Device for locating a boring machine
First Claim
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1. An assembly for locating the position of an object, comprising:
- (a) first means located at said object for generating an electromagnetic field at a given frequency;
(b) second means remote from said first means and including first and second signal receiving antennas located a fixed distance apart for simultaneously producing continuous first and second electrical input signals containing relatively high frequency noise and having AC components which are at said given frequency and which have amplitudes proportional to the strength of said field at said first and second antennas, respectively;
(c) signal processing circuitry electrically connected to said second means and including(i) multiplexing means for producing a continuous train of alternating, discrete first and second signal segments from and corresponding to discrete segments of said continuous first and second signals,(ii) a single synchronous detector operating on said continuous train of alternating, discrete first and second signal segments at a frequency at least approximating said given frequency for substantially reducing the frequency of the AC components of said first and second signal segments,(iii) demultiplexing means electrically connected to said synchronous detector for separating said discrete first and said second signal segments into first and second electrical output signals containing relatively high frequency noise and having AC components corresponding to said first mentioned AC components but at a substantially reduced frequency, and(iv) means electrically connected to said demultiplexing means for filtering out the relatively high frequency noise from said combined first and second output signals; and
(d) means acting on said filtered out first and second output signals for determining there from the distance between said object and said antennas.
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Abstract
An assembly is disclosed herein for locating an underground object that is transmitting a relatively low frequency signal electromagentic field. Means are provided for scanning the earth'"'"'s surface and homing in on the point where the magnetic field is strongest, and at that point, calculating the depth of the object based on the strength of the magnetic field.
89 Citations
20 Claims
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1. An assembly for locating the position of an object, comprising:
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(a) first means located at said object for generating an electromagnetic field at a given frequency; (b) second means remote from said first means and including first and second signal receiving antennas located a fixed distance apart for simultaneously producing continuous first and second electrical input signals containing relatively high frequency noise and having AC components which are at said given frequency and which have amplitudes proportional to the strength of said field at said first and second antennas, respectively; (c) signal processing circuitry electrically connected to said second means and including (i) multiplexing means for producing a continuous train of alternating, discrete first and second signal segments from and corresponding to discrete segments of said continuous first and second signals, (ii) a single synchronous detector operating on said continuous train of alternating, discrete first and second signal segments at a frequency at least approximating said given frequency for substantially reducing the frequency of the AC components of said first and second signal segments, (iii) demultiplexing means electrically connected to said synchronous detector for separating said discrete first and said second signal segments into first and second electrical output signals containing relatively high frequency noise and having AC components corresponding to said first mentioned AC components but at a substantially reduced frequency, and (iv) means electrically connected to said demultiplexing means for filtering out the relatively high frequency noise from said combined first and second output signals; and (d) means acting on said filtered out first and second output signals for determining there from the distance between said object and said antennas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An assembly for locating the position of an object, comprising:
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(a) first means located at said object for generating an electromagnetic field at a given frequency; (b) second means remote from said first means and including a plurality of signal receiving antennas, each located a fixed distance apart, for simultaneously producing a plurality of continuous electrical input signals containing relatively high frequency noise and having AC components which are at said given frequency and which have amplitudes proportional to the strength of said field at said respective antennas; (c) signal processing circuitry electrically connected to said second means and including (i) multiplexing means for producing a continuous train of alternating, discrete signal segments from and corresponding to discrete segments of said plurality of continuous input signals, (ii) a single synchronous detector operating on said continuous train of alternating, discrete signal segments at a frequency at least approximating said given frequency for substantially reducing the frequency of the AC components of said plurality of signal segments, (iii) demultiplexing means electrically connected to said synchronous detector for converting said continuous train of alternating, discrete signal segments into a plurality of electrical output signals corresponding to the number of input signals, said plurality of electrical signals containing relatively high frequency noise and having AC components corresponding to said first mentioned AC components but at a substantially reduced frequency, and (iv) means electrically connected to said demultiplexing means for filtering out the relatively high frequency noise from said plurality of electrical signals; and (d) means acting on said plurality of filtered out signals for determining therefrom the distance between said object and said plurality of antennas. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. An apparatus to remove in continuous time noise from a plurality of AC signals at a given frequency, the apparatus comprising:
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multiplexer means for receiving said plurality of signals, each of said signals being present on a signal channel and having signal noise of a different frequency than said given frequency, said multiplexer periodically selecting one of said signals as its output, a single synchronous detector electrically coupled to said multiplexer output and engaged to modulate said selected signal with a reference signal to substantially reduce its given frequency; a demultiplexer, electrically coupled to said synchronous detector and acting in cooperation with said multiplexer, returning said multiplexed and modulated signal to its said respective signal channel for signal processing; means for filtering out said signal noise from said modulated signals electrically coupled to said demultiplexer; and means electrically coupled to said multiplexer and demultiplexer for controlling the multiplexer and demultiplexer so that each of the plurality of signals time share the single synchronous detector.
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19. An apparatus for calculating and displaying a plurality of orders of an underground object'"'"'s location and depth;
- said apparatus comprising;
transmitting means located at said object for transmitting a homing signal; receiving means for receiving said homing signal; signal processing means electrically coupled to said receiving means for sampling said received homing signal over a plurality of predefined time intervals, and for each said predefined time interval, said signal processing means calculating an object location and depth value based on the signal samples taken during said corresponding predefined time interval and including a signal noise filtering assembly in which multiplexed signals pass sequentially through a demultiplexer, selected ones of a plurality of filters and a multiplexer; and a display means coupled to said signal processing means for displaying each order of said location and depth values. - View Dependent Claims (20)
- said apparatus comprising;
Specification