Attitude-sensing device

Claim 1

ELECTRONIC APPARATUS FOR CONTINOUSLY DETERMINGING THE DIRECTION OF ONE OF THE FIELD VECTORS, MAGNETIC OR ELECTRIC, OF AN INTERCEPTED SIGNAL, SAID APPARATUS COMPRISING: THREE ANTENNAS RESPECTIVELY POSITIONED AND ORIENTED ALONG THE AXES OF A THREE-DIMENSIONAL ORTHOGONAL SYSTEM OF REFERENCE FOR PRODUCING AXIAL COMPONENTS OF THE INTERCEPTED SIGNAL, SAID ANTENNAS BEING SMALL COMPARED TO THE WAVELENGTH OF THE INTERCEPTED SIGNAL AND POSITIONED CLOSE TO THE ORIGIN OF THE REFERENCE SYSTEM; AND MEANS COUPLED TO SAID THREE ANTENNAS FOR RECEIVING SAID AXIAL SIGNAL COMPONENTS, SAID MEANS USING SAID SIGNAL COMPONENTS TO PRODUCE OUTPUT SIGNALS WHOSE MAGNITUDES RESPECTIVELY CORRESPOND TO THE ANGLES FORMED BETWEEN A FIELD VECTOR OF THE INTERCEPTED SIGNAL AND THE AXES OF SAID REFERENCE SYSTEM, SAID LAST MEANS COMPRISING A 90* PHASE SHIFTER, MEANS FOR LINEARLY SUMMING ONE OF THE AXIAL COMPONENTS OF A FIELD VECTOR WITH A SECOND AXIAL COMPONENT AFTER PASSAGE OF ONE OF SAID AXIAL COMPONENTS THROUGH SAID PHASE SHIFTER, MEANS FOR PHASE COMPARING THE OUTPUT OF SAID SUMMING MEANS WITH ONE OF SAID AXIAL COMPONENTS TO PRODUCE ONE OF SAID OUTPUT SIGNALS, A REFERENCE FREQUENCY SOURCE, FIRST AND SECOND PHASE-LOCK LOOP CIRCUIT MEANS; MEANS FOR INTRODUCING THE REFERENCE FREQUENCY INTO SAID FIRST AND SECOND PHASE-LOCK LOOP CIRCUIT MEANS 90* OUT OF PHASE, MEANS INTRODUCING THE THIRD AXIAL VECTOR COMPONENT INTO ONE OF SAID PHASE-LOCK LOOP CIRCUIT MEANS TO PRODUCE A FIRST INTERMEDIATE FREQUENCY SIGNAL IN FIXED FREQUENCY AND PHASE RELATIONSHIP WITH SAID REFERENCE FREQUENCY, MEANS INTRODUCING THE FIRST AND SECOND AXIAL COMPONENT OUTPUT OF SAID SUMMING MEANS INTO THE OTHER OF SAID PHASE-LOCK LOOP CIRCUIT MEANS TO PRODUCE A SECOND INTERMEDIATE FREQUENCY SIGNAL IN FIXED FREQUENCY AND 90* PHASE SHIFTED RELATIONSHIP WITH THE REFERENCE, MEANS FOR LINEARLY SUMMING THE FIRST AND SECOND INTERMEDIATE FREQUENCY OUTPUT OF SAID FIRST AND SECOND PHASE-LOCK LOOP MEANS, AND MEANS FOR PHASE COMPARING THE OUTPUT OF SAID LAST LINEAR SUMMING MEANS WITH SAID REFERENCE FREQUENCY TO PRODUCE A SECOND OUTPUT SIGNAL.