Device for determining depth and direction of buried objects
First Claim
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1. Buried object locating apparatus comprising:
- a transmitter for supplying a location current having a selected frequency and phase for forming an alternating field around the buried object,a receiver for detecting the position of the buried object on the basis of the detected value of said alternating field,a reference signal transmitter for transmitting a reference signal having the same frequency and phase as that of said location current, anda means for receiving said reference signal,said receiver including;
a detection unit equipped with a first detection coil located in a first, upper, position and a second detection coil located in a second, lower position,an analog signal processor unit equipped with a multiplier for the output signal transmitted from said detection unit and the reference signal transmitted from said reference siganl transmitter, and a filter for the output from the multipler,a calculation processing unit equipped with a n A/D converter for converting the output signal transmitted from the analog signal processing unit into a digital signal, anda microprocessor for calculating the position of the buried object by using the difference between the output signals of said detection coil located in said first, upper position and that of said detection coil located in said second, lower position, anda display unit for displaying the results of said calculation by said microprocessor.
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Abstract
Apparatus for locating buried objects such as underground pipes, cables or the like where a transmitter (1) generates an alternating current signal which is fed into the object to produce an alternating field emanating from the object, and a receiver (2) locates this radiation to identify the position of the object. A secondary transmitter (T) transmits a reference signal of the same frequency and phase as the original signal, and a signal processor in a receiver (2a) combines the two signals to eliminate the effects of noise.
72 Citations
7 Claims
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1. Buried object locating apparatus comprising:
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a transmitter for supplying a location current having a selected frequency and phase for forming an alternating field around the buried object, a receiver for detecting the position of the buried object on the basis of the detected value of said alternating field, a reference signal transmitter for transmitting a reference signal having the same frequency and phase as that of said location current, and a means for receiving said reference signal, said receiver including; a detection unit equipped with a first detection coil located in a first, upper, position and a second detection coil located in a second, lower position, an analog signal processor unit equipped with a multiplier for the output signal transmitted from said detection unit and the reference signal transmitted from said reference siganl transmitter, and a filter for the output from the multipler, a calculation processing unit equipped with a n A/D converter for converting the output signal transmitted from the analog signal processing unit into a digital signal, and a microprocessor for calculating the position of the buried object by using the difference between the output signals of said detection coil located in said first, upper position and that of said detection coil located in said second, lower position, and a display unit for displaying the results of said calculation by said microprocessor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification