Abstract: A self-tuning resonator for use in a transmitter apparatus for inducing alternating currents in a buried conductor. The resonator is dynamically tuned at frequencies below 500 kHz by exploiting the inherent voltage-variability of net capacitance in multilayer ceramic capacitors. The transmitter apparatus provides improved efficiency and induced output power suitable for use in a man-portable locator system, providing a very high magnetic field output from a physically small battery-powered resonator at frequencies under 500 kHz. The resonator exhibits a very low equivalent series resistance (ESR) and is adaptively returned to a predetermined resonant frequency responsive to any changes in resonance arising from phenomena such as component heating, thereby supporting very high tank circuit currents from battery-powered source to produce very high magnetic flux output.

Abstract: Systems and methods presented herein are generally directed to the location and/or identification of a circuit within a circuit. In one embodiment, a transmitter is configured for inducing a signal upon a circuit (e.g., power lines, communication lines, lighting circuits, etc.) to identify it from other circuit lines. The signal may be induced upon an individual element of the circuit through direct contact. A receiver may receive a radiated component of the signal from a distal point on the circuit to acquire the signal induced thereon and determine a strength of the signal received. Based on the received signal component, the receiver may determine location, configuration, and/or identification of the circuit from which the radiated signal is being received.

Abstract: A mine detector has a search head with a transmitting unit for the transmission of signal sequences into the ground, and a metal detection unit. A distance measurement sensor is arranged on the search head for determination of the current geometric distance of the search head from the ground. The response signal sensor and the distance measurement sensor are each connected for dataflow purposes to a measurement data logic unit which can be supplied with ground distance measurement data when the distance between the search head and the ground surface changes, in order to produce a distance/signal strength curve. The measurement data logic unit is connected for data interchange purposes to a curve comparison unit, which is itself connected for data interchange purposes to a standard curve and algorithm storage unit and can be supplied from there with the standard distance/signal strength curves and algorithms.

Abstract: A boring tool is moved through the ground in a region which includes at least one electrically conductive in-ground line and which is subject to static magnetic fields including the magnetic field of the earth.

Abstract: A cable detection apparatus is disclosed having a filter, the filter transmitting components of a signal detected substantially at certain harmonics of a first frequency. The filter may also attenuate the signal at certain even harmonics thereof. A method of detecting and/or locating cables in the same manner is also disclosed.

Abstract: A drilling system performs underground boring using a drill rig and a boring tool which is configured for moving through the ground under control of the drill rig to form an underground bore. A monitoring arrangement, forming part of the system, includes a detection arrangement at the drill rig for monitoring at least one operational parameter to produce a data signal relating to at least one of a utility to be installed in the underground bore, the drill rig and the boring tool. A portable device forms another part of the system for receiving the data signal relating to the operational parameter for use by the portable device. A communication arrangement, for example using telemetry, transfers the data signal from the drill rig to the portable device. The operational parameter may be monitored for the purpose of preventing equipment failure.

Abstract: Measurement of the location and direction of a drill head in a borehole extending beneath an obstacle such as a body of water utilizes a single AC solenoid at a known location but having an unknown orientation. The measurements are used to direct the path of the borehole.

Abstract: Tracking a boring tool is performed within an underground region using a locating signal. The boring tool is moved through the ground during a series of distance movements such that potential movement of the boring tool during any one of the distance movements is less than a maximum movement value. A current positional relationship is determined for a current one of the distance movements based on: a last-determined positional relationship established for an immediately preceding one of the distance movements, certain orientation parameters, the maximum movement value and the determined signal strength of the locating signal in the current positional relationship. Target coordinates are accepted and a target position, based on the target coordinates, is included as part of the current positional relationship. The position of the target is unconstrained with respect to system geometry. Steering command features are provided along with steering warnings.

