Patent Description:
The evolving complexity of infrastructure often requires precise location and identification of utility lines (e.g., underground power lines, gas lines, phone lines, fiber optic cable conduits, cable television (CATV) cables, sprinkler control wiring, water pipes, sewer pipes, etc.) for purposes of repair, enhancement, and/or replacement. Such utility lines, collectively and individually referred to herein as "buried objects" or "buried utilities," may be buried in the ground and/or otherwise hidden from normal sight. Construction and/or excavation operations typically require the locations and/or identification of such utility lines be known so as to avoid costly and hazardous destruction of infrastructure (for example, so that a buried natural gas line is not ruptured during excavation of the ground for work on other utilities).

In utility locating operations (also denoted as "locates" for brevity), one or more locating devices, also referred to herein as "buried utility locators," "utility locators," or simply "locators" for brevity, may be carried and moved about a locate area to detect, process, and/or record magnetic field signals for use in determining information associated with the utilities and/or other conductors in the ground. For example, one or more locators may be moved over the ground or other surface by an operator, with each locator receiving magnetic field signals emitted from one or more utilities. In one or more processing elements of the locator, the magnetic field signals are then processed to determine information about the buried utility, such as its position relative to the ground surface, depth, type of utility, geographical location, and the like.

If the buried utilities are conductors that carry their own alternating current electrical signal, they can be traced by detecting emitted magnetic field signals at their correspondingly energized frequency or frequencies, such as <NUM> or <NUM>, or harmonics thereof, from underground power cables. This is commonly known as "passive locating" (i.e., detecting magnetic field signals emitted from currents flowing in a utility due to a signal applied to the utility, as in the case of an electrical power signal, or induced in the utility from electromagnetic radiation from power lines, radio transmitters, or other signal sources).

Signals may also be coupled to the utility by a user during a locate operation. These signals have a predefined frequency or frequencies, and may be generated in a device known in the field as a locate transmitter or "transmitter" for short. The output of the transmitter may be directly, inductively, or capacitively coupled to the utility to induce current flow therein. This type of locating is commonly known as "active locating.

In addition, in some locating operations, a device known as a sonde, which includes a magnetic dipole antenna and signal generation module, commonly powered by a battery, is inserted into a pipe, conduit, or other cavity and generates a dipole magnetic field signal that can be detected by the locator. Some locate operations use two or more of these locating techniques at a time, while others rely on a single emitted signal to determine buried utility information. Portable utility locators typically include one or more antennas that are used to detect the magnetic field signals emitted by buried pipes and cables and/or by sondes that have been inserted into pipes.

In addition to the above magnetic field signals, some underground utility installations use marker devices placed adjacent to the utilities. Such marker devices are typically passive markers including a single resonant circuit for operating in a resonance mode responsive to a signal transmitting electromagnetic energy at a specific frequency, which is expected to be re-transmitted at the same frequency for detection of such marker devices. These marker devices lack control over the received electromagnetic energy, which is often affected by its form factor, component construction, manufacturing tolerances, underground environment (e.g., wet or otherwise conductive soil) where the marker devices are placed, etc. This can negatively affect performance of such marker devices and result in an output signal (re-transmitted signal) having a gradually decayed amplitude often undetectable by a receiver (e.g., locator antenna) or detectable, occasionally, with a limited signal range requiring close coupling with the receiver. Further, re-transmission of electromagnetic energy, from the marker device to the receiver, at the same frequency or nearly same frequency of the received signal results in backscattering of the re-transmitted electromagnetic energy at the receiver, resulting in substantial interference making detection of the marker device difficult and/or erroneous. Additional and expensive devices/components are often required for an attempt to reduce backscattering.

Accordingly, there is a need in the art to address the above-described as well as other problems related to marker devices and associated locating systems.

<CIT> describes an integrated buried utility locator system, including a locator including a marker device excitation transmitter, a buried utility locator along with one or more marker devices. In operation a marker device excitation signal is sent from the locator at least partially simultaneously to receiving and processing a buried utility signal.

This disclosure relates generally to apparatus, systems, and methods for locating hidden or buried objects. For example, in one aspect, the disclosure relates to apparatus, systems, and methods for locating buried utilities in conjunction with associated buried utility marker devices (hereinafter referred as "marker devices" or "markers" for brevity).

The invention relates to marker devices. The marker devices include a marker device antenna and an electronic circuit coupled to the marker device antenna. The electronic circuit includes two resonant circuits, a first resonant circuit and a second resonant circuit. The first resonant circuit may include resonant/tuning elements such as capacitors, which in combination with the marker device antenna forms the first resonant circuit. At the first resonant circuit, an excitation signal at a first frequency is received from a marker excitation device. The received excitation signal In is converted into a power supply by a power circuit for powering the electronic circuit. Once powered, a processing element and associated electronics in the electronic circuity generate an output signal responsive to the received excitation signal. This output signal is received by the second resonant circuit for tuning the output signal and/or providing the tuned output signal to the marker device antenna. The tuned output signal has an improved signal strength (e.g., higher amplitude than the generated output signal) enabling efficient and accurate detection of the marker device at a receiver end (e.g., at utility locator) with improved signal range.

The marker devices described herein may be configured in a variety of different shapes and form factors according to different embodiments of the subject matter.

The marker devices comprise one or more housings for enclosing and sealing the marker device antenna and the electronic circuit from ingress of environmental solid and liquid contaminants upon underground burial and for minimizing detuning of the marker device in a predetermined environment, the housings shaped in a toroidal shape, or a pipe sleeve shape comprising an interior sleeve onto which the device antenna is wound and an outer sleeve fixed about the interior sleeve, wherein a printed circuit board, PCB, containing the electronic circuit, is located between the interior sleeve and the outer sleeve.

The marker devices may be buried in proximity to buried utilities or may be disposed on or within the buried utilities to mark such utilities. The marker devices may, thereafter, be used in conjunction with a utility locator (e.g., handheld utility locator or vehicle-mounted utility locator) and a marker excitation device to locate marked buried utilities. The marker excitation devices described herein may be attached to the utility locator, integrated into the utility locator, or provided as a standalone device in various embodiments.

These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used for limiting the scope of the claimed subject matter.

The present disclosure may be more fully appreciated in connection with the following detailed description taken in conjunction with the accompanying drawings, wherein:.

This disclosure relates generally to apparatus, systems, and methods for locating hidden or buried objects using marker devices. For example, in one aspect, the disclosure relates to apparatus, systems, and methods for locating buried utilities in conjunction with associated electromagnetic marker devices.

