GB2404532A

GB2404532A - Method and system for displaying scaled, precise maps on personal navigational aids

Info

Publication number: GB2404532A
Application number: GB0423967A
Authority: GB
Inventors: Satoshi Odamura
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2001-05-29
Filing date: 2002-05-29
Publication date: 2005-02-02
Anticipated expiration: 2022-05-29
Also published as: GB0423967D0; GB2404532B

Abstract

The invention provides for a system and method in which the global position of a mobile terminal is estimated from GPS (global positioning system) signals transmitted from a number of GPS satellites and received by the mobile terminal. The degree of precision of the estimated global position is determined and the size, or scale of an area to be displayed is determined according to the degree of precision, and a map of the area of the determined size is generated according to the global position of the mobile terminal, and displayed on the mobile terminal. In a preferred embodiment, a number of GPS satellites whose transmissions are higher than a predetermined SNR may be selected from which to receive signals.

Description

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2 METHOD AND SYSTEM FOR DISPLAYING MAP 6 The present invention relates generally to global positioning systems, 7 and more specifically to a method and system for display maps for 8 personal narlgational aid, The global positiorung system, or GPS, ho recently teem used 11 extensively for application to wirier mobile terminals to serve as a perusal 12 navigational aid. According to the current method, the mobile tenrdnal 13 receives signals from GPS satellites and deterrnmes its global position by 4 processing the receivedugnale and transmits a request via a mobile communications network to a map sewer for a map. The request contains 16 information as to Me mobile's globe1 position and We scale of the map 0.e., v Me else of Me geographical area to be displayed). reeporee, Me map 8 server produces a map of the requested scale and communicates this map to 19 Me mobile terminal for display. However, due to Me presence of hindrances in due paw of signals from line-of-siht GPS satellites, Me received signals 21 may be disrupted or may lose critical data, particularly when the user is I moving around built-up area. As a result, Me user may not be eatkfbd win 23 the displayed map, and kansrnih a request again to the map server to alter 24 Me scale of Me map. The process will be repeated until Me displayed map meek Me users satiefachom However, this Lion 0.

1 Therefore, ere ets a need for eliminaUng e nanual process of 2 determining the scale of a map displayed on a wireless mobile terminal.

3 According to a fleet aspect of the precut invention, there is prodded a 4 method of display a map on a mobile terminal, comprising Me of esUmaNng a global poeidon of Me mobile terminal from signals knitted 6 from a plurality of GPS (global positioning system) satellites and received by 7 & mobile terms demands a degree oppression of Me estimated global 8 pounds of Me mobile term.Ir, dekmhling a size of an area to be displayed 9 according to the degree of precision, genera map of We area of the 0 defamed adze according to the global position of Me mobile Amino and displays Me map on the mobile belaaL 22 According to a second aspect, Me precut invention provides a mobile 3 communication system comprising communications networl, a renter eckd to Me network for estimating a global petition mom rsodred GPS dgnale, and a mobile Arm for receiving GPS sigmas fmm GPS satellite.

16 ant tranemittg Me received firs Bifocals to the server Canon via He 7 aommuniceHon' network to cause Me server station to dee Me Tubal 18 poison of Me mobile terminal The server determines a degree of precision 19 of Me estimated globalpodHon of Me mobile tell and deknrdnes Me size of an area to be displayed on the mobile teminU according to Me degree 21 of preys, generate' a map of Me area of Me determined me aag to 22 Me global poeidon of the mobile to and communicates Me generated map to lbe mobile to 24 According to a Gird aspect, Me preset invention provides a mobile comawnicadon system comply a communication. network, a mobile 26 Army for receiving GPS signals from GPS satellite, and a server. The 1 mobile tns1 esi - its globalpoidon from Me revved GPS sl., 2 den a degree of precinct We estimated global position of Me 3 mobile denial and deeming the line of an area to be displayed on lhe 4 mobile seminal according to Me degree of predaion. Prom Me mobile terminal a server receives informadon as Me globes position of Me mobile 6 terminal and the size of Me map via Me network, generates map of Me area of Me according to Me received information and communkate Me map 8 to Me mobile terminal via the network.