Abstract: A system and method of interfacing a drilling machine with one of a number of different walk-over guidance systems involves receiving an ID signal from a particular walk-over guidance system selected for use with the drilling machine. A protocol library associated with the particular walk-over guidance system is accessed in response to the ID signal. The protocol library is used to effect communication between the particular walk-over guidance system and a control system of the drilling machine during cooperative use of the particular walk-over guidance system and drilling machine. Using the protocol library involves converting, as prescribed by the protocol library, locator signals received from the particular walk-over guidance system from a locator protocol to a common protocol used by the control system of the drilling machine. Locator and drilling machine data of various types can be presented to a drilling machine operator via an on-board display.

Abstract: A signaling apparatus comprises a magnet and a shield moveable relative to the magnet. The shield is moveable relative to the magnet between a first position in which the magnet is relatively exposed and a second position in which the magnet is relatively shielded. The apparatus can include a synchronization signal source, a downhole sensor signal source, and/or means for modulating the magnetic field in response to the signal from any source. A method of using the signaling apparatus to locate a bottomhole assembly includes moving the shield so as to modulate the magnetic field created by the magnet, sensing the modulation of the magnetic field, and determining the location of the bottomhole assembly using the information collected. The BHA can be located using phase shift or amplitude measurements. Receivers detecting the modulated magnetic field can be at or below the earth's surface.

Abstract: In order to control the sonde of an underground object, such as an underground boring tool, a predetermined sequence of rotation steps is applied to the object and that sequence is detected. The detection of the appropriate sequence causes the sonde to change its function, for example by changing the carrier frequency of the signal transmitted by the sonde on to change the data output sequence or transfer rate, or to change output power. While it is possible to use a single rotation step, the use of more than one step, with each step to be carried out within a predetermined time, reduces the risk of error.

Abstract: A portable area monitoring system for use with a horizontal directional drilling machine and adapted to produce a composite of the positions of a beacon and a fixed object. In a preferred embodiment the sensor assembly is supported by a hand-held frame and adapted to detect signals emanating from each of a beacon and a fixed object. The sensor assembly transmits the detected signals to a processor which simultaneously processes the signals to produce a composite of relative positions of the beacon and the fixed object to the frame. The composite of the relative positions of the beacon and the fixed object to the frame is communicated to the operator using a portable display.

Abstract: An embodiment of the invention provides a sensing device that includes a sensing circuit and a mode selection input device. The sensing circuit senses the presence of an object beneath a surface. The mode selection input device allows a user to select, using a single button, a desired mode from among at least three sensitivity modes without first accessing another sensitivity mode. In another embodiment, a sensing device includes a sensing circuit and a display. The sensing circuit senses the presence of a live electrical wire beneath a surface. The display includes an optical element and a light source to indicate the sensed presence of the live electrical wire.

Abstract: A portable locator and method for establishing the location of the cable line in a region which includes at least one generally straight electrically conductive cable line extending across the region from which cable line a locating signal includes a first arrangement for measuring a local flux intensity of the locating signal at a first above ground point within the region with the portable locator in a particular orientation at the first above ground point. A second arrangement uses the local flux intensity to establish a cable line angular orientation which limits the possible directions to the cable line relative to the particular orientation of the portable locator at the above ground point. A third arrangement uses the measured local flux intensity to establish an actual direction of the cable line that is selected from the possible directions based on certain characteristics of the locating signal.

Abstract: A forwarding looking ground penetrating mine detection apparatus includes a radiation source for irradiating a sample of ground suspected of containing at least one mine with a plurality of frequency swept ground penetrating radar signals. A detector receives target signals backscattered from the ground responsive to the radar signal. The detector includes a time-frequency analyzer which transforms the target signals into a time-frequency image representation (TFR). In a preferred embodiment, the detector can include a wavelet packet transformer (WPT) for extracting time-frequency localized information from the TFR in the form of feature set constructed from a wavelet table. The apparatus can also include a data dimensionality reducer for selecting features to form a feature subset from the feature set, preferably based on reference to a training data set. A multilayer neural network classifier can be based on the feature subset, and be adaptable to the surrounding environment through learning.

