Transcript Document

WG on GNSS Report 2012
APMP Technical Committee on Time and Frequency
Wellington, New Zealand
26 November 2012
Yasuhisa Fujii
National Metrology Institute of Japan (NMIJ)
Jia-Lun Wang
National Time and Freq. Standards Lab,Taiwan (TL)
Michael Wouters and Bruce Warrington
National Measurement Institute, Australia (NMIA)
Working Group on GNSS
Mission
To support time and frequency applications of Global
Navigation Satellite Systems (GNSS) in APMP

Objectives


Coordinate GNSS time and frequency comparisons
within APMP
Develop support for new GNSS techniques and
applications
Support research into GNSS time and frequency
transfer
Coordinator: Michael Wouters (NMIA)
Sub-coordinators: Jia-Lun Wang (TL) and Yasuhisa Fujii (NMIJ)
1.1 GNSS receiver comparisons
Work program
Outcome
Circulate the TL
dual frequency receiver
More frequent comparisons
Circulate the NMIJ
single frequency receiver
Extend the dual frequency
comparison to L1/L2 delays
Support for P3 and PPP
time links
Formal recognition
Develop formal protocols
for the comparisons
Reduction of uB
1.2 GNSS receiver comparisons
Work program
Circulate the TL
dual frequency receiver
Circulate the NMIJ
single frequency receiver
Extend the dual frequency
comparison to L1/L2 delays
Develop formal protocols
for the comparisons
Progress
The dual-frequency system completed three
main rounds throughout the region and a side
visit to NMISA in South Africa.
Final reporting of results has been delayed
by the decision to do this according to a
recognized protocol.
Further comparison rounds have also been
delayed until a protocol has been adopted
and recognized.
1.3 GNSS receiver comparisons
Work program
Circulate the TL
dual frequency receiver
Circulate the NMIJ
single frequency receiver
Extend the dual frequency
comparison to L1/L2 delays
Develop formal protocols
for the comparisons
Progress
More than half of the TAI links within
APMP are now based on PPP with
geodetic receivers.
Currently calculate and report the L1
C/A code delay only. Delay values are
also available in principle for both P/L1
and P/L2, to support P3 (code) time
transfer for geodetic dual-frequency
receivers
1.4 GNSS receiver comparisons
Work program
Circulate the TL
dual frequency receiver
Circulate the NMIJ
single frequency receiver
Extend the dual frequency
comparison to L1/L2 delays
Develop formal protocols
for the comparisons
Progress
APMP TCTF and WG GNSS previously
identified the importance of a formal protocol,
to ensure recognition of results (for example, to
support reduction of uB for laboratories
contributing to TAI).
A working group was formed to prepare a draft
protocol, including representatives from BIPM,
PTB (Andreas Bauch) and NMIA (Bruce
Warrington).
To make progress, the technical details have
been separated from the full protocol. The draft
technical protocol will be introduced in the GPS
receiver calibration tutorial tomorrow.
Volunteers to help with
preparation of the protocol
will be welcomed !
Food for thought
Dec 2011 GPS calibration questionnaire
Lab
Desired cals
Receiver
SF
Last cal
uB (ns)
Link
Oct 2010
5.2
GPSPPP
Jun 2009
4.6
TWGPPP
Dec 2009
5.2
GPS P3
?
Mar 2010
5.3
GPSPPP
?
Jun 2012
7.2
GPSPPP
?
Dec 2011
5.0
TWGPPP
DF
PPP
NMI
Javad Euro-160,Septentrio PolaRx3
NICT
Septentrio PolaRx2, PolaRx2e
NIM
Javad Euro-160, Septentrio,GTR-50
SG
TTS-3, Septentrio
NPLI
TTS-2,Septentrio
TL
Z12T,Ashtec
KRISS
Z12T, Ashtec
Aug 2005
5.0
GPSPPP
NMISA
Septentrio PolaRx3TR
Aug 2004
19.9
GPS P3
VMI
Topcon Euro-80,Septentrio PolarX3TR
Aug 2004
20.1
GPS P3
MSL
Topcon Euro-80
Aug 2004
20
GPS P3
NIMT
Topcon, Oncore
Aug 2004
20
GPS P3
NMIJ
Z12T,Ashtec
Aug 2004
5.2
GPSPPP
KIM-LIPI
TTS-3,Oncore
Sep 2006
20.1
GPS MC
?
?
Circular T October 2012
2. Support for new GNSS techniques
and applications
GNSS time and frequency transfer for remote calibration
 Survey remote calibration activities within the APMP
 Provide an opportunity to discuss related issues such as the
estimation of uncertainty, the use of GNSS-disciplined
oscillators, and accreditation of calibration services
 Report back to the APMP TCTF, summarising information
which may be useful to economies operating or developing
remote calibration facilities
 Consider guidelines for harmonization/standardisation of
remote calibration services, and for the assessment of these
services for CMCs under the CIPM MRA
The WG is especially grateful for the leadership of Michito Imae of NMIJ in
this work
3. Support research into GNSS time
and frequency transfer
At the recent CCTF meeting, the outgoing
chair of the Working Group on GNSS Time
Transfer Standards, Dr Judah Levine (NIST),
recommended:
“... the ongoing development of standardised
time-transfer hardware, open sharing of
receiver firmware and processing software,
and greater automation of laboratory
comparisons”.
Tutorial session
Calibration of time-transfer receivers
 Report on BIPM calibration visit (NIM)
 Report on BIPM calibration visit (NMIA)
 Lab demonstration
(TL)
 Calibration data analysis
Introduction to the draft technical protocol
Sample analysis
A few case studies - noisy data etc
Take away exercise
Resources
 Future plans for the WG on GNSS
 Q&A
Thanks to Huang-Tien Lin (TL) for organizing this session
National Measurement Institute
Bradfield Road
West Lindfield NSW 2070
Australia
Phone: +61 2 8467 3501
Email: [email protected]
Web: www.measurement.gov.au/time