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THE EFFECT OF BASELINE COMPONENT CORRELATION ON THE DESIGN OF GNSS NETWORK CONFIGURATION FOR SERMO RESERVOIR DEFORMATION MONITORING Yulaikhah, Yulaikhah; Pramumijoyo, Subagyo; Widjajanti, Nurrohmat
Indonesian Journal of Geography Vol 51, No 2 (2019): Indonesian Journal of Geography
Publisher : Faculty of Geography, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (146.707 KB) | DOI: 10.22146/ijg.44914

Abstract

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 other side as an object moving relatively against the western side. This study found that the baseline component correlation affects the results of GNSS network configuration. Considering the correlation could result a sensitive network configuration with a fewer baseline; therefore, the cost and time of field surveys can be reduced. It can be said that the baseline component correlation needs to be taken into account in the configuration design of deformation monitoring network.
PENGEMBANGAN JARING KONTROL GEODESI PEMANTAU WADUK SERMO Waliyanto, Waliyanto; Widjajanti, Nurrohmat; Yulaikhah, Yulaikhah; Taftazani, M. Iqbal
GEOMATIKA Vol 21, No 2 (2015)
Publisher : Badan Informasi Geospasial in Partnership with MAPIN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (561.113 KB) | DOI: 10.24895/JIG.2015.21-2.581

Abstract

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 terbangunnya pilar/patok jaring pemantauan baru sebagai pengembangan jaring kontrol pemantauan Waduk Sermo, serta koordinat jaring kontrol hasil olahan dalam dua skenario, yaitu: pada skenario pertama, titik makro memiliki simpangan baku terkecil yaitu 0,004 m pada sumbu Z di titik MAK2. Sedangkan pada titik mikro, simpangan baku terkecil sebesar 0,004 m pada sumbu Z di titik BBR1 dan BMS2. Pada skenario kedua, simpangan baku titik makro terkecil yaitu 0,001 m pada sumbu X di titik MAK1. Sedangkan pada titik mikro, simpangan baku terkecil sebesar 0,005 m pada sumbu Z di titik BMS2. Titik-titik yang sudah dibangun dapat bermanfaat untuk memantau pergerakan bendungan dan secara berkala bisa digunakan untuk memantau aktivitas sesar yang berada di bawah Waduk Sermo.Kata kunci: pengembangan JKG, pemantau Waduk Sermo, teknik GPS/GNSS
GEOMETRIC ASPECTS EVALUATION OF GNSS CONTROL NETWORK FOR DEFORMATION MONITORING IN THE JATIGEDE DAM REGION Sanjaya, Made Ditha Ary; Sunantyo, T. Aris; Widjajanti, Nurrohmat
International Journal of Remote Sensing and Earth Sciences (IJReSES) Vol 15, No 2 (2018)
Publisher : National Institute of Aeronautics and Space of Indonesia (LAPAN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30536/j.ijreses.2018.v15.a2901

Abstract

Many factors led to dam construction failure so that deformation monitoring activities is needed in the area of the dam. Deformation monitoring is performed in order to detect a displacement at the control points of the dam. Jatigede Dam deformation monitoring system has been installed and started to operate, but there has been no evaluation of the geometry quality of control networks treated with IGS points for GNSS networks processing. Therefore, this study aims to evaluate the geometric quality of GNSS control networks on deformation monitoring of Jatigede Dam area. This research data includes the GNSS measurements of five CORS Jatigede Dam stations (R01, GG01, GCP04, GCP06, and GCP08) at doy 233 with network configuration scenarios of 12 IGS points on two quadrants (jat1), three quadrants (jat2), and four quadrants (jat3 and jat4). GNSS networks processing was done by GAMIT to obtain baseline vectors, followed by network processing usingparameter method of least squares adjustment. Networks processing with least squares adjustment aims to determine the most optimal  by precision and reliability criterion. Results of this study indicate that network configuration with 12 IGS stations in the two quadrants provides the most accurate coordinates of CORS dam stations. Standard deviations value of CORS station given by jat1 configuration are in the range of 2.7 up to 4.1 cm in X-Z components, whereas standard deviations in the Y component are in the range 5.8 up to 6.9 cm. An optimization assessment based on network strength, precision, and reliability factors shows optimum configuration by jat1.
SISTEM TINGGI DALAM REALISASI KADASTER 3D DI INDONESIA: TANTANGAN, PERMASALAHAN DAN ALTERNATIF SOLUSI Widjajanti, Nurrohmat
BHUMI: Jurnal Agraria dan Pertanahan No 38 (2013): BHUMI
Publisher : Pusat Penelitian Dan Pengabdian Kepada Masyarakat Sekolah Tinggi Pertanahan Nasional