It is therefore an advantage of the present invention that a method and 11 system for automatically displaying a map of appropriate scale on a mobile 12 terminal-can be provided.

13 The invention also advantageously allows for the determination of a 14 degree of precision of estimated mobile position and determining the scale of a map according to the determined degree of precision.

7 The present invention Will be described in detail fury with reference 18 to tile follows drawln, in with; 19 Fig. 1 a block telegram of a aommunicadon system according to a ED ant embodiment of the present invention; 21 E6g. 21e a flowchart of Me operadan of a server controller in Me GPS 22 station of Fig. 1 accrdg to the flat embodiment of We precut invent/an; 23 Figs. 3A and 3B are exemplary illustrations of constellatory poundage 24 of lineofsig}tt GPS satellites; Pig. 4 is a flown of modeled form of We map Cling ibrouHne 26 ofEg.2; 1 Pig. 5 is a flowchart of a furler modification of Me map scaling 2 eubroudne of Fig. 2, 3 Fig. 6 is a bloc' diagram of a communication system accord to a 4 second embodiment of We present nvenn, Fig. 7 is a flowchart of Me operation of Me mobile terminal of Fig. 6; 6 and 7 Fig. 8 i' a flowchart of the operation of a server of Plg. 1 when mobile terminal is in a mod velure.

In Pig. 1, Mere is Owns communication 6 ably a 11 embodiment of be precut invent) - . The communication eyetem is 12 comprised of a Communicated network 3 why a placid - em 13 base stations 2 and a GPS (global poeidoninE' system) st0&don 4 are connected.

14 A wer mobile tenninal 1 operates win a radio troeiver 11 to set up a wlre. link to a nearby base stat A commurucation controller 12 16 performs communication control of Me terminal 1 win Me base stain V accord to the known protocol. A central pncessk g unit (CPU) receives 18 signals from Me controller 12 and saves Me signals in memory 14 to display 19 a map on display panel 15. User insbuctione are entered through a keypad 16 to be CPU 13. A GPS antenna 17 Provided to recvels Tom GPS 21 satellite' end a GPS processor 18 processe Me received GPS dgneb. The 22 processed 6igna]5 are supplied to the CPU. In a first embodiment of the 23 present invention be CPU produces Preston GPS s - 1 from Me signab 26 directly rived from the satellites and supplemental GPS dad obtained from be C;PS stadaó 4.

1 GPS etat,'on 4 is comprised of a GPS anteTua 21, a GPS receiYer 22, a 2 position finder server 23 and a map server 24. Bow servers 23 and 24 are 3 connected by a bus system to a server controller 25, which is in turn 4 connected to Me communications network 3 to exchange signals win We mobile termir1 1 via one of the base stations 2. The GPS receiver 22 6 processes signals detected by the GPS antenna 21 and produces Me 7 supplemental GPS data by using the signals supplied from the GPS antenna 21 and the signals received from Me mobile terminal 1.

9 The operation of the server controller 25 according to Me first embodiment will be explained below with reference to the flowchart of Fig. 2.

11 Initially, the mobile terminal sends a request to the server controller 2$ 12 for supplemental data. In response to the request from the mobile terminal 1 13 (step 201), the server controller 25 establishes a link between Me mobile 4 terminal and the position finder server 23 and retrieves supplemental data from the server 23, indicating the identification numbers of lineotsitht GPS 16 satellites, and tranmite it to the mobile terminal (steep 202). On the other 17 hand, the mobile terminal 1 is receiving GPS BialB from the lineof- sight 18 GPS satellites. Using the supplemental data from the server controller and 19 the received GPS signals, Me mobile tenninal 1 calculates a peudorange and to transmits it as a precision GPS signal to the GPS station 4 via the al communications network 3.

22 When Me server controller 25 receives the precision GPS signal from Z3 We mobile tell 1 (step 203), it instruct, Me position finder Bethel 23 to 24 determine tile global position of the moWe terminal by using Me precision GPS signal (step 204). Furler, Me seater controller UBeB the precision GPS signal to detemune the constellatoy positions of line-ofsight GPS satellie from which Me mobile terminal has actually received We GPS signals and 3 perform map scaling subroutine 200.

