DATN VAI TRÒ CỦA LỊCH VỆ TINH CHÍNH XÁC TRONG XLSL GNSS
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Transcript of DATN VAI TRÒ CỦA LỊCH VỆ TINH CHÍNH XÁC TRONG XLSL GNSS
KHUNG V H THNG THAM CHIU MT T
PAGE
,
X
MC LC
mc
Danh mc cc k hiu vit tt, k hiu ting anh
Danh mc cc bng biu
Danh mc cc hnh v
M U
CHNG 1. QUY TRNH S L S LIU LI GNSS
1.1. Quy trinh x ly s liu li GNSS
1.1.1. S quy trnh o c thnh lp li bng cng ngh GNSS
1.1.2. Quy trnh s l li bng cng ngh GNSS
1.1.2.1. Ci t phn mm s l s liu GNSS
1.1.2.2. Trt s liu o
1.1.2.3. X l vc t cnh
1.1.2.4. X l s liu
1.1.2.5. Kim tra nh gi cht lng o li bng cng ngh GNSS
1.1.2.6. Bnh sai li GPS
1.1.2.7. Tnh chuyn kt qu o GPS
1.1.2.8. Tnh i gia ta trc a v ta vung gc phng
1.1.2.9. Xc nh 7 tham s chuyn i ta gia hai h quy chiu
1.2. Phn mm x ly s liu li GNSS
1.2.1. Gii thiu tng quan v phn mm x l Trimble Business Center 2.0
1.2.2. Ci t Trimble Business Center 2.0
1.2.3. Nhp m hnh Geoid
1.2.4. Thit lp h ta a phng
1.2.5. Khai bo h ta a phng
1.2.6. Lm vic vi Project
1.2.7. Nhp d liu cho x l sau
1.2.8. X l cnh trong phn mm Trimble Business Center 2.0
1.2.9. Bnh sai li
CHNG2. LICH V TINH
2.1. Khai quat v lich v tinh
2.1.1. Cc h thi gian
2.1.2. Qu o v tinh
2.1.2.1. Miu t qu o
2.1.2.2. Thng bo qu o
2.1.3. nh hng chnh xc ca lch v tinh n kt qu o GPS
2.1.4. Lch v tinh d bo
2.1.5. Lch v tinh qung b
2.2. Lch v tinh chnh xc
2.2.1. Qu trnh hnh thnh v pht trin lch v tinh chnh xc
2.2.2. Cu trc ca lch v tinh chnh xc
CHNG 3. THC NGHIM
3.1. Li thc nghim
3.1.1. Thi cng li
3.1.2 o li
3.2. X ly s liu
3.2.1. Ni dung cng vic v cc bc thc hin
3.2.2. Qu trnh x l
3.3. Kt qua thc nghim
KT LUN VA KIN NGHI
DANH MC TI LIU THAM KHO
Ph lc 1: Kt qu bnh sai lch v tinh qung b
Ph lc 2: Kt qu bnh sai lch v tinh chnh xc
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DANH MUC CAC KY HIU VIT TT, KY HIU TING ANH
GNSS (Global Navigation Satellite System)
H thng v tinh dn ng
GPS (Global Positioning System)
H thng nh v ca M
GLONASS (Global Navigation Satellite System)
H thng nh v ca Nga
GALILEO
H thng nh v ca Chu u
IGS (International GNSS Service)
Dch v GNSS quc t
VN - 2000
H ta quc gia hin nay ca Vit Nam
UTM (Universal Transverse Mercator)
Li chiu hnh tr ngang ng gc
ITRF (International Terrestrial Reference Frame)
Khung tham chiu Tri t
Rinex (Receiver Independent Exchange Format)
Tp trao i gia cc nh dng
cao ngten (Antenna height)
cao tnh t tm mc ti tm pha anten
Broadcast Ephemeris hoc Broadcast Ephemerides
Lch v tinh qung b
Precise Ephemeris hoc Precise Ephemerides
Lch v tinh chnh xc
Single differential
Sai phn n
Tripel differential
Sai phn bi
Double differential
Sai phn kp
Observation session
Ca o
DANH MUC CAC BANG BIU
Bng 1.1. Sai s khp tng i cho li hng II v hng III
Bng 2.1. Khi qut v lch v tinh
Bng 2.2. Cc h thi gian
Bng 2.3. Cc thi im chun
Bng 2.4. Sai s lch v tinh
Bng 2.5. Lch v tinh d bo
Bng 2.6. Lch v tinh qung b
Bng 2.7. Qu trnh pht trin lch v tinh chnh xc
Bng 2.8. Mt phn tp lch .sp3
Bng 2.9. Cc m t c bn v cu trc .sp3
Bng 3.1. Tng hp cc tp s liu o
Bng 3.2. nh gi chnh xc v cc ch tiu
Bng 3.3: lch ta vung gc khng gian sau bnh sai
Bng 3.4: chnh lch sai s trung phng v tr gia cc im
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DANH MUC CAC HINH VE
Hnh 1.1. S quy trnh o c ngoi thc a bng cng ngh GNSS
Hnh 1.2. S quy trnh s l s liu li GNSS
Hnh 1.3. Kt ni my thu GPS vi my tnh
Hnh 1.4. Nguyn tc tnh thi gian chung
Hnh 1.5. S v tinh tham gia tnh cnh
Hnh 1.6. Quan h gia hai h quy chiu
Hnh 1.7. Giao din bt u ci t phn mm
Hnh 1.8. Nhp m hnh Geoid mi
Hnh 1.9. Ca s Coordinate System Manger
Hnh 1.10. Thit lp cc tham s tnh chuyn h ta
Hnh 1.11. t tn h ta
Hnh 1.12. Ci t cc tham s mi chiu cho h ta phng
Hnh 1.13. To mi mt Project lm vic
Hnh 1.14. Nhp d liu
Hnh 1.15. Hp thoi Rew Dat Check In
Hnh 1.16. Mn hnh s l ca phn mm Trimble Business Center 2.0
Hnh 1.17. Dao din chy cc vect cnh
Hnh 1.18. Nhp ta im gc vo trong mng li
Hnh 1.19. Kt qu bnh sai di dng file .html
Hnh 2.1. Mng li trm thu GNSS ca trung tm dich v GNSS quc t
Hnh 3.1. hnh thc nghim o GPS
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M U
Ngy nay xu th ton cu ha nn kinh t th gii, khoa hc cng ngh pht trin mt cch nhanh chng, cc cng ngh cao nh cng ngh thng tin, cng ngh sinh hc, cng ngh nano, cng ngh hng khng v tr tr thnh mi nhn cho s pht trin mnh m khoa hc cng ngh v s t bin ca nhiu quc gia.
Cng tc trc a thc cht l xc nh v tr ca tt c cc im tc l xc nh gi tr (x,y) hoc (h), vic xc nh chnh xc cc im i hi chng ta phi p dng nhng thnh tu khoa hc cng ngh, mt trong s chnh l cng ngh v tinh dn ng ton cu GNSS.
H thng v tinh dn ng ton cu GNSS ra i gip vic xc nh v tr cc im trn mt t mt cch d dng, nng cao chnh xc nh v GNSS c rt nhiu phng n chng hn nh hn ch nh hng ca tng in ly, tng kh quyn, xy dng m hnh trng trng tri t vi chnh xc cao trn khu vc xc nh, Vic s dng lch v tinh chnh xc ng vai tr quan trng trong cng tc x l s liu t c chnh xc cao trong vic xc nh v tr im. V vy em xin php chn ti vi tn gi Vai tro cua lich v tinh chinh xac trong x ly s liu GNSS ti ny s cho thy nh hng ca lch v tinh chnh xc n vic x l s liu GNSS.
Ni dung ca n c ban c trnh by trong ba chng:
Chng 1. Quy trnh s l s liu li GNSS.
Chng 2. Lch v tinh.
Chng 3. Thc nghim.
hon thin an bn thn em khng ngng hc tp, tm hiu qua sch bo va internet. Trong qu trnh thc hin, em nhn c s gip ca cc thy c gio, c bit l c gio ThS. Bi Th Hng Thm v thy gio TS. Vy Quc Hi ngi hng dn, ch bo tn tnh em trong sut thi gian qua. Mc d rt c gng xong do thi gian v kin thc cn hn ch nn trong ni dung n chc chn khng trnh khi nhng thiu st, em rt mong c s ch bo ca cc thy c gio bi n ca em c hon thin hn.
Em xin chn thnh cm n!
H Ni, ngy thng 6 nm 2014
Sinh vin thc hin
Thnh Chung
Chng 1
QUY TRINH X LY S LIU LI GNSS
1.1. Quy trinh x ly s liu li GNSS
1.1.1. S quy trnh o c thnh lp li bng cng ngh GNSS
,
Z
1.1.2. Quy trnh s l li bng cng ngh GNSS
,
Y
1.1.2.1. Ci t phn mm s l s liu GNSS
Ty theo nhu cu ca tng ngi s l s liu m ta la chn phn mm x l cho ph hp vi mc ch sn phm p ng nhu cu cng vic. Hin nay trn th trng c rt nhiu phn mm s l s liu o GNSS trong phi k n cc phn mm kh thng dng ca hng Trimble (M).
- Trimble Business Center
- Trimble Total Control
- Trimble Geomatic Office
1.1.2.2. Trt s liu o
Cc my thu GPS loi mi nht hin i nht hin nay u cha s liu quan trc vo b nh trong, trong khi cc my thu c hn li ghi s liu vo a mm hoc bng t. Bc u tin trong cng tc x l s liu o chnh l cng tc trt s liu t cc my thu vo a cng ca my tnh. Vic trt s liu c thc hin nh phn mm ca hng ch to my thu cung cp v d nh modul c lp dng trt s liu GPload ca hng Trimble hoc Trimbl Geomatic Office, s dng modul trt s liu Data Transfer cho my thu R-3. i vi cc my thu ca hng TOPCON s dng modul TOPCON LINK trt s liu. Cn lu ti cng trt s liu v cp trt s liu. Cc my thu GNSS th h mi c cng giao tip vi my tnh qua cng USB (hnh 1.3).
Hnh 1.3. Kt ni my thu GPS vi my tnh
Mt s my GPS c nh Trimble 4600LS c cp trt s liu giao tip vi my tnh qua cng COM, hin nay nhiu my tnh th h mi khng c cng COM, ch yu l cng USB. Cn c b chuyn i COM-USB khi trt s liu cho loi my thu ny. S liu trt t my thu vo my tnh gm cc tr o pha L1 hoc L1 v L2, cc tr o khong cch gi C1 hoc C1, P1, P2. Vi mt s my thu cn km theo tr o Doppler D1 D2. Trong tp s liu o cn c to gn ng (X,Y,Z) ca im t my cng vi s hiu im, cao anten nhp t khi khi ng my (nu c). Ngoi s liu o, s liu c trt vo cn c tp lch v tinh qung b phc v cho cc tnh ton tip theo. C mt s my thu khng c thao tc vo tn im v cao anten thc a (nh my Trimble 4600LS) th trong giai on trt s liu s phi lm th tc ny. i vi cc my thu nhp tn im trm my, cao anten ngay ti thc a, th cn kim tra li cc d liu vo. Nu pht hin thy sai cn chnh sa ngay. cao anten c th nhp l cao ng (True Vertical) v cng c th nhp vo cao o (Uncorrected Vertical) ph hp vi chng loi anten v cch o quy nh. Khi o cao anten chng ta cn o chnh xc n 1mm nhng nu nhp sai chng loi anten hoc sai kiu o cao anten th s gy ra sai s c vi cm hoc ln hn trong kt qu cui cng.
Trong khi trt s liu cn c s o hoc bng tng hp ghi chp ti cc trm my. Vic trt s liu c th cn c vo thi gian bt u, thi gian kt thc v cn c to a l ca im o pht hin nhng nhm ln v tn im. Ni chung cc tp s liu o thu c cn lu ngay vo thit b trung gian nh USB, CD,... Tt nht nn c b nh trung gian c dung lng ln ghi cc s liu o ngay sau khi trt nhm bo m an ton d liu o.
1.1.2.3. X l vc t cnh
Ty thuc vo phng php o, o tnh, tnh nhanh hay o ng, vic x l tnh cnh s c thc hin da trn c s thi gian chung v v tinh chung i vi hai my thu. Khong thi gian chung khi o tnh c th hin trn hnh sau:
,
Z
Hnh 1.4 . Nguyn tc tnh thi gian chung
Trn hnh 1.4 th hin khong thi gian thu tn hiu ca my thu 1 v my thu 2 l
1
t
D
v
2
t
D
, trong :
2
T
4
T
t
1
-
=
D
;
1
T
3
T
t
2
-
=
D
(1.1)
trong o: T1 v T3 l cc thi im bt v tt my thu 2, T2 v T4 l cc thi im bt v tt my thu 1.
