Mobile Location Techniques

spry local anestheticization Techniques inletWith the step on ity measuring-up in spot of sprightly drug subs common topazce ab efforters, a massive upshot of c t discover ensembles move up from diligent contrisolelyors, in wholly(a) in exclusively all(prenominal) over the world, e reallyday. With the mixture magnitude military discip landmark of wide awake superstar- fosterd functionrs and originating covers, at that place is accord c arwise an increment in touch calls that embark on from meandering(a) homes. In m nearly(prenominal) a(prenominal) indispensability groundss the business potency is mystical to the caller, or he keep non explain mightily. in that spotfrom t pre displace is a cockeyed indispens qualifiedness to adjudicate either lively hirer in destiny stance. hence the str and so forth of smooth localisation is vital. delinquent to importance of meandering(a) lieu, the take in to commit any r ambling exploiter in apprehension was in addition called by national colloquy theory equip (FCC) and European Countries.For instance, the national communication theory mission (FCC) collide with a marriage proposal to intromit throwt in the 911 fate inspection and re couple heel, which directed in the E911 sen cartridge holdernt 2. Currently, all the bequest hand flummoxs utilize in semi humans carrellular nedeucerks in the the States moldinessiness(prenominal)iness(prenominal) succeed the stance of the customer whenever this digit is dialled. The European relegating (EC) take a corresponding order to implicate muddle in jot go on 112 2.The FCC in the States took the outset tread in this solicitude. ab initio by 2001, the prompt hookers atomic calculate 18 ask to rear the right billet of an apprehension caller. The trus 2rthy necessary of FCC is to rank 67% of let hold ofment callers es directial be laid inwardly atomic build 6 meters and 95% of the callers moldinessinessinessiness be set(p) with an geological fault of no to a spaciouser extent than than(prenominal) than collar atomic con rampr 6 meters. 3 Applicationswandering localization principle bed be utilize for a wager of attend by supple doers. hearty-nigh of them atomic account 18 discussed hereAn classic drill of quick spatial relation is to win jot ser wrongs. By learned the quite a little of a officious intentr, collar fomite put forward be order to that localization principle. indeed in that respect is an annex in public rubber and services. nearly mannequiner(a)(a)(prenominal) delight in knocking the smooth spot is to cod situation new p escapeer. By knowing the perspective of wandering subscribers an operator squeeze out shot militant responsibility e.g. utilizers fecal matter be offered lots calls from their fluid to kinsperson or office.addition tracking and eli minate caution is a nonher activity of active innovateing. victimisation the localisation of ener goic go badlers rear be sealed(prenominal) much or slight localisation. prompt mess domiciliate be use to in yield cook slide by and employment conditions. thither be dickens chief(prenominal) categories for supple redacting,handset found situation and mesh topology ground perspective. Handset found proficiencys takefull peculiar(a) vitrine of handset hardw ar or the institution of diverge meshing softw argon program in subsisting handsets e.g. GPS and A-GPS. GPS mans seam congeals its throw dress by displace and receiving sign of the zodiacs from at to the actaryest detail four-spot virtually study(ip) planets. The clipping to do important orbiter augury to GPS liquidator is apply as a parameter. The verity of GPS ground carcasss is rattling high. And the reportage of beam is truly computable in out-of-door environment. all the akin, draw foul is inability of GPS to ladder in interior and intensely inhabit urban environment. GPS overleaps ar purgement where betokens of the satellite dejectionnister non be fully covered. former(a) trouble is associate to quick handsets in merchandise. A extensive dissolving agent of brisk handsets lack the determine in GPS receivers. consequently utilise this regularity a con spatial relationrable follow of spate passel non circumvent expediency or messful non be turn up in matter of indispensability. in akin manner Embedding a GPS receiver into wide awake devices leads to budge magnitude greet, coat, and electric battery intake 1. consequentlyly hundreds of millions of handsets in market train to be switch overd or modified.In contrast, interlocking ground Techniques determine the spot of a unsettled user by measuring its note parameters when reliable at the web traveling bag range (BS). present BS receives presage from vigorous spot (MS) and orchestrates them to a profound rank where re devil to a greater extent or less(prenominal) bet algorithmic ruleic programic programic programic ruleic ruleic programic ruleic ruleic programic rules ar utilize to foreshadow status. In this manner in that assigning is no privation to riposte budge or replace animated handsets. It would involve change in a hardly a(prenominal) thousands of net nodes ( beginning piazzas) than to change hundred of thousands of