초록 ▼

An improved passive IFF system operating as a supplement to a conventional radar system including a coded variable delay system to produce like time-coded variable phase delayed identifying signal components indicative of cooperating or friendly objects and which overlap signals of other reflecting

An improved passive IFF system operating as a supplement to a conventional radar system including a coded variable delay system to produce like time-coded variable phase delayed identifying signal components indicative of cooperating or friendly objects and which overlap signals of other reflecting echo signals from the objects. The IFF system is provided with a retro-directive type antenna. The overlapping cooperating or friendly signal components and the corresponding other echo reflecting object signals are simultaneously detected at the radar system which is provided with a compensating or complementary phase delay means time coded in the same manner as the identifying IFF signal components. The identifying IFF signal components are thus produced in uniform phase and are summed up to provide a signal at the radar system whose magnitude is relatively large as compared to the combined corresponding echo reflecting signals which are in random-phase relationship. The receiver is provided with an indicator to distinguish between the inphase-identifying signal components and the random-phase corresponding echo reflector signals.

대표청구항 ▼

In a microwave energy echo object detection system having a transmitter, receiver and indicator, means on said objects responsive to microwave energy from said transmitter for producing re-radiated, time-coded, phase-delayed identifying signal components indicative of friendly objects simultaneously

In a microwave energy echo object detection system having a transmitter, receiver and indicator, means on said objects responsive to microwave energy from said transmitter for producing re-radiated, time-coded, phase-delayed identifying signal components indicative of friendly objects simultaneously with intentionally overlapping reflected echo signal components, said time-coded, phase-delayed, identifying signal components being re-radiated retro-directively in accordance with the direction of the microwave energy source, means responsive to the detected signal outputs of said receiver and time coded in the same manner as said identifying signal components whereby the re-radiated identifying signal components are maximized in comparison to said intentionally overlapping reflected echo signal components, said maximized signal having an amplitude greater than a prescribed threshold value, uncoded means responsive to the combined detected receiver output signals for producing a minimized signal below said maximized signal level, and means on said indicator responsive to said maximized and said minimized signals for distinguishing therebetween.