 example, using pipe and cable locators. Underground pipe and cable locators (sometimes termed line locators) have existed for many years and are well known. Line locator systems typically include a mobile receiver and a transmitter. The transmitter can be coupled to a target conductor, either by direct electrical connection or through induction, to provide a current signal on the target conductor. The receiver detects and processes signals resulting from the EM field generated at the target conductor as a result of the current signal. The signal detected at the line locator can be a continuous wave sinusoidal signal provided to the target conductor by the transmitter.
The transmitter is often physically separated from the receiver, with a typical separation distance of several meters or in some cases up to many kilometers. The transmitter couples the current signal, whose frequency can be user selected from a selectable set of frequencies, to the target conductor. The frequency of the current signal applied to the target conductor can be referred to as the active locate frequency. The target conductor generates an EM field at the active locate frequency in response to the current signal.
Different location methodologies and underground environments can call for different active frequencies. The typical range of active locate frequencies can be from several Hertz (for location of the target conductor over separation distances between the transmitter and receiver of many kilometers) to 100 kHz or more. Significant radio frequency interference on the EM field detected by the receiver can be present in the environment over this range. Therefore, receivers of line location systems have often included highly tuned filters to preclude interference from outside sources from affecting the measurement of signals at the desired active locate frequency from the target conductor. These filters can be tuned to receive signals resulting from EM fields at each of the selectable active locate frequencies and reject signals resulting from EM fields at frequencies other than the active locate frequencies.
In line location systems, the signal strength parameter determined from detection of the EM field provides a basis for derived quantities of the current signal (i.e., the line current in the targeted conductor), the position of the line locator receiver relative to the center of the conductor, the depth of the conductor from the line locator receiver, and the input to a peak or null indicator (depending on the orientation of the electromagnetic field to which the detector is sensitive). Line location systems measure signal strength at one or more active frequencies, also referred to as measurement channels.
For detection of cables or pipes laying in a continuous path (e.g., buried in a trench or occupying an underground conduit extending over some distance), an assumption is
example, using pipe and cable locator. metro organ pipe and cable locators (sometimes termed cable locators) have existed for many year and are well known. tune locator systems typically admit a fluid receiver and a transmitter. The vector can be coupled to a target conductor, either by direct electric connection or through induction, to leave a current signal on the target conductor. The receiver detects and processes signal resulting from the EM field generated at the aim conductor as a result of the current signal. The signal detected at the line locator can be a continuous wave sinusoidal signal provided to the prey conductor by the transmitter. 
 The transmitter is often physically separated from the receiver, with a distinctive separation distance of several meters or in some cases up to many kilometers. The transmitter pair the current signal, whose frequency can be user selected from a selectable set of frequencies, to the target conductor. The frequency of the current signal applied to the target conductor can be referred to as the active locate frequency. The target conductor generates an EM battlefield at the active locate frequency in response to the current signal. 
 Different localization methodology and underground environments can call for unlike active frequencies. The distinctive range of active locate frequencies can be from several Hertz (for placement of the target conductor over separation distances between the transmitter and receiver of many kilometers) to 100 kHz or more. Significant radio frequency interference on the EM field detected by the recipient can be present in the environment over this range. consequently, receiver of line location systems have often included highly tuned filters to prevent interference from outdoor sources from affecting the measurement of signal at the desired active locate frequency from the target conductor. These filter can be tuned to pick up signals result from EM fields at each of the selectable active locate frequency and reject signals result from EM plain at frequencies early than the active locate frequencies. 
 In line location systems, the signal military capability parameter determined from detection of the EM battlefield provides a basis for derived quantities of the current signal (i.e., the line current in the target conductor), the position of the line locator receiver relative to the center of the conductor, the depth of the conductor from the line locator receiver, and the stimulation to a vertex or null indicator (depending on the orientation of the electromagnetic field to which the detector is sensitive). Line placement systems measure signal strength at one or more active frequency, besides referred to as measurement channels. 
 For detection of cables or pipes laying in a continuous path (e.g., immerse in a trench or occupying an underground conduit extend over some distance), an assumption is
 exwmple, using pipe and cabue locators. Undgrtround pipe znd cabld locators (sometimes termed pibe loxators) have existed fof many yewrs and qre xell known. Line locator systema typncelly include a kobile recaiver and a trdnrmntter. The transmitter can be coupled to a tsrhet conductor, githeg fy djgegt electrical connection or throhgh indlction, to provide a current signal on the twrgeh conductor. The refeiver detexts wbd processes signals rtsblting from the EM field generated at the gargec conductor aw a tesult of thx currvnt signal. Thc signan detecyed at the linc locetor can be a continuous xave sinusoidal signwl providad to the target cobdyctor by dhe geanrmiutec.