Details of the locating devices referred herein, additional components, methods, and configurations that may be used in conjunction with the embodiments described subsequently herein in further embodiments are disclosed in co-assigned patent applications and patents including <CIT>, entitled OMNIDIRECTIONAL SONDE AND LINE LOCATOR; <CIT>, entitled A BURIED OBJECT LOCATING AND TRACING METHOD AND SYSTEM EMPLOYING PRINCIPAL COMPONENTS ANALYSIS FOR BLIND SIGNAL DETECTION; <CIT>, entitled SONDES FOR LOCATING UNDERGROUND PIPES AND CONDUITS; <CIT>, entitled COMPACT SELF-TUNED ELECTRICAL RESONATOR FOR BURIED OBJECT LOCATOR APPLICATIONS; <CIT>, entitled INDUCTIVE CLAMP FOR APPLYING SIGNAL TO BURIED UTILITIES; <CIT>, entitled LOCATOR WITH APPARENT DEPTH INDICATION; <CIT>, entitled MULTI-SENSOR MAPPING OMNIDIRECTIONAL SONDE AND LINE LOCATORS; <CIT>, entitled COMPACT LINE ILLUMINATOR FOR LOCATING BURIED PIPES AND CABLES; <CIT>, entitled SINGLE AND MULTI-TRACE OMNIDIRECTIONAL SONDE AND LINE LOCATORS AND TRANSMITTER USED THEREWITH; <CIT>, entitled MULTI-SENSOR MAPPING OMNIDIRECTIONAL SONDE AND LINE LOCATORS AND TRANSMITTER USED THEREWITH; <CIT>, entitled ADAPTIVE MULTICHANNEL LOCATOR SYSTEM FOR MULTIPLE PROXIMITY DETECTION; <CIT>, entitled PORTABLE LOCATOR SYSTEM WITH JAMMING REDUCTION; <CIT>, entitled SMART PERSONAL COMMUNICATION DEVICES AS USER INTERFACES; <CIT>, entitled AN UNDERGROUND UTILITY LOCATOR WITH A TRANSMITTER, A PAIR OF UPWARDLY OPENING POCKETS AND HELICAL COIL TYPE ELECTRICAL CORDS; <CIT>, entitled PRE-AMPLIFIER AND MIXER CIRCUITRY FOR A LOCATOR ANTENNA; <CIT>, entitled HIGH-Q SELF TUNING LOCATING TRANSMITTER; <CIT>, entitled RECONFIGURABLE PORTABLE LOCATOR EMPLOYING MULTIPLE SENSOR ARRAY HAVING FLEXIBLE NESTED ORTHOGONAL ANTENNAS; <CIT>, entitled BURIED OBJECT LOCATOR SYSTEM EMPLOYING AUTOMATED VIRTUAL DEPTH EVENT DETECTION AND SIGNALING; <CIT>, entitled SYSTEMS AND METHODS FOR LOCATING BURIED OR HIDDEN OBJECTS USING SHEET CURRENT FLOW MODELS; <CIT>, entitled SYSTEM AND METHOD FOR LOCATING BURIED PIPES AND CABLES WITH A MAN PORTABLE LOCATORAND A TRANSMITTER IN A MESH NETWORK; <CIT>, entitled QUAD-GRADIENT COILS FOR USE IN LOCATING SYSTEMS; <CIT>, entitled MULTI-FREQUENCY LOCATING SYSTEMS AND METHODS; <CIT>, entitled SMART PAINT STICK DEVICES AND METHODS; <CIT>, entitled DOCKABLE TRIPODAL CAMERA CONTROL UNIT; <CIT>, entitled DUAL SENSED LOCATING SYSTEMS AND METHODS; <CIT>, entitled LOCATOR ANTENNA WITH CONDUCTIVE BOBBIN; <CIT>, entitled DUAL ANTENNA SYSTEMS WITH VARIABLE POLARIZATION; <CIT>, entitled OMNI-INDUCER TRANSMITTING DEVICES AND METHODS; <CIT>, entitled OPTICAL ROUND TRACKING APPARATUS, SYSTEMS AND METHODS; <CIT>, entitled USER INTERFACES FOR UTILITY LOCATORS; <CIT>, entitled SONDE DEVICES INCLUDING A SECTIONAL FERRITE CORE STRUCTURE; <CIT>, entitled WEARABLE MAGNETIC FIELD UTILITY LOCATOR SYSTEM WITH SOUND FIELD GENERATION; <CIT>, entitled PIPE MAPPING SYSTEM; <CIT>, entitled Locator and Transmitter Calibration System; <CIT>, entitled UTILITY LOCATOR TRANSMITTER DEVICES, SYSTEMS, AND METHODS WITH DOCKABLE APPARATUS; <CIT>, entitled UTILITY LOCATING SYSTEMS WITH MOBILE BASE STATION; <CIT>, entitled INDUCTIVE CLAMP DEVICES, SYSTEMS, AND METHODS; <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS; <CIT>, entitled NULLED-SIGNAL LOCATING DEVICES, SYSTEMS, AND METHODS; <CIT>, entitled ECONOMICAL MAGNETIC LOCATOR APPARATUS AND METHOD; <CIT>, entitled GROUND TRACKING APPARATUS, SYSTEMS, AND METHODS; <CIT>, entitled GROUND-TRACKING DEVICES AND METHODS FOR USE WITH A UTILITY LOCATOR; <CIT>, entitled MARKING PAINT APPLICATOR FOR USE WITH PORTABLE UTILITY LOCATOR; <CIT>, entitled GROUND-TRACKING DEVICES FOR USE WITH A MAPPING LOCATOR; <CIT>, entitled HAPTIC DIRECTIONAL FEEDBACK HANDLES FOR LOCATION DEVICES; <CIT>, entitled METHODS AND SYSTEMS FOR SEAMLESS TRANSITIONING IN INTERACTIVE MAPPING SYSTEMS; <CIT>, entitled MARKING PAINT APPLICATOR FOR PORTABLE LOCATOR; <CIT>, entitled SIGNAL KEYING UTILITY LOCATING DEVICES, SYSTEMS, AND METHODS; <CIT>, entitled BURIED OBJECT LOCATOR APPARATUS AND SYSTEMS; <CIT>, entitled UTILITY LOCATING SYSTEMS, DEVICES, AND METHODS USING RADIO BROADCAST SIGNALS; <CIT>, entitled SELF-STANDING MULTI-LEG ATTACHMENT DEVICES FOR USE WITH UTILITY LOCATORS; <CIT>, entitled BURIED UTILITY MARKER DEVICES, SYSTEMS, AND METHODS; <CIT>, entitled UTILITY LOCATOR SUPPORT STRUCTURES; <CIT>, entitled SYSTEMS AND METHODS FOR LOCATING AND/OR MAPPING BURIED UTILITIES USING VEHICLE MOUNTED LOCATING DEVICES; <CIT>, entitled OPTICAL GROUND TRACKING APPARATUS, SYSTEMS, AND METHODS; <CIT>, entitled TRACKABLE DIPOLE DEVICES, METHODS, AND SYSTEMS FOR USE WITH MARKING PAINT STICKS; <CIT>, entitled SYSTEMS AND METHODS FOR UNIQUELY IDENTIFYING BURIED UTILITIES IN A MULTI-UTILITY ENVIRONMENT; <CIT>, entitled GROUND-TRACKING SYSTEMS AND APPARATUS; <CIT>, entitled LOCATING DEVICES, SYSTEMS, AND METHODS USING FREQUENCY SUITES FOR UTILITY DETECTION; <CIT>, entitled PHASE-SYNCHRONIZED BURIED OBJECT TRANSMITTER AND LOCATOR METHODS AND APPARATUS; <CIT>, entitled PHASE SYNCHRONIZED BURIED OBJECT LOCATOR APPARATUS, SYSTEMS, AND METHODS; and <CIT>, entitled IMAGE-BASED MAPPING LOCATING SYSTEM. The above patents and applications may be collectively denoted herein as the "co-assigned applications".

As used herein, the terms "buried objects," "buried utility assets," "buried utilities," "utilities," and "utility lines" include objects located inside walls, between floors in multi-story buildings or cast into concrete slabs, for example, as well as objects disposed below the surface of the ground. In a typical application a buried object is a pipe, cable, conduit, wire, or other object buried under the ground surface, at a depth of from a few centimeters to meters or more, that a user, such as a utility company employee, construction company employee, homeowner, or others want to locate, map (e.g., by surface position as defined by latitude/longitude or other surface coordinates, and/or also by depth), and/or provide a surface mark of using paint, electronic marking techniques, or other identification or mapping techniques. Some non-conductive objects may have associated tracer wires or other conductors buried with them to facilitate electromagnetic locating.

In the context of the present disclosure, the term "position" refers to a location in space which is represented in the form of an absolute position, such as GPS positional coordinates (e.g., Latitude and Longitude), and/or relative position, such as position of a magnetic compass needle relative to an object/location (e.g., buried utility, marker device, landmark, etc.). Further, the term "position" as used herein in association with the marker device(s), buried utilities, and/or other objects includes an orientation (e.g., tilt, rotation, compass needle orientation etc.), depth, and/or elevation of such objects with respect to a reference (e.g., locator, electronic marker device, landmark, ground surface, sea level, etc.). Furthermore, the term "position" may also include other parameters indicative of position/location of such objects typically represented in a three-dimensional (X, Y, Z coordinates or their equivalent) space.

The following exemplary embodiments are provided for the purpose of illustrating examples of various aspects, details, and functions of the present disclosure; however, the described embodiments are not intended to be in any way limiting. It will be apparent to one of ordinary skill in the art that various aspects may be implemented in other embodiments within the scope of the present disclosure as defined by the appended claims. As used herein, the term, "exemplary" means "serving as an example, instance, or illustration. " Any aspect, detail, function, implementation, and/or embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects and/or embodiments.

In one aspect, the disclosure relates to marker devices which may be placed below a ground surface in proximity to buried utilities or on or within the buried utilities. Such marker devices may be energized or excited, at particular times (e.g., during locate operations), using an above-ground marker excitation device to assist in locating corresponding buried utilities. In the case of a plurality of marker devices, the marker devices may be energized simultaneously, sequentially, or selectively based on received signal strength/frequency of the excitation signal, etc. The marker devices include a marker device antenna for receiving the excitation signal from the above ground excitation device at an excitation signal frequency, and for sending, in response to the excitation signal, a reply or output signal at an output signal frequency, which may be substantially different from the excitation signal frequency. An above ground marker excitation device as disclosed herein may be a standalone marker excitation device, a marker excitation device coupled to a utility locator (e.g., a handheld utility locator or a vehicle-mounted utility locator), or a marker excitation device integrated into the utility locator.

In another example not forming part of the invention, the disclosure relates to marker devices which may be used in conjunction with locating system and methods. Such locating systems and methods may include various locator devices and associated apparatus for determining information regarding utility lines and other locate environment data (e.g., presence or absence of a buried utility line, type of utility, depth in the ground, and the like). The systems and methods disclosed herein may, for instance, include one or more utility locators (e.g., handheld utility locators, vehicle-mounted utility locators, or integrated locators for both sending excitation signals and receiving output signals), transmitter devices, base stations, pipe sondes, and so on. Further details of some such devices and apparatus that may be included in the systems herein are described in the various patents and patent applications referenced above.

In another example not forming part of the invention, the disclosure relates to marker device(s) used in conjunction with locating systems and mapping systems for identifying and recording the location of buried utilities. For instance, the position of marker devices and position of corresponding utilities may be added to a database corresponding to geographical location from one or more position sensors or systems (e.g., a satellite positioning system module (e.g., GPS module, Galileo system module, GLONASS module, or other satellite-based positioning system module), inertial based positioning system, optical positioning system, or other as described in various patents and patent applications above) integrated or associated with the locator. Information stored in the database may be accessed to create various maps for assisting users in locating the utilities.

The disclosure relates to marker device(s), which include an electronic circuit responsible for signal handling (e.g., processing of received excitation signals from and generating output signal provided to the antenna). The electronic circuit includes dual resonant circuits and optionally other circuitries or elements, such as processing elements, memories, and/or other components for carrying out instructions. For instance, such components may be used to communicate information (e.g., position information, utility type, serial number, or other information) from marker devices through signal modulation (e.g., amplitude signal keying (ASK), phase signal keying (PSK), frequency signal keying (FSK), or the like). The electronic circuit may further include a control circuit for selectively enabling or disabling power circuit or other circuit elements depending on various parameters including, but not limited to, signal strength/frequency, and type of information/data to be communicated. Also, the electronic circuit may include timing circuits which may be used in conjunction with control circuit for timer based control of the power circuits or other circuit elements. In some embodiments, the electronic circuit may also include one or more tuning elements (e.g., small value capacitors) controlled and/or adjusted automatically by the control circuit for auto-tuning of the marker device.

In an example not forming part of the invention, the disclosure relates to methods of identifying marker devices and corresponding information using the utility locator and associated positioning system(s), device(s) and/or technique(s). In such methods, positional information (e.g., position, depth, etc.) of a marker device may be detected by a utility locator configured with positioning systems (e.g., GPS or other satellite navigation systems, inertial navigation systems, optical positioning systems, etc.). The detected information may be used to access database containing pre-stored information regarding the marker device and associated utility line or other buried asset in proximity of which the marker device is placed, to obtain the associated utility line information (e.g., position of the utility line, type of the utility line, serial number, characteristics and other information pertaining to the utility line therefrom. For instance, utility type, serial number, and/or other information may be included in the database corresponding to a marker device at a position in space. When the locator detects the presence of a marker device at that location, the database information may be accessed to retrieve information pertaining to corresponding utility line.

