1 INTRODUCTION1.1 Radar reflectors carried under SOLAS
chapters V and X should comply with the minimum performance requirements as specified
in this Recommendation.
1.2 In the
following paragraphs, radar cross sections
1 are specified for the
frequencies of 3 GHz (S-band) and 9 GHz (X-band) whose wavelengths are 10 cm and 3 cm
respectively.
1.3 The performance
requirements stated should apply to either active or passive radar reflectors in both
9 GHz and 3 GHz bands. (Active radar reflectors are also known as radar target
enhancers).
2 APPLICATION2.1 All ships required to be fitted with a
radar reflector, if practicable, to enable detection by ships navigating by radar at
both 9 GHz and 3 GHz bands.
3 PERFORMANCE3.1 The radar reflector should have a
.Stated Performance Level. measured in square metres radar cross section (m2 RCS) of
at least 7.5 m
2 in X-band and 0.5 m
2 in S-band mounted at a
minimum height of 4 m above water level.
3.2 Required minimum level for reflector performance - the Stated
Performance Level should:
- be maintained over a total of at least 280° azimuth;
- not remain below this level over any single angle of more than 10° - a
null; and
- not have distances between nulls of less than 20°.
3.3 For power driven vessels and sailing vessels designed to operate with
little heel (catamaran/trimaran), this performance should be maintained through angles
of (athwartships) heel 10° either side of vertical. For other sailing vessels, the
reflector should maintain this performance over 20° either side of vertical.
3.4 Active reflectors should conform to Recommendation ITU-R M.1176.
4 CONSTRUCTION4.1 The reflector should be capable of
maintaining its reflection performance under the conditions of sea states, vibration,
humidity and change of temperature likely to be experienced in the marine environment
as defined by resolution A.694(17)
2.
5 INSTALLATION5.1 Fixing arrangements should be provided
so that the reflector can be fitted either on a rigid mount or suspended in the
rigging.
5.2 The recommended mounting
height of 4 m and any preferred orientation should be permanently and clearly marked
on the reflector.
5.3 The reflector should
be clearly and permanently marked if it will meet the performance requirement to ± 20°
inclination (heel).
5.4 For small-craft,
the maximum weight for mounting at 4 m should be 5 kg. Reflectors designed for
mounting at a greater height should be of weight calculated as equivalent to, or less
than 4 m/5 kg. Physical sizes should be minimised and should not exceed 0.05
m
3.
1 The Radar Cross Section is a measure of the ability of an object to
return microwave energy to the interrogating radar when compared to the actual
reflectivity of a metal sphere.
2 IEC Publication 60945.