US20040168358A1 - Underground utility detection system - Google Patents

Abstract

Systems for locating an underground utility include means for generating detection data representative of an underground utility within a subsurface of the earth. Systems may also include means for generating geographic positioning data representative of a geographic position of the underground utility and means for storing the geographic positioning data and the detection data. Means are provided for associating the geographic positioning data with the detection data to generate location data representative of a location of the underground utility within the subsurface.

Description

FIELD OF THE INVENTION
• The present invention relates generally to the field of excavation and, more particularly, to systems for acquiring subsurface detection data and positioning data, and for generating data representative of underground utilities, such as underground utility mapping data.[0001]
BACKGROUND OF THE INVENTION
• Various types of excavators have been developed to excavate a predetermined site or route in accordance with a particular manner of excavation. One particular type of excavator, often referred to as a track trencher, is typically utilized when excavating long continuous trenches for purposes of installing and subsequently burying various types of pipelines and utility conduits. A land developer or contractor may wish to excavate several miles or even hundreds of miles of terrain having varying types of unknown subsurface geology.[0002]
• Generally, such a contractor will perform a limited surrey of a predetermined excavation site in order to assess the nature of the terrain, and the size or length of the terrain to be excavated. One or more core samples may be analyzed along a predetermined excavation route to better assess the type of soil to be excavated. Based on various types of qualitative and quantitative information, a contractor will generally prepare a cost budget that forecasts the financial resources needed to complete the excavation project. A fixed cost bid is often presented by such a contractor when bidding on an excavation contract.[0003]
• It can be appreciated that insufficient, inaccurate, or misleading survey information can dramatically impact the accuracy of a budget or bid associated with a particular excavation project. An initial survey, for example, may suggest that the subsurface geology for all or most of a predetermined excavation route consists mostly of sand or loose gravel. The contractor's budget and bid will, accordingly, reflect the costs associated with excavating relatively soft subsurface soil. During excavation, however, it may instead be determined that a significant portion of the predetermined excavation route consists of relatively hard soil, such as granite, for example. The additional costs associated with excavating the undetected hard soil are typically borne by the contractor. It is generally appreciated in the excavation industry that such unforeseen costs can compromise the financial viability of a contractor's business.[0004]
• Various methods have been developed to analyze subsurface geology in order to ascertain the type, nature, and structural attributes of the underlying terrain. Ground penetrating radar and infrared thermography are examples of two popular methods for detecting variations in subsurface geology. These and other non-destructive imaging analysis tools, however, suffer from a number of deficiencies that currently limit their usefulness when excavating long, continuous trenches, or when excavating relatively large sites. Further, conventional subsurface analysis tools typically only provide an image of the geology of a particular subsurface, and do not provide information regarding the structural or mechanical attributes of the underlying terrain which is critical when attempting to determine the characteristics of the soil to be excavated.[0005]
• There is a need among developers and contractors who utilize excavation machinery to minimize the difficulty of determining the characteristics of subsurface geology at a predetermined excavation site. There exists a further need to increase the production efficiency of an excavator by accurately characterizing such subsurface geology. The present invention fulfills these and other needs.[0006]
SUMMARY OF THE INVENTION
• The present invention is directed to systems for locating an underground utility. According to one embodiment, a system for locating an underground utility includes means for generating detection data representative of an underground utility within a subsurface of the earth. The system also includes means for generating geographic positioning data representative of a geographic position of the underground utility and means for storing the geographic positioning data and the detection data. The system further includes means for associating the geographic positioning data with the detection data to generate location data representative of a location of the underground utility within the subsurface.[0007]
• According to another embodiment, a system for locating an underground utility includes means for generating location data representative of a location of the underground utility within a subsurface of earth and means for storing utility mapping data comprising at least the location data representative of the location of the underground utility. The system also includes means for facilitating user access to the utility mapping data, such as means for facilitating multiple user access to the utility mapping data. The storing means may further include means for storing as-built utility mapping data and/or means for storing geographic positioning data representative of a geographic position of the underground utility. The system may also include means for displaying one or both of alphanumeric data and images associated with the underground utility.[0008]
• In another embodiment, a system for locating an underground utility includes means for transmitting, while moving a plurality of antennae, electromagnetic probe signals into the subsurface, and means for receiving, while moving the plurality of antennae, electromagnetic return signals from the subsurface. The system also includes means for generating positioning data associated with movement of the plurality of antennae, and means for processing the return signals and positioning data to generate location data representative of a location of an underground object or feature within the subsurface. The processing means may include means for generating a map of the subsurface over which the plurality of antennae is moved.[0009]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a side view of one embodiment of an excavator, termed a track trencher, including a ditcher chain trenching attachment;[0010]
• FIG. 2 is a generalized system block diagram of a track trencher embodiment of an excavator;[0011]
• FIG. 3 is an illustration of a main user interface for controlling a track trencher excavator, for viewing acquired geological and position data, and for interfacing with various electronic and electromechanical components of the excavator;[0012]
• FIG. 4 is a system block diagram of a main control unit (MCU) of a novel excavator data acquisition and control system;[0013]
• FIG. 5 is a system block diagram of a geologic data acquisition unit (GDAU) of a novel excavator data acquisition and control system;[0014]
• FIG. 6 is plot or reflected source electromagnetic signals received by a ground penetrating radar system using a conventional single-axis antenna system;[0015]
• FIG. 7 is a system block diagram of a geographic positioning unit (GPU) of a novel excavator data acquisition and control system;[0016]
• FIG. 8 is a system block diagram of an excavator control unit (ECU) of a novel excavator data acquisition and control system;[0017]
• FIG. 9 is a block diagram of various databases and software accessed and processed by the main control unit (MCU);[0018]
• FIG. 10 is an illustration of a predetermined excavation site having a heterogenous subsurface geology;[0019]
• FIG. 11 is an illustration of a survey profile in chart form obtained for a predetermined excavation route using a novel geologic data acquisition unit (GDAU) and geologic positioning unit (GPU);[0020]
• FIG. 12 is an illustration of an estimated excavation production profile in chart form corresponding to the survey profile chart of FIG. 11;[0021]
• FIG. 13 is an illustration of a predetermined excavation site having a heterogenous subsurface geology and an unknown buried object;[0022]
• FIG. 14 is an illustration of a conventional single-axis antenna system typically used with a ground penetrating radar system for providing two-dimensional subsurface geologic imaging;[0023]
• FIG. 15 is an illustration of a novel antenna system including a plurality of antennas oriented in an orthogonal relationship for use with a ground penetrating radar system to provide three-dimensional subsurface geologic imaging;.[0024]
• FIG. 16 is an illustration of a partial grid of city streets and an excavator equipped with a novel excavator data acquisition and control system employed to accurately map a predetermined excavation site; and[0025]