In an example not forming part of the invention, the disclosure relates to a high quality factor (referred to herein as high Q) marker devices including an insulating jacket encapsulating a marker device antenna and electronic circuit therein. The insulating jacket may have a predefined thickness (e.g., a thickness of approximately twice the diameter of a marker device antenna conductive core or larger) to provide a physical distance between the marker device antenna/the electronic circuit and the soil or other environment in which the marker device may be buried. The insulating jacket and the physical distance created therefrom may reduce capacitive coupling of signals (at both loading of received excitation signal and broadcasting of output signal) with the soil or other conductive elements in the soil, thereby reduce detuning of the marker device. The insulating jacket may be made of materials having a low dielectric constant properties (e.g., polypropylene (<NUM> - <NUM>), polyethylene (<NUM>), polystyrene (<NUM> - <NUM>), polytetrafluoroethylene (<NUM>), or other materials having a similarly low dielectric constant number). The insulating jacket of the various embodiments described herein may further protect sensitive electronics and materials from corrosive and otherwise damaging elements in the soil or locate environments.

In another aspect, the disclosure relates to marker device(s) designed in the shape of a toroid or a loop. Such loop shaped marker device includes a marker device antenna and an electronic circuit, which may be included on a printed circuit board (PCB) in the loop shaped marker device. The marker device antenna may have one or more turns, each of which may be individually encapsulated by an insulating jacket.

In an example not forming part of the invention, the disclosure relates to a plurality of marker devices which may be strung along or placed at predefined or random intervals in the utility line or in proximity to a utility line or other buried assets. Such marker devices may be energized either simultaneously or individually, or the marker devices, in certain examples, may be selectively enabled or energized depending upon various parameters including signal strength/frequency of the excitation signal received from the marker excitation device.

In an example not forming part of the invention, the disclosure relates to marker device(s) generating the output signal in multiple different frequencies depending upon various parameters, such as kind of data to be communicated (e.g., serial number, data defining position of the marker device, and the like). Further, the marker device(s) may be selectively programmed to enable or disable different circuit elements in the marker device(s) depending upon usage, function, and/or operating status, etc. of such elements, to save power.

In another example, not forming part of the invention, the marker device is designed as a ground-stake. The ground-stake marker device may include an outer insulating jacket and/or other outer shell shaped like a nail or ground-stake allowing a user to readily push, hammer, or otherwise place the marker device into the ground. The ground-stake shaped insulating jacket may encapsulate a marker device antenna, which is a loopstick antenna in this example, comprising a series of conductive windings wrapped about a ferrite core. The windings of the loopstick antenna may connect electrically to an electronic circuit responsible for signal handling (e.g., processing of received excitation signals from and generating output signal provided to the antenna). The electronic circuit may include transceiver circuitry and may additionally include other circuitries. The electronic circuit may be included on a printed circuit board (PCB). A ground-stake marker placement tool is disclosed to assist a user in placing the ground-stake marker device into the ground. The ground-stake placement tool may include a vertical mast with a handle on the proximal end held by a user and a stake retaining structure about its distal end. The stake retaining structure may be configured to allow a ground-stake marker device to be released upon action of the user (e.g., turn of the handle, press of a button, or the like).

In one of the aspect of the invention, the marker device is a pipe sleeve marker device. A pipe sleeve marker device may be shaped to be seated about a pipe or other utility line such that the utility line may pass through the marker device. Such a pipe sleeve marker device may include interior and exterior insulating layers with a number of turns of conductive windings or other conductive element and at least one connected electronic circuit positioned in between. The interior and exterior insulating layer may, for instance, be tube shaped and sized to seat about the exterior of a length of pipe. Interior and exterior insulating layers may be comprised of dielectric materials (e.g., polypropylene (<NUM> - <NUM>), polyethylene (<NUM>), polystyrene (<NUM> - <NUM>), polytetrafluoroethylene (<NUM>), or other materials having a similarly low dielectric constant number) further dimensioned to reduce capacitive coupling of signals to either conductive elements in the surrounding soil or other environment as well as environment or substance flowing within the pipe or utility line. Such embodiments may also use or be comprised of polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or other non-conductive pipe materials. Some embodiments may use materials with a higher dielectric constant. In some embodiments, pipe sleeve marker devices may be used as fittings in securing together separate lengths of pipe or other utility lines.

In an example not forming part of the invention, the marker device is embedded in a pipe typically made of a non-conductive material (e.g., plastic). Such a marker device embedded pipe may include an interior pipe length onto which a number of turns of conductive windings or other conductive element and at least one connected electronic circuit may be seated. An exterior pipe length may be extruded or otherwise fixed to the outside of the interior pipe length, securing wire turns and electronic circuit or circuitries in between. Interior and exterior pipe lengths may be comprised of dielectric materials (e.g., polypropylene (<NUM> - <NUM>), polyethylene (<NUM>), polystyrene (<NUM> - <NUM>), polytetrafluoroethylene (<NUM>), or other materials having a similarly low dielectric constant number) further dimensioned to reduce capacitive coupling of signals to either conductive elements in the surrounding soil or other environment as well as environment or substance flowing within the marker device embedded pipe. Various antenna configurations and orientations may be used in pipe sleeve marker device embodiments and/or marker device embedded pipe embodiments.

In an example not forming part of the invention, the marker device is built onto a printed circuit board (PCB). The PCB marker device may include a marker device antenna and an electronic circuit. An overmold layer may encase the PCB, the marker device antenna, and the electronic circuit providing protection from corrosive or damaging external elements as well as provide an insulating layer. The overmold layer may have a predefined or predetermined thickness, for example, a thickness of approximately twice the diameter of a conductive core of the marker device antenna or larger to provide a physical distance between the marker device antenna/electronic circuit and the soil or other environments in which the marker device may be buried. The thickness of the overmold layer, and the physical distance created therefrom, may reduce capacitive coupling of signals (at both loading of received excitation signal and broadcasting of output signal) with the soil or other conductive elements in the soil, thereby reducing detuning of the PCB marker device.

Various additional aspects, features, and functionality are further described below in conjunction with the appended Drawings.

Turning to <FIG>, an example locate system embodiment using a marker device in accordance with aspects of the present disclosure, such as loop marker device embodiment <NUM>, is illustrated. In this example, one or more hidden or buried utilities, such as utility line <NUM>, is buried below the ground surface <NUM>, with loop marker device <NUM> at a defined position in the ground relative to the utility <NUM>. The marker device <NUM> may correspond to a loop marker device <NUM> as illustrated and described in detail with <FIG> or to other marker device embodiments as described subsequently herein or in the applications above. The system and methods associated with <FIG> may further apply and /or share elements and features with the various other marker devices, marker embodiments, and associated electronic circuits described herein (e.g., marker device <NUM> of <FIG>, marker device <NUM> of <FIG>, marker device <NUM> of <FIG>, marker device embedded pipe <NUM> of <FIG>, marker device embedded pipe <NUM> of <FIG>, marker device embedded pipe <NUM> of <FIG> and electronic circuit <NUM> of <FIG>).

The ground surface <NUM> may be of dirt or grass, a roadway, a sidewalk, a building floor, and the like over which the locator is moved during a locate operation. The marker device <NUM> and the various other marker device embodiments disclosed herein may be resonant high quality factor (high "Q") devices optimized to reduce detuning due to capacitive coupling of signals with the marker device's environment. For example, marker device <NUM> and the various marker device embodiments disclosed herein may include a dielectric element encapsulating its marker device antenna, thereby providing a physical distance between the marker device antenna and surrounding environment sufficient to reduce capacitive coupling of signals to the soil or other conductive environments, as well as to further reduce detuning of the marker device. Such a dielectric element may, for example, be a jacket of polypropylene or other insulating material with similar dielectric properties.

The system of <FIG> may further include a utility locator <NUM> carried by a user <NUM> for detecting and measuring magnetic field signals (e.g., signal <NUM> emitted from the buried utility <NUM> and signal <NUM> generated from the loop marker device <NUM>). A marker excitation device <NUM>, which may be an excitation transmitter, may be operatively coupled to the locator <NUM>, to generate and send an excitation signal <NUM> to the loop marker device <NUM>. The marker excitation device <NUM> may include an excitation device antenna, which may have different orientations according to various embodiments of the subject matter.

For example, as shown in <FIG>, the excitation device antenna may be designed in the shape of a loop oriented in a vertical orientation (e.g., excitation device antenna <NUM> of <FIG>). In this orientation, the loop shaped excitation device antenna may achieve a better signal coupling with the loop marker device when the loop shaped marker excitation device is at one of the possible offset positions which break the orthogonality between the vertically positioned loop shaped excitation device and the horizontally placed loop marker device buried below the ground surface <NUM>. In some examples, the orientation of excitation device antenna may be horizontal (e.g., excitation device antenna <NUM> of <FIG>). The horizontal orientation of the loop shaped excitation device may have a better signal coupling with the loop marker device and minimal or no signal interference. In other implementations, the orientation of the excitation device antenna may be angularly adjustable (e.g., adjustable excitation device antenna <NUM> of <FIG>).

The excitation signal <NUM> generated by the marker excitation device <NUM> may be a continuous or pulsed RF signal for energizing or "pinging" marker device <NUM>. Marker device <NUM> may include an electronic circuit for receiving the excitation signal <NUM>, extracting energy, such as in the form of DC power converted from the excitation signal to generate a power supply to power itself, such as when tuned to the frequency of the excitation signal <NUM>, and then to further generate and send an output magnetic field signal <NUM> for detection by the locator via the marker device antenna. Output signal <NUM>, when detected and processed by the locator <NUM>, may be used to indicate the presence of a marker device <NUM> to the locator <NUM> and, in some implementations, may also provide data stored in the marker device <NUM>, and/or access data regarding the marker device and associated utility at the corresponding location.

