Radio navigational aids

Claim 1

RADIO NAVIGATIONAL APPARATUS COMPRISING THREE RADIO TRANSMITTING STATIONS GEOGRAPHICALLY SPACED APART FOR TRANSMITTING RESPECTIVELY DISTINCT SIGNALS, RECEIVER MEANS IN A MOBILE CRAFT FOR RECEIVING THE SIGNALS TRANSMITTED BY SAID STATIONS, STABLE OSCILLATOR MEANS IN SAID CRAFT FOR PROVIDING A REFERENCE SIGNAL, PHASE DETECTOR MEANS IN SAID CRAFT CONNECTED TO SAID STABLE OSCILLATOR MEANS AND TO SAID RECEIVER MEANS FOR MAKING SEPARATE COMPARISONS OF THE PHASES OF SIGNALS DERIVED FROM THE SAID REFERENCE SIGNAL WITH THE PHASES OF SIGNALS DERIVED BY SAID RECEIVER MEANS FROM THE SIGNALS TRANSMITTED BY SAID RADIO TRANSMITTING SECTIONS TO PROVIDE THREE SEPARATE OUTPUTS RESPECTIVELY REPRESENTING THE PHASE DIFFERENCES BETWEEN THE PHASES OF SIGNALS DERIVED FROM SAID THREE RADIO TRANSMITTING STATIONS AND THE PHASES OF SIGNALS DERIVED FROM SAID REFERENCE SIGNAL, AND CONTROL MEANS COUPLED TO THE OUTPUTS OF SAID PHASE DETECTOR MEANS AND TO SAID STABLE OSCILLATOR MEANS FOR CONTROLLING SAID STABLE OSCILLATOR MEANS TO ADJUST THE PHASE OF SAID REFERENCE SIGNAL SO THAT THE OUTPUTS OF SAID PHASE DETECTOR MEANS ARE AS NEARLY AS POSSIBLE COMPATIBLE WITH THE INSTANTANEOUS POSITION OF THE MOBILE CRAFT, SAID CONTROL MEANS COMPRISING COMPUTING MEANS CONNECTED TO SAID STABLE OSCILLATOR MEANS AND TO PARAMETERS OF A TRIANGLE FORMED BY THE INTERSECTIONS OF CIRCULAR ARCS HAVING THEIR CENTERS AT THE POSITIONS OF SAID THREE RADIO TRANSMITTING STATIONS AND HAVING THEIR RADII CALCULATED FROM THE OUTPUTS OF SAID PHASE DETECTOR MEANS TO PROVIDE AN OUTPUT DERIVED FROM THE SAID PARAMETERS FOR CONTROLLING SAID STABLE OSCILLATOR MEANS TO REDUCE THE IN-RADIUS OF SAID TRIANGLE TOWARD ZERO.