JPS6431073A - Guiding equipment - Google Patents

Abstract

PURPOSE:To make it possible to guide a missile accurately, by enabling a filter circuit for removing background noises when a target is remote, and disabling the filter circuit when the target approaches. CONSTITUTION:A power operation circuit 24 receives the output of an infrared photodetector 3 and performs high speed Fourier transformation 23. Power, in which a frequency band wherein background noises are present is normalized, is obtained. Then a judging circuit 25 makes a switching signal 26 significant when the power is smaller than a predetermined threshold value. A multiplexer 27 supplies a first analog video signal to an A/D converter 7, at a time when the switching signal 26 becomes significant. Thus, a filter circuit 5 becomes effective when a detected target is small and the background noises are dominant. The background noises are removed, and the video signal undergoes binary coding. After the detected target becomes large and the background noises are decreased, the deformation of the target signal is prevented. The signal, which does not pass the circuit 5, undergoes binary coding, and a missile can be guide accurately.