Abstract: The present invention provides a locator/monitor capable of locating a boring tool and monitoring the progress of the tool for control purposes. The locator/monitor may be used in expedited locating methodology and straightforward calibration techniques of the present invention. A durable and cost effective pitch sensor is also provided by the present invention. In addition, the present invention provides a slotted transmitter housing formed of an electrically conductive material, where the magnetic field generated by the transmitter is capable of penetrating to the surface.

Abstract: A dynamic magnetic locator includes a linking mechanism linked with a first sensor to horizontal move or rotate the first sensor; a second sensor horizontally arranged beside the first sensor; a third sensor vertically arranged atop the second sensor; and a control module connected to the sensors and receiving magnetic signals of the underground metal pipe. The control module controls the linking mechanism to horizontal move or to rotate the first sensor to obtain a plurality of magnetic signals. The control module processes the magnetic signals to obtain a position and a depth of an underground metal pipe.

Abstract: A device in which the receiver coil of a pulse inductive metal detector is capable of switching between a differential configuration (i.e., gradiometer configuration) to a non-differential or summing configuration under control of the operator or computer.

Abstract: An above ground locator includes an apparatus for determining the strength of the locating signal at a selected point relative to the boring tool. The apparatus includes an antenna arrangement configured for measuring the strength of the locating signal at the selected point along first and second orthogonally opposed receiving axes to produce first and second received signals. A phase shifting arrangement phase shifts the first and second received signals in a predetermined way to generate first and second phase shifted signals, respectively. Thereafter, a summing arrangement adds the first and second phase shifted received signals to generate an output signal which is a vector sum of the first and second received signals. In one feature, third and fourth signals derived from the first and second signals are used to eliminate balance point ambiguity which is present using the first and second signals alone.

Abstract: A system and method for locating a horizontal bore below a ground surface includes a transmitting source configured to radiate from the bore a dipole magnetic field aligned with the bore. A receiver is located remote from the transmitting source and has a first coil and a second coil. Each coil defines an axis, wherein the axes of the first coil and the second coil are orthogonal to each other. A measurement device is in communication with the coils and configured to measure the phase of signals induced on the coils by the magnetic field when the axis of the first coil is horizontally perpendicular to the axis of the magnetic field and the axis of the second coil is vertically perpendicular to the axis of the magnetic field. The measurement device is also configured to determine the lateral position of the transmitting source relative to the coils responsively to the phase of the signals on the first coil and the second coil.

Abstract: Discriminating between a cable locating signal and a false cable locating signal is described. A reference signal, which contains a locating signal frequency impressed on it, is transmitted in a way which provides for detection of a phase shift between the locating signal and the false locating signal. Based on the phase shift, a receiver is used to distinguish the locating signal from the false locating signal.

Abstract: A device and method to improve pulse inductive metal detector (MD) sensitivity uses multiple, current steps to reduce the voltage rating of electronic components. Current reduction in one implementation is done with multiple switched resistors coupled to a voltage source and connected to the transmitter coil. The current reduction in another implementation is done with multiple switched current sources that are connected to the transmitter coil and are switched inactive one by one to reduce the total current to the transmitter coil. The current is stepped down in rapid secession with a time delay between current transitions less than the time constant of the metal target under investigation.

Abstract: A blind locating system for finding and tracing buried objects such as utility lines, conductive pipes and sondes. A sensor array is coupled to a signal processor, which determines a field vector for one or more buried objects by producing a data signal representing a covariance matrix corresponding to the covariances of the time-varying sensor array signals over a selected frequency band and accumulation interval. The covariance matrix is characterized by eigenvalues and associated eigenvectors and a user interface (UI) indicates the field vector associated with the eigenvector having the largest eigenvalue. Using several different frequency bands, a plurality of underground objects may be simultaneously detected and indicated in the UI without foreknowledge of their existence or characteristics.

Abstract: A detection system is provided which is configured to have a transmitter capable of interacting with an object by generating a field, and a multiplicity of receivers operative to measure changes in the environment caused by the object's response to the generated field and mounted to a closed-looped belt, which is displaceable in a proximity to the object.

