An imaging apparatus 6 has means for illuminating a selected surface with a radar beam footprint, and means for profiling/processing the resultant radar returns in an efficient and logical fashion such as to derive radar attitude information in real time about a number of predefined axes associated with the radar which depends upon the relative dispositions of the radar and the selected surface and upon the radar beam footprint characteristics. Advantageously, a plurality of transmit beams 10,11,12 are used to image the surface and the processing arrangement has the capability of determining roll, pitch and/or yaw pointing data associated with the radar, such pointing data being determined by derivation of the attitude information and by selective input of terrain elevation data so as to take account of variations in the radar viewing geometry with terrain elevation. The inventive radar bears a definite low cost advantage over known radar designs, and retains utility for many applications, for example spaceborne and airborne applications.