard Time across India is planned. Creation of Secondary Time Scales in different metros planned. ISRO s Indian Regional Navigational Satellite System (IRNSS), also called Navik is traceable to CSIR-NPL using CV-GNSS and TWSTFT techniques. Synchronization of pan-india Information Technology network of Government of India under progress. Time Synchronisation system being setup at NIC-NKN locations in New Delhi and Hyderabad Telephone time dissemination service being upgraded in the form of Fonoclock service with better accuracy.

22 Thank you for your attention