Huong dan su dung phan mem Gpsurvey 2.35

cC BN B TNG THAM MU pHNG TRC A - A hnh-

Hng dn s dng

Phn mm GPSURVEY 2.35(Static prosessing) (Dng cho loi my GPS Geoexplorer 3)

h NI 2-2004

Ni dung

trang 3

I I.1 I.2 I.3 I.4 II II.1 II.2 II.3 III III.1 III.2 IV V

Ci t phn mm Ci t Manager . . Ci t Trimnet . . Ci t Wave . . . Nhy p. . . . .

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3 3 3 3 3 3 4 4 11 11 22 27 28

tnh khi lc cnh o gps Chuyn File s liu thnh dng RINEX . . . . . . . . . . . . . . . Khi ng phn mm . . . . . . . . . . . . . . . . . . . . . . Cu trc hp thoi . . . . . . . . . . . . . . . . . . . . . . . Bnh sai li GPS . . . . . . . . . . . . . . . . . . . . . . . Bnh sai mt phng li GPS . . . . . . . . . . . . . . . . . . . S dng m hnh geoid OSU91a v GEM-96 bnh sai li cao GPS . . Bin tp kt qu . . . . . . . . . . . . . . . . . . . . . . . Phn ph lc . . . . . . . . . . . . . . . . . . . . . . . .

http://www.ebook.edu.vn

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I. Ci t phn mm M th mc cha phn mm GPSurvey2.35, xut hin 5 th mc con: Manager, Trimnet, Wave, GPSurvey2.35 v BTKQ_GPS. Ci t 4 th mc con sau (Hnh 1): 1.1. Ci t Manager - Nhy p Manager, - Nhy p Install 1.2. Ci t Trimnet - Nhy p Trimnet - Nhy p Install - Chn tt c cc Geoid Models, Hnh 1 1.3. Ci t Wave Thao tc tng t nh khi ci t Manager 1.4. Nhy p Th mc con BTKQ_GPS dng bin tp kt qu bnh sai li GPS. II. tnh khi lc cnh o gps II.1. Chuyn File s liu thnh dng RINEX S liu o c c lu gi di nhiu dng, ph thuc vo loi my GPS s dng. c th cp nht c vo cc phn mm khc nhau, phi chuyn chng vo dng chun: RINEX. i vi d liu o bng my Geoexplorer 3, dng phn mm GPS Pathfinder chuyn (Data Convert). Khi ng GPS Pathfinder, vo ca s Utilities \ Other \ SSF To RENEX (bng 1), s nhn c bng 2. Trong bng 2, s dng Browse (ca s Selected Files) gi File cn chuyn, Browse (ca s Output Folder) lu file chuyn. Nhn Enter () s xut hin bng 3.

Bng 1

Bng 2

D liu phi a vo bng 3 nh sau: - Antenna maker (im t my): + Name: Tn im; + Number: S hiu im; - Name (a ch): + Observer: Tn ngi o; + Agency: Tn c quan; - Receivers (Loi my thu):

Bng 3


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- Type: Loi; + Number: S hiu; + Version: Phin bn; - Antenna Position: V tr anten: + Height of bottom surface of Antenna above Maker ( cao anten t tm mc n vnh ca anten. + Eccentricity of Antenna center relative to Maker to the East ( lch t tm mc n vnh pha ng vnh anten). + Eccentricity of Antenna center relative to Maker to the North ( lch t tm mc n vnh pha Bc vnh anten). thun tin cho vic tnh ton sau ny, nn a s hiu im trm o vo cc v tr Name, Number, Observer v Agency. V d: + Name: 199 (199 l s hiu im t my); + Number: 199; + Observer: 199; + Agency: 199; + Type: 42; + Number: 1; + Version: 1; + Height of bottom surface of Antenna above Maker: 1.45 m (1.45 l cao thng ng t tm mc n tm anten, c th tnh theo nh l Pitagor). + Eccentricity of Antenna center relative to Maker to the East: 0.0 + Eccentricity of Antenna center relative to Maker to the North: 0.0 Xong nhn OK kt thc qu trnh chuyn i. Lu : Mi ln ch chuyn 1 File, chuyn File tip theo, qu trnh trn c lp li. II.2. Khi ng phn mm T mn hnh Window, vo Start \ Programs \ GPSurvey \ GPSurvey 2.35, hoc nhy p vo trn mn hnh chnh ca Window, s xut hin hp thoi nh bng 4. II.3. Cu trc hp thoi Ti liu ny ch trnh by nhng kin thc lin quan n tnh khi lc cnh v bnh sai li GPS. tm hiu thm v cc chc nng khc, c th tham kho trong cc ti liu hoc trc tip trong ca s Help ca GPSurvey 2.35. a. Utilities (Bng 5) a.1. System Check: Lit k tt c cc Files c trong phn mm GPSurvey c ci t. Bng 5 a.2. Set System Defaults Khi chn Set System Defaults, trn mn hnh s xut hin hp thoi (bng 6):

Bng 4


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- Project Root Directory: Th mc gc ca d n (ni ci t phn mm GPSurvey 2.35); - Antenna Type: Loi anten. Trng hp dng loi anten khng xc nh th chn Unknown External (bng 6).

Bng 6

Lu : Khi chn loi anten Unknown External, chiu cao ca anten phi c tnh v phng thng ng bng cch dng nh l Pitagor. - Antenna Meas. Methot: Phng php o anten gm: + Measured to bottom of antenna mount (o n y ca vnh anten); + True Vertical (Chiu cao thng ng). - Antenna Group: Nhm anten. Chn RINEX; - Riceiver Type: Loi my thu. Chn Geo Explorer; - Time Zone: VietNam (Khu vc tnh thi gian); - GMT Time Difference: lch thi gian a phng so vi gi quc t (7 gi). Cc ca s Add Time Zone, Delete Time Zone cho php thm hoc xo mt khu vc tnh thi gian. Khi chn xong nhn OK. S dng Menu Utilities, khi to cc Project (d n) mi, cc thng s ci t s c lu li. Nu ch dng mt loi my GPS thu d liu, ta khng cn chn li na. Cc thng s chn cng c th c a vo trong ca s Option ca New Project trong menu Project. a.3. Antenna Editor (Bng 7) Ca s ny cho php np cc thng s v anten. - Group: Nhm anten. Chn loi anten s dng thu tn hiu, v d: Compact Dome. Khi chn xong, cc thng tin v nhm anten xut hin na bn phi ca s Antenna Editor phc v cho vic kim tra.

Bng 7

- Uncorrected measurement methods: Phng php o chiu cao anten, cha c hiu chnh v chiu cao thng ng (Default RINEX Measured to Bottom of Antenna Mount). tnh cao thng ng vo ca s: - Calculate (bng 8): + Uncorrected: a gi tr chiu cao anten cha hiu chnh; + Nhp chut vo True vertical s nhn c chiu cao thng ng.

Bng 8

+ Units: n v o. Thng thng l mt (m). - New Group: a nhm anten mi; - Close: ng ca s. Menu Antenna Editor dng tnh chiu cao thng ng ca anten khi bit loi anten thu tn hiu. Trng hp chn loi anten Unknown External th khng cn phi vo menu ny.


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b. Project (Bng 9) b.1. New: Khi cn to mt Project mi, vo ca s Project New. Trn mn hnh s xut hin bng 9. Cc thng s phi a vo: Project: Tn d n, v d: HANOI (nn t tn d n vi nhiu nht 7 k t). Supervisor: Tn ngi lp d n (ngi gim st).

