Dual frequency distance measuring system

A radio frequency distance measuring system for determining the distance of an unknown point from a known point, which comprises:

• (a) means for providing a first signal of a given frequency and a given phase;
• (b) means responsive to said first signal for generating a first continuous wave carrier signal of a first frequency;
• (c) means responsive to said first signal for generating a second continuous wave carrier signal of a second frequency, said second frequency displaced from said first frequency by a selected difference frequency;
• (d) means for radiating said first and second continuous wave carrier signals;
• and
• (e) means for receiving said first and second continuous wave carrier signals at said unknown point to provide a difference frequency signal used in determining said distance.

A radio frequency position measuring system for calculating the position of an unknown point from at least two known points, which comprises:

• (a) means for producing a first signal of a given frequency and a given phase;
• (b) means responsive to said first signal for generating a first continuous wave carrier signal of a first frequency;
• (c) means responsive to said first signal for generating a second continuous wave carrier signal of a second frequency, said second frequency displaced from said first frequency by a first selected difference frequency;
• (d) means at said first known point for radiating said first and second continuous wave carrier signals;
• (e) means for producing a second signal of said given frequency and of a predetermined phase relationship with respect to said given phase;
• (f) means responsive to said second signal for generating a third continuous wave carrier signal of a third frequency;
• (g) means responsive to said second signal for generating a fourth continuous wave carrier signal of a fourth frequency displaced from said third frequency by a second selected difference frequency;
• (h) means at said second known point for radiating said third and fourth continuous wave signals;
• (i) means at said unknown point for receiving said first and second continuous wave carrier signals to provide a first difference frequency signal and for receiving said third and fourth continuous wave carrier signals to provide a second difference frequency signal, said first and second difference frequency signals used in determining the position of said unknown point with respect to said first and second known points.

A radio frequency distance measuring system, which comprises:

• (a) transmitter means located at a known point, which includes
• (i) means for generating a first standard signal of a selected frequency and selected phase,
• (ii) means responsive to said first standard signal for producing a first continuous wave carrier signal of a first frequency,
• (iii) means responsive to said first standard signal for producing a second continuous wave carrier signal of a second frequency, said second frequency displaced from said first frequency by a selected difference frequency, and
• (iv) means for radiating said first and second continuous wave carrier signals;
• and
• (b) means located at an unknown point, which includes
• (i) means for generating a second standard signal of said selected frequency and of a predetermined phase relationship with respect to said selected phase,
• (ii) means for receiving said first continuous wave carrier signal and said second continuous wave carrier signal,
• (iii) means for mixing said receiving first and second continuous wave carrier signals to obtain a frequency difference signal,
• (iv) means for providing a reference signal in accordance with said second standard signal, and
• (v) means for determining the distance between said known point and said unknown point by comparing the phase difference between said reference signal and said frequency difference signal.

A radio frequency distance measuring method for determining the distance between an unknown point and a known point, which comprises the steps of:

• (a) producing a first signal of a given frequency and a given phase;
• (b) generating in response to said first signal a first continuous wave carrier signal of a first frequency;
• (c) generating in response to said first signal a second continuous wave carrier signal of a second frequency, said second frequency displaced from said first frequency by a selected difference frequency;
• and
• (d) radiating said first and second continuous wave carrier signals for reception at said unknown point to provide a difference frequency signal used in determining said distance.

A radio frequency distance measuring method for determining the distance of an unknown point from a known point, which method comprises the steps of:

• (a) generating a first signal of a given frequency and of a given phase;
• (b) generating as a function of said first signal a first continuous wave carrier signal of a first frequency;
• (c) generating as a function of said first signal a second continuous wave carrier signal of a second frequency, said second frequency displaced from said first frequency by a selected difference frequency;
• (d) radiating from said known point said first and second continuous wave carrier signals;
• (e) receiving at said unknown point said first and second continuous wave carrier signals;
• (f) mixing said received first and second continuous wave carrier signals for producing a difference frequency signal used in determining said distance.