Thi gian chung c s dng tnh cnh l:
2
T
3
T
t
)
2
1
(
-
=
D
-
(1.2)
Thi gian chung s tnh t thi im ca my thu bt ln n thi im my thu tt ca hai my trong cng ca o. Nh vy trong khi thu tn hiu nn ng thi bt my v ng thi tt my trong ca o . Khi tnh cnh, ch c nhng v tinh c s liu ghi trong hai tp ca hai my cng ca o mi c gi tr tham gia tnh cnh. S v tinh chung c m t trn hnh 1.5. Trong trng hp ny, ti my thu 1 nhn c tn hiu ca 8 v tinh (1, 2, 3, 4, 5, 6, 7, 8), cn my thu 2 nhn c tn hiu ca 7 v tinh (3, 4, 5, 6, 7, 8, 9). S lng v tinh chung tham gia tnh cnh s l 6 gm cc v tinh sau 3, 4, 5, 6, 7, 8. Nh vy, cn phi bo m sao cho cc my thu trong mt ca o, c s v tinh c quan st ng thi cng nhiu cng tt. bo m iu kin trn cn lu ti tnh trng che chn tn hiu ti cc trm my. Khi chiu di cnh cng ln (c hng trm, hng ngn km) th s v tinh chung cng t.
,
0
Hnh 1.5. S v tinh tham gia tnh cnh
1.1.2.4. X l s liu
Trong mi trng hp o li vic x l s liu o v kim tra cht lng o phi thc hin thng xuyn, t nht l 1 ln trong ngy. Khng nn dn s liu ca nhiu ngy o ri mi x l. Trong o GPS thng xy ra hin tng trt chu k (Cycle Slip) ca tn hiu. Vic kim tra s liu gip pht hin hin tng trt chu k v hiu chnh ngay. Vic hiu chnh ny khng th thc hin khi my thu thc hin m ch c th thc hin trong qu trnh trt v kim tra s liu. Vic kim tra cht lng s liu l bc khi u trong s l vect cnh trong iu kin d ngoi trc khi kt thc cng vic ngoi thc a. X l vector cnh ngoi thc a cho php ta kt lun v cht lng o trc khi kt thc cng vic.
X l o tnh: Cc phn mm hin nay cho php x l nhiu tp s liu o ng thi tnh cnh. Thng thng s liu o ca 1 ngy c quy vo trong 1 th mc a cng cn phn mm x l li trong th mc khc v c ng dn trng trnh nhn v x l. C 2 dng phn mm s l l: 1- tng vect, 2- cc li gii cho tng im. Phn mm x l tng vect cnh trc y c s dng rng ri xong hin nay ngi ta thng x dng phn mm x l nhiu im. c mt s trng hp mt trong cc im trong ca o khi quan trc b hng s liu v tt c cc im c x l ng thi, cc sai s ca im hng s nm trong tt c cc vect v sai s s c gi li. Phn mm x l vect n l cho php kim tra tt hn nhng cnh sai hay im sai. im sai d dng pht hin nh s liu thng k nh: Sai s trung phng trng s n v, sai s tiu chun (bng cch i chiu tham s ca cc cnh c coi l chun vi cc cnh khc). Thm vo , c th ly tng gia s ta theo mt tuyn ca ca o nu nh tng gi tr s gia ta theo vng khp khng nh th chng t mt trong cc im ca ca o c iu kin o km.
Vic x l bng phn mm cho tng vect c thc hin theo trnh t sau:
1. To cc tp qu o.
2. Tnh gi tr tt nht v tr im theo phng php gi khong cch.
3. c pha sng ti to s liu pha (khng hiu s) v s liu qu o v tinh.
4. To hiu pha v tnh cc hiu chnh khc
5. Tnh gi tr c lng vct s dng sai phn bc 3. Phng php ny cho php pht hin v b li hin tng trt chu k nhn c kt qu tt nht.
6. Tnh ton li gii sai phn bc 2 xc nh vect v gi tr (thc) ca pha.
7. c lng s nguyn a tr ca pha tnh c t bc trc, c th tip tc tnh tip s nguyn a tr chnh xc.
8. Tnh ton sai s li gii da vo s nguyn a tr chnh xc nht c tnh bc trc.
9. Tnh ton tip mt s kt qu khc, s dng s nguyn a tr khc i mt cht (khc i 1) t cc gi tr chn.
10. Tnh t s Ratio l mi quan h gia phng sai ca li gii tt nht vi k n (ch p dng cho li gii fixed). T s ny phi t nht t gi tr l 2 hoc 3 nh vy mi c tin cy i vi kt qu cui cng.
nhn c kt qu tt ngi lm cng tc x l s liu thng c thc hin qua 2 bc sau:
Bc 1: X l theo cc tham s mc nh ca phn mm.
Trong bc ny, s s dng ton b tr o trong thi gian quan trc ca o, s dng tt c cc s liu ca cc v tinh quan st gii cnh, thng thng qua bc x l ny a s cc cnh cho kt qu tt, tr nhng trng hp ti nhng trm o c vn nh b che chn, c cc tc ng nhiu, a ng dn,
Bc 2: i vi nhng cnh khng t trong bc 1, cn x l li ch can thip. Trong bc ny, ngi x l c th ct b nhng v tinh c du hiu xu iu ny c th nhn bit khi xem kt qu gii cnh, cng c th ct b thi gian u hoc cui, tng gc ngng trn 15 ,
X l o ng: Cc bc c bn trong x l kt qu o ng tng t nh i vi o tnh. Cc tp s liu c nhp t my thu vo my tnh cn c kim tra tn tp v cao anten. Trong tnh ton c th c nhng im khc ty thuc vo phn mm s dng. Vic kim tra ch yu i vi cc vect ng l tnh ton cc v tr ca my ng v kim tra s ph hp ca kt qu nhn c t mt vi ln o ring r ti cng mt im. Trong trng hp ny nn c mt vi im bit ta dng so snh vi kt qu o ng l phng php kim tra tt nht.
1.1.2.5. Kim tra nh gi cht lng o li bng cng ngh GNSS
Sau khi tnh ton baseline cn phi kim tra cht lng tr o. Vic kim tra c th thc hin trn 2 ni dung sau:
- Phng sai chun (variance) l sai s trung phng trng s n v ca li gii cnh. Phng sai chun cng l c s nh gi cht lng li gii v n l s khng c n v. Trng hp l tng phng sai chun bng 1, phng sai chun cng ln th cht lng li gii cng km, thng thng i vi my thu mt tn s c th chp nhn phng sai trong khong t 1 n 8 hoc 9, cn i vi nhng cnh di th gi tr phng sai chun cng ln. Trong trng hp o ng (ch c t nht hai ln ghi s liu) c th chp nhn phng sai ln hn, khong 5 hoc 6. Nu phng sai qu ln, c th b nhng sai s nh:
+ S liu b nhiu (do cy, vt cn che chn tn hiu hoc v tinh qu gn ng chn tri)
+ C du hiu ca sai s nguyn a tr
+ C sai s h thng do s dng my thu mt tn s trn khong cch di, khi chu nh hng ca tng ion.
+ Chn ci t li gii fixed khng ng
- T s Ratio cng ln th li gii cng tt v ngc li.
- Dng li gii: Khi Ratio ln n gii hn th s c li gii fixed (li gii c nh), nu Ratio nh hn gii hn th ch nhn c li gii float (li gii ng), tt nht khng chn li gii float.
Trc khi bnh sai li cn kim tra cht lng li. Li GPS c to thnh t nhiu vect cnh. Nu tt c cc cnh u t ch tiu ca cht lng cnh ring r th thng thng ton b li s t yu cu. Nh ni phn trc, trong li GPS, cc vect cnh thng c o khp kn (c th l cc vect cng ca o, hoc khc ca o). Da vo c im kt cu hnh hc ny kim tra cht lng o ca cc vect cnh trong mng li nh tnh ton cc sai s khp hnh. Tng t nh sai s khp hnh trong mng li tam gic o gc, cc sai s khp hnh trong li GPS cng mang tnh cht ca sai s thc ca hm cc tr o.
Vic tnh sai s khp hnh trong li GPS c thc hin trong cc hnh khp kn theo cng thc sau:
i
n
i
X
X
f
D
S
=
=
1
;
i
n
i
Y
Y
f
D
S
=
=
1
;
i
n
i
Z
Z
f
D
S
=
=
1
(1.3)
Sai s khp ton phn c tnh:
2
Z
2
Y
2
X
)
Z
,
Y
,
X
(
f
f
f
f
+
+
=
(1.4)
Sai s khp fX, fY, fZ thc cht l hm ca cc tr o X, Y, Z (l cc thnh phn ca vect cnh) .
Sai s khp tng i c tnh:
T
1
D
f
)
Z
,
Y
,
X
(
=
(1.5)
trong
D
l tng chiu di cnh trong vng khp
Da vo cc hnh khp kn s tnh c sai s khp hnh theo cc cnh o. Nu cc cnh c xc nh trong 1 ca o th s tnh c sai s khp cng ca o. Nu cc cnh khc ca o th s tnh c sai s khp khc ca o. Sai s khp cng ca o thng nh hn sai s khp khc ca o.
Thng thng vic kim tra sai s khp hnh trong li c thc hin nh chc nng sn c ca phn mm s l s liu GNSS.
Theo quy chun k thut ca nc ta, sai s khp tng i cho li hng II v hng III quc gia phi tha mn quy nh sau:
Bng 1.1. Sai s khp tng i cho li hng II v hng III
Tng chiu di vng khp [D]
Hng II
Hng III
Z
(1.14)
hoc
Z
)
B
ctg
e
1
(
ctgB
.
a
e
D
ctgB
2
1
)
1
k
(
2
2
)
1
K
(
2
)
k
(
-
-
-
+
-
-
=
nu D
Z
(1.15)
Trong k l ch s ln tnh lp:
2
2
Y
X
D
+
=
(1.16)
V tr ca nc ta c v nh hn 230 nn D>Z do ta s s dng cng thc (1.14) tnh B.
Khi tnh lp v B theo cng thc (1.14), (1.15) ta ly gi tr gn ng u tin
0
B
theo cng thc:
Z
)
e
1
(
D
ctgB
2
0
-
=
(1.17)
kinh L c tnh theo cng thc:
X
Y
tgL
=
(1.18)
cao trc a H c tnh theo cng thc:
B
sin
e
1
a
N
N
)
e
1
(
ecB
cos
Z
N
B
sec
D
H
2
2
2
-
=
-
-
=
-
=
(1.19)
Ngoi ta ta cn mt s cng thc khc c s dng khi tnh i t (X,Y,Z) sang (B,L,H).
1.1.2.8. Tnh i gia ta trc a v ta vung gc phng
* H ta vung gc khng gian v h ta trc a
Bi ton tnh i t h ta trc a (B,L) v h ta vung gc phng (x,y).
Ta im trn mt elipxoid c chuyn v h ta phng theo cng thc sau:
)
b
,
a
,
L
,
B
(
y
y
)
b
,
a
,
L
,
B
(
x
x
=
=
(1.20)
H ta vung gc phng c thit lp theo php chiu hnh tr ngang (Transverse Mercator Projection) theo mi chiu c kinh tuyn trc
0
L
. Cng thc tng qut ca php chiu hnh tr ngang ng gc, vi t l chiu trn kinh tuyn trc l
0
m
c dng nh sau:
[
{
}
]
)
t
t
.
543
t
.
3111
1385
.(
B
cos
.
40320
l
.
B
sin
N
t
)
t
.
2
(
)
t
.
32
1
(
)
t
.
6
1
(
.
28
)
t
.
24
11
.(
.
8
.
B
cos
.
720
l
.
B
sin
.
N
)
t
.
4
.(
B
cos
.
24
l
.
B
sin
N
B
cos
.
2
l
.
B
sin
N
X
m
x
6
4
2
7
8
4
2
2
2
2
3
2
4
5
6
2
2
3
4
2
0
0
-
+
-
+
+
Y
-
-
Y
+
-
Y
-
-
Y
+
-
Y
+
Y
+
+
=
(1.21)
trong
0
X
l chiu di cung kinh tuyn t xch o n v B.
}
{
]
)
t
t
179
t
479
61
.(
B
cos
5040
l
.
N
t
t
.
.
2
)
t
.
8
1
.(
)
t
.
6
1
(
.
4
B
cos
.
120
l
.
N
)
t
.(
B
cos
.
6
l
.
N
B
cos
.
l
.