Bng 9

Noter - Ghi ch Nu chn Options, nhng thng s c ci t trong Utilities \ Set System Default vn c lu gi v khng cn t li (tr khi thay i loi my thu d liu). b.2. Open: M mt Project (d n) c; b.3. Modify: Sa mt Project; b.4. Close: ng Project; b.5. Delete: Xa mt Project; b.6. Status: Tnh trng ca Project; b.7. Exit: Ra khi Project;

Sau khi to xong mt Project, trong th mc C \ GPSURVEY \ PROJECTS s c th mc con mang tn d n va to (v d HANOI). Trong th mc con ny cn c nhiu th mc c to ra trong qu trnh to Project, nhng cn quan tm n cc th mc sau: C \ GPSURVEY \ PROJECTS \ GEOIDNET : Th mc cha kt qu tnh d thng trng lc cho mt elippsoid xc nh theo mt m hnh trng lc xc nh; C \ GPSURVEY \ PROJECTS \ NETADJ : Th mc cha kt qu bnh sai li GPS; C \ GPSURVEY \ PROJECTS \ TRIMVEC : Th mc cha cc file tnh cnh *.ssf hoc *.sst. c. Load (c d liu) Vo Menu Load, chn tip From RINEX File (bng 10), s nhn c bng 11:

Bng 10

Bng 11

- Chn Config, nhn c bng 12: Bng 12 c 2 ngn: - Ngn trn: Mode of Operation gm 4 la chn: + Batch Defer: c theo khi. La chn ny Load rt lu; + Batch Prompt: c nhanh. La chn ny Load d liu rt nhanh nhng khng kim tra c cc thng tin v trm o;

Bng 12

+ Interactive: Tng tc. La chn ny Load d liu nhanh, ng thi cho php xem v sa i cc thng tin v trm o. + Quick Edit / Batch Prompt: c nhanh, ging nh Batch Prompt. Nn chn Interactive.


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- Ngn di - Cc thng tin v trm o. Dng Mouse nh du ( ) v cc trng . Khi xong nhn OK. Quay tr li mn hnh bng 11. + Directories : Chn th mc cha File RINEX; + Drives: Chn a cha File RINEX; + List Files of Type: Chn RINEX Files (.obs). Cc Files RINEX c trong th mc c chn s xut hin ngn Files Found (bng 13). C th chn tng file, mt nhm flies hoc chn tt c cc file. + Chn tng File: Dng Mouse nh du file cn chn, sau chn Add . + Chn Mt nhm Files: Gi phm Ctrl ng thi dng Mouse nh du cc Files cn chn, sau chn Add . + Chn tt c cc Files: Chn Add All. Cc files c chn s c chuyn sang ngn Files Selected. Nu chn nhm File no, th nh du file trong ngn Files Selected, sau chn Remove. Nu mun b tt c cc files trong Files Selected , chn Remove All. Khi chn xong n Load Data. Xut hin mn hnh bng 14.

Bng 13

Bng 14

Trong bng 14 khng nh li File *.obs chn tng ng vi File *.nav. Nu File *.nav t ni khc, hoc c thay i g, phi chn li File *.nav tng ng. Xong chn OK. Lc ny bt u qu trnh Load d liu nh bng 15. Khi Load xong, xut hin bng 16.

Bng 15

Bng 16

Nhn OK, nhn c bng 17. Trong bng 17, cc thng s trong cc ca s c t khi to lp Project. Ch cn ca s Receiver Type, chn Geo Explorer. Nhn OK s nhn c bng 18: + Name: a S hiu im; + Long Name: a S hiu im ca Name; + ID: a S hiu im ca Name.

Bng 17

Bng 18


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Khi chuyn i File sang dng RINEX, nu Name, Number, Observer, Agency chn cng mt tn l S hiu im th trong bng 18 s hin ng tn l s hiu im (tn trm o) v khng cn phi a thm g vo bng ny. Nhn OK s nhn c bng 19: - Occupation Time (Local): Thi gian thu tn hiu ca mt Session: + Start: Thi gian bt u; Bng 19 + Stop: Thi gian kt thc. y thi gian hin trong bng khng nn thay i. C th i sau trong qu trnh tnh khi lc cnh. - Antenna Information: Thng tin v anten: + Hight: cao Anten ( cao tnh v phng thng ng). + Type: Unknown External; + Method: Phng php o - True Vertical: Theo phng thng ng; + Group: Nhm - RINEX. Cc gi tr ny c lu gi khi lp Project, ch phi ch cao anten. Khi chuyn i sang dng RINEX, cao anten ch lu gi n cm (2 ch s sau du phy). Nhng khi tnh khi lc cnh, cao anten phi ly n mm. Xong nhn OK. Qu trnh ny c lp li cho n khi Load xong tt c cc file trong ngn Files Selected. d. Process (X l): Vo Process \ Baselines nhn c bng 20:

Bng 20

Bng 21

tnh khi lc cnh o GPS, phi chn t nht l 2 Files s liu. Nu tnh tt c cc cnh, chn Add all, Nu tnh mt hoc mt s cnh, gi phm Ctrl v dng Mouse chn cc files cha cnh cn tnh. Xong nhn Add. S liu ngn Files s c chuyn sang ngn Selected Files. Cn b trm o no th nh du tn file ca trm o bng Mouse v chn Remove. Nhn OK s bt u qu trnh chuyn ti d liu nh bng 21. d.1. Menu Baseline (bng 22) d1.1. File \ Load - Dng c d liu; d.1.2. Edit + Station Position Dng a ta khi tnh cho trm o. Ch s dng khi tnh khi lc cnh cho li GPS Cp 0 hoc hng I. + Occupation List (bng 23). Dng sa d liu: Tn trm o, thi gian bt u v kt thc tnh cnh v cao anten. Cn sa trm no th dng Mouse nh du vo trm , sau dng lnh Edit sa.

Bng 22

Bng 23


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d.1.3. Process (X l) + Setup. Chn Setup, nhn c bng 24: - Static Baseline Generation: All Baselines: Chn tnh tt c cc cnh c th c trong mt session; Independent Set: Chn cc cnh khng lin kt vi nhau; User defined: Cc cnh do ngi tnh chn. - Process Times: Khong thi gian bt u v kt thc tnh chung cho cc cnh. - Satellites: Nhng v tinh c nh du ( ) l v tinh c thu tn hiu trong Session o (bng 25). - Advanced Controls: iu khin ch nh (bng 26)

Bng 25

Bng 26

Xt cc lnh trong bng iu khin: General (Tng quan): Cho php t ngng gc cao (Elevation mask), s bc lp ti a trong qu trnh tnh cnh (Maximum iterations), thi gian ti a tn hiu b nhiu hoc b ngt (Maximum fixable cycle slip) l nhng thng s c th thay i nng cao chnh xc khi tnh cnh. Quality (Cht lng, bng 27): 1- Observation Editting (Chn tr o): + Edit multiplier (Chn tng) + Level of confidence (Chn theo lp ring). Bng 27 2- Ratio test (T s kim tra): + Ratio Cutoff (T s ngt) + Level of confidence (Chn theo lp ring). 3- Reference variance test (Kim tra quan h tng quan) + Level of confidence (Chn theo lp ring). Phng n 1- Bt buc phi chn. Cn phng n 2- v 3- c th chn mt trong hai hoc c hai. Trong 1- v 2- c th chn mt trong hai trng hp iu khin qu trnh tnh cnh. Tu thuc vo yu cu cht lng cnh tnh chn cc gi tr ny cho ph hp. Xong nhn OK. Quay li mn hnh bng 24. Nhn OK kt thc ci t cu hnh v quay v bng 22. Lu : cc thng s trong bng 26 ch ci t mt ln cho ton b Project. Chn Process \ Baselines. Qu trnh tnh cnh bt u (bng 28).

