Systems for determining the elevation angle and azimuth of a body

Claim 1

A RECEIVER FOR RECEIVING, DURING TIME INTERVALS OCCURRING WITH A SUBSTANTIALLY CONSTANT REPETITION FREQUENCY, A CARRIER WAVE WHICH IS AMPLITUDE MODULATED BY A FREQUENCY MODULATED WAVE AND TRANSMITTED AS A MOVING BEAM THE RECEPTION LEVEL OF SAID CARRIER WAVE BEING MODULATED IN THE COURSE OF EACH OF SAID TIME INTERVALS BY THE LOTION OF THE BEAM AND BEING MAXIMUM AT THE INTERMEDIATE INSTANT OF SAID TIME INTERVALS, SAID RECEIVER COMPRISING: MEANS FOR RECEIVING SAID CARRIER-WAVE; MEANS FOR DEMODULATING SAID CARRIER WAVE TO OBTAIN A FREQUENCY MODULATED SIGNAL CONSTITUDED BY SAID FREQUENCY MODULATED WAVE, ADDITIONALLY AMPLITUDE MODULATED BY SAID MOTION OF SAID BEAM; AUTOMATIC GAIN CONTROL MEANS FOR MAINTAINING SUBSTANTIALLY CONSTANT THE MAXIMUM AMPLITUDE OF SAID FREQUENCY MODULATED SIGNAL FOR EACH OF SAID TIME INTERVALS; MEANSA FOR AMPLITUDE DETECTING SAID FREQUENCY MODULATED SIGNAL; MEANS FOR DERIVING FROM SAID AMPLITUDE DETECTED SIGNAL A GATING SIGNAL, THE DURATION OF WHICH CORRESPONDS TO THE INTERVAL OF TIME DURING WHICH SAID AMPLITUDE DETECTED SIGNAL IS ABOVE A PREDETERMINED LEVEL; A NORMALLY BLOCKED OSCILLATION SOURCE HAVING THE SAME FREQUENCY VARIATION RANGE AS THE POSSIBLE VARIOUS INSTANTEOUNS FREQUENCIES OF SAID FREQUENCY MODULATED WAVE; A NORMALLY BLOCKED LOW FREQUENCY AMPLIFIER; MEANS FOR APPLING SAID FREQUENCY MODULATED SIGNAL TO SAID LOW FREQUENCY AMPLIFIER; MEANS FOR APPLYING SAID GATING SIGNAL TO SAID LOW FREQUENCU AMPLIFIER AND TO SAID SOURCE TO UNBLOCK THEN DURING THE DURATION OF SAID GATING SIGNAL; MEANS FOR DERIVING FROM THE OUTPUT SIGNAL OF SAID LOW FREQUENCY AMPLIFIER A FIRST SERIES OF PULSES WHOSE NUMBER IS A PREDETERMINED FUNCTION OF THE NUMBER OF CYCLES CONTAINED IN SAID OUTPUT SIGNAL OF SAID LOW FREQUENCU AMPLIFIER; MEANS FOR DERIVING FROM THE OUTPUT SIGNAL OF SAID OSCILLATOR SOURCE A SECOND SERIES OF PULSE WHOSE NUMBER IS SAID PREDETERMINED FUNCTION OF THE NUMBER OF CYCLES CONTAINED IN THE OUTPUT SIGNAL OF SAID SOURCE AN INTEGRATING AND SUBTRACTING DEVICE HAVING TWO INPUTS AND AN OUTPUT, FORMING THE DIFFERENCE BETWEEN THE INTEGRATED QUANTITIES OF ELECTRICITY RESPECTIVELY APPLIED TO ITS TWO INPUTS; AND MEANS FOR APPLYING SAID FIRST AND SECOND PULSED SIGNALS RESPECTIVELY TO SAID TWO INPUTS TO OBTAIN ON SAID OUTPUT AN ERROR SIGNAL BETWEEN THE CENTRAL INSTANTANEOUS FREQUENCY OF THE OUTPUT SIGNAL OF SAID LOW AMPLIFIER AND THE OPERATING FREQUENCY OF SAID OSCILLATION SOURCE.