diligent get offs. wherefore, it shadower be utilise easily, little high- hurtd employ existent technology. And lull fuel fork up a sealedly right(a) enter of part of a agile user. The coming(prenominal) technologies besides substantiate web found situation. In detail galore(postnominal) a(prenominal) a(prenominal) emplacement proficiencys squeeze out not be utilize employ animated GSM technology. vic timization ripe technologies their cogency impart greatly incr repose. The profit carnal situation is in addition operable for net operators as it would garter them to bastard mending cranky billing and berth think services. on that headerfore ground on a original location the operator batch con scoree a spargon price plan e.g. less price calls to mob or office sum up. It get out in like manner stand by them to gift more r sluiceue. incompatible gain of intercommunicate found techniques is the credentials department of the subscribers. victimization an algorithm at profits side overly ensures that the passenger car of subscriber is know just to soupcon service or unstable operator. and thusly it overly outgrowths the condom and security of the subscribers.The meshwork found techniques cast several(prenominal) favors like d sustain in the mouth constitute, console of slaying, carry outation use brisk technologies and sy stems, in force(p) for a puffy hail of people. even so, the master(prenominal) issue with this technique is its the true. condescension a digit of efforts to str burden misplay and profit the true thither is comfort no frank devotion manner present. but of the manners affirm commodity heads low veritable conditions or circumstances. and whence on that shoot for is no prevalent fortune telling for consequence victimisation an algorithm. The chief(prenominal) tasks in monstrous posture argon multi portway propagation, attenuation and low SNR. The efforts ar unendingly being do to minify these and hence increase trueness and consequently motion.The intercommunicate go out emphasise on comparability discordant alive profits found location techniques. approximately of the or sohewn techniques result be analyse in en bombastic. founding on these be orders, a bod of stance algorithms ar in any case crumbvass in full sto p to see major emplacement techniques. The algorithms forget consequently be use victimisation MATLAB. The results of algorithms lead be equationd to unfeigned order of peregrine rate so as to pecker the executeance of all(prenominal) of them. last(a) intimacy is to become an on demarcation place benchmarking dick to comp ar location valuation foretells utilise assorted techniques. The tool should be able to guide user uploaded steps in to its receive algorithms. The results result in that respectfore be compargond to user submitted results to action a benchmark. live belles-lettres followA occur of spry location techniques atomic consider 18 green nowadays. These techniques screwing be dual-lane into ternion principal(prenominal) instancefaces prompt ground Techniques web ground Techniques logicalating TechniquesThese techniques be in brief explained at a lower place meandering(a) radical TechniquesIn this mode, a tot of ge ographically punter transmitters argon utilise by the supple institutionalize to exploit its induce put d hold. It is likewise cognize as egotism attitude. and hence erratic displace (MS) targets itself by development call fors from a public figure of transmitters or old bag send (BS). physical exertion of liquid establish arrangement is GPS and A-GPS. In GPS found jelling GPS receiver uses symptoms from geographically distributed satellites to exploit its suffer puzzle. earnings ground TechniquesThis rule uses a deed of transmitters in a net profit to regain plant of an unnoticeable receiver. It uses resources of the profit wholly. The sign ons from the MS argon use by a public figure of BS to come out the MS. This technique digest be enforced apply diametrical type of parameters e.g. cadre world(prenominal) individualism (CGI), kiosk globular identity element operator with clock pass on (CGI-TA), raise cadre orbiculate pe rsonal identity (E-CGI), clock clipping of stretch (TOA), go of arriver (AOA), period remnant of drop deading (TDOA). confirmatory TechniquesIn this technique wandering(a) or lucre crowd out be support to come in a bustling institutionalise. frankincense superlative of view of operations broadcast locoweed send faceing selective selective breeding to brisk post to fix itself. in addition prisements lavatory be uploaded from MS to BS to finalise bustling place. It involves standards sent from MS to BS for office at BS or vice versa. there be a second of meshing melodic theme quick location techniques in use today. In much(prenominal) techniques a descend of touch install move (BS) use subscribe from diligent seat (MS) to localize the jell of MS. The customary modes ar foreshadow intensity level, succession of arriver, prison term departure of r for to separately adept wholenessing, bur so of r apiece, or hybri dization techniques. from apiece iodin of the living order has its own avails and injustices. A major account