Bng 28

Bng 29


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Khi tnh cnh xong, trn mn hnh xut hin thng bo: Processing Completed (bng 30). Chn OK kt thc.

d.2. Xem kt quChn Options \ Detailed Output (bng 29). Nhn c bng 31: La chn kt qu cn xem bng cch nh du ( ) vo trc cc - Summary: Tm tt kt qu (ph lc 1); - Phase ambiguities: Tr nhp nhng ca pha phch sng mang; - Processor controls: Kim tra qu trnh s l (ph lc 2);

Bng 30

Bng 31

- Station Tracking summary: Tm lc thng tin trm o (ph lc 3). Thng thng ch chn menu ny nh gi cht lng thu tn hiu tng cc v tinh v quyt nh xem nn loi b v tinh no v khong thi gian tt nht tnh cho mt session; - Combined tracking summary: Tm lc thng tin lin kt trm o (ph lc 4); - Continuous kinematic quality: Cht lng x l ng; - Residuals: Phn tha (Ph lc 5) Cn c vo ch tiu nh gi cht lng cnh o (bng 32) xem xt cnh tnh t hay cha. Nu cnh cha t th phi chn s v tinh phi loi khi qu trnh tnh ton, thi gian tnh ph hp v ngng gc cao v tinh X l cnh bng cch chn v tinh, thi gian tnh ph hp hon ton ph thuc vo kinh nghim ca ngi tnh. Nu tnh ton cn thn ri m vn khng t th phi o li. C th t Setup Reference Variance 30.Ch tiu nh gi cht lng cnh GPS

Bng 32Reference Variance 0.95 0.95 0.95 0.95

Chiu di cnh 10 km 10 20 km 20 30 km > 30 km

SolutionL1 fixed L1 fixed L1 fixed L1 fload

Rms 0.02+(0.004xS) 0.03+(0.003xS) 0.04+(0.002xS) 0.04+0.001xS)

Ratio 3.0 3.0 3.0 2.8

Khi cc ch tiu cnh GPS t, chn: File \ Save ghi kt qu tnh ton (bng 33). Kt qu tnh cnh c lu trong th mc: C \ GPSURVEY \ PROJECTS \ TRIMVEC.Bng 33

Trong mt Project, c th tnh ring tng cnh, chung cho 1 session, hoc chung cho c cng trnh. Cng c th to cc Project ring cho tng session hoc tng khu vc ca mt cng trnh. e. View Chn View \ Network Map (bng 34) s nhn c bng 35. Bng 35 cha nhiu menu con nhm phc v cho vic tham kho cc thng tin v cnh o. y ch nu cch tnh khp hnh bng Closure, cc chc nng khc bn c t tm hiu.


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Bng 34 Bng 35

Khi chn Baselines \ Closure, trn mn hnh xut hin s tnh cnh v hai bng con: Baseline v Closure. Di chut trn cnh no ca s tnh th cnh i sang mu . Nhp chut phi ln cnh mu , cnh i sang mu xanh l cy, ng thi trn bng Baseline xut hin cc thng tin v cnh c chn gm: Cnh o t s hiu n s hiu, chiu di cnh, phng v, chnh cao, Ratio, Variance Mun bit thm thng tin nhp chut vo More cui mn hnh. Trn bng Closure c cc sai s v ta , tng chiu di cc cnh c chn v tng sai s (bng 36). Nu cc cnh c chn to thnh tam gic (hoc a gic) khp kn th tng sai s tr thnh sai s khp hnh. - Nn chn tng sai s < 5 ppm (tng ng 1/200.000); - Cc cnh c o 2 ln th cn c vo kt qu khp hnh chn gi tr chnh xc nht.Bng 36

Cc hnh khp c sai s t ch tiu, c nh cc sai s ny li bng cch nhp chut vo Lock Validate Update. khp mt hnh mi, nhp chut vo Reset v qu trnh tnh khp hnh c lp li. ghi kt qu khp hnh chn File \ Save Closure Log. III. bnh sai li GPS Sau khi tnh khi lc cnh xong, tin hnh bnh sai li GPS bng phn mm GPSurvey. Bnh sai li GPS bng Geomatic Offic cng rt thun tin v quy trnh khng khc so vi bnh sai bng GPSurvey 2.35. Tuy nhin kt qu ca bnh sai bng Geomatic Offic c vit di dng Web nn rt kh khn bin tp thnh qu. Trong khi cha c chng trnh bin tp kt qu ca Geomatic Offic, Phng Trc a - a hnh son tho hng dn bnh sai bng GPSurvey 2.35. III.1. Bnh sai mt phng li GPS Nu tt c cc cnh c tnh trong mt Project th kt qu tnh cnh c lu trong th mc C \ GPSURVEY \ PROJECTS \ TRIMVEC. Cn tnh cnh trong cc Project khc nhau th Load (c) d liu vo th mc ny bng cch: Vo Load \ From SSF Solution File (bng 37), s nhn c (bng 38):

Bng 37

Bng 38

Trc khi chn cc cnh xy dng li, nhp chut vo ca s Config, nhn oc (bng 39): Mode of Operation (Phng php ngi x l chn):


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- Batch Defer: X l ton li mt cch chm ri, chc chn; - Batch Prompt: X l ton li ngay lp tc; - Interactive: X l ton li c tc ng ln nhau; - Quick Edit / Batch Prompt: Ging nh Batch Prompt.

Bng 39

Cch tt nht nn chn phng php Interactive. Station ID - Tn trm t my: - Strip underscores from Station ID - B qua cc trm my m tn im c gch di; - Strip leading zeros from Stations ID - B qua cc trm my m khng c tn im; - Use Station ID is name if missing - S dng cc im m tn trm my t sai. Khi tnh ton bnh sai cn t du () vo cc trng hp ca Station ID. Station Name - Tn trm my: nh du nhc () vo Create Station Name if it Not does Exist - t tn im trm my nu cha c. Sau khi t Config thch hp, vo th mc Trimvec Load d liu (Bng 40): C th Load tng cnh (file) hoc mt s cnh, bng cch nhn Shipt + bm chut vo cc cnh cn chn, sau nhp chut vo ca s Add. Nu chn tt c cc cnh th nhp chut vo ca s Add All. Nu mun b cnh no th nh du vo cnh v s dng ca s Remove chuyn tr li.

Bng 40

Kt thc vic chuyn d liu nhn Load Data hoc OK. Trn mn hnh xut hin ca s cho tng cnh (bng 41): Nu ng chn Interactive th nhn OK, cn chn cc ch khc th thay i du () trc Batch Defer hay Batch Prompt, sau nhn OK. Mn hnh xut hin (bng 42):

Bng 41

y cho php ta kim tra li cc ch tiu v cnh cng nh li gii tt nht c chn. - Station Information: S hiu im hai u cnh. C th thay i tn im bng cch vo ca s Edit. - Baseline Information: Nu mun xem thm thng tin th vo ca s More, cn mun chn li gii khc - vo Solution Type. Khi kim tra xong tt c cc thng s v cnh th nhn OK. Qu trnh ny tip tc cho n khi Load xong tt c cc cnh. Cch tt nht l cho chng trnh t chn li gii cho cc cnh.

Bng 42


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Khi load xong d liu Vo Adujst \ Network s nhn c bng 43: y l cc Modules cho php bnh sai mt li GPS. Ln lt xt cc Modules ny theo tin trnh bnh sai li GPS. Nhy p chut vo s nhn c bng lnh ca GPS Network Module (bng 44)Bng 43

MAIN MENU

GPS NETWORK MODULEBuild Network from Trimvec Directory View Contents of Trimvec Directory View Vectors Summarize Network Edit Network Network Adjstmemt Save GPS Network to Disk View Map of GPS Vectors View Trimvec File

STATUS Network HANOI Datum UNKNOWN 0 Solutions 0 Baselines 0 Unique Vector 0 Stations Printer OFF Plotter OFF

ESC = EXIT = MOVE Enter = SELECT F1 = HELP

Bng 44

Dng phm mi tn ln hoc xung a vch sng vo vo ca s cn chn, sau n Enter (). Ln lt xt tng ca s trong bng 44: + Build Network from Trimvec Directory: Khi vo Build Network from Trimvec Directory nhn c hnh o ni vi tt c cc cnh c chn a vo bnh sai. n ESC quay v ca s mn hnh nh bng 44. Khi bng 44 c dng nh bng 45.MAIN MENU GPS NETWORK MODULEBuild Network from Trimvec Directory View Contents of Trimvec Directory View Vectors Summarize Network Edit Network Network Adjstmemt Save GPS Network to Disk View Map of GPS Vectors View Trimvec FileESC = EXIT = MOVE Enter = SELECT

STATUS Network HANOI Datum WGS-84 5 Solutions 5 Baselines 5 Unique Vector 4 Stations Printer OFF Plotter OFF