In an exemplary embodiment, the frequency of output signal <NUM> may be generated by dividing down the excitation signal <NUM> frequency. For example, the excitation signal <NUM> may be divided down by a predefined value, such <NUM> (or other divisors), to generate the output signal <NUM>. For example, if the input signal is at <NUM>,<NUM>,<NUM>, the output signal would then be <NUM>,<NUM>. Other frequencies and divide ratios may alternately be used in various embodiments based on particular operating environments, regulatory constraints, device constraints (e.g., power reduction, etc.), signal loss, and the like.

The output signal <NUM> may be tuned to have an improved signal strength (e.g., high amplitude than the generated output signal) enabling efficient and accurate detection of the marker device with improved signal range (e.g., <NUM> meters or more). Further, the output signal <NUM> may be generated in multiple different frequencies depending upon various parameters including the type of data to be communicated. For example, the output signal may be generated at first frequency for communicating a serial number, and at a second frequency for communicating data defining position of the marker device, and the like.

The locators may detect magnetic field signals <NUM> emitted from buried utility <NUM> to locate the utility line <NUM> using locating methods/functionality as described in the various applications above with respect to locators and their configuration and operation. For example, signal <NUM> emitted from utility line <NUM> may be inherently generated from the line (e.g., due to normal current flow in a conductor, such as in a buried power line). Alternately, or in addition, current flow may result from the electromagnetic coupling of one or more radiated signals (e.g., broadcast radio signals) to the utility line, and/or current flow may optionally be induced or directly coupled to utility line <NUM> through use of a transmitter device and associated clamp, inductive coupler, and the like (not shown).

The transmitter may generate and output a current signal for coupling to one or more utilities at a desired frequency or frequencies with a predefined waveform or waveforms. Details of embodiments of such transmitter devices, couplers, and other associated elements and methods of passive and active magnetic signal generation and coupling to underground utility lines are disclosed in the applications above.

Signals <NUM>, associated with utility <NUM>, may be detected by the utility locator <NUM> using one or more locator antenna coils and/or antenna coils arrays (typically in the form of two or more antenna arrays, such as antenna arrays including omnidirectional and/or gradient antenna coils, dodecahedron antenna arrays, and/or other polyhedron or general antenna arrays such as are described in the applications above). The received signal <NUM> may be processed by one or more processing elements in the locator to determine information associated with the buried utility <NUM> such as its depth, location (relative to the ground surface <NUM>), current flow in the utility, presence of other utilities or conductive objects, and the like.

In other locate operations and system embodiments, such as in embodiments where the utility line is of a non-conductive material (e.g., plastic pipes, etc.), signals may not be coupleable from a transmitter device, other signal generating device, or other signal source, and current may not flow inherently therein. In such operations, marker devices, such as marker device <NUM>, may be placed near the utility line during installation or later to assist in locating the utility's position in the ground, without the need for traditional locating via emitted magnetic field signals from the utilities (some non-conductive utilities use conductor tracer wires or other conductors - the marker device embodiments herein may be used in conjunction with traditional locating of these utilities or in place of traditional locating).

A marker device embodiment such as marker device <NUM> of <FIG> and/or other embodiments described subsequently herein, may utilize the method embodiment <NUM> as illustrated in <FIG>. This method may be used after placement of the marker device to store marker placement measurements corresponding to the location of the marker device and or associated utility line for subsequent locate operations. The placement of the marker device will typically be underground near or on or within a utility line or other utility asset(s) to be marked for assistance in subsequent locate operations. Placement may occur during installation of a utility line, pipeline surveys, and/or during other excavation or construction operations.

Method embodiment <NUM> may include step <NUM> where the marker device is placed in a target position, such as near the utility line and below the ground. This positioning may be identified exactly at the time of placement, may be captured via an image, GPS receiver, and/or other placement identification mechanisms, or the marker may merely be put in adjacent to the utility (e.g., placed or thrown in a hole by an installer). In a second step <NUM>, a set of marker placement measurements of the marker device may be determined. Marker placement measurements may include position (e.g., latitude/longitude and/or other like absolute position measurements, orientation/tilt, or relative positional data) and depth in the ground of the marker device or the associated utility line. The marker placement measurements may further include other locate information including, but not limited to, utility type marked, size, color, imagery of the install, and so on.

These measurements may be determined through various devices and systems including, for example, a locator, surveying systems and devices, satellite navigation systems and sensors (e.g., GPS, GLONASS, etc.), cameras, and the like, and/or by physical measurements (e.g. tape measurements) after placement of the marker device and before its burial. In one embodiment, measurements may be taken using a laser-based measurement device(s)/elements (e.g., LiDAR, radar, sonar, laser tape measuring device, laser tagging device, laser rangefinder, etc.), which may either be integrated into the utility locator and/or marker excitation device, or may be provided as a separate device coupled to or used in conjunction with the utility locator and/or marker excitation device.

One exemplary embodiment for measurement is illustrated in <FIG>. As shown, a marker measurement device <NUM> integrated into a locator <NUM> includes a laser element emitting a laser beam <NUM>, which may be pointed towards the center of the marker device <NUM> for taking measurements. Measurements may be taken in several ways which would be apparent to a person skilled in the art. The measurement device <NUM> may include additional elements such as imaging elements (e.g., cameras) for capturing images of placed marker devices, and other elements that may assist in positioning the laser and/or accurately taking measurements. Additional measurements for the marker devices may also be performed using other devices including, but not limited to, the locator <NUM>, at the same time or subsequently. The locator <NUM> may also take measurements (e.g., position, depth, etc.) and/or images or video of the buried utility being marked with an attached or separate camera, as well as measurements and/or images/video of other nearby utilities or objects (e.g., underground objects, such as traceable tape, sonde, and the like, and/or above-ground objects, such as landmarks, sidewalks, and the like). A microphone and associated audio recording device may be used to record an annotation of the placements in conjunction with the above-described information. The microphone and recorder may be integral with or separate from the locator <NUM>.

In step <NUM>, information/measurements from step <NUM> may be stored in a non-transitory memory or database, which may either be an internal memory of the locator or an external memory/remotely located memory communicatively coupled to the locator. Such information may be accessible to utility locators and may be utilized for subsequent locate operations performed at the same location. Locators in subsequent locate operations may access stored marker placement measurements and/or other locate information based on position/location (e.g., from satellite navigation or other position systems and sensors), images, or other information associated with a detected marker device.

Turning to <FIG>, method embodiment <NUM> illustrates details of locating a marker device at the locator and accessing stored marker placement measurements and/or other locate information. With method <NUM>, one or more marker devices may be assumed to be already placed, typically in the ground near a utility line or other utility asset, and may have corresponding marker placement measurements as described in, for example, method <NUM> of <FIG> and/or other locate information for each marker device. Such marker placement measurements and other locate information may be accessed by the locator. For example, a database containing such measurements and information may be on the locator and/or accessed remotely through other connected system devices (e.g., smart phone, laptop computer, base station, or the like).

Method <NUM> may include step <NUM> where an excitation signal is broadcasted from a marker excitation device, which may be integral with or separate from the locator. The broadcasted excitation signal is received at the marker device via a marker device antenna, and, in response to the received excitation signal, a corresponding output signal may be generated by the marker device. This output signal is then broadcast by the marker device via the marker device antenna. In step <NUM>, the output signal may be received at the locator. In step <NUM>, a current position of the locator may be determined via positioning systems and sensors (e.g., from a GPS or other satellite or terrestrial positioning system signal, inertial positioning elements, and the like). In step <NUM>, marker placement measurements and other locate information may be accessed based on marker device detected at step <NUM> and corresponding location determined at step <NUM>.

In other marker device embodiments, marker devices may use signal modulation (e.g., encoded via amplitude signal keying, phase signal keying, or other signal keying scheme) to communicate various related information (e.g., utility type, latitude and longitude coordinates or other position information, depth of the marked utility, serial number, tilt and/or orientation of the marker device within the ground, measured underground parameters such as temperature, soil moisture, soil conductivity, chemical information, and the like) in the marker device output signal. Signals may be sent on multiple frequencies with different data types and/or modulations used for different frequencies in some embodiments. Example embodiments may include circuitry such as is described in <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS.

In some locate operations and system embodiments, marker device excitation signals may be generated by a separate marker excitation device. For instance, a stand-alone marker excitation device of <FIG>, an accessory marker excitation device of <FIG>, an integrated excitation device of <FIG>, and/or a vehicle-mounted excitation device of <FIG> may be used to generate excitation signals to one or more marker devices in various implementations.

As illustrated in <FIG>, a standalone marker excitation device embodiment <NUM> may have a vertically oriented excitation device antenna embodiment <NUM>, having a predetermined effective area, so as to provide range of excitation signals transmitted therefrom to reach marker devices in the ground. The excitation device antenna <NUM> of <FIG> may, for example, be a coil antenna, though alternative embodiments having other shapes, configurations, types, quantities, and orientations of antenna elements may be used. A mast <NUM> may extend vertically above the excitation device antenna <NUM> to a connected battery <NUM> and handle <NUM>. Battery <NUM> may be operatively coupled to provide electrical power to signal generating circuitry (not shown in <FIG>) further connected to the excitation device antenna <NUM> and concealed within mast <NUM>. The handle <NUM> may allow the marker excitation device <NUM> to more readily be carried by a user. The stand-alone marker excitation device <NUM> may include controls to perform functions described herein (e.g., on/off switch, frequency or frequencies selection, and so on) not specifically illustrated in <FIG>.

In other embodiments, the marker excitation device <NUM> may have a horizontally oriented excitation device antenna <NUM> (as shown in <FIG>), or angularly adjustable excitation device antenna <NUM> and/or angularly adjustable mast <NUM> (as shown in <FIG>).

