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FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 1
GNSS HEIGHTING AND ITS
POTENTIAL USE IN MALAYSIA
DEPARTMENT OF SURVEY AND MAPPING
MALAYSIA
Hasan Jamil
FIG WORKING WEEKMarrakech WW2011
PRESENTATION OUTLINE
Vertical datum and Levelling Background
Case Studies
Conclusion
GNSS Heighting
Introduction
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 2
BRIEF: Malaysia - Morocco
MAP OF MALAYSIA
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 3
MALAYSIA
Land Area: 329,758 square km
Population: 28 million
Climate: Tropical, temperature
from 23 oC - 32 oC
Maritime Area: 603,210 square km
Location: South East Asia
BACKGROUND
Horizontal and verticalcontrol in Malaysia fallsunder Department of Surveyand Mapping
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 4
VERTICAL DATUM AND
LEVELLING IN MALAYSIA
1908 : Earliest Vertical Datum at Port
Klang
1912 : First National Vertical Datum
(LSD)
1967 : First Order Levelling Network
(FOLN67)
1912 : First line levelled from Port Klang
to Kuala Lumpur
VERTICAL DATUM AND
LEVELLING IN MALAYSIA
1984-1993 : Peninsular Malaysia Geodetic
Vertical Datum (10-year tidalobservation)
1985-1999 : Precise Levelling Network
2000 onwards : Upgrading of Precise LevellingNetwork
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 5
PRECISE LEVELLING NETWORK
THAILANDGETING
CHENDERING
TG.GELANG
PULAU
TIOMAN
SEDILI
JOHOR
BAHRU
TG.KELING
PORTKLANG
LUMUT
PULAU
PINANG
PULAU
LANGKAWI
KUALA
LUMPUR
SINGAPORE
KANGAR
NAKA
PADANG
BESARBUKIT
KAYU
HITAM
SIK
ALOR
SETAR
GURUN
BALING
BUTTERWORTH
KG.SUMPITA
N
GERIK
IPOH
BAGAN
SERAI
AYER
TAWAR
SITIAWAN
BEHRANG
SG.BESAR
BENTA
TRANUM
KUALA
KUBU
BENTONG
KARAK
JERANTUT
TEMERLOH
KG.AWAHGAMBANG
KUANTAN
KOTA
BHARU
BANDING
MUADZAM
KERATONG
LEBAN
CHONDON
G
SEGAMAT
AYER KEROH
MELAKA
PEDAS
LINGGI
SEREMBAN
BAHAU
SERTINGKELANG
AYER
HITAM
BATU PAHAT SKUDAI
PONTIAN
KECIL
JEMALUANG
GUA
MUSANG
TIDE GAUGE STATION
LEVELLING NETWORK
JUNCTION POINT
Extent of Precise Levelling Network in Peninsular Malaysia
Conventional Digital (bar coded)Motorised
Methods Of Survey
PRECISE LEVELLING NETWORK (contd.)
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 6
Uses spirit levelling in determination
of orthometric height
Simple and effective but slow
PRECISE LEVELLING NETWORK (contd.)
MALAYSIA GEOID MODEL
Malaysia has established its geoid model
which is known as MyGEOID in 2004 and 2005
Peninsular Malaysia : WMGEOID04
Sarawak and Sabah : EMGEOID05
Peninsular Malaysia
Sabah
Sarawak
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 7
The range of geoidal height value is between -16 m (northern area) to 10 m (southern area)
99 100 101 102 103 104 105
LONGITUDE
PENINSULAR MALAYSIA GEOID
1
2
3
4
5
6
7LATIT
UDE
-24
-22
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
SOUTH CHINA SEA
STRAIT
S O
F M
ALACCA
SCALE BAR ( METER )
PENINSULAR MALAYSIA :
WMGEOID04
MyRTKnet
99.50 100.00 100.50 101.00 101.50 102.00 102.50 103.00 103.50 104.00 104.50
Longitude
ARAU
BABH
BANT
BEHR
GETI
GMUS
GRIK
JHJY
JUML
KLAW
KUAL
KUKP
LGKW
MERS
MERU
PEKN
PUPK
SGPT
TGPG
TLOH
UPMS
USMP
UUMK
AYER
BAHA
BENT
CAME
CENE
GAJA
JRNT
KRAI
KROM
LASA
LIPI
MUAD
MUKH
PASP
PDIC
PRTS
PUSI
SBKB
SEG1
SETI
SIK1
SPGR
SRIJ
TERI
TGRH
TLKI
TOKA
Sabah and Sarawak - 28 stations
110 111 112 113 114 115 116 117 118 119
Longitude (E)
1
2
3
4
5
6
7
La
titu
de
(N
)
UMAS
AMAN
SIBU
BINT
MIRI
LAB1
UMSS
SAND
TAWA
SEMA
KAPI
BEAUKENI
KUDA
TENO
JAMB
TUNKLAHA
SEMP
RANA
KBEL
TEBE
MUKA BELA
MARU
LIMBLAWA
LSEM
MRDU
NIAH
SRTK
RANA
Malaysia has established Malaysia Real-time Kinematic
GNSS Network (MyRTKnet) in 2006 - 2009
Peninsular Malaysia - 50 stations
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 8
GNSS HEIGHTING
Relationship between orthometric height, geoid and ellipsoid
H = h - N
H = Height above geoid (GPS derived orthometric height)
h = Height above ellipsoid (GPS height)
N = geoid-ellipsoid separation, geoid height from gravimetric geoid model (geoidal height)
where:
FLOWCHART OF GNSS HEIGHTING
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 9
Field Procedure
No. Items Parameter
1. Observation
Technique
Static positioning
2. GNSS Control At least 3 stations
3. Observation
Sessions
At least 2 independent sessions
4. Station Connections At least 3 independent baselines
5. VDOP Less than 6 (90% of the
observation session)
6. Elevation Angle Above 10°
7. Satellite Tracking At least 5 satellites with GDOP of
less than 6
8. Equipment
Calibration
As regulated
9. MyRTKnet Usage As regulated
GNSS-DERIVED ORTHOMETRIC HEIGHT -
Recommended Guidelines
Office ProcedureNo. Items Parameter1. General Procedure Prescribed procedures as provided in
manufacturer manual must be followed.2. Datum GDM20003. Ephemerides Short baselines of less than 30 km: Broadcast.
