ABSTRACT
In the last few decades, microwave-and millimeter-wave radars, active and passive (the latter are usually called in the literature radiometers, see [1-12]) have become important technical facilities in various remote sensing applications of the earth’s environment, such as ground subsoil medium, atmosphere, and ocean. Radiometers of this kind were developed from the mid-1980s to the early 1990s simultaneously in the former USSR, the United States, and Europe [12-19]. Recently, several kinds of passive millimeter-wave (MMW) radiometers have been developed and reported in [20-24]. They are capable of imaging during poor weather conditions and nocturnal time periods. Moreover, passive radar is undetectable and is not degraded by path error or speckle noise. Essentially, detecting various thermic emissions from the target under searching MMWradar provides additional information about its peculiarities compared with that obtained by lowfrequency radars or optical and infrared (IR) detectors, for more accurate estimation of the target “response.”
