Electronic distance measuring device and method

Claim 2

Apparatus for measuring the distance between two geographically separated locations comprising means including a first variable frequency oscillator for transmitting wave energy at a first frequency from one of such locations to the other, means at the one location for detecting the wave energy reflected from the other location, means for varying the frequency of said first oscillator until a preascertained phase relationship is obtained between the transmitted wave energy and the detected wave energy, means including a second variable frequency oscillator for transmitting wave energy from one of such locations to the other, means for varying the frequency of said second oscillator with respect to the frequency of said first oscillator, until a preascertained phase relationship is obtained between the transmitted wave energy of the second oscillator and the detected wave energy returned from the other location, latter phase relationship being different frequency-wise from the phase relationship associated with said first oscillator, thus establishing a predetermined integral multiple of one-half wavelengths difference between the number of wavelengths of the first and second frequencies, means for subtracting the smaller from the larger of the two frequencies to obtain a resultant difference frequency inversely proportional to the distance between the first and second locations, means for converting the difference frequency into a count accurately representative of the distance between the two locations, and means for indicating the distance between the two locations.

Claim 3

The apparatus of claim 1 wherein said means for indicating the distance includes means for generating an electrical signal related in frequency to the difference between the first and second frequencies of the transmitted wave energy; and means responsive to said electrical signal for digitally displaying the distance between the two predetermined locations.

Claim 4

The apparatus of claim 1 wherein said transmitting means includes: means for generating a continuous wave carrier beam of wave energy; and modulator means for amplitude modulating said continuous wave carrier beam of wave energy responsively to an applied modulating signal.

Claim 5

The apparatus of claim 3 wherein said means for detecting the wave energy comprises detector means for detecting the amplitude modulation of said continuous wave carrier beam.

Claim 6

Apparatus for measuring the distance between two geographically separated locations comprising a pair of variable frequency oscillators, means including a first of said oscillators for transmitting wave energy at a first frequency from one of said locations to the other, means at the one location for detecting the wave energy reflected from the other location, means for varying the frequency of said first oscillator until a phase null is obtained between the transmitted wave energy and the detected wave energy, means for bringing the second oscillator to the frequency of said first oscillator, means for varying the frequency of said second oscillator while holding fixed the frequency of said first oscillator, until a phase null is obtained between the transmitted wave energy of the second oscillator and the detected wave energy returned from the other location, latter phase null being different frequency-wise from the phase null associated with said first oscillator, thus establishing a predetermined integral multiple of one-half wavelengths difference between the number of wavelengths of the first anD second frequencies, means for subtracting the smaller from the larger of the two frequencies to obtain a resultant difference frequency inversely proportional to the distance between the first and second locations, means for applying a time gate to a stable oscillator, said time gate being one or more cycles of the difference frequency, and means for counting the number of cycles of the gated frequency output from said stable oscillator, and for indicating in a highly accurate manner, the distance between the two locations.

Claim 7

Apparatus for measuring the distance between two geographically separated locations comprising a pair of variable frequency oscillators, means including a first of said oscillators for transmitting wave energy at a first frequency from one of said locations to the other, means at the one location for detecting the wave energy reflected from the other location, means for varying the frequency of said first oscillator until a phase null is obtained between the transmitted wave energy and the detected wave energy, means for bringing the second oscillator to the frequency of said first oscillator, means for varying the frequency of said second oscillator while holding fixed the frequency of said first oscillator, until a phase null is obtained between the transmitted wave energy of the second oscillator and the detected wave energy returned from the other location, latter phase null being different frequency-wise from the phase null associated with said first oscillator, thus establishing a predetermined integral multiple of one-half wavelengths difference between the number of wavelengths of the first anD second frequencies, means for subtracting the smaller from the larger of the two frequencies to obtain a resultant difference frequency inversely proportional to the distance between the first and second locations, means for applying a time gate to a stable oscillator, said time gate being one or more cycles of the difference frequency, and means for counting the number of cycles of the gated frequency output from said stable oscillator, and for indicating in a highly accurate manner, the distance between the two locations.

Claim 8

The apparatus of claim 5 wherein said means for indicating the distance includes: means for generating an electrical signal related in frequency to the difference between said first and said second frequencies of the wave energy; and means responsive to said electrical signal for digitally displaying the distance between the two predetermined locations.

Claim 9

The apparatus of claim 6 wherein said transmitting means includes: means for generating a continuous wave carrier beam of wave energy; and, modulator means for amplitude modulating said continuous wave carrier beam of wave energy respectively to an applied modulating signal.

Claim 12

The method of claim 8 including the steps of dividing the difference frequency by a predetermined integer and gating the electrical signal to the counter responsively thereto.

Claim 13

The method of claim 8 wherein the varying of the frequency of the transmitted wave energy includes the generation of a second wave energy signal during a common time period.