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (600.869 KB) | DOI: 10.31292/jb.v1i38.170

Abstract

One important componentin the3Dcadastral system isthe definition of height component. The height of a cadastralobjectis 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. Theabsoluteheightisdefinedin reference to thenationalheight reference, which provides certaintyandcleargeometricandtopologicalrelationsfor3Dcadastralobjects. However, the ideal nationalheight reference field,in this case precisegeoidmodels has not been definedfor thewhole of Indonesia.An alternativesolution to the problem uses a definition ofalocalgeoidmodel or the use ofa high-resolutionglobalgeoidmodel, the EGM2008. In the implementation, the precision level ofthe available geoid model and the required precision level of cadastral objects height become the basis for the selection of ageoid model. The use ofthe geoid modelasthe height reference has also an impact on theoptimalization/development of theapplication of BPNCORSstationsthatcan beusedas ahorizontal as well as a verticalreferencepointin3Dcadastralmapping.Keywords: 3D cadastre, cadastral mapping, geoid.
Correlation of GNSS Observation Data Quality Resulted from TEQC Checking and Coordinate’s Precision Yulaikhah, Yulaikhah; Pramumijoyo, Subagyo; Widjajanti, Nurrohmat
Jurnal Geospasial Indonesia Vol 1, No 1 (2018): June
Publisher : Department of Geodetic Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jgise.38387

Abstract

GPS Positioning provides good coordinate accuracy that is up to a millimeter. However, some error sources such as multipath, atmospheric conditions and obstruction can reduce the quality of data and also coordinates. To minimize errors due to these factors, at the time of determining the station location, it is necessary to pay attention to the surrounding conditions, namely by looking for open areas and avoiding objects that can reflect GNSS signals. However, it is often not easy to find the ideal observation station location, which forms a good chain while being free from obstruction and multipath. Therefore, it is often necessary to prioritize certain factors over other factors. Information about the correlation between multipath, ionospheric conditions and the recording level of observational data on coordinate accuracy can be used as consideration in determining the location of control points for deformation monitoring and determining which factors are prioritized. This study aims to evaluate the correlation between data quality and coordinates precision.The used observation data are Sermo Reservoir control network and nine CORS BIG stations. The component data analyzed are multipath (MP1, MP2), ionospheric effects (IOD slips and IOD or MP slips) and the data recording level (obs). These components were resulted by checking with TEQC software, while the precision of the coordinates was obtained by processing with GAMIT / GLOBK software. Based on the correlation coefficient value, it is known that the recording level of observation data has the strongest correlation with a negative direction (ranging from -0.7 to -0.9). It is the ratio between the number of real observations to the number of possible ones. One factor that influences it is the obstruction in the field. In other words, in determining the location of GNSS observation stations, the conditions of obstruction in the vicinity need to be considered and prioritized.
GNSS Monitoring Network Optimization Case Study: Opak Fault Deformation, Yogyakarta Widjajanti, Nurrohmat; Emalia, Sherly Shinta; Parseno, Parseno
Jurnal Geospasial Indonesia Vol 1, No 1 (2018): June
Publisher : Department of Geodetic Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jgise.38458

