FINAL REPORT - Stakeholders - Ofcom

Parameter Value Notes
Service
topology
ATN
compliance
Frequency
band
Air-air
broadcast,
Uplink
broadcast,
Downlink
broadcast
No
960-1215 MHz
RF Channels Single 1 MHz
channel
Modulation
scheme
Binary GFSK
+/- 312.5 kHz
Bit rate 1.041667
Mbit/s
Channel
access
method
Frequency
availability
(allocation
status)
Dependencie
s
Currently no frequency globally available
Random Slots Ground Stations use separate slots in a predefined manner.
No operational
frequencies
currently
allocated.
Earliest
availability:
2006 (may be
longer in
Europe)
UTC time
source
Europe and the US are converging on the 978 MHz frequency.
Analysis shows that a UAT assignment at 978 or 979 MHz is
possible in the US. These frequencies are used in the US for
testing purposes, and there are no operational assignments in
that US at either frequency.
Analysis of the utilisation of the frequencies 978 and 979 MHz in
Europe shows that a number of DME and TACAN assignments
exist in Europe at these frequencies: 6 assignments at 978 MHz
and 50 assignments at 979 MHz, suggesting 978 MHz as a
possible candidate for UAT.
The deployment of UAT requires international co-ordination to
obtain a 3MHz channel in the DME band. Whilst a suitable
frequency seems likely to be available in America, the European
situation is more complex.
The ECAC Navigation Strategy foresees the long-term use of
DMEs to support GNSS in providing a harmonised area
navigation (RNAV) environment.
This will require significant deployment of new DMEs in Europe,
in particular within terminal areas. The current estimate is that
180-200 new DMEs will be required by 2010.
Requires an accurate source of UTC time, nominally from a
GNSS receiver (which may be a GPS receiver)
Other issues Security issues and potential vulnerabilities still to be assessed
by the aeronautical community.
Table 3-10: UAT summary
3.3.8.3 Prospects for ADS-B implementation
ADS-B provides a possible alternative to Mode S SSR providing position and other data.
The UK current surveillance programme involves replacement of the current SSR with
Mode S phased over the period 2003 – 2010. Hence there is little prospect that ADS-B
for air/ground surveillance will be a viable alternative in the short and medium term. In the
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