Papers by Nurrohmat Widjajanti
Journal of Applied Geodesy
We analyze the Global Positioning System (GPS)-derived strain rate distribution to investigate ac... more We analyze the Global Positioning System (GPS)-derived strain rate distribution to investigate active crustal structure in Central Java, Indonesia, using ten years (2010–2019) continuous and permanent observation data. Central Java is the third-most populous province in Indonesia where postseismic deformation of devastating Yogyakarta earthquake in 2006 might influence the GPS data. The postseismic extensional response might overshadow the low contractional process due to active tectonics deformation. A decomposition method of a calculated strain rate shows a long wavelength feature with the extensional region in the vicinity of the 2006 Yogyakarta earthquake may reflect the postseismic process remain active. The short wavelength pattern is sharpening potential active tectonics dominated by oblique Northwest-Southeast dip-slip motion with East-West left-lateral sense. Our result demonstrates essential implications for assessing future seismic hazard potential within a low strain rat...
Network design used to get the optimal network. There are four stages in GPS network design that ... more Network design used to get the optimal network. There are four stages in GPS network design that is Zero, First, Second, and Third Order Designs. First Order Design is the way of network design to get optimal GPS network geometry. In the First Order Design, there are 2 criteria to determine the network optimality level. These are accuracy and reliability criteria. This research try for designing optimal network based on accuracy and reliability criteria. There are 5 network designs, from which relative less complex to the most complex, located at UGM. The computation of optimization use least square adjusment to determine variance-covariance of parameter, cofactor matrix of parameter and residual. The value of variance-covariance of parameter, cofactor matrix of parameter and residual are used to calculate the accuracy and reliability criteria. Optimum network design in terms of accuracy can be seen from accuracy criteria. The smaller value of accuracy criteria, the network is getti...
Processing of long baseline GPS data needs specific requirement. This is due to the difficulty of... more Processing of long baseline GPS data needs specific requirement. This is due to the difficulty of ambiguity resolution for this particular reference-rover long distance (above 100 km). Distance and number of reference stations are significant factors affecting the quality of network configuration. These two things have to be determined in order to have an effective design of network configuration. This will lead higher positioning accuracy and precision. This paper presents a study on the designing of some network configuration in processing long baseline GPS. A simulation is conducted to examine the influence of number and distance of GPS stations. Two permanent stations; International Global Station (IGS) and Malaysian primary GPS station, are used for the references. The data used in this simulation are obtained from GPS offshore platform. Scientific software is used for data processing instead of commercial software since the latter are limited only for short baselines processin...
JGISE: Journal of Geospatial Information Science and Engineering
Ketersediaan layanan dan cakupan Continuously Operating Reference Station (CORS) sangat penting u... more Ketersediaan layanan dan cakupan Continuously Operating Reference Station (CORS) sangat penting untuk kegiatan yang membutuhkan ketelitian level sentimeter atau lebih baik. Penelitian ini menganalisis ketersediaan layanan CORS Indonesia berdasar data web scraping server InaCORS pada Desember 2018. Cakupan CORS diestimasi dengan asumsi performansi Real Time Kinematic (RTK) single base hingga radius 30 kilometer dan untuk RTK network base hingga 50 kilometer dari masing-masing stasiun yang kemudian dipadukan dengan data cakupan jaringan komunikasi selular Telkomsel, Indosat dan 3 dari opensignal.com. Hasil web scraping menunjukkan terdapat 51 stasiun CORS dengan ketersediaan layanan di atas 80%, empat dengan ketersediaan layanan di bawah 80%, dua dengan ketersediaan layanan di bawah 50%, dan 14 yang tidak memiliki ketersediaan layanan. Cakupan CORS untuk metode RTK single base dan network base masing-masing adalah 72,942% dan 98,299%. Luas cakupan CORS terbesar diperoleh provider Telk...