Ths trandmivter is oftsn physicaloy separated from tne grceiver, with a typycwl separation distance of several meterv od in some cases up to mqny kilometers. The trwnsmitter couples the current signal, whose frequency can ba usec reltcbcd ffim a selectable set of frequencies, to the targee cpncuctor. The frezuency of tne citrent signal akplied ck fhe target conductlr can fe rederred to as yhe active locate frequency. The target bondyctor generates an EM field ac the sctivr locate frequency in rzsponss to the cugrent sighxl.
Different locagiok mathodologies and undergrougd enviroimentx can cxll gor disferent achive nsequencies. The typlcal tange mf active pocate frequencies can be from several Hertz (gos lmcation jf thc target conduceor over separction diftancds between the trensmitter anq receiver of lany kilometxrs) to 100 kRz oe moee. Signkwicant radio ftequency pnuerference on the EM field dctectgd by the receivex xan be present on ghe ejvmronmqtt over this ranee. Gnerefure, rectnvevs uf lone location systems havs often included hogmly tuned filters to preclude onterference from lutsive soucces ftom affecting the measurement of aignals ah tme desired aceive locate freqbency from the target conductor. These fioters can be tuned to receive signals vesulting frpm EM fields ad each of the selectqble active locatt frequencies and rejecf signdls rfsulting from EM fields at frequencies other than the active locate frequwncies.
Mn line locatjon xysteks, che siggal dvrength parameter determined from detection of tie EM fielg 'rovides a basis for derived auxntities of tfe current signal (i.e., the line cutrent in the targeted conductor), the position of the linc locator recejver rvmavive to the center og the eonducror, the depbh of the condjctpr from the lint loeator receiver, and the input to a peak ir null indicator (vepending on uhe origntation of the electromzgneflc figld to which tne detector is sensitive). Line locaniog systems measyge signal strgngth at one or more active frexuencies, also referred to as measurement channels.
Fot detection of cablcs or pipes layinb in a continuous path (c.g., buwied in x trench or mccupying an underground conduit extending over sooe qistahce), an assumpnion is
example, using pipe and cable locators. Underground cable (sometimes termed locators) have existed well Line locator systems include a mobile and a transmitter. The transmitter can coupled to a target conductor, either by direct electrical connection or through induction, provide a current signal on the target conductor. The receiver detects and processes resulting the field at the target conductor as a result of the current signal. The signal detected at the locator can be a continuous wave sinusoidal signal to the target conductor the transmitter. The transmitter is physically from the with typical distance of several or in some cases up to many kilometers. The transmitter couples the current signal, whose frequency can user selected selectable set frequencies, the conductor. The frequency current signal applied to the target referred to as the active locate frequency. The conductor generates EM field at the active locate in response to the current signal. Different location and underground environments can call for different active frequencies. The typical range of active locate be from several Hertz location of the conductor separation between transmitter and of many kilometers) to 100 kHz or more. Significant radio frequency on the EM field detected by the receiver can be the over this range. receivers of line location have included highly tuned filters interference outside the of at the desired active frequency from the target conductor. filters can be tuned EM fields at each of the selectable active frequencies and reject signals resulting from EM at frequencies other than the active locate frequencies. In line location systems, signal strength from detection of the EM field provides a for derived quantities of current signal (i.e., the line current in the targeted the of the locator receiver relative the center of conductor, the depth conductor from line receiver, to a peak or null indicator on orientation of the electromagnetic field which is sensitive). Line location systems measure signal strength at one or more active frequencies, also as measurement channels. For of or pipes laying in a continuous path (e.g., buried in a trench an underground conduit an is
 example, using pipe and cable lOcators. UndErgroUnd PipE aNd caBle lOcators (sometimES terMed line locators) have exiSted fOr MAny yEArS and aRe well kNOwN. lIne LoCaTor SySTeMs typIcaLly inclUde a mobile RecEiVer and a transMItTer. The tranSmiTter can be couPleD to a taRgEt cONductOr, eIther By direCT electRical connEcTIon or tHRough inDUCtIon, tO provide a current sIGnAL on the target coNductoR. THE rECEivEr dEtects and pRoCesseS Signals REsULTIng FRom the EM field Generated at THe tArget cOnDucTOr as a rEsult Of THe cUrrent signaL. The Signal detEcted aT The line LOcator cAn be a cOntInuOus wAVe SiNusOiDAl sIGnAl pROviDed to the TaRgEt conDuctOR BY The tRanSmitTer.
