Signal detection system

Claim 1

IN A SYSTEM FOR DETERMINING THE POSITION OF A MOVING TARGET WHEREIN FIRST AND SECOND VERSIONS OF A SIGNAL TRANSMITTED FROM SAID TARGET ARE RECEIVED AT A GIVEN STATION AND TRANSDUCED TO TWO SIGNAL VERSIONS, THE COMPONENTS OF WHICH ARE RELATED BY A PREDETERMINED DIFFERENCE FREQUENCY WHICH VARIES WITHIN A FIRST GIVEN BAND OF FREQUENCIES DUE TO DOPPLER FREQUENCY SHIFT BROUGHT ABOUT BY SAID MOVING TARGET, AND WHICH TWO SIGNAL VERSIONS ARE SUPERIMPOSED ON RANDOM NOISE ENERGY, THE COMBINATION OF MEANS FOR CORRELATING SAID TWO SIGNAL VERSIONS AND INCLUDING MEANS CONNECTED TO MULTIPLY SAID TWO SIGNAL VERSIONS TO PRODUCE A RESULTANT INFORMATION SIGNAL THE SIGNAL FREQUENCIES OF WHICH FALL WITHIN SAID FIRST GIVEN BAND, SAID RESULTANT INFORMATION SIGNAL BEING SUPERIMPOSED ON RANDOM NOISE ENERGY DEFINED BY A RELATIVELY WIDE SECOND BAND OF FREQUENCIES EMBRACING SAID FIRST GIVEN BAND, MEANS CONNECTED TO DEVELOP A FIRST INDICATING SIGNAL REPRESENTING THE POWER CONTENT OF A THIRD BAND OF SIGNAL FREQUENCIES FALLING WITHIN SAID SECOND BAND AND SUBSTANTIALLY EXCLUSIVE OF SAID FIRST BAND, MEANS CONNECTED TO DEVELOP A SECOND INDICATING SIGNAL REPRESENTING THE POWER CONTENT OF A FOURTH BAND OF SIGNAL FREQUENCIES FALLING WITHIN SAID SECOND BAND AND INCLUDING SAID FIRST BAND, AND MEANS CONNECTED TO COMBINE SAID FIRST AND SECOND INDICATING SIGNALS TO PRODUCE A RESULTANT INDICATING SIGNAL WHICH REPRESENTS SUBSTANTIALLY ONLY SAID RESULTANT INFORMATION SIGNAL.