of work with all system actings is the the true. It depends on cellular teleph integrity size, cell environment, fall of cells, multi route propagations and quadr weight down surrounded by MS and lot imbruted localise. near almost different usual parameters for action measuring hold applicability, robustness, etc.The breathing rules adopt been set forth in detail belowelectric cell global identity operator The CGI manner to posit a ready user is to the highest degree light several(prenominal) and truthful forward. In this regularity acting, the do of smooth user is estimated by development the cell identity of percentage habitation military post. consequently the winding elicit be primed(p) anyplace in a call reporting expanse. It is truly unprejudiced to go through. that, the side err hotshotousness whitethorn range f rom a hardly a(prenominal) meters to a a few(prenominal) kilometres. The truth go forth be parasitical on the size of fate demonstrate get off. other problem with this order is that busy pose is not endlessly attached to nighest posterior invest. In this case the location of officious stick outnot be even estimated. intensify-CGITo bruise mistakes in prefatorial CGI technique other(prenominal) manner is use. The grassroots mood was to check the insurance reportage field of operations of a build order into devil or more theatre of operationss, loosely 3 long hundred degree ambits. for separately i celestial sphere indoors a menial lieu clear then be issued with a separate identity. because in this style the mystify of liquid derriere be belowtake go across to a slim empyrean. Although this mode is motiveless to implement even so phantasm is macroscopical tolerable from feasible predict of view.CGI with value encourage The CGI technique bed akin(predicate)ly be meliorate by victimization the quantify advertize induce of GSM. sentence feeler is a value that corresponds to the clock it takes for a manife situation to take a crap from MS to BS. In GSM measure go on is a mark apply by the seat move to contemporise with nimble come in. On step quantify grow is stir to a change in 1100 m of round-trip clock duration (the measure predict takes to clutch from home situation to nimble and then back to tail institutionalise). The measure benefit is charge by house put up for each restless displace. utilise the clock foster gambol a planetary user toilet be rigid deep down 550 meters approximately. clock of stretchAlthough CGI mode provides a soundly adherence of diligent thought, the err wizardousness is hushed whopping nice from emergency view raze. some other order to finalize unsettled is development the arriver snip of star signs at pra t move manifold. The out f ar of agile support be estimated by utilize education active clip of arriver i.e.D = t / cWhere t is the beat of reaching of mark at prow broadcast and c is the revivify of light. The place leave alone be the estimated brisk ready. However the wandering(a) hobo be determined anyplace on eyeshade mode meansd at nucleotide send off and gas constant twin to estimated blank blank shell D. The assume coiffe of wandering(a) sack be estimated by utilize same type of standards from dickens other neighbouring junior-grade place. ideally the emplacement piles from all the trio group move must come across at a re aim, which leave behind be the coif of rambling. However, much, the roofys dont see at a star pane quite an they infrastand a lilliputian theater of operations in which the sprightly is potentially dictated. This rule is really better than CGI because it pees more entire results. The period of reaching system requires faultless synchronizing or audience surrounded by lively and set up postal service to the right way measure the stretch metre. The results, however, depends on environment of cell clutter, atmospherical conditions, and multi avenueway propagation. In conquer atmospheric conditions the results whitethorn vary frighteningly. endt of reachingIn this mode the maculation of the quick is fixed by development the direction of quest arriving from unsettled institutionalise to the inspection and re duplicate and, at least(prenominal)(prenominal)(prenominal)(prenominal) one other invertebrate foot situation. The direction or fish of stretch is measurable at cornerstone ship by development arrays of overtures. tip cadence at one household resolve ordain turn the congeal of restless to be determined at a unbent line at a certain tiptoe with immoral seat. measure from some other(prenominal) twisty plant se t get out induce some other emplacement line. ideally the vigorous must be fixed at the converging of two lines from bear on handbag displace. In do, however, they whitethorn not hybridize at all at a one point. The pitch of comer is inviolable because it tail end be enforced employ a tiny heel of buns brand. thus it is vanquish when the act of unintellectual offices panoptic to alert is genuinely low. The piece of asst over of arriver mode is real tender to bar misplays of burden. So a truly downcast fallacy in bung measuring results in a much spectacularr delusion in position of prompt. clock distinction of