Relevance of Reference Frame to the Region and Industry - Malaysian Experience

Transcription

1 Relevance of Reference Frame to the Region and Industry - Malaysian Experience David Chang Leng Hua Geodesy Section Mapping Division, Department of Survey and Mapping Malaysia 7 th Regional Conference 2009, Hanoi, Vietnam 1 CONTENTS INTRODUCTION OLD TRIANGULATION NETWORKS GNSS-BASED NETWORKS GEOCENTRIC DATUM OF MALAYSIA (GDM2000) REVISION OF GDM2000 CONCLUSION 7 th Regional Conference 2009, Hanoi, Vietnam 2 1

2 INTRODUCTION Coordinate reference systems in regions around the world - 19th century, conventional surveying techniques and procedures IUGG through its 1991 resolution which recommend the establishment of Reference System in geocentric non-rotating system that is identical to Global Reference System (GRS) as defined in the IAU resolutions Advent of advances in space-based positioning technology, many countries have implemented and adopted a global geocentric coordinate reference system 7 th Regional Conference 2009, Hanoi, Vietnam 3 INTRODUCTION JUPEM has embarked in the early 1990s on the Global Positioning System (GPS) technology bandwagon with the objective of adopting a global unified datum for Peninsula Malaysia, Sabah, and Sarawak Established permanent GPS tracking stations known as Malaysia Active GPS System (MASS) at the end of 1998 that comprises eighteen (18) permanent GPS tracking stations. 7 th Regional Conference 2009, Hanoi, Vietnam 4 2

3 INTRODUCTION Obtained GPS data from the International Global Navigational Satellite System (GNSS) Service (IGS) stations Geocentric Datum of Malaysia 2000 (GDM2000) using data from Establish the Malaysia Real-Time Kinematic GNSS Network or MyRTKnet in 2003 Revise the coordinate reference systems, using GPS data from the years 2006 to 2008 of MyRTKnet and IGS stations 7 th Regional Conference 2009, Hanoi, Vietnam 5 OLD TRIANGULATION NETWORKS Malayan Revised Triangulation 1968 (MRT68) 7 th Regional Conference 2009, Hanoi, Vietnam 6 3

4 OLD TRIANGULATION NETWORKS Borneo Triangulation 1968 (BT68) 7 th Regional Conference 2009, Hanoi, Vietnam 7 GNSS-BASED NETWORKS Space based positioning satellites revolve around the center of mass of the earth and are therefore related to an earth-centered or geocentric datum JUPEM has established a GPS network of 238 stations in Peninsular Malaysia, called the Peninsular Malaysia Geodetic Scientific Network 1994 (PMGSN94) and 171 stations in Sabah and Sarawak called East Malaysia Geodetic Scientific Network 1997 (EMGSN97). 7 th Regional Conference 2009, Hanoi, Vietnam 8 4

5 GEOCENTRIC DATUM OF MALAYSIA (GDM2000) Malaysia Active GPS Network or MASS is a permanent GPS network that was established in 1999 and formed a homogeneous and coherent network, covering the whole of Malaysia. The MASS station GPS data were used along with those from the International GNSS Service (IGS) stations for the realization of the zero-order geodetic network for Malaysia 7 th Regional Conference 2009, Hanoi, Vietnam 9 GEOCENTRIC DATUM OF MALAYSIA (GDM2000) GPS data from seventeen (17) MASS stations and eleven (11) IGS stations from 1999 to 2002 have been processed to establish the zero-order geodetic network. The eleven (11) permanent GPS tracking stations of the IGS world-wide network in ITRF2000 Epoch 1997 were used as fiducial points in the processing to obtain the MASS set of station coordinates 7 th Regional Conference 2009, Hanoi, Vietnam 10 5

6 GEOCENTRIC DATUM OF MALAYSIA (GDM2000) 7th Regional Conference 2009, Hanoi, Vietnam 11 GEOCENTRIC DATUM OF MALAYSIA (GDM2000) LHAS SHAO KUNM WUHN PIMO IISC GUAM NTUS BAKO COCO KARR 7th Regional Conference 2009, Hanoi, Vietnam 12 6

7 GEOCENTRIC DATUM OF MALAYSIA (GDM2000) The reference IGS station coordinates which are in ITRF2000 at epoch were transformed to the same epoch as the adjusted MASS station coordinates, i.e. ITRF 2000 at epoch These new set of coordinates are known as the Geocentric Datum of Malaysia or GDM2000 and was officially launched on 26 August th Regional Conference 2009, Hanoi, Vietnam 13 Malaysian Primary Geodetic Network 2000 (MPGN2000) 6 Latitude Longitude 7 th Regional Conference 2009, Hanoi, Vietnam 14 7