• FIGS. 17-20 illustrate in flow diagram form generalized method steps for effecting a novel excavator data acquisition and control process.[0026]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• The novel excavator data acquisition and control system and process provides for a substantial enhancement in excavation efficiency and project cost estimation by the acquisition and processing of geological, geophysical, and geographic position information for a particular excavation site. The operation of an excavator is preferably optimized by modifying excavator operating parameters based on acquired survey data and input commands received from an operator of the excavator. The accuracy of estimating the resources and costs associated with excavating a particular excavation site is significantly increased by providing a computational analysis of the acquired survey data prior to initiating excavation of the site, thereby substantially reducing a contractor's risk of misquoting the costs associated with a particular excavation project due to a lack of accurate and detailed information regarding the geology of the subject excavation site.[0027]
• The advantages and features of a novel excavator data acquisition and control system and process will generally be discussed with reference to one particular type of excavator, termed a track trencher. It is to be understood, however, that a track trencher represents only one of many embodiments of an excavator that may be equipped with a novel excavator data acquisition and control system as disclosed hereinbelow. As such, the advantages and features of the disclosed novel system and process are not limited to application in connection with a track trencher.[0028]
• Referring now to the figures, and more particularly to FIG. 1, there is shown an illustration of one embodiment of an excavator well-suited for incorporating a novel data acquisition and control system. A track trencher excavator, shown in Figs.[0029]1 and2, typically includes anengine36 coupled to aright track drive32 and aleft track drive34 which together comprise thetractor portion45 of thetrack trencher30. Anexcavation attachment46, usually coupled to the front of thetractor portion45, typically performs a specific type of excavating operation.
• A[0030]ditcher chain50, or other excavation attachment, is often employed to dig trenches of varying width and depth at an appreciable rate. Theditcher chain50 generally remains above the ground in atransport configuration56 when maneuvering thetrencher30 around an excavation site. During excavation, theditcher chain50 is lowered, penetrates the ground, and excavates a trench at the desired depth and speed while in atrenching configuration58. Another popular trenching attachment, termed a rock wheel in the art, may be controlled in a manner similar to that of theditcher chain50. Atrack trencher30 is well-suited for efficiently excavating a trench along a predetermined excavation route for the purpose of installing various types of pipelines and utility conduits.
• In FIG. 3, there is illustrated a[0031]main user interface101 of atrack trencher30. Propulsion and steering of atrack trencher30 when operating in a transport mode is generally controlled by manipulating the left and right track levers64 and66 which respectively control actuation of the left and right track drives34 and32. Moving theright track lever66 forward, for example, generally causes theright track drive32 to operate in a forward direction and, depending on the relative velocity of theleft track drive34, steers thetrack trencher30 to move in either a left or right direction. Reversing theright track drive32 is generally accomplished by pulling theright track lever66 backwards, thereby causing theright track drive32 to operate in a reverse direction. Propulsion of theleft track drive34 is accomplished in substantially the same manner as that previously described with regard to theright track drive32. Thus, both propulsion and steering are generally controlled by the track levers64 and66 of atrack trencher30. Alternatively, themain user interface101 may be configured to provide for independent steering and propulsion of the left and right track drives34 and32, respectively.
• It is often desirable to maintain the[0032]engine36 at a constant, optimum output level during excavation which, in turn, allows theattachment46 to operate at an optimum excavating output level. A prior art control panel typically includes a plurality of controls and switches, including a speed range switch, RPM knob, steering trim knob, and propel trim knob, all of which must typically be adjusted during normal trenching operation to maintain the engine at the desired engine output level when encounteringvariable attachment46 loading, and to steer thetrack trencher30 in a desired direction. Additionally, a pair of right and left pump potentiometers typically require adjustment and readjustment to equilibrate the operational characteristics of the left and right pumps38 and40.
• A significant disadvantage of a conventional track trencher control panel concerns a requirement that the operator must generally react quickly to changes in[0033]engine36 loading, typically by first determining the appropriate switch to adjust and then the degree of switch adjustment. Typically, minor propulsion modifications are made by adjusting the propel trim knob. Moderate changes to the propulsion level of thetrack trencher30 are generally effected by adjusting the RPM knob. A major modification to the propulsion level of thetrack trencher30 is typically accomplished by switching the speed range switch from a high setting to either a medium or low setting, and once again adjusting the propel trim knob and RPM knob in order to avoid stalling out theengine36.
• The novel data acquisition and control system and process obviates the requirement of continuous manual adjustment and readjustment of a plurality of control switches, knobs, and levers. Instead, an intelligent excavation control unit (ECU) is employed to continuously monitor a network of sensors that transduce various excavator functions into electrical signals, and processes these and other electrical signals to optimize the steering and excavating performance of the excavator, with only minimal intervention by an excavator operator. An enhanced user-interface communicates pertinent excavator performance information, as well as geological and geographical position data, to an operator preferably over a display, such as a liquid crystal display or a cathode ray tube display, for example. A keyboard and other levers and switches are provided on the user-interface to communicate with the data acquisition and control system, and control the operation of the excavator.[0034]
• Data Acquisition and Control System[0035]
• Turning now to FIG. 4, there is illustrated a novel data acquisition and control system shown in system block diagram form. In broad and general terms, the system shown in FIG. 4 significantly enhances the operation of an excavator by the acquisition of geological, geophysical, and position information regarding a particular excavation site, and by employing this information to enhance excavation efficiency. The acquisition of such pertinent excavation site data substantially reduces the risk involved in estimating the cost and scheduling of a particular excavation project. Real-time acquisition of geographical position data provides for precision mapping of an excavated area to accurately identify the location and depth of, for example, buried pipelines and utility conduits installed at the excavation site. These and other significant advantages and features are provided by the novel excavator data acquisition and control system and process as discussed in greater detail hereinbelow.[0036]
• Referring to FIG. 4 in greater detail, the primary processing component of the novel data acquisition and control system is a main control unit (MCU)[0037]250, which preferably includes a central processing unit (CPU)264, Random-Access-Memory (RAM)266, andnon-volatile memory286, such as Electrically Erasable Programmable Read-Only-Memory (EEPROM). TheMCU250 preferably includes appropriate input and output ports to communicate with a number of other sub-systems that acquire various types of data, process such data, and interface with the control system of an excavator to moderate and optimize the excavation process. A main user interface (MUI)101 is preferably situated in proximity to an operator seat mounted to the excavator, and provides a means for communicating with themain control unit250. An excavator control unit (ECU)255 communicates with themain control unit250 and is responsive to operator inputs received from themain user interface101 to cooperatively control the operation of the excavator. A computer orprogrammable controller182 is preferably incorporated as a component of theexcavator control unit255 to control and moderate excavator function.
• The movement and direction of an excavator is preferably monitored and, if desired, moderated by a geographic positioning unit (GPU)[0038]254. Thegeographic positioning unit254 preferably includes a mobile transponder mounted to the excavator and one or more reference transponders. Position reference signals produced by the reference transponders are processed by aCPU270 of thegeographic positioning unit254 into geographic position data, such as latitude, longitude, and elevation data, and displacement data from one or more reference locations, for example.
