Device for discriminating between multiple targets for an infra-red homing head

摘要

A device for discriminating between multiple targets for an infra-red homing head. The device uses a modulation grid (1) on which the image of a target is focused and which comprises a modulating sector (2) and a complementary opaque portion. The modulating sector (2) is divided into p concentric zones (22) consisting of alternate opaque (4) and transparent (5) parts in numbers characteristic of the concentric zone in question. The signal from the modulation grid has a fundamental frequency characteristic of the concentric zone belonging to the target. After this infra-red signal has been converted into an electrical signal by a detection cell, the electric signal is vectorially demodulated from a demodulation base consisting of 2p direct signals in quadrature with the p fundamental frequencies. The signals from this demodulation are then integrated over the time taken to pass over a sector and are summed in pairs. An analysis of the p signals obtained enables the presence of one or more targets to be detected. The device can discriminate both by radial position and between sectors. The final information can be used to create the commands required to track a target. IMAGE