N
m
y
6
2
2
7
7
4
2
2
2
2
3
5
5
2
3
3
0
-
+
-
+
+
Y
-
+
Y
+
-
Y
+
-
Y
+
=
(1.22)
trong hiu kinh
0
L
L
l
-
=
, vi
0
L
l kinh ca kinh tuyn trung ng:
)
e
1
(
)
B
sin
e
1
(
M
N
tgB
t
2
0
2
2
-
-
=
=
Y
=
0
m
l t l bin dng trn kinh tuyn trung ng. Nu
1
m
0
=
ta c php chiu Gauss- Kriuger, khi
9996
,
0
m
0
=
ta c php chiu UTM mi
0
6
v khi
9999
,
0
m
0
=
ta c php chiu UTM mi chiu
0
3
.
Ta vung gc phng c tnh theo cng thc (1.21) v (1.22) thng c cng thm vo hng s quy c trnh gi tr ta m v trc ta y cn c s hiu mi chiu. Nc ta min bc bn cu cho nn ch cng vo y = 500 km.
* Bi ton tnh i ta vung gc phng sang ta trc a B, L cng thc tnh ta trc a B c dng:
{
}
{
}
)
t
.
1575
t
.
4095
t
.
3633
1385
.(
N
.
m
.
40320
y
M
m
t
t
.
360
)
t
.
3
t
.
5
(
.
180
)
t
.
15
t
.
98
15
(
.
15
)
t
.
71
21
.(
.
12
)
t
.
24
11
(
.
8
.
N
.
m
.
720
y
M
m
t
t
.
12
)
t
1
(
9
4
.
N
m
24
y
M
m
t
N
m
2
y
M
m
t
B
B
6
0
4
0
2
0
7
0
7
0
8
0
.
0
0
4
0
4
0
2
0
0
4
0
2
0
2
0
2
0
3
0
2
0
4
0
5
0
5
0
6
0
0
0
2
0
2
0
0
2
0
3
0
3
0
4
0
0
0
0
0
2
0
.
0
0
0
+
+
+
+
+
-
Y
+
+
-
Y
+
-
Y
-
-
Y
-
+
-
Y
+
Y
-
+
-
=
(1.23)
Cng thc tnh hiu kinh trc a l c dng :
{
}
)
t
720
t
1320
t
662
61
(
N
m
5040
y
B
sec
t
24
t
72
)
t
68
9
(
)
t
6
1
(
4
.
N
m
120
y
B
sec
)
t
2
(
N
m
.
6
y
.
B
sec
M
m
y
B
sec
l
6
0
4
0
2
0
7
0
7
0
7
0
4
0
2
0
0
2
0
2
0
2
0
3
0
5
0
5
0
5
0
2
0
0
3
0
3
0
3
0
0
0
0
+
+
+
-
+
Y
+
-
Y
+
-
Y
-
+
+
Y
-
=
(1.24)
trong
0
B
l v gn ng ng vi chiu di cung kinh tuyn x/
0
m
(
)
2
0
2
2
0
0
0
0
2
2
0
2
0
0
2
2
0
0
0
e
1
B
sin
e
1
M
N
B
sin
e
1
N
e
1
M
B
sin
e
1
a
N
tgB
t
-
-
=
=
Y
-
-
=
-
=
=
v
0
B
ng vi chiu di cung kinh tuyn l x/m0 c tnh theo cng thc sau:
+
+
+
-
=
0
0
0
6
8
0
4
6
0
2
4
2
0
0
0
sin
.
cos
).
cos
cos
.
cos
.
(
.
1
B
B
B
A
B
A
B
A
A
c
m
x
A
B
(1.25)
trong :
....
e
1024
315
A
....
e
2048
735
e
96
35
A
.....
e
8129
3675
e
384
175
e
32
15
A
1
A
A
....
e
16384
11025
e
256
175
e
64
45
e
4
3
1
A
8
8
6
8
6
4
8
6
4
2
,
8
,
,
6
,
,
,
4
0
2
,
,
,
'
0
+
=
+
+
-
=
+
+
-
=
-
=
+
+
-
+
-
=
trong
,
e
l tm sai th hai ca elipxoid, c tnh theo cng thc :
2
2
2
,
b
b
a
e
2
-
=
Trong cng thc (1.25) gi tr c l tm sai th hai ca elipxoid, c tnh theo cng thc:
2
e
1
a
c
-
=
Gi tr
0
B
c tnh theo cng thc (1.25) c n v l radian. Khi tnh ton phi p vic tnh lp v gi tr
0
B
nm c hai v, cng c th p dng cng thc tnh chiu di cung kinh tuyn tm
0
B
theo phng php lp, cng thc c dng:
[
]
B
cos
.
B
cos
....).
B
cos
.
A
B
cos
.
A
B
cos
A
A
(
B
.
A
.
c
m
x
6
8
4
6
2
4
2
0
0
+
+
+
+
+
=
(1.26)
Sau khi tnh c hiu kinh theo cng thc (1.24) tnh ta kinh theo cng thc sau:
l
+
=
0
L
L
(1.26)
trong
0
L
l kinh ca kinh tuyn trung ng mi chiu.
* Tnh chuyn ta gia cc h quy chiu
tnh chuyn ta gia hai h quy chiu cn phi bit 7 tham s chuyn i gia hai h ta vung gc khng gian gm:
- 3 tham s lch gc ta
dZ
,
dY
,
dX
.
- 3 gc xoay Euler.
- H s t l di m hoc
m
d
( m = 1 + dm).
Ngoi 7 tham s trn, trong mi h quy chiu cn phi bit 2 tham s hnh dang kch thc elipxoid thc dng bn trc ln a v dt
a
.
Nu cho ta trc a (
1
1
1
H
,
L
,
B
) ca 1 im trong h 1, cn phi tnh chuyn sang ta (
2
2
2
H
,
L
,
B
) trong h 2, thc hin cc bc nh sau:
1. Tnh chuyn t ta trc a (
1
1
1
H
,
L
,
B
) trong h 1 thnh ta vung gc khng gian a tm trong h 1 l
)
Z
,
Y
,
X
(
1
1
1
.
2. S dng 7 tham s bit chuyn to vung gc khng gian h 1 sang ta vung gc khng gian h 2 theo cng thc sau:
-
-
+
=
1
1
1
x
y
x
z
y
z
2
2
2
Z
Y
X
.
1
e
e
e
1
e
e
e
1
.
m
dZ
dY
dX
Z
Y
X
(1.27)
3. Sau khi c ta vung gc khng gian thuc h quy chiu 2 tnh chuyn sang h ta trc a (
2
2
2
H
,
L
,
B
).
Hnh 1.6. Quan h gia hai h quy chiu
Trong trng hp tnh chuyn ta phng (x,y) t h 1 sang ta phng (x,y) thuc h 2, thc hin vic tnh chuyn sang (B,L,H) ri sang (X,Y,Z). Tuy nhin trong trng hp ny c cao trc a H cn phi bit cao Geoid:
z
g
+
=
+
=
h
N
h
H
(1.28)
trong : h l cao thy chun
z
l d thng cao tnh n mt kvazigeoid
N l d thng cao tnh n mt Geoid
g
h
l cao chun
Trong mt s trng hp khi khng bit 7 tham s chuyn i th phi xc nh 7 tham s . xc nh 7 tham s phi c t nht 3 im c ta vung gc khng gian hoc ta trc a trong c hai h quy chiu.
1.1.2.9. Xc nh 7 tham s chuyn i ta gia hai h quy chiu
Gi s c n im (n 3) ng thi c ta vung gc khng gian a tm c hai h. Gi tr ta ca im i trong h 1 l (Xi,Yi,Zi), trong h 2 l (Xi,Yi,Zi). T ta trong hai h lp c 3 phng trnh chuyn ta t h 1 sang h 2 nh sau:
-
-
-
+
=
i
i
i
x
y
x
z
y
z
i
i
i
Z
Y
X
e
e
e
e
e
e
m
dZ
dY
dX
Z
Y
X
.
1
1
1
.
'
'
'
(1.29)
Ta coi cc phng trnh trn l m hnh ton xc nh 7 tham s, n gin ta k hiu m = 1+
m
d
,t cng thc (1.14) ta lp c h phng trnh sau:
-
-
-
+
=
+
i
i
i
x
y
x
z
y
z
Z
Y
X
i
i
i
Z
Y
X
e
e
e
e
e
e
dZ
dY
dX
V
V
V
Z
Y
X
.
1
1
1
).
d
+
1
(
m
'
'
'
(1.30)
T (1.30) ta bin i v h phng trnh s hiu chnh:
-
-
-
+
-
-
-
+
=
'
'
'
.
.
i
i
i
i
i
i
i
i
i
m
x
y
x
m
z
y
z
m
Z
Y
X
Z
Z
Y
Y
X
X
Z
Y
X
d
e
e
e
d
e
e
e
d
dX
dX
dX
V
V
V
(1.31)
Cc phng trnh s hiu chnh c dng:
+
-
-
-
=
z
y
x
m
z
y
x
i
i
i
i
i
i
i
i
i
Z
Y
X
l
l
l
d
e
e
e
dZ
dY
dX
.
Z
0
X
Y
1
0
0
Y
X
0
Z
0
1
0
X
Y
Z
0
0
0
1
V
V
V
(1.32)
trong
-
-
-
=
'
'
'
i
i
i
i
i
i
z
y
x
Z
Z
Y
Y
X
X
l
l
l
Khi c n im ta lp c 3n phng trnh s hiu chnh,h phng trnh c gii theo phng php s bnh phng nh nht. Sai s trung phng trng s c tnh theo cng thc sau:
[
]
7
3
-
=
n
VV
m
(1.33)
Da vo ma trn nghch o ca ma trn h s phng trnh chun, nh gi chnh xc 7 tham s.
1.2. Phn mm x ly s liu li GNSS
1.2.1. Gii thiu tng quan v phn mm x l Trimble Business Center 2.0
Trimble Business Center 2.0 (TBC) l phn mm x l s liu o c mnh nht ca hng Trimble. Phn mm ny c nhng cng c cho php x l, phn tch v lp bo co t mt khi lng s liu rt ln.
Cc c bit ca phn mm:
- X l cnh o GPS, GLONASS.
- X l s liu o tnh, tnh nhanh, o ng v o ng lin tc.
- H tr cho s liu GPS th thu c t cc my ca cc hng khc nhau.
- X l c tr o 1 tn s v 2 tn s.
- To cc bng bo co linh hot.
- Tm ra cc sai s th trong cc tr o.
- Xut ra cc nh dng ph hp vi nhiu phn mm nh Autocad, MicroStation SE, ...
- Phn mm Trimble Business Center 2.0 c kh nng nhn s liu o c t cc thit b o c ca Trimble gm c thit b TSC2 chy phn mm Trimble Survey Controller hoc Survey Pro, cc my ton c in t: S6, 5600, 3600, 3300 v my thu chun s DiNi. Hn na, n cn chp nhn s liu GPS th t cc my thu ca cc nh sn xut khc. Phn mm TBC chy trong h iu hnh Windows XP (32 bit, SP3, 64 bit, SP2), Windows Vista hoc Windows 7.
My tnh ci t phn mm TBC cn c cu hnh nh sau:
- RAM: Khng t hn 2GB.
- Dung lng cng: Khng t hn 5GB.
- Cn c Microsoft. NET Framework 3.5 tr ln.
1.2.2. Ci t Trimble Business Center 2.0
ci t Trimble Business Center 2.0 trn my tnh, a a CD-ROM c phn mm ci t vo CD-ROM. Phn mm s t ng c ci t. Chng trnh s hng dn trong sut qu trnh ci t. B ci t y ca Trimble Business Center 2.0 cn khong 357MB dung lng a trng trn a ci t.
Giao din ci t phn mm Trimble Business Center 2.0 c dng:
Hnh 1.7. Giao din bt u ci t phn mm
Phn ci t trn l phin bn TBC 2.0, ta dng phin bn ny bnh sai kt qu vn chnh xc. Nu TBC 2.0 c s c li thot khi trng trnh ang s dng hoc mt vi l do g ta c th nng cp ln cc phin bn mi.
Sau khi ci t xong phn mm tin hnh chy key ca phn mm, trng trnh s dng c chc nng bnh sai li.
1.2.3. Nhp m hnh Geoid
M hnh Geoid s c s dng chuyn cao trc a H v cao thy chun h khi x l li GPS. M hnh Geoid (c dng tp *.ggf), m hnh ny v cng quan trng i vi tng vng, tng lnh th trong cng tc x l s liu.
M hp thoi Coordinate System Manger, khi ta s thy xut hin mt hp thoi hin ra trn nn my tnh:
Hnh 1.8. Nhp m hnh Geoid mi
1.2.4. Thit lp h ta a phng
H toa a phng l h ta ring thng c s dng mi quc gia, mi vng v khu vc khc nhau, thm ch mi cng vic khc nhau. Trong phn ny s trnh by cch thit lp h ta a phng.
Cc bc thit lp c tin hnh t Tools/Coordinate System Manger t giao din chnh ca phn mm. Ca s Coordinate System Manger xut hin v hin th tt c cc h ta c trong file Current theo hnh 1.9.