• An important component of the novel data acquisition and control system concerns a geophysical data acquisition unit (GDAU)[0039]256, which acquires various types of geological and geophysical data for a particular excavation site. In one embodiment, the geophysicaldata acquisition unit256 may be decoupled from themain control unit250 to provide for initial surveying of a predetermined excavation site. After performing the initial survey, the data acquired by the geophysicaldata acquisition unit256 is preferably downloaded into theRAM266 orEEPROM268 of themain control unit250. Alternatively, the geophysicaldata acquisition unit256 is preferably coupled to the excavator and directly to themain control unit250 to provide real-time acquisition of geological, geophysical, and position data during excavation. In yet another embodiment, initial surveying of an excavation site provides for the acquisition of pertinent geological, geophysical, and position data which is downloaded to themain control unit250 upon completion of the initial survey. An onboard geophysicaldata acquisition unit256, which preferably includes the components used in the initial survey, provides for real-time data acquisition which may be used in conjunction with the data acquired from the initial survey to optimize excavator production performance. The geophysicaldata acquisition unit256 preferably includes aCPU276,RAM278, andEEPROM280.
• Among the various types of data acquired by the geophysical[0040]data acquisition unit256, data pertaining to the specific geology at the excavation site, in addition to the physical characteristics of such geology, are of particular importance when optimizing the production performance of an excavator, and when estimating the cost and resource allocation of a particular excavation project. A geologic imaging unit (GIU)258 is preferably coupled to the geophysicaldata acquisition unit256 to provide information concerning the particular geology associated with an excavation site. Various geophysical characteristics associated with a particular geology at the excavation site are preferably determined by a geophysical characterization unit (GCU)260. An auxiliary user interface (AUI)262 is preferably coupled to the geophysicaldata acquisition unit256 to provide local viewing of acquired data and images, and to provide a means for an operator to communicate with the geophysicaldata acquisition unit256. Theauxiliary user interface262 is particularly useful in connection with an embodiment in which the geophysicaldata acquisition unit256 is decoupled from themain control unit250 to perform an initial survey of an excavation site. It is noted that RS-232 communication lines provide sufficient bandwidth for effecting communication between the electronic units and instruments of the novel data acquisition and control system.
• Geophysical Data Acquisition Unit (GDAU)[0041]
• As shown in FIG. 5, the geophysical[0042]data acquisition unit256 preferably includes ageologic imaging unit258 and ageophysical characterization unit260. Thegeophysical characterization unit260 preferably includes a number of geophysical instruments which provide a physical characterization of the geology for a particular excavation site. Aseismic mapping module286 includes an electronic device consisting of multiple geophysical pressure sensors. A network of these sensors are arranged in a specific orientation with respect to the excavator, and are situated so as to make direct contact with the ground. The network of sensors measures ground pressure waves produced below the excavator and in the trench walls produced by the excavator. Analysis of ground pressure waves received by the network of sensors provides a basis for determining the physical characteristics of the subsurface at the excavation site. This data is preferably processed by theCPU276 of the geophysicaldata acquisition unit256 or, alternatively, by theCPU264 of themain control unit250.
• A point load tester[0043]288 may be employed to determine the geophysical characteristics of the subsurface at the excavation site. The point load tester288 preferably employs a plurality conical bits for the loading points which, in turn, are brought into contact with the ground to test the degree to which a particular subsurface can resist a calibrated level of loading. The data acquired by the point load tester288 provides information corresponding to the geophysical mechanics of the soil under test. This data may also be transmitted to the geophysicaldata acquisition unit256 for storage in theRAM278 orEEPROM280.
• The[0044]geophysical characterization unit260 preferably includes aSchmidt hammer290, which is a geophysical instrument that measures the rebound hardness characteristics of a sampled subsurface geology. Other geophysical instruments may also be employed to measure the relative energy absorption characteristics of a rock mass, abrasivity, rock volume, rock quality, and other physical characteristics that together provide information regarding the relative difficulty associated with excavating a given geology. The data acquired by theSchmidt hammer290 is also preferably stored in theRAM278 orEEPROM280 of the geophysicaldata acquisition unit256.
• The[0045]geologic imaging unit258 preferably includes a ground penetrating radar system (GPRadar)282 and anantenna system284. TheGPRadar system282 cooperates with theantenna system284 to transmit source electromagnetic signals into the subsurface of an excavation site. The source electromagnetic signals penetrate the subsurface and are reflected back to theantenna system284. The reflected source electromagnetic signals received by theantenna system284 are amplified and conditioned by theGPRadar system282. In one embodiment, analog reflected source electromagnetic signals processed by theGPRadar system282 are preferably digitized and quantized by aquantizer281. In another embodiment, a digitizingGPRadar system282 performs analog-to-digital conversion of the reflected source electromagnetic signals. The digitized radar data acquired by thegeologic imaging unit258 is preferably stored inRAM278 ornon-volatile EEPROM280 memory in the geophysicaldata acquisition unit256.
• Referring now to FIG. 6, there is illustrated a visual illustration of typical geologic imaging data acquired from a[0046]GPRadar System282 employing a conventional single-axis antenna system284. In FIG. 6, there is plottedGPRadar system282 data acquired over a test site having five different man-made hazards buried at a depth of approximately 1.3 meters in sandy soil with a water table located at a depth of approximately four to five meters. It is noted that the data illustrated in FIG. 6 is representative of data typically obtainable by use of a PulseEKKO 1000 system manufactured by Sensors and Software, Inc. using conventional single-axis 450 MHz center frequency antennas.Other GPRAdar systems282 which may be suitable for this application include SIR System-2 and System-10A manufactured by Geophysical Survey Systems, Inc. and model 1000B STEPPED-FM Ground Penetrating Radar manufactured by GeoRadar, Inc.
• Each of the buried hazards illustrated in FIG. 6 has associated with it a characteristic hyperbolic time-position curve. The apex of the characteristic hyperbolic curve provides an indication of both the position and the depth of a buried hazard. It can be seen from the graph of FIG. 6 that each of the buried hazards is located approximately 1.3 meters below the ground surface, with each of the hazards being separated from adjacent hazards by a horizontal distance of approximately five meters. The[0047]GPRadar System282 data illustrated in FIG. 6 represents geological imaging data acquired using a conventional single-axis antenna system and, as such, only provides a two-dimensional representation of the subsurface being surveyed. As will be discussed in greater detail hereinbelow, anovel antenna system284 comprising multiple antennas arranged in an orthogonal orientation provides for an enhanced three-dimensional view of the subsurface geology associated with a particular excavation site.
• Geographic Positioning Unit (GPU)[0048]
• Turning now to FIG. 7, there is illustrated in greater detail a[0049]geographic positioning unit254 that provides geographic position information regarding the position, movement, and direction of an excavator over an excavation site. In one embodiment, thegeographic positioning unit254 communicates with one or more external reference signal sources to determine information regarding the position of an excavator relative to one or more known reference locations. The relative movement of an excavator over a specified excavation route is preferably determined by theCPU270 of thegeographic positioning unit254, and stored as position data inRAM272 orEEPROM274.