Long baselines: precise.4. Baseline Processing
QualityRMS less than 2 cm.Maximum data rejection - less than 10 %.Ambiguity fixed solution.Aposteriori variance factor is unity.
5. Adjustment Only independent baselines (n-1) should be included in the adjustment.Least square adjustment should be used.
6. Minimally ConstrainedAdjustment
1 control station fixed in GDM2000 coordinates.
7. Quality Indicator Pass Chi-squares test at 95% confident region.All baselines must pass the local test.
8. Test on Control Stations
Relative precision must be less than 2 ppm (2D) and 3 ppm on the vertical component.
9. Over-constrainedAdjustment
At least 2 control stations must be fixed in the final adjustment.
Note: The office procedures are carried out using Trimble Geomatic Office (TGO) software
Recommended Guidelines (contd.)
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 10
CASE STUDIES
Method - either RTK or static technique on BMs
GNSS observation in progress
Results - horizontal positions (lat & long) and verticalpositions (ellipsoidal height)
Compare to the levelling height
CASE STUDY 1
Penang Bridge
GNSS observations with static technique
involving a total number of 3 bench marks (BM)
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 11
RESULTS - CASE STUDY 1
Difference Between GNSS Heighting & Levelling
(cm)
No. of Observation
< 1 3
Peninsular Malaysia
CASE STUDIY 2
GNSS observations with RTK technique involving
a total number of 77 bench marks (BM)
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 12
RESULTS - CASE STUDY 2
Difference Between GNSS Heighting & Levelling
(cm)
No. of Observation &
(%)
< 10 59
(77 %)
10 – 18.8 18
(23%)
BMs observed in Pahang
BMs observed in Johor
BMs observed in Melaka
BMs observed in Selangor
SBMs
BMs observed in Kedah
BMs observed in Perak
BMs observed in Kelantan
BMs observed in Negeri Sembilan
BMs observed in Terenganu
BMs observed in Perlis
0.00 m
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
0.25
0.3
Total Points Observed
Dif
fere
nt
in m
ete
r
Scatter plot of the difference between Orthometric
Heights Derived GNSS and Levelling
RESULTS - CASE STUDY 2 (contd.)
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 13
Tanjung Malim, Perak
CASE STUDY 3
GNSS observations with static technique involving a total number of 11 bench marks (BM)
RESULTS - CASE STUDY 3
Difference Between GNSS Heighting & Levelling
(cm)
No. of Observation &
(%)
< 10 7
(64 %)
10 – 16.2 4
(36%)
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 14
RESULTS - CASE STUDY 3 (contd.)
Scatter plot of the difference between Orthometric Heights Derived GNSS and Levelling
CONCLUSION
The development of geodetic
infrastructures such as MyRTKnet and
MyGEOID has given great opportunity inenhancing the determination of heightingusing GNSS.
The conventional spirit levelling requires alot of time and is a costly operation as wellas involves a lot of manpower as
compared to GNSS heighting.
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 15
CONCLUSION
Based on the initial studies that have been
carried out, the results indicate that the
accuracy achievable by GNSS heighting in
Malaysia can provide second order
levelling standard.
However, more case studies need to be
conducted regarding GNSS heighting.
Look Forward To Meeting You In
Kuala Lumpur In June 2011 and 2014
22 – 24 June 2011
PUTRA WORLD TRADE CENTRE
Kuala Lumpur, Malaysia
www.seasc2011.org
FIG Working Week 2011
Bridging the Gap between Cultures
Marrakech, Morocco, 18‐22 May 2011 16
Look Forward To Meeting You In
Kuala Lumpur In June 2011 and 2014
Thank you for your attention ....Thank you for your attention ....Thank you for your attention ....Thank you for your attention ....