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Journal : JGISE-Journal of Geospatial Information Science and Engineering

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.
Time Variant Adjustment for The Solution of Control Point Unstability in Deformation Analysis of Borobudur Vertical Deformation Monitoring Network Dwi Lestari; Yulaikhah Yulaikhah; Rizki Iman Sari
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.38590

Abstract

Borobudur is Indonesian's cultural heritage which is recognized as a world heritage by UNESCO. As a world heritage structure, monitoring and maintenance have to be carried out periodically at Borobudur. Monitoring the vertical deformation of the temple using Geodetic method is one kind of monitoring which have to be done, in this case the monitoring uses leveling network. The design of leveling network at Borobudur in 2002 used absolute network, but the control point of this network has been indicated to be shifted. The control point displacement would cause a systematic error in the adjustment computation method for the analysis of vertical displacement. The correction of control point elevation due to the vertical shift is needed prior to the adjustment computation using observation model. In addition, there is a time variant adjustment computation method which able to calculate the vertical rate of object point displacement. This study aims to compare the vertical displacement analysis of the Borobudur’s vertical network from the adjustment computation using observation model with the correction of control point height and from time-variant adjustment method.Data used in this study were the elevation differences from leveling measurements in 2002, 2003 and 2004, and the elevation and vertical velocity of the control point in 2002. Adjustment computation using observation model began with the elevation correction of control point at each epoch. The adjustment computation was taken to determine the elevation of monitoring points at each epoch. Statistical test and vertical displacement analysis using significance parameter tests was carried out to analyze the results. Adjustment computation using time-variant method was taken to determine the elevation and the vertical velocity of the monitoring points at certain epoch intervals and validated using global test after the adjustment computation.The vertical displacement magnitude of Borobudur’s monitoring points, resulted from the parameter adjustment computation with the correction of control point compared to the time-variant adjustment results was differed in nanometer.  Time-variant adjustment computation method gave more accurates result of 1.5 times better than the observation model.
Development and Definition of Prambanan Temple Deformation Monitoring Control Points Rochmad Muryamto; Muhammad Iqbal Taftazani; Yulaikhah Yulaikhah; Bambang Kun Cahyono; Anindya Sricandra Prasidya
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.40788

Abstract

Since 1991, Prambanan Temple has been recognized by UNESCO as a cultural heritage of a historic building. In its construction, the Prambanan temple was established in a labile soil structure in the sandy soil and not far from the Opak River. In the geological map of Yogyakarta, there is a fault under the Opak River landscape. This fault under the Opak River has caused an earthquake in 2006. Because of its position in disaster-prone areas, regular monitoring of the geometric aspects of Prambanan Temple is very necessary.This research aims to build a deformation monitoring control point in Prambanan Temple. Eight control points, consist of three existing points and five new points are built around Prambanan Temple. These eight control points then were measured by observing GNSS for 1x24 hours in order to define their coordinates. GNSS data processing is done using GAMIT 10.70 software with two strategies, namely (1) processing with regional binding points, in this case using IGS BAKO and JOG2 stations, and (2) processing with global binding points using IGS COCO station reference points, DARW, KARR, POHN, PIMO, DGAR, and IISC. This research yields the establishment of Prambanan temple deformation control points and their coordinates and standard deviation in two processing strategies. The smallest standard deviation in the first strategy is 0.0787 m on the Z-axis for points of PRO1 and PR03. The biggest standard deviation is 0.1218 m on the Y-axis at point of PR02. In the second strategy the smallest standard deviation is 0.0036 m on the Z-axis for points of PR01 and PR03. The biggest standard is 0.0141 m on the Y-axis at point of PR02.
Determination of Boiler Building Verticality in Power Plant Construction using Terrestrial Laser Scanner (TLS) Mohamad Bagas Setiawan; Yulaikhah Yulaikhah; Ruli Andaru
Jurnal Geospasial Indonesia Vol 2, No 1 (2019): June
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jgise.40846