Hnh 1.9. Ca s Coordinate System Manger
Trong ca s Datum Transformation Properties nhp h ta khu vc cn tnh ton vo, chn Elipxoid ph hp vi khu vc .
Tip theo tin hnh khai bo cc tham s tnh chuyn t h WGS-84 sang h cn tnh chuyn hoc t h cn tnh chuyn sang h WGS-84 nh hnh 1.10.
Hnh 1.10. Thit lp cc tham s tnh chuyn h ta
1.2.5. Khai bo h ta a phng
Sau khi ci t xong cc tham s tnh chuyn ta , chn hp thoi Coordinate System. Kch chut phi vo vng trng bn phi v chn Add New Coordinate Systems Group, Khi xut hin hp thoi.
Hnh 1.11. t tn h ta
Ti ca s ny, ta nhp h thng ta ri chn OK. Tip theo dng chut chn vo h thng ta va thit lp, n chut phi chn Add New Corrdinate System/Transverse Mercator,... Sau Next lin tc cho n khi xut hin hp thoi c dng nh hnh 1.11. khai bo cc thng s cho h ta a phng nh v tuyn, kinh tuyn trc, t l bin dng chiu di trn kinh tuyn trc, hng s cng vo ta x, hng s cng vo ta y.
Hnh 1.12. Ci t cc tham s mi chiu cho h ta phng
1.2.6. Lm vic vi Project
to mi mt Project (mt d n), ta chn File/New Project t ca phn mm hnh 1.13.
Sau khi chn, trn mn hnh s xut hin hp thoi New Project. Trong trng Template tin hnh chn Metric thit lp cc cu hnh Project Metric i vi Project ny v nhn OK. Nu mun ty chn Metric lm mc nh nhn nt Set as defalt.
Hnh 1.13. To mi mt Project lm vic
1.2.7. Nhp d liu cho x l sau
X l sau l cng vic thng p dng x l s liu o li GPS. x l sau, trc ht cn nhp d liu t lnh Import. C th thc hin bng chn File/Import hoc biu tng Import trn thanh cng c. Sau khi chn, hp thoi Improt xut hin hnh 1.14.
Hnh 1.14. Nhp d liu
Trong danh sch Import s dng nt Browse tm n th mc cha d liu c trt vo my tnh. Vic trt s liu t b nh my thu vo my tnh c thc hin trc bng m un trt d liu c sn trong phn mm. S liu m phn mm Trimble Business Center 2.0 nhn c a vo l cc file d liu (*.DAT hoc RINEX). Sau khi nhp ht cc d liu xut hin hp thoi Rew Dat Check In xut hin hnh 1.15.
Hnh 1.15. Hp thoi Rew Dat Check In
Trong hp thoi Rew Dat Check In cho php kim tra v chnh sa d liu th trong mi file trc khi hon thin d liu. Trn hp thoi c 3 th la chn gc di bn tri gm: Point, Antenna v Receiver.
Khi chn Point s cho bit cc thng tin v tn im, tn tp s liu, thi gian bt u v thi gian kt thc,
Khi chn th Antenna s hin th chng loi my thu s dng, im tnh cao anten, cao anten, ti y cho php chng ta sa i cc thng tin nu thy sai st.
Khi chn th Receiver s hin th chng loi my thu s dng, ni ch to, kiu o, s hiu my thu,
Sau khi a ht tt c cc d liu th vao phn mm khi c thy mn hnh Plan View cho php hin th tt c cc cnh trong mng li hnh 1.16.
Hnh 1.16. Mn hnh s l ca phn mm Trimble Business Center 2.0
1.2.8. X l cnh trong phn mm Trimble Business Center 2.0
x l cht lng cc vect cnh trc ht s tin hnh x l tt c cc cnh theo tham s mc nh ca phn mm. Cng c th x l cc cnh theo phng n tng cnh c lp p ng cc ch tiu k thut thit k li.
Khi x l cnh, cn bit ta ta tuyt i ca cc im u cnh. Thng thng ta tuyt i c xc nh t phng php nh v tuyt i. Trong trng hp x l s liu vi chnh xc cao, cn phi nhp ta chnh xc trong h WGS-84 ca t nht mt im trong li.
khi ng chc nng x l cc vect cnh chn Survey/Processing Baselines hoc nhn vo biu tng Process Baselines trn thanh cng c. Trong qu trnh x l hp thoi Process Baselines xut hin (hnh 1.17). Khi qu trnh x l cnh kt thc, kt qu trc khi lu vect cnh c x l.
Hnh 1.17. Giao din chy cc vect cnh
Trong qu trnh x l cnh, c nhiu cnh c cht lng khng c tt (li gii Float). i vi cc cnh ny thng vt hn sai, lc trn mn hnh ngi dng s thy thng bo cc l c, l c my vng th hin rng cc cnh o ang ri vo trong tm gii hn sai m c cho php, cc l c my cho thy c mt hoc vi thng s mc di hn sai. Mun lm mt l c mu vng v mu ta c th t hn sai cao ln nhng gi tr sai s thc s vn gi nguyn (khng lm tng nn chnh xc cht lng cc vect cnh).
i vi nhng cnh c cht lng km mt gii php thng s dng l ct v tinh, tng gim gc ngng, ct b thi gian (x l gi), i vi nhiu phn mm cho php s dng c chc nng thng s lc nhiu gia tng cht lng cnh.
1.2.9. Bnh sai li
Khi tt c cc cnh trong li t yu cu c th tin hnh bnh sai li trong h quy chiu la chn t trc khi bnh sai theo 2 bc sau:
Bc 1: Bnh sai li vi im gc ti thiu.
thc hin bnh sai li th ch cn mt im gc trong h WGS-84 hoc trong h ta a phng. nh du vo im gc cn la chn trn mn hnh v chn Add Coordinate nhp ta v cao thy chun hoc cao trc a. Sau nhp xong cn chn Control Quality phn mm nhn bit c y l gi tr im gc khu vc.
Hnh 1.18. Nhp ta im gc vo trong mng li
Thng sau ln bnh sai th nht, cc kt qu khng t do vn trng s u vo, iu th hin gi tr Reference Factor ca li khng bng 1 v kim nh Chi - Bnh phng (Chi Square) tht bi (Failed). Trong trng hp ny tin hnh tnh ton li cho n khi ch s Reference Factor t gi tr p ng c chnh xc ton b mng li.
Bc 2: Bnh sai vi ton b im gc c trong li
Trong bc ny vic bnh sai cng tng t nh bc 1 ch khc l s dng tt c cc im gc c trong li bnh sai nhm m bo tin cy, chnh xc cho mng li.
Kt qu bnh sai li c lu tr trn trang wed di dng *.html cu trc file d liu ny th hin mi thng tin v kt qu bnh sai. T giao din chnh ca phn mm TBC chn Report/Network Adjustment Report s thy c cu trc file nh hnh 1.19.
Hnh 1.19. Kt qu bnh sai di dng file *.html
Chng 2
LICH V TINH
2.1. Khai quat v lich v tinh
Lch v tinh (ephemeris) l tp hp s liu th hin v tr ca v tinh di dng hm ca thi gian. C 3 loi lch v tinh: Lch v tinh d bo, lch v tinh qung b , v lch v tinh chnh xc. Cc lch v tinh ny khc nhau v chnh xc v thi gian c lch v tinh. Bng 2.1 th hin chnh xc ca cc s liu trn.
Bng 2.1. Khi qut v lch v tinh
Loi lch v tinh
Sai s
Ch
Nin gim (Almanac)
vi km
Ph thuc vo tui ca lch v tinh
Qung b (c SA)
2 - 50 m
Ph thuc vo mc nhiu SA
Qung b (khng c SA)
1 - 5 m
Hoc tt hn
Chnh xc (Precise)
0,05 - 0,2 m
Ph thuc vo khong thi gian so vi hin ti
2.1.1. Cc h thi gian
Thi gian Mt tri v thin vn: o s quay ca Tri t l gc gia kinh tuyn thin th v kinh tuyn chun (chn kinh tuyn Greenwich). Thi gian quc t (UT) c xc nh bi gc gi Greenwich c tng ln bi 12 gi ca chuyn ng qu o ng nht tng tng ca Mt tri trong mt phng xch o. Thi gian thin vn c xc nh bi gc gi ca im xun phn. Ly xun phn trung bnh nh l chun dn ti thi gian thin vn trung bnh v trong im xun phn thc nh l im chun dn ti thi gian thin vn thc. Thi gian Mt tri v thi gian thin vn khng ng nht v vn tc gc
E
w
khng phi l khng i. Nhng giao ng mt phn gy bi nhng thay i trong mmen qun tnh cc thc hin bi bin dng triu cng nh cc vn chuyn khi lng khc. Mt yu t khc gy nn bi nhng giao ng bn thn trc tri t. Trong trng hp ny, thi gian quc t c hiu chnh cho chuyn ng cc k hiu l UT1.
Thi gian ng hc: H thi gian c suy t cc chuyn ng hnh tinh trong h Mt tri c gi l thi gian ng hc. Thi gian ng hc trng tm l h thi gian qun tnh theo nh ngha c hc Newton v cung cp bin thi gian trong cc phng trnh chuyn ng. Thi gian ng hc Tri t qun tnh trc y c gi l thi gian thin vn v dng cho vic phn tch cc phng trnh vi phn vi chuyn ng qu o ca v tinh xung quanh Tri t. Nm 1991, hi thin vn quc t (IAU) a ra thut ng thi gian Tri t (TT) thay th TDT. Hn na thut ng thi gian trong h ta ph hp vi l thuyt tng i tng qut.
Bng 2.2. Cc h thi gian
Qu trnh tun hon
H thi gian
S quay ca Tri t
- Thi gian quc t (UT)
- Thi gian thin vn Greewich (
0
q
)
S xoay vng ca Tri t
- Thi gian ng hc ca Tri t (TDT)
- Thi gian ng hc trng tm (BDT)
Cc giao ng nguyn t
- Thi gian nguyn t quc t (IAT)
- Gi phi hp quc t (UTC)
- Gi GPS (GPST)
Thi gian nguyn t: Thc t h thi gian ng hc c hon tt bng vic s dng t l thi gian nguyn t. H UTC l mt tha hip. n v ca h l giy nguyn t, nhng gia h thi gian gn vi UT1 v thi gian dn dng xp x, giy vi bc nhy nguyn c chen vo cc thi im phn bit. Thi gian GPS cng lin quan vi h thi gian nguyn t. Thi gian GPS c duy tr bi i quan trc Hi qun m (USNO). H thi gian GPS trn danh ngha c lch khng i l 19 giy so vi IAT v trng vi UTC thi k chun 1980 ngy 06 thng 01.
Chuyn i thi gian: S chuyn i gia cc thi gian c suy t s quay ca Tri t (tc l thi gian Mt tri trung bnh c hiu chnh chuyn ng cc UT1 v thi gian thin vn biu kin) c th hin theo cng thc:
ST = 1,0027379093UT1+
e
DY
+
J
cos
.
0
(2.1)
S hng th nht v phi ca cng thc (2.1) do cc t l khc nhau ca thi gian Mt tri v thi gian thin vn, i lng (0 biu din thi gian thin vn thc na m Greewich (tc l 0h UT). S hng th ba miu t s chiu ca ln xch o v ch ti nh hng chng ng. Thi gian thin vn trung bnh suy t cng thc (2.1) bng cch b qua s hng chng ng v l mt phn ca thng tin qung b ti cc v tnh GPS.
Mt chui thi gian c xc nh i vi
0
J
nh sau:
3
0
6
S
2
0
S
0
S
S
0
T
10
.
2
,
6
T
093104
,
0
T
812866
,
8640184
538841
,
24110
-
-
+
+
=
J
(2.2)
trong
0
T
biu th khong thi gian c biu din trong th k Julian 36525 ngy Mt tri trung bnh gia thi k chun J2000.0 v ngy quan st 0hUT
Thi gian UT1 lin quan ti UTC bi i lng dUT1 l s chnh lch v thi gian v c thng bo bi IERS:
1
dUT
UTC
1
UT
+
=
(2.3)
Khi gi tr tuyt i ca
1
dUT
tr nn ln hn 0.9s, mt giy nhy qua c chn vo h UTC.
Thay v bn thn h thi gian ng, h thi gian nguyn t dng nh l thi gian chun trong GPS. Cc mi lin h sau y c xc nh:
000
,
19
GPS
IAT
S
+
=
lch khng i
184
,
32
TDT
IAT
S
-
=
lch khng i
n
UTC
IAT
S
000
,
1
+
=
lch thay i khi cc giy nhy c thay th.
(2.4)
S nguyn thc n c thng bo bi IERS. Vo thng 06/2000, v d: Gi tr nguyn l n = 32, v vy, thi gian GPS chnh lch chnh xc 13 giy so vi UTC ti thi im ny.
