Passive Millimeterwave Imaging at short and medium Range

摘要

During recent year's research on radiometric signatures, non-imaging, of the exhaust jet of missiles and imaging, on small vehicles in critical background scenarios were conducted by the mmW/submmW-group at FGAN-FHR. The equipment used for these investigations was of low technological status using simple single channel radiometers on a scanning pedestal. Meanwhile components of improved performance are available on a cooperative basis with the Institute for Applied Solid State Physics (Fraunhofer-IAF). Using such components a considerable progress concerning the temperature resolution and image generation time could be achieved. Emphasis has been put on the development of a demonstrator for CWD applications and on an imaging system for medium range applications, up to 200 m. The short range demonstrator is a scanning system operating alternatively at 35 GHz or 94 GHz to detect hidden materials as explosives, guns, knifes beneath the clothing. The demonstrator uses a focal plane array approach using 4 channels in azimuth, while mechanical scanning is used for the elevation. The medium range demonstrator currently employs a single channel radiometer on a pedestal for elevation over azimuth scanning. To improve the image quality, methods have been implemented using a Lorentzian algorithm with Wiener filtering.