Analisis Monitoring Ketinggian Air Menggunakan Low-Cost GNSS Interferometric Reflectometry (Studi Kasus: Perairan Sungai PT Garam, Kabupaten Pamekasan)

Bawasir, Arizal (2023) Analisis Monitoring Ketinggian Air Menggunakan Low-Cost GNSS Interferometric Reflectometry (Studi Kasus: Perairan Sungai PT Garam, Kabupaten Pamekasan). Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Eksplorasi sinyal Global Navigation Satellite System (GNSS) telah dilakukan di berbagai bidang ilmu dan pengembangan penelitian. Salah satu eksplorasi terbaru terhadap sinyal GNSS adalah GNSS Interferometric Reflectometry (GNSS-IR) yang memanfaatkan sinyal multipath untuk menghitung jarak vertikal dari permukaan pantul menuju antena/receiver geodetik. Namun, perangkat geodetik memiliki limitasi yaitu harganya yang relatif mahal. Sehingga pada penelitian ini digunakan perangkat low-cost GNSS untuk melakukan monitoring ketinggian air sungai di PT Garam Pamekasan menggunakan metode GNSS-IR. Perhitungan ketinggian permukaan laut dengan pengamatan GNSS-IR didasarkan pada penentuan peak frequency pada periodogram yang dihasilkan dari ekstraksi data signal-to-noise ratio (SNR). Metode pengamatan GNSS-IR pada penelitian ini yaitu dengan menggunakan dua antena dan dua receiver. Kedua teknik pengamatan tersebut dilakukan dengan pengaturan orientasi antena tegak (zenith-looking) dan miring menghadap sungai (horizon-looking) untuk mengevaluasi perbandingan karakteristik sinyal multipath serta evaluasi akurasinya terhadap pengamatan tide gauge konvensional. Berdasarkan hasil analisis, pengamatan antena miring memiliki performa yang lebih baik daripada pengamatan antena tegak, baik dari segi kualitas multipath yang diterima, jumlah data ketinggian yang diperoleh, maupun ketelitian yang dihasilkan. Dengan mengatur konfigurasi antena menjadi miring, amplitudo pada SNR menjadi lebih tinggi, sehingga ketelitian data retrieval ketinggian permukaan air sungai yang dihasilkan menjadi lebih tinggi. Analisis pasang surut juga dilakukan pada penelitian ini, mengingat lokasi sungai PT Garam yang cukup dekat dengan laut. Tipe pasang surut yang dihasilkan berada pada rentang yang serupa (baik pada pengamatan antena tegak, miring, maupun tide gauge), yaitu pada tipe pasang surut campuran condong harian ganda. Hasil rekonstruksi dan prediksi pasang surut menunjukkan performa yang lebih baik pada observasi antena miring, yang mana hal ini berbanding lurus dengan kualitas data dan ketelitiannya. Dengan demikian, penggunaan perangkat low-cost GNSS untuk monitoring GNSS-IR di perairan sempit memiliki performa yang memuaskan, khususnya pada konfigurasi antena miring.
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Global Navigation Satellite System (GNSS) signal exploration has been carried out in various fields of science and research development. One of the newest explorations of GNSS signals is GNSS Interferometric Reflectometry (GNSS-IR) which utilizes multipath signals to calculate the vertical distance from the reflecting surface to the geodetic antenna/receiver. However, scientific-grade or geodetic GNSS instruments are expensive, which is a limiting factor for their prompt and more widespread deployment as a dedicated environmental sensor. Hence, in this study, low-cost GNSS devices was used to monitor river water levels at PT Garam Pamekasan using the GNSS-IR method. Calculation of sea level height with GNSS-IR observations is based on determining the peak frequency on the periodogram resulting from signal-to-noise ratio (SNR) data extraction. The GNSS-IR observation method in this study is by using two antennas and two receivers. The two observation techniques are carried out by setting the antenna orientation vertically (zenith-looking) and obliquely facing the river (horizon-looking) to evaluate the comparison of the characteristics of the multipath signal and its accuracy against conventional tide gauge observations. Based on the results of the analysis, oblique antenna observations have better performance than upright antenna observations, both in terms of the quality of the multipath received, the amount of data retrieval obtained, and the resulting accuracy. By setting the antenna configuration to be tilted, the amplitude of the SNR becomes higher, so that the accuracy of the resulting data retrieval becomes higher. Tidal analysis were also analysed in this study, considering the location of PT Garam's river is quite close to the sea. The type of tides produced are in a similar range. The observations of upright, oblique, and tide gauge antennas have the mixed semidiurnal tide type. The results of the tidal reconstruction show better performance on oblique antenna observations, which is directly proportional to the quality of the data and its accuracy. Thus, the use of low-cost GNSS devices for GNSS-IR monitoring in narrow waters has a satisfactory performance, especially for horizon-looking antenna configurations.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Low-cost GNSS-IR, signal-to-noise ratio, periodogram, konfigurasi antena, ketinggian muka air sungai.
Subjects:	G Geography. Anthropology. Recreation > G Geography (General) > G109.5 Global Positioning System G Geography. Anthropology. Recreation > GE Environmental Sciences T Technology > T Technology (General) > T57.5 Data Processing T Technology > TC Hydraulic engineering. Ocean engineering > TC424 Water levels
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geomatics Engineering > 29101-(S2) Master Thesis
Depositing User:	Arizal Bawasir
Date Deposited:	02 Aug 2023 01:31
Last Modified:	02 Aug 2023 01:31
URI:	http://repository.its.ac.id/id/eprint/99334

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