• In another embodiment, geographic position data for a predetermined excavation route is preferably acquired prior to excavating the route. This position data may be uploaded into a[0050]navigation controller292 which cooperates with themain control unit250 and theexcavator control unit255 to provide autopilot-like control and maneuvering of the excavator over the predetermined excavation route. In yet another embodiment, position data acquired by thegeographic positioning unit254 is preferably communicated to aroute mapping database294 which stores the position data for a given excavation site, such as a grid of city streets or a golf course under which various utility, communication, plumbing, and other conduits are buried. The data stored in theroute mapping database294 may be subsequently used to produce a survey map that accurately specifies the location and depth of various utility conduits buried in a specified excavation area.
• In one embodiment, a global positioning system (GPS)[0051]296 is employed to provide position data for thegeographic positioning unit254. In accordance with a U.S. Government project to deploy twenty-four communication satellites in three sets of orbits, termed the Global Positioning System (GPS) or NAVSTAR, various signals transmitted from one or more GPS satellites may be used indirectly for purposes of determining positional displacement of an excavator relative to one or more known reference locations. It is generally understood that the U.S. Government GPS satellite system provides for a reserved or protected band and a civilian band. General, the protected band provides for high-precision positioning to an accuracy of approximately one to ten feet. The protected band, however, is generally reserved exclusively for military and governmental surveillance purposes, and is modulated in such a manner as to render it virtually useless for civilian applications. The civilian band is modulated so as to significantly decrease its usefulness in high-accuracy applications. In most applications, positional accuracies of approximately one hundred to three hundred feet are typical using the civilian band.
• The civilian GPS band, however, can be used indirectly in relatively high-accuracy applications by using one or more civilian GPS signals in combination with one or more ground-based reference signal sources. By employing various known signal processing techniques, generally referred to as differential global positioning system (DGPS) signal processing techniques, positional accuracies on the order of one foot or less are achievable. As shown in FIG. 7, the[0052]global positioning system296 utilizes a signal produced by at least oneGPS satellite302 in cooperation with signals produced by at least twobase transponders304, although use of onebase transponder304 may be satisfactory in some applications. Various known methods for exploiting differential global positioning signals using one ormore base transponders304, together with aGPS satellite signal302 and amobile GPS receiver303 mounted to the excavator, may be employed to accurately resolve excavator movement relative tobase transponder304 reference locations using a GPS satellite signal source.
• In another embodiment, a ground-based positioning system may be employed using a[0053]range radar system298. Therange radar system298 preferably includes a plurality of base radio frequency (RF)transponders306 and amobile transponder308 mounted to the excavator. Thebase transponders306 emit RF signals which are received by themobile transponder308. Themobile transponder308 preferably includes a computer that calculates the range of themobile transponder308 relative to each of thebase transponders306 through various known radar techniques, and then calculates its position relative to allbase transponders306. The position data acquired by therange radar system298 is preferably stored in theRAM272 orEEPROM274 of thegeographic positioning unit254.
• An[0054]ultra-sonic positioning system300, in another embodiment, may be employed together withbase transponders310 and amobile transponder312 mounted to the excavator. Thebase transponder310 emits signals having a known clock timebase which are received by themobile transponder312. Themobile transponder312 preferably includes a computer which calculates the range of themobile transponder312 relative to each of thebase transponders310 by referencing the clock speed of the source ultrasonic waves. The computer of themobile transponder312 also calculates the position of the excavator relative to all of thebase transponders310. It is to be understood that various other known ground-based and satellite-based positioning systems may be employed to accurately determine excavator movement along a predetermined excavation route.
• Excavator Control Unit (ECU)[0055]
• Referring now to FIG. 8, there is illustrated a system block diagram of an excavator control unit (ECU)[0056]255 which communicates with the main control unit (MCU)250 to coordinate the operation of an excavator. In accordance with an embodiment of thetrack trencher excavator30 illustrated in FIGS. 1 and 2, theleft track drive34 typically comprises aleft track pump38 coupled to aleft track motor42, and theright track drive32 typically comprises aright track pump40 coupled to aright track motor44. Left and righttrack motor sensors198 and192 are preferably coupled to the left andright track motors42 and44, respectively. The left and right track pumps38 and40, deriving power from theengine36, preferably regulate oil flow to the left andright track motors42 and44 which, in turn, provide propulsion for the left and right track drives34 and32. Theexcavation attachment46 preferably comprises anattachment motor48 and anattachment control98, with theattachment46 preferably deriving power from theengine36. Asensor186 is preferably coupled to theattachment motor46. Actuation of theleft track motor42,right track motor44, andattachment motor48 is monitored bysensors198,192, and186 respectively. The output signals produced by thesensors198,192, and186 are communicated to thecomputer182.
• In response to steering and propel control signals respectively produced by the[0057]steering control92 and propelcontrol90, thecomputer182 communicates control signals, typically in the form of control current, to the left and right track pumps38 and40 which, in turn, regulate the speed at which the left andright track motors42 and44 operate. The left and righttrack motor sensors198 and192 communicate track motor sense signals to thecomputer182 indicative of the actual speed of the left andright track motors42 and44. Similarly, anengine sensor208, coupled to theengine36, provides an engine sense signal to thecomputer182, thus completing a closed loop control system for thetractor drive portion45 of atrack trencher30. Those skilled in the art will recognize that various known computer configurations will provide a suitable platform for effectuating propulsion and steering changes of atrack trencher30 in response to the propel and steering signals produced by the propel and steering controls90 and92.
• The[0058]excavation attachment46 portion of atrack trencher30 includes anattachment motor48,attachment control98, and at least oneattachment sensor186. Theattachment motor48 preferably responds to instructions communicated to theattachment control98 from thecomputer182. The actual output of theattachment motor48 is monitored by theattachment sensor186, which produces an attachment sense signal received by thecomputer182.
• In one embodiment, the left and right[0059]track motor sensors198 and192 are of a type generally referred to in the art as magnetic pulse pickups, or PPUs. ThePPUs198 and192 transduce track motor rotation into a continuous series of pulse signals, wherein the pulse train preferably represents the frequency of track motor rotation as measured in revolutions-per-minute. When a transport mode of travel is selected, the propelcontrol90 preferably produces a transport propel control signal which is representative of a target velocity for the left andright track motors42 and44. typically measured in revolutions-per-minute. Conversion of the transport propel signal into a target track motor velocity may be accomplished by the propelcontrol90 itself or. preferably, by thecomputer182. Thecomputer182 typically compares the left and right track motor sense signals respectively produced by the left andright PPU sensors198 and192 to the target track motor propulsion level represented by the transport propel signal. Thecomputer182 communicates the appropriate pump control signals to the left and right track pumps38 and40 in response to the outcome of the comparison to compensate for any deviation between the actual and target track motor propulsion levels.
• A[0060]display73 is coupled to thecomputer182 or, alternatively, to themain control unit250, and preferably communicates messages indicative of operating status, diagnostic, calibration, fault, safety, and other related information to an operator. Thedisplay73 provides quick, accurate, and easy-to-understand information to an operator by virtue of the interpretive power of thecomputer182 which acquires and processes data from a plurality of track trencher sensors, and various geological and geophysical instruments. Geologic imaging data and related geophysical information, for example, is visually displayed on thedisplay73. Further, information regarding the position of the excavator as it traverses along a predetermined excavation route, as well as signal quality information received from thegeographic positioning unit254, is displayed on thedisplay73. Akeyboard75 is also provided on themain user interface101 to permit an operator to communicate with theexcavator control unit255 and themain control unit250.
