Apparatus for providing lane identifi, cation in hyperbolic position finding systems

Claim 1

IN A TRANSMITTING SYSTEM FOR USE IN A TWO FOCI HYPERBOLIC, CONTINUOUS WAVE, LOCATION SYSTEM, FIRST AND SECOND FIXED TRANSMITTING STATIONS EACH CONTINUOUSLY RADIATING A POSITION INDICATING SIGNAL WITH SID POSITION INDICATING SIGNALS DIFFERING FROM EACH OTHER IN FREQUENCY BUT FALLING WITHIN A FIRST FREQUENCY CHANNEL, MEANS AT EACH OF SAID FIXED STATIONS FOR RADIATING FIRST AND SECOND AMBIGUITY RESOLUTION SIGNALS ALTERNATELY WITH EACH OTHER, THE FIRST AMBIGUITY RESOLUTION SIGNALS RADIATED FROM THE TWO FIXED STATIONS DIFFERING FROM EACH OTHER IN FREQUENCY BUT FALLING WITHIN A SECOND FREQUENCY CHANNEL, THE SECOND AMBIGUITY RESOLUTION SIGNALS RADIATED FROM THE TWO FIXED STATIONS ALSO DIFFERING FROM EACH OTHER IN FREQUENCY BUT FALLING WITHIN A THIRD FREQUENCY CHANNEL, THE AMBIGUITY RESOLUTION SIGNALS OF THE SECOND CHANNEL BEING RADIATED SIMULTANEOUSLY FROM SAID FIRST AND SECOND STATIONS DURING A FIRST INTERVAL AND THE AMBIGUITY RESOLUTION SIGNALS OF THE THIRD CHANNEL ALSO BEING RADIATED SIMULTANEOUSLY FROM THE FIRST AND SECOND STATIONS DURING A SECOND INTERVAL, THE FREQUENCY DIFFERENCE BETWEEN THE TWO AMBIGUITY RESOLUTION SIGNALS OF THE SECOND CHANNEL BEING EQUAL TO THAT BETWEEN THE TWO AMBIGUITY RESOLUTION SIGNALS OF THE THIRD CHANNEL, A REFERENCE TRANSMITTING STATION FOR RADIATING ADDITIONAL SIGNALS, FIRST RECEIVING MENAS AT THE REFERENCE STATION FOR RECEIVING THE POSITON INDICATING SIGNALS RADIATED FROM BOTH OF THE FIXED STATIONS AND FOR RECEIVING THE SIGNALS OF BOTH OF SAID SECOND AND THIRD CHANNELS, SAID RECEIVING MEANS BEING EFFECTIVE TO HETERODYNE THE AMBIGUITY RESOLUTION SIGNALS OF THE SECOND CHANNEL IN ORDER TO DEVELOP A FIRST DIFFERENCE SIGNAL, TO HETERODYNE THE AMBIGUITY RESOLUTION SIGNALS OF THE THIRD CHANNEL TO DEVELOP A SECOND DIFFERENCE SIGNAL, AND THE POSITION INDICATING SIGNALS TO DEVELOP A THIRD DEFFERENCE SIGNAL, AND MEANS FOR MODULATING THE ADDITIONAL SIGNALS RADIATED FROM THE REFERENCE STATION WITH REFERENCE SIGNALS RESPECTIVELY DERIVED FROM SAID FIRST, SECOND AND THIRD DIFFERENCE SIGNALS.