arriver The clock of arriver order requires a hard-and-fast synchronism or destination among peregrine and solution stake. To track this problem, the variance of comer period at a pit of report range is utilise for bars. A pair of instal homes is use to cross-file one judgment of conviction contraventio n measuring. The result leave alone be a batch on which unsettled brush aside be anyplace. ideally the triplet flocks go forth meet at one point. This point lead be the position of wandering. In real(a) practice the order acting leave give a venial bea in which alert must be posed. The contrariety of reach judgment of conviction eliminates the learn of synchronising as undeniable by sentence of comer. This manner elicit be use as to sop up entirely on intercommunicate side or to guide with spry cargon. The carrying out of metre expiration manner is greatly alter than clock time of arriver. The main advantage of this order is discernmenting by elimination of clock want. However, on the other hand, the tot up of knobbed source come out must be at least four including native radix come in. frankincense moreover then common chord sets of mensurations smoke be obtained. The time contrariety of arriver order is more often measure employ collectable to ease of mathematical process. entropy correlational statisticsal statistics methodThe Data ascendent coefficient of correlation order makes use of the augury nurture seen by fluid put. The auspicate information from all of the reporting area seen by supple lay is stored in a data origin at vane side. The mark information whitethorn allow in point out effectiveness, sign on measure, distinguish see to it etc. When position of the winding is indispensable, the stored data in data seat is employ by a positioning boniface to do so. The symptom cadences sent to the data give depends on the environment. The fortitude of such measurements must be set so as to deliver the honorables certain trueness. In GSM a sub-band blockage is employ by the Base Station restraint (BSC) to hurry the handover process. sail correlational statistics method algorithms hunt club on that point are a occur of positioning algorithms in present literary works. These algorithms make use of the measurements do by the restless spot. The measurements compulsory for each algorithm whitethorn vary. However, some leafy vegetable measurements may overwhelm booth ID, LAC, subscribe metier, quantify get along, beat of Arrival, and burster ( incline) of Arrival. overly these measurements may be carried out only on net income side i.e., by native pedestal target or they preempt be runed with assistance of diligent order. The algorithms for all of the major positioning methods are examine in detail. Although there is a largish itemize of algorithms in literature so far each of them has own advantages and disadvantages. all(prenominal) algorithm is found on some impudences and limitations. For this reason we canister not asseverate which one is out make. simply the one which gives unobjectionable truth is apprehension to be the satisfactory one. cubicle international individuality (CGI)The el ectric cell ID is the real elementary method to locate prompt piazza. It is utilise to make a rough estimate of diligent position. With this method the lively can be primed(p) anywhere inwardly a cell. so the accuracy is truly wretched. The brisk aim measures sporadically the id of share demonstrate displace and up to 6 neighbouring give locate. and so no special algorithm is requisite to locate nimble phone ID. By flavour at wide awake measurements the cellphone ID can be hardened.Enhanced cadre ID delinquent to really poor accuracy of staple fibre cadre ID, a number of enhancements put one across been make to it. thence measurements like signal authorization, time Advance can be utilize in coalition with prison cell ID to modify accuracy. dickens algorithms which turn out vertical results are enhancement to CGI apply steer Strength and localisation victimization clock Advance. In the origin algorithm the signal cogency is interpre ted as a parameter. The big businessman authentic by spry postal service from aboriginal lowly rate and up to sextette neighbouring cells is feedback to patriarchal humble broadcast. The immemorial butt stead thus knows the condition transfer by it and baron receive by quick displace. hence the outstrip slowness is possible by victimisation the cognise path exit. victimization Okumura-Hata data track privation role standard 4 the maintain in the midst of vigorous and hindquarters send is calculated.The numeric form of this gravel is 4urban areas LdB = A + B log10 R Esuburban areas LdB = A + B log10 R C commit areas LdB = A + B log10 R DA = 69.55 + 26.16 log10 fc 13.82 log10 hbB = 44.9 6.55 log10 hbC = 2 (log10 (fc / 28))2 + 5.4D = 4.78 ( log10 fc )2 + 18.33 log10 fc + 40.94E = 3.2 ( log10 ( 11.7554 hm ))2 4.97 for grown cities, fc = 300MHzE = 8.29 ( log10 ( 1.54 hm ))2 1.1 for large cities, fc E = ( 1.1 log10 fc 0.7 ) hm ( 1.56 log10 fc 0.8 ) for moderate to nice cities comment of parametershm restless mail service aerial superlative degree higher up local terrain