Turning to <FIG>, an accessory or attachment marker excitation device <NUM> may be mechanically and/or operatively coupled to and function through controls of a locator <NUM>. Accessory marker excitation device <NUM> may have an excitation device antenna <NUM> of sufficient effective area to provide range in excitation signals generated therefrom to reach marker devices in the ground. The excitation device antenna <NUM> of <FIG> may be a coil antenna. In alternative embodiments other shapes, configurations, quantities, and orientations of excitation device antennas may be used. A mast <NUM> may extend vertically above the excitation device antenna <NUM>. A wire connector <NUM> may electrically connect accessory marker excitation device <NUM> (and excitation device antenna <NUM> and internal signal generating circuitry, not shown) to locator <NUM>.

Power to marker excitation device <NUM> may be provided from a power supply, such as a battery, of the locator <NUM>. In alternative embodiments, power may be provided additionally or solely by one or more batteries included on the marker excitation device. Furthermore locator <NUM> may be configured to control aspects of marker excitation device <NUM> operation as described herein (e.g., power on/off, frequency or frequencies to be transmitted, and the like) by wired or wireless means via one or more wireless communications modules (e.g., Bluetooth, Wifi modules, cellular data connections, and the like). In some embodiments, such controls may alternatively be located on the marker excitation device <NUM>.

One or more brackets <NUM> may be located along mast <NUM> allowing the marker excitation device <NUM> to mechanically secure to the locator <NUM>. The brackets may be configured to release and allow the marker excitation device <NUM> to be disconnected and removed from locator <NUM> when desired, such as for transport or storage. Although the excitation device antenna <NUM> has been illustrated as vertically oriented in <FIG>, it is to be understood that the excitation device antenna <NUM> attached to the locator <NUM> may have other orientations, such as a horizontal orientation or an angularly adjustable orientation (e.g., as described above with respect to standalone marker excitation device).

Turning to <FIG>, a marker excitation device may be integrated in a locator <NUM>. In this integrated embodiment, the excitation device antenna and other associated elements may be configured in the form of a ring <NUM> mounted, for example, inside the lower antenna node <NUM> of the locator <NUM>. In other embodiments the marker excitation device may be placed in other positions on or in the locator <NUM>. Examples of a locator with integrated marker excitation device are described in detail in applications, such as in <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS.

Turning to <FIG>, in some system implementations, a marker excitation device embodiment may be mounted on or in a vehicle, and may be operatively coupled to one or more vehicle-mounted utility locators. For example, in some utility locating and mapping operations, one or more utility locators may be secured to a vehicle for detecting presence of buried utilities and identifying data pertaining to the buried utilities. Examples are described in <CIT>, entitled SYSTEMS AND METHODS FOR LOCATING AND/OR MAPPING BURIED UTILITIES USING VEHICLE-MOUNTED LOCATING DEVICES. In such systems, a marker excitation device may be added thereto to transmit a signal or signals, thereby exciting marker devices as well as inducing signal onto buried utility lines for the purpose of locating and mapping utility lines and associated marker devices which are buried in the ground.

As illustrated in <FIG>, a vehicle mounted locating system <NUM> may include the utility locators <NUM> secured to a mounting fixture <NUM>. The mounting fixture <NUM> may further be secured to a vehicle <NUM>, for example, in an exemplary embodiment via a trailer hitch on vehicle <NUM>. Electrical power may be transmitted to various electronics on the vehicle mounted locating system <NUM> via trailer hitch wiring (not illustrated in <FIG>). Such powered electronic components of the vehicle mounted locating system <NUM> may include signal processing and or generating circuitry, powering of GPS <NUM> and/or other included electronics, and additional brake lights on mounting fixture <NUM> (not illustrated), and the like.

The GPS system <NUM> may include real time kinematics (RTK) for determining or refining position corresponding to the locating data acquired by utility locators <NUM> and mapping of utility lines such as utility lines <NUM> and <NUM> as well as any marker devices, such as marker device <NUM>. In some embodiments, signals emitted by utility lines may be actively or passively induced onto the utility line. As illustrated in <FIG>, an active signal or signals may be induced into utility lines <NUM> and/or <NUM> via a marker excitation device <NUM>. The marker excitation device <NUM> may further be adjustable at other angles along direction arrow <NUM>, as well as be secured and stowed upright in a vertical position. In other embodiments, one or more marker excitation devices may be used with a vehicle mounted locating system that may be secured to the vehicle mounted locating system and/or the vehicle itself in various different orientations.

Turning to <FIG>, an exemplary marker device embodiment <NUM> is illustrated. Marker device <NUM> may include an insulating jacket <NUM> enclosing a marker device antenna <NUM>, and a cover element <NUM> enclosing the electronic circuit <NUM>. The insulating jacket <NUM> and the cover element <NUM>, described herein, may be collectively referred to as "housings," or may be individually referred to as "housing. " In some embodiments, a combined/common housing (not shown) may be used for enclosing both the marker device antenna <NUM> and the electronic circuit <NUM>. Embodiment <NUM> is in the exemplary form of a circular loop; however, other embodiments may include alternate shapes (e.g., ovals, rectangular/square shapes, etc.).

In the context of the present subject matter, the term "housing" may include any kind of enclosure/casing, cover, coating, etc., to cover or protect the marker device and associated antenna, components, circuits, or elements. The housings <NUM>, <NUM> are used to insulate the marker device antenna and the electronic circuit from the underground environment to seal it from ingress of water or other fluids, and also provide a protective covering to reduce damage to the marker device antenna and/or the electronic circuit due to impact of objects under the ground, cutting tools, and the like. The housing <NUM>, i.e., the insulating jacket, may further be used to protect the marker device antenna <NUM> from detuning by selecting appropriate materials. For example, in an exemplary embodiment, the housings <NUM>, <NUM> may include a dielectric layer of polypropylene or other materials having a similar dielectric constant to provide a predefined capacitance between the marker device antenna/the electric circuit and the ground. Example materials with similar dielectric constants to polypropylene may include, but are not limited to, polyethylene (<NUM>), polystyrene (<NUM> - <NUM>), polytetrafluoroethylene (<NUM>), or other similar materials. Materials of higher dielectric constant may be used in alternate embodiments, and in embodiments where insulation is not necessary (e.g., in placements within walls or other spaces where the marker is surrounded by air), material of other dielectric constants may alternately be used.

As shown in <FIG>, the marker device antenna <NUM> may include an outer conductor or conductive cover or coating of copper or a copper alloy (or other high conductivity materials such as silver, gold, etc.) to enclose or cover a structural core made of steel or other structural materials to maintain shape and provide rigidity. The copper and steel may be copper-clad steel or other conductive material disposed over a structural material. In some embodiments, both the outer cover and the core of the antenna <NUM> may be made of copper-clad steel or other conductive materials. In some embodiments the conductor may be pure copper, copper alloys, or other high conductivity materials without separate structural internals.

In an exemplary embodiment, the marker device antenna <NUM> may be shaped as a loop antenna comprising a single individually insulated antenna coil (single turn). Alternate embodiments may include multiple turns. The multiple turns may be wound adjacent or over each other or, in alternate embodiments may be helically wound.

In structural core embodiments, the mechanical strength of the steel (or other structural materials adjacent the conductor) in the copper-clad steel antenna <NUM> may aid in maintaining the desired shape of marker device antenna <NUM> and overall marker device <NUM> while minimizing impedance at high operating frequencies due to the well known skin effect of current flow. A printed circuit board (PCB) <NUM>, as shown in <FIG>, contains the electronic circuit components and traces. The PCB may be coupled electrically about either end of the coil of marker device antenna <NUM> as shown in <FIG>.

As illustrated in the <FIG>, the marker device <NUM> may be toroidal in shape, thereby maximizing effective antenna area given a particular length of marker device antenna <NUM>. The specific diameter of the marker device <NUM> and other loop antenna embodiments described herein may be selected to provide a desired range needed to receive signals from a locator or other marker excitation device, as well as to transmit signals of sufficient power level to a locator. For example, in underground marking applications, a marker device, such as marker device <NUM>, may a circular loop shape of approximately <NUM> to <NUM> in diameter. As noted previously, in alternative embodiments, loop antennas may be formed into shapes other than a toroid. The dimensions of such non-toroidal shaped marker device antennas may be adjusted to provide appropriate aperture and range in signals as required by a particular application and installation environment.

Turning to <FIG>, the marker device antenna <NUM>, which may comprise copper-clad steel, may have an outer conductor <NUM> surrounding a structural core of steel <NUM>. The insulating jacket <NUM> encapsulating the marker device antenna <NUM> may be of a predetermined thickness, given the dielectric constant of selected jacket materials, to reduce capacitive coupling of signals to conductive soil or other surrounding environment and further detuning of the marker device <NUM> to a desired amount. The thickness of the jacket may be determined based on various factors/parameters, including but not restricted to, frequencies being utilized. Insulating jacket <NUM> and cover element <NUM> may further protect against corrosive or other damaging elements of the soil or other environment in which marker device <NUM> is placed. In an exemplary embodiment, the dielectric material jacketing the marker device antenna may be of a thickness of approximately twice the diameter of the antenna conductor or larger. For example, the insulating jacket <NUM> may be of <NUM>/<NUM> to <NUM>/<NUM> inch (<NUM> inch = <NUM>) polypropylene encapsulating an antenna <NUM> of <NUM> to <NUM> gauge copper-clad steel.

The electronic circuit, when coupled with the marker device antenna, such as the loop antenna or loopstick antenna configurations or other antennas described herein, may include circuitry for receiving excitation signals from the marker device antenna or antenna(s), processing and powering the marker device from received excitation signals, and generating corresponding output signals and applying the output signal to the marker device antenna(s).

