FINAL REPORT - Stakeholders - Ofcom

1.2.1.2 Secondary radar
The key developments which influence use of the 1030/1090 MHz frequencies are:
• The transfer to Mode S from current SSR. As well as a number of operational
benefits, this provides a reduction in the level of interference and makes it
possible to maintain SSR services as traffic grows.
• The implementation of ADS-B services via 1090 extended squitter, which whilst
offering potential operational benefits, will increase the use of the 1090 MHz
spectrum and possibly saturate.
Recommendations 3.15 to 3.17 below apply to the efficient use by SSR of the 1030/1090
MHz frequencies
Recommendation 3.15: Ofcom should satisfy themselves that the CAA has taken the
appropriate steps to ensure that the tailoring of SSR Pulse Repetition Frequencies
conforms to ICAO recommendations.
Recommendation 3.16: The implementation of Mode S SSR in the UK should be
encouraged (allowing selective addressing and potentially fewer replies) coupled with the
implementation of measures to encourage equipage and the appropriate implementation
of controller tools which use the resulting data.
Recommendation 3.17: Mode S Extended Squitter implementation – Ofcom should work
with the CAA in ensuring that data downlinked from the aircraft is not superfluous to
requirements. In particular this means reviewing the need for the regular broadcast of
DAPs.
The next two recommendations apply to the introduction of new services on the 1090
MHz frequency.
Recommendation 3.18: The 1090MHz channel will be severely constrained in the
medium term. A review of the future use of this band should be carried out. The review
should ensure that any new applications meet clearly defined operational requirements; if
not, studies should be performed to assess the potential benefit against the cost to an
already saturated channel. The studies should also assess the timescales over which the
applications will remain effective given that increased traffic will further saturate the
channel. Crucially, it should be ensured that the introduction of new applications does not
impact on existing safety of life applications such as SSR and ACAS.
Recommendation 3.19: Ofcom should work with the CAA to evaluate other technologies
for ADS-B and ensure that spectrum efficient solutions are developed and implemented.
The final recommendation applies to extension of the use of the 1030 MHz frequency.
Recommendation 3.20: The possibility of further utilising 1030MHz (for example, for TIS-
B) should be encouraged and studied.
1.2.1.3 Aeronautical Radio-Navigation Services
Recommendation 3.21: Ofcom should work with the CAA to ensure the timely
decommissioning of non-operationally required radio navigation aids, in particular, NDBs
and VORs. The following caveats apply:
• The requirements of General Aviation and the Military for NDBs and VORs in the
UK must be urgently addressed;
• The impact of an RNAV only environment should be assessed, particularly from
a safety and security viewpoint.
Page 14