Abstract: The present invention provides systems and methods which can be employed to locate or detect presence of various materials, including nonferrous metals. These systems include new and useful sensors, circuits, systems and devices which power and/or interoperate with the sensors, and methods of making, operating and using such systems. Any or all of the systems, devices or processes can be combined with other systems, devices or processes disclosed.

Abstract: A data sonde for use in horizontal drilling is provided, the data sonde comprising an antenna for emitting a first modulated signal from the data sonde, the first signal comprising zero and non-zero emission components in different periods, and a receiver for receiving an intermittent second data signal during first signal zero emission periods. A method of operation of the same is also provided.

Abstract: The invention relates to a transmitter loop configuration used for ground and downhole electromagnetic geophysical surveys. The loop wire is spread out on the ground surface in such a way as to form several subset loops in series. Each subset loop can be juxtaposed to each other or separated by a fixed distance. The contribution of each subset to the primary electromagnetic field is improved in intensity and vector orientation so as to energize more efficiently buried geological conductors. This design generates a strong sub-horizontal primary field in an in-loop zone of the global loop. Any sub-vertical conductor buried under this in-loop zone will be maximum-coupled and will generate a secondary electromagnetic field detectable by a receiver device. This invention includes the possibility of using a combination a several pairs of loops.

Abstract: A locator capable of tracking buried, non-metallic utility lines (fiber optic, gas, water, waste, conduits) using ground penetrating radar (GPR) and an inertial position sensor is described. In some embodiments, a tracking filter is applied to a hyperbolic trajectory model based on the radar range data to determine a predicted track of the target utility line. After comparison of the predicted track to the measured inertial position, the centerline variance of the tracked line can be deduced. In some embodiments, an electromagnetic pipe and cable locator may also be included. Some embodiments of the invention can include accurate depth calibration and line depth tracking. Further, a display may provide results to a user in a simplified fashion.

Abstract: A method for locating an object buried in soil in which at least one electromagnetic signal is imparted onto the buried object, thereby generating an electromagnetic field around the buried object. The electromagnetic field as well as at least one electromagnetic property of the soil surrounding the buried object, such as moisture content, temperature and density, is then determined. Data related to the at least one electromagnetic property is transmitted to a data processor in which at least one algorithm is applied to the data, whereby a location of the buried object is determined.

Abstract: A method for identifying a buried metal object using a three-dimensional steerable magnetic field (3DSMF) system. The method comprises generating a magnetic field vector (MFV) at a first MFV position above the buried metal object; measuring a time decay response at the first MFV position; generating a MFV at a next MFV position above the buried metal object; measuring a time decay response at the next MFV position; repeating the above steps until a complete 360-degree measurement of time decay responses of the buried metal object is completed; processing all measured time decay responses with a target search algorithm to determine a magnetic polarizability tensor of the buried metal object; and identifying the buried metal object by matching the magnetic polarizability tensor of the buried metal object to a known magnetic polarizability tensor of an object.

Abstract: A device for detecting a prohibited object in a zone with protected access includes a supporting base designed to receive a single foot wearing a shoe of an individual to be inspected. The device further includes a detector to detect a target material and a position-identifier suitable for imposing accurate positioning of the foot of the individual being inspected relative to the detector.

Abstract: A method of and system for locating a single passive underground marker type may distinguish false indications caused by other marker types. In accordance with aspects of the present invention, minimization or elimination of false marker indications may be accomplished by processing the response from a marker to determine which frequency has the largest response.

Abstract: A metal detector having a plurality of phase delay discrimination regions with corresponding selectable exception spaces therein.

Abstract: Tracking a boring tool is performed within an underground region using a locating signal. The boring tool is moved through the ground during a series of distance movements such that potential movement of the boring tool during any one of the distance movements is less than a maximum movement value. A current positional relationship is determined for a current one of the distance movements based on: a last-determined positional relationship established for an immediately preceding one of the distance movements, certain orientation parameters, the maximum movement value and the determined signal strength of the locating signal in the current positional relationship. Target coordinates are accepted and a target position, based on the target coordinates, is included as part of the current positional relationship. The position of the target is unconstrained with respect to system geometry. Steering command features are provided along with steering warnings.

