Localization, from the observed far-field, of radiating centers in a 3D-scene

It is well known that characteristics of an antenna can be very different when it is mounted on a platform. Indeed, a part of the emitted field is diffracted by the structure and interferes with the direct component and the theoretical radiation pattern is then modified. The knowledge of alterations caused by platform on antenna characteristics is important in order to reduce such effects. In high-frequency domain, the platform can be modelized as a collection of coherently point scatterers illuminated in near-field by the antenna: the structure is modelized as a collection of “radiating centers”. Ozdemir et al. [1][2] have investigated this problem by proposing a method of imaging, the antenna synthetic aperture radar (ASAR) solution. This method permits to locate the dominant secondary radiation off the platform by collecting multifrequency and multiaspect radiation data from an antenna mounted on a platform under the small-angle approximation and single bounce assumption. In this paper, the authors propose another method which is an extension to the 3D-case of the solution presented in [3]. This new approach is also achieved under the single bounce assumption but for a constant frequency and under multiaspect radiation data with an observed far field over 2pi steradians. After presenting the antenna/radiating centers set modelization, a method to extract radiating centers consisting in a substitution with estimated angles and calculation of a 2D-FFT is proposed. Results obtained with this method on a scene which contains a set of punctual radiating centers are presented..