IOP Conference Series: Earth and Environmental Science, 2021
The postseismic effects of the 2006 Yogyakarta earthquake was caused by the Opak Fault activity a... more The postseismic effects of the 2006 Yogyakarta earthquake was caused by the Opak Fault activity as the possible source still continues. Secular velocity analysis who referred to the velocity which is free from the other deformations than interseismic deformation needs to be done to represent local deformation of the fault. This study was conducted to determine the significance of the difference between the secular velocity without and with postseismic corrections. The secular velocity is determined by the linear least square method. Furthermore, the velocity is calculated its postseismic correction with logarithmic method. This research data includes CORS BIG and Opak Fault station observation data from 2013 to 2018 which is processed using GAMIT/GLRED. Furthermore, the time series data for each station is plotted and analysed, then it is visualized its velocity. The result of this study shows the value of secular velocity each station ranges from 21.676 to 30.997 mm/year and −14.11...
Pengamatan Global Navigation Satellite System (GNSS) di wilayah Sesar Opak sudah mulai dilakukan ... more Pengamatan Global Navigation Satellite System (GNSS) di wilayah Sesar Opak sudah mulai dilakukan sejak tahun 2013 dan diukur secara berkala setiap tahunnya. Studi geodinamika di wilayah Sesar Opak sejauh ini hanya berfokus pada nilai koordinat, besar, dan arah gerakan dari titik pantau Sesar Opak. Metode estimasi vektor kecepatan titik pantau Sesar Opak yang digunakan selama ini yaitu Teknik Kalman Filtering pada pengolahan GAMIT/GLOBK dan belum mengevaluasi perubahan tidak linier dari data yang digunakan. Pemantauan dan prediksi dari deformasi suatu objek merupakan pokok penting dalam studi geodinamik. Model prediksi pergerakan suatu struktur objek yang dikaji dapat dibuat berdasarkan pola statistik dari data yang tersedia. Prediksi pergerakan objek yang terdeformasi dapat menjadi early warning system dalam meminimalisirkan bencana alam. Prediksi pergerakan Sesar Opak dilakukan dengan membandingkan metode Kalman Filtering dan model Autoregressive Integrated Moving Average (ARIMA). ...
Kepemilikan terhadap ruang mudah dikenali dalam representasi kadaster 3D. Representasi sistem kad... more Kepemilikan terhadap ruang mudah dikenali dalam representasi kadaster 3D. Representasi sistem kadaster 3D membutuhkan kerangka teknis dalam hal ketelitian posisi dan syarat-syarat teknis. Dalam sistem kadaster 3D, sistem tinggi yang mempunyai georeferensi pada sistem koordinat tertentu dapat menentukan lokasi properti. Seiring dengan perkembangan kadaster 3D dalam beberapa dekade terakhir, berkembang juga teknologi termasuk akuisisi data kadaster 3D, validasi data, dan visualisasi data untuk memenuhi kebutuhan dasar kadaster 3D. Fokus penelitian ini yaitu pada aspek teknis dalam pembangunan kadaster 3D. Tujuan paper ini yaitu menyediakan data kadaster 3D dalam membangun sistem kadaster digital, validasi, dan pemodelan kadaster 3D. Pengukuran objek kadaster 3D secara teliti, baik secara horizontal dan vertikal didukung oleh teknologi pengukuran yang berkembang sangat pesat, seperti GNSS dan laser scanner. BLK360 adalah Terrestrial Laser Scanner (TLS) yang menggunakan teknologi Inerti...
