Under and above ground, radio frequency driven element, vector display, metal locating system
AssigneeGeometrics Group, Inc.
InventorLouis Dorren
Life of this patent
Estimating the term…
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.
Claims15
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.
A pipe locating system comprising:
- 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.
Dependencies are inferred from the claim text.