4 Me map scaling subroutine, Me server controller uses Me position dam of the satellites and analyzes it to detennine Me constellatory positions 6 of Me satellites, According to their constellatory posidor, the server 7 controller divides the satellites into a group of four sectors, or quadrants in 8 Me constellation and determines Me number of quadrants in whim the line 9 of-sight GPS eatelli are currency located as a measure of the degree of lo precision of estimated position of the mobile termbnal.

11 Pig. 3A shows one example of constellatory positions of lineof-eight 2 GPS satedlite where the solid dots represent GPS satellites. In the lIhstrated 13 example, Me satellites are distributed relatively equally among the four 14 quadrants of Me constellation, and hence Me number of quadrants where the lof-sigiht satellites edit four. Note Mat Me center of the circles 16 corresponds to Me position where Me mobile user terminal is located. 1h Fig. 17 3B, the line-of-sight GPS satellites are shown unequally distributed possibly 8 due to hindrance by terrain or building structure SO that only two satellites 19 are in line of sight in each of Me fibs (northeast) and fours (outh- east) quadrant to Me mobile terminal and no satellites are h line of Bight in Me 21 second and Gird quadrants. In Me case of Pig. 3B, the number of quadrant 22 containing line-of-sight GPS satellite is two.

23 Retuming to Pig. 2, Me map scaling subroutine 200 begins win 24 decision step 205 to make a Grecian as to whether the lineof-sight GPS satellitm Midst in an Me four quadrants. his is Me case, flow brand out A '

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1 to step 206 to select a 50-meter x 50-metier square area and proceed to the 2 end of Me subroutine. If decision at step 205 is negative, flow proceeds to 3 step 207 to determine if the line-of-sitht satellites only exist in Free 4 quadrants. If so, a 100-meter x 100.meter square area selected (step 208). If the decision at step 207 is negative, flow proceeds to step 209 to determine if 6 the line-of-sit satellites only exist in two quadrant. If so, a 200- mete: x 7 200-meter square area is selected (stop 210). If the decision at step 209 is 8 negative, a 500-mer x 500-meter square area is selected (step 211).

9 When the execution of subroutine 200 ends, flow proceeds to step 212 in which the server controller informs the map Server 24 of the current 11 position of Me mobile terminal (as deternuned at step 704) and instructs it to l2 send map data of the selected area to Me wer terminal. On receiving the map 13 data, the user terrunal displays a map on its display panel.

4 In a modified embodiment of the present invention, Instead of Me constellatory positions of line of"sight GPS satellite., the signal-to noise ratio 16 (SNR) of Me GPS seal and We number of GPS satellites transmitting signab 17 of relatively him SNR are used Grille decisions as to the Resale of the map.

18 The modified map scaling subroutine 300 is shown in Pig. 4.

19 Fig 4, the subroutine 300 begins win step 401 which determines whether there are Tree or more satellites which are transmitting GPS so 21 with SNR higher than 35 do. If me den ision is affirmadve, Row proceeds to 22 step 402 to select a 50 meter x 50-meter square area. If Me decision is 23 negative at step 401, How proceeds to step 403 to determine whet there are 24 only two Satellites whose SNR value is greater lhan 35 dB. If so, flow proceeds from step 403 to step 404 to determine whether there is at least one

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1 satellite whose SNR value i in the range between 25 dB and 35 dB. If die is 2 the case, flow proceeds from step 404 to step 405 to select a 100-meter x 100 3 meter square area. If the decision at step 403 or step 404 is negative, DOW proceeds to Step 406 to determine whether there is at least one satellite whose SNR value is greater Man 35 dB. If BO, flow proceeds to Step 407 to make a 6 fewer decision as to whey Were is at least one satellite whose Shy ratio 7 in the range between 25 dB and 35 dB. If this is the case, Dow proceeds from 8 step 407 to step 408 to select a 200-meber x 200-meter square area, If We 9 decision at step 406 or step 407 negative, How proceeds to step 409 to select a 500-melr x 5W-met squeze area.