2019 5th International Conference on Science and Technology (ICST), 2019
Special Region of Yogyakarta is one of the Indonesian regions with high seismic activity. Subduct... more Special Region of Yogyakarta is one of the Indonesian regions with high seismic activity. Subduction zones and onland fault structures influence these activities. One of onland fault structures that affect this region is the Opak Fault. Therefore, deformation monitoring is required. This study used five years of geodetic data that is acquired periodically. The deformation rate of Global Navigation Satellite System (GNSS) station around the Opak Fault ranging from 5.73 to 23.59 mm/yr and -30.16 to 118.61 mm/yr for horizontal and vertical components with respect to Sundaland Block, respectively. Those deformation rates have been reduced by Sundaland Block effect but have not deliberate error and noise from the other effects. The estimated deformation rate is used to compute the preliminary deformation model. The strain rate analysis suggests that the western region of the fault is dominated by compression. Meanwhile, the eastern region of the fault is dominated by extension.
2019 5th International Conference on Science and Technology (ICST), 2019
Opak Fault is an active fault where located in Special Region of Yogyakarta which need to be moni... more Opak Fault is an active fault where located in Special Region of Yogyakarta which need to be monitored because of high seismic potential. GNSS observation along Opak Fault has been deployed periodically since 2013 to 2018 by Department of Geodetic Engineering Universitas Gadjah Mada. This study present displacement rate and crustal movement prediction along Opak Fault using GNSS campaign data. The result show these rates are about 7.81 to 17.52 mm/yr, 0.43 to - 16.52 mm/yr, and 0.43 to -16.52 mm/yr for east, north, and up components respectively. The displacement rate direct to south east side. However, alternative approach of estimation model for crustal movement is need to be evaluated to gain more robust estimation. This study estimate crustal movement along Opak Fault using Kalman Filtering. The estimation accuracy of this filtering is about -0.042 to 2.680 mm of Mean Absolute Error (MAE) and 9.853E-15% to 4.396E-05% of Mean Relative Percentage Error (MRPE).
One important componentin the3Dcadastral system isthe definition of height component. The height ... more One important componentin the3Dcadastral system isthe definition of height component. The height of a cadastral objectis the height above a certain height reference field. Based on theconceptandits use, there aremany height reference fields. Each reference field will have a certain effect on the type of height system and on the corresponding precision. The absoluteheightisdefinedin reference to thenationalheight reference, which provides certaintyandclear geometricandtopologicalrelationsfor3Dcadastralobjects. However, the ideal nationalheight reference field,in this case precise geoidmodels has not been definedfor thewhole of Indonesia.An alternativesolution to the problem uses a definition ofa localgeoidmodel or the use ofa high-resolutionglobalgeoidmodel, the EGM2008. In the implementation, the precision level of the available geoid model and the required precision level of cadastral objects height become the basis for the selection of a geoid model. The use ofthe geoid modelasthe...
2018 4th International Conference on Science and Technology (ICST), 2018
Conversion of geodetic height to orthometric height requires geoid to transform geometric elevati... more Conversion of geodetic height to orthometric height requires geoid to transform geometric elevation above ellipsoid into physical elevation above mean sea level. The need of accurate geoid is increasing as many leveling benchmarks have lost and deformed due to city development and natural activities. This paper presents geoid determination based on combination of gravity disturbances data and gravity anomalies data. Gravity disturbances were computed from 185 terrestrial gravity data. Gravity data were measured on March 2016 using Scintrex CG-5 gravimeter. All gravity stations coordinates were measured using rapid static method of GNSS to achieve sub-meter accuracy. Gravity anomalies data for improving the accuracy of the geoid models were measured by some government and private agencies using analogue gravimeters. It consisted of 10,149 data and covered whole Java island which was not less than 2 arc degree of latitude by 10 arc degree of longitude. Gravity disturbances of the city...
Previous studies on nonitoring Borobudur’s horizontal deformation have shown that the traverse pr... more Previous studies on nonitoring Borobudur’s horizontal deformation have shown that the traverse precisions have not met the requirement standar for deformation analysis. This can be caused by inaccurate measurements of the angles or distance of closed traverse and the minimum redundancy number in adjustment computation. This study aims to analyze the strength of figure of horizontal deformation monitoring network from previous study and evaluate new design of monitoring netwoks which are measured using Total Station. The research is done firstly by evaluating the strength of figure of horizontal deformation network as observed in 2011. Based on this evaluation, new observations of three different network design using Nikon DTM 352 Total Station has been done. Data from the measurement are then processed using the least square adjustment method using minimal constraints. Global test conducted to evaluate the result of the adjustment computation. Further evaluation of the strength of f...
