Sector imaging radar for enhanced vision

SIREV (Sec. tor Imaging Radar for Enhanced Vision) is an innovative airborne radar system which can supply high-quality images in any desired direction under almost every weather condition. In contrast to synthetic aperture radar (SAR) systems, no relative motion between sensor and targets is required, in SIREV. The high frame repetition frequency in SIREV allows to detect even very rapid changes in the imaged scenes. Besides providing a map of the earth's surface, the complex-valued radar images can be further processed to supply additional information about the topography and objects in the field of view. A fast processing algorithm has been developed for SIREN which allows a very accurate, phase preserving and efficient image formation. A prototype of a forward-looking SIREN system has been built up at the German Aerospace Center and raw data were obtained by a first demonstration flight using a helicopter as a moving platform. Motion errors of the platform could be extracted from the range compressed raw data avoiding the need of an inertial navigation system. The data processing results show good agreement with the theory. After image formation, coherent and incoherent image averaging processes have been applied to improve the image quality. The evaluation of the computational effort shows that a real-time hardware realization can be carried out using off-the-shelf digital components. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.