Bng 45

F1 = HELP

S khc bit duy nht y l phn mn hnh con STATUS. Khi li c xc nh vi Datum: WGS-84, s gii php tnh cnh, s cnh, s lng vector v s trm my. + View Contents of Trimvec Directory: xem cc files cha vector cnh; + View Vectors: Dng kim tra cc gii php tnh cnh cng nh cht lng ca cc cnh c tnh. Khi vo View Vectors s nhn c bng 46:


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Bng 46

C th chn xem mt, mt nhm gii php vector hay tt c cc vectors c trong li bng cch chn t Solutions # m n Solutions # n, vi m n v m,n nguyn dng. Mi mt gii php cnh cho ta mt bng cha cc tham s vector c chn nh bng 47:

GPS NETWORK MODULEChoose Trimvec Solutions to view 1 View from Solutions # 5 to Solutions # = MOVE ESC = EXIT Enter = SELECT F1 = HELP

Trimvec File 00000196.WAV Session 345c Solution # 1 From Station GPS1 to Station N00 latitude N 21 03' 17.026740" longitude E 105 53' 18.447820" height -16.9833m normal azimuth= ellipsoid distance= delta height=ESC = EXIT

Version W 2.35 Vector # 1 of 1 single baseline WGS-84 Time Dec 11 02:35:00 2003 N 21 02' 00.659187" =0.0005m E 105 53' 55.733570" =0.0005m -18.1622m =0.0037m = 0.0405" = 0.0005m = 0.0037mF1 = HELP

155 22' 25.262678" 2583.635765m -1.1788m = SCROOL

Ratio=9.3 Reject %= 1

Bng 47

+ Summarize Network: a vch sng v Summarize Network v nhn (),c bng 48:SUMMARY VIEWS OF GPS VECTORSSession Names -- short list Session Names -- long list Station Names -- short list Station Names -- long list Apparently Duplicated Stations Redundant Vectors Global Network Closures Duplicated Trimvec Files Not Read Defective Trimvec Files Not ReadESC=EXIT =MOVE Enter=SELECT F1=HELP

GPS NETWORK MODULESTATUS Network HANOI Datum WGS-84 5 Solutions 5 Baselines 5 Unique Vector 4 Stations Printer OFF Plotter OFF

Bng 48

Trong bng 48: - Session Names -- short list: Xem Session Names vi tn rt gn, v d 354c - 354 l ngy Julian, c l ln o th 3 theo vn abc. - Session Names -- long list: Xem Session Names vi tn y , gm Session Names, s gii php (Solution), tn files cha Vector GPS v im u v im cui ca mi Vector; - Station Names -- short list: Xem tn cc trm o; - Station Names -- long list: Xem Station Names vi tn y , gm Station Names, s gii php, o t im () n im (), thuc Session () v tn files cha cc Vector GPS ny; - Apparently Duplicated Stations: Xem cc trm o c b trng tn hay khng? - Redundant Vectors: Xem c Vector tha khng?


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- Global Network Closures: Kim tra khp ton li GPS. Phn ny s trnh by trong phn bin tp kt qu bnh sai li GPS. - Duplicated Trimvec Files Not Read: Khng c (Load) cc files trng tn; - Defective Trimvec Files Not Read: Khng c (Load) cc files khng t cht lng. + Edit Network (bng 49):Bng 49

EDIT GPS VECTORS

GPS NETWORK MODULESTATUS Network HANOI Datum WGS-84 5 Solutions 5 Baselines 5 Unique Vector 4 Stations Printer OFF Plotter OFF

Delete Trimvec Solution Add Trimvec Solution FIX/FLT/TRP Substitution Change Session Names Change Station Names Edit Single Vector

ESC=EXIT =MOVE Enter=SELECT F1=HELP

- Delete Trimvec Solution: Xo mt hay nhiu Vector trong li bng cch chn t gii php # n gii php # (Bng 50). - Add Trimvec Solution: Thm mt hay nhiu gii php (cnh) , vi iu kin trong th mc C \ GPSURVEY \ PROJECTS \ TRIMVEC vn cn nhng cnh cha c c (LOAD) khi xy dng li GPS. - FIX/FLT/TRP Substitution: Cho php thay i tnh cht ca li gii ca tng Vector, v d t FIX FLT, t FIX TRP - Change Session Names: Cho php thay i tn ca tng Session; - Change Station Names: Cho php thay i tn ca tng Station; - Edit Single Vector: Cho php thay i tn ca tng Session, Station cng nh to u v cui ca mi Vector.Bng 50

EDIT GPS VECTORS

GPS NETWORK MODULE

+ Network Adjustment: Khi chn Network Adjustment xut hin bng 51, nhc bn c ghi li ton b kt qu tnh ton bnh sai li GPS hay khng? Tr li (Y) hoc (N) bng cch n phm Space.Bng 51

EXIT GPS NETWORK MODULEDO YOU WANT TO SAVE THE NETWORK TO DISK BEFORE EXIT? Y(ESC returns to Main Menu)


15

Sau nhn phm (), lp tc xut hin bng 52: Xt cc ca s ca bng 49 theo ng cc bc bnh sai li GPS:Bng 52

MAIN MENU

NETWORK ADJUSTMENT MODULEDisplays Adjustment Menu Change Coordinate System Datum Definition Computation Utilities Data Base Connection Save Network to Disk GPS Network Module Terrestrial Network ModuleNetwork STATUS Datum: WGS-84 System: Geographic Zone: Globals Linear Unit: Meter Computations: Computed 4 Stations 5 Observatiens 5 GPS 0 Terrestrials 0 Geoid Printer OFF Ploter OFF


- Datum Definition: Vo ca s Datum Definition xut hin bng 53:Bng 53

MAIN MENU

NETWORK ADJUSTMENT MODULE

Khi s dng GPSurvey 2.35a ln u, ta ch c cc Elippsoid c ci t sn xem c bao nhiu Elippsoid, bn chn View Known Datums, xa mt Elippsoid, chn Delete Datum, cn thm mt Elippsoid, chn Add New Datum (bng 54).Bng 54

DATUM NAMEWGS-84 WGS-72 NAD-83 NAD-27 nassau corva Krasov -

SEMI-MAJOR AXIS SEMI-MINOR AXIS6378137.0000 6378135.0000 6378137.0000 6378206.4000 6378137.0000 6378206.4000 6378245.0000 6356752.3100 6356750.5200 6356752.3100 6356583.8000 6356752.3140 6356583.8000 6356863.0188

1/f298.25722356300 298.26000000000 298.25722210100 294.97869820000 298.25722014343 294.97869821390 298.30000000000

F1 = HELP ENTER = ADD DATUM

EDIT KEYS

Ch cn thm tn, gi tr bn trc ln a v dt (phn mm t tnh bn trc nh b), hoc tn, bn trc ln v bn trc nh (phn mm t tnh gi tr 1/f) ca Elippsoid l ta ci t thm c mt Elippsoid vo phn mm bnh sai li GPS.


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S dng phn mm GPSuvey 2.35a t ln 2 tr i, khi cn mt Elippsoid c th, vo ca s Change Datum trong bng 53 v a vch sng vo Elippsoid cn chn, sau nhn - Change Coordinate System: Trong bng 52, chn Change Coordinate System s nhn c bng 55:Bng 55

CHOOSE COORDINATE SYSTEM NETWORK ADJUSTMENT MODULEGeographic User-defined Transverse Mercator User-defined Lambert User-defined Oblique Mercator Universal Transverse Mercator NAD-83 State Plane Coordinates NAD-27 State Plane Coordinates User-defined Projection LibraryExit

Ca s ny cho php chn cc h thng ta . Xt mt s h thng chuyn dng: + Geographic: H thng ta a l; + User-defined Transverse Mercator: H thng ta Transverse Mercator do ngi s dng nh ngha. Khi chn User-defined Transverse Mercator s nhn c bng 56: Cc tham s trong bng 56 c thay th cho ph hp vi h ta bn ang s dng. V d, trong h ta Gauss, kinh tuyn trc 105 00 00 sau khi a cc gi tr ny vo bng 56 s nhn c bng 57. Bng 56 Bng 57USER-DEFINED TRANSVERSE MERCATOR PROJECTION USER-DEFINED TRANSVERSE MERCATOR PROJECTION