Lch: Ngy Julian (JD) xc nh s ngy mt tri trung bnh tri qua t thi im 4713 trc cng nguyn.
Ngy Julian thay i (MJD) thu c bng cch thay 2400000, 5 ngy t JD. Quy c ny gi cc con s v MJD bt u na m ngy dn s thay v bui tra. cho trn vn (bng 2.3) vi ngy Julian i vi hai thi k chun c a ra. V d bng ny cho php tnh ton tham s T i vi thi k chun GPS. Tr ngy Julian tng ng v chia cho 36525 (tc l s ngy trong th k Julian) ta c
1998767967
,
0
T
-
=
Bng 2.3. Cc thi im chun
Ngy dn s
Ngy Julian
Gii thch
0
,
6
d
thng 01-1980
2 444 244,5
Thi im chun GPS
5
,
1
d
thng 01- 2000
2 451 545,0
Thi im chun hin hnh
Chuyn i ngy: Gia s ngy dn s c biu din bng cc gi tr nguyn i vi nm Y, thng M, ngy D v gi tr thc i vi thi gian tnh bng gi UT th:
[
]
[
]
5
,
172098
24
/
UT
D
)
1
m
(
6001
,
30
INT
y
25
,
365
INT
JD
+
+
+
+
+
=
(2.5)
L chuyn i sang ngy Julian khi INT k hiu phn nguyn ca s thc v gi tr (y,m) c cho bi:
y = Y+1 v m = M + 12 nu M 2
y = Y v m = M nu M > 2
(2.6)
Bin i ngc, tc l bin i t ngy Julian thnh ngy dn s, c thc hin kiu bc thang:
[
]
[
]
[
]
[
]
6001
,
30
/
)
d
b
(
INT
e
c
25
,
365
INT
d
25
,
365
/
)
1
,
122
b
(
INT
c
1537
a
b
5
,
0
JD
INT
a
-
=
=
-
=
+
=
+
=
(2.7)
Sau , tham s ngy dn s thu c t cc mi lin h:
[
]
[
]
[
]
(
)
[
]
10
/
M
7
INT
4715
c
Y
14
/
e
INT
121
1
e
M
5
,
0
JD
FRAC
e
6001
,
30
INT
d
b
D
+
-
-
=
-
-
=
+
+
-
-
=
(2.8)
Trong FRAC k hiu phn s ca mt s. Do , ngy ca tun c th c nh gi bng cng thc:
N = modulo
[
]
{
}
7
,
5
,
0
JD
INT
+
(2.9)
Khi N = 0 k hiu ngy th hai, N = 1 ngy th ba, Tnh ton tun GPS theo mi lin h:
(
)
[
]
7
/
5
,
2444244
JD
INT
WEEK
-
=
(2.10)
Cc cng thc ny c th c dng chng thc cc ngy khc nhau hoc kim nghim l thi k J2000.0 tng ng vi ngy th by trong tun GPS th 1042. Ch rng, thi im bt u ca tun th 1024, s tun trong thng tin dn ng c t bng zero v ch c 10 bit c s dng lu tr s tun. Ln thay i u tin xy ra vo gia m 21-22/08/1999.
2.1.2. Qu o v tinh
Cc ng dng ca cng ngh GPS ph thuc ch yu vo vic bit cc qu o v tinh. i vi vic nh v dng my thu n l, sai s qu o tng quan rt cao so vi sai s nh v. Trong trng hp o khong cch ng c s, sai s qu o tng i c xem l xp x bng sai s tng i ca ng c s.
Thng tin qu o c pht ra hoc l bi v tinh nh phn thng tin qung b hoc c th thu c di dng cc lch thin vn chnh xc (c c sau mt vi ngy so vi ngy quan st) t mt s ngun.
2.1.2.1. Miu t qu o
Cc hnh tinh trong h Mt tri chuyn ng trn qu o tun theo ba nh lut do nh ton hc, thin vn hc ngi c Johannes Kepler (1571-1630) xc nh v a ra t u th k 17. Cho n nay, ba nh lut ny vn c p dng biu th quy lut chuyn ng ca cc v tinh nhn to quanh Tri t, gii quyt nhng vn quan trng ca khoa hc v tr.
Ngi ta tha nhn rng hai khi lng im m1 v m2 cch nhau mt khong cch r. Ti mt thi im hy xem xt lc hp dn gia hai khi lng v p dng c hc Newton, chuyn ng ca khi lng m2 so vi m1 c xc nh bi phng trnh vi phn bc hai:
(
)
0
r
r
m
m
G
r
3
2
1
=
+
+
(2.11)
trong
r
l vect v tr tng i, G l hng s hp dn. Thc t, thi gian qun tnh c cung cp bi thi gian ca h thng GPS.
Trong trng hp chuyn ng ca mt v tinh nhn to ca Tri t, trong xp x bc nht, cc khi lng vt th c th c xem nh cc khi lng im v khi lng ca v tinh c th b qua. Tch ca G v khi lng ca tri t ME c k hiu v c bit nh l mt tham s xc nh ca h quy chiu chun WGS-84:
2
3
8
E
s
m
10
.
418
,
3986004
GM
-
=
=
m
(2.12)
Li gii phng trnh vi phn (2.11) c th tm trn cc sch gio khoa v c hc thin th v dn ti chuyn ng Kepler bit c xc nh bi 6 tham s tng ng vi 6 hng s tch phn ca phng trnh vector bc hai. Cc qu o v tinh c th c rt gn li nh l chuyn ng ellip v 6 tham s (
0
T
,
e
,
a
,
,
i
,
w
W
). im gn nht ca v tinh so vi trng tm ca Tri t c gi l im gn nht (cn im) v v tr xa nht c gi l im xa nht (vin im). Giao im gia mt phng xch o v mt phng qu o vi hnh cu n v c gi l cc nt, trong nt i ln xc nh im pha Bc xch o.
2.1.2.2. Thng bo qu o
* Mng li theo di qu o v tinh
Vic xc nh qu o chnh thc ca cc v tinh GPS da trn cc quan st 5 trm theo di thuc khi iu khin. Lch thin vn qung b i vi cc v tinh khi I vi cc ng h cesium c chnh xc khong 5 m. i vi cc v tinh khi II, chnh xc c 1m. Tuy nhin, chnh xc cn thit cho nhng nhim v c bit nh TOPEX/Poseidon hoc i vi cc nghin cu i hi chnh xc c
9
10
-
. Nh vy nhu cu v cc mng li theo di cho vic xc nh qu o l hin nhin.
S v tr cc tiu trong mng li ton cu l 6 nu mt cu hnh nh mong i t nht 2 v tinh c th theo di c mt cch ng thi t ti thi im bt k t hai v tr. Mng li ton cu to ra chnh xc v tin cy ca cc qu o cao hn so vi tin cy xc nh t mng li khu vc. Vic rng buc h thng qu o vi cc h quy chiu chun t c b vic nh v ng thi dng cc my thu GPS vi h theo di VLBI v SLR.
* Mt s mng li ton cu
Ngoi khi iu khin, mt s mng li c thit lp xc nh qu o. Mt s mng li c tnh khu vc hoc lc a nh mng li xc nh qu o GPS ca c.
Thc nghim theo di qu o ton cu u tin c thc hin vo nm 1988 v nhm vo vic s dng ng thi ti liu GPS ti cc v tr trm VLBI v SLR ang tn ti. Ti liu s cho php rng buc chnh xc gia WGS-84 v cc h thng VLBI/SLR. Khong 25 v tr phn b khp ton cu c s dng trong ba tun ca chuyn th nghim ny.
Mng li GPS hp tc quc t (CIGNET) a vo hot ng bi Cc Trc a quc gia M vi cc trm theo di nm v tr cc trm VLBI. Hot ng bt u vo nm 1988 vi 8 trm Bc M, Chu u v Nht Bn. Nm 1991, gn 20 trm phn b trn ton cu tham gia vo. Ba nm sau l hn 30 trm c tch hp vo mng li.
Nm 1990, Hi Trc a quc t quyt nh thnh lp trung tm dch v GPS quc t, sau mt cuc thc nghim kim tra nhng hot ng thng c bt u vo 1/1/1994. Mc ch chnh ca trung tm dch v ny l xc nh qu o cho nhng ng dng a ng lc i hi chnh xc cao. IGS c c quan trung tm phng th nghim phn lc (JPL) M. Nm 1999, mng li theo di qu o da trn hn 220 trm thu GPS phn b khp ton cu (hnh 2.1) vi cc ta v vn tc lin quan ti ITRF. Cc trm IGS thu thp khong cch m ha v pha mang t tt c cc v tinh dng my thu hai tn s. Ti liu ny c phn tch mt cch c lp bi 7 c quan v c lu tr hng ngy di dng trao i c lp vi my thu v phn mm (RINEX) bi cc trung tm s liu khu vc v ton cu. Ngy nay, IGS thng thng cung cp cc qu o c cht lng cao ca tt c cc v tinh. Cc qu o d bo c chnh xc khong 1m sn sng thi gian thc, tri li cc qu o c tnh ton li c a ra sau 2 ngy hoc 2 tun. chnh xc ca li gii cui cng c nh gi l 5 cm. Cc ti liu theo di nguyn thy, cc tham s ng h v tinh, cc tham s nh hng ca Tri t (EOP) v cc ti liu khc nh cc thng tin v tng in ly v i lu lun lun sn sng.
Hnh 2.1. Mng li trm thu GNSS ca trung tm dich v GNSS quc t
2.1.3. nh hng chnh xc ca lch v tinh n kt qu o GPS
Sai s X trong mi thnh phn ca vect cnh c di l v sai s X ca lch v tinh trn h gn ng nhau theo biu thc sau:
)
m
(
X
.
)
m
(
d
)
m
(
l
)
m
(
X
.
d
l
)
m
(
x
D
D
D
(2.13)
trong : d l khong cch gn ng gia v tinh v b mt Tri t.
Bng di y cho chng ta thy sai s ca vect cnh nh v (m) v phn triu vi di vect cnh khc nhau v cht lng v tinh khc nhau c tnh ton theo cng thc gn ng trn.
Bng 2.4. Sai s lch v tinh
Sai s lch v tinh
di vect cnh
Sai s vect cnh (mm)
2.5 m
1 km
2.5 m
10 km
1 mm
2.5 m
100 km
10 mm
2.5 m
1000 km
100 mm
0.05 m
1 km
0.05 m
10 km
0.05 m
100 km
0.2 mm
0.05 m
1000 km
0.2 mm
Trc nm 1992, cht lng ca lch v tinh cn c coi l mt trong cc ngun sai s chnh hn ch chnh xc ca o GPS trong trc a v a ng hc. T khi t chc IGS ra i i vo hot ng, sai s o GPS gy ra bi cht lng ca lch v tinh khng cn ng k. Vi cc sn phm ca IGS cho php xc nh vect cnh ca mng li a ng hc vi chnh xc mc mt vi mm trn khong cch ln. Mt trong cc sn phm quan trng l lch v tinh v thng tin v ng h v tinh vi chnh xc cao. Vi nhiu s phn tch tch th vic s dng lch v tinh chnh xc trong x l d liu GPS chnh xc cao l rt cn thit v quan trng, nht l i vi mng li GPS a ng hc c vect cnh ln t c kt qu tt nht.
2.1.4. Lch v tinh d bo
Mc ch lch v tinh d bo l cung cp cc ti liu vi chnh xc khng cao gip ngi dng d dng tm kim v tinh my thu hoc t cc nhim v nh tnh ton cc bn minh bch. Ti liu nin gim c cp nht t nht trong 6 ngy v c qung b nh mt phn ca thng tin v tinh. Thng tin nin gim ch yu cha cc tham s hiu chnh ng h v tinh, qu o i vi tt c cc v tinh c th hin trong bng 2.5. Tham s l0 biu th s chnh lch gia kinh ca nt thi im t0 v kinh ca nt thi gian thin vn Greenwich t0, thi im bt u ca tun GPS hin hnh.
Bng 2.5. Lch v tinh d bo
Tham s
Gii thch
ID
S v tinh
WEEK
Tun GPS hin hnh
0
t
Thi im chun tnh bng giy trong tun hin hnh
a
Cn bc hai bn trc ln tnh bng m
e
lch tm
0
M
Khong cch gc trung bnh thi im chun
W
S i ln tri dt ca nt i ln trong mi giy
i
d
lch nghing khi 0,3 ln na vng (
0
54
0
l
Kinh ca nt thi im tun
w
Argument ca im cn
0
a
lch ng h v tinh tnh bng giy
1
a
tri ng h v tinh
Lch v tinh d bo c a ln website ca trung tm thng tin khng gian chun (http://www.navcen.uscg.gov/?pageName=gpsAlmanacs) hoc website ca cc phng v b bin M (http://www.navcen.uscg.gov/ftp/GPS/almanac/yuma) di dng YUMA. Di y l mt on trong tp YUMA tun 749 ca v tinh 01.