<FIG> illustrates an exemplary transceiver circuitry embodiment in accordance with various aspects. The transceiver circuitry <NUM> of <FIG> may correspond with the transceiver circuitry of marker device <NUM> of <FIG>, marker device <NUM> of <FIG>, marker device <NUM> of <FIG>, marker device <NUM> of <FIG>, marker device <NUM> of <FIG>, marker device embedded pipe <NUM> of <FIG>, marker device embedded pipe <NUM> of <FIG>, and/or marker device embedded pipe <NUM> of <FIG> as described herein, or of other marker devices in accordance with the present disclosure. Further, the marker device antenna <NUM> of <FIG> may correspond to the loop antenna <NUM> of <FIG>, the multi-loop antenna <NUM> of <FIG>, the marker device <NUM> of <FIG>, loopstick-type antenna <NUM> of <FIG>, conductive windings <NUM> of <FIG>, conductive windings <NUM> of <FIG>, conductive windings <NUM> of <FIG>, antenna <NUM> of <FIG>, and/or other antenna configurations.

Turning to <FIG>, a block diagram of an exemplary marker device embodiment is illustrated. As shown, the marker device <NUM> may include a marker device antenna <NUM>, an electronic circuit <NUM>, and an insulating jacket <NUM> encapsulating the marker device antenna <NUM> and the electronic circuit <NUM> therein. The insulating jacket <NUM> may include a dielectric layer for reducing capacitive coupling to the ground or other environment in which the marker device is embedded. The dielectric layer may have a thickness of about twice the diameter of a conductive core of the marker device antenna or larger. The dielectric layer may be made of materials, such as polypropylene, polyethylene, polystyrene, polytetrafluoroethylene, or a combination thereof. The marker device antenna <NUM> may be a loop antenna comprising a single turn or a plurality of turns, which may be helically wound about a form. Further, the marker device antenna <NUM> may include a conductive core made of a copper or copper alloy encapsulating a structural core made of steel or other structural materials.

The electronic circuit <NUM>, which is responsible for signal handling (i.e., processing of received excitation signals from and generating output signal provided to the antenna and related functions) may include a power circuit <NUM>, an output circuit <NUM>, one or more processing elements <NUM>, memories <NUM>, and other circuitries or components <NUM> for carrying out instructions. Such components may be used to communicate information (e.g., position information, utility type, serial number, or other information) from marker devices through signal modulation (e.g., amplitude signal keying, phase signal keying, frequency signal keying, or the like).

In operation, the marker device antenna <NUM> receives an excitation signal at a first frequency from a marker excitation device. The received excitation signal is converted by the power circuit <NUM> into a power supply for powering the electronic circuit. The signal is then processed by one or more processing elements <NUM> to generate an output signal, at a second frequency different from the first frequency. This output signal is received by an output circuit <NUM> for providing an output signal to the marker device antenna <NUM>. In some embodiments, the processing elements <NUM> may generate the output signal at a plurality of frequencies based on various parameters including type of data to be communicated (e.g., serial number, data defining position of the marker devices, etc.). The processing element(s) <NUM> may include, for example, a microcontroller or other programmable elements having programmed instructions to generate a modulated output signal (e.g., modulated using ASK, PSK, FSK, etc.) to send data (e.g., serial number of the marker device, data defining a position of the marker device, etc.).

The electronic circuit <NUM> may further include a control circuit <NUM> for selectively enabling or disabling different circuits or circuit elements in the electronic circuit <NUM> based on, for example, signal strength/frequency of the excitation signal, duty cycle, coding, type of information/data to be communicated, usage of such elements, their function, operating status, etc., to save power. The electronic circuit <NUM> may also include one or more tuning elements (e.g., capacitors) controlled and/or adjusted automatically by the control circuit <NUM> for auto-tuning of the marker device <NUM>. Further, the electronic circuit <NUM> may include a timing circuit <NUM> that may be used in conjunction with control circuit <NUM> for timer based control of the power circuits <NUM> or other circuit elements of the electronic circuit <NUM>.

<FIG> illustrates an exemplary electronic circuit embodiment of the marker device. As shown, the electronic circuit <NUM> may connect electrically to the marker device antenna <NUM> and may include transceiver circuitry <NUM> and/or other circuitries for signal handling such as powering marker device <NUM>, processing of received excitation signals <NUM> from the marker device antenna <NUM>, and generating output signal <NUM> further provided to the marker device antenna <NUM>. The electronic circuit components may, in some embodiments, be included on a PCB, such as the PCB <NUM> of <FIG>. Marker device <NUM> and the electronic circuit may be used in the embodiments as described and illustrated in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>. As shown in <FIG>, an excitation signal <NUM>, which may correspond to signals <NUM> of <FIG> and/or other excitation signals described herein, may be received at the marker device antenna <NUM> at a first frequency.

Excitation signal <NUM> received at the marker device antenna <NUM> may form a first resonant circuit containing a marker device antenna <NUM> (L1), main capacitor <NUM> (C1) and a series of small value capacitors <NUM> (C2 - Cz). In some embodiments, the first resonant circuit, including all tuning elements, i.e., capacitors (e.g., main capacitor <NUM> (C1) and small value capacitors <NUM> (C2 - Cz)), may originally be set to below the resonant frequency and, during tuning, small value capacitors <NUM> (C2 - Cz) may be removed one at a time until proper tuning of the marker device <NUM> is achieved.

Such a tuning method is further described in method embodiment <NUM> of <FIG>. The transceiver circuitry <NUM> may further include a power circuit/supply <NUM> having a diode D1 and capacitor C/O. The diode D1 may have low forward drop and low capacitance attributes. An LED <NUM> may further be included on power circuit <NUM> used to both protect against overloading and diminishing the quality factor of resonant circuits in the transceiver circuitry <NUM> of marker device as well as to be used as a visual indicator during tuning as described subsequently in method <NUM> of <FIG>.

The transceiver circuitry <NUM> may further include a divide down circuit/element <NUM> and output circuit/element <NUM>. The divide down circuit <NUM> may include capacitor CH and a frequency divider configured to divide the excitation signal <NUM> by integer n. The divided down signal may be provided to the output circuit <NUM>. The output circuit <NUM> may be a second resonant circuit having inductor L2 and capacitors C12 and C13. Resonating of output circuit <NUM> (interchangeably referred to as a 'second resonant circuit') at divided down signal from the divide down element <NUM> may send resonant current to the marker device antenna <NUM> (L1). Marker device <NUM> may thereby transmit output signal <NUM> at a lower frequency where output frequency <NUM> is a product of dividing down the excitation signal <NUM> by integer n. For example, integer n may be a predefined value, such as <NUM>, to generate output signal <NUM> where output signal <NUM> is equal to excitation frequency divided by n. Where n is predefined as <NUM> and the input signal is at, for example, <NUM>,<NUM>,<NUM>, the output signal would then be <NUM>,<NUM>. Other frequencies and divide ratios may be used in various embodiments.

It is to be understood that the power circuit <NUM>, the output circuit <NUM>, and the divide down circuit <NUM> disclosed herein corresponds to the power circuit <NUM>, the output circuit <NUM>, and the divide down circuit <NUM>, of <FIG>, respectively.

In other marker device embodiments in accordance with aspects of the present disclosure, processing elements, non-transitory memories, and/or other components for carrying out instructions may be included in the electronic circuit. For instance, such components may be used to communicate information (e.g., position information, utility type, serial number, or other information) from marker devices through signal modulation techniques (e.g., ASK, PSK, FSK, or the like). Examples of such circuitry are described in <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS. In some embodiments, signal modulation may be selectively enabled or disabled in the circuitry based on the signal strength. For example, when the signal strength is below a predefined value, signal modulation in the circuitry may remain turned off. After signal strength reaches a predefined value, signal modulation functionality may be triggered automatically, thereby allowing signal modulation to occur.

Tuning of a marker device embodiment with transceiver circuitry such as is described with respect to <FIG> may be implemented using a method embodiment such as embodiment <NUM> of <FIG>. Method <NUM> may include a step <NUM> in which the desired excitation frequency is determined. For instance, the desired excitation frequency may be <NUM>,<NUM>,<NUM>. In step <NUM>, the offset resolution of small value capacitors is determined. For example, the small value capacitors, such as the small value capacitors <NUM> as described in <FIG>, may ha be chosen to control the tuned/resonant frequency by approximately <NUM>,<NUM> each. In step <NUM>, an offset excitation tuning frequency is determined based on excitation frequency of step <NUM> and the small value capacitor values of step <NUM> (e.g., desired excitation frequency minus small value capacitor value).

For example, given the desired excitation frequency of <NUM>,<NUM>,<NUM> and small value capacitors whose value influence the tuned frequency by approximately <NUM>,<NUM>, the offset excitation tuning frequency selected at step <NUM> will be <NUM>,<NUM>,<NUM>. In step <NUM>, small value capacitors (e.g., small value capacitor <NUM> of <FIG>) may be removed one at a time until the LED dims, thereby indicating that the marker device is now properly tuned. Once tuned, the marker device may be placed for use.

In accordance with certain aspects of the present disclosure, an alternate loop antenna marker device embodiment may include multiple turns of antenna coils. For example, maker device embodiment <NUM> illustrated in <FIG> may share elements of marker device <NUM> illustrated in <FIG> with the exception of having multiple coil turns <NUM> and <NUM>. Marked device embodiment <NUM> illustrated in <FIG> likewise has multiple turns of antenna element <NUM>, as shown in <FIG>. Each coil turn <NUM> and <NUM> (of <FIG>) or the multiple turns of antenna element <NUM> may be turns of the same conductive antenna element insulated with an insulating jacket or, in alternate configurations, may include multiple housings or other configurations.

For example, the marker device embodiment <NUM>, as shown in partial detail in <FIG>, may include an insulating jacket or cover <NUM> enclosing the multiple turns of the marker device antenna <NUM>. The jacket <NUM> may be used to insulate the marker device antenna from the underground environment and seal the antenna element from the ingress of water or other fluids as described elsewhere herein. The jacket <NUM> may also provide a protective covering to reduce physical damage to the marker device antenna <NUM> due to impact of surrounding objects and/or environment under the ground.

