Joint French-German radar measurements for the determination of the refractive index in the maritime boundary layer

To predict the performance of coastal and shipborne radars, it is essential to assess the propagation characteristics of electromagnetic waves in the maritime boundary layer. To be independent upon environmental measurements, which are generally not as precise and reliable as they have to be for a proper input to simulation programs, usually based upon parabolic equation models, a method to retrieve the refractive index gradients in the low troposphere is the Refractivity from Clutter (RFC) algorithm. The propagation factor is computed from the received clutter power and is iteratively processed in order to retrieve the refractive index profiles. Under a respective French-German technical agreement a measurement program concerning radar propagation in the maritime boundary layer has been initiated, with contributions from ONERA-CERT, DGA MI/TN, Fraunhofer-FHR and the German Technical Center for Ships and Naval Weapons (WTD 71). The paper gives an overview on the RFC met hod with examples from the previous campaigns. It describes the experimental set-up and its methodology.