Indonesian Journal of Geography, 2019
The condition of the geological structure in the surrounding Sermo reservoir shows that there is ... more The condition of the geological structure in the surrounding Sermo reservoir shows that there is a fault crossing the reservoir. Deformation monitoring of that fault has been carried out by conducting GNSS campaigns at 15 monitoring stations simultaneously. However, those campaigns were not well designed. With such a design, it took many instruments and spent much money. For the next GNSS campaign, it should be designed so that the optimal network configuration is obtained and the cost can be reduced. In the design of deformation monitoring network, sensitivity criteria become very important for detecting the deformations. In GNSS relative positioning, the baseline components are correlated, but this correlation is often ignored. This research examined the effect of baseline component correlations on the design results of the GNSS configuration of the Sermo Fault network based on sensitivity criterion. In this case, the western side of the fault was taken as a reference, while the o...
JGISE: Journal of Geospatial Information Science and Engineering, 2021
Ketersediaan layanan dan cakupan Continuously Operating Reference Station (CORS) sangat penting u... more Ketersediaan layanan dan cakupan Continuously Operating Reference Station (CORS) sangat penting untuk kegiatan yang membutuhkan ketelitian level sentimeter atau lebih baik. Penelitian ini menganalisis ketersediaan layanan CORS Indonesia berdasar data web scraping server InaCORS pada Desember 2018. Cakupan CORS diestimasi dengan asumsi performansi Real Time Kinematic (RTK) single base hingga radius 30 kilometer dan untuk RTK network base hingga 50 kilometer dari masing-masing stasiun yang kemudian dipadukan dengan data cakupan jaringan komunikasi selular Telkomsel, Indosat dan 3 dari opensignal.com. Hasil web scraping menunjukkan terdapat 51 stasiun CORS dengan ketersediaan layanan di atas 80%, empat dengan ketersediaan layanan di bawah 80%, dua dengan ketersediaan layanan di bawah 50%, dan 14 yang tidak memiliki ketersediaan layanan. Cakupan CORS untuk metode RTK single base dan network base masing-masing adalah 72,942% dan 98,299%. Luas cakupan CORS terbesar diperoleh provider Telk...
The use of Global Positioning System (GPS) for positioning, mapping and navigation has been rapid... more The use of Global Positioning System (GPS) for positioning, mapping and navigation has been rapidly developed. Different application scenarios and accuracy levels require different receiver classes, from a high-end geodetic receiver to a low-cost handheld receiver. Handheld GPS receiver has been employed only for recreational purposes where low-accuracy will suffice. This is because handheld GPS only provides real-time position which utilizes C/A code (Coarse Acquisition) where the accuracy is commonly at a few meters. Some handheld GPS receivers use carrier-smoothed code to produce more precise position. Theoretically, the use of either P code or L1 carrier phase for differential postprocessed positioning will provide higher accuracy up to decimeter or centimeter level. For this current experiment, a low-cost handheld GPS receiver, Garmin eTrex Vista, was applied as the main equipment and was compared to a set of standard geodetic GPS receiver. The L1 carrier phase and the P code d...