Abstract

Opak fault is a fault located in Opak River area, Bantul. The existence of the fault is one of the biggest causes of earthquake in Yogyakarta in 2006. The seismic potential caused by the active fault requires continuous geodynamic monitoring. The GNSS network (TGD, SGY, and OPK) have been developed since 2013 consists of 17 stations and in 2016 there was an additional number of four monitoring stations. Several high-precision monitoring stations distributed at the fault location are needed to monitor the fault movement. Optimal observation network is one of the factors to obtain high precision station coordinates. The GNSS network optimization has been carried out in the previous research partially on each network; namely the segment of TGD, SGY, and OPK. Therefore, this research conducts a thoroughly optimization for 17 monitoring stations either use old or new stations to obtain an optimal network based on the criteria of accuracy and reliability.The network is designed widely from simple to complex combination and to combination between network segments. The computation uses least squares adjustment with parameter method. The value of the cofactor matrix parameter of the adjustment is applied to analyze the network based on the function of the accuracy criteria, namely A-Optimality, D-Optimality, E-Optimality, S-Optimality, and I-Optimality. Meanwhile, the value of the residual cofactor matrix is used for network configuration analysis based on the reliability objective function, namely the individual redundancy, external and internal reliabilities criteria. The result showed that the design of TGD, SGY and OPK network segments are optimized based on the criteria of accuracy and reliability if they use a network design with a complex baseline. The criteria for accuracy and reliability in the design with a combination of segments such as TGD and SGY, TGD and OPK, as well as TGD, SGY, and OPK are not much different from the optimization results performed by each segment. Therefore, if the measurements are carried out with a limited receiver, it is better to use each of segment designs.
Analysis of the July 10th 2013 Tectonic Earthquake effect on the Coordinates Changes of Mentawai Segment Monitoring Station Ulinnuha, Hilmiyati; Sunantyo, Aris; Widjajanti, Nurrohmat
Jurnal Geospasial Indonesia Vol 1, No 2 (2018): December
Publisher : Department of Geodetic Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jgise.39350

Abstract

Mentawai Segment is located in Mentawai Islands, Sumatra, Indonesia. This segment is a subduction zone between Indo-Australian plate and Eurasian plate. This subduction zone can lead to high potential of tectonic earthquake in Mentawai Segment. The high potential of tectonic earthquake has negative impact for the community, so it is necessary to monitor the risk of tectonic earthquake in Mentawai Segment. This monitoring can be done by using GPS data of monitoring station that spread in Mentawai Segment. Therefore, this research aims to analyze the effect of tectonic earthquake on the coordinate change of Mentawai Segment, so that it can reduce the risk of negative impact of tectonic earthquake in Mentawai Segment. This research use observation data of 10 continuous GPS monitoring station (Sumatran GPS Data Array / SuGAr) in Mentawai Segment. Day of observation data was day of year (doy) at the time of tectonic earthquake occurence on July 10, 2013. Data processing used GAMIT / GLOBK software. The results of this research indicate that the tectonic earthquake (July 10, 2013) affected coordinates changes of the SuGAr station significantly two hours after the tectonic earthquake occurred.
GPS Technology Implementation for Sangihe Islands' Movement Monitoring in 2017-2019 Ulinnuha, Hilmiyati; Lestari, Dwi; Heliani, Leni Sophia; Widjajanti, Nurrohmat; Pratama, Cecep; Parseno, Parseno; Nugroho, Krishna Fitranto
Jurnal Geospasial Indonesia Vol 2, No 2 (2019): December
Publisher : Department of Geodetic Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jgise.51033

