7754 Vol 2 Flyleaf - ICAO Public Maps

IV-C2
EUR FASID
4. For a good portion of the airspaces of the region,
present conditions of traffic density and complexity would
already justify radar services beyond those achievable
through the coverage of the existing network of primary
radar and secondary surveillance radar ground stations.
There are, however, still significant gaps in that coverage and
disparities in the currently available radar services which
reduce the continuity and thereby the effectiveness of these
services. There is thus a need for coordinated expansion and
completion of the existing radar coverage on the one hand
and for enhanced reliability and coherency of radar services
on the other.
5. The development of automated facilities for ATC,
including radar data processing and labeled air situation
displays, should allow progressive refinement of radar
services and thus contribute to improving the overall flow of
air traffic in the region. An initial aim should be to provide
the capability of continuously applying reduced longitudinal
separation (30 NM/5 min) between aircraft on a European
region-wide basis. In areas of high traffic density and where
the available technical facilities so permit, reduced
longitudinal separation down to a spacing of 20 and
eventually 10 NM should become feasible in progressive
stages.
6. A further aim should be to develop provisions under
which automatic radar transfers (handoffs) can be performed
between ATS units in an advanced state of automation. The
objective here should be to enable such transfers to be
effected systematically applying a minimum radar separation
of 5 NM and, where conditions permit, even 3 NM.
FACTORS RELEVANT TO
THE USE OF DIFFERENT
TYPES OF RADAR
7. In parts of the EUR region, the magnitude and
composition of the air traffic demanding radar services are
such that, at present, secondary and primary surveillance
radars are needed in combination so as to enable a safe and
efficient service to be provided. This combination is also
required to render the operation of non-SSR-equipped
aircraft compatible with the service to SSR-equipped aircraft
such as is true, in particular, of flight activities in the vicinity
of major aerodromes and in some parts of the lower airspace
where en-route services are needed.
8. In addition, a continuing need exists in certain areas
for using primary radar to meet national civil/military coordination
requirements. Where this is the case, a shared civil
and military use of the available primary radar facilities will
have an economical advantage, subject to technical compatibility
and operational suitability of such exploitation.
9. As SSR allows information on aircraft identity and
current altitude/flight level to be obtained in addition to a
sufficiently accurate horizontal position, its use considerably
improves radar service in terms of ATC traffic handling
capacity and flexibility. Carriage of SSR transponders with
Mode C and Mode A-4096 code capabilities will therefore
continue to be required by States of the EUR region for the
conduct of specified flight operations. Where the coverage is
not yet available over all of the airspace for which the need
of radar service has been recognized, the existing coverage
should be expanded accordingly.
10. SSR without primary radar can be used in airspace
where the nature of the traffic, availability of transponders
and applicable separation criteria allow a safe radar service
to be provided without recourse to primary radar. Adequate
legislation should be issued by the States concerned when a
separation service solely based on SSR is provided in such
airspaces. Details regarding the relevant procedures
applicable in the EUR region are contained in Doc 7030. The
use of “SSR only” should also be considered in cases where
primary radar cannot be provided on a cost-effective basis
where the operational environment allows it.
11. Certain shortcomings inherent in the performance
of SSR may affect the quality of the radar service. SSR may
be subject to garbling and degradation of transponder
performance due to known technical factors such as antenna
shielding, malfunctioning transponders, over-interrogation,
etc. The resultant inaccuracies or losses in information
availability can be overcome to a large extent by using a
multi-radar information provided by different SSR stations.
Moreover, significant improvements have resulted from the
use of advanced techniques, such as upgraded extractors and
antennas with large vertical apertures, in association with
monopulse technique. Further improvement may be
expected from enhanced monopulse systems or the eventual
availability of Mode S.
12. The development of such new radar techniques
and the enhanced capabilities of SSR systems will have a
significant impact on future radar planning. The deployment
of monopulse radars can be considered as an advantageous
intermediate step towards the extended radar services that
will become available with Mode S and its data link
possibilities. In the light of these developments, certain
primary radar stations currently used to complement en-route
services are expected to be phased out in parts of the EUR
region. It will be essential to coordinate such steps of
development on a region-wide basis and at an early stage of