Journal of Geospatial Science and Technology

Uji Akurasi Hasil Pengukuran GNSS Metode Statik dan RTK-NTRIP dengan Referensi CORS GMU2

Anandito Hardiyoso, Muhammad Iqbal Taftazani — Thu, 31 Jul 2025 00:00:00 +0700

Global Navigation Satellite Systems (GNSS) technology continues to develop, including in terms of supporting infrastructure development. One of the latest infrastructure developments is the establishment of the GMU2 Continuous Operating Reference Systems (CORS) station on October 14, 2023, the result of cooperation between DTK Vocational School UGM and PT Kantara Group. This applicative activity aims to test the accuracy of GNSS measurements using static and RTK-NTRIP methods with the CORS GMU2 reference and compare it with CORS JOGS in Yogyakarta. GNSS data was obtained from nine measurement points using static and RTK-NTRIP methods with CORS GMU2 and JOGS as reference stations. The static method refers to the SNI standard Horizontal Control Net with a recording interval of 15 seconds for 20 minutes, while RTK-NTRIP uses real-time correction via the internet. Analysis was conducted through the calculation of standard deviation, RMSE, and significance test of coordinate differences. The results show that the static method with the GMU2 reference produces standard deviations of the Easting component of 0.03 cm to 0.09 cm, Northing of 0.02 cm to 0.09 cm, and height of 0.05 cm to 0.17 cm. The RTK-NTRIP method produces standard deviations of the Easting component of 0.12 cm to 4.46 cm, Northing of 0.11 cm to 5.00 cm, and height of 0.21 cm to 6.77 cm. Although the precision of GMU2 CORS is quite good, its accuracy is lower than that of JOGS CORS, with significant differences at some points. The total RMSE for the static method reached 37.565 cm, while the RTK-NTRIP method ranged from 41.010 cm to 42.572 cm. Significance tests showed significant differences at most points, with null hypothesis rejection of 100% for the static method and 78 to 81% for RTK-NTRIP. In conclusion, further evaluation is needed to ensure the reliability of GMU2 CORS as a reference station.

Pengamatan Lendutan Vertikal Jembatan Krasak Secara Kontinu dengan Teknologi GNSS

Jaka Putra Sakti, Muhammad Iqbal Taftazani — Thu, 31 Jul 2025 22:00:40 +0700

The Krasak Bridge, located on the border between the Special Region Province of Yogyakarta and Central Java, is the main access between Yogyakarta and Central Java. In accordance with the Regulation of the Minister of Public Works and Public Housing No. 41 of 2015, it is necessary to conduct a feasibility test on this bridge. This study aims to analyze whether the deflection on the Krasak Bridge meets the deflection requirements in RSNI T03 2005. Observations are made directly with the traffic load to get more accurate data, Observations are made at three points, namely TL10, TL20, and TL30, which are located at the two ends and center of the bridge. The method used is rapid static for 15 to 20 minutes, as well as observation of the number of vehicles passing through the bridge along with GNSS measurement. The observation results showed varying changes in elevation/vertical deflection with a maximum deflection of 0.1512 meters in TL10, 0.1760 meters in TL20, and 0.194 meters in TL30. The standard high deviation of kinematic post processing results with RTKLIB software is 1.2 cm. Based on the technical calculation of the bridge loading at RSNI T03 in 2006, the maximum tolerance allowed is 0.28 meters. Therefore, the deflection that occurs on the Krasak Bridge still meets the applicable standards.

Deteksi Deformasi Vertikal Permukaan Jembatan Mulya Agung Tahun 2021 – 2022 Menggunakan Data Mobile Laser Scanner

Wulan Ratna Mayangsari, Ruli Andaru — Thu, 31 Jul 2025 00:00:00 +0700

The Terbanggi Besar - Pematang Panggang - Kayu Agung Toll Road (TBPPKA) is a part of the Trans-Sumatra Toll Road (JTTS) that has been operational since November 2019, necessitating road maintenance. Routine maintenance is carried out on all toll road assets, including the Mulya Agung Underpass Bridge on the TBPPKA Toll Road at KM 240+822. This study aims to analyze vertical deformations on the bridge's surface using Mobile Laser Scanner (MLS) as a step in bridge monitoring and maintenance efforts. MLS technology was chosen for its capability in fast and accurate scanning, making it effective for multi-epoch measurements. Data generated from the MLS measurements come in the form of a point cloud, which still needs to be registered using the Iterative Closest Point (ICP) method to ensure the data is in the same coordinate system. Based on the research results, the RMS accuracy value in the registration process is 0.021 meters out of a total of 596,963 points sampled. To determine the presence of vertical deformation, a significant test was conducted using the Student's t-test. Based on the significant test results with a 95% confidence level, the calculated t-value (2.705) was found to be greater than the tabulated t-value (2.010), indicating a significant change in elevation. The maximum elevation increase is 9.1 cm on the south side of the bridge, while the minimum decrease is -3.4 cm on the north side of the bridge. Vertical deformations occur at the end of the bridge connected to the road, which is attributed to repairs involving asphalt addition. The MLS method has proven to be effective in detecting vertical deformations on the bridge with a level of detection of 2 cm.