Claim 14

The method of claim 8 wherein the difference frequency is obtained by: storing a number related to the number of cycles of one of the first and second frequency wave energy during a first period of time; reducing the stored number by a number related to the number of cycles of the other of the first and second frequency wave energy during a second period of time of the same duration as the first period of time.

Claim 19

Apparatus for accurately measuring the distance between two geographically separated locations comprising means for transmitting a wave energy signal at a first selected frequency from a first location to a second location, means at the second location for reflecting the transmitted wave energy back from such second location to the first location, means at the first location for receiving and detecting the signal reflected from said reflector means, means for adjusting the frequency of the first transmitted signal by the use of a phase comparison means such that an integral number of quarter wavelengths exist over the distance from the source to the reflector means and back, means for transmitting a second wave energy signal, from such first location to said reflector means at a second frequency, said second frequency bearing a preascertained relationship to said first frequency, means for adjusting the frequency of the second signal such that an integral number of quarter wavelengths exist over the distance from such first location to said reflector means and back, which is one half wavelength greater or less than the number of wavelengths at the first frequency, means for holding substantially constant the phase relationships of the first and second frequencies while rapidly alternating the transmission between the first and second frequencies, thereby making both frequencies simultaneously available for processing for distance measurement, means for subtracting the smaller frequency from the larger of the two frequencies so as to obtain and identify a difference frequency inversely proportional to the distance between such first location and said reflector means, without it being necessary to establish the numerical frequency of either the first frequency or the second frequency, means for dividing such difference frequency by a selected constant so as to obtain a time gate, means for applying such time gate to stable oscillator means to obtain a count directly proportional to distance, and, means for displaying such count on an indicating means, thus to represent precisely the distance between the first location and the second location.

Claim 20

Apparatus for accurately measuring the distance between two geographically separated locations comprising means for transmitting a wave energy signal at a first selected frequency from a first location to a second location, means at the second location for reflecting the transmitted wave energy back from such second location to the first location, means at the first location for receiving and detecting the signal reflected from said reflector means, means for adjusting the frequency of the first transmitted signal by the use of a phase comparison means such that an integral number of quarter wavelengths exist over the distance from the source to the reflector means and back, means for transmitting a second wave energy signal, from such first location to said reflector means at a second frequency, said second frequency bearing a preascertained relationship to said first frequency, means for adjusting the frequency of the second signal such that an integral number of quarter wavelengths exist over the distance from such first location to said reflector means and back, which is one half wavelength greater or less than the number of wavelengths at the first frequency, means for holding substantially constant the phase relationships of the first and second frequencies while rapidly alternating the transmission between the first and second frequencies, thereby making both frequencies simultaneously available for processing for distance measurement, means for subtracting the smaller frequency from the larger of the two frequencies so as to obtain and identify a difference frequency inversely proportional to the distance between such first location and said reflector means, without it being necessary to establish the numerical frequency of either the first frequency or the second frequency, means for dividing such difference frequency by a selected constant so as to obtain a time gate, means for applying such time gate to stable oscillator means to obtain a count directly proportional to distance, and, means for displaying such count on an indicating means, thus to represent precisely the distance between the first location and the second location.

Claim 23

An electronic distance measuring device for determining the distance between two geographically spaced locations utilizing wave energy, comprising means for transmitting wave energy from one location to the other, means at said one location for detecting the wave energy reflected back from said other location and for comparing same in phase with the transmitted wave energy, means for varying the phase relationship between the transmitted and detected energy until a predetermined phase lock relationship exists, said means for transmitting wave energy then transmitting wave energy from the one location to the other at a different frequency until a predetermined phase lock realtionship exists at such different frequency, means for accomplishing a rapid alternate trnasmission of the two frequencies, while maintaining both frequencies in the desired phase lock conditions, means for subtracting one of such frequencies from the other to obtain a difference frequency, such difference frequency then being utilized for providing a direct indication of distance between the two geographically spaced locations.

Claim 24

An electronic distance measuring device for determining the distance between two geographically spaced locations utilizing wave energy, comprising means for transmitting wave energy from one location to the other, means at said one location for detecting the wave energy reflected back from said other location and for comparing same in phase with the transmitted wave energy, means for varying the phase relationship between the transmitted and detected energy until a predetermined phase lock relationship exists, said means for transmitting wave energy then transmitting wave energy from the one location to the other at a different frequency until a predetermined phase lock realtionship exists at such different frequency, means for accomplishing a rapid alternate trnasmission of the two frequencies, while maintaining both frequencies in the desired phase lock conditions, means for subtracting one of such frequencies from the other to obtain a difference frequency, such difference frequency then being utilized for providing a direct indication of distance between the two geographically spaced locations.