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the normal requirement for 360 degree coverage and the wide range of users for a given
radar service, it usually proves difficult to blank a specific sector.
3.2.3.9 Primary Radar Operational Requirement Summary
The position on the operational requirement for primary radar services can be
summarised as follows:
• In the UK, there is likely to be a continuing requirement for primary radar for en
route, approach/TMA and airport surface movement applications.
• The scope of operational requirements is likely to remain static although there
may be a requirement for reduced false alarm rates.
• The requirement for security based requirements is likely to increase.
• The number of radar facilities supporting approach and surface movement
requirements is likely to grow in line with the general expansion in air transport.
• The requirement for long range primary radars is likely to remain constant with
security issues a potential additional driver.
Hence, there appears to be little scope for reduced spectrum requirements based on a
relaxation of operational requirements.
3.2.4 Regulatory and Standardisation Issues
3.2.4.1 UK CAA
The CAA (DAP) support the aviation line that dedicated spectrum for aviation is the
correct approach but recognise that the case must be appropriately justified to ITU.
The UK CAA Safety Regulation Group produces a number of policy, guidance and
requirements documents which cover primary radar as follows:
Air Traffic Services Operation Memorandum (ATSOM) No 39 (Issued to Service Providers
in December 2000). The key statements from this document are: ‘PSR is the minimum
level of equipment necessary to support any form of Radar Control, Radar Advisory or
Radar Information Service. SSR may supplement the PSR to safely accommodate
increases in traffic complexity or density. In the En-Route environment, PSR must be
provided in areas of high density or high complexity. In areas of light traffic, but
nevertheless requiring a surveillance service, standalone SSR may be sufficient. PSR is
required wherever the Controlling Authority of the airspace concerned has a need to
provide radar separation between transponding and non-transponding traffic.’
Air Traffic Information Services Notices (ATSIN) No 30. Issued to Service Providers in
May 2003, reminds them of the continuing validity of ATSOM 39, and provides additional
information concerning any changes to existing radar systems. ATSIN 35 extends the
lifetime of ATSIN 30.
Safety Requirements for the provision of Radar Services are contained in CAP670 Part C,
Section 3, Surveillance. The material contained in this document sets out the
requirements to be met by providers of civil air traffic services and associated services in
the UK in order to ensure that those services are safe for use by aircraft and meet
internationally agreed standards. Inherent in this process is the need to have control over
the operating environment. In addition to requirements, the text offers explanatory notes
and guidance material on acceptable methods of compliance with the requirements. This
paper makes reference to spurious frequency components for primary radar and specifies
a level of – 50 dB for spurious components relative to the mean power.
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