• Main Control Unit (MCU)[0061]
• Turning now to FIG. 9, there is illustrated a block diagram of various databases and software that are utilized by the main control unit (MCU)[0062]250 when accessing and processing geological, geophysical, position, and operational data associated with surveying and excavating a selected excavation site. The data acquired by the geophysicdata acquisition unit256, for example, is preferably stored in adatabase326, which includes aGPRadar database328, ageologic filter database330, and ageophysics database332. TheGPRadar system282 data, as previously discussed, is preferably digitized and stored in theGPRadar database328 in a suitable digital format appropriate for correlation to data stored in other system databases. Ageologic filter database330, as will be discussed in greater detail hereinbelow includes filtering data produced by correlating GPRadar data to corresponding excavator production data stored in theexcavation performance database324. Correlation andoptimization software320 performs the correlation of GPRadar data to actual excavator production data to develop an array of adjustable geologic digital filters that can be effectively overlaid with real-time acquired geologic image data to exclude or “filter out” verified geology data, thus leaving unverified images representative of one or more buried hazards. By way of further illustration, a particular type of soil produces a characteristic return radar image which can be correlated with excavator production data acquired by theexcavator control unit255. Excavating through granite, for example, produces a characteristic return radar image that can be correlated to various excavator operation parameters, such asexcavation attachment motor48 speed,engine36 loading, and left orright track motor42 and44 velocity changes.
• An “excavation difficulty” parameter or set of parameters are preferably computed based on the excavator operating parameters. The “excavation difficulty” parameters are then associated with the characteristic reflected radar image data corresponding to a particular geology, such as granite, for example. An array of “excavation difficulty” filter parameters and associated reflected radar image data values are preferably developed for a wide range of soil and rock, and stored in the[0063]geologic filter database330.
• An excavation.[0064]statistics database316 preferably receives data files from the correlation andoptimization software320 and compiles statistical data to reflect actual excavator production performance relative to specific geology, maintenance, and equipment variables. In one embodiment, GPRadar data and geophysical data is acquired by the geophysicdata acquisition unit256 during an initial survey of a predetermined excavation route. This data is preferably uploaded to theexcavation statistics database316 prior to excavating the predetermined route. The data stored in theexcavation statistics database316 can be viewed as a production estimate in the sample geology based on past excavator production performance.
• The[0065]main control unit250 also executesECU control software318 which receives data files from the correlation andoptimization software320 and input commands received from themain user interface101. TheECU control software318 compiles a current operation standard for operating the excavator over the course of the predetermined excavation route. If input data received from themain user interface101 causes a modification in the operation standard, theECU control software318 computes modified excavator operational instructions which are transmitted to themain control unit250 and theexcavator control unit255 which, in turn, modifies the operation of the excavator in response to the modified operation standard.
• A[0066]maintenance log memory314 preferably includes non-volatile memory for storing various types of excavator maintenance information. An elapsed time indicator is preferably included in themaintenance log memory314 which indicates the total elapsed operating time of the excavator. At predefined operating time values, which are preferably stored in themaintenance log memory314, the excavator operator is prompted by themain user interface101 that scheduled service is required. Verification of scheduled service, the type of service, the date of service, and other related information is preferably input through themain user interface101 for permanent storage in themaintenance log memory314. In one embodiment, themaintenance log memory314 preferably includes a table of factory designated operational values and ranges of operational values associated with nominal excavator operation. Associated with each of the operational values and ranges of values is a status counter which is incremented upon each occurrence of excavator operation outside of the prescribed values or range of values. The status counter information is useful in assessing the degree to which an excavator has been operated outside factory specified operational ranges, which is particularly useful when determining the appropriateness of warranty repair work.
• Geological Surveying and Imaging[0067]
• In general operation, as shown in FIG. 10, a predetermined excavation route is preferably initially surveyed using the[0068]geographic positioning unit254 and the geophysicdata acquisition unit256. In one embodiment, thegeographic positioning unit254 and geophysicdata acquisition unit256 are positioned in atransport cart340 which is pulled along the predetermined excavation route by avehicle342. In the illustrative example shown in FIG. 10, the excavation route is a county road under which a utility conduit is to be installed. As thetransport cart340 is pulled along theroadway344, data received from thegeologic imaging unit258 is acquired for the purpose of determining the soil properties of the subsurface below theroadway344. Concurrently, geographic position data is acquired by thegeographic positioning unit254 as thevehicle342 andtransport cart340 traverse theroadway344. As such specific geologic data obtained from thegeologic imaging unit258 may be correlated to specific geographic locations along theroadway344.
• The[0069]geologic imaging unit258 preferably includes aGPRadar system282 which is typically calibrated to penetrate to a pre-established depth associated with a desired depth of excavation. Depending on the pre-determined excavation depth, various types of soil and rock may be encountered along -the predetermined excavation route. As shown in FIG. 10, a layer ofroad fill346, which lies immediately below theroadway344, has associated with it a characteristic geologic profile GP₁and a corresponding geologic filter profile GF₁which, as previously discussed, represents a correlation between excavation production performance data to reflected radar image data for a particular soil type. As thetransport cart340 traverses theroadway344, various types of soil and subsurface structures are detected, such as asand layer354,gravel352,bedrock350, andnative soil348, each of which has a corresponding characteristic geologic profile and geologic filter profile.
• Upon completion of the initial survey, the data acquired and stored in the geophysic[0070]data acquisition unit256 andgeographic positioning unit254 is preferably downloaded to a separate personal computer (PC)252. ThePC252 preferably includes excavation statistics software and an associateddatabase316 to correlate the acquired survey data with historical excavator production performance data to produce an estimation as to expected excavator performance over the surveyed route. The performance estimates may further be used as a basis for computing the time and cost involved in excavating a particular area based on actual geological data and historical production performance data.
• After completion of the initial survey, the geophysic[0071]data acquisition unit256 is preferably coupled to themain control unit250 on the excavator prior to initiating excavation along the surveyed route. During excavation, as previously discussed, the various databases containing geological, geophysical, position, and excavator operating performance data are processed by themain control unit250. Themain control unit250, in cooperation with theexcavator control unit255, adjusts the operation of the excavator as it traverses and excavates along the surveyed route to optimize excavation.
• Referring now to FIG. 11, there is illustrated an example of a survey profile obtained by transporting the geophysic[0072]data acquisition unit256 andgeographic positioning unit254 along a predetermined excavation route. It is noted that in this illustrative example, the length of the excavation route is defined as the distance between Location L₀and Location L₅. A corresponding estimated excavation production profile for the predetermined excavation route is shown in FIG. 12.
• Referring to FIG. 11 in greater detail, distinct changes in subsurface geological characteristics can be observed at locations L[0073]₁, L₂, L₃, and L₄, which are associated with corresponding changes in the “excavation difficulty” parameter plotted along the Y-axis of the survey profile chart. Between locations L₀and L₁, for example, thegeologic profile GP₁362 of the subsurface has associated with it a corresponding excavation difficulty parameter of D₁. The geologic imaging data at L₁indicates a transition in the subsurface geology to soil having a geologic profile of GP₂364 and a corresponding excavation difficulty parameter of D₂, thus indicating a transition to relatively softer soil.
