Frequency selection optimization in locating a utility line
AssigneeThe Charles Machine Works, Inc.
InventorsJared Hoag, Jordan Tyler Paul, Harold G. Shoemaker
Life of this patent
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Abstract
A system and method for selecting a locating-signal frequency for a buried utility line. A transmitter is coupled to the utility line and applies locating signals at multiple candidate frequencies. For each frequency, the transmitter measures the waveform of a voltage and a current associated with the locating signal and determines a corresponding phase angle. A favored frequency is identified based on the phase angles, and the transmitter applies a locating signal at the favored frequency during a locating operation. In some embodiments, standing wave ratio, impedance matching, and receiver-based signal and noise detection may also be employed.
Claims20
A method for selecting a locating-signal frequency for a buried utility line, the method comprising:
- coupling a transmitter to the buried utility line;
- applying, by the transmitter, a locating signal to the buried utility line at each of a plurality of frequencies;
- measuring, for each of the plurality of frequencies, a voltage associated with the locating signal, and a current associated with the locating signal;
- determining, for each of the plurality of frequencies, a phase angle between the measured voltage and the measured current;
- using the determined phase angles, identifying, from among the plurality of frequencies, a favored frequency;
- and
- applying, by the transmitter, a locating signal having the favored frequency during a locating operation.
A system for locating a buried utility line, the system comprising:
- a transmitter having an output interface configured to be coupled to the buried utility line, the transmitter comprising:
- a signal generator configured to apply a locating signal to the buried utility line at each of a plurality of candidate frequencies via the output interface;
- a voltage-sensing circuit configured to measure a voltage associated with the locating signal as applied to the buried utility line;
- and
- a current-sensing circuit configured to measure a current associated with the locating signal as applied to the buried utility line;
- wherein the transmitter is configured to:
- receive voltage measurements from the voltage-sensing circuit, and current measurements from the current-sensing circuit for each of the plurality of frequencies;
- determine, for each of the plurality of frequencies, a phase angle between the measured voltage and the measured current;
- and
- identify, based on the determined phase angles, a favored frequency from among the plurality of frequencies;
- and
- a receiver configured to detect the locating signal having the favored frequency at an above-ground location.
Dependencies are inferred from the claim text.