The jacket <NUM> may operate as a dielectric material between the marker device antenna <NUM> and the ground, and may prevent detuning of the marker device antenna <NUM>. For example, the insulating jacket <NUM> may be made of polypropylene or other materials having a similar dielectric constant as of polypropylene (e.g., polyethylene having about <NUM> dielectric constant, polystyrene having about <NUM>-<NUM> dielectric constant, polytetrafluoroethylene having about <NUM> dielectric constant, etc.) to provide a predefined capacitance between the marker device antenna <NUM> and the ground. Other housing embodiments as described elsewhere herein may also be used.

The marker device antenna <NUM> may be comprised of copper-clad steel, as illustrated in <FIG>, having an outer conductor <NUM> surrounding a structural core of steel <NUM>. Other conductor/structural embodiments as described herein may also be used. The insulating jacket <NUM> encapsulating the marker device antenna may have a predetermined thickness, given the dielectric constant of jacket materials, to reduce capacitive coupling of signals to conductive soil or other surrounding environment and further detuning of the marker device <NUM> (<FIG>) to a desired amount.

Referring back to <FIG>, a cover element <NUM> encapsulating internal electronics, in combination with the insulating jacket <NUM>, may be included to protect against corrosive or other damaging elements of the soil or other environments in which marker device <NUM> is placed. In an exemplary embodiment, the dielectric material jacketing the marker device antenna may be of a thickness of approximately twice the diameter of the antenna conductor or larger. In marker device <NUM>, the insulating jacket <NUM> may be of <NUM>/<NUM> to <NUM>/<NUM> inch (<NUM> inch = <NUM>) polypropylene encapsulating the multiple turns of the marker device antenna <NUM> of <NUM> to <NUM> gauge copper-clad steel.

As further illustrated in <FIG>, the cover element <NUM> may encapsulate an antenna connector <NUM> providing an electrical pathway between the end of one turn of the marker device antenna <NUM> and the opposite end of the other turn of the marker device antenna <NUM> as well as a series of terminal connector pieces <NUM> connecting and providing electric pathways between the unconnected ends of each turn of the marker device antenna <NUM> and a PCB <NUM>. The PCB <NUM> may include the transceiver circuitry processing of received excitation signals, powering, and generating output signals to the marker device antenna <NUM>. The transceiver circuitry may correspond to that described with respect to <FIG> or other marker devices disclosed in <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS or as known or developed in the art. A PCB cover <NUM> may cover PCB <NUM> to protect circuitry therein during the manufacturing process and further aid in protecting the PCB <NUM> circuitry from corrosive or damaging external elements when in use.

The loop antenna marker device embodiments disclosed herein, such as marker device <NUM> of <FIG> and marker device <NUM> of <FIG> and marker device <NUM> of <FIG>, may be placed on or near utility lines or other buried assets. In some embodiments, such marker devices may be physically connected together along one or more lengths of rope, tape, cordage, or other associated materials and placed on or near the target utility. In some embodiments the marker devices may be attached or coupled to the utility, such as being embedded in a pipe or tubular utility, or attached to a tape or other material buried adjacent to the utility.

For example, as illustrated in <FIG>, a marker tape embodiment <NUM> may include a plurality of such loop antenna marker devices <NUM> secured to and spaced apart along a tape-shaped structure or housing <NUM>. The marker device <NUM> may be of the variety of marker devices <NUM> of <FIG>. Tape <NUM>, containing multiple loop antenna marker devices <NUM>, may be rolled out on or near the length of a utility <NUM> or other buried asset. In such device embodiments and systems thereof, a user <NUM> equipped with an integrated buried utility locator <NUM>, in which the excitation device antenna and associated circuitry may be contained or integrated in the utility locator or may be separate in some embodiments, may send an excitation signal <NUM>, which may be received at one or more of the marker devices <NUM> on marker tape <NUM>. Receiving of excitation signal <NUM> at marker devices <NUM> may power the marker device <NUM> and generate and transmit a corresponding marker device output signal <NUM> which may be received back at the locator and processed as described herein to locate the marker device(s).

In some embodiments, as a user traverses the length of the a marker tape (such as marker tape <NUM> of <FIG>) or other series of marking device embodiments creating a pathway, only the individual marker device (e.g., marker device <NUM> of <FIG>) nearest the excitation signal may become energized and transmit a signal, thereby allowing the user to trace from one individual marking device to the next based on proximity to the excitation signal. In some embodiments, the marker devices may be programmed and sized for a particular application so that only a single marker device will be turned upon when excited by a particular excitation circuit (e.g., by limiting output power, etc., and/or by data received from the excitation device or by other methods).

Turning to <FIG> and <FIG>, ground-stake marker device example <NUM> is illustrated. Marker device <NUM> may include an insulating jacket <NUM> encapsulating, as shown in <FIG>, a marker device antenna, which is a loopstick antenna <NUM> in this example. Marker device <NUM> may include a PCB <NUM> with electronics, a PCB connector <NUM>, and a dampening piece <NUM>. The electronics may include marker device circuitry as described elsewhere herein and in the applications above. The ground stake marker device housing may be shaped in the form of a stake as shown in <FIG> with a spike end, a head end for pushing or pounding, and an elongate middle therebetween.

The insulating jacket <NUM> may be comprised of materials having a low dielectric constant such as described previously herein. For example, such low dielectric constant materials may include polypropylene (<NUM> - <NUM>), polyethylene (<NUM>), polystyrene (<NUM> - <NUM>), polytetrafluoroethylene (<NUM>), or other materials having a similarly low dielectric constant number. The insulating jacket <NUM> of ground-stake marker device <NUM> may be shaped with a point about one end to facilitate ease in being forced or otherwise placed in the ground as further illustrated in <FIG> and in a generally stake-shaped housing structure. In alternative embodiments, other shapes of insulating jackets may be used to aid in marker device placement.

As illustrated in <FIG>, the loopstick antenna <NUM> of ground-stake marker device <NUM> may include a plurality of conductive windings <NUM> (e.g., conductive wire, tape, PCBs, and the like) wrapped or placed about a ferrite rod <NUM>. A PCB <NUM> containing transceiver circuitry may connect electrically to conductive windings <NUM> for processing received excitation signals, powering, and generating output signals to the conductive windings <NUM> of the loopstick antenna <NUM>. Such transceiver circuitry may be of the type as described in <FIG> herein or that of the various marker devices disclosed in <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS, or of other similar electronic circuits as known or developed in the art. A PCB connector <NUM> may be used to secure PCB <NUM> to ferrite rod <NUM>. An optional dampening element <NUM> may be positioned about the top of loopstick antenna <NUM> so as to protect internal components from possible damage inflicted when ground-stake marker device <NUM> is hammered or otherwise forced into the ground.

Turning to <FIG>, one or more ground-stake marker devices <NUM> may be pushed or hammered into the ground surface <NUM> above or near a buried utility <NUM> or other buried asset. In such locating systems, a user <NUM> equipped with an integrated buried utility locator <NUM> may send excitation signal <NUM> received at one or more of the marker devices <NUM>. Receiving of excitation signal <NUM> at marker device <NUM> may power marker device <NUM> and generate and transmit output signal <NUM>.

Turning to <FIG>, a stake placement device embodiment <NUM> may be used to place ground-stake marker device <NUM> into the ground <NUM> generally above a buried utility line <NUM> or other buried asset. As illustrated, stake placement device <NUM> may be held by a user <NUM> with a ground-stake marker device <NUM> secured in its distal end as the user <NUM> provides a downward force to push the ground-stake marker device <NUM> into the ground <NUM>.

As illustrated in <FIG>, the stake placement device <NUM> may include a vertical shaft <NUM> with a handle <NUM> formed on one end. On the end opposite the handle <NUM>, a stake holding structure <NUM> may be formed with a pair of arms <NUM>.

Turning to <FIG>, the arms <NUM> may be shaped to grip a top portion of ground-stake marker device <NUM>. Upon pressing the ground-stake marker device <NUM> in the ground (not shown), a rotation of stake placement device <NUM> in direction <NUM> may allow the ground-stake marker device <NUM> to be freed from the stake placement device <NUM> and left in the ground.

Turning to <FIG>, a locating system embodiment a with a pipe sleeve marker device embodiment <NUM> is illustrated. The pipe sleeve marker device embodiment <NUM> may be fitted about a utility line <NUM>, such as at connections between pipe segment. In various embodiments, the marker device housing may be shaped to conform to a particular outer shape and size of a corresponding pipe or other object. In some embodiments, such a pipe sleeve marker device <NUM> may be used as a fitting in securing together separate sections of a utility line. In alternate embodiments, the pipe sleeve marker device may include ends and internal dimensions shaped to fit over a pipe or other tubular element or other object.

In the locating system embodiment of <FIG>, a user <NUM> is equipped with a buried utility locator <NUM>. An accessory marker excitation device <NUM>, which may correspond to the accessory marker excitation device <NUM> of <FIG>, may be fitted to locator <NUM> for producing excitation signal <NUM>. The pipe sleeve marker device <NUM> may receive the excitation signal <NUM>, be powered and transmit a corresponding output signal <NUM>. The long axis orientation and depth of the pipe or utility line (e.g. utility line <NUM>) may be determined by the magnetic field signal emitted from the pipe sleeve marker device <NUM>.

As illustrated in <FIG>, <FIG>, and <FIG>, the pipe sleeve marker device embodiment <NUM> has an interior sleeve <NUM> onto which one or more turns of conductive windings <NUM> are wound. A PCB <NUM> containing transceiver circuitry may connect electrically to conductive windings <NUM>. The transceiver circuitry may correspond to that described with respect to <FIG> or other marker devices disclosed in <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS, or as known or developed in the art.