******** Week 749 almanac for PRN-01 ********
ID: 01
Health: 000
Eccentricity: 0.2616882324E-002
Time of Applicability(s): 503808.0000
Orbital Inclination(rad): 0.9605380230
Rate of Right Ascen(r/s): -0.7714607059E-008
SQRT(A) (m 1/2): 5153.638184
Right Ascen at Week(rad): 0.9331366920E+000
Argument of Perigee(rad): 0.420017871
MeanAnom(rad): 0.3864538025E-002
Af0(s): 0.9822845459E-004
Af1(s/s): 0.3637978807E-011
week: 749
Trong
ID: S hiu v tinh
Health (tnh trng v tinh): 000 = dng c
Eccentricity ( lch tm): Lng lch qu o khi vng trn (qu o). N l khong cch gia tiu im chia cho chiu di ca bn trc ln.
Time of Applicability (thi gian c th p dng): S giy trn qu o khi nin gim c pht ra.
Orbital Incliantion ( nghing qu o): Gc gia qu o v tinh v mt phng xch o (xp x
0
55
i vi v tinh).
Rate of Right Ascension (tc i ln ca nt): Tc thay i ca o gc i ln.
SQRT(A) Square Root of Semi Major Axis (cn bc hai ca bn trc ln): Khong cch tnh t tm qu o ti im xa nht hoc im gn nht.
Argument of Perigee: o gc dc theo qu o c o t nt i ln ti im gn nht, o theo hng chuyn ng ca v tinh.
Mean Anomaly ( lch trung bnh): Gc vt qua kinh tuyn ca nt i ln (gi tr bng 0 180 hoc 0 - m 180 ). Nu gi tr vt qu 180 , ly gi t tr o 360 tm khong cch gc trung bnh. Khi v tinh i qua im gn nht v u hng ti im xa nht, th khong cch gc trung bnh l dng. Sau khi qua im xa nht, khong cch gc trung bnh l m cho ti im gn nht.
Af (0): lch ng h v tinh tnh bng giy
Af (1): tri ca ng h v tinh tnh bng giy trong mi giy.
Vic rt ra cc tham s Kepler i vi thi im quan st t thu c bi cng thc:
)
t
t
(
)
t
t
(
l
l
54
i
)
t
t
(
n
M
M
0
E
0
0
i
0
0
0
-
W
-
-
W
+
=
d
+
=
-
+
=
(2.14)
Trong
11
E
10
.
1467
,
7292115
-
=
W
rad/s l vn tc gc quay ca Tri t. Ba tham s Kepler khc a, e,
w
vn khng thay i. Ch rng trong cng thc (2.14) s hng th hai v phi cha s tu sai ca nt v s hng th ba biu din s thay i ng nht thi gian thin vn t thi k
0
t
. Mt nh gi lch ng h v tinh c cho bi:
)
t
t
(
a
a
0
1
0
s
-
+
=
d
(2.15)
2.1.5. Lch v tinh qung b
Lch qung b, cn c gi l lch pht tn (broadcast ephemeris) hay lch thin vn qung b. Cng vi thng tin o hng, mi v tinh GPS theo chu k pht i lch v tinh qung b ca chnh v tinh .
Cc ti liu theo di qu o b sung c a vo b lc Kalman v cc qu o c hon thin c dng ngoi suy. Trm iu khin chnh chu trch nhim tnh ton lch thin vn v gi ln cc v tinh.
Lch v tinh qung b l mt phn ca thng tin v tinh. V c bn, lch v tinh qung b cha thng tin chung, thng tin qu o, thng tin v ng h v tinh. Cc tham s trong khi thng tin qu o l thi im chun, su tham s miu t Ellip Kepler thi im chun, ba s hng hiu chnh th k v su s hng hiu chnh tnh chu k. Cc s hng hiu chnh tnh ti cc nh hng nhiu lon gy bi tnh khng dng cu ca Tri t, nh hng triu trc tip v p sut bc x Mt tri. Lch v tinh qung b tng gi v s ch c dng trong khong thi gian c miu t xp x 4 ting ng h (bng 2.6) s th hin cc thng tin v lch ny.
Bng 2.6. Lch v tinh qung b
Tham s
Gii thch
ID
S v tinh
WEEK
Tun GPS hin hnh
0
t
Thi im chun ca lch thin vn
a
Cn bc hai bn trc ln
E
lch tm
0
M
lch trung bnh thi im chun
0
w
Argument ca im gn nht
0
i
nghing
0
l
Kinh ca nt thi im tun
n
D
Chnh lch chuyn ng trung bnh
i
Tc ca gc nghing
W
Tc i ln ca nt
uc
C
hoc
us
C
Cc h s hiu chnh (Argunment ca im gn nht)
rc
C
hoc
rs
C
Cc h s hiu chnh ( Khong cch a tm)
ic
C
hoc
is
C
Cc h s hiu chnh ( nghing)
c
t
Thi im chun ca ng h v tinh
0
a
lch ng h v tinh
1
a
tri ca ng h v tinh
2
a
tri tn s ng h v tinh
Hin tng chuyn ng nhiu do hnh dng Tri t khng hon ton trn xoay, do thy triu v do bc x Mt tri.
tnh lch v tinh thi im quan st t, cn cc i lng sau y ngoi cc tham s a v e.
)
u
2
sin(
C
)
u
2
cos(
C
i
i
)
u
2
sin(
C
)
u
2
cos(
C
r
r
)
u
2
sin(
C
)
u
2
cos(
C
)
t
t
(
)
t
t
(
l
l
)
t
t
(
n
a
M
M
ic
ic
0
rc
rc
0
uc
uc
0
0
E
0
0
0
3
0
+
+
=
+
+
=
+
+
w
=
w
-
W
-
-
W
+
=
-
D
+
m
+
=
(2.16)
Trong
v
u
0
+
w
=
l argument v . Khong cch a tm
0
r
c tnh bi phng trnh:
v
cos
e
1
)
e
1
(
a
)
E
cos
e
1
(
a
r
2
0
+
-
=
-
=
vi vic dng a, e, E ti thi im quan st. Ch rng gi khi thng tin cc tham s ng h v tinh cho php tnh ton sai s ng h v tinh ti cc thi im quan st t theo cng thc:
2
c
2
c
1
0
s
)
t
t
(
a
)
t
t
(
a
a
-
+
-
+
=
d
(2.17)
Trong cc cng trnh nghin cu do Remondi v Hofmann Wellenhof (1989), cho thy cc s qu o c chnh xc c 5 m nh cp nht mi ngy ba ln.
My thu nhn c lch v tinh qung b trong thng tin o hng, nh s xc nh tc thi v tr cc v tinh trn qu o (ta X,Y,Z ca v tinh) v tc ca cc v tinh trong h ta WGS-84. Lch v tinh qung b c s dng rng ri trong cc cng tc nh v dn ng, trong cng tc o c thng thng.
* Dng s liu RINEX
RINEX l cc tp s liu o GPS c chun ha di dng ASCII, khng ph thuc vo chng loi my thu. Cc phn mm x l s liu ca cc hng ch to my thu GPS khc nhau u c chc nng chuyn i s liu sang dng RINEX.
Theo quy chun k thut v xy dng li to quc gia (QCVN 04 - 2009 BTNMT) cho chng ta thy tp d liu chun RINEX u c file d liu c th hin di dng xxxx-ddd-s, trong :
- xxxx l 4 ch s cui ca s hiu im.
- ddd l s th t ca ngy trong nm (day of year).
- s l th t ca ca o trong ngy (session number).
Chng hn khi o ti im ta hng III c s hiu im 651442 vo ngy 031 thng 02 tng ng vi ngy th 32 trong nm v l ca o th hai trong ngy tn file s l 14420322.??? trong ??? l phn m rng ca tn file ph thc vo thit b o.
T phin bn 2.10 th s liu o dng RINEX c dng xxxxddds.yyo, xxxxddds.yyn trong :
- xxxxddds c quy nh nh trn.
- yy l hai s cui ca nm (v d i vi nm 2009 yy c gi tr l 09).
- 0 l k hiu i vi file o (observation).
- n l k hiu i vi file lch v tinh (navigation).
Ch rng trong qu trnh chuyn i s liu o gc sang s liu o dng RINEX phi ng thi tin hnh ci chnh cao ngten o thc a v cao thng ng.
Sau y l mt on tp RINEX ca my thu Trimble - R3 nh sau:
Cc tp s liu trn c gii thch nh sau:
Cc tham s i u tp o hng:
(0[giy](1[giy /rad] (2[giy /rad2] (3[giy /rad3]
(0[giy](1[giy /rad] (2[giy /rad2] (3[giy /rad3]
A0[giy]A1[giy / giy]tot[giy] WNt[tun]
(tLS[giy]
Cc tham s i vi tng v tinh:
prn yy mm dd hh mm secaf0[giy] af1[giy / giy] af2[giy / giy 2]
IODE[giy]Crs[m](n[rad/ giy]M0[rad]
Cuc[rad]eCus[rad](A)1/2[m1/2]
toe[giy]Cic[rad](0[rad]Cis[rad]
i0[rad]Crc[m]([rad](dot (
W
&
)[rad/ giy]
idot (
i
&
)[rad/ giy]Code on L2WN[tun]L2 P data flag
SV accuracy[m]SV HealthTGD[giy]IODC[giy]
Thi im pht(s)d phngd phngd phng
2.2. Lch v tinh chnh xc
2.2.1. Qu trnh hnh thnh v pht trin lch v tinh chnh xc
Do tm quan trng ca lch v tinh chnh xc, ngay t nhng nm 1980 cc t chc chuyn mn quc t quan tm, hp tc xc tin vic thit lp lch v tinh chnh xc. Khng nhng vy cc sn phm ny c bn bc, thng nht v tiu chun ho, ngay t u lch v tinh chnh xc c k hiu sp (Standard Product - sn phm tiu chun). Cng nh nhiu sn phm s liu GPS khc (tp Rinex,...), vic tiu chun ho mang li nhiu li ch cho cng ng ngi khai thc s dng. Nm 1982 cc t chc tho thun trin khai thit lp lch v tinh chnh xc. Nm 1985, th h th nht lch v tinh chnh xc c cng b gm sp1 v ECF1, sp2 v ECF2. Lch sp1 dng ASCII, bao gm thnh phn to cng thnh phn vn tc ca v tinh ti thi im nht nh. Khng phi tt c cc ng dng GPS u i hi chnh xc cao, bi vy bn cnh sp1, lch sp2 cng c a vo s dng. Lch sp2 cng dng ASCII, song ch bao gm to ca cc v tinh. Cu trc chi tit ca lch v tinh sp1, sp2 c th tham kho Benjamin W. R. (1985, 1989, 1991). ECF1, ECF2 l dng nh phn tng ng vi sp1 v sp2, EF13 l dng nn ca ECF2.
Nm 1989, cng b th h th 2 ca lch v tinh chnh xc. Ngoi cc thng s nh th h 1, trong tp lch v tinh chnh xc th h 2 cn b xung hiu chnh ng h nhm nng cao chnh xc cc ng dng nh v (positioning). Qu trnh hnh thnh, pht trin v cc c im c bn ca cc dng lch v tinh chnh xc c tng hp bng 2.7. Qu o tiu chun ho mang li nhiu thun li nht l trong chuyn i lch. C hai dng ASCII v nh phn u p ng chc nng ny, song vi dng nh phn n gin hn v dng ny c lp vi h iu hnh ca my tnh.
Bng 2.7. Qu trnh pht trin lch v tinh chnh xc
Thi im
Ni dung
c im
1982
Thng nht ch trng, tng
1985
Cng b th h I
sp1
Dng ASCII, cc thnh phn to v vn tc
ECF1
Dng nh phn, cc thnh phn to v vn tc
sp2
Dng ASCII, cc thnh phn to
ECF2
Dng nh phn, cc thnh phn to
1989
EF13
Dng nn ca ECF2
1989
Cng b th h II
B xung thm hiu chnh ng h, phc v cho cc ng dng nh v chnh xc
sp3
Dng ASCII, cc thnh phn to , vn tc (tu chn), hiu chnh ng h
ECF3
Dng nh phn, cc thnh phn to , vn tc (tu chn), hiu chnh ng h
EF18
Dng nn ca ECF3
1998
sp3b
S liu ca lch sp3 (GPS) kt hp vi lch GLONNAS
2002
sp3c
Dng ASCII, cc thnh phn to , vn tc, hiu chnh ng h v chnh xc cc i lng trn?
C 3 loi:
- Cc thnh phn chnh xc phn u tp, tng thch vi .sp3a v cc phn mm c trc y.