• The estimated excavation production profile data shown in FIG. 12 indicates a corresponding transition from an initial[0074]production profile PP₁372 to anotherproduction profile PP₂374 at location L₁. It is noted that the rate of excavation is plotted along the Y-axis of the excavation production profile chart. Based on the survey profile data for the subsurface geological characteristics between locations L₀and L₂, it can be seen that an initial excavation rate R₁is estimated for the portion of the predetermined excavation route between locations L₀and L₁, and an increased excavation rate of R₂between excavation route locations L₁and L₂due to the lower excavation difficulty parameter D₂associated with geologic profile GP₂364. It can be seen that a similar relationship exists between a particular excavation difficulty parameter and its corresponding estimated excavation rate parameter.
• In general, excavation difficulty parameters of increasing magnitude are associated with corresponding excavation rate parameters of decreasing magnitude. This generalized inverse relationship reflects the practical result that excavating relatively hard soil, such as granite, results in a relatively low excavation rate, while excavating relatively soft soil, such as sand, results in relatively high excavation rates. It is noted that associated with each particular geologic profile (GP[0075]_X) and production profile (PP_X), there exists a corresponding excavation time, such as excavation time T₁associated withgeologic profile GP₁362 andproduction profile PP₁372. As such, a total estimated excavation time for a particular predetermined excavation route can be obtained by summing each of the individual excavation time parameters T₁through T_N.
• The survey profile data of FIG. 11 associated with[0076]geologic profile GP₄368 between excavation route locations L₃and L₄indicates a discontinuity at this location. The excavation production profile data of FIG. 12 corresponding to this portion of the predetermined excavation route indicates a corresponding discontinuity in the excavation rate estimation which is shown diverging toward zero. The data for this portion of the predetermined excavation route indicates the existence of extremely tough soil or, more likely, a man-made hazard, such as a concrete or steel pipeline, for example. Further investigation and surveying of the specific area may be warranted, which may require removal of the hazard or modification to the predetermined excavation route.
• A more realistic geologic profile for a particular length of the predetermined excavation route is illustrated as[0077]geologic profile GP₅370 shown between excavation route locations L₄and L₅. The excavation difficulty parameter for this geologic profile results in an averaged parameter of D₅. Accordingly, an averaged excavation rate of R₅may be appropriate when excavating this portion of the predetermined route. Alternatively, the excavation rate associated with theproduction profile PP₅380 may be moderated by theexcavator control unit255 to optimize the excavation rate based on such fluctuations in excavation difficulty. It is understood that the ability of an excavator to respond to such fluctuations in excavation rate is generally limited by various mechanical and operational limitations.
• Turning now to FIG. 13, there is illustrated a heterogeneous composition of differing soil types over a predetermined excavation route having a predefined distance of L[0078]_S. The soil inregion1, for example, has a geologic profile of GP₁and a corresponding geologic filter profile of GF₁. Each of the other soil types illustrated in FIG. 13 has a corresponding geologic profile and geologic filter profile value. It is assumed that thegeologic filter database330 contains geologic filter data for each of theregions1,2,3 and4 illustrated in FIG. 13. A significant advantage of the novel hazard detection process performed by the geophysicdata acquisition unit256 concerns the ability to quickly detect the existence of an unknown buriedstructure401. The correlation andoptimization software320 executed by themain control unit250 preferably filters out known geology using a corresponding known geologic filter profile to exclude the known or verified geology data from data associated with a survey scan image. Filtering out or excluding the known or verified geology data results in imaging only unverified buriedstructures401. By excluding known geological data from geologic imaging survey scan data, unknown or suspect buried structures are clearly recognizable.
• Referring now to FIG. 14, there is illustrated a conventional antenna configuration for use with a ground penetrating radar system. Generally, a single-axis antenna, such as the one illustrated as antenna-[0079]A382 oriented along the Z-axis, is employed to perform multiple survey passes384 when attempting to locate a potential buriedhazard386. Generally, a ground penetrating radar system has a time measurement capability which allows measuring of the time for a signal to travel from the transmitter, bounce off a target, and return to the receiver. This time function can be calibrated to the velocity of a specific subsurface condition in order to measure distance to a subsurface object or horizon. Calculations can be used to convert this time value to a distance measurement that represents the depth of the target based upon field determined values for characteristic soil properties, such a dielectric and wave velocity through a particular soil type. A simplified technique that can be used when calibrating the depth measurement capabilities of a particular ground penetrating radar system involves coring a sample target, measuring its depth, and relating it to the number of nanoseconds it takes a wave to propagate.
• After the time function capability of the ground penetrating radar system provides an operator with depth information, the radar system is moved laterally in a horizontal (X) direction, thus allowing for the construction of a two-dimensional profile of a subsurface. By performing multiple survey passes in a series of[0080]parallel lines384 over a particular site, a buriedhazard386 may be located. It can be appreciated, however, that the two-dimensional imaging capability of aconventional antenna configuration382 can result in missing a buried hazard,386, particularly when thehazard386 is parallel to the direction of asurvey pass384.
• A significant advantage of a novel geologic[0081]imaging antenna configuration284 provides for three-dimensional imaging of a subsurface as shown in FIG. 15. A pair of antennas, antenna-A388 and antenna-B390, are preferably employed in an orthogonal configuration to provide for three-dimensional imaging of a buriedhazard386. It is noted that the characteristic hyperbolic time-position data distribution, as shown in two-dimensional form in FIG. 6 by use of a conventional single-axis antenna, may instead be plotted as a three-dimensional hyperbolic shape that provides width, length, and breadth dimensions of a detected buriedhazard386. It is further noted that a buriedhazard386, such as a drainage pipeline, which runs parallel to thesurvey path392 will immediately be detected by the three-dimensionalimaging GPRadar system282. Respective pairs of orthogonally oriented transmitting and receiving antennas are preferably employed in theantenna system284 of thegeological imaging unit258.
• Excavation Site Mapping[0082]
• Turning now to FIG. 16, there is illustrated an[0083]excavator410 performing an excavation operation along acity street420 of acity street grid422. An important advantage of the novelgeographic positioning unit254 of theexcavator410 concerns the ability to accurately navigate along a predetermined excavation route, such as acity street420, and to accurately map the excavation route in aroute mapping database294 coupled to thegeographic positioning unit254. It may be desirable to initially survey acity street grid422 for purposes of accurately establishing an excavation route for each of theapplicable city streets420 comprising thecity street grid422, for example. This data is preferably loaded into thenavigation controller292 of thegeographic positioning unit254.
• As the[0084]excavator410 progresses along the excavation route defined for each of thecity streets420, actual position data is acquired by thegeographic positioning unit254 and stored in theroute mapping database294. Any deviation from the predetermined excavation route stored in thenavigation controller292 is accurately recorded in theroute mapping database294. Upon completion of an excavation effort, the data stored in theroute mapping database294 may be downloaded to aPC252 to construct an “as built” excavation map of thecity street grid422.
• Accordingly, an accurate survey map of utility or other conduits installed along the excavation route may be constructed from the route mapping data and subsequently referenced by workers desiring to gain access to, or avoid, the buried conduits. It is to be understood that excavating one or more city streets for the purpose of installing utility conduits as shown in FIG. 16 is provided for illustrative purposes, and does not represent a limitation on the application of the geographic positioning and route mapping capability of the novel excavator data acquisition and control system.[0085]