1 Pig. S shows a furler medication of We map scaling subroutine, 12 which begins with sup 501 which determines whether the linef-sight GPS 13 satellites exist in all four quadrants of the constellation. If so, flow proceeds 4 to step 502 to set a variable D to 1, and if not, flow branches out to step EiO3 to determine if We line-of-sight satellites edit anly in Free quadrants it' so, 16 flow proceeds to step 504 to set the variable D to 2, and if not, flow proceeds 17 to step 505 to determine if there are only pro quadrants in whim We lineof 18 Bight satellites elide. H80, flow proceeds to step 506 to set We variable D to 3.

19 One, flow proceeds to step 507 to set We variable D to 4.

Following We execution of each of eta 50Q' 504, 506, 507, flow 21 proceeds to step 508 to deterrune if Were are at least three satellites e 22 SNR value is higher than 35 dB. If so, a variable S is set to 1 at step 509.

23 Otherwise, flow proceeds from step 508 to step 510 determine if there axe two 26 satellites whose SRvdue is higher hand dB. It so, a Bother decision is made at step 511 as to whether Mere is at least one satellite whose SNR value 9 -

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1 is in Me range between 25 dB and 35 dB. If 80, flow proceeds to step 512 to 2 set We variable S to 2, If Me decision at step 510 or 511 is negative, a fur - 3 decision is made at step 513 as to whether there is at least one satellite whose STAR value is higher than 35 dB, and if so, flow proceeds to step 514 to determine if there is at least one satellite whose SNUB value is in the range 6 between 25 dB and 35 dB. If the decision affirmative at step 514, die 7 variable S is set to 3 at step 515. If Me decision at step 513 or 514 is negative, 8 the variable S is set equal to 4 at stop 516. Following Me execution of each of 9 steps 509, 512, 515 and 516, flow proceeds to decision stop 517 to compare Me to variables D and S with one another.

71 If D e S -1, 50-meter x 50-nneterequare area is selected (amp 518). HD 12 = S = 2, 100-meter x 100-meter square area is selected (step 519). If D - S - 3, 13 200-meter x OO-meber square area is selected (step 520). If D = S _ 4, 400 24 meter x 400-meter Square area is selected (step 521). If D is not equal to S. an intermediate area is selected depending on their relative values (Beep 522). If 6 D. 1 and S = 2, for example, an area of 75-r by 75-meter square 7 eelect.

18 the embodiments described above, Me mop scaling subroutine 19 performed by Me GUS station 4. The map scaling subroutine can be JO performed by the user's mobile terming 1 in a conmunicaNcm system 21 shown in Fig. 6.

22 Pig. 6, Me mobile terminal 1 establishes a wireless link with one of Me base station 2 "d establishes a co=ecHon to Me map serve via Me 26 communications network 3. Ibe operation of the mobile tea 11 proceeds according to the flowchart of Fig. 7, in which the routine begins win step 701 1 to receive GPS signals and procees the received signals to produce a precision 2 GPS signal and estimate the global position of Me mobile tenninal using the 3 precision GPS eigna1. At step 702, We mobile terminal performs Me map 4 &caring subroutine of either Pig. 2, 4 or 5 to detente Me degree of precision of Me estimated global position of Me mobile terminal and select an area size.

6 At step 703, the mobile terminal sends a request indicating &e global position 7 of the mobile terminal and the selected area size to the map server 5. Map 8 server 5 generates a map of a geographic area according to Me informed g global Poseidon and scales the map according to the selected area size and transmits visual information containing the generated map to Me mobile 11 terminal 1. Mobile terminal 1 thus obtains a map of the area at the selected 12 scale where Me mobile terminal is in. At step 704, the obtained map is Men 13 displayed on the mobile terminal.

14 fig. 8 illustrat- flowchart of the operation of Me server controller of Pig 1 according to another embodiment of Me preset invention. This 16 embodiment is particularly useful for applications where the war is driving 17 an automobile.

