FIG WORKING WEEK Marrakech WW2011

GNSS HEIGHTING AND ITS POTENTIAL USE IN

Hasan Jamil DEPARTMENT OF SURVEY AND MAPPING MALAYSIA

PRESENTATION OUTLINE

Introduction Vertical datum and Levelling Background GNSS Heighting Case Studies

Conclusion

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 1 BRIEF: Malaysia - Morocco

MAP OF MALAYSIA

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 2 MALAYSIA

Location: South East Asia Land Area: 329,758 square km Maritime Area: 603,210 square km Population: 28 million Climate: Tropical, temperature from 23 oC - 32 oC

BACKGROUND

Horizontal and vertical control in Malaysia falls under Department of Survey and Mapping

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 3 VERTICAL DATUM AND LEVELLING IN MALAYSIA

1908 : Earliest Vertical Datum at Port Klang

1912 : First National Vertical Datum (LSD) 1912 : First line levelled from Port Klang to 1967 : First Order Levelling Network (FOLN67)

VERTICAL DATUM AND LEVELLING IN MALAYSIA

1984-1993 : Geodetic Vertical Datum (10-year tidal observation)

1985-1999 : Precise Levelling Network

2000 onwards : Upgrading of Precise Levelling Network

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 4 PRECISE LEVELLING NETWORK

PADANG BESARBUKIT KAYU KANGARHITAM NAKA THAILAND GETING KOTA PULAU BHARU GURUN SIK

BALING CHENDERING BANDING PULAU BUTTERWORTH PINANG KG.SUMPITA N GUA BAGAN MUSANG SERAI

IPOH

AYER BENTA TAWAR JERANTUT SITIAWAN LUMUT BEHRANG TG.GELANG TRANUM SG.BESAR KUANTAN BENTONG KG.AWAH KUALA GAMBANG KUBU TEMERLOH KARAK KUALA MUADZAM LEBAN PORT LUMPUR CHONDON PULAU KLANG KELANG G TIOMAN SEREMBAN SERTING KERATONG

BAHAU PEDAS SEGAMAT LINGGI AYER KEROH JEMALUANG MELAKA TG.KELING TIDE GAUGE STATION AYER SEDILI HITAM

LEVELLING NETWORK JOHOR BATU PAHAT SKUDAI BAHRU PONTIAN JUNCTION POINT KECIL SINGAPORE

Extent of Precise Levelling Network in Peninsular Malaysia

PRECISE LEVELLING NETWORK (contd.)

Methods Of Survey

ConventionalMotorised Digital (bar coded)

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 5 PRECISE LEVELLING NETWORK (contd.)

Uses spirit levelling in determination of orthometric height

Simple and effective but slow

MALAYSIA GEOID MODEL

Malaysia has established its geoid model which is known as MyGEOID in 2004 and 2005

Sabah

Peninsular Malaysia

Sarawak

Peninsular Malaysia : WMGEOID04 Sarawak and Sabah : EMGEOID05

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 6 PENINSULAR MALAYSIA : WMGEOID04

PENINSULAR MALAYSIA GEOID SCALE BAR ( METER ) 7 12 10

6 8 6 4 SOUTH CHINA SEA 5 2 0 -2 -4 4 -6

LATITUDE -8 S T R A IT -10 S O 3 F M -12 A L A C C A -14 -16 2 -18 -20 -22 1 -24 99 100 101 102 103 104 105 LONGITUDE The range of geoidal height value is between -16 m (northern area) to 10 m (southern area)

MyRTKnet

Malaysia has established Malaysia Real-time Kinematic GNSS Network (MyRTKnet) in 2006 - 2009

Peninsular Malaysia - 50 stations Sabah and Sarawak - 28 stations

ARAU UUMK LGKW GETI

TOKA

SIK1 PASP AYER SGPT KRAI SETI GRIK USMP KUAL 7 KUDA BABH TERI MRD LASA KBE L JAMB GMUS UMSS U RANA 6 MUKH SAND PUSI RANA CAME BEAU LAB1 KENI PUPK LIPI TENO CENE LAHA TUNK TLKI 5 LIMB LAWA JRNT SBKB BEHR ) SEMP

