FINAL REPORT - Stakeholders - Ofcom

conditions, the effect of sporadic interference on probability of detection can be very
small.
The paper is a preliminary view only and recommends that the introduction of a statistical
and operational aspects in the protection criteria should be further studied by WP 8B. This
view is supported by the study team noting the following points:-
• The assumptions used in the paper do not apply to all radar systems. In
particular, the retention on the controller’s display of a “coasting” radar plot for up
to four consecutive lost plots (an aircraft travels a long way in four rotations of
the antenna) is not acceptable in many operational environments. For example,
aircraft manoeuvring in the approach environment or military aircraft pulling high
G turns.
• The major issue is one of whether the safety case can be demonstrated in an
interference environment. The ATC industry uses safety methodologies which
are more related to those used in the nuclear industry in terms of safety
requirements.
• It is difficult to provide a generalised approach to statistical analysis in an
environment where the radar characteristics and operational requirements vary
significantly from one system to another.
• The scope of the statistical study must be representative of current and future
radar systems and their operational requirements. This will require an input from
the specialists in the field.
3.2.5.15 Improvements to Technology – Summary
Improvements to the technology can be considered in three categories:
1. Minor improvements to existing systems such as the incorporation of filters in
magnetron systems which may provide limited benefits in specific circumstances.
2. Improvements which are likely to be inherent in the design of new radar systems and
provide more optimum spectrum utilization benefits. They include the adoption of
design aim emission mask standards, controlled pulse shaping, pulse compression
and solid state transmitters.
3. More fundamental changes which are likely to give spectrum utilisation benefits.
These include:
• More studies of band sharing techniques involving, for example, statistical
methods.
• Advanced radar techniques, for example, bistatic or CW radar.
• The use of electronically steered beam antenna technology.
These techniques are characterised by the need for significant R&D and will take
many years to implement.
3.2.6 Replacement Technologies (In Band and Other)
Primary radar is a unique technology in the sense that it requires no co–operation from
the target under surveillance. There are no issues of fleet fit and as long as there is a
requirement for an independent non co-operative facility of this nature then there are
currently no alternative technologies.
However, it should be noted that SSR is the main operational tool in controlled airspace
and in many ways is the “replacement technology” for primary radar. The availability of
SSR has minimised the demand for primary radar although not to the point where the
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