Target sensing and homing system

A radar target sensing and homing device comprising:

• an antenna and transmitter for transmitting a broad fan beam containing a plurality of closely spaced interference lobes said lobes being spaced so as to encompass a predetermined target size,
• a receiver and said antenna for receiving echo signals from targets present in said interference lobes,
• means interconnected between said transmitter and receiver for preventing transmitted signals from entering said receiver during transmitting periods and for permitting reception of said echo signals in said receiver means during receiving periods,
• means for continuously varying the position of said interference lobes,
• said antenna and said position varying means determining the ratio of the target to the beam area whereby the detection of false targets is reduced,
• means responsive to said antenna for developing sum and difference signals,
• a first mixer stage in said receiver for receiving the sum output signal,
• a second mixer stage in said receiver for receiving the difference output signal,
• a local oscillator in said receiver providing outputs to said first and second mixer stages for generation of sum and difference intermediate frequency signals,
• a phase sensitive detector in said receiver, and first and second IF amplifiers in said receiver for amplifying said sum and difference signals respectively as inputs to said phase sensitive detector said phase detector measuring the ratio of the sum and difference signals to provide an output signal which represents the angle to the target.

In a target sensing device a sensor means comprising:

• first and second interconnected slotted waveguide antenna means for generating a broad fan beam and a plurality of closely spaced interference lobes contained within said broad fan beam said interference lobes spaced so as to encompass a predetermined target size at a predetermined range,
• a phase shifter for continuously varying the positions of said interference lobes within said broad fan beam,
• means for detecting said predetermined size target within said interference lobes, and
• means combined with said means for detecting for filtering out undesired targets.

In a target sensing device a sensor means comprising:

• means for generating a broad fan beam containing a plurality of closely spaced interference lobes said interference lobes spaced so as to encompass a predetermined target size, said generating means also receiving target returns,
• means for continuously varying the position of said interference lobes within said broad beam,
• means for developing sum and difference signals from said received signals,
• a first mixer stage for receiving the sum output signal,
• a second mixer stage for receiving the difference output signal,
• a local oscillator providing outputs to said first and second mixer stages for generation of sum and difference intermediate frequency signals,
• a phase sensitive detector, and
• first IF and second IF amplifiers for amplifying said sum and difference signals respectively as inputs to said phase sensitive detector said phase detector measuring the ratio of the sum and difference signals to provide an output signal which represents the angle away from the ground track to the target.