• Still referring to FIG. 16, accurate navigation and mapping of a prescribed excavation route may be accomplished by a[0086]global positioning system296,range radar system298 orultrasonic positioning system300, as discussed previously with respect to FIG. 7. An excavator data acquisition and control system utilizing aGPS296 configuration preferably includes first andsecond base transponders404 and408 together with one or more GPS signals received from a corresponding number ofGPS satellites302. Amobile transponder402, preferably mounted to theexcavator410, is provided for receiving theGPS satellite signal412 and base transponder signals414 and418 respectively transmitted from thebase transponders404 and408. As previously discussed, a modified form of differential GPS positioning techniques may be employed to enhance positioning accuracy to one foot or less.
• In another embodiment, a ground-base[0087]range radar system298 includes threebase transponders404,408, and406 and amobile transponder402 mounted to theexcavator410. It is noted that a third ground-basedtransponder406 may be provided as a backup transponder for a system employing aGPS satellite signal412 in cases where aGPS satellite signal412 transmission is temporarily terminated. Position data is preferably processed and stored by thegeographic positioning unit254 using the threereference signals414,416, and418 received from the three ground-basedradar transponders404,406, and408. An embodiment employing anultrasonic positioning system300 would similarly employ three base transponders,404,406, and408 together with amobile transponder402 mounted to theexcavator410.
• Excavator data Acquisition and Control Process[0088]
• Turning now to FIGS. 17-20., there is illustrated in flowchart form generalized process steps associated with the novel excavator data acquisition and control system and process. Initially, as shown in FIG. 17, a number of ground-based transponders are positioned at appropriate locations along a predetermined excavation route at[0089]step500. The geophysicdata acquisition unit256 andgeographic positioning unit254 are then situated at an initial location L₀of the excavation route atstep502. Thegeologic imaging unit258,geophysical characterization unit260, andgeographic positioning unit254 are then initialized or calibrated atstep504. After initialization, the geophysicdata acquisition unit256 andgeographic positioning unit254 are transported along the excavation route, during which GPRadar, position, and geophysical data is acquired atsteps506,508, and510. The data acquired by theGPRadar system282 is preferably digitized and quantized atstep512. Data acquisition continues atstep516 until the end of the excavation route is reached, as atstep518. The acquired data is then preferably downloaded to aPC252 or directly to themain control unit250.
• At[0090]step530, shown in FIG. 18, excavation statistical software is preferably executed on the data acquired during the excavation route survey. Atstep532, historical excavator production data is transferred from theexcavation statistics database316 to thePC252. The data acquired during the survey is also loaded into the PC atstep534. The excavation statistical software then performs a correlation between the acquired GPRadar data and the historical excavatorproduction data step536.
• In one embodiment, correlation between GPRadar data and historical production data is accomplished by use of various known matrix manipulation techniques. A historical production data matrix is preferably produced at[0091]step538 by correlating geologic image data (ID_X) with corresponding excavator production data (PD_X). A correlation value (CV_XX) is produced corresponding to each pair of geologic image data and production data parameters. The correlation value CV₂₂, for example, is a correlation value associated with a statistical correlation between geologic image data parameter ID₂and excavator production data parameter PD₂. Associated with each geologic image data parameter is an associated time parameter and location parameter, such as T₁and L₁associated with geologic image data parameter ID₁. It can be seen that correlation values associated with a plurality of geologic image data and production data parameter pairs can be produced for time and position increments along a predetermined excavation route.
• At[0092]step540, actual geologic image data is acquired over the excavation route and preferably processed as a matrix of discrete geologic image data for corresponding discrete time and location distance increments. Atstep542, the matrices produced atsteps538 and540 are manipulated to produce a correlation matrix in which an estimated or projected production data parameter (PD_XX) is associated with a pair of corresponding actual geologic image data (ID_X) and correlation value (CV_X) parameter pairs. For example, an estimated production data parameter PD₃is associated with actual geologic image data parameter ID₃and correlation value parameter CV₃. It is noted that each of the estimated production data parameters is associated with a corresponding time and distance location increment.
• The estimated production performance parameters for a particular excavation route are computed at[0093]step550 as shown in FIG. 19. The total estimated time (ET_T) to excavate the entire excavation route can be estimated by summing the discrete time increments T₁through T_N. The operational costs associated with excavating the predetermined excavation route can be determined by summing the operational costs associated with each of the discrete portions along the route. The estimated labor costs (LC_T) can be estimated by multiplying the total estimated excavation time (ET_T) by the total man hour cost per hour. An estimation of the grand total of costs (GT_E) can be determined by summing all of the production costs and labor costs associated with excavating the entire route.
• At[0094]step552, the estimated excavator operation parameters are computed. For the portion of the excavation route defined between reference location L₀and L₁, for example, the estimated production data may indicate an optimal left track velocity (V_L) of 125 feet per minute (FPM) and a right track velocity (V_R) of 125 FPM. Further, the estimated production data may suggest an optimal-excavation attachment speed of approximately 110 RPM and a target engine speed of 2,250 RPM. It is noted that the left and right track velocities V_{L and VR}of 125 FPM, respectively, represents straight tracking by the excavator along the excavation route.
• It can be seen that along the excavation route defined between location L[0095]₁and L₂, it is indicated that the excavator is steering in a right direction since the left track velocity V_Lof 230 FPM is greater than the right track velocity V_Rof 150 FPM. Also, it is indicated that the excavating attachment speed is increasing to 130 RPM, and that the target engine speed is increasing to 2,400 RPM, thus indicating the presence of relatively softer soil within the region defined between locations L₁and L₂. Along the excavation route defined between locations L₂and L₃, it is indicated that the excavator is again tracking in a straight direction and at a relatively slow velocity of 60 FPM, thus indicating the presence of relatively hard subsurface soil. A corresponding slower excavating attachment speed of 100 RPM and lower target engine speed of 2,100 RPM are indicated due to the slower excavator velocity.
• At[0096]step560, as shown in FIG. 20, the estimated excavation operating parameters produced atstep552 are loaded into themain control unit250. Excavation is initiated beginning at reference location L₀atstep562. Atstep564, themain control unit250 monitors the excavator operational parameters, and out-of-range conditions are recorded in themaintenance log memory314. Actual production performance parameters are acquired by theexcavator control unit255, atstep568, and transferred to themain control unit250. Any inputs received from themain user interface101 are also transferred to the main control unit atstep570. If the actual production performance parameters received from theexcavator control unit255 differ by a predetermined amount from the estimated excavation operation parameters, as tested atstep572, themain control unit250 optimizes the estimated parameters atstep574, and transmits the optimized parameters to theexcavator control unit255 to effect the necessary changes to excavator operation atstep576. Excavation continues atstep578 until the end location of the predetermined excavation route is reached atstep580, after which the excavation operation is terminated, as atstep582.
• It will, of course, be understood that various modifications and additions can be made to the preferred embodiments discussed hereinabove without departing from the scope or spirit of the present invention. Accordingly, the scope of the present invention should not be limited by the particular embodiments discussed above, but should be defined only by the claims set forth below and equivalents of the disclosed embodiments.[0097]