18 Mobile terminal 1 is located in a moving vehicle. The terminal initially 19 receives signals from Me GPS satellites ant processes Me signals to produce precision GPS signal without supplemental data from Me network and 21 transmits a request to Me network containing the precision GPS signal for a 22 map of Me area where the vehicle my around.

23 Id response to the request from Me mobile terminal (step 801), Me GPS 24 Station 5 processes the precision GPS signal contained in Me request and determines Me initial position of Me moving vehicle (step 802). Then, Me

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1 touNne prod to sup 803 to wait a predetermined amount of e. At step 2 804, the (I station obtains Me most recet*preon GPS signal from 3 mobile terminal and determine. subsequent Rehire poked At step 80S, 4 We initial and subsequent position of Me mobile terming are wed to calculate its Speed of the vile. The cat abed Speed is den compared, at 6 8p 806, with a preset value. If the calculated speed is lower Man Me preset 7 value, map daof normal scale i generated according to mat mode of 8 operation and Me map date trotted to the mobile terminal (Blip 807).

9 Ate calculated speed is hid Man Me prom vane, a map of wide area is gestated accords, to Me detected poser of Me vehicle and Me 11 information of do map is - mode for display (my 12 808).

3 While Me embliments of F - . 2 anal 8 are based on Me known 14 network drivaltan and Me standalone system, reecvely, Me present invention could en be as well Implemented the known network 16 a-fat system in Chide obal position of Me mobile tong is esffmahid 17 by mobile terminal after receding GPS dgnab from a GPS server.

Claims

1. A method of displaying a map on a mobile terminal, comprising the steps of: a) estimating a global position of said mobile terminal from signals transmitted from a plurality of GPS (global positioning system) satellites and received by said mobile terminal; b) determining, from said transmitted signals, a number of GPS satellites whose transmissions are higher than a predetermined signal-to-noise ratio and determining a degree of precision of the estimated global position of said mobile terminal from said determined number of GPS satellites; c) determining a size of an area to be displayed based on the determined degree of precision; d) generating a map of said area of said determined size according to said global position of said mobile terminal; and e) displaying said map on said mobile terminal.

2. A method according to Claim 1, wherein step (a) comprises the steps of: receiving, at said mobile terminal, signals transmitted from said GPS satellites; receiving, at a GPS station, signals transmitted from said GPS satellites, producing therefrom supplemental GPS data and transmitting the supplemental GPS data to the mobile terminal; producing, at said mobile terminal, a precision GPS signal by using the signals of the GPS satellites received at the mobile terminal and said supplemental GPS data from said GPS station; and determining, at said GPS station, said global position of the mobile terminal from said precision GPS signal.

3. A method according to Claim 1, wherein step (a) comprises the steps of: receiving, at said mobile terminal, the signals from said plurality of GPS satellites and producing therefrom a precision GPS signal; and determining, at said mobile terminal, said global position of the mobile terminal from said precision GPS signal.

4. A method according to Claim 2 or Claim 3, further comprising the steps of: successively receiving, at said GPS station, a plurality of said precision GPS signal from said mobile terminal during a predetermined time interval and determining therefrom initial and subsequent global positions of said mobile terminal; determining a moving speed of said mobile terminal from said initial and subsequent global positions of the mobile terminal; and generating, according to said global positions, a map of an area of normal size when the determined moving speed is lower than a predetermined value and a map of an area larger than the normal size when the determined moving speed is higher than said predetermined value.

5. A mobile communication system comprising: a communications network; a mobile terminal for receiving GPS (global positioning system) signals from GPS satellites and transmitting the received GPS signals to said communications network; a server for receiving GPS signals from said GPS satellites and connected to the network for receiving the GPS signals from said mobile terminal to estimate a global position of said mobile terminal, and arranged to: (i) determine a number of GPS satellites whose transmissions are higher than a predetermined signal-to-noise ratio; (ii) determine a degree of precision of the estimated global position of said mobile terminal; (iii) determine the size of an area to be displayed on said mobile terminal according to said degree oLprecision; (iv) generate a map of said area of said determined size according to said global position of said mobile terminal; and (v) communicate the generated map to said mobile terminal via said communications network.