Name of projection: HANOI Central meridian: E 10550'19.000000" Scale along central meridian: 0.999997169673 False northing for origin: 200000.0000 False easting for origin: 300000.0000ESC=EXIT =MOVE Enter=SELECT F1=HELP

Name of projection: HANOI Central meridian: E 10500'00" Scale along central meridian: 1.000000000000 False northing for origin: 0.0 False easting for origin: 500000.0000ESC=EXIT =MOVE Enter=SELECT F1=HELP

- Adjustment Menu: Trong bng 52, chn Adjustment Menu, nhn c bng 58:Bng 58

MAIN MENU



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Xt cc trng hp ca bng 58: + Coordinate Fix Status: Dng FIX ta , cao cc im gc: - Trong h ta Geographic (bng 59):Bng 59

COORDINATE EDITING FIELDPT# NAME LATITUDE / LONGITUDE ELL(H)/ORTH(h) FIX NWN

GPS1

N 2103'17.026740" E 10553'18.447820"

-16.9833 0.0000 -18.1622 0.0000 -20.4659 0.0000 -16.4174 0.0000

----

YXH-

N00

N 2102'00.659187" E 10553'55.733570"

YXH-

TG41

N 2057'51.863245" E 10547'43.035732"

YXH-

TG51

N 2104'54.690554" E 10546'42.963767"

YXH-

ESC=EXIT ENTER=SAVE TAB=CURSOR PgUp PgDn (ALT) F2-F5=(SET) CLEAR FIX

Gi th c im gc ta TG51, TG41 v v gc cao N00 vi gi tr ta , cao cho trong bng 60:Bng 60 Stt 1 2 3 SH B L X(m) Y(m) H(m) h(m) 5.143 6.868 Lo 105 --TG41 21 04' 54.690554" 105 46' 42.963767" TG51 21 04' 54.690554" 105 46' 42.963767" N00 2319397.145 582675.684 31.874 2332393.239 580876.851 33.947

Sau khi a cc gi tr ny vo bng 56, nhn c bng 61:Bng 61

COORDINATE EDITING FIELDPT# NAME LATITUDE / LONGITUDE ELL(H)/ORTH(h) N 2103'17.026740" E 10553'18.447820" 2 N00 N 2102'00.659187" E 10553'55.733570" 3 TG41 N 2057'52.339590" E 10547'41.872796" 4 TG51 N 2104'55.146187" E 10546'41.801617" -16.9833 0.0000 33.9470 0.0000 31.8740 0.0000 -16.4174 0.0000 XY YXHXYH YXHH YXHFIX --NWN YXH1 GPS1

ESC=EXIT ENTER=SAVE ,TAB=CURSOR PgUp PgDn (ALT)F2-F5=(SET)CLEAR FIX

+ Cng cc gi tr ta , cao ca bng 60, trong h ta User-defined Transverse Mercator, nhn c (bng 62):


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Bng 62

COORDINATE EDITING FIELDPT# NAME 1 GPS1 NORTH/EAST 2329435.1640 592343.9137 2 N00 2327092.2637 593433.7069 3 TG41 2319397.1450 582675.6840 4 TG51 2332393.2390 580876.8510 ELL(H)/ORTH(h) -16.9833 0.0000 33.9470 0.0000 31.8740 0.0000 -16.4174 0.0000 XY YXHXYH YXHH YXHFIX --KNWN YXH-

ESC=EXIT ENTER=SAVE ,TAB=CURSOR PgUp PgDn (ALT)F2-F5=(SET)CLEAR FIX

Nh vy, c th FIX ta , cao, hoc ch ta , hoc ch cao ca mt im. Sau khi a cc gi tr ta , cao ca cc im gc xong, nhn () ra khi bng 62. Tr li mn hnh bng 58, vo ca s Weighting Strategy (chn trng s), nhn c bng 63:Bng 63

MAIN MENU


Vo ca s GPS Observations, nhn c bng 64, chn tip Scalar, s c bng 65:Bng 64 WEIGHTING STRATEGY Scalar Summation Station WeightingESC=Exit WEIGHTING STRATEGY -- SCALING

Bng 65NETWORK ADJUSTMENT MODULE

Current strategy: all gps solutions Current value set: alternativeSOL # SCALAR SOL # SCALAR SOL # SCALAR

1 2 3 4 5

113.58 0.60 67.66 187.30 157.87F1 = HELP ENTER = A CCEPT VALUES PGUP/PGDN

Cc ch v cch la chn trong bng 65 gm (bng 66):Bng 66

Current strategy: all gps solutions Current value set Defaulteach gps solution var comp group Alternative User-Defined


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- Chn cho ton li c chung trng s vi 3 phng php: a. All GPS Solution (Chung cho ton li): Vi 3 cch chn trng s nh sau: + Default: Phn mm t chn trng s lun bng 1.0; + Alternative: Phn mm t chn trng s ty theo tnh cht ca tng li; + User-Defined: Trng s do ngi tnh ton chn. b. Each GPS Solution (Cho tng cnh trong li): + Default: Phn mm t chn trng s lun bng 1.0; + Alternative: Phn mm t chn trng s ty theo chiu di ca tng cnh trong li; + User-Defined: Trng s do ngi tnh ton chn. c. Var Comp Group: Phng php dng ma trn tng quan. Chn Default, Alternative, User-Defined ging nh mc b. Trng s ng mt vai tr rt quan trng trong vic bnh sai li trc a. La chn trng s ph hp s lm tng chnh xc ca li. i vi cc li yu cu chnh xc thp, c th s dng cc trng hp sau (bng 67):Bng 67

Current strategy: all gps solutions Current value set Defaulteach gps solution Alternative Bng 68

Hoc Current strategy: all gps solutions Current value set Defaulteach gps solution Alternative

i vi li yu cu chnh xc cao hn (t a chnh c s tr xung), bt buc phi chn nh trong bng 68.Bng 69

Current strategy: each gps solution Current value set alternative Khi tnh bnh sai li trc a tng ng hng II, hng I hoc li GPS cp 0 nh nc, trng s s c ngi tnh chn t c chnh xc ph hp vi yu cu ca cc cp hng li. La chn trng s ph hp cho tng cp hng li l mt vic kh v tn nhiu thi gian, cng sc. Quay v ca s ca bng 58. Chn Special Controls, c bng 70. Chn tip Global Adjustment Controls, nhn c bng 71.Bng 70

MAIN MENU



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Trong bng 71, cc thng s c ci t sn. y lu hai loi thng s sau:+ Compute horizontal adjustment: Y - Ch tnh bnh sai ta + Compute vertical adjustment: Y - Ch tnh bnh sai cao.

Tu thuc vo la chn (Y) hoc (N) c th ch tnh bnh sai ta , hoc ch tnh bnh sai cao hoc tnh bnh sai c ta v cao.Bng 71 GLOBAL ADJUSTMENT CONTROLS NETWORK ADJUSTMENT MODULE Y Y Y Y N N N Y Y N N N Y 1.0000 1.0000 10 1.0e-005 5.0e-003 Display adjustment screen graphics Write ellipse displays to disk files Write histogram display to disk file Display covariant terms Direct all adjustment text displays to printer Write plotter file for network map Write plotter file for ellipses Compute horizontal adjustment Compute vertical adjustment Use reduced column profile if possible Model all heights on ellipsoid (one-height mode) Restrict covariant terms display to observed lines 'Save to Disk?' prompt before exit Univariate sigma scalar: Bivariate sigma scalar: Maximum number of adjustment iterations: Tolerance on residuals to end iterations: Last-ditch tolerance on residuals :F1=HELP ENTER=ACCEPT VALUES ESC=EXIT

F5=SAVE NEW SYSTEM DEFAULTS

Sau quay v ca s ca bng 58 v chn Adjust Network () bnh sai li. Qu trnh bnh sai kt thc, chn ca s DISPLAY xem kt qu. Vo Display, vo tip Adjustment Results nhn c bng 72: - Observation Closures: Sai s cc tr o trong li gm: Sai s phng v, sai s chnh cao v sai s khong cch; - Statistical Summary: Ch tiu nh gi kt qu bnh sai. Network Reference Factor: Yu t quan h li. Nu kt qu bnh sai tt th gi tr ny phi bng 1.0 hoc 1.0;