Claims (20)

What is claimed is:

1. A system for locating an underground utility, comprising:

means for generating detection data representative of an underground utility within a subsurface of the earth;

means for generating geographic positioning data representative of a geographic position of the underground utility;

means for storing the geographic positioning data and the detection data; and

means for associating the geographic positioning data with the detection data to generate location data representative of a location of the underground utility within the subsurface.

2. The system ofclaim 1, wherein the detection data generating means comprises means for transmitting an electromagnetic source. signal directed at the subsurface and means for receiving an electromagnetic return signal.

3. The system ofclaim 1, wherein the detection data generating means comprises means for transmitting a seismic source signal directed at the subsurface and means for receiving a seismic return signal.

4. The system ofclaim 1, wherein the positioning data generating means comprises means for receiving a plurality of ground-based position signals.

5. The system ofclaim 1, wherein positioning data generating means comprises means for receiving a plurality of ground-based position signals and means for receiving at least one position signal from space.

6. The system ofclaim 1, further comprising means for generating data representative of a two-dimensional location of the underground utility within the subsurface using the associated positioning and detection data.

7. The system ofclaim 1, further comprising means for generating data representative of a three-dimensional location of the underground utility within the subsurface using the associated positioning and detection data.

8. A system for locating an underground utility, comprising:

means for generating location data representative of a location of the underground utility within a subsurface of earth;

means for storing utility mapping data comprising at least the location data representative of the location of the underground utility; and

means for facilitating user access to the utility mapping data.

9. The system ofclaim 8, wherein the facilitating means comprises means for facilitating multiple user access to the utility mapping data.

10. The system ofclaim 8, wherein the storing means comprises means for storing data representative of a two-dimensional location of the underground utility within the subsurface.

11. The system ofclaim 8, wherein the storing means comprises means for storing data representative of a three-dimensional location of the underground utility within the subsurface.

12. The system ofclaim 8, wherein the storing means further comprises means for storing as-built utility mapping data.

13. The system ofclaim 8, wherein the storing means further comprises means for storing geographic positioning data representative of a geographic position of the underground utility.

14. The system ofclaim 8, wherein the storing means further comprises means for storing detection data representative of one or both of the underground utility and the subsurface of the earth within which the underground utility is located.

15. The system ofclaim 8, further comprising means for displaying one or both of alphanumeric data and images associated with the underground utility.

16. A system, comprising:

means for transmitting, while moving a plurality of antennae, electromagnetic probe signals into the subsurface;

means for receiving, while moving the plurality of antennae, electromagnetic return signals from the subsurface;

means for generating positioning data associated with movement of the plurality of antennae; and

means for processing the return signals and positioning data to generate location data representative of a location of an underground object or feature within the subsurface.

17. The system ofclaim 16, wherein the processing means comprises means for generating a map of the subsurface over which the plurality of antennae is moved.

18. The system ofclaim 16, further comprising means for acquiring one or more geophysical parameters associated with the subsurface.

19. The system ofclaim 16, wherein the plurality of antennae comprise a plurality of transmit antennae and a plurality of receive antenna, further wherein at least two of the transmit antennae are oriented substantially orthogonal to one another and at least two of the receive antennae are oriented substantially orthogonal to one another.

20. The system ofclaim 16, further comprising means for displaying data developed from the return signals.

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