Abstract: A surface tracker includes a tubular marker body having an interior electronic marker and a visual indicator attached to an upper end of the marker body which extends away from the marker body. When deployed, the marker body is mostly underground and the visual indictor extends upwardly from the ground level to provide above-ground visual recognition. The visual indicator may be a plurality of resilient filaments which pass through a hole in a tab portion of the marker body at the upper end thereof, the filaments being folded about the tab portion and secured to the tab portion using a heat-shrink tube. The visual indication, along with the ability to electronically detect the marker, provides a tracker with superior locating capability.

Abstract: A metal detection system with a magnetometer head coupleable to conventional footware and method of use for facilitating hands-free detection of metals below a surface of the ground adjacent to a user. The metal detection system with a magnetometer head coupleable to conventional footware and method of use includes a magnetometer assembly, a control assembly, and a coupling assembly. The magnetometer assembly is designed for passing over a surface and detecting metal below the surface. The control assembly is operationally coupled to the magnetometer assembly, and facilitates operational control of the magnetometer assembly. The coupling assembly operationally couples the magnetometer assembly to a piece of conventional footware.

Abstract: A metal detector capable of operating in both a time-domain mode and a frequency-domain mode includes a transmitter component and a receiver component. The transmitter component includes a transmitter coil that can receive both an AC and DC current source for frequency-and time-domain operation respectively. The AC signal is impressed on the DC signal such that while the transmitter coil is charging, frequency-domain sensing is occurring and when the transmitter coil is switched off, time-domain sensing is occurring. The receiver component uses a primary field bucking method to ensure that both time-and frequency-domain modes can operate with the receiver coil.

Abstract: A system and method for locating a horizontal bore below a ground surface includes a transmitting source configured to radiate from the bore a dipole magnetic field aligned with the bore. A receiver is located remote from the transmitting source and has a first coil and a second coil. Each coil defines an axis, wherein the axes of the first coil and the second coil are orthogonal to each other. A measurement device is in communication with the coils and configured to measure the phase of signals induced on the coils by the magnetic field when the axis of the first coil is horizontally perpendicular to the axis of the magnetic field and the axis of the second coil is vertically perpendicular to the axis of the magnetic field. The measurement device is also configured to determine the lateral position of the transmitting source relative to the coils responsively to the phase of the signals on the first coil and the second coil.

Abstract: A pulse inductive metal detector that includes a variable resistor for controlling coil characteristics for both transmitter and receiver modes of operation. A coil coupled with an electronic switch is charged with current from the power source in a transmitter mode such that when the electronic switch is abruptly switched closed the coil emits a magnetic field that induces eddy currents in a metal target. Once the transmitter magnetic fields have decayed enough, the coil can be operated in a receiver mode to detect a magnetic field resulting from eddy currents in the metal target. The variable resistor is coupled across the coil for varying the resistance across the coil to optimize the pulse inductive metal detector sensitivity to the metal target.

Abstract: A boring tool is moved through the ground in a region which includes at least one electrically conductive in-ground line and which is subject to static magnetic fields including the magnetic field of the earth.

Abstract: A new digital architecture for metallic pipe and cable locators, providing accurate estimation of the fundamental locate parameters, electromagnetic signal strength and signal direction, and utilizing a nested Digital Phase-Locked Loop (DPLL) structure is disclosed. The obstacles to signal direction measurement in low SINR environments using the signal select method are overcome and a more precise phase comparison between the carrier and the FM modulation signals is obtained. The architecture further significantly reduces analog front-end hardware requirements, offers wider resistance to component tolerances, lower calibration and test time, and provides flexible frequency selectivity. Locators according to the present invention provide accurate estimation of the fundamental physical parameters of line location (electromagnetic signal strength and signal direction) in extremely noisy environments, using Digital Signal Processing (DSP) methods.

