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All Journal Indonesian Journal of Geography GEA, Jurnal Pendidikan Geografi JURNAL ILMIAH GEOMATIKA Communications in Science and Technology BHUMI: Jurnal Agraria dan Pertanahan International Journal of Remote Sensing and Earth Sciences (IJReSES) JGISE-Journal of Geospatial Information Science and Engineering Jurnal Nasional Teknologi Terapan Jurnal Teknik Sipil Kokoh Geoid - Journal of Geodesy and Geomatics
Nurrohmat Widjajanti
Departemen Teknik Geodesi, Fakultas Teknik, Universitas Gdjah Mada
Agriculture, Biological Sciences & Forestry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Education Electrical & Electronics Engineering Engineering Environmental Science Law, Crime, Criminology & Criminal Justice Mathematics Social Sciences Transportation

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Journal : JGISE-Journal of Geospatial Information Science and Engineering

 1 
Correlation of GNSS Observation Data Quality Resulted from TEQC Checking and Coordinate’s Precision Yulaikhah Yulaikhah; Subagyo Pramumijoyo; Nurrohmat Widjajanti
Jurnal Geospasial Indonesia Vol 1, No 1 (2018): June
Publisher : 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 Nurrohmat Widjajanti; Sherly Shinta Emalia; Parseno Parseno
Jurnal Geospasial Indonesia Vol 1, No 1 (2018): June
Publisher : 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 Hilmiyati Ulinnuha; Aris Sunantyo; Nurrohmat Widjajanti
Jurnal Geospasial Indonesia Vol 1, No 2 (2018): December
Publisher : 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 Hilmiyati Ulinnuha; Dwi Lestari; Leni Sophia Heliani; Nurrohmat Widjajanti; Cecep Pratama; Parseno Parseno; Krishna Fitranto Nugroho
Jurnal Geospasial Indonesia Vol 2, No 2 (2019): December
Publisher : 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.
Analisis Tingkat Ketersediaan dan Cakupan dari Continuously Operating Reference Station (CORS) di Pulau Jawa Novie Chiuman; Dedi Atunggal; Nurrohmat Widjajanti
Jurnal Geospasial Indonesia Vol 4, No 1 (2021): June
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jgise.63277

Abstract

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 Telkomsel baik untuk metode RTK single base maupun network base yaitu masing-masing sebesar 34,622% dan 45,180%. Cakupan riil dari estimasi tersebut mungkin lebih besar karena hasil uji lapangan membuktikan bahwa tingkat ketepatan data dari OpenSignal hanya sebesar 69,444% dan masih banyak area tanpa data sinyal. Hasil analisis tingkat duplikasi cakupan CORS menunjukkan bahwa luas duplikasi cakupan CORS untuk metode RTK single base dan network base masing-masing sebesar 37,076% dan 82,382% dari luas total cakupan CORS. Hasil dari penelitian juga menunjukkan setidaknya ada 20 stasiun CORS yang perlu ditingkatkan ketersediaan datanya.
Pergerakan Vertikal Titik GNSS CORS Pantai Utara Jawa Tengah dan Sekitarnya Tahun 2021-2023 Menggunakan Pengolahan Metode Precise Point Positioning (PPP) Sitaningrum, Alya; Widjajanti, Nurrohmat
Jurnal Geospasial Indonesia Vol 7, No 1 (2024): June
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jgise.95957

Abstract

Penurunan tanah di Pantai Utara Jawa Tengah dan sekitarnya menimbulkan kerugian dan berdampak negatif. Mitigasi seperti pemantauan fenomena penurunan tanah di Pantai Utara Jawa Tengah diperlukan khususnya untuk pemantauan pergerakan vertikal dan kecepatannya. Salah satu teknologi yang dapat dimanfaatkan yaitu Global Navigation Satellite System (GNSS). Saat ini, pengolahan data GNSS dengan metode Precise Point Positioning (PPP) telah banyak digunakan untuk analisis pergerakan vertikal. Berdasarkan koordinat hasil pengolahan data GNSS beberapa tahun dapat ditentukan kecepatan pergerakan vertikalnya. Tujuan penelitian ini untuk menentukan nilai pergerakan vertikal dan kecepatannya pada titik Continuously Operating Reference Stations (CORS) di Pantai Utara Jawa Tengah dan sekitarnya dengan metode PPP. Pemantauan pergerakan vertikal dilakukan pada delapan titik GNSS CORS tahun 2021 s.d. 2023 di Pantai Utara Jawa Tengah yaitu CPKL (Pekalongan), CSMG (Semarang Genuk), CSEM (Semarang), dan CJPR (Jepara) dan di sekitarnya yaitu CBJN (Banjarnegara), CMGL (Magelang), CSLO (Solo), dan CPWD (Purwodadi). Pengolahan data GNSS dengan metode PPP menggunakan perangkat lunak PRIDE PPP-AR sehingga diperoleh estimasi nilai koordinat harian dan simpangan baku. Pergerakan vertikal dan simpangan bakunya diolah dengan metode linear least square sehingga diperoleh nilai kecepatan pergerakan vertikal dan simpangan baku setiap titik CORS kemudian dilakukan uji statistik t-student dengan tingkat kepercayaan 95%. Penurunan tanah tahun 2021 s.d. 2022 terjadi pada titik CPKL, CPWD, CSEM, dan CSMG sedangkan CBJN, CJPR, CMGL, dan CSLO terjadi kenaikan tanah. Tahun 2022 s.d. 2023 dan 2021 s.d. 2023 terjadi penurunan tanah di titik CMGL, CPKL, CPWD, dan CSMG sedangkan CBJN, CJPR, CSEM, dan CSLO mengalami kenaikan tanah. Nilai kecepatan pergerakan vertikal selama tiga tahun berkisar -4,39 s.d. -94,03 mm/tahun sedangkan kenaikannya -4,39 s.d. 96,32 mm/tahun. Penurunan tanah terjadi pada titik CMGL, CPKL, CPWD, dan CSMG. Kenaikan tanah terjadi pada titik CBJN, CJPR, CSEM, dan CSLO berturut-turut sebesar 54,24 mm/tahun, 96,32 mm/tahun, 3,23 mm/tahun, 26,6 mm/tahun.
Co-Authors Affriani, Asri Ria Aris Sunantyo Atunggal, Dedi Azizi, Iqbal Hanun Cecep Pratama Dwi Lestari Dwi Lestari Fitri, Listiyo Heliani, Leni Sophia Himawan, Iwan Qodar Krishna Fitranto Nugroho M. Ellya Putriningtias Made Ditha Ary Sanjaya Margaretha Elya Lim Putraningtyas Muhammad Iqbal Taftazani Novie Chiuman Parseno Parseno Parseno Parseno Parseno Parseno Sherly Shinta Emalia Sitaningrum, Alya Subagyo Pramumijoyo Subagyo Pramumijoyo Sunantyo, Aris T. Aris Sunantyo Trias Aditya Trias Aditya, Trias Ulinnuha, Hilmiyati Ulinnuha, Hilmiyati Waliyanto Waliyanto, Waliyanto Widya Hanifazza Yulaikhah Yulaikhah