Transcript Document

Status report: current and
future activities at NMIA
Michael Wouters, NMIA
Laurie
Besley
Chief Metrologist
& CEO
Peter
Fisk
General Manager,
Physical Metrology
Michael
Bruce
Wouters
Warrington
Project Leader
T&F
GPSCV time transfer systems
Development work continues, to add an internal
GPSDO, FPGA-based timing electronics and a
hardware clock for NTP.
Installed systems
All systems are operated under yearly contracts to provide reporting services
Frequency
standards
Time servers
Time auditors
Outputs
Frequency
traceable to
UTC(AUS)
NTP time traceable
to ±2 µs
Time validated to ± 0.1 ms (LAN) to ±100
ms (WAN).
Customers
Calibration
laboratories
Telecoms,
government,
financial markets
Transportation, vehicle speed
enforcement, government
Installation base
Four customers, 5
systems
Four customers, 8
systems
Three customers, 5 systems
Point-to-point speed enforcement
v=Δx/Δt
NTP
v=Dx/Δt
With Δx= 10 km, at 100 km/hr,
Δt ~ 360 s so ±1 km/hr
accuracy requires
synchronization to ±3 s
GPSCV
UTC(AUS)
RF dissemination via optical fibre
80 MHz analog system
Master
20 MHz digital system
Slave
Yabai He (NMI)
Magnus Hsu (NMI)
Mal Gray (NMI)
Latest tests at ANU, Canberra
ANU
ICON: Inter-governmental Communications Network
~100 km loop of dark, multi-core fibre
Loops available in various lengths and combinations.
Most recent tests were a comparison of the analog and digital rf transfer
on loops up to 150 km long.
About to test bidirectional amplifiers to demonstrate readiness for the
next milestone.
Next fibre transfer demonstration
ATCA, Narrabri
MOPRA, Coonabarabran
25 km
30 km
80 km
Very Long Baseline Interferometry (VLBI)
This link will require bi-directional amplifiers.
Aim is demonstrate practical use for VLBI.
Images: CSIRO
error (ns)
Time transfer via optical fibre
± 100
ps
PRN ranging technique,
implemented on FPGA.
cable delay (ns)
Slow progress, but in the next month or two
we will be testing this on a fibre link.
The National Time and
Frequency Network
Seeking funding to establish infrastructure for dissemination of time
and RF and optical reference signals.
Image: Andre Luiten, UWA
National Measurement Institute
Bradfield Road
West Lindfield NSW 2070
Australia
Phone: +61 2 8467 3501
Email: [email protected]
Web: www.measurement.gov.au/time