Millimeter wave length guidance system

A high frequency target seeking device, using a stabilised reflector antenna (20), performs range search and tracking functions and target angle search and tracking functions. A technique is provided for target range discrimination using several narrow band i.f. filters (8l), also thereby improving signal-to-clutter ratio and signal-to-receiver noise ratio. Target search is accomplished with simultaneous range and antenna azimuth scanning, with the range bins (82) and the antenna beam swept across the target. A multiplexer (83) selects the range bin (82) having signals indicative of the target. Target range tracking is accomplished by the mutliplexer (83) additionally automatically selecting range bins adjacent the range bin of the target and comparing their output signals. Antenna stabilisation is accomplished utilising signals from vehicle pitch, roll, and yaw rate sensors, and antenna elevation and azimuth rate and angle sensors (60-68). These signals are processed in the antenna control circuit according to predetermined relationships to provide the desired antenna stabilisation.