6. A mobile communicator system according to Claim 5, wherein said server is arranged to successively receive a plurality of said precision GPS signal from said mobile terminal during a predetermined time interval and is arranged to determine therefrom initial and subsequent global positions of said mobile terminal, and a moving speed of said mobile terminal from said initial and subsequent global positions of the mobile terminal, and is arranged to generate, according to said global positions, a map of an area of normal size when the determined moving speed is lower than a predetermined value and a map of an area larger than the normal size when the determined moving speed is higher than said predetermined value.

7. A mobile communication system comprising: a communications network; a mobile terminal for receiving GPS (global positioning system) signals from GPS satellites, and arranged to: (i) estimate a global position of the mobile terminal from the received GPS signals; (ii) determine a number of GPS satellites whose transmissions are higher than a predetermined signal-to-noise ratio; (iii) determine a degree of precision of the estimated global position from the determined number of GPS satellites; and (iv) determine a size of an area to be displayed on said mobile terminal according to said determined degree of precision; and a server for receiving from said mobile terminal information of said global position and said size via said communications network, and for generating a map of said area of said determined size according to the received information and communicating the map to said mobile terminal via said network.

. A method of displaying a map an a mobile terming comprg B - a) esUmadug a global pwidon of said mobile formic from signal transmitted from a plurality of GPS Global poaldaning By8b=) sabllibe and recked - b) den a degree oúprcnof Me emoted gkbal Id c) den a Dee of an area to be deplaned chord to said degree aúprecls d) generating Imp of said of said debit size dblg to said global podium of mobile to and e) displaying said map on said mobile termlual.

9. The method of Claim 8, wherein step (a) comprises the steps of: remove at mid mobile al, Swab transmitted hom said GPS IBM; À receiving, at a GPS system, Be Regale trantbd ham "d (;PS oa - {bee, pacing ouppenbl GPS data "d miming supp]emenbl GPS dam to We mobile Hi, producing at said mobile termless, a preddon GPS HI by Hug Be dpab of Me GPS eatelb received at We mobile to ant said supplemental GPS date from "d GPS en, and Jemh at said GPS - tem, Bad global poddon of Be mobile d donGPSd#.

10. The method of Claim 8, wherein step (a) comprises the steps of: receiving,, at said moWe termin.at signals 50m "id plurality oiGPS satellites and producing therefrom a precision GPS 41; and der at said mobile terminal global pot of Me teminaL 11. The method of Claim 8, 9 or 10, wherein step (b) comprises the steps of: delern atory poddans of Ihof aide GPS sate).libes from add pleebbn GPS signal are dote - .,h Tom Id atlaty potbns number oteql2ally divided arms of canter why mid line of GPS satellites cadet; and dein8 mid dry of precision of We emabd Cobb position *om Me denumb oúsaId divided my.

12. The method of Claim 8, 9 or 10, wherein step (b) comprises the steps of: den nut MOPS atellite'wle Hans are --: - firm the determined numb. oúGPS eallite 13. The method of Claim 8, 9 or 10, wherein step (b) comprises the steps of: den corteDat podhono of linof-dht GPS Platte from Id pi CAPS and dig add CQnS.Dty p - nut of equity divided areas of cons--in whim said 1ú-- GPSa - den a number of GPS Patentee whose bans are hider clan a predenet signal to noise ratio; ant defining degree of prey once GPS signal from B combinaban of Me den number of saw divided are" and We dermis ed number of GPS-11118.