- T ct 62-69: Sai s (standard deviation) v tr
- H s tng quan (correlation) v tr v ng h
Vic cng b lch v tinh chnh xc do IGS iu hnh. S liu quan trc t cc im IGS c chuyn ti cc trung tm sau y x l.
- Jet Propulsion Laboratory (JPL).
- Scripps Institution of Oceanography.
- National Geodetic Survey (NGS).
- GeoForschungsZentrum (Berlin).
- Center for Orbit Determination in Europe (University of Berne, Switzerland).
- European Space Agency.
- Canada (EMR).
Lch v tinh chnh xc cui cng l li gii tng hp ca cc li gii nhn c t cc trung tm.
Lch v tinh chnh xc c xc nh trn c s:
- M hnh chnh xc cho tnh chuyn cc h quy chiu.
- M hnh chnh xc biu din cc nh hng ca cc d thng ti v tinh cng nh im o.
- To chnh xc trong ITRF ca im quan trc v tinh.
- Phn mm x l.
- M hnh sai s tr kh quyn hiu qu.
- M hnh p lc bo Mt tri.
- H thng cc im quan trc lin tc vi quy m ton cu, thu thp s liu vi cht lng cao. Bn cnh cn mt c s tnh ton x l s liu (mang tnh thi gian thc) mnh.
Nhim v ny do cc trung tm quc t nh trn cp m ng. i vi chng ta, nhim v kh thi l thit lp trm o lin tc, p ng c cc chun quc t tham gia vo h thng li v x l s liu ca IGS.
2.2.2. Cu trc ca lch v tinh chnh xc
Mi phn mm x l s liu s dng dng lch v tinh nht nh. Khi x l s liu GPS c s dng lch v tinh chnh xc cn nm vng cu trc, cc i lng cng ngha ca chng. V tng qut, cu trc ca mi loi lch v tinh chnh xc c th chia lm hai phn: phn u tp (header) v phn thn tp. Phn u tp gm cc thng bo tng qut v loi lch, c quan pht hnh, thi gian, loi v tinh,... Phn thn tp l cc i lng lin quan trc tip ti lch v tinh. Tu loi lch m cc i lng v c trng cng nh ngha ca chng c khc nhau. V nguyn tc, cc c quan pht hnh lch v tinh u c thng bo gii thch chi tit cu trc lch. T ngy 29/1/2006, IGS bt u pht hnh lch sp3c (http://www.air-space.us/sci.geo.satellite-nav/16..../), bi vy di y trnh by mt cch chi tit hn v cu trc ca tp lch ny (Hilla, S. 2002b); cc loi lch khc cng c th tm hiu mt cch tng t. bang di y th hin mt on thng tin v lch v tinh chnh xc dng ( *.sp3).
Bng 2.8. Mt phn tp lch *.sp3
Bng 2.9. Cc m t c bn v cu trc tp *.sp3
Hng
M t
1
Phin bn lch (c), loi lch (P: v tr hay V: vn tc), thi gian, s record (192), m t s liu s dung (ORBIT: l hn hp s liu ca nhiu c quan), h to (IGS97), loi qu o (HLM: dng FIT sau khi p dng php bin i Helmert), c quan pht hnh (IGS)
3-7
S hiu v tinh
8-12
chnh xc qu o v tinh c cho di dng lu tha ca c s 2, gi tr = 0: khng xc nh; vi cc gi tr khc c th tnh nh sau: v d vi s m 7, suy ra sai s bng 27 mm = 128mm = 0,128m
13
K hiu cc h v tinh: G l v tinh GPS, R l v tinh GLONNAS, M l v tinh hn hp, E l v tinh Gallileo .
H thi gian: GPS, UTC, ...
15
C s tnh lch chun cho cc thnh phn ca v tr (1,250) cng nh ng h v tinh (1,025).
24
(thn tp)
S hiu v tinh (G01); to X, Y, X (km); sai s ng h (microsec); x-sdev,y-sdev, z-sdev(b**n mm: gi tr b c thng bo hng 15 l 1,25, n = 18 lch chun s l 1,2518~ 56mm); ng h-sdev (tng t s tnh b**n psec: 1.025**219 = 223,1138~223 picoseconds)
Trn y ch l nhng c im quan trng nht c th nhn bit cc i lng, thng s v ngha ca chng trong tp lch. i vi cc ng dng c th cn phi tm hiu mt cch chi tit v hiu su sc t cc ti liu i km ca cc c quan pht hnh lch.
CHNG 3
THC NGHIM
3.1. Li thc nghim
3.1.1. Thi cng li
Li GPS K G - Sng Rc c thit lp nhm xc nh chuyn dch v Tri t khu vc ny. Trn c s nh v tinh, nn a cht, kin to v cc ti liu thc a cng cc nh chuyn mn trc a v tr cc mc c la chn trn bn , vi cc quan im sau:
- y l mt li a phng c quy m nh cc cnh c di xp x 10 km.
- u tin chn mc ti nhng ni c gc nhm m bo loi tr phn ln cc chuyn dch do cc yu t ngoi sinh.
- C thng thong ti a, thun li cho vic thu tn hiu.
- Nm st cc trc ng ln, t di chuyn thun li.
- Khng qu xa v qu gn khu dn c, m bo cc iu kin hu cn, an ninh khi do c.
- u tin ni c ph sng di ng, thun tin cho vic lin lc trong cc ca o.
Qu trnh kho st thc a v thi cng li trn c s cc ti liu c tin hnh vo thng 5 nm 2005.
S lng im o GPS v v tr ca chng c cn nhc, chn la k cng ngoi thc a, vi s tham gia ca cc nh kin to cng nh cc nh trc a, nhm p ng ti a yu cu nghin cu chuyn dch khu vc ny bng cng ngh GPS. Tt c cc du mc u c lm bng vt liu khng g (inox), c ngy trang k m bo tn ti lu di. thng thong c m bo. Bn cnh , trong iu kin c th cc mc c chn khng xa khu dn c to iu kin thun li cho cng tc o c, an ton lao ng v an ninh.
Li GPS K G - Sng Rc gm 4 im:
- im RUH1 nm ngha trang lit s th trn Cm Xuyn, huyn Cm Xuyn, H Tnh.
- im XCB1 nm ng t ch nh, x Cm Bnh, huyn Cm Xuyn, H Tnh.
- im DKG2 ti p trn dc Miu, h K G, x Cm M, huyn Cm Xuyn, H Tnh.
- im NAH1 nm x Nam Hng, huyn Thch H, H Tnh.
V c bn li c thit k vi hnh hp l, p ng c cc yu cu k thut t ra. Cc mc u c thi cng cn thn, thun li cho vic nh tm cng nh tin hnh o c.
3.1.2 o li
Li GPS c o vao thng 7/2005. Quy trnh o cho li GPS K G - Sng Rc c son tho, hng dn thc hin cc cng vic o c ti mi im nh: nh tm chnh xc anten, hng anten v phng Bc, o cao anten, kim tra hot ng ca my trong qu trnh thu tn hiu,... Thit b o l b ba my thu hai tn s Trimble 4000SSi cng anten hai tn s Compact L1/L2 vi a chng nhiu x tn hiu. S lng v di ca o c quyt nh trn c s cc kho st cng nh kinh nghim v di ca o, chiu di c th cc cnh li GPS, iu kin vt cht, k thut hin c c tin hnh 6 ca o (Bng 3.1), vi thi lng mi ca 9 gi. Ca o bt u vo 8 gi sng v kt thc vo 17 gi ti. y l qung thi gian m ti tt c cc im li cc yu t o c u tt, s lng v tinh t 4 tr ln, suy gim PDOP t di 5.
Phng php o tnh c p dng vi cc tham s hot ng ca my thu: Gc ngng cao thu tn hiu l 10(, tn sut ghi tn hiu l 15 giy v s lng v tinh ti thiu l 1. S lng o t nht 3 ca ti mi im khng ch m bo an ton t o, lm tng cc tr o tha v do lm tng chnh xc cc kt qu o GPS.
Bng 3.1. Tng hp cc tp s liu o
STT
DOY
Cc tp o
1
155
XCB2
RUH1
DKG1
2
156
XCB2
RUH1
DKG1
3
157
NAH1
RUH1
DKG1
4
158
NAH1
RUH1
DKG1
5
159
NAH1
XCB2
DKG1
6
160
NAH1
XCB2
DKG1
3.2. X ly s liu
3.2.1. Ni dung cng vic v cc bc thc hin
- Khai thc d liu lch v tinh chnh xc t t chc IGS
- Tnh ton bnh sai cc im NAH1, XCB2, DKG1, RUH1 da vo cc tp lch v tinh qung b, tp lch v tinh chnh xc.
- nh gi kt qu s l t c da vo lch v tinh qung b v lch v tinh chnh xc.
* i vi lch v tinh qung b tin hnh tnh ton theo cc bc sau:
Bc 1: a d liu t tp lch v tinh qung b vo trong li gii cnh.
Bc 2: Xy dng li t cc gi tr cnh nhn c sau khi tnh khi lc.
Bc 3: Bnh sai mng li t do trn h ta WGS-84 ton cu (khng c im khi tnh).
Bc 4: S dng m hnh Geoid EGM-2008(1x1) xc nh cao Geoid N cho tt c cc im trong li so vi mt Ellipsoid WGS-84.
Bc 5: Bnh sai s b mng li pht hin v loi b cc sai s th (ch yu l do nhm mc).
Bc 6: Bnh sai chnh thc mng li, xut d liu sang tp vn bn.
Kt qu tnh ton lch v tinh qung b c trnh by trong ph lc 1.
* i vi lch v tinh chnh xc tin hnh tnh ton theo cc bc sau:
Bc 1: Xy dng li t cc gi tr cnh nhn c sau khi tnh khi lc.
Bc 2: Bnh sai mng li t do trn h ta WGS-84 ton cu (khng c im khi tnh).
Bc 3: S dng m hnh Geoid EGM-2008(1x1) xc nh cao Geoid N cho tt c cc im trong li so vi mt Ellipsoid WGS-84.
Bc 4: a d liu t tp lch v tinh chnh xc vo trong li gii cnh.
Bc 5: Bnh sai s b mng li pht hin v loi b cc sai s th (ch yu l do nhm mc).
Bc 6: Bnh sai chnh thc mng li, xut d liu sang tp vn bn.
Kt qu tnh ton lch v tinh qung b c trnh by trong ph lc 2.
3.2.2. Qu trnh x l
tin hnh x l mng li ti khu vc K G - Sng Rc ti H Tnh s dng phn mm Trimble Business Center 2.0. tnh ton v so snh c cc kt qu nhn c em coi cc tham s ci t nh nhau, tnh ton mt cch hon ton ging nhau ch c thay i lch v tinh.
hnh thc nghim (chiu di cnh di nht Smax = 15363.761 m l cnh RUH1 - NAH1, cnh c chiu di ngn nht Smin = 6308.906 m l cnh RUH1- XCB2, chiu di trung bnh 10971.015 m) trong hnh 3.1.
Hnh 3.1: hnh thc nghim o GPS
3.3. Kt qua thc nghim
Bng vic s dng Modul bnh sai, v chy cnh trng b phn mm Trimble Business Center 2.0 tin hnh x l cc cnh (baseline) trong mng li, kt qu nh gi cht lng s dng lch v tinh chnh xc so vi lch v tinh c th hin cc bng sau y:
Bng 3.2. nh gi chnh xc v cc ch tiu
Ni dung nh gi
Lch v tinh chnh xc
Lch v tinh qung b
1. Sai s RMS
- Ln nht (DKG1_XCB2)
- Nh nht (NAH1_XCB2)
0.019
0.006
0.019
0.006
2. T s Ratio
- Nh nht (DKG1_XCB2)
- Ln nht (RUH1_XCB2)
2.010
17.312
2.012
17.362
3. Sai s khp tam gic
- Ln nht
- Nh nht (RUH1_XCB2_DKG1)
1/1502843
1/4743159
1/1537494
1/3041216
4. Sai s khp chnh cao tam gic
- Nh nht (NAH1_XCB2_DKG1)
- Ln nht (RUH1_XCB2_NAH1)
-0.003 m
- 0.019 m
0.002 m
-0.017 m
5. Sai s o phng v
- Ln nht (RUH1_XCB2)
- Nh nht (RUH1_NAH1)
0.11"
0.05"
0.14"
0.06"
6. Sai s v tr im
- Nh nht (DKG1)
- Ln nht (NAH1)
0.003 m
0.004 m
0.003 m
0.004 m
8. Sai s chnh cao
- Nh nht (XCB2_DKG1)
- Ln nht (RUH1_NAH1)
0.033 m
0.041 m
0.041 m
0.051 m
9. Sai s tng i cnh
- Nh nht (XCB2_DKG1)
- Ln nht (RUH1_XCB2)
1/4174260
1/1814424
1/3280929
1/1430279
Bng 3.3. lch ta vung gc khng gian sau bnh sai
STT
S hiu im
X (m)
Y (m)
Z (m)
1
DKG1
-0.3263
1.1432
0.3913
2
NAH1
-0.3193
1.123
0.3854
3
RUH1
-0.3213
1.1203
0.3846
4
XCB2
-0.3362
1.1755
0.4041
tin hnh nh gi vic s dng lch v tinh cn tnh gi tr chnh lch sai s trung phng theo cc trc (x,y) v sai s trung phng v tr im. lch trung phng ta v v tr gia cc im trong qu trnh s dng lch v tinh chnh xc v lch v tinh qung b nh bng 3.4.
