Electronic surveying system

Claim 1

IN AN ELECTRONIC SURVEYING SYSTEM FOR MEASURING THE SLANT RANGE BETWEEN A FIRST STATION AT A FIRST LOCATION, SPATIALLY SEPARATED FROM A SECOND STATION AT A SECOND LOCATION, THE FIRST STATION INCLUDING MEANS FOR GENERATING AND TRANSMITTING A FIRST CARRIER SIGNAL, AND MEANS ADAPTED TO RECEIVE A SECOND CARRIER SIGNAL, THE SECOND STATION INCLUDING MEANS FOR GENERATING AND TRANSMITTING A SECOND CARRIER SIGNAL, AND MEANS ADAPTED TO RECEIVE THE FIRST CARRIER SIGNAL, THE COMBINATION COMPRISING: FIRST MEANS AT THE FIRST STATION FOR GENERATING A FIRST RANGING SIGNAL AT A FREQUENCY W1 AND FOR MODULATING SAID FIRST RANGING SIGNAL UPON THE FIRST CARRIER SIGNAL FOR TRANSMISSION THEREWITH; SECOND MEANS AT THE SECOND STATION FOR GENERATING FIRST AND SECOND CALIBRATING SIGNALS AT FREQUENCIES, W2 AND WR/N, RELATED BY THE WHOLE INTEGER N; THIRD MEANS CONNECTED TO SAID SECOND MEANS AND ADAPTED TO RECEIVE AND EXTRACT THE TRANSMITTED FIRST RANGING SIGNAL FOR GENERATING FIRST AND SECOND COMPOSITE SIGNALS AT FREQUENCIES W2 AND W3, RESPECTIVELY, WHERE W2=W1+WR AND W3=W2+WR/N IN PREDETERMINED PHASE SYNCHRONISM WITH THE RECEIVED FIRST RANGING SIGNAL; FOURTH MEANS CONNECTED TO SAID THIRD MEANS FOR MODULATING SAID FIRST AND SECOND COMPOSITE SIGNALS ON THE SECOND CARRIER SIGNAL FOR TRANSMISSION TO THE FIRST STATION; FIFTH MEANS AT THE FIRST STATION COUPLED TO SAID FIRST MEANS FOR RECEIVING SAID FIRST AND SECOND COMPOSITE SIGNALS AND FOR EXTRACTING THEREFROM SAID FIRST AND SECOND CALIBRATIONG SIGNALS; SIXTH MEANS CONNECTED TO SAID FIFTH MEANS FOR CONVERTING SAID FIRST AND SECOND CALIBRATING SIGNALS TO A COMMON FREQUENCY AND FOR QUANTIZING THE PHASE DIFFERENCE EXISTING THEREBETWEEN; AND SEVENTH MEANS CONNECTED TO SAID SIXTH MEANS AND RESPONSIVE TO SAID QUANTIZED PHASE DIFFERENCE TO DISPLAY A NUMBER CORRESPONDING TO THE SPATIAL SEPARATION BETWEEN THE STATIONS,