SRIJ N MIRI ( LSEM TAWA

BENT PEKN e MARU

TLOH d u

t 4 i t MERU a MUAD L NIAH UPMS KLAW BANT BAHA BINT KROM MUKA 3 BELA PDIC SEG1 MERS SRTK JUML SIBU KAPI GAJA TGRH 2 PRTS SEMA SPGR UMAS AMAN JHJY TEBE KUKP TGPG 1

99.50 100.00 100.50 101.00 101.50 102.00 102.50 103.00 103.50 104.00 104.50 110 111 112 113 114 115 116 117 118 119 Longitude Longitude (E)

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 7 GNSS HEIGHTING

Relationship between orthometric height, geoid and ellipsoid H = h - N where: 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)

FLOWCHART OF GNSS HEIGHTING

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 8 GNSS-DERIVED ORTHOMETRIC HEIGHT - Recommended Guidelines

Field Procedure No. Items Parameter 1. Observation Static positioning Technique 2. GNSSControl Atleast3stations 3. Observation At least 2 independent sessions Sessions 4. Station Connections At least 3 independent baselines 5. VDOP Less than 6 (90% of the observation session) 6. ElevationAngle Above10 ° 7. Satellite Tracking At least 5 satellites with GDOP of less than 6 8. Equipment As regulated Calibration 9. MyRTKnet Usage As regulated

Recommended Guidelines (contd.)

Office Procedure No. Items Parameter 1. General Procedure Prescribed procedures as provided in manufacturer manual must be followed. 2. Datum GDM2000 3. Ephemerides Short baselines of less than 30 km: Broadcast. Long baselines: precise. 4. Baseline Processing RMS less than 2 cm. Quality 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 Constrained 1 control station fixed in GDM2000 coordinates. Adjustment 7. Quality Indicator Pass Chi-squares test at 95% confident region. All baselines must pass the local test. 8. Test on Control Relative precision must be less than 2 ppm (2D) Stations and 3 ppm on the vertical component. 9. Over-constrained At least 2 control stations must be fixed in the Adjustment final adjustment. Note: The office procedures are carried out using Trimble Geomatic Office (TGO) software

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 9 CASE STUDIES

Method - either RTK or static technique on BMs Results - horizontal positions (lat & long) and vertical positions (ellipsoidal height) Compare to the levelling height

GNSS observation in progress

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 10 RESULTS - CASE STUDY 1

Difference Between GNSS No. of Observation Heighting & Levelling (cm)

< 1 3

CASE STUDIY 2

Peninsular Malaysia

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 11 RESULTS - CASE STUDY 2

Difference Between GNSS No. of Observation & Heighting & Levelling (%) (cm) < 10 59 (77 %) 10 –18.8 18 (23%)

RESULTS - CASE STUDY 2 (contd.)

0.3 0.25 0.2 0.15 0.1 0.05 0 -0.05 0.00 m -0.1 Different in meter Different -0.15 -0.2 -0.25 -0.3 Scatter plot of the difference between Orthometric Heights DerivedTotal Points GNSS Observed and Levelling

BMs observed in Pahang BMs observed in BMs observed in Johor BMs observed in BMs observed in Melaka BMs observed in Kelantan BMs observed in Selangor BMs observed in Negeri Sembilan SBMs BMs observed in Terenganu BMs observed in

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 12 CASE STUDY 3

Tanjung Malim, Perak

GNSS observations with static technique involving a total number of 11 bench marks (BM)

RESULTS - CASE STUDY 3

Difference Between GNSS No. of Observation & Heighting & Levelling (%) (cm) < 10 7 (64 %) 10 – 16.2 4 (36%)

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 13 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 in enhancing the determination of heighting using GNSS.

The conventional spirit levelling requires a lot of time and is a costly operation as well as 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 14 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 15 Look Forward To Meeting You In Kuala Lumpur In June 2011 and 2014

Thank you for your attention ....

FIG Working Week 2011 Bridging the Gap between Cultures Marrakech, Morocco, 18‐22 May 2011 16