Chi-Square Test ( = 95 %) = Pass. Nu kt qu bnh sai tt th gi tr ny phi =Bng 72

PASS.MAIN MENU NETWORK ADJUSTMENT MODULE


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Nu kt qu tnh cnh tt m cc gi tr ny cha t th tip tc qu trnh bnh sai (Adjust Network () cho n khi cc gi tr trn c tho mn. - Coordinate Adjustment: Ta , cao v sai s ca chng sau bnh sai - Observation Adjustment: Tr o, s hiu chnh, tr o sau bnh sai v cc sai sai s tng ng; - Largest Standardized Residuals: Tr o, s hiu chnh, tr o sau bnh sai v cc sai sai s tng ng;- Covariant Values: Phng v, sai s phng v; chnh cao, sai s chnh cao; cnh , sai s o cnh v sai s tng i o cnh. Khi kt qu bnh sai chp nhn c, quay v mn hnh bng 49, vo ca s Computation Utilities, vo tip ca s Long Format Point-Point Inverse s xut hin bng 73. Trong bng 73, thay cc gi tr t n ,(v d xem bng 74) xut pht t mt im (tt nht l t 1 im gc) nhn c bng tng hp thnh qu bnh sai bng tn file Scratch.fil trong th mc WINDOW \ TEMP v kt thc qu trnh tnh ton bnh sai.Bng 73

INVERSE TEMPLATEFROM TG41 N00 GPS1 TG51F1 = HELP

NETWORK ADJUSTMENT MODULETO GPS1 N00 TG41 TG51PGUP/PGDN

N N N N

N N N N

ENTER = ACCEPT VALUES

Bng 74

INVERSE TEMPLATEFROM GPS1 N00 TG41 TG51F1 = HELP

NETWORK ADJUSTMENT MODULETO GPS1 N00 TG41 TG51PGUP/PGDN

Y N N N

N Y Y Y

ENTER = ACCEPT VALUES

III.2. S dng m hnh geoid OSU91a v GEM-96 bnh sai li cao GPS S dng GPS o ni cao l mt vic hon ton c th nu chng ta xy dng c mt mng li trng lc v mt v t chnh xc cao. Tuy nhin, xy dng mng li trng lc l mt vic kh khn, gian kh v tn nhiu tin bc v thi gian. Trong khi cha lm c vic , chng ta hy tn dng nhng thnh qu ca th gii phc v cho mc ch ca mnh: S dng m hnh geoid OSU91a hay GEM-96 o ni gn ng cao bng GPS. M hnh geoid OSU91a: M hnh trng trng lc tri t OSU91a c thit lp trn c s s liu trng lc o mt t bng cc phng php khc nhau, kt hp vi s liu v tinh. S dng cng thc Stock vi chui iu ho cu c pht trin ti bc n=m=176 vi 63.886


22

h s. M hnh geoid OSU91a c kch thc 30 x 30 vi chnh xc cao Geoid ti nt li l 2.0 2.5 m. M hnh Geoid quc t GEM-96: Trn c s m hnh trng trng lc tri t OSU91a, b sung v chnh xc ha li d liu xy dng m hnh Geoid quc t GEM-96, vi chui iu ha cu c pht trin ti bc n=m=360 v 130.676 h s. M hnh Geoid quc t GEM-96 c kch thc li 15 x 15 vi chnh xc cao ti nt li 0.5 1.0m. Cn lu rng hin nay ch yu s dng m hnh GEM-96 tnh cao bng GPS, tuy nhin trong mt s trng hp v mt s khu vc m hnh geoid OSU91a li cho kt qu tt hn. y nu phng php s dng phn mm GPSurvey 2.35 tnh bnh sai cao. Vo ca s Network Adjustment Module (t bng 40), chn: - Datum: WGS-84; - Coordinate System: Geographic - Fix 1 im bt k (c ta X, Y v cao H) v vo ca s Adjust Network bnh sai li GPS. Lu : im cn chn FIX to , cao khng nht thit phi l im gc. To , cao FIX l cc gi tr c sn, c GPS xc nh. Nu im FIX trng vi im gc th cng khng a gi tr ta v cao chnh xc ca im vo tnh ton. Sau khi bnh sai xong, quay tr li mn hnh bng 52. Vo ca s Terrestrial Network Module, c bng 75:Bng 75

MAIN MENU


Tr li Y + , nhn c mn hnh nh bng 76. Ti bng 76, vo ca s Geoid Module, nhn c bng 77:Bng 76

MAIN MENU

TERRESTRIAL OBSERVATIONS MODULEObservations Station Coordinates Computation Utilities Datum Definition Coordinate System Network Maps Save Network to Disk Network Adjustment Module Geoid ModuleNetwork STATUS Name: HANOI Datum: WGS-84 System: Geographic Zone: Globals Linear Unit: Meter Computations: Unraduced 4 Stations 0 Observatiens Printer OFF Ploter OFF



23

Bng 77

MAIN MENU

GEOID MODULESTATUS Project:HANOI Number of Known Models: 4 Current Model ID Number: 4 Current Model:Geoid90 West System:Geographic 4 Stations Printer OFF Ploter OFF

Displays Estimate Geoid Heights Load Geoid Model Import New Geoid Model Delete Geoid Model Terrestrial Observations Module This geoid model does not cover project ExitESC=EXIT =MOVE Enter=SELECT F1=HELParea. Choose a new model.

Trong bng 77 chn Load Geoid Model (la chn m hnh Geoid), c bng 78:Bng 78

Chn WW15MGH (File cha d liu trng lc ca GEM-96), chng trnh s quay li mn hnh bng77 . Tip tc chn Estimate Geoid Heights (c lng cao Geoid), c bng 79, gm: - Create Display Grid: Hin th v tr im o GPS v to li Geoid cng cao ti cc mt li; - Create DCO File: To file cha cao Geoid ti cc im o GPS; - Create Network Point Listing: Tnh cao Geoid ti cc im o GPS; - Export Gridded Model: Xut d liu thnh File cha cao Geoid ti cc im o GPS. Nh vy cc bc phi thao tc y l:Bng 79

+ Vo ca s Create Display Grid, c s v tr im o GPS, Chn Enter (), c bng Grid Deffinition, chn Enter (), c bng Geoid Hights from WW15MGH ( cao Geoid ca GEM-96). + Vo ca s Create DCO File; + () + Vo ca s Create Network Point Listing + ();


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+ Vo ca s Export Gridded Model + (). Quay tr li mn hnh bng 77, chn Terrestrial Observations Module, quay v mn hnh bng 76. Tip tc chn Observations, c bng 80:Bng 80

OBSERVATIONS MENU

TERRESTRIAL OBSERVATIONS MODULEOBSERVATION STATUS 0 Angles 0 Directions 0 Azimuths 0 Distances 0 Vertical Angles 0 Delta Orthometric Heights 0 Delta Geoid Heights 0 Observed Geoid Heights

Data Entry View Observations Modify Observations Delete Observations Default Observation Parameters Terrestrial Observations Module Access DCO FilesEXIT

Trong bng 80, chn Default Observation Parameters, c bng 81:Bng 81

DEFAULT OBSERVATION PARAMETERSAbsolute

TERRESTRIAL OBSERVATION MODULEProportional (ppm) Reject limit

Minimum Standard Error

Agles 0.00 2.50 Directions 1.00 2.50 Azimuths 1.00 2.50 EDM Distances 0.0050 5.0000 0.0200 Microwave Distances 0.0100 10.0000 0.0500 Tape Distances 0.0010 10.0000 0.0300 Stadia Distances 0.3000 10 000.0000 1.0000 One-way vertical Agles 10.00 30.00 Reciprocal vertical Agles 5.00 20.00 Delta Elevations 0.0030 20.0000 0.0050 Delta Geoid Heights 0.1000 Observed Geoid Heights 1.0000 Current Linear Units: Meter (1.000000 / 1.000000) x Meter Compute Orthometric Height Corrections: no Compute Correlations For Geoid Model no Write Data Entry Log noF1 = Help Enter = Accept Values F5 = Save New System Defaults