Bng 3.4. chnh lch sai s trung phng v tr gia cc im
STT
Tn im
mx (m)
my (m)
mp (m)
1
DKG1
0
0
0
2
NAH1
-0.001
0
0
3
RUH1
-0.001
-0.001
-0.001
4
XCB2
0
-0.001
-0.001
KT LUN VA KIN NGHI
* Kt lun
T qu trnh nghin cu thc hin n em c mt s kt lun nh sau:
1. Lch v tinh chnh xc l mt trong nhng yu t hng u trong vic t c chnh xc, xc nh cc thnh phn ca vect baseline mc mm, lch v tinh chnh xc c tnh trong ITRF- yy do t chc quc t IGS cung cp.
2. Qua qu trnh s dng phn mm Business Center 2.0 tnh ton s liu li GPS K G - Sng Rc ti tnh H Tnh vi bn im NAH1, XCB1, DKG2, RUH1 cho thy:
- Kt qua binh sai khi tnh chuyn v h ta phng khi s dung lch v tinh chnh xc va lch v tinh qung b khong cch ngn di 15 km la nh nhau.
- chinh xac sau binh sai cua li khi s dung lich v tinh chinh xac tt hn khi khng s dung lich v tinh chinh xac khi binh sai li.
* Kin nghi
Trn c s kt qua a at c, em co kin nghi o la cn tip tuc nghin cu, tinh toan, khao sat thy c vai tro cua lich v tinh chinh xac trong vic x ly s liu GNSS i vi cac li co khoang cach ln hn.
DANH MC TI LIU THAM KHO
[1] ng Nam Chinh, Ngc ng, Bi ging cng ngh GPS, H Ni thng 01 nm 2007.
[2] ng Nam Chinh, Ngc ng, nh v v tinh GPS, H Ni thng 05 nm 2012.
[3] Vy Quc Hi, Kim tra cht lng s liu GPS. Tp ch cc khoa hc v Tri t 2/2006, tr.287-292, H Ni.
[4] Vy Quc Hi (2004), So snh kt qu x l s liu GPS ca li a ng lc bng phn mm GPSurvey 2.35 v Bernese 4.2, Tp ch Cc khoa hc v Tri t.
[5] Vy Quoc Hai, Tran inh To, Vu Tuan Hung (2006), Present crustal movements of the fault zones at Son La area derived from GPS 2001-2005 measurment data. Colloque International: Application de la tldtection, des SIG et des GPS pour la rduction des risques naturels et le dveloppement durable. Hanoi - Vietnam, 11-14 Mars 2006.
[6] Vy Quc Hi, Kang Joon Mook (2001), Some results of examination on duration of measuring session by the Static GPS method. Journal of Geology, series B, No 17-18/2001, pp.111-120, H Ni.
Ph lc 1. Kt qu bnh sai s dung lch v tinh qung b
Bng 1: Tr o gia s ta v cc ch tiu sai s
H ta vung gc khng gian Ellipsoid quy chiu: WGS-84
Ln o
im u
im cui
DX
DY
DZ
DH
RMS
Ratio
1550
RUH1
XCB2
4385.369
-333.019
4523.358
-31.232
0.007
14.317
1560
RUH1
XCB2
4385.364
-333.005
4523.357
-31.218
0.011
11.193
1600
NAH1
XCB2
-10442.599
-4287.039
3786.996
-8.779
0.006
16.948
1560
DKG1
XCB2
-3382.233
-4587.686
10437.888
-37.460
0.016
2.012
1560
DKG1
RUH1
-7767.601
-4254.672
5914.522
-6.236
0.013
3.503
1570
DKG1
RUH1
-7767.596
-4254.672
5914.532
-6.235
0.011
2.803
1580
DKG1
RUH1
-7767.593
-4254.686
5914.531
-6.248
0.007
5.398
1550
DKG1
XCB2
-3382.227
-4587.693
10437.889
-37.468
0.011
2.583
1550
DKG1
RUH1
-7767.596
-4254.679
5914.520
-6.244
0.011
4.063
1580
DKG1
NAH1
7060.368
-300.651
6650.912
-28.679
0.008
13.801
1580
NAH1
RUH1
-14827.971
-3954.032
-736.380
22.436
0.007
5.492
1590
NAH1
XCB2
-10442.601
-4287.014
3786.996
-8.755
0.011
5.145
1590
DKG1
NAH1
7060.359
-300.639
6650.912
-28.666
0.017
5.076
1590
DKG1
XCB2
-3382.231
-4587.657
10437.907
-37.428
0.019
2.085
1600
DKG1
NAH1
7060.364
-300.640
6650.907
-28.670
0.011
3.806
1600
DKG1
XCB2
-3382.231
-4587.692
10437.904
-37.462
0.010
4.629
1570
DKG1
NAH1
7060.366
-300.644
6650.912
-28.673
0.012
4.753
1570
NAH1
RUH1
-14827.974
-3954.013
-736.377
22.456
0.009
4.831
3130
XCB2
NAH1
10442.520
4287.290
-3786.903
9.058
0.009
6.878
3130
DKG1
NAH1
7060.351
-300.594
6650.927
-28.618
0.010
6.174
3130
DKG1
XCB2
-3382.167
-4587.864
10437.838
-37.656
0.012
3.186
3120
DKG1
XCB2
-3382.230
-4587.667
10437.905
-37.439
0.009
5.682
3160
XCB2
NAH1
10442.583
4287.031
-3786.989
8.778
0.012
6.466
3110
DKG1
RUH1
-7767.607
-4254.667
5914.539
-6.224
0.017
10.265
3140
DKG1
NAH1
7060.357
-300.615
6650.910
-28.644
0.014
7.459
3150
DKG1
NAH1
7060.307
-300.422
6650.963
-28.438
0.016
5.919
3150
NAH1
RUH1
-14827.972
-3954.021
-736.382
22.447
0.014
4.727
3110
RUH1
XCB2
4385.378
-333.028
4523.358
-31.243
0.010
15.024
3110
DKG1
XCB2
-3382.233
-4587.674
10437.915
-37.441
0.016
4.883
3160
DKG1
NAH1
7060.361
-300.623
6650.915
-28.651
0.018
14.768
3160
DKG1
XCB2
-3382.221
-4587.662
10437.909
-37.435
0.019
5.343
3140
RUH1
NAH1
14827.972
3954.013
736.371
-22.458
0.010
17.192
3140
DKG1
RUH1
-7767.620
-4254.618
5914.542
-6.175
0.015
6.277
3120
RUH1
XCB2
4385.448
-333.273
4523.275
-31.510
0.008
17.362
3120
DKG1
RUH1
-7767.684
-4254.399
5914.624
-5.933
0.007
16.367
- RMS ln nht:
RMS = 0.019
(DKG1_XCB2)
- RMS nh nht:
RMS = 0.006
(NAH1_XCB2)
- Ratio ln nht:
Ratio = 17.362
(RUH1_XCB2)
- Ratio nh nht:
Ratio = 2.012
(DKG1_XCB2)
Bng 2: Sai s khp hnh
H ta vung gc khng gian Ellipsoid quychiu: WGS-84
S hiu vng khp
dX(m)
dY(m)
dZ(m)
dh(m)
dXYZ
[S](m)
dXYZ/[S]
RUH1_XCB2_NAH1
-0.003
-0.012
-0.018
-0.017
0.022
33579.4
1/1537494
RUH1_XCB2_DKG1
0.000
-0.005
-0.008
-0.008
0.009
28851.5
1/3041216
NAH1_XCB2_DKG1
0.002
-0.004
0.020
0.002
0.020
33503.6
1/1634810
RUH1_DKG1_NAH1
-0.002
-0.011
0.010
-0.007
0.015
35717.9
1/2381196
Tng s tam gic: 4
- Sai s khp tng i tam gic ln nht:
1/1537494
[S]=33579.4m
(RUH1_XCB2_NAH1)
- Sai s khp tng i tam gic nh nht:
1/3041216
[S]=28851.5m
(RUH1_XCB2_DKG1)
- Sai s khp chnh cao tam gic nh nht:
0.002m
[S]=33503.6m
(NAH1_XCB2_DKG1)
- Sai s khp chnh cao tam gic ln nht:
-0.017m
[S]=33579.4m
(RUH1_XCB2_NAH1)
Bng 3-1: Tr o, s hiu chnh v tr bnh sai gc phng v
H ta trc a Ellipsoid quychiu: WGS-84
TT
K hiu gc
Tr o
( o ' ")
Sai s o
(")
S hiu chnh
(")
Tr bnh sai
( o ' ")
im u
im cui
1
RUH1
XCB2
319 11 01.00
0.14
0.03
319 11 01.03
2
DKG1
NAH1
316 16 41.00
0.08
0.32
316 16 41.32
3
RUH1
XCB2
319 11 01.00
0.14
0.05
319 11 01.05
4
XCB2
NAH1
250 25 51.00
0.08
0.00
250 25 51.01
5
DKG1
XCB2
22 17 23.00
0.07
0.05
22 17 23.05
6
DKG1
XCB2
22 17 23.00
0.07
0.16
22 17 23.16
7
DKG1
XCB2
22 17 23.00
0.07
0.23
22 17 23.23
8
XCB2
NAH1
250 25 51.00
0.08
0.03
250 25 51.03
9
DKG1
RUH1
54 11 24.00
0.08
-0.17
54 11 23.83
10
DKG1
RUH1
54 11 24.00
0.08
0.01
54 11 24.01
11
NAH1
XCB2
70 23 51.00
0.08
-0.04
70 23 50.96
12
DKG1
XCB2
22 17 23.00
0.07
-0.15
22 17 22.85
13
DKG1
RUH1
54 11 24.00
0.08
-0.15
54 11 23.85
14
DKG1
XCB2
22 17 23.00
0.07
-0.04
22 17 22.96
15
NAH1
RUH1
92 53 53.00
0.06
-0.11
92 53 52.89
16
RUH1
XCB2
319 11 01.00
0.14
-0.04
319 11 00.96
17
DKG1
NAH1
316 16 41.00
0.08
-0.12
316 16 40.88
18
DKG1
NAH1
316 16 41.00
0.08
-0.12
316 16 40.88
19
NAH1
XCB2
70 23 51.00
0.08
0.05
70 23 51.05
20
DKG1
XCB2
22 17 23.00
0.07
0.07
22 17 23.07
21
DKG1
RUH1
54 11 24.00
0.08
-0.11
54 11 23.89
22
DKG1
NAH1
316 16 41.00
0.08
0.08
316 16 41.08
23
DKG1
XCB2
22 17 23.00
0.07
0.05
22 17 23.05
24
RUH1
XCB2
319 11 01.00
0.14
0.04
319 11 01.04
25
DKG1
NAH1
316 16 41.00
0.08
-0.07
316 16 40.93
26
NAH1
RUH1
92 53 53.00
0.06
-0.09
92 53 52.91
27
DKG1
RUH1
54 11 24.00
0.08
0.11
54 11 24.11
28
DKG1
RUH1
54 11 24.00
0.08
0.06
54 11 24.06
29
DKG1
XCB2
22 17 23.00
0.07
-0.07
22 17 22.93
30
NAH1
RUH1
92 53 53.00
0.06
-0.04
92 53 52.96
31
DKG1
NAH1
316 16 41.00
0.08
0.00
316 16 41.01
32
DKG1
RUH1
54 11 24.00
0.08
-0.08
54 11 23.92
33
DKG1
NAH1
316 16 41.00
0.08
-0.06
316 16 40.95
34
DKG1
NAH1
316 16 41.00
0.08
-0.01
316 16 40.99
35
RUH1
NAH1
272 56 37.00
0.06
-0.01
272 56 36.99
- Sai s o phng v ln nht:
mamax =
0.14"
(RUH1_XCB2)
- Sai s o phng v nh nht:
mamin =
0.06"
(NAH1_RUH1)
- S hiu chnh phng v ln nht:
damax =
0.32"
(DKG1_NAH1)
- S hiu chnh phng v nh nht:
damin =
0.00"
(XCB2_NAH1)
Bng 3-2: Tr o, s hiu chnh v tr bnh sai cnh
H ta trc a Ellipsoid quychiu: WGS-84
TT
K hiu cnh
Tr o
(m)