Abstract: An above ground locator includes an apparatus for determining the strength of the locating signal at a selected point relative to the boring tool. The apparatus includes an antenna arrangement configured for measuring the strength of the locating signal at the selected point along first and second orthogonally opposed receiving axes to produce first and second received signals. A phase shifting arrangement phase shifts the first and second received signals in a predetermined way to generate first and second phase shifted signals, respectively. Thereafter, a summing arrangement adds the first and second phase shifted received signals to generate an output signal which is a vector sum of the first and second received signals. In one feature, third and fourth signals derived from the first and second signals are used to eliminate balance point ambiguity which is present using the first and second signals alone.

Abstract: When cables run side by side over a longer distance, an alternating-current signal used for cable location can couple or ‘bleedover’ to neighboring cables. The coupled current flowing in the neighboring cable creates field distortion and makes position determination of the targeted cable difficult. The resulting magnetic field of both (or more) cables has a non-circular shape and is commonly known as a distorted field. Established methods for finding the position of the cable under investigation lead to inaccuracies or even wrong locates. The method described herein eliminates the field distortion that is due to the coupled cables by demodulating a phase reference signal placed on the cable by a transmitter into two signal strength constituents. The inphase signal represents the field strength of the targeted conductor and is substantially free of field distortion. The other quadrature signal contains the component of the field associated with distortion.

Abstract: A method is disclosed for locating a receiver in a borehole having a conductive liner by inducing an electromagnetic field from a transmitter in a first borehole, detecting at a first location by at least one receiver located in a second borehole having a conductive liner, a first electromagnetic field induced by the transmitter, detecting at a second location by the at least one receiver, a second electromagnetic field induced by the transmitter and calculating a set of geometry coordinates for the first location based on the first electromagnetic field and the second electromagnetic field.

Abstract: A method of inspecting a conduit and a conduit inspection device are disclosed. The method relates to producing a primary magnetic field to induce a current in the conduit so that the currents produce a decaying secondary magnetic field influenced by the conduit. The secondary magnetic field is analysed by time domain analysis to provide an indication of the state of the conduit. The device which produces the primary magnetic field can be moved relative to the conduit so that the secondary magnetic field is detected at different positions along the conduit so that the state of the conduit at various positions along the conduit can be determined. The device for producing the primary magnetic field comprises a transmitter having at least one winding and a detector for detecting the secondary magnetic field comprising at least one inductor coil. A storage is provided for storing the data detected by the inductor coil and is coupled to the conductor coil by a communication link.

Abstract: A magnetic anomaly homing system and method utilize an array of four triaxial magnetometer (TM) sensors coupled to a non-magnetic platform. The four TM sensors are positioned at the vertices of a rectangular parallelogram. The magnetic field sensed at the four TM sensors is processed to generate complete gradient tensors and corresponding scalar gradient contractions thereof for four two-axis gradiometers formed by the array. The scalar gradient contractions define guidance control parameters used to steer the platform toward the magnetic anomaly.

Abstract: A system and method use magnetic field sensing to detect underground objects for strike avoidance. The system detects magnetic field components for both passive distortions in the magnetic field indicative of a ferromagnetic object and active magnetic fields that are impressed on an object by a signal generator. A detection module has a magnetic sensor assembly that detects the magnetic field components. The magnetic field component data is transferred through a multiplexer to an analog/digital converter to a processor. Pitch angle data from a pitch sensor and roll angle data from a roll sensor also may be transferred to the processor. The data is processed by the processor to determine the orientation of the detection module with respect to the object. The detection module may be installed in an underground boring tool or a trenching assembly.

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.

Abstract: A stud finder for a light generating device, having a surface and a connection structure on the surface to removably mount either a light generating device or a leveling device thereto.

Abstract: A portable area monitoring system for use with a horizontal directional drilling machine and adapted to produce a composite of the positions of a beacon and a fixed object. In a preferred embodiment the sensor assembly is supported by a hand-held frame and adapted to detect signals emanating from each of a beacon and a fixed object. The sensor assembly transmits the detected signals to a processor which simultaneously processes the signals to produce a composite of relative positions of the beacon and the fixed object to the frame. The composite of the relative positions of the beacon and the fixed object to the frame is communicated to the operator using a portable display.