Bng ny nu cc thng s li trng lc dng tnh cao GPS. Tnh cao GPS l mt vic rt kh, cn rt nhiu t hp kin thc: t thit k, o c n tnh ton v am hiu tng tn v m hnh trng lc c p dng Ti liu ny mi ch dng li mc hng dn s dng phn mm. lm vic ny trong bng 81, ch cn thay i nh sau (Bng 82):Bng 82 Compute Orthometric Height Corrections: Compute Correlations For Geoid Model Write Data Entry Log Yes Yes Yes


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Chn Enter quay v bng 80. Trong bng 80 chn tip Access DCO Files chp nhn cc thng s trng lc la chn v nhn c bng 83:Bng 83

OBSERVATIONS MENU

TERRESTRIAL OBSERVATIONS MODULE

Trong bng 83, chn Load Observations from File, sau dng lnh Exit quay v bng 80, chn tip Exit quay v bng 76. Trong bng 76, chn Computation Utilities nhn c bng 84:Bng 84

COMPUTATION UTILITIES

TERRESTRIAL OBSERVATIONS MODULECOMPUTATIONS STATUTS

Compute Network Display Observation Closures Display Coordinate Computations Clear Network Computations Disable/Enable Observations Point Inverses Pt-Pt Angles Recopute Single Point ExitESC=Exit = Move Enter=Select F1,F2=Help

Observations:4 Unreduced 0 Reduced

Known Coordinates:8 Horizontal 5 Vertical

Unknown Coordinates:0 Horizontal 3 Vertical

Fixed Coordinates:2 Horizontal 2 Vertical

Chn Compute Network + () v quay v bng 76. Trong bng 76, chn Save Network to Disk + (ESC), sau chn Network Adjustment Module s xut hin bng 85:Bng 85

MAIN MENU

TERRESTRIAL OBSERVATIONS MODULE

Tr li Y (dng phm Space) + () v quay v bng 45. Trong bng 45, chn Network Adjstmemt s xut hin bng 86 v la chn cc tham s ca bng 86 nh sau (bng 87):


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Bng 86

Bng 87

LOAD NETWORK ADJUSTMENT MODULECurent Adjustment Network: GPS Network: Terrestrial Network:F1=Help

LOAD NETWORK ADJUSTMENT MODULECurent Adjustment Network: GPS Network: Terrestrial Network:F1=Help

load Do not load Do not load

Do not load load load

ESC=Return to Control Module

ESC=Return to Control Module

S nhn c bng 52. Qu trnh bnh sai li ta , cao GPS s c tip tc t bng 52 n bng 74. S khc bit v gi tr ca mt s bng trong qu trnh bnh sai ln ny l do s tham gia ca m hnh trng lc s dng v cao ca cc im gc c FIX bng cao trc a. cao trc a ca im gc cao c tnh bng cng thc:

H = h + ,Trong : H - cao trc a ; h - cao thy chun;

- D thng trng lc (ly t File Network.txt thuc th mc C \ GPSURVEY \ PROJECTS \ GEOIDNET \GMOD vi s hiu im tng ng vi s hiu ca im gc cao). Lu rng trc khi ra khi chng trnh, phi ghi s liu bnh sai li vo my tnh, bng cch g Y vo cu hi: DO YOU WANT TO SAVE THE NETWORK TO DISK BEFORE EXIT?. VI. Bin tp kt qu Kt qu tnh cao Elippsoid c lu trong file Network.txt thuc th mc C \ GPSURVEY \ PROJECTS \ HANOI \ GEOIDNET \GMOD. Copy Network.txt vo th mc cha kt qu bnh sai li GPS (C \ GPSURVEY \ PROJECTS \ HANOI \ NETADJ) v thc hin quy trnh bin tp thnh qu bnh sai nh sau (theo chng trnh ca Tin s Nguyn Vn Vn, Trng Phng Trc a - a hnh ): 1. Copy file KQ_GPS.EXE vo GPSURVEY \ PROJECTS \ NETADJ 2. Tnh khp hnh cho tt c cc tam gic c th c trong s o ni v ghi kt qu thnh File Khep.log; 3. Vo Utilities \ Project Report (bng 88) c bng 89. Trong bng 89, nh du ( ) vo Detailed Baseline Summary v Summary, ghi tn File ( v tr Title) l Canh.txt v nhp chut vo Text FileBng 88 Bng 89

4. Copy File Scratch.fil trong th mc WINDOW \ TEMP vo GPSURVEY \ PROJECTS \ NETADJ; 5. Chy chng trnh KQ_GPS.EXE: Chng trnh KQ_GPS.EXE gm 2 ch : - bin tp kt qu tnh cnh GPS, a bin s 1;


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- bin tp kt qu tnh ton bnh sai li GPS thnh cc bng, a bin s 2. Nu kt qu c bin tp trong mt th mc ring, cn c cc File sau:Bng 90

Stt Th mc bin tp1 2 3 4 5 6 7 8 9 KQ_GPS.EXE a CD ROOM

Th mc cha File GPSURVEY \ PROJECTS \HANOI GPSURVEY \ PROJECTS \HANOI GPSURVEY \ PROJECTS \ HANOI \ GEOIDNET \GMOD GPSURVEY \ PROJECTS \ HANOI \ NETADJ GPSURVEY \ PROJECTS \ HANOI \ NETADJ GPSURVEY \ PROJECTS \ HANOI \ NETADJ GPSURVEY \ PROJECTS \ HANOI \ NETADJ WINDOW \ TEMP

Khep.log Canh.txt Network.txt Closures.log Coords.log Covar.log Observs.log Scratch.fil

nhn c ta , cao ca li GPS trong cc h thng ta khc (HANOI-72, WGS-84), vn tin hnh theo cch trnh by, sau dng chng trnh CIDALA v DMAVCT20 chuyn ta , cao vo h thng cn tnh. V. Phn Ph Lc Ph lc 1 - Summary - Tm tt kt quFrom Station1100

To Station1095

Solution TypeL1 fixed

Slope Distance (meters)7336.825

Ratio24.5

Reference Variance0.203

From Ant. Ht To Ant. Ht. meas. meters meas. meters1.190 1.450

Ph lc 2 - Processor controls: Kim tra qu trnh s lProcessor Controls: [General] Process start time: Process stop time: Elevation mask: Maximum iterations: Maximum fixable cycle slip: Ephemeris: Residuals: Antenna phase correction: [Observables] L1 phase L1 C/A code [Static Network] Baseline generation: Min baseline observation time [Quality] Observation editing: Ratio test: Reference variance test:

3/3/04 02:38:00 GPS (1260 268680) 3/3/04 05:02:10 GPS (1260 277330) 15 degrees 10 600 seconds Broadcast Enabled Enabled Enabled Enabled All baselines 600 seconds Edit multiplier Cutoff Level of confidence 3.5 1.5 0.950


28

[Tropo Correction] Model: Estimated zenith delay interval: Use observed mets: [Iono Correction] Correction: Applied to: Application threshold: [Final Solution] Final solution type: [Satellites] Disabled:

Hopfield 2 hours Enabled Ambiguity Pass Broadcast Model Static, Kinematic 10 kilometers L1 Fixed Final Pass Broadcast Model Static, Kinematic 5 kilometers

