Abstract: An imaging system is provided where radiation from object space (2) is incident on an array of detector elements (8) via an interferometer (3), the interferometer (3) Being scanned such that the output of each pixel comprises an interferogram B generated from the radiation received from a corresponding region of object space (2), enabling image data to be generated in dependence on the output of the pixels, which image data is derived from the spectral radiance associated with each pixel.

Abstract: A method and apparatus are provided for determining whether a signal received the main channel (2) of an antenna (1) was incident on the antenna (1) in a direction corresponding to a high gain main lobe. A sidelobe suppression signal is generated from signals received from a other channels at least some of which are derived from elements where output generates the main channel, the signal being categorized as originating from a direction corresponding to the high gain main lobe of the main channel by comparing the value of the signal received on the main channel with that of sidelobe suppression signal.