Under and above ground, radio frequency driven element, vector display, metal locating system
First Claim
1. A system for locating underground metal and pipe objects comprising:
- a) a transmitter for generating a RF signal, b) first connection apparatus for applying the RF signal to the underground object, c) an above ground antenna array of antenna elements for receiving RF signals transmitted by the underground object, d) a commutator for periodically and sequentially receiving signals from each antenna element in the array, the commutator frequency modulating the received signal, e) a frequency modulation detector for demodulating the signal from the commutator and providing a Doppler effect frequency shift in the transmitted signal due to the commutator, f) a vector positional display for indicating position of the object based on Doppler effect frequency shift of the demodulated signal relative to a reference signal, g) second connection apparatus for coupling the demodulated signal and the reference signal to the display, and h) a reference clock for providing the reference signal to the display.
1 Assignment
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Accused Products
Abstract
A system for locating underground or above ground metal and pipe objects includes a transmitter for generating an RF signal which is applied to the object which acts as a transmitter. An above-ground antenna array receives the RF signal transmitted by the underground object with a commutator for periodically and sequentially receiving signal from each antenna in the array, the commutator frequency modulating the received signal. A FM demodulator then demodulates the signal from the commutator and provides a Doppler effect frequency shift signal. A vector positional display then indicates position of the object based on the Doppler effect frequency shift signal relative to a reference signal.
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Citations
15 Claims
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1. A system for locating underground metal and pipe objects comprising:
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a) a transmitter for generating a RF signal, b) first connection apparatus for applying the RF signal to the underground object, c) an above ground antenna array of antenna elements for receiving RF signals transmitted by the underground object, d) a commutator for periodically and sequentially receiving signals from each antenna element in the array, the commutator frequency modulating the received signal, e) a frequency modulation detector for demodulating the signal from the commutator and providing a Doppler effect frequency shift in the transmitted signal due to the commutator, f) a vector positional display for indicating position of the object based on Doppler effect frequency shift of the demodulated signal relative to a reference signal, g) second connection apparatus for coupling the demodulated signal and the reference signal to the display, and h) a reference clock for providing the reference signal to the display. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A pipe locating system comprising:
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a) a radio frequency signal generator, b) a coupler for coupling a signal from the generator to a pipe thereby driving the pipe as a low loss transmission line radiator, c) a detector for receiving the radiated signal including a multiple element sensor array and an actuator for sequentially selecting the multiple elements to thereby frequency modulate the received signal, d) a FM demodulator for demodulating the frequency modulated signal, e) a zero crossing detector for detecting zero crossings of the demodulated signal, f) a master clock for providing a reference clock signal, and g) a display responsive to the zero crossings of the demodulated signal and the reference clock signal for indicating location of the pipe. - View Dependent Claims (12, 13, 14, 15)
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Specification