FINAL REPORT - Stakeholders - Ofcom

3.4.7.7 L-Band DME
Internationally, the implementation of UAT (Universal Access Transceiver) for ADS-B will
impact upon a narrow range of frequencies in-band (thought to be around 966MHz or
978MHz). Initially, this will affect the USA, but the requirement for global harmonisation
may see this frequency allocated in Europe in the medium term.
The MoD uses some of the spectrum for aeronautical communications, following
agreements with DAP (for non-interference with the primary use of ARNS).
3.4.7.8 L-Band GNSS
The introduction and proliferation of Ultra-Wide Band (UWB) solutions has caused
concern amongst the aviation fraternity, in part because UWB has been unregulated in
the past. UWB is a low-power, high bandwidth communications method, with bandwidths
spread over more than 1.5MHz.
The effects of UWB can be negated by technical solutions – examples include frequency
hopping or pulsing, thus avoiding the RNSS and ARNS allocated frequencies. However,
problems still exist with the aggregate effect that thousands of mobile wireless unlicensed
UWB devices might have on the overall noise floor. The USA has detected the problem
(as described in a recent IATA paper), and points out that spectrum protection is not
conducted by the airlines, but by government or international bodies. UWB spectrum is
part of private spectrum that is overseen in the US by the Federal Communications
Commission, which has a remit of allowing maximum access for the most users. As such,
UWB is currently being promulgated through safety-of-life service frequency allocations
(in particular, from 1559 to 1626.5MHz).
3.4.8 Replacement Technologies (radio, other or none)
3.4.8.1 Loran-C
As the planned EGNOS technology comes on-line, there will be strong pressure for users
to move to the new augmentation system (in time for the introduction of Galileo, Europe’s
GNSS) – particularly if the safety case for EGNOS proves favourable for safety critical
applications.
3.4.8.2 NDB
GNSS is likely to replace the requirement for NDBs, particularly as Galileo comes on-line
circa 2008.
The take-up of GNSS amongst GA users depends primarily on the availability of low-cost
solutions.
3.4.8.3 Marker Beacons
Marker beacons are being replaced by DME systems (co-located with the ILS).
3.4.8.4 ILS
ILS may be replaced by MLS (Microwave Landing System), where the commercial and
safety aspects are beneficial. MLS allows for greater accuracy, and negates the multipath
effects experienced by ILS (off buildings, aircraft etc).
In time, GNSS Landing Systems (GLS) may become standard – at present, they are able
to support Category I approaches (work is on-going for Cat II and III).
There is pressure on the glideslope allocation from other aeronautical mobile services.
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