FINAL REPORT - Stakeholders - Ofcom

• To maintain or improve the orderly and efficient flow of traffic.
These constraints mean that the route taken by civil aircraft is often not the fastest or
most efficient one. Strenuous efforts are made in today’s environment to ensure that
aircraft are in the air for the least time possible; passengers benefit from shorter flights
and airlines (and the environment) benefit with less fuel being burnt.
Unique constraints are also in place near airports; i.e. within the TMA. Aircraft must be
able to line up with the runway from several miles away. The controller must sequence
and merge aircraft arriving on several different routes onto one approach path. As the
aircraft comes near the ground, noise and environment constraints must be taken into
account.
As the traffic grows, the constraints must become tighter – i.e. navigational performance
must increase. It has moved from 2D to 3D, and is likely to move to 4D (i.e. with time) in
the near future. Accuracy of navigation is continually increasing, and the availability of
navigation aids (or GNSS) will also grow in the future.
3.4.2 Frequency Allocations
3.4.2.1 Scope
This section illustrates the current frequency usage profile for navigation systems in the
United Kingdom of Great Britain and Northern Ireland, the State of Jersey and Eire.
3.4.2.2 Loran-C
The band 90-110 kHz is allocated for RNS usage (and particularly in Europe and the US
for Loran-C). 1800-2000 kHz is allocated to the now-defunct LORAN-A, and is currently
used primarily for amateur applications.
Internationally, the allocation to Loran-C is driven by the USA (and likely to continue to be
– maritime use by the US Coast Guard service). Europe is represented by the Northwest
European Loran-C System (NELS), which includes UK coverage.
3.4.2.3 NDB
Internationally, 130-535 kHz is allocated for aeronautical radionavigation services. Within
ICAO’s Region 1 (Europe), 255-526.5 kHz is allocated to NDBs, although maritime uses
some of this band. 7 It is bounded by the LF and MF sound broadcasting bands.
Note also that mobile aeronautical NDBs, which are mainly military, operate in the UK up
to 979 kHz, along with MF broadcasting.
3.4.2.4 Marker Beacons
Short range radionavigation beacons are centred on 75 MHz (74.8-75.2 MHz). Power
output is typically 3W or less.
7 Note that the mobile detection equipment – Automatic Direction Finders – are able to
receive signals in the range of 190-1800 kHz.
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