14. The method of any one or more of Claims 8 to 13, further comprising the steps of: stlaovely xecdvin& at said GPS stat a phlralibr of asid preddon GPS signal from mobile tell during a pedened time intend and do dim initial and 06equt gkbal portions of said ddnmbdag a moving Speed of said mobile teemlaal from "d inlt{1 and subsequent global posits of we mobile terminal; and generating, rdh4; to said 1obal portions, a map of an of nonnal else When the diet mooring speed lower Wan a pi value and a map of Andrea 1err than enarmal adze wow We demhl moving Speed is higher *I add predeiennined A mobile communicadan System a=p a mmmuricatbasrk a server to Me network for Dunn a global postman from re-Red GPS Cal posits system) sisals; and a mobile terms Be receiving GPS dials from GPS satdll" and transmits the Coved G;PS Signals mid asnre Station via Said commundcadone nehrork to to came said Server Nation to estimate We global position of the mobile to eald Server n a degree of peon of the estimated Poseidon d said mobile terminal and deter Me size of an area be displayed on Id mobile terminal according to said degree of pi generating a map of said area of said determined size according to said global position of said mobile termdne1 ant communicating *'e generated map to said mobile terminal 16. The mobile communicaffan Brim of Claim 15 wherein said server den aonstelLetoy posits of lofsitht GPS satellites *om said Preston GPS signal and debrndnes from Id constellakry posidans a number of equally dinded are" of ellsBan in whim said lineofdt GPS satellites emit, and deeming said die of pry of Me espy global position *am the teternned number of said divided arma 17. The mobile commotion system of Claim 15 wherein said server "ernus a number of GPSateUites whose hW are hip - than a predeennined Ill-Ànolee ratio, and Jet said degree of Prussian of We estimated global potion fram the tide number of GPS satellites.

1 8. The mobile commun.ka system of Claim 15 wherein said server determines conebellatoy Hom of linefitht GPS satellites from said Preston Gin Signal, determines from said constellatory posl a number of equally divided any of aonstellaNan in which add lay sight GPS Battf em defies a nutria of GAS Ha - - whose Hans are hider Wan a prude dgul togae redo, and denims Id degree of pbbn of Me estimated global portion fiat a combination of Me determined number of said divided areas and We d =ned number of said GPS eatellitea 19- The mobile communication system of Claim 15, 16, 17 or 18, wherein said server successively rives a plurality of said preddon GPS gig nal from said mobile Seminal dig a predetermined time interval and der" Fiefdom elitist and subsequent global posld of said mobile terminal den - a moving speed of said mobile terminal from said iniffd subsequent globes posidons of Me mobile terminal ant Ma-, according to "d global portico, a map of am area of normal due wow We tend moving Wed is 1 Wan a predeb value and a map of an urea larger than Me nominal size when Me determined moving e hider Man Ed predetermined value.

2 Q. Mobile commun=ffcm system comprleing a conlmurdcadons networi;; a mobile terminal for receiving GPS (global podffonhg system) dgnale from GPS said, affng a global potion of We mobile teal from We received GPS signal, deeming a degree of pi of We estimated global position and deminhg We size of an area to be displayed on avid mobile tell according to salt degree of predsn; ant a server for receiving hom Id mobile terminal infonnadan of "d global poeldcm and said size vie said network, generating a Drip of said area of said deponed size awards to the received infomaNon and commurucadng We map to said mobile tonal via said network.

21. The mobile communicator Item of Claim 20, wherein said mobile textural determine constellatoypositios lof-sight GPS satellite from said precision GPS signal end Delano 10 Baid constellatory positions a number of equally derided areas of constellation whim said line of--t GPS salli exist, and determines said degree of premim of Me estimated global position from We dendned number Of add divided are - . 2 2. The moldy ammunicaon system of Claim 20; wherein said mobile terminal determines a number of GPS satellites wee t_ are hip pan a prude dgnakto noise ratio, and dekmlDes "d degree of precision of me ee,dmated global podHon from the deter number of GPS satellites.

2 3 Me mobile calm Of Claim 20, wherein said mobile seminal debminconstellatopositians of line-ofhtGPt; eateBiks from Bait pedebr GPS signal, tetenneo from said contatory positions a number of equally divided aresa conddlladan in whim said line-of-ht GPS eabllitea emit, determent a number of GPS satellite whose kmis are hider In a predemh Inane ratio, and delimit said degree of pumice of die estimated global poldon from a combination of We de.inai number of said divided Is ant Me determined number of "d GPS ttebe.