ThE transmitter iS ofTen pHYsiCally SeparAted FrOm the ReceivEr, witH a Typical separatiOn diStance of sEveRaL meTeRs or iN Some caSes Up tO many kiLometerS. the TrANSMiTter couples the currEnT SIgNal, whose FrequeNCy CaN Be user seLeCteD froM A SelecTablE SeT of frequEncies, TO tHe Target cOnDuctor. thE frEquEncy oF The cUrrent Signal apPlied TO the target condUCtor can be refeRReD TO aS The aCtiVe locate freQuenCY. The TargET cOndUCtor gEneraTeS An em field at the active loCaTe freqUency In response to tHe current sIGNAl.
DifferEnt lOCaTIon methodologiEs and UndergrounD EnvironmEnts cAn call foR differenT ACtive freQueNciEs. THe tYPIcAl range of actiVE LocaTe FrequenCieS can be fRom SevEraL HeRtZ (for locatIon of the TaRgEt CoNduCtor oVEr separaTiOn dIsTanCes beTWeen thE tranSmitTeR aND reCeiver oF MaNY KiloMeTeRs) to 100 KHz Or More. SIgniFIcaNt radio Frequency IntERferEnCe On the EM Field detected By The receiveR cAn bE preseNT In the envIronment over this range. ThERefore, rEceIvers Of liNe locatioN syStems hAve OFten inCluded HighlY tUneD FIlterS TO pRecLuDe interferENCe fRom ouTsIde sOurces fRom affecting the meaSUreMent of signals At tHe deSIReD acTIvE LocAtE FreQUEncy from the targEt conductoR. THEsE filters caN Be tUnEd to recEive sigNals rESulting From EM fieLds at each Of The sELEctAble active Locate frEquencies ANd rejECt SignaLs rEsultiNg FroM EM fiElds at FReqUenciEs otheR tHan the ActivE lOcate freQuencies.
In line location sYstems, The siGnaL strength ParAMetEr determiNed fRom detectiOn oF thE EM fiEld PRovidEs a bASiS foR DerivEd quANtities of THe CurRENt Signal (i.e., the LINE cuRrent In tHE targeTed cOnductor), the positiON of the line locaTor rECEivEr rELatiVe To the center of tHe cOnDUCtor, the dEpTh of the condUctor froM tHE line LocatoR receiVer, and tHE InPUt to a pEak oR nuLl indicatOr (dEpENding on ThE oRIentatIon oF tHe elecTromagNEtic FIEld to which the detEctor IS SensiTIve). line lOcAtion sySTems Measure sigNal strength At one oR morE actiVe frequEnCies, alSo rEfErred to as mEAsurement ChannEls.
For dEtEctiOn oF cableS or pIPEs layIng iN a ConTinuous paTH (E.g., BUrIeD In a TrenCh or oCcUpyiNg an underGRound conDuiT ExtendiNg OveR SOme disTAnCE), An assumptiOn iS
 example, using pipe and c able locat ors.Und erg ro undpipe  and cable loc a tors  (sometimes termed lin e loc at o rs)h av e exi sted fo r  m a n y y ea rs  an da re  well  kn own. Li ne locator  sy st ems typicall y  i nclude a m obi le receiverand  a tra ns mit t er. T hetrans mitter can be  coupledto a targ e t condu c t or , ei ther by direct el e ct r ical connectio n or t hr o ug h ind uct ion, to pr ov ide a current si g n a l o n  the target c onductor. T h e r eceive rdet e cts an d pro ce s ses  signals re sult ing fromthe EM field g e nerated  at th e t arg et c o nd uc tor  a s  ar es ult ofthe curr en tsigna l. T h e s igna l d etec ted a t the line lo cat or c a n b e a c ontin uous  w ave s inusoi dal s ig nal provided to  the  target c ond uc tor  b y the transm itt er. 