Indonesian Journal of Geography, 2021
Use and development of vertical building(s) on land parcel(s) have been a common progress to many... more Use and development of vertical building(s) on land parcel(s) have been a common progress to many urban landscapes around the world. 3D cadastre has been a research area that involves legal, technical and institutional assessments to the use and development of vertical buildings. Initial Land Registration of 3D cadastre objects require a representative geometry to determine the legal boundaries of 3D objects. For that purpose, a height reference that is used to define 3D geometries of registered 3D cadastre objects is important. This study focuses in determining a height reference system by developing a local hybrid geoid for the representation of 3D cadastre. The local hybrid geoid was developed by fitting the gravimetric to the geometric geoid. Four strategies were utilized, based on the combination of GGM’s SGG-UGM-1 and GO_CONS_GCF_2_SPW_R5, Remove-Compute-Restore method and control point distribution for geoid fitting. Based on comparison with geometric geoid at six independen...
CORS or Continuously Operating Reference Station is a positioning technology based on GNSS (Globa... more CORS or Continuously Operating Reference Station is a positioning technology based on GNSS (Global Navigation Satellite System). Nowadays, CORS is developed by Badan Pertanahan Nasional (BPN RI). One example of the use of CORS is for maintenance of the Cadastral Control Point third order (3 rd order TDTs). Therefore the precision of the coordinates measured using GNSS CORS RTK NTRIP receiver need to be evaluated. The project was done in Bantul regency with 30 samples of the 3 rd order TDTs. The coordinates resulted from RTK NTRIP GNSS CORS method are compared to the coordinates of the buku tugu, which has measured by Leica R 261 receiver with static relative method. The evaluation is carried out using the significance test of horizontal displacement and the tolerance computation of the displacement. The result of this study indicate that the HRMS of the RTK NTRIP method can achieve the centimeter fractions. The result of the significant test concluded that there are a significant di...
Keberadaan Waduk Sermo di Kabupaten Kulonprogo, sangat penting karena manfaatnya sebagai tampunga... more Keberadaan Waduk Sermo di Kabupaten Kulonprogo, sangat penting karena manfaatnya sebagai tampungan air bersih, sarana pariwisata dan saluran irigasi untuk lahan pertanian di sekitarnya. Namun demikian banyak juga yang tidak menyadari bahwa di bawah Waduk Sermo terdapat segmen sesar aktif yang memanjang dari Parangtritis ke Kulonprogo. Penelitian ini bermaksud untuk mengembangkan jaring pengamatan yang telah ada sebelumnya menjadi lebih luas cakupannya untuk mengetahui dampak dari adanya sesar aktif tersebut. Penelitian dilaksanakan dengan beberapa tahapan, yaitu: 1) pengembangan kerangka kontrol, dengan menambah tujuh titik (5 makro dan 2 mikro) jaring kontrol baru; 2) pengukuran kerangka kontrol, dengan menggunakan pengamatan GPS/GNSS metode relatif statik di semua titik kontrol sejumlah 15 titik; 3) pengolahan data, dengan menggunakan perangkat lunak GAMIT/GLOBK dan diolah dalam dua skenario terkait penggunaan titik referensi dalam pengolahan. Hasil dari penelitian ini adalah terb...
2018 4th International Conference on Science and Technology (ICST), 2018
Ministry of Agrarian Affairs and Spatial Planning/National Land Agency (Kementerian Agraria dan T... more Ministry of Agrarian Affairs and Spatial Planning/National Land Agency (Kementerian Agraria dan Tata Ruang (ATR)/Badan Pertanahan Nasional (BPN) utilizes GNSS CORS technology known as JRSP to perform cadastral measurement and mapping. The definition of the GNSS CORS base station coordinates is carried out following the reference system at the time of construction. To produce cadastral measurements with accurate and precision meet the cadastral mapping specifications, it is required reference frame with accurate coordinate. Therefore, the redefinition coordinate of base stations is performed by BPN periodically. These are delivered to monitor and update base station positions to accommodate Indonesian geodynamics and to ajust the specifications. Also, the quality of receivers at the base stations also need to be monitored. The zero baseline tests are used to check the GNSS receiver accuracy. The results of the redefinition and calibration of GNSS CORS receiver show the effect of base...
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Papers by Nurrohmat Widjajanti