Abstract

Sangihe Islands belong to a complex tectonic area at the subduction of the Eurasian plate and the Philippine Sea. Sangihe subduction zones are complex subduction zone, so that there is a need for continuous movement monitoring. Previous research had been carried out to monitor movement of the Sangihe subduction zone, but no monitoring has been done in 2019. Therefore, this study aims to monitor movement of Sangihe subduction zones with the latest observation data.This study aims to obtain velocity of Sangihe Islands plate movement during 2017 to 2019. Observation was performed using 3 monitoring control points for 7 days in 2019. While observation data from 2017 to 2018 were obtained from previous studies. Observations was carried out using GNSS differential method technology. Loosely constrained of weighted parameter was performed in least square adjustment of GNSS data daily processing, while Kalman Filtering algorithm applied for combining multiyear GNSS data to estimate the velocity refer to ITRF 2014 using GAMIT/GLOBK.This study indicates that Sangihe Islands has horizontal movement to the Southeast with velocity vector of 1 to 2.16 cm/year. This results confirm the previous studies in that area.
ESTIMASI KOORDINAT TITIK KONTROL PEMANTAUAN DEFORMASI BENDUNGAN SERMO DENGAN METODE PARAMETER BERTAHAP DARI DATA BASELINE HASIL PENGOLAHAN GAMIT Affriani, Asri Ria; Widjajanti, Nurrohmat; Yulaikhah, Yulaikhah
Jurnal Pendidikan Geografi Gea Vol 19, No 2 (2019)
Publisher : Indonesia University of Education

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/gea.v19i2.20715

Abstract

Bendungan Sermo merupakan suatu bangunan struktur yang berfungsi sebagai penampung air untuk air bersih, irigasi pengairan, serta pencegah banjir di Kabupaten Kulon Progo. Oleh karena pentingnya bangunan tersebut, perlu dilakukan pemantauan guna mendeteksi adanya deformasi. Adanya pergerakan geodinamik, perluasan area pemantauan, dan deteksi retakan tanah (crack) memerlukan penambahan jumlah titik kontrol pemantauan deformasi. Penambahan titik kontrol dalam suatu pengukuran dapat mempengaruhi ketelitian hasil pengolahan data sehingga memerlukan strategi khusus pengolahan data. Oleh karena itu, digunakan hitung perataan metode parameter bertahap. Tujuan dari penelitian ini adalah teridentifikasi nilai koordinat 3D dan perbedaan ketelitian titik kontrol pemantaun deformasi yang dihasilkan dari pengolahan dengan metode parameter bertahap serta teridentifikasi signifikansi perbedaan koordinat dan ketelitian hasil pengolahan metode parameter bertahap dengan hasil pengolahan dengan perangkat lunak GAMIT/GLOBK.Penelitian ini menggunakan data pengamatan GNSS 10 titik kontrol pemantauan deformasi Bendungan Sermo yang diukur pada day of year (doy) 250 tahun 2014 selama ± 2 jam dan doy 129 tahun 2015 ± 8 jam. Pengolahan data dilakukan dengan perangkat lunak GAMIT untuk mendapatkan panjang baseline dan ketelitiannya dengan pengikatan lokal pada enam stasiun CORS BIG. Nilai panjang baseline dan ketelitiannya digunakan sebagai input dalam pengolahan dengan hitung perataan parameter bertahap sehingga dihasilkan nilai koordinat titik kontrol pemantauan deformasi dan ketelitannya. Pada perataan bertahap tahap pertama digunakan lima titik kontrol dengan satu titik dianggap fixed. Perataan bertahap tahap kedua ditambahkan lima titik kontrol. Analisis yang dilakukan meliputi analisis perbedaan ketelitian pada titik kontrol pemantauan hasil pengolahan data dengan metode parameter bertahap dan perbandingan koordinat 3D hasil pengolahan metode parameter bertahap dengan hasil pengolahan GAMIT/GLOBK.Analisis perbedaan ketelitian hasil pengolahan data menggunakan metode parameter bertahap menunjukkan bahwa terdapat peningkatan ketelitian pada kelima titik kontrol yang diolah pada tahap pertama. Peningkatan ketelitian berkisar antara 0,193 cm s.d. 5,450 cm. Berdasarkan uji perbandingan dua varian sampel, ketelitian hasil pengolahan tahap pertama berbeda signifikan dengan ketelitian hasil pengolahan tahap kedua. Hasil uji signifikansi beda dua parameter menunjukkan bahwa hasil pengolahan koordinat 3D dengan metode perataan bertahap tidak berbeda signifikan dengan hasil pengolahan dengan perangkat lunak GAMIT/GLOBK secara statistik.