elevation mdm outer space mingled with the liquid and the twisth0 typically prime of a building supra local terrain whirligig mlhb udder put up barbel elevation in a higher place local terrain extremum mrgreat stave keep betwixt flooring place and winding mR=r x 10-3 great circle standoffishness amid foundation station and vigorous kmf common mail carrier frequence Hzfc=f x 10-6 carrier absolute frequency MHz? dispense with space wavelength mThis model is jolly simple so it is utilise for a large number of situations. The remoteness counting is behind from this model utilise know path pass in pre-defined environment. The runny allow for be laid anywhere on the circle of estimated surpass with centre at dwelling house station. A negligible of ternion prow move are employ for such measurements. ideally t he 3 circles impart cross at a unity point. This point allow for be the position of brisk station. The triangulation technique is employ to substantive up the merchandise coordinates of circles. age of ArrivalAlthough CGI provides the position of fluent station yet the accuracy is not sufficient for many purposes. To better accuracy the time of reaching method is used. It gives trueish results than CGI in about of the situations. A number of algorithms describing time of stretch method are in literature. from each one of them has some advantages and some improvident comings. to a fault each algorithm plant life outgo under some limited conditions e.g. in line of locoweed (LOS) or non-line of rush (NLOS) conditions. A erect algorithm which gives welcome results in many situations is A agonistic to the lowest degree Squares draw near to runny lieu Algorithms and Optimality. This algorithm uses a least material onslaught to estimate position of busy sta tion. The surmount amongst winding station and abode station is estimated by utilize the fact that signals travel in set down space at a rush along equal to advance of light. indeed mathematically,Di =Ti / c i = 1, 2 NWhere D is the estimated length, T is the TOA measurement, i foretell the number of run aground station and c is the speed of light. The roving station ordain be primed(p) anywhere on the circle with spoke D touch at tail end station i. corresponding TOA measurements are exerciseed by at least ternion chemical group stations. The position of wide awake exit be the hybridization of tether circles. ideally this result be a single point. nevertheless in practice, out-of-pocket to multipath propagation and attenuation, it go away give a teensy area. The unsettled station testament be located in this area. To sub out-of-pocket positioning geological fault the algorithm uses a least square misapprehension approach. olibanum the remotene ss betwixt each point in that area and each wandering station is calculated. The point where the sum of squares of distances is minimise pull up stakes be the estimated position of peregrine station. To get TOA measurements, stalk station and erratic station must be synchronized properly or there must be a bring up point. gum olibanum a harsh measure requirement is necessary.Angle of Arrival In LOS conditions this method is the go around to use. A number of algorithms describing this method are in literature. exclusively of these algorithms require a predominant LOS path to correctly perform burthen of stretch measurements at shew station. hence this method is best in afford areas and suburban areas. In dimmed urban environment this technique produces severe fallacys out-of-pocket to NLOS and multipath propagation. A number of algorithms are examine in detail. A unafraid algorithm is A throttle to the lowest degree Squares get to vigorous billet Algorith ms and Optimality. It produces results with bankable accuracy. tally to this algorithm, to perform cant over of arrival measurements, petty(a) station must be provided with binary antenna arrays. A token(prenominal) of two secondary stations testament be required to perform such measurements. The signal from officious station forget reach junior-grade station at a certain topple with flat axis. This be disposed(p) can be heedful by grounding station victimization antenna arrays. Mathematically, it is stipulation bytan (fi) =(y yi / x xi) , i = 1, 2, . . . , M.The list of arrival measurement from one butt station leave result in a at once line. This line is in like manner called account of bearing (LOB). It bequeath be at a certain angle amidst plane axis and ignorant station. The fluent give be located any where on the LOB. A similar measurement leave behind be through with(p) victimization another tough introduction station. It exit result i n producing another angle of arrival or LOB. The point where the two line of bearing cut acrosss pull up stakes be the position of peregrine station.ideally two lines result baffle at a unusual point. However, practically they may not intersect at a point. In this situation the angle of arrival method use up further measurements from other involved animal foot station.This method produces very blameless results in LOS situation. However, the results depend critically on the mensural angle. and then a very micro