An outer sleeve <NUM> is fixed about the interior sleeve <NUM> with conductive windings <NUM> and PCB in between. The interior sleeve <NUM> and outer sleeve <NUM> may be comprised of materials having a low dielectric constant, such as described previously herein. For instance, such low dielectric constant materials may include polypropylene (<NUM> - <NUM>), polyethylene (<NUM>), polystyrene (<NUM> - <NUM>), polytetrafluoroethylene (<NUM>), or other materials having a similarly low dielectric constant number. A pipe sleeve marker device embodiment in accordance with aspects of the present disclosure may also use or be comprised of polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or other non-conductive pipe materials. Some embodiments may use materials with a higher dielectric constant. The thickness of interior sleeve <NUM> and outer sleeve <NUM> may be dimensioned to reduce capacitive coupling of signals to either conductive elements in the surrounding environment as well as the environment within the pipe or utility line. For instance, the thickness of the interior sleeve <NUM> need not be as thick in the pipe sleeve marker device <NUM> where the utility line is used for natural gas versus a utility line used for water, due to the low conductivity of materials flowing within the pipe.

Turning to <FIG>, a marker device embedded pipe or utility <NUM> including marker device electronic circuits and marker device antennas embedded in the pipe or utility is illustrated. In the locating system example illustrated in <FIG>, a user <NUM> is equipped with a buried utility locator <NUM>. An accessory marker excitation device <NUM>, which may correspond to the accessory marker excitation device <NUM> of <FIG> or other embodiments described herein or known or developed in the art, for producing excitation signal <NUM>, may be fitted to locator <NUM>. The marker device embedded pipe <NUM> may receive the excitation signal <NUM> at one or more points, be powered, and transmit corresponding output signals <NUM>.

As illustrated in <FIG>, <FIG>, the marker device embedded pipe example <NUM> may have an interior pipe length <NUM> onto which a plurality of turns of conductive windings <NUM> may be wound. A PCB <NUM> containing transceiver circuitry may connect electrically to conductive windings <NUM>. The transceiver circuitry may be of the type described with respect to <FIG> or other marker devices disclosed in <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS or other electronic circuits as known or developed in the art. An outer pipe length <NUM> may be extruded or otherwise fixed about the interior pipe length <NUM> with conductive windings <NUM> and PCB <NUM> secured in between.

In an example, the interior pipe length <NUM> and outer pipe length <NUM> may comprise materials having a low dielectric constant. For instance, such materials may include polypropylene (<NUM> - <NUM>), polyethylene (<NUM>), polystyrene (<NUM> - <NUM>), polytetrafluoroethylene (<NUM>), or other materials having a similarly low dielectric constant number. Marker device embedded pipe examples may also use or be comprised of polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or other non-conductive pipe materials. Some examples may use materials having a higher dielectric constant.

The thickness of interior pipe length <NUM> and outer pipe length <NUM> may be dimensioned to reduce capacitive coupling of signals to either conductive elements in the surrounding environment as well as the environment within marker device embedded pipe <NUM>. For example, the thickness of the interior pipe length <NUM> need not be as thick in the marker device embedded pipe <NUM> for natural gas pipes as for water or other liquid pipes.

In some embedded pipe and pipe sleeve examples, the wire may not be continuous or operatively coupled throughout the entire embodiment. Instead, embedded pipe and pipe sleeve examples may contain separate circuits having one or more turns of antenna, and each with its own connected transceiver circuitry which may be included on a PCB, flex circuit, and the like. For example, as illustrated in <FIG>, an embedded pipe marker device example <NUM> may have multiple individual, non-connected marker device circuits. Embedded pipe marker device <NUM> may have an interior pipe length <NUM> onto which individual, non-connected turns of conductive windings <NUM> are wound. Each individual, non-connected turn of conductive winding <NUM> may further be electrically connected to a separate PCB <NUM> containing transceiver circuitry as described with respect to <FIG> and <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS, or as known or developed in the art.

An exterior pipe length <NUM> may be extruded or otherwise fixed to outside of the interior pipe length <NUM>, securing conductive windings <NUM> and PCB <NUM> in between. In some examples, an embedded pipe may have multiple marking device distinct circuits where multiple turns of conductive windings may be in each circuit.

In other embedded pipe and pipe sleeve examples, different orientations, shapes, and/or placement locations of marker device antennas may be used. For example, as illustrated in <FIG>, such an embedded pipe marker device <NUM> may have a number of differently oriented marker device antennas <NUM>, each electrically connected to PCB <NUM> containing transceiver circuitry as described with respect to <FIG> and <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS, or other transceivers or other electronic circuits as known or developed in the art. The marker device antennas <NUM> may be rectangular, running on different sides of embedded pipe marker device <NUM> between an interior pipe length <NUM> and an exterior pipe length <NUM>.

Turning to <FIG>, a PCB marker device example <NUM> is illustrated. Marker <NUM> may include a PCB <NUM> on which various marker device components (e.g., marker device antenna, electronic circuit, and the like) are included/mounted. For example, PCB <NUM> of PCB marker device <NUM> may include a marker device antenna <NUM> and an electronic circuit <NUM> secured thereto. The marker device antenna <NUM> may be one or more traces on PCB <NUM> and/or comprise wire or other conductive element secured thereto. The electronic circuit <NUM> may be of the variety described in conjunction with <FIG> and/or that in the <CIT>, entitled ELECTRONIC MARKER DEVICES AND SYSTEMS or other electronic circuits as known or developed in the art.

An overmold layer <NUM> may enclose or encapsulate PCB <NUM>, marker device antenna <NUM>, the electronic circuit <NUM>, and other components therein. The overmold layer <NUM> may at a predetermined thickness sufficient (e.g., twice the diameter of antenna core or larger) to provide a physical distance between the marker device antenna <NUM>/electronic circuit <NUM> and the soil or other environment in which PCB marker device <NUM> is buried or placed, such as to provide physical and/or dielectric isolation. The overmold layer <NUM> illustrated in <FIG> may be comprised of translucent or transparent materials. In other examples, the overmold layer <NUM> may comprise a variety of other materials, including opaque materials. Such overmold layer <NUM> materials may, in general, be non-conductive and have a low dielectric constant, such as rubber or plastic materials, or other materials, having these properties.

The thickness of the overmold layer <NUM>, and the physical distance created therefrom, may be selected to reduce capacitive coupling of signals (at both loading of received excitation signal and broadcasting of output signal) with the soil or other conductive elements in the soil, and thereby reduce detuning of the PCB marker device <NUM>. The overmold layer <NUM> may further protect internal components (e.g. PCB <NUM>, antenna <NUM>, and electronic circuit <NUM>) from corrosive and otherwise damaging elements in the soil or other locate environment.

A series of optional overmold holes <NUM> may be formed through PCB <NUM> allowing materials of the overmold layer <NUM> to seep through during the overmolding process to add to the strength of the mechanical bond of the overmold layer <NUM>. An additional hole <NUM> may optionally be formed through PCB <NUM> and overmold layer <NUM>. In alternative examples, a PCB marker device example may be formed in shapes other than the rectangular shape illustrated herein. For example, a PCB marker device embodiment may be round having a substantially round-shaped PCB and a circular marker device antenna. In some examples, the PCB <NUM> may be a flex circuit or may be comprised of other flexible materials, thereby allowing the PCB marker device to bend and flex. Such examples may further be bonded or glued or otherwise attached to curved or contoured portions of pipes or other objects for use in locating the marker device and associated pipes or other objects.

In some configurations, the apparatus, circuit, modules, or systems described herein may include means for implementing features or providing functions described herein related to integrated locators, marker devices, marker device excitation transceivers, and related devices, components, methods, and systems. In one aspect, the aforementioned means may be a module comprising a processing element including a processor or processors, associated memory and/or other electronics in which embodiments of the invention reside, such as to implement signal reception, signal processing, switching, signal transmission, or other functions to process and/or condition transmitter outputs, locator inputs, filter received signals, and/or provide other electronic functions described herein. These may be, for example, modules or apparatus residing in buried object integrated locators, marker devices, marker device marker excitation devices or receiver devices, and/or other related equipment, devices, or systems.

In one or more exemplary embodiments, the electronic functions, methods and processes described herein and associated with buried utility marker devices, locators, transmitters, and associated elements may be implemented in hardware, software, firmware, or any combination thereof. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.

As used herein, computer program products comprising computer-readable media including all forms of computer-readable medium except, to the extent that such media is deemed to be non-statutory, transitory propagating signals.

It is understood that the specific order or hierarchy of steps or stages in the processes and methods disclosed herein are examples of exemplary approaches.

Those of skill in the art would understand that information and signals, such as video and/or audio signals or data, control signals, or other signals or data may be represented using any of a variety of different technologies and techniques.

Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the invention as defined by the appended claims.

The various illustrative functions and circuits described in connection with the embodiments disclosed herein may be implemented or performed in one or more processing elements with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, memory devices, and/or any combination thereof designed to perform the functions described herein. In various configurations, a processing element may include one or more processors and one or more operatively coupled processor-readable non-tangible memories wherein instructions to generate the methods, processes, functions, or circuits described herein are stored in the non-tangible memories and read from the memories for execution by the one or more processors. The processing elements may include additional components operatively coupled to the processor(s) such as analog to digital converters, timers, clocks, input-output circuits, communication modules, and/or other electronic devices as are known or developed in the art to receive, process, and/or send analog or digital signals.

Claim 1:
A buried utility marker device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), comprising:
a marker device antenna (<NUM>); and
an electronic circuit (<NUM>) operatively coupled to the marker device antenna, the electronic circuit including:
a first resonant circuit formed with the marker device antenna for receiving an excitation signal at a first frequency from a marker excitation device;
a power circuit (<NUM>) for converting the excitation signal to a power supply for powering the electronic circuit;
a processing element (<NUM>) for generating an output signal responsive to the excitation signal; and
a second resonant circuit (<NUM>) for providing the output signal to the marker device antenna, wherein the output signal is generated at a second frequency different from the first frequency,
the device being characterized by comprising one or more housings (<NUM>) for enclosing and sealing the marker device antenna and the electronic circuit from ingress of environmental solid and liquid contaminants upon underground burial and for minimizing detuning of the marker device in a predetermined environment, the housings shaped in a toroidal shape, or a pipe sleeve shape comprising an interior sleeve onto which the device antenna is wound and an outer sleeve fixed about the interior sleeve, wherein a printed circuit board, PCB, containing the electronic circuit, is located between the interior sleeve and the outer sleeve.