Dual frequency distance measuring system
First Claim
1. A transmitting station in a radio frequency distance measuring system utilized to determine the distance of a unknown point from a known point, which comprises:
- (a) stable frequency source 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; and
(d) means for radiating said first and second continuous wave carrier signals for reception at said unknown point for providing a difference frequency signal for determining said distance.
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Accused Products
Abstract
A radio frequency distance measuring system and method where two continuous wave carrier signals, derived from a stable frequency source, are radiated from a known reference point. The frequency of the first continuous wave carrier signal is displaced from the frequency of the second continuous wave carrier signal by a selected difference frequency. When received at the unknown point, the two continuous wave carrier signals are mixed to provide a difference or beat frequency marker signal, delayed in arrival at the unknown point from the known point by the speed of light. A locally generated marker signal is derived from a stable frequency source at the unknown point, and has the same frequency as the difference frequency signal. The leading or trailing edge of the difference frequency signal can be compared with the locally generated marker signal, and the time difference or phase difference between them can be displayed using a phase meter or time interval indicator and corresponds to determine directly the distance between the known transmitter reference point and the unknown receiver point. Multiple known reference point transmitters, each transmitting two continuous wave carrier signals displaced in frequency by a selected difference frequency, can be used to obtain two or more distance measurements at the unknown point to determine the position of the unknown receive point with respect to the known transmitter points. A chart shows the relationship of the selected difference frequency to the distance that can be measured without ambiguity.
58 Citations
44 Claims
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1. A transmitting station in a radio frequency distance measuring system utilized to determine the distance of a unknown point from a known point, which comprises:
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(a) stable frequency source 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; and (d) means for radiating said first and second continuous wave carrier signals for reception at said unknown point for providing a difference frequency signal for determining said distance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A radio frequency distance measuring system for determining the distance of an unknown point from a known point, which comprises:
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(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. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A radio frequency position measuring system for calculating the position of an unknown point from at least two known points, which comprises:
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(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.
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31. A radio frequency distance measuring system, which comprises:
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(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. - View Dependent Claims (32, 33)
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34. A radio frequency distance measuring method for determining the distance between an unknown point and a known point, which comprises the steps of:
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(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. - View Dependent Claims (35, 36, 37, 38, 39, 40)
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41. A radio frequency distance measuring method for determining the distance of an unknown point from a known point, which method comprises the steps of:
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(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. - View Dependent Claims (42, 43, 44)
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Specification