Multi-Frequency Boring Tool Locating System and Method
First Claim
1. In an overall method of operating a system in which a transmitter is moved through the ground in a region which includes an electrical conductivity characteristic, said system including an above ground arrangement for tracking the position of and/or guiding the transmitter as the transmitter moves through the ground, said transmitter being configured for transmitting a locating signal for reception by said above ground arrangement in said region for measurement of the locating signal by the above ground arrangement, the improvement comprising:
- compensating for skin depth error by measuring said locating signal such that measurements of the locating signal include skin depth error introduced as a result of said electrical conductivity characteristic and, thereafter, using said measurements in a way which determines a skin depth corrected position of the transmitter.
2 Assignments
0 Petitions
Accused Products
Abstract
Arrangements, apparatus and associated methods are described for use in a multi-frequency boring tool locating system. The boring tool includes a transmitter for transmitting a locating signal at two or more selectable frequencies. One set of above ground procedures may be applied to the transmitter in order to change the frequency of the boring tool transmitter. Another set of procedures is applicable for changing the frequency during below ground drilling operations, for example, by subjecting the boring tool to a predetermined roll orientation sequence. An enhanced portable locator operates in a manual or automatic mode to receive locating frequency information transmitted from the boring tool transmitter including frequency updates. Boring tool transmitter, as well as above ground locator shutdown/restart procedures are described relating to multi-frequency operation. A tone detector is described which implements one or more digital match filters.
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Citations
13 Claims
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1. In an overall method of operating a system in which a transmitter is moved through the ground in a region which includes an electrical conductivity characteristic, said system including an above ground arrangement for tracking the position of and/or guiding the transmitter as the transmitter moves through the ground, said transmitter being configured for transmitting a locating signal for reception by said above ground arrangement in said region for measurement of the locating signal by the above ground arrangement, the improvement comprising:
compensating for skin depth error by measuring said locating signal such that measurements of the locating signal include skin depth error introduced as a result of said electrical conductivity characteristic and, thereafter, using said measurements in a way which determines a skin depth corrected position of the transmitter. - View Dependent Claims (2, 3, 4)
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5. In a system in which a transmitter is moved through the ground in a region which includes an electrical conductivity characteristic, said system including an above ground arrangement for tracking the position of and/or guiding the transmitter as it moves through the ground using a locating signal that is transmitted from the transmitter and for reception by said above ground arrangement such that the electrical conductivity of said region results in a skin depth which modifies penetration of the locating signal into said region and, consequently, which produces skin depth error when one or more measurements of the locating signal are used, as measured by the above ground arrangement and influenced by skin depth, to determine the location of the transmitter relative to said above ground arrangement under an assumption that said region is electrically non-conductive, an apparatus comprising:
a compensation arrangement forming part of said transmitter and/or part of said above ground arrangement for compensating for skin depth error based on said measurements of said locating signal such that a skin depth corrected position of the transmitter is established.
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6. In a system in which a transmitter is moved through the ground in a region, said system including a locator for tracking the position of and/or guiding the transmitter as the transmitter moves through the ground, a method comprising:
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transmitting a locating signal from the transmitter using a transmitter that is selectively operable at a current one of at least two frequencies for use in tracking the transmitter by receiving the locating signal at the frequency with the locator; and
indicating a selected one of said frequencies of the locating signal to the locator using a frequency code that is produced by a locating signal frequency control arrangement which forms part of the transmitter, which frequency code can individually identify each of said frequencies. - View Dependent Claims (7, 8, 9, 10)
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11. In a system including a transmitter which is moved through the ground in a region, said system further including a locator for tracking the position of and/or guiding the transmitter using the locating signal, said transmitter comprising:
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a first arrangement for transmitting a locating signal at a current one of at least two locating frequencies for receipt by the locator; and
a locating signal frequency control arrangement for indicating a selected one of the locating frequencies of the locating signal to the locator using the frequency code which can individually identify each of said frequencies.
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12. In a system in which a transmitter is moved through the ground in a region, said system including a locating arrangement for tracking the position of and/or guiding the transmitter as the transmitter moves through the ground, said locating arrangement comprising:
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a configuration, forming part of said transmitter, for transmitting a locating signal at a current one of at least two locating frequencies and for transmitting a frequency designation identifying one of said frequencies of the locating signal; and
a locator which receives the frequency designation and the locating signal for use in tracking the transmitter and including a frequency tracking arrangement for switching the locator between different ones of the locating frequencies, as the current locating frequency, based on said frequency designation. - View Dependent Claims (13)
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Specification