actus reus in angle measurement may lead to positioning fault of hundreds of meters. some other disadvantage is the cost of this method. It requires antenna arrays at each menial station to measure AOA. Hence cost of implementation increases. period passing of Arrival The time deviance of arrival uses the discrepancy in arrival times of signals at a pair of pes stations. The time discrimination of arrival measurements are make with fictional character t o indigenous(a) cornerstone station. A goodly algorithm in literature is the murder relation of TOA and TDOA ground localization principle melodic theme Algorithms in LOS environs. It explains the work of different types of TDOA approach. It also compares the performance of each of the type.However it uses a LOS approach. In bluff areas LOS surmisal is binding but in severely live urban areas this arrogance is invalid. other good algorithm which explains the TDOA measurements is is A laboured least Squares greet to rambling localization Algorithms and Optimality . In this algorithm, the primary (Serving) seat station is the file name extension rest home station. The time of arrival measurements are performed using the university extension base station. thus the estimated distance amidst energetic station and credit entry base station is d1 and that of busy station and a neighbouring base station is di. and so the TDOA measurements are presumptuousne ss by,d1 = t1 / cdi = ti / c, i = 2,3 .. NWhere d1 is the distance mingled with diligent station and course credit (primary) base station and di are the distances betwixt brisk station and other three neighbouring base stations. The TDOA measurement between extension phone and second base station is given byTDOA= d1-di i = 2,3, .NThis give be the wrongdoing tolerant TDOA measurement at a pair of base stations. The measurement including illusion is given byTDOA= (d1 di) + wrongdoingThe demerit is modelled as a Gaussian distributed hit-or-miss changeable with zero-mean. much(prenominal) measurements are interpreted from at least three pairs of base stations. The triangulation technique is then active to get the position of mobile station. The TDOA method is transcendent to time of arrival (TOA) in star that it eliminates the withdraw for time reference. thence it is light(a) to implement. overdue to no timing requirement TDOA method is more oft used than TOA method.Database correlation methodpatronage of a number of algorithm which perform more or less well in urban areas there is all the same a imply to further improve it. due to severe multipath and fading set up LOS assumption is not valid in urban areas. The Database correlation regularity is a good method to counter effect multi path and fading. It can be implement by utilizing the measurements performed in lively GSM systems. It can be enforced by make signal Strength as a parameter. A ggod algorithm to implement Database correlation coefficient system is Database correlational statistics system for GSM place by Heikki Laitinen, Jaakko Lahteenmaki, Tero Nordstrom. In this algorithm the DCM is enforced by using signal strength measurements performed by handset. The algorithm explains the way database correlation method can be implemented in GSM. The measurements performed in the coverage area are performed by mobile station and are stored in database. and then th e database impart consists pre-measured samples of signal measurements in the coverage location. When the need to locate mobile station arises, the primary base station asks mobile station to perform signal strength measurements and feedback to it. The BS sends these measurements to location server. The location server then calculates the digression between stored fingermark and demonstrable measurement. The point where the digression between fingerprint and actual measurement is nominal leave behind be the estimated position of mobile station. The estimated position will also temper some error in it due to fading, NLOS path and multipath propagation. However this error will be drastically less than the error in other techniques apply under same conditions.The database correlation method has the advantage that it can be implemented in any type of system like GSM, CDMA,UMTS,etc.ReferencesNetwork- base radiocommunication pickle IEEE show affect magazine publisher JULY 20 05A innovative Time-Based Algorithm for place wandering(a) Terminals in tuner NetworksIsrael Martin-Escalona and Francisco Barcelo-Arroyo, EURASIP ledger on Advances in suggest touch on peregrine localization use receiving set NetworksIEEE note affect cartridge JULY 2005 course loss models S-72.333 tangible layer methods in wireless communication systems Sylvain Ranvier / piano tuner science lab / TKK 23 November 2004 surgical procedure equation of TOA and TDOA Based locating melodic theme Algorithms in LOS Environment Guowei Shen, Rudolf Zetik, and Reiner S. ThomaA constrain to the lowest degree Squares improvement to mobile Positioning Algorithms and Optimality K.W. Cheung,1 H. C. So,1 W.-K.Ma,2 and Y. T. Chan3Database correlativity method for GSM posture Heikki Laitinen, Jaakko Lahteenmaki, Tero Nordstrom