Validation of vertical refractivity profiles as required for performance prediction of coastal surveillance radars

Maritime border safeguarding is a vital component in the protection of a countries resources and interests against illegal activities. With the increasing asymmetric nature of today´s threats, a primary requirement of any coastal surveillance system is the ability to detect small targets, such as rigid inflated boats and skiffs. The main contribution towards the radar cross section for these small targets is typically the engine and the human operator, which are approximately 1 m above the sea surface. When illuminated by a radar system, such targets are typically covered by the lowest lobes of the radar´s pattern propagation factor. The behavior of these lobes is significantly influenced by the refractivity profile of the atmosphere. This paper presents the simulation of vertical refractivity profiles for modeling the detection performance of coastal surveillance radars. Validation is provided through meteorological and radio wave propagation measurements undertaken in False Bay, South Africa.