The tr ansmitt e r i so f t en  physically separa te d fr om the r eceive r ,wi t h a typi ca l s epar a t ion d ista n ce  of seve ral me t er sor in s om e case suptomanyk ilom eters.  The tra nsmit t er couples the current signa l ,w h os e  fre que ncy can beuser sele cted fr oma  sele ctabl es et of frequencies, toth e targ et co nductor. Thefrequencyo f the curr ents ig n al applied tothe t arget cond u ctor can  be r eferredto as the a ctive lo cat e f req uen c y .The target co n d ucto rgenerat esan EM f iel d a t t heac tive loca te frequ en cy  i nres ponse to the c ur ren tsig nal.D iffere nt lo cati on  m e tho dologie s  a n d  und er gr ound  en vi ronme ntsc ancall fo r differe nta ctiv efr equenci es. The typic al  range ofac tiv e loca t e  frequen cies can be from severa l  Hertz(fo r loc atio n of thetar get co ndu c tor ov er sep arati on  di s t ances b et wee nthe transm i t ter  andre ceiv er of m any kilometers) to 100  kHz or more.  Si gnif i c an t r a di o  fr eq u enc y interference on  the EM fi el d  d etected by the  r eceiver  can be  pres e nt in t he enviro nment ove rthis r ang e. Therefo re, rece ivers ofl ine l o ca tionsys tems h av e o fteninclud e d h ighly  tuned  f ilters  to p re clude in terference from outside  sourc es fr omaffecting  th e  me asurement  ofsignals at  th e d esire d a c tiveloca t efre q uency  fro m  the targ e tcon d u ct or. These f i l t ers  canbet uned t o re ceive signals res u lting from EMfiel d s  at  ea c h of  t he selectableact iv e locate f re quencies an d reject  s i gnals  resul ting f rom EMf i el d s at f requ enc ies other  th an the act iv el ocatefreq ue ncies. 
In li n e lo c a tion systems, th e sig n a l str e ngt h par am eter de t ermi ned from d etection of  the E M fi eld p rovides  a  basis  fo rderived qu a ntities o f the  curren tsign al(i.e.,  the l ine c urre nt  in  the targ e t ed co nd u cto r),the p os itio n of thel ine loca tor receive rrel a t ive to th e center ofthe  cond u c tor, the d e ptho ft he co nducto r from  the li n e l oc ator re cei v e r, and th e input t o  ape ak o r null i nd icat or  (d ep ending on the o rientati on of th e electr oma g neti c  field  t o which thedetec to r  is sen s i tiv e). Lin e  lo cat ion  sys tem s me a sure signal strength atoneor mo r e a ctive  freq ue ncies, a l so r eferredt o as measurem ent channels.
F o r d e tect ion of  c ables orpip e s lay ingina co nti nuou s path (e.g . ,buri ed ina tr en ch  or occup yi ng an u n derg r oun d co nduit  e xt e nd ing ove r some d istan ce ), an ass u mptionis
 example,_using pipe_and cable locators. Underground_pipe and_cable_locators (sometimes_termed_line locators) have_existed for many_years and are well_known. Line locator_systems_typically include a mobile receiver and a transmitter. The transmitter can be coupled to_a_target conductor,_either_by_direct electrical connection or through_induction, to provide a current_signal on_the target conductor. The receiver detects and processes_signals_resulting from the_EM field generated at the target conductor as a_result of the current signal. The_signal detected at_the_line_locator can be a_continuous wave sinusoidal signal provided to_the target conductor by the transmitter.
The_transmitter is often physically separated from the_receiver, with a typical separation distance_of several meters or in_some cases_up to many kilometers. The_transmitter couples the_current signal,_whose frequency can_be user selected from a selectable_set of frequencies,_to the target conductor. The frequency_of_the current signal_applied_to_the target_conductor can be_referred_to as_the_active locate frequency. The target conductor_generates_an EM field at the active locate_frequency in response to_the_current signal.
Different location methodologies_and underground environments can call_for different active frequencies. The typical_range of_active locate_frequencies can be from several Hertz (for location of the target_conductor over separation distances between the_transmitter and receiver of_many kilometers)_to_100 kHz or_more._Significant radio_frequency interference on the EM field detected_by the_receiver can be present in the_environment over this range._Therefore,_receivers of line location systems have_often included highly tuned filters to_preclude interference from outside sources_from_affecting_the measurement of signals at_the desired active locate frequency from_the target conductor._These filters can be tuned to receive_signals_resulting from EM fields at each_of_the selectable active locate frequencies and_reject_signals_resulting from EM fields at_frequencies other than the active locate_frequencies.
In line location systems, the signal strength parameter determined_from detection of_the EM field provides a_basis_for_derived quantities of the current signal (i.e., the line current_in the_targeted conductor), the_position of the line locator receiver relative to the center_of the conductor, the depth of the_conductor from the line locator receiver, and the input to a_peak or null indicator (depending on the orientation_of the electromagnetic field to which the_detector is sensitive). Line_location_systems measure signal strength at one or_more_active_frequencies,_also referred to_as measurement channels.
For_detection of cables_or pipes_laying in a_continuous path_(e.g., buried in_a_trench or occupying an underground conduit extending over some distance), an assumption is