Abstract

Nowadays, Indonesian government is focusing on build up infrastructures, especially power plant infrastructures to fulfil electrical energy needs. One of the power plants that will be built up is Waai power plant which located on Waai village, Maluku Province. Waai power plant had been postponed since 2014. In order to build this power plant, the advisability of the building needed to be checked from its verticality level. This level was determined by Terrestrial Laser Scanner (TLS). The TLS’s point clouds were registered using two methods, there are target to target and cloud to cloud methods. There are 65 beams on the power plant boiler building, but only 31 beams that used as the samples to assign the verticality of the boiler construction. The verticality level was set on the X-axis, Y-axis, and the resultant of the X and Y axis by using Pythagoras theorem after the bottom and top coordinates from each beam was determined. The Queensland Building and Construction Admission Standards and Tolerances Guide 2016 was used as tolerance of verticality level. The result of the verticality calculation presented on the X-axis consisted from -0ᵒ 1’ 26,678” to 0ᵒ 4’ 11,778” with the average was 0ᵒ 1’ 40,820” and major direction pointed the positive axis. On the Y-axis, the average was -0ᵒ 0’ 45,772” with -0ᵒ 3’ 33,345” as minimum and 0ᵒ 1’ 25,319” as the maximum and the major direction went to the negative axis. The verticality on the resultant of X and Y axis was from 0ᵒ 0’ 45,225” until 0ᵒ 4’ 15,674” with the average was 0ᵒ 2’ 27,057” and the direction was to the southeast. After the verticality number was compared with the tolerance, the verticality level was smaller than the standard on each beam. From the result, we can conclude that the boiler building on the Waai power plant can be categorized safe to reconstruct.
Calculation Of Sedimentation Rate at Sempor Reservoirs in 2018 Using Modified Universal Soil Loss Equation Method (MUSLE) Septi Arini; Yulaikhah Yulaikhah; Bambang Kun Cahyono
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.51156

Abstract

Sempor Reservoir located in the Telomoyo River Basin in the Serayu River region is categorized as one of the priority watersheds based on the 2015-2019 Strategic Plan of the Ministry of Environment and Forestry. Priority watershed is a watershed that gets more attention in controlling water pollution, one of which is sedimentation. Watershed observation and management activities are needed for the reservoir to operate optimally. One of the observations and management activities of the Sempor Watershed is the calculation of sedimentation rate. In this research the sedimentation rate was calculated using the MUSLE method that included runoff parameter, erodibility, slope, land cover and conservation factor. The Sempor watershed boundary is obtained through delineation of DEM. The calculation is done by utilizing a Geographic Information System (GIS) through analysis of soil type maps, length and slope maps,  land cover and conservation maps with the boundaries of the Sempor Reservoir. Based on this result, the Sempor Reservoir has a sedimentation rate of 166,173,500 tons/year and a sedimentation thickness rate of 3,7259 mm/year. According to the provisions of the Ministry of Forestry in 2009, the rate of sedimentation thickness in the Sempor Reservoir is included in the medium class. The river as one of the potential means of sediment transport contributes to the rate of sediment thickness of 3.7256 mm /year, while for areas outside the river coverage it only 0.003 mm/year. The river has a major influence on sedimentation in the Sempor Reservoir.
Evaluasi Pola Pergeseran Stasiun CORS untuk Keperluan Pemantauan Deformasi Sesar Baribis Widyatma, Tata Mulya; Yulaikhah, Yulaikhah
Jurnal Geospasial Indonesia Vol 8, No 1 (2025): June
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jgise.106603

Abstract

Letak Indonesia yang berada pada pertemuan empat lempeng yaitu Eurasia, Indo-Australia, Laut Filipina, dan Pasifik menyebabkan tingginya aktivitas tektonik termasuk terbentuknya sesar-sesar, salah satunya Sesar Baribis. Pergerakan sesar ini dapat diamati dengan pengamatan GNSS. Penelitian sebelumnya menggunakan data CORS untuk mengidentifikasi pola pergerakan Sesar Baribis. Penggunaan data stasiun CORS memiliki keunggulan yaitu data tersedia secara kontinu, namun CORS tidak dirancang khusus untuk memantau pergerakan sesar tersebut. Oleh karena itu perlu dilakukan evaluasi apakah stasiun CORS dapat mewakili pergerakan sesar tersebut. Penelitian ini menggunakan data tujuh stasiun CORS di sekitar Sesar Baribis pada tahun 2019 s.d. 2023 dan data campaign pengamatan GNSS di sekitar Sesar Baribis pada tahun 2019 s.d. 2021. Data tersebut diolah dengan metode Precise Point Positioning (PPP), kemudian dilakukan analisis laju dan arah pergeseran. Laju pergeseran dihitung dengan metode linear square adjustment. Evaluasi pergerakan CORS apakah dapat merepresentasikan pergerakan sesar atau tidak dilakukan dengan membandingkan pola kecepatan dan arahnya terhadap titik campaign yang memang didesain untuk pemantauan. Hasil penelitian menunjukkan bahwa titik pantau campaign secara keseluruhan memiliki laju pergeseran yang lebih besar dibandingkan dengan CORS. Sementara itu, arah pergeseran komponen horizontal titik CORS secara umum mengarah ke timur, sedangkan titik pantau campaign memiliki arah yang cukup beragam. Pola pergerakan stasiun CORS di sekitar Sesar Baribis tidak menunjukkan kesesuaian dengan tipe Sesar Baribis yaitu sesar naik, sekaligus tidak menunjukkan kesesuaian dengan pola laju dan arah pergeseran titik campaign. Dapat dikatakan bahwa stasiun CORS tidak merepresentasikan pola pergerakan Sesar Baribis.