maintaining the National Spatial Reference System. This is carried out through the setting up of ... more maintaining the National Spatial Reference System. This is carried out through the setting up of a surveying infrastructure that includes horizontal and vertical survey controls throughout the country for the eventual purpose of national development, security and defence. In line with the government’s efforts to enhance its public delivery system, one of the many initiatives undertaken by JUPEM is through the use of real-time GNSS survey technology for the dissemination of various geodetic products and services. Since 1997, JUPEM has been developing the capability for real-time data streaming from a network of continuously operating reference stations. Currently there are 78 stations, with spacing of between 30 to 120 km, providing real-time corrections with a latency of under one second using Virtual Reference Station (VRS) technique. Each station of the network is equipped with a high precision dual frequency GPS receiver that is operational 24 hours daily. The acquired GPS data i...
Airborne gravimetry is an effective tool for mapping local gravity fields using a combination of ... more Airborne gravimetry is an effective tool for mapping local gravity fields using a combination of airborne sensors, aircraft and positioning systems. It is suitable for gravity surveys over difficult terrains and areas mixed with land and ocean. This paper describes the geological mapping of Sabah using airborne gravity surveys. Airborne gravity data over land areas of Sabah has been combined with the marine airborne gravity data to provide a seamless land-to-sea gravity field coverage in order to produce the geological mapping. Free-air and Bouguer anomaly maps (density 2.67 g/cm 3 ) have been derived from the airborne data both as simple ad-hoc plots (at aircraft altitude), and as final plots from the downward continued airborne data, processed as part of the geoids determination. Data are gridded at 0.025 degree spacing which is about 2.7 km and the data resolution of the filtered airborne gravity data were 5-6 km. The airborne gravity survey database for land and marine areas has...
Establishment of vertical datum for land related surveying works using conventional levelling tec... more Establishment of vertical datum for land related surveying works using conventional levelling technique is a tedious process. With the advent of GPS (Global Positioning System) technology, determination of heights value for vertical datum in engineering works and alike seems feasible. In this study, two approaches in height determination using GPS are explored. The two technique involve are the absolute and relative GPS heighting. In the absolute technique, the ellipsoidal heights obtained through GPS observation for the observed points are transformed to the orthometric heights (H) by applying the respective geoidal separation value (N). In this technique, only one GPS is needed for the observation. However, for the determination of horizontal position (x,y), the processing will integrate the MyRTKnet (Malaysian Real Time Kinematic Network) as base station. As for the relative approached, two GPS receiver are needed. One of the GPS receivers will be placed at a known point with kno...
maintaining the National Spatial Reference System. This is carried out through the setting up of ... more maintaining the National Spatial Reference System. This is carried out through the setting up of a surveying infrastructure that includes horizontal and vertical survey controls throughout the country for the eventual purpose of national development, security and defence. In line with the government’s efforts to enhance its public delivery system, one of the many initiatives undertaken by JUPEM is through the use of real-time GNSS survey technology for the dissemination of various geodetic products and services. Since 1997, JUPEM has been developing the capability for real-time data streaming from a network of continuously operating reference stations. Currently there are 78 stations, with spacing of between 30 to 120 km, providing real-time corrections with a latency of under one second using Virtual Reference Station (VRS) technique. Each station of the network is equipped with a high precision dual frequency GPS receiver that is operational 24 hours daily. The acquired GPS data i...
Airborne gravimetry is an effective tool for mapping local gravity fields using a combination of ... more Airborne gravimetry is an effective tool for mapping local gravity fields using a combination of airborne sensors, aircraft and positioning systems. It is suitable for gravity surveys over difficult terrains and areas mixed with land and ocean. This paper describes the geological mapping of Sabah using airborne gravity surveys. Airborne gravity data over land areas of Sabah has been combined with the marine airborne gravity data to provide a seamless land-to-sea gravity field coverage in order to produce the geological mapping. Free-air and Bouguer anomaly maps (density 2.67 g/cm 3 ) have been derived from the airborne data both as simple ad-hoc plots (at aircraft altitude), and as final plots from the downward continued airborne data, processed as part of the geoids determination. Data are gridded at 0.025 degree spacing which is about 2.7 km and the data resolution of the filtered airborne gravity data were 5-6 km. The airborne gravity survey database for land and marine areas has...
Establishment of vertical datum for land related surveying works using conventional levelling tec... more Establishment of vertical datum for land related surveying works using conventional levelling technique is a tedious process. With the advent of GPS (Global Positioning System) technology, determination of heights value for vertical datum in engineering works and alike seems feasible. In this study, two approaches in height determination using GPS are explored. The two technique involve are the absolute and relative GPS heighting. In the absolute technique, the ellipsoidal heights obtained through GPS observation for the observed points are transformed to the orthometric heights (H) by applying the respective geoidal separation value (N). In this technique, only one GPS is needed for the observation. However, for the determination of horizontal position (x,y), the processing will integrate the MyRTKnet (Malaysian Real Time Kinematic Network) as base station. As for the relative approached, two GPS receiver are needed. One of the GPS receivers will be placed at a known point with kno...
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