FINAL REPORT - Stakeholders - Ofcom

management and planning. They also support Ofcom in terms of aeronautical
requirements through bodies such as the ITU, ICAO and CEPT.
The study excluded consideration of the military frequency requirements which may have
significant impact on the primary radar utilisation status, notably in the L and S bands.
The feasibility of increased standardisation of primary radar characteristics should be
considered as a means for improving spectral efficiency and increased compatibility with
potential band sharing services. This could be carried out by industry bodies such as
EUROCAE for technical standards or by EUROCONTROL for operational standards. The
UK CAA may also be willing to consider the incorporation of more detailed spectrum
requirements in their documents such as CAP 670.
Generally the detailed technical standardisation of primary radar is not highly developed.
The self to self link nature of the system discourages technical standards which are
difficult to apply. The consensus on detailed operational requirements for primary radar
was outlined in section 3.2.3.
3.2.5 Possible Improvements to Existing Technology
3.2.5.1 Introduction
Section 3.2.2 above (Primary Radar Technology) summarises the basic primary radar
technology including some of the newer developments.
This section is aimed at summarising the main techniques available to improve the
spectrum utilisation of the current technology. The techniques described are essentially
those that are considered proven for aeronautical safety of life applications.
Primary radar transmits and receives its own signals. This has led to a situation where
radar engineers have been able to design systems to meet specific operational
requirements generally without regard to standards which are essential in a co-operative
system such as Secondary Surveillance Radar.
The consequences are that the characteristics of system vary widely and that each
system must be considered on a case by case basis. Recommendations for
improvements can only be guidelines as they may or may not apply to the specific
systems concerned.
Retrospective modifications to existing systems are generally very difficult to apply. This
is because a radar system is usually a matched system where each component is
optimised to meet the overall system performance objectives. An apparently small change
in operating parameters often results in changes to other parts of the system and can be
uneconomic. Improvements aimed at spectrum efficiency are generally more feasible for
new systems provided the features are considered at the design stage. The life
expectancy of primary radar systems is usually of the order of 15 to 20 years and this
may govern the timescales for the introduction of more spectrally efficient systems.
3.2.5.2 Efficient use of the radio spectrum by radar stations – Rec. ITU-R
M.1372-1
This Recommendation is a potential baseline for the consideration of spectral efficiency
improvements. In summary, it addresses the questions of antenna performance (including
3D systems), the use of advanced Doppler signal processing, integrators and constant
false alarm detectors. The recommendation serves to illustrate the wide range of
potential differences between radar systems with regard to spectral efficiency and
suitability for band sharing. Most of the techniques are covered in the following sections.
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