8 MALAYSIA REAL-TIME KINEMATIC GNSS NETWORK (MYRTKNET) ARAUUMK LGKW GETI 7 KUDA Latitude TOKA SIK1 PASP AYER SGPT KRAI SETI GRIK USMP KUAL BABH TERI LASA GMUS MUKH PUSI CAME PUPK LIPI CENE TLKI JRNT SBKB BEHR SRIJ BENT TLOH PEKN MERU MUAD UPMS KLAW BANT BAHA KROM PDIC SEG1 MERS JUML GAJA TGRH PRTS SPGR Latitude (N) SEMA UMAS S SIBU R AMAN MUKA BINT KAPI MIRI BELA MARU LAB1 LIMB LAWA NI A H LSEM KBEL M UMSS RANA R D BEAU R KENI U TENO A JAMB SAND TAWA LAHA TUNK SEMP 1.50 JHJY KUKP TGPG 1 TEBE Longitude Longitude (E) 7 th Regional Conference 2009, Hanoi, Vietnam 15 REVISION OF GDM2000 MAJOR SUMATRAN EARTHQUAKES IN 2004, 2005 AND 2007 When these natural catastrophes occurred, three types of motions were generated: Pre-seismic motion: earth movement before the incident of earthquake. Co-seismic motion: earth movement at the incident of earthquake. Post-seismic motion: earth movement after the incident of earthquake. 7 th Regional Conference 2009, Hanoi, Vietnam 16 8

9 Pre-seismic motion 7 th Regional Conference 2009, Hanoi, Vietnam 17 Co-seismic motion The co-seismic motion was deduced by comparing the coordinates of MyRTKnet stations computed using GPS data during the first week before the earthquake with those during the second week after the event. Results indicate that the displacement of the MyRTKnet stations due to the co-seismic motion from the 2004 earthquake in Sumatra was between 1.5 to 17 cm, occurring predominantly in the south-west direction. Similarly, the results from 2005 and 2007 earthquakes indicate displacement of between 1.0 to 6.5 cm and 1.0 to 3 cm respectively, also in the south-west direction 7 th Regional Conference 2009, Hanoi, Vietnam 18 9

10 Post-seismic motion (2006) 7 th Regional Conference 2009, Hanoi, Vietnam 19 Post-seismic motion (2007) 7 th Regional Conference 2009, Hanoi, Vietnam 20 10

11 Post-seismic motion (2008) 7 th Regional Conference 2009, Hanoi, Vietnam 21 Accumulated displacement of MyRTKnet stations from 26 December 2004 to 30 April th Regional Conference 2009, Hanoi, Vietnam 22 11

12 REVISION OF GDM2000 GPS data from seventy-eight (78) MyRTKnet stations and fifty-six (56) IGS stations in ITRF2005 for the years 2006 to 2009 were used in the data processing to re-establish the zero order geodetic network. However, only thirty-three (33) IGS stations were used as fiducial points in the processing to obtain the MyRTKnet set of station coordinates. These IGS stations which are in ITRF2005 at epoch were then brought to ITRF2000 at epoch using published velocity models. 7 th Regional Conference 2009, Hanoi, Vietnam 23 REVISION OF GDM2000 The combined adjustment for these data was fixed at epoch 1 January 2000 and the resulting coordinates named as GDM2000 (2009). Comparison with the original GDM2000@ coordinates was carried out by using three parameter Helmert transformation process and results indicate that the RMS fitting for the coordinates of four (4) reference stations (KUCH, BINT, KINA and MIRI) were less than one (1) cm in the north, east and height components. Other stations saw large displacements which were possibly caused by the earthquake or some seasonal environmental effect. 7 th Regional Conference 2009, Hanoi, Vietnam 24 12

13 REVISION OF GDM2000 The final combined adjustment used the original GDM2000 reference frame as the reference by holding the coordinates of four (4) stations fixed. With this adjustment, the resulting coordinates of the MyRTKnet stations were obtained in GDM2000 (2009) 7 th Regional Conference 2009, Hanoi, Vietnam 25 REVISION OF GDM2000 Apart from producing MyRTKnet stations in GDM2000 (2009) coordinates, similar efforts were also made for the MPGN2000 stations. Thus, with the availability of GDM2000 (2009) coordinates for all the MyRTKnet stations, the next step is to revise the GDM2000 coordinates of the MPGN2000 stations, bearing in mind that stations in Sabah and Sarawak still maintain their GDM2000 coordinates due to insignificant displacements from the two earthquakes in Sumatra 7 th Regional Conference 2009, Hanoi, Vietnam 26 13

14 CONCLUSION Malaysia has successfully established both active and passive GNSS networks to replace the old triangulation networks in Malaysia. These new networks will facilitate the development and enhancement of various surveying and mapping activities and meet the requirements of all types of users, ranging from the novice to the scientists. 7 th Regional Conference 2009, Hanoi, Vietnam 27 CONCLUSION The GDM2000 supersedes the classical geodetic datums in Malaysia and has been established with respect to a geocentric reference frame defined in ITRF system at ITRF2000 epoch 2 January 2000 at an accuracy of 1 cm. On the other hand, the new GDM2000 (2009) coordinates have taken into account the displacement and movement due to the Sumatran earthquakes in 2004, 2005 and This new GDM2000 (2009) would be continuously maintained and managed through the use of MyRTKnet permanent tracking stations to ensure the availability of highly accurate, homogeneous and up-to-date datum of Malaysia 7 th Regional Conference 2009, Hanoi, Vietnam 28 14

15 CONCLUSION The OGP Surveying and Positioning Committee recommends the following: To use only reference stations of commercial WADGPS system which have been tied to the ITRF at decimeter or better accuracy To tie to the ITRF any local geodetic framework used in the past for offshore or inshore oil industry surveys 7 th Regional Conference 2009, Hanoi, Vietnam 29 CONCLUSION Geoinformation system need an unambiguous spatial reference of the acquired information. The standardisation of the reference frame could provide that requirement a reality 7 th Regional Conference 2009, Hanoi, Vietnam 30 15