Ph lc 3 - Station Tracking summary: Tm lc thng tin trm o

Ph lc 4 - Combined tracking summary: Tm lc thng tin lin kt trm o

Ph lc 5 - Residuals: Phn tha


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VI. Thit k, o c v tnh bnh sai li GPS VI.1. Li GPS Li GPS l dng li trc a khng gian v thc cht li lin kt cc im trn mt t thng qua cc im bit ta khng gian: cc v tinh. Tr o trong li GPS chnh l cc khong cch t cc im quan st n cc v tinh. Li GPS c o theo phng php tng i xc nh cnh gia cc im trn mt t. u im ca li GPS l khng cn thng hng gia cc im trn mt t m ch cn c thng thong trn bu tri my thu c th thu c tn hiu t cc v tinh mt cch thun li. Li GPS l mt trong nhng phng php xy dng li ta , khi thit k li cn nm vng cc quy nh k thut trong cc quy phm hin hnh thit k li GPS tho mn cc yu cu v chnh xc cc yu t ca li trc a n m nhim v thc hin c cc quy nh k thut ring ca cng ngh o GPS. VI.2. Thit k li GPS Li khng ch GPS c xy dng phc v cho cc mc ch khc nhau ca thc t. Ty thuc vo chnh xc xc nh cp hng li, xy dng quy trnh o c v tnh ton cho ph hp. Tuy nhin, d cp hng no th li GPS cng c thit k da trn cc nguyn tc chung sau: - hnh li: Thit k theo cc kha tam gic, t gic hoc ti a l ng gic. - Xut pht t cc im gc phi c t nht 3 hng n cc im trong li. Trng hp c bit kh khn (nh li khng ch cu, hm) c th ch c 2 hng. Tuy nhin trong trng hp ny phi rt ch n quy trnh o c (thi gian o, chn v tinh) v tnh ton. - Cc im gc phi c phn b u trong ton li. Khong cch t gc n gc ph thuc vo cp hng li v theo quy nh ca quy phm. Tt nht l cc im gc phi c khng ch cc bin ca li. - S chnh lch v di gia cc cnh v ln ca cc gc khng nn vut qu quy nh ca li truyn thng. VI.3. Chn im GPS im GPS l im ta , khi chn cn tho mn cc yu cu chn im mt phng ni chung, ng thi cn tho mn cc yu cu sau: - Trong phm vi gc ng 15o t im t my ti bu tri (gc ngng) khng c chng ngi vt nh tn cy, nh cao tng - im GPS cn chn cch xa i pht sng 500 mt v xa ng in cao th 50 mt trnh nhiu; - Li GPS xy dng mi cn c t nht 2 im ta Nh nc cp cao hn v 2 im cao thy chun ri u trn khu o tnh chuyn ta WGS-84 v ta Nh nc v chuyn cao trc a v cao thy chun. - V nguyn tc, gia cc im GPS khng cn thng hng nhng thun tin cho vic pht trin xung li cp thp, cc im GPS nn cn nhng cp thng hng. - Cc im nn chn ni n nh v a hnh, d dng i li, tm kim nhng phi bo v lu di. - Nn chn nhng khu vc c kh nng o dn thy chun hnh hc. - Khi chn cn lu ti s lin kt gia cc mng li c v mng li mi.


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VI.4. Lp phng n b tr v thi cng li T gc o li, c th coi li GPS l li o cnh tng ng. Cc cnh ni gia 2 im c chnh xc biu th bng cng thc:

= a 2 + b2D2Trong : - D - chiu di cnh; - a - sai s c nh; - b - sai s bin i trong sai s c trng ca my thu. Thng thng mi loi my c cch thit k ring, nhng trong thc t khi b tr li GPS cng ging nh cc loi li khc v im gc khi tnh mt phng, cao Nh nc; v s lin kt vi cc li c, v chn mc Li phi c thit k to thnh cc vng khp kn hoc dng ng chuyn ph hp gia cc im cp cao. S lng im cp cao ph thuc vo tnh hnh thc t, nhng ni chung mi khu o khng t hn 2 im khi tnh. Khi thit k phi tn dng cc im trong h thng im c c trong khu o. Khi o GPS xy dng li ta thng o theo phng php o tnh, o tng i nn t nht phi c 2 my thu tr ln ng thi thu tn hiu v tinh (session). Hai my o trong mt session to thnh 1 cnh o. Cng nhiu my o ng thi th s lng cnh cng ln v tt nhin iu kin kim tra cng nhiu. VI.5. Lp k hoch o T thi gian d nh o, v tr a l khu o, lch v tinh gn ng v cc tham s la chn nh suy gim chnh xc v tr im PDOP, gc ngng, s lng v tinh thu c trong mt session vi phn mm km theo my ta bit c cc khong thi gian thu tn hiu tt nht trong ngy. lp lch thng ly ta trung tm khu o. Trong mt s trng hp khu o tri di (chnh l giao thng) th nn ly ta hai u khu o lp lch, sau ly gi tr trung bnh kt qu. Thi gian thu tn hiu ti mi im ph thuc vo phng php o, khong cch o v chnh xc cn t c. T cc khong thi gian o tt nht ngi ta lp ra k hoch di chuyn my hp l m bo cht lng o v thc hin c phng n b tr v thi cng li. VI.6. Kim tra cht lng o cnh Tu theo chiu di cnh m kim tra cc ch tiu chnh xc o cnh RMS, suy gim chnh xc hnh hc GDOP, t s RATIO ca cc cnh. Khi cc quy nh trn vt qu 1,5 ln ngi ta xc nh li cc tham s chn lc nh nng cao gc ngng, chn s v tinh kho tnh li cc cnh. Nu tnh li m ch tiu khng t th phi o li. Tu chiu di cnh m chn li gii thch hp, thng cnh ngn hn 10 km nn chn li gii Fixed, cnh di chn li gii Float (sai phn bc 2 hoc 3). Da vo kt qu tnh cnh vi cc s gia ta x, y, z ca cc cnh ngi ta tnh sai s khp ta ca cc vng khp v tnh sai s khp tng i. Nu cc ch tiu k thut ny t yu cu th chun b tnh ton bnh sai bng cch chuyn tr o v mt quy chiu. Cc ch tiu nh gi chnh xc cng tu thuc vo chc nng o v cu to my v phn mm tnh ton x l s liu. Vic kim tra phi tin hnh ngay ti thc a tt nht l sau hng ngy i o v.


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Tnh khi lc cnh o GPS quyt nh cht lng ca li. V vy i hi ngi tnh phi rt cn thn trong tng giai on tnh. i vi tng Session, ngi tnh nn lp bng theo di kt qu trong ton b giai on tnh nh sau:Stt Ngy Ses1 13/8 1

SH1234 5678 8765 4321

Ant.o1.345 1.456 1.567 1.678

Ant.tnh Tg o1.344 1.455 1.566 1.677 11 20 13 42h h

Tg tnh S o ni11 30 13 30h h

c imB SV15, 27 B ng cho 1234 -8765

Ghi ch

2

VII.3.6. Bnh sai kt qu o Thng thng, km theo my thu c phn mm bnh sai kt qu o v nh gi chnh xc cc yu t ca li v tnh chuyn ta , cao v h ta s dng. Cc phn mm thng dng Vit Nam: fillnet, Trimvec, GPsurvey, Trimle Geomatic..v.v. Mi phn mm u c nhng u nhc im ca n, nhng ni chung cc phn mm ra i sau tt hn v bao qut hn. Chng trnh bnh sai thng thc hin qua 3 giai on: - Kt ni tt c cc vect vo mt li thng nht; - Bnh sai cc vect v hiu chnh vo cc thnh phn ca li; - Tnh ton v chuyn i cc loi ta v cao im; Trc tin bnh sai t do mng li mt phng trong h ta WGS-84, pht hin cc sai s th, loi b nhng vect c sai s ln. Cc phn mm x l s liu GPS u cho php bnh sai li theo phng php s bnh phng nh nht. Kt qu bnh sai cho nhng thng tin tng hp v cht lng li. Tnh ton cao trong li GPS kh phc tp v cao o trong GPS l cao c tnh ton hc (ellipsoid), trong khi cao thy chun chng ta thng dng l cao mang tnh vt l (geoid), v vy mun tnh chnh xc cao thy chun cn phi c m hnh Geoid chun. nhng vng chnh lch gia ellipsoid v geoid nh hoc l bin ng u th chnh xc cao bng GPS c th t ti dm. Hin nay trong iu kin tt ta c th xc nh cao GPS tng ng hng IV Nh nc khc phc nhng sai st trong tnh ton v bnh sai nht thit phi c mt im gc mt phng v cao Nh nc. Cc im gc phi phn b u trn khu o.


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